ARTICLE | doi:10.20944/preprints202306.0293.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Pseudomonas aeruginosa; chronic infection; respiratory; murine model; in vivo; S. aureus
Online: 5 June 2023 (09:50:00 CEST)
Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen and is the leading cause of infection in patients with cystic fibrosis (CF). The ability of P. aeruginosa to evade host responses and develop into chronic infection causes significant morbidity and mortality. Several mouse models have been developed to study chronic respiratory infections induced by P. aeruginosa, with the bead agar model being the most widely used. However, this model has several limitations, including the requirement for surgical procedures and high mortality rates. Herein, we describe novel and adapted biologically relevant models of chronic lung infection caused by P. aeruginosa. Three methods are described, a clinical isolate infection model, utilizing isolates obtained from patients with CF, an incomplete antibiotic clearance model, leading to bacterial bounce-back and the establishment of chronic infection, and an adapted water bottle chronic infection model. These models circumvent the requirement for surgical procedure and importantly, can be induced with clinical isolates of P. aeruginosa and in wild-type mice. We also demonstrate successful induction of chronic infection in the transgenic βENaC murine model of CF. We envisage that the models described will facilitate the investigations of host and microbial factors, and the efficacy of novel antimicrobials, during chronic P. aeruginosa respiratory infections.
ARTICLE | doi:10.20944/preprints202306.0270.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Mycoplasma pneumoniae; CC16; CCSP; CC10; mass spectrometry; remodeling
Online: 5 June 2023 (08:28:04 CEST)
CC16 plays many protective roles within the lung; however, the complete biological functions, es-pecially regarding the pulmonary epithelium during infection, remain undefined. We have previ-ously shown that CC16 deficient (CC16-/-) mouse tracheal epithelial cells (MTECs) have enhanced Mp burden, compared to CC16 sufficient (WT) MTECs; therefore, in this study, we wanted to fur-ther define how the pulmonary epithelium responds to infection in the context of CC16 deficiency. Using mass spectrometry and quantitative proteomics to analyze proteins secreted apically from MTECs grown at an air-liquid interface, we investigated the protective effects that CC16 elicits within the pulmonary epithelium during Mycoplasma pneumoniae (Mp) infection. When chal-lenged with Mp, WT MTECs have an overall reduction in apical protein secretion, whereas CC16-/- MTECs have increased apical protein secretion compared to their unchallenged controls. Fol-lowing Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) assessment, many of the proteins upregulated from CC16-/- MTECS (unchallenged and during Mp infection) were related to airway remodeling, which were not observed by WT MTECs. These findings sug-gest that CC16 is instrumental in providing protection within the pulmonary epithelium during respiratory infection with Mp, the major causative agent of community-acquired pneumoniae.
COMMUNICATION | doi:10.20944/preprints202306.0189.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: RNA-seq; COVID-19; SARS-CoV-2; gene enrichment analysis; enriched pathways; differentially expressed genes; transcriptomics
Online: 2 June 2023 (11:12:22 CEST)
During the infection by SARS-CoV-2, the virus is changing infected host cell into its own factory producing new viral particles. As infection progresses, infected cell undergoes many changes in various pathways. One of the events caused by changes is cytokine storm, which leads to the severe symptoms. In this study, we investigated transcriptomic changes caused by COVID-19 disease using RNA-seq data obtained from COVID-19-positive patients and COVID-19-negative donors. RNA-seq data were collected for the purpose of identification of potential biomarkers associated with a different course of the disease. Here, the first datasets of 96 samples were analyzed to validate the methods. The aim of this publication is to report pilot results. In search of potential biomarkers associated with different disease severity, we performed differential expression analysis of human transcriptome, focusing on COVID-19 positivity and symptom severity. Since we detected plenty of potential biomarkers, we performed KEGG enrichment analysis to get better view of altered pathways. Results show, that affected were pathways related to immune processes and response to infection, also multiple signaling pathways, while most of them were also reported to be influenced by SARS-CoV-2 infection in previous studies.
ARTICLE | doi:10.20944/preprints202305.2212.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: GBS; Antibiotic susceptibility pattern; pregnant women; Wolaita Sodo; Ethiopian
Online: 2 June 2023 (04:53:16 CEST)
Background: Streptococcus agalactiae or Group B Streptococcal colonization of the gastrointestinal and genital tracts of pregnant women usually remains asymptomatic; even if it is the critical determinant of infection in neonates and young infants. It causes early and late onset of invasive Group B Streptococcus (GBS) disease manifesting as septicemia, meningitis and pneumonia. Now it is recognized as an important cause of maternal and neonatal morbidity and mortality in many parts of the world including Ethiopia where the magnitude of the problem has been little studied. The aim of this study was to assess the prevalence of GBS colonization, to identify associated risk factors and antimicrobial susceptibility pattern among pregnant women at selected health facilities of Wolaita Sodo Town, Southern Ethiopia. Methodology: A health facility based cross-sectional study design was conducted at WSUCSH & Wolaita Sodo Health Center from June to August, 2022. A total of 279 pregnant women who were in ANC follow up with at 35-37 weeks of gestation were included. For GBS isolation, recto-vaginal swabs were inoculated in 1ml Todd-Hewitt broth medium supplemented with 10μg/ml colistin and 15μg/ml nalidixic acid and followed by identification of isolates based on colonial morphology, gram stains, catalase reaction and CAMP tests. Antimicrobial susceptibility testing was performed using modified Kirby–Bauer disk diffusion method. All collected data were organized in Epi info 184.108.40.206, then transfer tabulated using SPSS version 20. Logistic regression analysis was used to see the association between variables. Finally, the p-value < 0.05 were considered statistically significant. Results: In present study, 279 pregnant mothers included and their age was between 15 to 38 years with a mean of 26.5 ± 4.5 years. Of all participants, the highest 120 (43.01%) were housewives. The overall carriage rate of GBS was 67(24.0%). GBS colonization showed a statistically significant association with college and above levels of maternal education [AOR= 6.610, 95% CI (1.724 - 25.349), P=0.01]. High susceptibility of GBS isolate was seen to Penicillin G & Chloramphenicol (92.5%) for each, Ampicillin, and Ceftriaxone (89.6%) each, following Vancomycin (74.62%), and Erythromycin (77%). Relatively, GBS showed high resistance to Tetracycline (88 %). Conclusion: In this study, the overall prevalence of GBS colonization was 24.0%. College and above educational level was statistically significant with GBS colonization. This study used to give attention to the management of pregnant women by making GBS culture one of the routine diagnoses during ANC follow-up and to prevent infection by early detection.
ARTICLE | doi:10.20944/preprints202305.2247.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: lung microbiome; bronchoalveolar lavage fluid (BALF); antagonistic bacteria; biocontrol; Pseudomonas aeruginosa; aspergillosis
Online: 31 May 2023 (12:52:50 CEST)
Fungi of the genus Aspergillus are widespread in the environment where they produce large quantities of airborne conidia. Inhalation of Aspergillus spp. conidia in immunocompromised individuals can cause a wide spectrum of diseases, ranging from hypersensitivity responses to lethal invasive infections. Upon deposition in the lung epithelial surface, conidia encounter and interact with complex microbial communities that constitute the lung microbiota. The lung microbiota has been suggested to influence the establishment and growth of Aspergillus spp. in the human airways. However, the mechanisms underlying this interaction have not yet been sufficiently investigated. In this study, we aimed to evaluate the presence of commensal bacteria antagonistic to Aspergillus in the lung. To this end, we enriched and isolated bacterial strains able to inhibit the germination of conidia from bronchoalveolar lavage fluid (BALF) samples of lung transplant recipients. We used a novel enrichment method based on a soft agar overlay plate assay in which bacteria are directly in contact with conidia and for which inhibition can be readily observed during enrichment. We isolated a total of five bacterial strains, identified as Pseudomonas aeruginosa, and able to inhibit the germination and growth of Aspergillus fumigatus in a soft agar confrontation assay, as well as in a high-throughput multiplate assay. Moreover, we also showed a strong inhibition of A. fumigatus growth on Calu-3 cell culture monolayers. However, the isolated P. aeruginosa strains were shown to cause significant damage to the cell monolayers. Overall, we validated this novel one-step enrichment approach for the isolation of bacterial strains antagonistic to A. fumigatus from BALF samples. This opens up a new venue for targeted enrichment of antagonistic bacterial strains against specific fungal pathogens.
ARTICLE | doi:10.20944/preprints202305.2229.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: KPC; blood culture; short-term culture; MALDI-TOF MS
Online: 31 May 2023 (10:50:42 CEST)
Carbapenemase resistance in Enterobacterales is a global public health problem and rapid and effective methods to detect resistance mechanisms are needed urgently. Our aim was to evaluate the performance of a MALDI-TOF MS based KPC detection protocol from patients’ positive blood cultures, short-term cultures and colonies at health care settings. Bacterial identification and KPC detection were achieved after protein extraction with organic solvents and target spot loading with suitable organic matrices. Confirmation of KPC production was performed by susceptibility tests, blaKPC amplification by PCR and sequencing. KPC direct detection (KPC-peak at approximately 28.681 Da) from patients’ positive blood cultures, short-term cultures and colonies, once bacterial identification was achieved, showed an overall sensibility and specificity of 100% (CI95: [95%,100%] and CI95: [99%, 100%], respectively). Concordance between hospital routine bacterial identification protocol and identification with this new methodology from the same extract used for KPC detection was ≥92%. This study represents the pioneering effort to directly detect KPC using MALD-TOF MS technology, conducted on patient-derived samples obtained at the hospitals for validation purposes, in a multi-resistance global context that requires concrete actions to preserve available therapeutic options and reduce the spread of antibiotic resistance markers.
ARTICLE | doi:10.20944/preprints202305.2205.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Rotavirus; vaccines; histo-blood groups; immunogenicity; Zambia
Online: 31 May 2023 (08:43:17 CEST)
Live-attenuated, oral rotavirus vaccines have significantly reduced rotavirus-associated diarrhoea morbidity and infant mortality. However, vaccine immunogenicity is diminished in low-income countries. We investigated whether maternal and infant intrinsic susceptibility to rotavirus infection via histo-blood group antigen (HBGA) profiles influenced rotavirus (ROTARIX®) vaccine-induced responses in Zambia. We studied 135 mother-infant pairs under a rotavirus vaccine clinical trial aged 6 to 12 weeks at pre-vaccination up to 12 months old. We determined maternal and infant ABO/H, Lewis, and secretor HBGA phenotypes, and infant FUT2 HBGA genotypes. Vaccine immunogenicity was measured as anti-rotavirus IgA antibody titres. Overall, 34 (31.3%) of children were seroconverted at 14 weeks, and no statistically significant difference in seroconversion was observed across the various HBGA profiles in early infant life. We also observed a statistically significant difference in rotavirus-IgA titres across infant HBGA profiles at 12 months though no statistically significant difference was observed between study arms. There was no association between maternal HBGA profiles and infant vaccine immunogenicity. Overall, infant HBGA was associated with RV-Vaccine immunogenicity at 12 months as opposed to early infant life. Further investigation into the low efficacy of ROTARIX® and appropriate intervention is key to unlocking full vaccine benefits for U5 children.
ARTICLE | doi:10.20944/preprints202305.2193.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Tuberculosis; Drug Resistant; Management; Awareness
Online: 31 May 2023 (08:00:05 CEST)
Background: Although Tuberculosis (TB) is one of the oldest diseases known to mankind, many practitioners are still unaware of various aspects of management of TB including drug resistant TB. To be able to make an impact on the disease burden we need to understand the knowledge, attitude and practices (KAP) of practitioners, both in government and private sector, towards TB case management. Methodology: A random cross-sectional survey of 99 respondents to assess the KAP towards TB case management using a digital semi-structured questionnaire which was pre-tested and administered to allopathic practitioners from across States in North and Central India. Results: 77% responders were government doctors and 23% were private practitioners. Chest physicians accounted for 61% of the responders. 26% of government and 78% of private doctors relied on sources which are difficult to validate for their knowledge on drug resistant TB management. There were large variations seen in knowledge on modes of transmission, standard precautions, extent of drug resistant TB, diagnostics as well as treatment regimen for drug resistant TB. Conclusion: The knowledge of both sector doctors especially amongst private practitioners with respect to the awareness of extent, diagnosis, and treatment and infection control measures for drug resistant TB is suboptimal which translates to poor diagnostic, therapeutic and infection control choices amongst private practitioners. If India has to achieve the targets for TB Elimination by 2025, serious work needs to be done to upgrade the knowledge of the private sector doctors on drug resistant tuberculosis. The Ministry of Health and Family Welfare, GoI needs to have regular educational programs for the private practitioners coupled with awareness campaigns and frequent surveys to assess the knowledge, attitude and practices being followed in the private sector for TB management including drug resistant TB.
ARTICLE | doi:10.20944/preprints202305.2104.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Lysosomal storage diseases; Mucopolysaccharidoses; Glycosaminoglycans; Leukocytes; Lymphocytes
Online: 30 May 2023 (10:01:40 CEST)
Mucopolysaccharidoses (MPSs) are rare inherited lysosomal storage diseases (LSDs) caused by deficient activity in one of the enzymes responsible for glycosaminoglycans lysosomal degradation. MPS II is caused by pathogenic mutations in the IDS gene, leading to deficient activity of the enzyme iduronate-2-sulfatase, which causes dermatan and heparan sulfate storage in the lysosomes. MPS VI has dermatan sulfate lysosomal storage, owing to a deficiency of arylsulfatase B, due to pathogenic mutations in the ARSB gene. Alterations in the immune system of MPSs mouse models have been described but the data is still scarce concerning MPSs patients. Herein, we study different leukocyte populations in MPS II and VI disease patients. MPS VI, but not MPS II patients, have a decrease percentage of Natural Killer (NK) cells and monocytes when compared with controls. No alterations were identified in the percentage of T, invariant NKT and B cells in both groups of MPS disease patients. However, we uncovered alterations in the naïve versus memory status of both helper and cytotoxic T cells in MPS VI disease patients compared to control group. Indeed, MPS VI disease patients have a higher frequency of naïve T cells and consequently lower frequency of memory T cells than control subjects. Altogether, these results reveal MPS VI disease-specific alterations in some leukocyte populations, suggesting that the type of substrate accumulated and/or enzyme deficient in the lysosome may have a particular effect on the normal cellular composition of the immune system.
ARTICLE | doi:10.20944/preprints202305.1994.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: brain; metastasis; breast cancer; interferon-; blood-brain barrier; immune response; T lymphocytes
Online: 29 May 2023 (08:24:41 CEST)
The appearance of brain metastasis is the most serious complication of breast cancer with mostly fatal outcomes. To reach the brain, tumor cells need to pass the blood-brain barrier (BBB). The molecular mechanisms underlying penetration of the BBB are largely unknown. Previously we found that tumor-infiltrating T lymphocytes enhance the development of brain metastasis of estrogen receptor-negative (ER-) breast cancer. In the current study, we investigate the contribution of T lymphocytes and the IFN- pathway in enabling breast cancer cells to pass the in vitro BBB. CD8+ cells display the strongest stimulatory effect on breast cancer cell passage. We show that inhibition of the IFN- receptor in MDA-MB-231 breast cancer cells, or neutralization of soluble IFN-, impairs the in vitro trespassing of breast cancer cells. Importantly, we validated our findings using gene expression data of breast cancer patients. CXCL-9,-10,-11/CXCR3 axis, dependent on IFN- signaling activity, was overexpressed in primary breast cancer samples of patients who developed brain metastasis. The data support a role for T-lymphocytes and the IFN- pathway in the formation of brain metastasis of ER- breast cancer, and offer targets to design future therapies for preventing breast cancer cells to cross the BBB.
ARTICLE | doi:10.20944/preprints202305.1853.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: CAR-T; CEA, γδ-T cell; off-the-shelf; GITR signaling
Online: 26 May 2023 (04:45:32 CEST)
CAR-T therapy has achieved considerable treatment success in hematologic tumors by using patient derived autologous αβ T cells. There is an impetus to broaden the applicability of this approach by using a third-party donor derived CAR-T cell product which has a potent anti-tumor function but a constrained GVHD property. In this study, CAR-T cells were prepared from Vγ9Vδ2 T cells expanded by using a novel prodrug PTA and their anti-tumor functions were assessed in conjunction with persistency, localization, and phenotype. γδ T cells were successfully transduced with a CAR specific to CEA with signaling domains of CD3ζ and CD28 (CEA.CAR-γδ T cells), and exhibited potent tumor killing function in vitro. In a xenograft mouse model, CEA.CAR-γδ T cells suppressed CEA+ tumor growth though a limited time window. CEA.CAR-γδ T cells persisted and accumulated in the tumor even after tumor progression, however, ex vivo analysis revealed that those recovered at different time points from PBMC, spleen and tumors gradually lost tumor reactivity as assessed by IFN-γ production. Provision of GITR co-stimulation enhanced anti-tumor function of CEA.CAR-γδ T cells, the result of which imposes additional measurers to be adopted in CAR-γδ T cells for an allogeneic adoptive immunotherapy.
ARTICLE | doi:10.20944/preprints202305.1841.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: antibody-dependent cell-mediated cytotoxicity; ADCC; NK-92 cells; CD16A; CD107a; fucosylation; GA101
Online: 26 May 2023 (04:18:25 CEST)
Antibody-dependent cell-mediated cytotoxicity (ADCC) by natural killer (NK) lymphocytes eliminates cells infected with viruses. Antiviral ADCC requires three components: 1) antibody; 2) effector lymphocytes with the Fc-IgG receptor CD16A; and 3) viral proteins in infected cell membranes. Fc-afucosylated antibodies bind with greater affinity to CD16A than fucosylated antibodies; individuals’ variation in afucosylation contributes to differences in ADCC. Current assays for afucosylated antibodies involve expensive methods. We report an improved bioassay for antibodies that support ADCC which encompasses afucosylation. This assay utilizes externalization of CD107a by NK-92-CD16A cells after antibody recognition. We used anti-CD20 monoclonal antibodies, GA101 WT or glycoengineered (GE), 10% or ~50% afucosylated, and CD20-positive Raji target cells. CD107a increased detection 7-fold compared to flow cytometry to detect Raji-bound antibodies. WT and GE antibody effective concentrations (EC50s) for CD107a externalization differed by 20-fold, with afucosylated GA101-GE more detectable. The EC50s for CD107a-externalization vs. 51Cr cell death were similar for NK-92 CD16A and blood NK cells. Notably, the %CD107a-positive cells negatively correlated with dead Raji cells and was nearly undetectable at high NK:Raji ratios required for cytotoxicity. This bioassay is very sensitive and adaptable to assess anti-viral antibodies but unsuitable as a surrogate assay to monitor cell death after ADCC.
ARTICLE | doi:10.20944/preprints202304.1171.v2
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Tricellular tight junction protein; LSR; RAGE; Bronchial asthma; Titanium dioxide
Online: 25 May 2023 (09:30:03 CEST)
The tricellular tight junction protein angulin-1/lipolysis-stimulated lipoprotein receptor (LSR) is associated with numerous signal transduction pathways that regulate gene expression, epithelial cell function, and morphogenesis. The impacts of particulate matter on LSR and asthma are not known. Therefore, the aim of the present study was to assess the impacts of particulate matter as one of air pollution on LSR expression in asthma. To this end, we investigated the involvement of LSR in the pathogenesis of bronchial asthma in an ovalbumin (OVA) mouse model of asthma exposed to titanium dioxide (TiO2), and examined plasma LSR levels and their relationship with clinical variables in asthma patients and healthy controls. Plasma LSR levels were lower in asthma patients than in healthy controls. Although plasma levels of receptor for advanced glycation end-products (RAGE) were lower in asthma patients than in healthy controls, high mobility group box protein 1 (HMGB1) levels did not differ between these groups. In asthma patients, LSR levels were correlated with the forced vital capacity percentage, ratio of forced expiration (first second)-to-forced vital capacity, white blood cell count, and blood lymphocyte proportion. In mice, LSR expression was significantly decreased in OVA mice compared with control mice, and changed in OVA mice exposed to TiO2. Transforming growth factor beta levels were increased in OVA mice compared with control mice, and changed in OVA mice exposed to TiO2. Overall, plasma LSR levels were decreased in asthma patients, and were influenced by exposure to air pollution. These findings suggest the involvement of LSR in the pathogenesis of asthma.
ARTICLE | doi:10.20944/preprints202305.1747.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Gram +; Gram -; Thymus vulgaris L. essential oil; contact time; bacterial growth
Online: 25 May 2023 (07:10:47 CEST)
Overuse and misuse of antibiotics can pose the risks of spreading mutant strains that show antimicrobial resistance (AMR), with negative impact on management of bacterial infections and economic implications on healthcare systems. Research and development of natural antibacterial agents could be a priority in the next years to improve number of effective antibacterial molecules and to reduce AMR phenomenon and its development. The present study identified the most effective concentration and contact time of Thymus vulgaris L. essential oil (TEO) to obtain bactericidal effect in vitro against different Gram + and Gram – bacterial strains. Six clinically isolated (wild types) bacterial strains, (Citrobacter freundii, Enterococcus feciorum, Proteus mirabilis, Acinetobacter cioffi, Pasteurella putrefaciens, Klebsiella pneumoniae) and two ATCC (Staphylococcus aureus and Streptococcus mutans) were tested after 1min, 3min and 5min of contact with TEO. Preliminary results on S. aureus after 24h incubation revealed a TEO concentration of 9.28mg/mL (w/v) that completely inhibited bacteria growth keeping cell viability. Total suppression of bacterial growth at all tested contact times was observed for all tested bacterial strains and the results were confirmed after 48h incubation. Bacterial growth suppression was confirmed even with presence of organic component. These preliminary results showed in vitro antimicrobial efficacy of TEO against different Gram+ and Gram- bacterial strains. Future studies are necessary to confirm the reproducibility of these results even on other strains and to define exactly the molecular mechanisms of EOs, in order to consider TEO as a valid alternative of classic antibiotic therapies and subsequently to reduce the occurrence of AMR.
ARTICLE | doi:10.20944/preprints202305.1707.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Prevotella copri; Lactobacillus murinus; PSC; inflammation; fibrosis; TGF-β1/Smad path-way
Online: 24 May 2023 (10:32:01 CEST)
Background: primary sclerosing cholangitis (PSC) is a chronic cholestatic disease characterized by inflammation and fibrosis of the bile ducts. Cholestasis may lead to hepatic inflammation and fibrosis, and amelioration of cholestasis may allow recovery from inflammatory and fibrotic pathological damage. Prevotella copri (P. copri) intervention have been reported could significantly improve cholestasis and liver fibrosis in DDC-induced PSC mice model. Despite alone P. copri treatment could not recover DDC-induced inflammation, it increased the abundance of Lactobacillus murinus (L. murinus) compared to DDC treatment, which has been reported to have anti-inflammatory effects. The abundance of L. murinus still not recover to normal level may underlie hepatic inflammation in P. copri+DDC mice. Method: alone or in combination interventions of P. copri and L. murinus were used to investigate the molecular mechanism of improvement of PSC inflammation and fibrosis. Results: P. copri and L. murinus significantly reduced the hepatic inflammatory cell aggregation and inflammatory factor expression, as well as the hepatic collagen content and fibrin factor expression in PSC mice. Further analysis of phosphorylation and dephosphorylation levels revealed that P. copri and L. murinus combined intervention in PSC mice inhibited the activity of DDC-activated TGF-β1/Smad pathway, thereby reducing liver inflammation and fibrosis. Conclusion: combination of P. copri and L. murinus inhibits the TGF-β1/Smad pathway and reduces inflammation and fibrosis in PSC.
REVIEW | doi:10.20944/preprints202305.1682.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: spores; mucosal vaccines; vaccine delivery; Bacillus subtilis; Spore surface display.
Online: 24 May 2023 (04:07:33 CEST)
The development of efficient mucosal vaccines is strongly dependent on the use of appropriate vectors. Various biological systems or synthetic nanoparticles have been proposed to display and deliver antigens to mucosal surfaces. The Bacillus spore, a metabolically quiescent and extremely resistant cell, has also been proposed as a mucosal vaccine delivery system and shown able to conjugate the advantages of live and synthetic systems. Several antigens have been displayed on the spore by either recombinant or non-recombinant approaches, and antigen-specific immune responses have been observed in animals immunized by the oral or nasal route. Here we review the use of the bacterial spore as a mucosal vaccine vehicle focusing on the advantages and drawbacks of using the spore and of the recombinant vs. non-recombinant approach to display antigens on the spore surface. An overview of the immune responses induced by antigen-displaying spores so far tested in animals is presented and discussed.
COMMUNICATION | doi:10.20944/preprints202305.1591.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: SARS-CoV-2; COVID-19; revaccination; virus-neutralization; antigenic cartography
Online: 23 May 2023 (07:18:07 CEST)
Rapid emergence of evasive SARS-CoV-2 variants is an on-going challenge for COVID-19 vaccinology. Traditional virus neutralization tests provide detailed datasets of neutralization titers against the viral variants. Such datasets are difficult to interpret and do not immediately inform on the sufficiency of the breadth of antibody response. Some of these issues could be tackled using the antigenic cartography approach. In this study, we created antigenic maps using neutralization titers of sera from donors who received Sputnik V booster vaccine after primary Sputnik V vaccination and compared them with the antigenic maps based on serum neutralization titers of Comirnaty-boosted donors. Traditional analysis of neutralization titers against WT, Alpha, Beta, Delta, Omicron BA.1 and BA.4/BA.5 showed a significant booster humoral response after both homologous (Sputnik V) and heterologous (Comirnaty) revaccinations against all the studied viral variants. However, despite this, a more in-depth analysis using antigenic cartography revealed that Omicron variants remain antigenically distant from WT, which is indicative of the formation of insufficient levels of cross-neutralizing antibodies. The implications of these findings may be significant when developing a new vaccine regimen.
REVIEW | doi:10.20944/preprints202305.1582.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: NETs; innate immunity; mycobacteria.
Online: 23 May 2023 (05:30:13 CEST)
Mycobacterium tuberculosis complex causes tuberculosis (TB), a disease that causes pulmonary inflammation but can also affect other tissues. Despite macrophages having a defined role in TB immunopathogenesis, other innate immune cells, such as neutrophils, are involved in this process. These cells have high phagocytic ability and a microbial-killing machine comprised of enzymes, antimicrobial peptides, and reactive oxygen species. In the last two decades, a new neutrophil immune response, the neutrophil extracellular traps (NETs), has been intensely researched. NETs comprise DNA associated with histones, enzymes, and antimicrobial peptides. These structures are related to antimicrobial immune response and some immuno-pathogenesis mechanisms. This mini review highlights the role of NETs in tuberculosis and how they can be helpful as a diagnostic tool and/or therapeutic target.
REVIEW | doi:10.20944/preprints202305.1442.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: COVID-19; co-infection; secondary infection; multidrug resistance; alternative strategies
Online: 19 May 2023 (12:02:20 CEST)
Coronavirus disease 2019 (COVID-19) is a potentially serious acute respiratory infection caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Since the World Health Organization (WHO) declared COVID-19 a global pandemic, the virus has spread to more than 200 countries with more than 500 million cases and more than 6 million deaths reported globally. It has long been known that viral respiratory tract infections predispose patients to bacterial infections and that these co-infections often have an unfavourable clinical outcome. Moreover, nosocomial infections, also known as health care-associated infections (HAIs), are those infections that are absent at the time of admission and acquired after hospitalization. However, the impact of coinfections or secondary infections on the progression of COVID-19 disease and its lethal outcome is still debated. The aim of this review was to assess the literature on the incidence of bacterial co-infections and superinfections in patients with COVID-19. The review also highlights the importance of the rational use of antibiotics in patients with COVID-19 and the need to implement antimicrobial stewardship principles to prevent the transmission of drug-resistant organisms in healthcare settings. Finally, alternative antimicrobial agents to counter the emergence of multidrug-resistant bacteria causing healthcare-associated infections in COVID-19 patients will also be discussed.
ARTICLE | doi:10.20944/preprints202305.1424.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: antifungal mechanism; isoespintanol; Candida tropicalis; antibiofilm activity
Online: 19 May 2023 (10:04:23 CEST)
The growing increase in infections caused by C. tropicalis, associated with its drug resistance and consequent high mortality, especially in immunosuppressed people, today generates a serious global public health problem. In the search for new potential drug candidates that can be used as treatments or adjuvants in the control of infections by these pathogenic yeasts, the objective of this research was to evaluate the action of isoespintanol (ISO) against the formation of biofilms fungal, the mitochondrial membrane potential (∆Ψm) and its effect on the integrity of the cell wall. We report the ability of ISO to inhibit the formation of biofilms by up to 89.35%, in all cases higher than the values expressed by amphotericin B (AFB). Flow cytometric experiments using rhodamine 123 (Rh123) showed the ability of ISO to cause mitochondrial dysfunction in these cells. Likewise, experiments using calcofluor white (CFW) and analyzed by flow cytometry, showed the ability of ISO to affect the integrity of the cell wall by stimulating chitin synthesis; these changes in the integrity of the wall were also observed through transmission electron microscopy (TEM). These mechanisms are involved in the antifungal action of this monoterpene.
ARTICLE | doi:10.20944/preprints202305.1380.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antimicrobial resistance (AMR), Antibiotics; Surveillance; India; Taiwan
Online: 19 May 2023 (05:01:35 CEST)
Human exposure to antimicrobial resistance (AMR) through food is now very imperfectly understood, creating a significant gap in the design of interventions. The interchange of AMR genes and the transfer of AMR bacteria from animals to humans through the food chain necessitate comprehensive methods to risk reduction. With a focus on AMR in bacterial species isolated from food products, foods (of both animal and non-animal origin), and ambient samples, the current meta-analysis gathered up-to-date information on the epidemiology of AMR in animal-source food chain. As a result, the combined prevalence of AMR across the various food sources was calculated. From the 18,784 food samples obtained as a result of selected publications, 7,676 (40.9%) samples were contaminated, including 4343 (56.6%) and 3363 (43.4%) samples from Taiwan and India, respectively. Meat (chicken, pork, and beef), fish and milk all have moderate to medium potential for AMR exposure to both Gram-positive and Gram-negative foodborne pathogens such S. aureus, Clostridium, E. coli, Salmonella, etc. Antibiotic resistance to β-lactam, fluoroquinolone, carbapenem etc, is present in the majority of food samples. The results of this study emphasize the persistent danger of antimicrobial residue in animal-derived foods in Taiwan, India, and other nations with comparable customs.
ARTICLE | doi:10.20944/preprints202305.1366.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: regulatory macrophage; arginylglycylaspartic acid; vitamin D3; anti-inflammation; xenotrans-plantation
Online: 19 May 2023 (03:26:46 CEST)
Regulatory macrophages (Mregs) are unique in that they have anti-inflammatory and immunosuppressive properties. Thus, treating inflammatory diseases using Mregs is an area of active research. Human Mregs are usually generated by culturing peripheral blood monocytes stimulated by macrophage colony-stimulating factor with interferon (IFN)-. Here, we generated Mregs with an elongated cell morphology from THP-1 cells stimulated with phorbol 12-myristate 13-acetate and cultured with arginylglycylaspartic acid and vitamin D3. These Mregs regulated macrophage function, and respectively downregulated and upregulated the expression of pro-inflammatory and immunosuppressive mediators. They also expressed Mregs-specific marker, such as dehydrogenase/reductase 9, even when exposed to inflammatory stimulants such as IFN-, lipopolysaccharide, purified xenogeneic antigen, and xenogeneic cells. The Mregs also exerted anti- inflammatory and anticoagulatory actions in response to xenogeneic cells and immunosuppressive effects on mitogen-induced Jurkat T-cell proliferation. Our method of generating functional Mregs in vitro without cytokines is simple and cost-effective.
REVIEW | doi:10.20944/preprints202305.1007.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: dairy microorganisms; SLAB; NSLAB, propionibacteria; minor species; in vivo studies
Online: 15 May 2023 (09:29:41 CEST)
This literature review was aimed to collect investigations on the in vivo evidences for bacteria associated to fermented dairy foods to behave as probiotics with beneficial effects in the prevention and treatment of various diseases. All main bacterial groups commonly present in high numbers in fermented milks or cheeses were taken into account, namely starter lactic acid bacteria (SLAB) Lactobacillus delbrueckii subsp. bulgaricus and lactis, L. helveticus, Lactococcus lactis, Strepto-coccus thermophilus, non starter LAB (NSLAB) Lacticaseibacillus spp., Lactiplantibacillus plantarum, dairy propionibacteria and other less frequently encountered species. Only studies regarding strains of proven dairy origin were considered. Studies in animal models and clinical studies showed that dairy bacteria ameliorate symptoms of inflammatory bowel disease (IBD), mucositis, metabolic syndrome, aging and oxidative stress, cancer, bone diseases, atopic dermatitis, allergies, infections and damages caused by pollutants, mild stress and depression. Immunomodulation and changes in the intestinal microbiota were the mechanisms most often involved in the observed effects. The results of the studies considered indicated that milk and dairy products are a rich source of beneficial bacteria that should be further exploited to the advantage of human and animal health.
REVIEW | doi:10.20944/preprints202305.0976.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: quorum sensing; quorum sensing inhibitors; Chromobacterium violaceum; plant extracts
Online: 15 May 2023 (05:07:34 CEST)
In the new antibiotic era, the exponential increase of multiresistant bacterial strains become the main global health problem. Many researchers focused their efforts to explore novel or combined strategies for combating bacterial resistance. The good knowledge of molecular mechanisms of resistance and bacterial virulence factors as key targets gives us a good scenario to resolve the problem. One particularly attractive and promising way is to attack the main regulatory “network” of bacterial virulence determinants known as Quorum sensing (QS). The inhibition of QS signals will be a novel way for screening more effective Quorum sensing inhibitors (QSIs) and will put a key role in next-generation antimicrobials in the resistance battle. This determined the aim of the present review: comprehensive clarification of the regulatory mechanisms of quorum-sensing signaling pathways in Chromobacterium violaceum and discovery of potential plant quorum sensing inhibitors.
REVIEW | doi:10.20944/preprints202305.0771.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antimicrobial Resistance; Phage engineering; endolysins; phage therapy
Online: 10 May 2023 (15:11:24 CEST)
Antimicrobial resistance (AMR) is a major global concern; antibiotics and other regular treatment methods have failed to overcome the increasing number of infectious diseases. Bacteriophages (phages) are viruses that specifically target/ kill bacterial hosts without affecting other human microbiome. Phage therapy provides optimism in the current global healthcare scenario with a long history of its applications in humans that has now reached various clinical trials. Phages in clinical trials have specific requirements of being exclusively lytic, free from toxic genes with an enhanced host range that adds an advantage to this requisite. This review explains in detail the various phage engineering methods and their potential applications in therapy. To make phages more efficient, engineering has been attempted using techniques like conventional homologous recombination, Bacteriophage Recombineering of Electroporated DNA (BRED), clustered regularly interspaced short palindromic repeats (CRISPR)-Cas, CRISPY-BRED/Bacteriophage Recombineering with Infectious Particles (BRIP), chemically accelerated viral evolution (CAVE), and phage genome rebooting. Phages are administered in cocktail form in combination with antibiotics, vaccines, and purified proteins, such as endolysins. Thus, phage therapy is proving to be a better alternative for treating life-threatening infections, with more specificity and fewer detrimental consequences.
REVIEW | doi:10.20944/preprints202305.0760.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Nanoparticles; virus; bacteria; protein corona; glucocorticoid; innate immunity
Online: 10 May 2023 (14:25:14 CEST)
We advance the notion that much, like artificial nanoparticles, relatively more complex biological entities with nanometric dimensions such as pathogens (viruses, bacteria and other microorganisms) may also acquire a biomolecular corona, upon entering the blood circulation of an organism. We view this biomolecular corona as a component of a much broader non-cellular blood interactome that can be highly specific to the organism, akin to components of the innate immune response to an invading pathogen. We review published supporting data and generalize these notions from artificial nanoparticles to viruses and bacteria. Characterization of the non-cellular blood interactome of an organism may help explain apparent differences in the susceptibility to pathogens among individuals. The non-cellular blood interactome is a candidate therapeutic target to treat infectious and non-infectious conditions.
ARTICLE | doi:10.20944/preprints202305.0747.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: antibodies; bioinformatics; immunoinflammation; Nicotiana tabacum
Online: 10 May 2023 (11:17:21 CEST)
Here, one hundred patients (50 smokers and 50 non-smokers) clinically diagnosed with COVID-19 were studied. Yet, bioinformatics was used to predict epitopes on Tobacco mosaic virus coat protein (TMV-CP) to produce antibodies towards SARS-CoV-2. Death was three times higher in non-smokers than in smokers. However, biochemical parameters did not separate the groups. Bioinformatics analysis predicted the presence of B-cell epitopes in TMV-CP, suggesting the production of antibodies anti-TMV-CP in smoker patients. Smokers may develop severe forms of COVID-19, but survival was superior in the evaluated group than in non-smokers. Anti-TMV-CP antibodies, potentially present in smokers, might act as a pro-immune agent against SARS-CoV-2 at earlier stages of infection. These data are helpful for future studies assessing COVID-19 in smokers.
ARTICLE | doi:10.20944/preprints202305.0615.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Croton; yeast; inhibition; chemical composition and action mechanisms
Online: 9 May 2023 (08:46:49 CEST)
Multiresistant pathogens pose a serious threat to human health. The genus candida is one class of human pathogenic yeasts responsible for infections affecting healthy and immunocompromised patients. In this context, plant essential oils emerged as a future natural alternative to control the diseases caused by these pathogens. Here, it highlighted antimicrobial activity and the mechanisms of action of the essential oil extracted from Croton pluriglandulosus Carn.-Torres & Riina (CpEO) leaves on human pathogenic microorganisms in planktonic and biofilm lifestyles. In addition, for the first time, the oil composition was revealed by GC-MS analysis and the toxicity to human red blood cells (HRBC). Twenty-six chemical compounds were identified in EOCp, Elemicin, Bicyclogermacrene, caryophyllene, brevifolin and 2,4,6-trimethoxy-styrene. Through hemolytic assay, it was shown that CpEO has no toxicity to human RBCs. At the concentration of 50 μg mL-1, CpEO did not show great antibacterial potential. However, promising data were found for C. krusei and C. parapsilosis inhibiting by 89.3% and 80.7% of planktonic cell growth and 83.5% and 77.9% the biofilm formation, respectively. Furthermore, the mechanisms of action CpEO were elucidated by fluorescence. Scanning electron microscopy revealed damage to the cell membrane and pore formation, ROS overproduction, and Induction of apoptosis in candida cells. Our results reinforce the potential of CpEO as an effective alternative molecule of pharmaceutical interest.
ARTICLE | doi:10.20944/preprints202305.0521.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Aircraft; Wastewater; Surveillance; Indicator viruses; Enteric viruses; Respiratory viruses
Online: 8 May 2023 (10:39:58 CEST)
The effective detection of viruses in aircraft wastewater is crucial to establish surveillance programs for monitoring virus spread via aircraft passengers. This study aimed to compare the performance of two virus concentration workflows, adsorption-extraction (AE) and Nanotrap® Microbiome A Particles (NMAP), in detecting the prevalence and concentrations of 15 endogenous viruses in aircraft lavatory wastewater samples. The viruses tested include two indicator viruses, four enteric viruses, and nine respiratory viruses. The results showed that cross-assembly phage (crAssphage), human polyomavirus (HPyV), rhinovirus A (RhV A), and rhinovirus B (RhV B) were detected in all wastewater samples using both workflows. However, enterovirus (EV), human norovirus (HNoV GII), human adenovirus (HAdV), bocavirus (BoV), parechovirus (PeV), epstein-barr virus (EBV), influenza A virus (IAV), and respiratory syncytial virus B (RsV B) were infrequently detected by both workflows, and hepatitis A virus (HAV), influenza B virus (IBV), and respiratory syncytial virus B (RsV A) were not detected in any samples. The NMAP workflow had greater detection rates of EV, PeV, and RsV B than the AE workflow, while the AE workflow had greater detection rates of HAdV, BoV, and EBV than the NMAP workflow. The concentration of each virus was also analyzed, and the results showed that CrAssphage had the highest mean concentration (6.76 log10 GC/12.5 mL) followed by HPyV (5.46 log10 GC/12.5 mL using the AE workflow, while the mean concentrations of enteric and respiratory viruses ranged from 2.48 to 3.63 log10 GC/12.5 mL. Using the NMAP workflow, the mean concentration of crAssphage was 5.18 log10 GC/12.5 mL and the mean concentration of HPyV was 4.20 log10 GC/12.5 mL, while mean concentrations of enteric and respiratory viruses ranged from 2.55 to 3.74 log10 GC/12.5 mL. The mean concentrations of CrAssphage, HPyV, RhV A, and RhV B between the two workflows were statistically significant (p < 0.05). In summary, the present study provides valuable insights into the performance of virus concentration workflows in detecting and quantifying different viruses in aircraft lavatory wastewater samples. The findings can aid in the selection of an appropriate concentration workflow for virus surveillance studies and contribute to the development of efficient and reliable virus detection methods.
REVIEW | doi:10.20944/preprints202305.0492.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: COVID-19; SARS-CoV-2; antiviral; therapeutics; natural products; traditional Chinese medicines; plant extracts
Online: 8 May 2023 (09:34:31 CEST)
Despite the fact that COVID-19 treatment and management are now considerably regulated, SARS-CoV-2 is still one of the leading causes of death in 2022. The availability of COVID-19 vaccines, FDA-approved antivirals, and monoclonal antibodies in low-income countries still poses an issue to be addressed. Natural products, particularly traditional Chinese medicines (TCMs) and medicinal plant extracts (or their active component) have challenged the dominance of drug repurposing and synthetic compound libraries in COVID-19 therapeutics. Abundant resources and excellent antiviral performance make natural products a relatively cheap and easily available alternative for COVID-19 therapeutics. Here, we deliberately review the anti-SARS-CoV-2 mechanisms of the natural products, their potency (pharmacological profiles), and application strategies for COVID-19 intervention. In light of their advantages, this review is intended to acknowledge the potential of natural products as COVID-19 therapeutic candidates.
ARTICLE | doi:10.20944/preprints202305.0305.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Zebrafish; Macrophages; Migration; DUSP2; ERK
Online: 5 May 2023 (05:16:02 CEST)
Dual specificity phosphatase 2 (DUSP2) regulates the activation of members in the mitogen-activated protein kinase (MAPK) family, which is involved in a variety of cellular processes like cell proliferation, differentiation, apoptosis and migration. DUSP2 also regulates the expression of inflammatory mediators in macrophages, however, it remains unknown whether DUSP2 participates in macrophage migration. Here, using the tail fin injury model in zebrafish larvae, we found that deletion of DUSP2 inhibited expression of pro-inflammatory cytokines and macrophage chemokines. Moreover, live imaging results showed that migration of macrophages to the injury site was inhibited after DUSP2 deletion. This inhibitory effect was mediated through reduced activation of extracellular regulated protein kinases (ERK) in DUSP2 knockout zebrafish.
ARTICLE | doi:10.20944/preprints202305.0242.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Chlamydia trachomatis; elementary bodies; human dendritic cells; in vitro; reticulate bodies
Online: 4 May 2023 (08:57:52 CEST)
Chlamydia trachomatis (CT) is an obligate intracellular bacterial pathogen known to cause trachoma, sexually transmitted infections, and reactive arthritis. The more serious sequelae of these diseases, blindness from trachoma and pelvic inflammatory disease from chlamydial STD are immunopathological responses to chronic infections. With the abundance of dendritic cells in CT infection sites and their central importance in immune regulation, the susceptibility of dendritic cells to CT infection was investigated in vitro. CT (serovar F) was grown and extracted from HeLa 229 cells for infection of human dendritic cells (DCs). Human DCs were generated from peripheral blood mononuclear cells in the presence of GM-CSF and IL-4. Infected DCs were harvested at 0, 4, 24, and 48 h after infection and immunostained. Results from fluorescence microscopy showed that DC can be infected and can support the growth of CT in vitro. Intracellular elementary and reticulate bodies of CT were detected, and reticulate bodies were shown to multiply over the 48 h-cycle in DC. At 48 h, intracellular elementary bodies were detected in some DCs. These results may provide new insights into the possible participation of DC in sustaining chronic or latent infection, or even dissemination of CT infection to other sites.
ARTICLE | doi:10.20944/preprints202305.0163.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: EBER1; Intracellular transport; RPL22; Secretion; Structure
Online: 4 May 2023 (02:48:03 CEST)
Epstein-Barr virus (EBV)-encoded RNAs (EBERs) are structurally conserved small, noncoding RNAs constitutively expressed in EBV infection. Although primarily localised in the nucleus, EBERs are found in the cytoplasm and exosomes. However, the mechanism(s) of EBERs transport is not known. This study aimed to investigate the structural impact of EBER1 on its transport. EBER1 stem-loop (SL) deletion mutants (ΔSL1, ΔSL3 and ΔSL4) were created and stably transfected into HEK293T cells. The expression of EBER1 was quantified in total cell, nuclear, cytoplasmic and exosomal fractions. The quantification was performed in the presence of physiological expression of RPL22 and La, and after silencing them. These proteins are believed to be involved in EBER1 transport and secretion. Compared to the wildtype EBER1 transfectants, the expression level of EBER1 gene in all mutants was significantly lower in the total cell, cytoplasmic and exosomal fractions. However, ΔSL3 mutant showed significant nuclear retention. Silencing RPL22 resulted in increased nuclear-cytoplasmic trafficking of EBER1. Silencing La protein did not affect EBER1 secretion. Alternatively, the store-operated intracellular Ca2+ was found to correlate with EBER1 expression in exosomes. Taken together, EBER1 structure and its interaction with RPL22 appeared to be important in the nuclear-cytoplasmic transport of the RNA.
ARTICLE | doi:10.20944/preprints202305.0132.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: HIV; dopamine; latency reversal; methamphetamine; macrophages; substance use
Online: 3 May 2023 (10:36:07 CEST)
There is a significant overlap between HIV infection and substance use disorders. Dopamine (DA) is the most abundantly upregulated neurotransmitter in Methamphetamine abuse, with receptors (DRD1-5) that are expressed by neurons as well as by a large diversity of cell types, including innate immune cells that are targets of HIV infection, making them responsive to the hyperdopaminergic environment that is characteristic of stimulant drugs. Therefore, the presence of high levels of dopamine may affect the pathogenesis of HIV, particularly in the brain. The stimulation of HIV-latently infected U1 promonocytes with DA significantly increased viral p24 levels in the supernatant at 24 hrs, suggesting effects on activation and replication. Using selective agonists to different DRDs, we found that DRD1 played a major role in activating viral transcription, followed by DRD4, which increased p24 with a slower kinetic. Transcriptome and systems biology analyses led to the identification of a cluster of genes responsive to DA, where S100A8 and S100A9 were most significantly correlated with the early increase of p24 levels following DA stimulation. Conversely, DA increased the expression of these genes’ transcripts at the protein level, respectively MRP8 and MRP14, which form a complex also known as Calprotectin. Interestingly, MRP8/14 was able to stimulate HIV transcription in latent U1 cells, and this occurred via binding to the receptor for advanced glycosylation end-product (RAGE). Using selective agonists, both DRD1 and DRD4 increased MRP8/14 on the surface and in the cytoplasm, as well as secreted in the supernatants. On the other hand, while DRD1/5 did not affect the expression of RAGE, DRD4 stimulation caused its downregulation, offering a mechanistic for the delayed effect via DRD4 on p24 increase. To cross-validate MRP8/14 as a DA signature with biomarker value, we tested its expression in HIV+ Meth users’ brains and peripheral cells. MRP8/14+ cells were more frequently identified in mesolimbic areas such as basal ganglia of HIV+ Meth+ cases compared to HIV+ non-Meth users or to controls. Likewise, MRP8/14+ CD11b+ monocytes were more frequent in HIV+ Meth users, particularly in participants with detectable viral load in the CSF. Overall, our results suggest that the MRP8 and MRP14 complex may serve as a signature to distinguish subjects using addictive substances in the context of HIV, and that this may play a role in aggravating HIV pathology by promoting viral replication in people with HIV who use Meth.
ARTICLE | doi:10.20944/preprints202305.0106.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Human norovirus; RNA-dependent RNA polymerase (RdRp) region; VP1 gene; epitope mapping; molecular evolution
Online: 3 May 2023 (07:27:28 CEST)
To understand the evolution of the human norovirus GII.P6-GII.6 and GII.P7-GII.6 strains, we analyzed both the RdRp region and VP1 gene in globally collected strains using authentic bioinformatics technologies. A common ancestor of the P6- and P7-type RdRp region emerged approximately 50 years ago and a common ancestor of the P6- and P7-type VP1 gene emerged approximately 110 years ago. Subsequently, the RdRp region and VP1 gene evolved. Moreover, the evolutionary rates were significantly faster for the P6-type RdRp region and VP1 gene than the P7-type RdRp region and VP1 genes. Large genetic divergence was observed in the P7-type RdRp region and VP1 gene compared with the P6-type RdRp region and VP1 gene. The phylodynamics of the RdRp region and VP1 gene fluctuated after the year 2000. Positive selection sites in VP1 proteins were located in the antigenicity-related protruding 2 domain, and these sites overlapped with conformational epitopes. These results suggest that the GII.6 VP1 gene and VP1 proteins evolved uniquely due to recombination between the P6- and P7-type RdRp regions in the HuNoV GII.P6-GII.6 and GII.P7-GII.6 virus strains.
ARTICLE | doi:10.20944/preprints202305.0068.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: ESBLs; CTX-M; E. coli; Children; Cameroon
Online: 2 May 2023 (07:37:53 CEST)
Extended-spectrum β-lactamase (ESBL) mediating resistance in Enterobacterales is a global public health issue, especially in low-and middle-income countries (LMICs) such as Cameroon. ESBL-producing Enterobacterales reduce therapeutic options and lead to the use of last resort drugs such as carbapenems even in vulnerable populations like children under five years. This study aims at determining the phenotypic and genotypic characteristics of ESBL-producing Escherichia coli (ESBL-Ec) isolated from children under five years with and without diarrhoea in two health care facilities in Dschang. A cross-sectional study was conducted from 3 February to 19 May 2022 in two hospitals in the city of Dschang, Cameroon. Stool collected were cultured on Eosine Methylen Blue (EMB) medium. Enterosystem 18 R kit was used for bacterial identification. Evaluation of the resistance patterns and detection of ESBL production were performed with, the Kirby Bauer disk diffusion method and CHROMagar® ESBL medium, respectively. The genomic DNA of ESBL-Ec was extracted using the boiling method and subjected to conventional and multiplex PCRs for detection of blaSHV, blaCTX-M and blaTEM genes. Data were entered into ExcelTM 2016. Epi info and R software were used for statistical analyses with a p-value <0.05 considered statistically significant. Out of the 125 children enrolled, 67.2% (84/125) were colonized by E. coli. Among these, 57.14% (48/84) were colonized by ESBL-Ec. ESBL- Ec isolates showed high levels of resistance to amoxicillin-clavulanic acid (96.22%), cefotaxime (75.47%), ceftriaxone (73.58%), ofloxacin (67.92%), levofloxacin (56.6%) and ciprofloxacin (54.71%). Children aged between 1-3 years (47.62%, p=0.09) and those who had taken an antibiotic one week prior to collection (70.83%, p=0.04) had a higher prevalence of ESBL-Ec with statistical significance. The majority of ESBL-Ec isolates (52.83%; 28/53) were co-producers of blaCTX-M and blaTEM. Infection prevention and control measures coupled with antimicrobial stewardship strategies need to be strengthened to reduce emergence and dissemination of ESBL-Ec among this vulnerable population.
ARTICLE | doi:10.20944/preprints202305.0021.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: pneumococcal disease; serotype; geographic differentiation; vaccination; temporal variation; recombination
Online: 1 May 2023 (10:15:32 CEST)
Streptococcus pneumoniae is the major cause of invasive pneumococcal disease (IPD). Since 1998, multilocus sequence typing (MLST) has been used for identifying the genotypes of strains of S. pneumoniae and helped reveal a diversity of local and regional epidemiological patterns for IPD, resulting in an archived MLST dataset of over 74,000 isolates. However, the global patterns of MLST sequence type (ST) and allele type (AT) distributions remain largely unexplored. In this study, we investigated the spatial and temporal patterns of AT and ST distributions of S. pneumoniae. We extracted S. pneumoniae MLST data from PubMLST.org and conducted various population genetic and phylogenetic analyses. Our analyses demonstrated both shared and unique distributions of STs and ATs among continental and national/regional populations. Among the 17915 STs in the dataset, 36 STs representing 15263 isolates were broadly shared among all six continents, consistent with recent gene flow and clonal dispersal of this pathogen. The analysis of molecular variance revealed that >96% genetic variations were found within individual continental and national/regional populations. However, though low (<4%), statistically significant genetic differentiation among continental and national populations were observed. Comparisons between non-clone-corrected and clone-corrected datasets showed that localized clonal expansion contributed significantly to the observed genetic differentiations among continents and countries/regions. Temporal analyses of the isolates showed that implementation of pneumococcal conjugate vaccine impacted the distributions of STs. Linkage disequilibrium analyses identified evidence for non-random recombination in all continental populations of this species. We discussed the implications of our analyses to the global epidemiology and future vaccine developments for S. pneumoniae.
REVIEW | doi:10.20944/preprints202304.1233.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Mycobacterium tuberculosis; tuberculosis; drug-resistance; drug combinations; drug-tolerance; persisters; differentially detectable cells; mice models; tuberculosis therapy; clinical trials
Online: 29 April 2023 (09:54:07 CEST)
The lungs of tuberculosis (TB) patients contain a spectrum of granulomatous lesions ranging from solid and well vascularized cellular granulomas, to avascular caseous granulomas. In solid granulomas, current therapy kills actively replicating (AR) intracellular bacilli, while in low vascularized caseous granulomas the low oxygen tension stimulates aerobic and microaerophilic AR bacilli to transit into non-replicating (NR), drug-tolerant, extracellular stages. These stages, which do not have genetic mutations and are often referred to as persisters, are difficult to eradicate due to low drug penetration inside caseum and mycobacterial cell walls. The sputum of TB patients contains also viable bacilli called differentially detectable (DD) cells that, unlike persisters, grow in liquid, but not in solid media. This review provides a comprehensive update on drug combinations killing in vitro AR and drug-tolerant bacilli (persisters and DD cells), and sterilizing Mycobacterium tuberculosis-infected BALB/c and caseum-forming C3HeB/FeJ mice. These observations have been important for testing new drug combinations in noninferiority clinical trials, in order to shorten duration of current regimens against TB. In 2022, the World Health Organization, based on one of this trial, supported the use of a 4-month regimen for treatment of drug-susceptible TB as a possible alternative to the current 6-month regimen.
ARTICLE | doi:10.20944/preprints202304.1216.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: contamination; CFU/ml; biocide; microorganisms
Online: 29 April 2023 (05:36:38 CEST)
The proliferation of bacteria in fresh water-based paints is a concerning issue, as these microorganisms can utilize the organic materials in paint as a source of carbon to stimulate their growth, leading to the deterioration of painted surfaces. This study analyzed the bacterial quality and lead concentration of six paint samples collected from a manufacturing industry in Lagos. The total bacterial population monitored in the paint samples ranged from 1×106 CFU/ml to 7.8×109 CFU/ml, and while the population density decreased in all the samples throughout the 3-month study period, it was not uniform. The observed decrease in population density may be attributed to the biocide present in the paint samples and environmental factors such as heavy metal concentration. Interestingly, Pseudomonas oleovorans, P. luteola, Burkholderia cepacia, Sphingomonas paucimobilis, and Stenotrophomonas maltophilia were still able to grow in the paint samples from week 0 to week 10. The study highlights the potential for bacterial contamination of water-based paint, and the need for manufacturers to take measures to prevent this. The findings suggest that even fresh paint can serve as a substrate for bacterial growth, which can lead to issues such as loss of viscosity, discoloration, and malodor. Additionally, the presence of bacteria in paint can lead to degradation of painted surfaces, which can have economic and public health implications. The study emphasizes the importance of incorporating effective biocides in paint formulations, as well as communicating proper storage conditions to retailers, to help increase the shelf-life of paint and prevent bacterial contamination. Overall, the study provides important insights into the potential risks associated with bacterial contamination of paint and the need for proactive measures to prevent it.
ARTICLE | doi:10.20944/preprints202304.1111.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: viruses; SARS-CoV-2; Raman spectroscopy; magnetic beads; sample preparation
Online: 28 April 2023 (04:46:10 CEST)
We introduce a magnetic bead-based sample preparation scheme for enabling a Raman spectroscopic differentiation of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) positive and negative samples. The beads were functionalized with the angiotensin-converting enzyme 2 (ACE2) receptor protein, which is used as recognition element to selectively enrich SARS-CoV-2 on the surface of the magnetic beads. Subsequent Raman measurements directly enable discriminating SARS-CoV-2 positive and negative samples. The proposed approach is applicable for other virus species, too, when the specific recognition element is exchanged. Series of Raman spectra were measured on three types of samples, namely SARS-CoV-2, Influenza A H1N1 virus and a negative control. For each sample type, eight independent replicates were considered. All spectra are dominated by the magnetic bead substrate and no obvious differences between sample types are apparent. In order to address the subtle differences in the spectra, we calculated different correlation coefficients, namely the Pearson coefficient and the Normalized Cross Correlation coefficient. By comparing the correlation with the negative control differentiating between SARS-CoV-2 and Influenza A virus is possible. This study provides a first step towards the detection and potential classification of different viruses with the use of conventional Raman spectroscopy.
ARTICLE | doi:10.20944/preprints202304.1091.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antigen; COVID-19 vaccination; machine learning
Online: 28 April 2023 (03:23:48 CEST)
Vaccines trigger a complicated immunological response that includes B and T cells, with B cells producing antibodies. SARS-CoV-2 immunity weakens over time after vaccination. Discovering key changes in antigen-reactive antibodies over time after vaccination could help improve vaccine efficiency. In this study, we collected data on blood antibody levels in a cohort of healthcare workers vaccinated for COVID-19 and obtained 73 antigens in samples from four groups according to the duration after vaccination, including 104 unvaccinated healthcare workers, 534 healthcare workers within 60 days after vaccination, 594 healthcare workers between 60 and 180 days after vaccination, and 141 healthcare workers over 180 days after vaccination. An efficient machine learning based framework containing four feature selection methods (least absolute shrinkage and selection operator, light gradient boosting machine, Monte Carlo feature selection, and maximum relevance minimum redundancy) and four classification algorithms (decision tree, k-nearest neighbor, random forest, and support vector machine) was designed to screen out essential antigens. Several efficient classifiers with weighted F1 value around 0.75 were constructed. This study revealed that S1+S2, S1.mFcTag, S1.HisTag, S1, S2, Spike.RBD.His.Bac, Spike.RBD.rFc, and S1.RBD.mFc were most highly ranked among all features, where S1 and S2 are the subunits of Spike, and the suffixes represent the tagging information of different recombinant proteins. Meanwhile, the classification rules were extracted from the optimal decision tree to explain quantitatively the roles of antigens in the classification. This study identified antibodies associated with decreased clinical immunity based on populations with different time spans after vaccination. These antibodies have important implications for maintaining long-term immunity to SARS-CoV-2.
ARTICLE | doi:10.20944/preprints202304.1090.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Invasive lobular cancer; pleomorphic invasive lobular cancer; tumor-infiltrating lymphocytes; programmed cell death 1; programmed cell death ligand 1; 22C3 assay; SP142 assay; survival
Online: 28 April 2023 (03:22:03 CEST)
Background: The prognostic and predictive role of stromal tumor-infiltrating lymphocytes (sTILs) is undetermined in pleomorphic invasive lobular cancer (pILC). The same applies for the expression of PD-1/PD-L1 in this rare breast cancer subtype. Here, we aimed to investigate the expression of sTILs, and analyze the PD-L1 expression levels in pILC. Methods: Archival tissues from sixty-six patients with pILC were collected. The sTIL density was scored as a percentage of tumor area, using the following cut-offs: 0%; <5%; 5-9%; and 10-50%. PD-L1 expression was analyzed using IHC on formalin-fixed, paraffin-embedded tissue sections, using the SP142 and 22C3 antibodies. Results: 82% of the sixty-six patients were hormone receptor-positive; 8% of cases were triple negative (TN), while 10% showed human epidermal growth factor receptor 2 (HER2) amplification. sTILs were present in 64% (1%) of the study population. Using the SP142 antibody, 36% of tumors demonstrated a positive PD-L1 score of 1%, and 28% had a positive PD-L1 score of 1 using the 22C3 antibody. There was no correlation of sTILs or PD-L1 expression with tumor size, tumor grade, nodal status, expression of estrogen receptor (ER) or amplification of HER2. Our data did not show any difference in survival between the three molecular subtypes of pILC with respect to sTILs and PD-L1 expression. Conclusion: This study shows that pILCs show some degree of sTILs and PD-L1 expression, however this was not associated with survival benefit. Additional large trials are needed to understand the immune infiltration in lobular cancer, even more in the pleomorphic subtype.
REVIEW | doi:10.20944/preprints202304.1082.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: bacterial spores; spore display system technology; mucosal vaccine; spore engineering; Bacillus subtilis
Online: 27 April 2023 (15:31:29 CEST)
Mucosal vaccines offer several advantages over injectable conventional vaccines, such as adaptive immunity induction, secretory IgA production at the entry site of most pathogens, and needleless vaccinations. Despite their potential, only a few mucosal vaccines are currently used. Developing new effective mucosal vaccines strongly relies on identifying innovative anti-gens, efficient adjuvants, and delivery systems. Several approaches based on phages, bacteria, or nanoparticles have been proposed to deliver antigens to mucosal surfaces. Bacterial spores have also been considered antigen vehicles, and various antigens have been successfully exposed on their surface. Due to their peculiar structure, the spores conjugate the advantages of live microorganisms with synthetic nanoparticles. When mucosally administered, spores expressing anti-gens have been shown to induce antigen-specific, protective immune responses. This review accounts for recent progress in the formulation of spore-based mucosal vaccines, describing the spore's structure, specifically the spore surface, and the diverse approaches developed to improve its efficiency as a vehicle for heterologous antigen presentation.
REVIEW | doi:10.20944/preprints202303.0477.v3
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: H5N1; Influenza A; first-line immunity; interferon; mucosal antibodies; immune evasion; sialic acid receptor; natural lymphocytes; adaptive lymphocytes; monocytes; macrophages; cytokines
Online: 27 April 2023 (02:56:58 CEST)
The Influenza A Virus (IAV) represents an enveloped, positive-sense and single-stranded RNA-based virus that infects mammals mainly via the respiratory system, although other bodily systems are also infected and undergo various extents of inflammatory pathogenesis. There are two well-known strains of IAV that cause life-threatening disease in mammals; H1N1 and H5N1, and the first strain caused the 1918 IAV H1N1 pandemic that claimed between 30 and 50 million human lives. Due to the significant ability of IAV to evade important immune recognition, the virus was observed to favor the onset of secondary microbial infections (i.e. bacterial or fungal), as the overall performance of the immune system became transiently weakened during the viral infection. During the IAV H1N1 pandemic, many patients died as a result of bacterial pneumonia, as pathogenic bacteria, such as Streptococcus pneumoniae and Haemophilus influenzae, gained a wider opportunity to colonize and infect vital areas of the lower respiratory tract, and such a phenomenon led to the excessive, prophylactic usage of antibiotics due to the increased levels of panic, which in turn favored the natural selection of bacteria with genes that became resistant to such antibiotics. Antibiotics might be required for usage solely when bacteria are known to be colonizing vital areas of the human body, and this aspect is tricky, as colonization is asymptomatic and screening is consequently rare. Recently, new variants of the avian IAV H5N1 strain were transmitted from live, infected birds to mammals, including humans in some isolated cases, and given that there have already been several zoonotic spillover events overall since the beginning of 2023, we are rapidly approaching the time when a zoonotic spillover into humans will mark the first epidemic outbreak of the avian flu in humans. A lethality rate of 60% was projected by the World Health Organization, as the virus was shown to favor the development of life-threatening hyper-inflammatory responses at the levels of alveolar tissues constituted by Type II pneumocytes. There are hints that novel variants of H5N1 are capable of infecting the intestinal layer, as recently, two dolphins died as a result of ingesting infected birds within the area of the British Isles. IAV is known to suppress the production and transmission of Type I Interferons by expressing various non-structural proteins (NSPs), such as NSP1, which was found to be also packaged into exosomes and transmitted to neighboring uninfected cells, thereby preventing them from responding to the virus in the first place. A more pronounced rate of innate immune evasion would probably be observed in H5N1 IAV infection than in the infection caused by recent variants of H1N1 IAV. The H5N1 strain of IAV was also found to secrete a higher concentration of NSP1 than SARS-CoV-2, indicating the existence of an association to the greater mortality rate of H5N1 IAV infection. A direct, prophylactic stimulation of the interferon system using a reduced oral or nasal dosage of recombinant anti-inflammatory and anti-viral interferon glycoproteins may represent the most viable approach to prevent an emergence of a life-threatening H5N1 IAV pandemic. A similar non-invasive approach could be developed for an Marburg Virus (MARV) and a Nipah Virus (NiV) infection of humans, as risks of the emergence of a Marburg epidemic and also of a Nipah epidemic may be substantial at this stage as well. Clinical testing of clinical approaches as such could be of critical importance at the moment. Animals could also benefit from related clinical approaches. Somatic natural and adaptive lymphocytes treated with IFN I and III could also constitute a substantial approach of immunization and heavily favor an indefinite shift in the evolutionary battle between the host organism and microbes of public health concern.
ARTICLE | doi:10.20944/preprints202304.0961.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: COVID-19 patient; whole Genome sequence; Of SARS-COV-2; phylogenetic analysis and Transmission supported
Online: 26 April 2023 (05:15:36 CEST)
Abstract The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in people in the city of Wuhan at the end of December 2019, and it has since spread to all continents. Global interest has been focused on discovering a treatment and developing a successful coronavirus vaccine as a result of the emergence of this new coronavirus. In this research, we sequenced the whole genome of the SARS-COV-2 virus that were isolated from 40 patients in Duhok, Iraq. 95 different mutations were identified in our isolation when such the whole genome sequence of the SARS-COV-2 isolated from the city of Wuhan, China (Accession number: NC 045512.2) was matched to the virus's sequence using Sequencing technology (Illumina , USA ) and Assembly method (iVar 1.3.1). Sequence analysis revealed that 38 mutations were found at spike glycoprotein (S), 30 of which were found in the ORF1b , 11 mutations were found in ORF1b ,7,3,2,1 mutations were found in ( N,M,ORF6 ,ORF9 /E ) genes which had been linked to structural changes at various places. The conclusion that the cases in Iraq were of different origins of infections and had a close relationship with the isolates from different country and state were further confirmed by phylogenetic analysis and transmission. The whole genome sequence of the SARS-CoV-2 , which were identified from the Iraqi Kurdistan region, and reported as a first study in Kurdistan region.
REVIEW | doi:10.20944/preprints202304.0928.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Neutrophils; Tumor associated neutrophils; neutrophil derived exosomes; immune suppression; metastasis; tumor microenvironment; Neutrophil extracellular trap; Trogocytosis; ADCC and ADCP
Online: 25 April 2023 (13:36:01 CEST)
Neutrophils are the most abundant immune cells and make up about 70% of white blood cells in human blood and play a critical role as the first line of defense in the innate immune response. They also help regulate the inflammatory environment to promote tissue repair. However, in cancer, neutrophils can be manipulated by tumors to either promote or hinder tumor growth depending on the cytokine pool. Studies have shown that tumor-bearing mice have increased levels of neutrophils in peripheral circulation, and that neutrophil-derived exosomes can deliver various cargos, including lncRNA and miRNA, which contribute to tumor growth and degradation of extracellular matrix. Exosomes derived from immune cells generally possess anti-tumor activities and induce tumor-cell apoptosis by delivering cytotoxic proteins, ROS generation, H2O2 or activation of Fas-mediated apoptosis in target cells. Engineered exosome-like nanovesicles have been developed to deliver chemotherapeutic drugs precisely to tumor cells. However, tumor-derived exosomes can aggravate cancer-associated thrombosis through the formation of neutrophil extracellular traps. Despite the advancements in neutrophil-related research, a detailed understanding of tumor-neutrophil crosstalk is still lacking and remains a major barrier in developing neutrophil-based or targeted therapy. This review will focus on the communication pathways between tumors and neutrophils, and the role of neutrophil-derived exosomes (NDEs) in tumor growth. Additionally, potential strategies to manipulate NDEs for therapeutic purposes will be discussed.
ARTICLE | doi:10.20944/preprints202304.0914.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Metformin; Quorum sensing; Quorum quenching; Pseudomonas aeruginosa; Virulence; Drug repurposing; Anti-virulence therapy; Biofilm inhibition
Online: 25 April 2023 (09:54:20 CEST)
Metformin (MeT) is an FDA-approved drug with a myriad of health benefits. Besides being used as an anti-diabetic drug, MeT is also effective against various cancers, liver-, cardiovascular-, and renal diseases. It has also been proven to demonstrate anti-ageing and neuroprotective effects. This study was undertaken to examine its unique potential as an anti-virulence drug against an opportunistic bacterial pathogen, Pseudomonas aeruginosa. Due to the menace of multidrug resistance in pathogenic microorganisms, many novel or repurposed drugs with anti-virulence prospects are emerging as next-generation therapies with the aim to overshadow the application of existing antimicrobial regimens. The quorum sensing (QS) mechanisms of P. aeruginosa are an attractive drug target for attenuating bacterial virulence. In this context, the anti-QS potential of MeT was scrutinized using biosensor assays. MeT was comprehensively evaluated for its effects on different motility phenotypes, virulence factor production (phenotypic and genotypic expression) along with biofilm development in P. aeruginosa in vitro. At sub-lethal concentrations, MeT displayed prolific quorum quenching (QQ) ability and remarkably inhibited AHL biosynthesis in P. aeruginosa. Moreover, MeT (1/8 MIC) effectively downregulated the expression levels of various QS- and virulence genes in P. aeruginosa, which coincided with a notable reduction in the levels of alginate, hemolysin, pyocyanin, pyochelin, elastase, and protease production. In silico analysis through molecular docking also predicted strong associations between the QS receptors of P. aeruginosa and MeT. MeT also compromised the motility phenotypes and successfully abrogated biofilm formation by inhibiting EPS production in P. aeruginosa. Hence, the QQ, anti-virulence, and anti-fouling potential of MeT was elucidated for the first time against P. aeruginosa.
REVIEW | doi:10.20944/preprints202304.0807.v2
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: rabies; RABV; PRV; single-stranded RNA; RNA-dependent RNA Polymerase; viral self-camouflaging; glycoprotein; innate immunity; interferon system; natural lymphocytes; adaptive immunity; adaptive lymphocytes; IgA; IgM; IgG; primary dendritic cells; macrophages
Online: 25 April 2023 (07:38:14 CEST)
Despite being a rare disease worldwide, rabies has the highest morbidity and mortality rates, with roughly 99% of symptomatic cases leading to coma and death. Rabies represents an infectious disease caused by the Rabies virus (RABV), which is part of the Lyssavirus group and the Rhabdoviridae family, and it mainly spreads through the bite and scratch of an infected mammal, but particularly of wild animals, such as bats, foxes, wolves and racoons, and of domestic animals, such as dogs and cats, in rabies-prone areas of the world. Airborne transmission has been deemed as extremely rare, and no clinical case as such has been recorded worldwide yet, except in the enclosed environment, such as research laboratories and caves where infected bats are present. Domestic mammals, such as dogs and ferrets, represent other important reservoirs of disease transmission, and the human cases of Asia and Africa amount approximately 95% of all human cases worldwide. Infected animals most commonly start transmitting the virus once the first symptoms have occurred, and if they experience disease aggravation and death within 10 days, a case of rabies is registered, more easily if the incidence occurred in the urban area and then, any person or animal that had been potentially exposed are strongly recommended to receive the inoculation. It is rare for asymptomatic mammals to transmit the illness. Most First-World and several Second-World countries have recently been declared dog rabies-free by the World Health Organization. The disease can only be treated prophylactically, with three doses of a vaccine containing an inactivated form of RABV, or with five doses of the vaccine and two doses of anti-RABV immunoglobulins within 28 days if the patient is believed to have been exposed to the virus beforehand. It has been projected that, once the viral load reaches elements of the central nervous system, prophylactic approaches are no longer effective, even if symptoms have not begun yet, and this highlights the urgent trait of the medical condition, strongly recommending exposed people to receive the prophylactic doses immediately after the potential exposure to the virus. The pathogen first infects the bodily fluids, before reaching the peripheral nervous system, from where it will gradually move toward the spinal cord or the encephalon, at a speed of movement ranging from 1 to 40 cm per day. It was also found, in extremely rare circumstances, to infect the nasopharyngeal cavity and the lungs. The primary cause of a successful, gradual advance of the viral load toward the point of clinical no-return for the patient - the CNS - is a complex mechanism of induced innate immune evasion, with the interferon system being heavily targeted and silenced by RABV proteins. The ‘Milwaukee’ protocol is locally believed to decrease the mortality rate of the clinical illness to approximately 80%, although significantly more research is required in this sense. First-line immune evasion represents the central mechanism developed by viruses during their evolutionary process to gain control over human immunity, so it could be the development and adjustment of a counter-offensive to this evolutionary operating system that could address the core elements of the problem. Human recombinant Type I and Type III Interferons were found to be significant vaccine adjuvants and to considerably delay the clinical onset of the disease. Despite their central role in natural immunity-based prophylaxis, vaccine support and, in often cases, vaccination per se, a local administration of IFNs as such may not be enough to tackle the core problem of the endemic disease, and a specific and systemic treatment of potential host cells with IFN I and III, as well as IFN-stimulating proteins, may constitute a major research requirement in the coming years of disease investigation, as the inoculation efforts with the inactivated virus and immunoglobulin administration continue. The administration of a relatively low dosage of somatic Natural Killer cells, gamma-interferon and perhaps, of somatic helper CD4+ and somatic cytotoxic CD8+ T-lymphocytes treated with alpha-, beta- and lambda-interferon could be merged with the administration of a similar dosage of alpha-, beta- and lambda-interferon during the efforts to develop an effective and less costly prophylactic vaccine against rabies. A combination of a nasal substance containing a low dosage of IFN I and III with a reduced concentration of neutralized RABV copies, and/or with a low dose of anti-RABV IgA antibodies, could also be tested for humans for the purposes of pre- and post-exposure prophylaxis.
ARTICLE | doi:10.20944/preprints202304.0834.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antifungal agent; in vitro susceptibility; oral Candida; nystatin; fluconazole; caspofungin
Online: 24 April 2023 (07:49:36 CEST)
The carriage of Candida albicans in children's oral cavities is associated with a higher risk for early childhood caries, so controlling this fungus in early life is essential for preventing caries. In a prospective cohort of 41 mothers and their children from 0-2 years of age, this study addressed 4 main objectives: 1) Evaluate in vitro the antifungal agent susceptibility of oral Candida isolates from the mother-child cohort, 2) Compare Candida susceptibility between isolates from the mothers and children; 3) Assess longitudinal changes in the susceptibility of the isolates collected between 0-2 years; and 4) Detect mutations in C. albicans antifungal resistance genes. Susceptibility to antifungal medications was tested by in vitro broth microdilution and expressed as minimal inhibitory concentration (MIC). C. albicans clinical isolates were sequenced by whole genome sequencing, and the genes related to antifungal resistance, ERG3, ERG11, CDR1, CDR2, MDR1, and FKS1, were assessed. Four Candida spp (n=126) were isolated: C. albicans, C. parapsilosis, C. dubliniensis, and C. lusitaniae. Caspofungin was the most active drug for oral Candida, followed by fluconazole and nystatin. Two missense mutations in the CDR2 gene were shared among C. albicans isolates resistant to nystatin. Most of the children’s C. albicans isolates had MIC values similar to those from their mothers, and 70% remained stable to antifungal medications from 0-2 years. For caspofungin, 29% of the children’s isolates showed an increase in MIC values from 0-2 years. Results of the longitudinal cohort indicated that clinically used oral nystatin was ineffective in reducing the carriage of C. albicans in children; novel antifungal regimens in infants are needed for better oral yeast control.
REVIEW | doi:10.20944/preprints202304.0591.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: antibiotics; antibiotic resistance; multidrug resistance genes; molecular mechanisms
Online: 19 April 2023 (10:54:50 CEST)
Antibiotic resistance among bacterial pathogens is recognized as a major threat to human health worldwide. The emergence of multidrug-resistant bacteria can also be found in the community settings, apart from hospital environment, which indicates that reservoirs of antibiotic resistance genes do exist outside the hospital. The growth of antibiotic resistance is a consequence of bacterial adaptations in response to selective pressures. To survive in this hostile environment, bacteria develop defence mechanisms such as chemical modification of antibiotics, enzyme-catalysed antibiotic degradation, altered permeability, antibiotic efflux, mutation of target sites and biofilm formation, resulting in resistance to nearly all currently available antibiotics used in the clinical practice. The present review summarizes insights into the molecular mechanisms underlying the antibiotic resistance which is useful for planning strategies to combat antibiotic resistance and devise innovative therapeutic tools to fight against multidrug-resistant bacterial species.
REVIEW | doi:10.20944/preprints202304.0555.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Gastric Cancer; Helicobacter pylori; cag Pathogenicity Island; Cytotoxin-Associated Gene A; Oncoprotein; Vacuolating Toxin A; Immune Evasion
Online: 19 April 2023 (07:14:39 CEST)
Gastric cancer is a challenging public health concern worldwide and remains a leading cause of cancer-related mortality. The primary risk factor implicated in gastric cancer development is infection with Helicobacter pylori. H. pylori induces chronic inflammation affecting the gastric epithelium, which can lead to DNA damage and promotion of precancerous lesions. Disease manifestations associated with H. pylori are attributed to virulence factors with multiple activities and its capacity to subvert host immunity. One of the most significant H. pylori virulence determinants is the cagPAI gene cluster, which encodes a type IV secretion system and the CagA toxin. This secretion system allows H. pylori to inject the CagA oncoprotein into host cells, causing multiple cellular perturbations. Despite the high prevalence of H. pylori infection, only a small percentage of affected individuals develop significant clinical outcomes, while most remain asymptomatic. Therefore, understanding how H. pylori triggers carcinogenesis and its immune evasion mechanisms is critical in preventing gastric cancer and miti-gating the burden of this life-threatening disease. This review aims to provide an overview of our current under-standing of H. pylori infection, its association with gastric cancer and other gastric diseases, and how it subverts the host immune system to establish persistent infection.
ARTICLE | doi:10.20944/preprints202304.0339.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Bacillus velezensis; salt stress; sRNA3; Bvs091; galT2
Online: 14 April 2023 (03:28:20 CEST)
During their growth, bacteria respond to complex environmental changes through equally com-plex and orderly regulatory mechanisms. sRNA has an important role as a post-transcriptional regulator in the environmental adaptation of Bacillus. In this study, we identified an sRNA Bvs091 located in the intergenic region of the Bacillus velezensis, which is widely present in the genus Bacillus and whose expression is upregulated by salt treatment. The deletion of bvs091 in B. ve-lezensis PEBA20 led to a reduced growth rate and a change in the phenotypes, with simple colony structures and low and easily degradable biofilm. Salt tolerance tests indicated that the deletion of bvs091 results in a reduced salt tolerance. galT2 mRNA is supposed to be a direct target of Bvs091 according to results obtained by using the bioinformatic method and performing qRT-PCR analysis. The microscale thermophoresis (MST) analysis showed that Bvs091 could directly bind 28‒51 bases in front of the promoter of galT2. Subsequently, the deletion of galT2 in B. velezensis resulted in increased salt tolerance. Based on the techniques of double plasmids and a half-life period, sRNA Bvs091 is confirmed as a trans-encoded sRNA that negatively regulates the mRNA expression of galT2. In brief, the trans-encoded sRNA Bvs091 acts by pairing the incomplete complementary bases of galT2 mRNA, reducing galT2 mRNA’s stability and affecting the trans-lation efficiency.
REVIEW | doi:10.20944/preprints202304.0166.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: glutathione; tuberculosis; mycobacteria; interferons; interleukins; tumor necrosis factor; trans-forming growth factor
Online: 10 April 2023 (10:16:23 CEST)
Glutathione (GSH) is an antioxidant that our cells utilize to prevent damage done by reactive oxygen species, free radicals, peroxides, lipid peroxides, and heavy metals . Due to its immune role in tuberculosis (TB), GSH is hypothesized to play an important part in the immune response against M. tb. Furthermore, one of the hallmark structures of TB is granuloma formation, which involves many types of immune cells. T cells specifically are a major component and are involved in the release of cytokines and activation of macrophages. GSH acts as an important function in macrophages, natural killer cells, and T cells in modulating their activation, their metabolism, the proper cytokine release, the proper redox activity, and free radical levels. For more susceptible patients with HIV and Type 2 Diabetes, the demand for higher GSH levels is increased. This review compiles reports demonstrating the benefits of GSH in improving the immune cell responses against M. tb infection and the use of GSH as adjunctive therapy for TB.
ARTICLE | doi:10.20944/preprints202304.0153.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Burkholderia cepacia complex; bacteriophage; PRD1-like phage; conjugative plasmid
Online: 10 April 2023 (05:46:13 CEST)
The Burkholderia cepacia complex (Bcc) are a group of increasingly multi-drug resistant opportunistic bacteria that can cause severe pulmonary infections. This resistance is driven through a combination of intrinsic factors and the carriage of a broad range of conjugative plasmids harbouring virulence determinants. Therefore, novel treatments are required to not only treat Bcc infection but also to prevent further spread of these virulence determinants. In the search for phages infective for two clinical Bcc isolates, CSP1 phage, a PRD1-like phage was isolated. CSP1 phage was found to require pilus machinery commonly encoded on conjugative plasmids to facilitate infection of multiple Gram-negative bacteria genera including Escherichia and Pseudomonas. Whole genome sequencing and characterisation of one of the clinical Burkholderia isolates revealed it to be Burkholderia contaminans. B. contaminans 5080 was found to contain a genome of over 8 Mbp encoding multiple intrinsic resistance factors, such as efflux pump systems, but more interestingly, carried three novel plasmids encoding multiple putative virulence factors for increased host fitness, including antimicrobial resistance. Even though PRD1-like phages are broad host range, their use in novel antimicrobial treatments shouldn’t be dismissed, as the dissemination potential of conjugative plasmids is extensive. Continued survey of clinical bacterial strains is
ARTICLE | doi:10.20944/preprints202304.0062.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Exosomes; lymphoma; LC-MS; pro-tumoral macrophages; cytokines
Online: 5 April 2023 (12:14:37 CEST)
Macrophages are the key effector cells of innate immunity which show two polarized states: M1, classically activated and M2, alternatively activated. Tumor-associated macrophages (TAMs) which usually show M2 polarization, are immunosuppressive cells that enhance tumor metastasis and invasion. Also, enrichment of TAMs is known to be closely associated with poor prognosis of cancer patients. Therefore, TAMs are considered to be promising targets for immunotherapy. Importantly, tumor-derived exosomes emerged as a crucial player in immune regulation which can remodel the tumor microenvironment towards immunosuppressive state. Of note, few studies have shown that exosomes could induce polarization of macrophages towards M2 type in tumor condition, while others showed activation of M1 or mixed phenotype. Considering the role of TAMs in cancer, there is an urgent need to decipher the exosome-mediated cross-talk between tumor cells and macrophages.For this, we used murine model of Dalton’s lymphoma (DL), wherein, firstly, we evaluated increased exosome burden by assessing exosome level in serum as well as in various tissues of tumor-bearing host. Next, proteomic profiling of lymphoma-derived exosomes was done which revealed the presence of immunomodulatory proteins. Of note, these proteins were known to alter the macrophage polarization. In order to assess the effect of these exosomes on macrophages, we performed in vitro study using RAW264.7 cells. In vitro study revealed that frequent uptake of exosomes mediated a morphological change in macrophages which reduced their phagocytic activity. In parallel, exosomes increased reactive oxygen species (ROS) level and inhibited LPS-induced nitric oxide (NO) level in macrophages. Also, exosomes upregulated the expression of arginase-1 (an M2 marker) in macrophages but decreased the LPS-induced nitric oxide synthase 2 (NOS2) (an M1 marker) expression. Moreover, we observed a pro-tumoral cytokine profile in macrophages incubated with exosomes. Our study suggests that exosome load increases in lymphoma-bearing hosts systemically. Importantly, lymphoma-derived exosomes mediate the activation of macrophages towards pro-tumoral M2 type. Our results give an insight into the exosome-mediated tumor and immune cell cross-talk which could serve as an important prospect for targeting in cancer immunotherapy.
ARTICLE | doi:10.20944/preprints202304.0052.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Bibliometric analysis; Biofilm; Big data; Machine learning; Artificial intelligence
Online: 4 April 2023 (16:07:54 CEST)
Biofilm is a complex community of microorganisms that are attached to surfaces and encased in a self-produced extracellular matrix. Machine learning (ML) techniques have been applied to various aspects of biofilm research, such as predicting biofilm formation, identifying key genes, and designing new therapeutic strategies. In this study, we conducted a bibliometric analysis of machine learning in biofilm research to provide a comprehensive overview of the current state of the field. We searched the Web of Science database for articles published included "machine learning biofilm". A total of 126 articles were identified and analysed. Our results showed that the number of publications on machine learning in biofilm has been increasing rapidly over the past decade, indicating a growing interest in the application of ML techniques to biofilm research. The analysis also revealed that the most common research topics in this area were related to biofilm formation, prediction, and control. Furthermore, the most frequently used ML techniques in biofilm research were artificial neural networks and support vector machines. Overall, our study provides valuable insights into the current trends and future directions of machine learning in biofilm research. It also highlights the importance of interdisciplinary collaboration between biofilm researchers and ML experts to drive innovation in this field.
REVIEW | doi:10.20944/preprints202303.0413.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Coral; Holo-omics; Omics; Meta-omics; microbiota
Online: 23 March 2023 (11:15:45 CET)
This mini-review discusses the importance of microorganisms in various biological processes and the paradigm shift in researchers' perception of microorganisms' biology and genetics. Microorganisms are now understood to interact with their associated microorganisms, and advanced sequencing technology is used to study these interactions. The article highlights the importance of careful study design to efficiently generate and integrate data derived from meta-omics approaches such as (meta)genomics, (meta)transcriptomics, (meta)proteomics, and (meta)metabolomics to fully explore the extent of interactions between host organisms and their associated microbiota. The article also discusses the usefulness of metabarcoding and metagenomics in studying coral holobiont diversity and composition. While metabarcoding can comprehensively explore the genetic diversity of various biological taxa, it has limitations in classifying prokaryotes based on 16S rRNA amplicons. On the other hand, metagenomics generates vast amounts of short reads sequencing data that can be used to examine microbial diversity with greater precision and predict the possible functions of the gene set that is presented in the sample. However, the ability to link species to their functional capabilities is challenging, especially for microbes with uncertain evolutionary relationships, hidden microbes, and microeukaryotes. Finally, the article highlights the potential usefulness of these approaches in conservation biology and molecular and environmental science.
REVIEW | doi:10.20944/preprints202301.0234.v2
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: D-mannose; urinary tract infection; FimH adhesin; product classification
Online: 21 March 2023 (03:42:04 CET)
Background: the nature of alpha-D-mannose - natural aldohexose sugar, C-2 glucose epimer, whose intended use is for preventing urinary tract infections - in the interaction with E. coli is addressed in order to drive the issue of its regulatory classification as a medicinal product or medical device. Methods: PRISMA systematic review approach was applied; Delphi Panel method used to target consensus on statements retrieved from evidence. Results: Based of regulatory definitions and research evidences, the mechanism of D-mannose does not involve a metabolic or immunological action while there is an uncertainty regarding the pharmacological action. Specific interaction between the product and the bacteria within the body occurs, but its nature is inert: it does not induce a direct response activating or inhibiting body processes. Moreover, the action of D-mannose takes place, even if inside the bladder, outside the epithelium on bacteria that have not yet invaded the urothelial tissue. Therefore, its mechanism of action is not directed to host structures but to structures (bacteria) external to the host's tissues. Conclusions: From a regulatory perspective, D-mannose maintains the current medical device classification: new regulations and legal judgments can add further considerations. From a pharmacological perspective, research is driven versus synthetic mannosides: no further considerations are expected on alpha-D-mannose.
REVIEW | doi:10.20944/preprints202303.0301.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: traditional dry fermented sausages; protection policy; desired microbiota; lactic acid bacteria; coagulase negative staphylococci; autochthonous cultures; safety; sensory quality
Online: 16 March 2023 (09:02:51 CET)
Traditional dry fermented meat products are obtained artisanally in many countries, where they represent a gastronomic heritage well distinguished from industrial counterparts. This food category is most often obtained from red meat, a food commodity that is under attack because of evidences of increased risk of cancer and degenerative diseases with high consumption. However, traditional fermented meat products are intended for moderate consumption and gastronomic experience and, as such, their production must be continued also to safeguard culture and economy of the geographical areas of origin. In this review, the main risks attributed to these products are considered and how these risks are minimized by following precise production norms, respectful of the ancient manufacturing processes is described. Moreover, results obtained in studies reporting use of autochthonous microbial cultures of lactic acid bacteria (LAB), coagulase negative staphylococci (CNS), Debaryomyces hansenii and Penicillium nalgiovense to improve safety and quality of traditional fermented meats are summarized. The role of these products as a source of microorganisms that can be beneficial to the host are also considered. From the results of the studies reviewed here it appears that the development of autochthonous cultures for these foods ensure safety and stabilize sensory characteristics with possibility to be extended to the large variety of traditional productions.
ARTICLE | doi:10.20944/preprints202303.0290.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Mucilage microbiome; Shotgun-metagenome sequencing; Comparative marine microbiome
Online: 15 March 2023 (15:24:58 CET)
The intense emergence of mucilage in the Marmara Sea in 2021 has raised concerns due to its potential impact on the global marine system. Considering the potential of mucilage threatening the diverse ecosystems, it is important to define the mucilage microbiome. However, studies dedicated to exploring the biodiversity of mucilage are limited and de novo approaches are needed to understand unexplored biodiversity of mucilage microenvironment. This study aimed to investigate mucilage and water samples from certain stations in Marmara Sea. For this reason, 11 mucilage, 2 pre-mucilage water and 3 clean sea water were collected from 16 stations. DNA isolation, shotgun metagenome sequencing and bioinformatics analysis were performed. It was revealed that the mucilage microbiome and the clean water microbiome were different from each other, and the reads that could not be assigned to any taxon (dark matter) accounted for 58% (p=0.014) of the mucilage metagenome. The clean water had a higher presence of Euryarchaeota (p=0.014), Proteobacteria (p=0.019) and Rhodothermaeota (p=0.034), while Chlamydiae (p=0.014) and Fusobacteria (p=0.034) were found in excess in the mucilage. The study produced the first comparative data on clean sea water and the mucilage microbiome using shotgun metagenomics approaches.
ARTICLE | doi:10.20944/preprints202303.0266.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: drug resistance; flavonoids; RNA-seq; Klebsiella pneumoniae; Rutin; antibacterial agents
Online: 15 March 2023 (02:03:17 CET)
The emergence of drug resistant pathogenic bacteria is increasingly challenging conventional antibiotics. Plant derived flavonoids are considered as potential alternatives to antibiotics due to their antimicrobial properties. However, the mechanisms by which flavonoids modulate pathogenic microorganisms’ growth are not fully understood. In our previous studies we found that Rutin, a kind of flavonoids showed inhibition against Klebsiella pneumoniae strains. In order to better understand its inhibitory mechanism on strain growth, we used both Rutin and Luteolin as treatments to incubate K. pneumoniae ATCC700603 strain. After incubation for 4 hours, the homogenous and differential effects of two different flavonoids on the growth of K. pneumoniae were evaluated. The integrated metabolomic and transcriptomic analysis was performed. The expression levels of 5,483 genes and the contents of 882 metabolites were measured. The differentially expressed genes (DEGs) and metabolites (DEMs) were screened and analyzed. The correlation between DEGs and DEMs were also studied. Our results showed that Rutin could inhibit the strain growth by changing metabolic pathways and ABC transporters pathways. Our study also revealed FU841_RS17580 and FU841_RS19145 as functional genes that played vital roles in the strain growth.
ARTICLE | doi:10.20944/preprints202303.0263.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Exopolysaccharides; Rhizobial; Musa paradisiaca; Musa balbisiana Musa acuminata; EPS-producing Rhizobia
Online: 15 March 2023 (01:35:16 CET)
Exopolysaccharides-EPS are long-chain biopolymer with branched, recurring unit of sugars and non-carbohydrate constituents connected to exterior of cells. Rhizobial, a legume nodulating organism is capable of producing EPS. This study investigated the characteristics’ of some Rhizobium EPS and their effects in shelf life extension of some Musa spp. Rhizobial-EPS was produced using yeast extract mineral medium purified by standard methods. The EPS was characterized to determine functional group, thermal stability, chemical compounds and the monosaccharide component using Fourier Transform Infra-red, Spectroscopy, thermogravimetric Analysis (TGA), Gas Chromatography–Mass Spectrometry and HPLC and their bio-preservative property on post-harvest quality of plantain and different banana was done. The Rhizobial-EPS functional groups were hydroxyl, carboxyl, amine, methyl and ethers associated with polysaccharides. Pentadecanoic acid, octadecanoic acid, oleic acid and heptacosanoic acid, and varied concentration of monosaccharides were detected in the exopolysaccharides. The TGA of the EPS shows a constant loss in weight with two quasi-sharp alterations and almost steady plateau. The EPS coated samples had the lowest weight loss across the samples and as such edible coating was effective in delaying weight loss. The weight loss of Musa paradisiaca (plantain) coated with (EPSA obtained from USDA 110), (EPSB USDA 532C) and (EPSC S2) at the first day were 314 and 314.5g. The initial weight loss of coated and uncoated Musa sp. (Apple Banana), Musa acuminata (Lady Finger), and Musa balbisiana (Cooking Banana), ranged from 72 – 72.7g, 96 – 97g and 95 – 98g respectively. The total sugar of EPS Coated Musa sp. ranges from 0.381 – 0.528mg/L, 0.392 – 0.576 mg/L and 0.41 – 0.598 mg/L at days 1, 2 and 3 respectively. The highest Titratable acidity and pH was observed in EPS coated sample. The results obtained from this study proves that EPS solution is a valuable product for fruit preservation and viable for commercial applications.
ARTICLE | doi:10.20944/preprints202303.0253.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: ASFV; humoral responses; ASFV capsid proteins; ASFV vaccines; ASFV immunity; antigen discovery; luciferase antibody capture assay; luciferase immunoprecipitation assay; viral hemorrhagic fever.
Online: 14 March 2023 (09:43:57 CET)
African swine fever (ASF) is a lethal disease in pigs that has grave socio-economic implications worldwide. For the development of vaccines against African swine fever virus (ASFV), immunogenic antigens that generate protective immune responses need to be identified. There are over 150 viral proteins - many of which are uncharacterized – and humoral immunity to ASFV has not been closely examined. To profile antigen specific antibody responses, we developed luciferase-linked antibody capture assays (LACAs) for a panel of ASFV capsid proteins and screened sera from inbred and outbred animals that were previously immunized with low virulent ASFV before challenge with virulent ASFV. Antibodies to B646L/p72, D117L/p17, M1249L and E120R/p14.5 were detected in this study; however, we were unable to detect B438L specific antibodies. Although OURT88/1 induced viremia was observed in the presence of anti-B646L/p72 antibodies as well as B602L antibodies they were associated with recovery from lethal disease in inbred and outbred animals. However, these antibodies did not correlate with protection against Georgia 2007/1 infection. Antibody responses against M1249L and E120R/p14.5 were observed in animals with reduced clinical signs and viremia. Here we present LACAs as a tool for targeted profiling of antigen specific antibody responses to inform vaccine development.
ARTICLE | doi:10.20944/preprints202303.0098.v2
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antibacterial activity; Psidium guajava; phytochemical screening; liquid-liquid fractionation
Online: 14 March 2023 (04:07:51 CET)
Guava (Psidium guajava L.) is a common fruit tree that grows in several tropical and subtropical parts of the world. The aim of this study was to employ the use of liquid-liquid fractionation to investigative the comparative antibacterial potential of crude extracts of Guava leaves and bark against selected food isolates; Escherichia coli, Pseudomonas aeruginosa, Streptococcus pneumonia, Bacillus cereus and Staphylococcus aureus. The phytochemical analysis of the extract showed presence of tannin, phenol, flavonoid and terpenoid in all extract, while steroid and saponin were absent in some. The agar diffusion method was employed for the assessment of the sensitivity of the extracts. The ethyl acetate and aqueous fractions from the stem bark acetone extract generally showed better antimicrobial activity compared with other extracts from leaves. The extract was active both against gram positive bacteria (Bacillus cereus and Streptococcus pneumonia) and gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, , Bacillus cereus and Staphylococcus aureus) at varying zone of inhibition. The results of the study showed the potential of identifying novel antibacterial agent from P. guajava bark and leaves while optimising the potential application for treatment in traditional medicine.
ARTICLE | doi:10.20944/preprints202303.0218.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Analysis; bacterial; pathogens,bacteriology; human health
Online: 13 March 2023 (06:23:55 CET)
The study was geared toward isolating, characterizing and identifying bacterial pathogen in sachet water in addition to determines the bacterial count of the sachet water sold in Obi Local Government Area. Twelve sachet water samples from different companies were analyzed using standard microbiological methods. The microorganism found are Escherichia Coli, Staphylococcus aures, Salmonella spp, with Staphlococuss aureus showing the highest incidence (50%), observed by Escherichia coli (29.17%) and Salmonella spp with the lowest occurrence (20.8%). The presence of these microbes in drinking water possesses a threat to life. The findings consequently suggest that some of the sachet water sold in obi L.G. A are not healthy for human intake and are risky to health. Hence there's need for strict concern and routine monitoring by regulatory agencies to make sure that appropriate treatment is applied inside the manufacturing of exceptional and safe sachet drinking water. This study is aimed to analyze the bacteriological quality of some selected sachet water in Obi Local Government Area of Benue State, Nigeria.
ARTICLE | doi:10.20944/preprints202303.0204.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Bioremediation; copper nitrate; Penicillium sp.; kefir; inorganic contaminant.
Online: 13 March 2023 (02:18:00 CET)
This work aimed to carry out a bioremediation study to evaluate the resistance of Penicillium sp. isolated from kefir grains for the treatment of copper. The fungal culture medium was prepared using a 2% malt-agar medium at pH 7.0 in which Penicillium sp. was inoculated. Penicillium sp. growing in a liquid medium showed a decrease in biomass in presence of Cu(NO3)2 (800 mg.L-1), suggesting that the metal impacts the growth rate of the fungus. Moreover, the combined factors of pH and the presence of the inorganic contaminant impacted the radial growth of the fungus, causing inhibition of 73% at pH 4.0, 75% at pH 7.0, and 77% at pH 9.0 in liquid medium compared to control. However, images obtained with scanning electron microscopy showed the integrity of the fungus cell, even at high doses of copper in the medium. Therefore, it can be concluded that Penicillium sp. isolated from kefir grain can bioremediate the environment and that the harmful effects of heavy metals can be minimized as a result biosorption. Although the growth of Penicillium sp. is inhibited, such retardation requires high doses of copper nitrate, thus ensuring the use of this microorganism for protection against the harmful effects of non-essential copper in the environment.
ARTICLE | doi:10.20944/preprints202303.0175.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Whole genome sequence; Plesiomonas genus; Plesiomoniasis; Aquaculture
Online: 9 March 2023 (09:56:40 CET)
Plesiomonas shigelloides is the only species in the genus and has zoonotic importance due to its serious implications resulting from the consumption of contaminated seafood. This is the first report on the genomic features of the whole-genome sequence (WGS) of P. shigelloides strain V-78 recovered from diseased rainbow trout, Oncorhynchus mykiss. The genome of P. shigelloides V-78 consists of 4,478,098 base pairs (bp), which encode 3730 proteins and has a G+C content of 51.1%. The bioinformatics analysis of WGS of V-78 confirmed the presence of 121 tRNA genes and 42 rRNA genes (15 genes for 5S rRNA, 13 genes for 16S rRNA and 14 genes for 23S rRNA). Comprehensive genome analyses revealed that the strain encodes for secondary metabolites, antimicrobial resistance, and virulence genes. The strain V-78 has 31 known antibiotic resistance models, which encode many antimicrobial resistances. Also, strain V-78 has 42 different virulence genes such as adhesion, secretion system, and motility. The digital DNA-DNA hybridization value against P. shigelloides NCTC 10360 was 74.2%, while the average nucleotide identity value was 97.1%. Based on the scrutinized analysis of genomic data, strain V-78 should be considered a novel subspecies of P. shigelloides, for which Plesiomonas shigelloides subsp. oncorhynchi is proposed.
ARTICLE | doi:10.20944/preprints202303.0173.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Vibrio; Oysters; Post-harvest; Modelling; Temperature; Ice-treatment
Online: 9 March 2023 (09:40:44 CET)
Temperature is a critical factor that influences the proliferation of pathogens in hosts. The impact of temperature on pathogens is commonly explored in controlled and constant temperatures. Experiments under varying environmental temperature are becoming more frequent, however, testing every temperature scenario à la carte is unachievable. One example of this is the human pathogen Vibrio parahaemolyticus (Vp) in oysters. Here, a predictive model was developed for predicting the growth of Vp in oysters under varying ambient temperature. The model was fitted and evaluated against data from experiments studying growth and inactivation of Vp in oysters at eight constant temperatures. Once evaluated, Vp dynamics in oysters were estimated at different post-harvest varying temperature scenarios affected by water and air temperature, and different ice treatment timing. The model performed adequately under varying temperature, reflecting that (i) increasing temperature, particularly in hot summers, favors a rapid Vp growth in oysters, resulting in a very high risk of gastroenteritis in humans after consumption of a serving of raw oysters, (ii) pathogen inactivation due to day/night oscillations, and more evidently, due to ice treatments, (iii) ice treatment is much more effective limiting risk of illness when applied immediately onboard compared to dockside. The model results to be a promising tool for improving the understanding of the Vp-oyster system and support studies on public health impact of pathogenic Vp associated with raw oyster consumption. Although robust validation of the model predictions is needed, initial results and evaluation show the potential of the model to be easily modified to match similar systems where the temperature is a critical factor shaping the proliferation of pathogens in hosts.
ARTICLE | doi:10.20944/preprints202303.0160.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Exercise; IL-17; IL-10; Interleukin. Exercise-Induced Inflammatory State
Online: 9 March 2023 (02:11:14 CET)
Here we investigated the acute effects of an exhaustive intermittent exercise session on immunological parameters of the elderly and the subsequent incidence of upper respiratory tract infections and compare with the moderate-intensity. To do so, ixty-three old subjects were divided into three groups HIIT (n=21) submitted at one High-intensity interval training, SCG (n=21) kept in a sedentary state, and MICT (n=21) submitted at moderate intensity walking. Blood were collected at 5 time points, before, immediately after, 2h, 24h, and 48h after the intervention. In result the IL-6 and TNF-α were overexpressed immediately after the IL-10 stood overexpressed and correlated with IL-17, denoting an inflammatory process, and evidencing an immunologic competence without enhancement of the prevalence of upper respiratory infection tract (URTIs). So a modulation in the balance of Th1/Th2/Th17 cytokines and leukocytes, these modifications did not cause the effect characterized as an immunological window. Perhaps, the typical inflammation process, with IL-10 and IL-17 participation could also produce benefits to combat infections, a pertinent discussion during a post-pandemic time; we consider it a safe exercise program for older adults.
REVIEW | doi:10.20944/preprints202303.0144.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Humulus lupulus; hop creep; beer; brewing; plant microbial community; glycosyl hydrolase; hop processing
Online: 8 March 2023 (03:38:36 CET)
Background Hop creep continues to present an unresolved issue for the brewing industry, specifically stemming from those hops added to beer during fermentation. Hops have been found to contain four dextrin-degrading enzymes: alpha amylase, beta amylase, limit dextrinase, and an amyloglucosidase. One recent hypothesis predicts that these dextrin-degrading enzymes could originate from microbes rather than the hop plant itself. Scope and Approach This review begins by describing how hops are processed and used in the brewing industry. It will then discuss hop creep’s origins with a new beer style, antimicrobial factors from hops and resistance mechanisms that bacteria use to counter them, and finally microbial communities that inhabit hops, focusing on whether they can produce the starch degrading enzymes which drive hop creep. After initial identification, microbes with possible links to hop creep were then run through several databases to search the genomes (if available) and for those specific enzymes. Key Findings and Conclusions Several bacteria and fungi contain alpha amylase as well as unspecified glycosyl hydrolases, but only one contains beta amylase. Finally, this paper closes with a short summary of how abundant these organisms typically are in other flowers.
REVIEW | doi:10.20944/preprints202303.0140.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: COVID-19; genetic vaccines; adverse reactions; autoimmunity; immunohistochemistry; spike protein
Online: 8 March 2023 (02:57:33 CET)
As a result of the spread of SARS-CoV-2, a global pandemic was declared. Indiscriminate COVID-19 vaccination has been extended to include age groups and naturally immune people with minimal danger of suffering serious complications due to COVID-19. Solid immuno-histopathological evidence demonstrates that the COVID-19 genetic vaccines can display an off-target distribution in tissues that are terminally differentiated, triggering autoimmune reactions. These include the heart and brain, which may incur in situ production of spike protein eliciting a strong autoimmunological inflammatory response. Due to the fact that every human cell which synthesizes non-self antigens becomes inevitably the target of the immune system, and since the human body is not a strictly compartmentalized system, accurate pharmacokinetic and pharmacodynamic studies are needed in order to determine precisely which tissues can be harmed. Therefore, our article aims to draw the attention of the scientific and regulatory communities on the critical need of bio-distribution studies for the genetic vaccines against COVID-19, as well as of rational harm-benefit assessments by age group.
ARTICLE | doi:10.20944/preprints202303.0125.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Amoeba; Meningitis; Meningoencephalitis; free-living amoeba; Peru
Online: 7 March 2023 (03:44:06 CET)
Background: Free-living amoebas (FLA), also amebas, are eukaryotic and mitochondrial microorganisms that are capable of growing in any environment, aquatic or terrestrial. These free-living amoebas are mostly non-pathogenic to humans. However, there exist some highly pathogenic species, such as Acanthamoeba — mainly T-4 genotype —, Naegleria fowleri (known as brain-eating amoeba), and Balamuthia mandrillaris. They can be called "brain-eating amoebas” because of their ability to cause substantial destruction of brain tissue. There is no standard treatment; immunological processes which predispose humans to acquire and infection and, then, a disease are unknown. In addition, there are other species of free-living amoebas such as, Sappinea pedata, Vermamoeba vermiformes, Vanellas sp,Vahlkampfia sp., and, more recently, Paravahlkampfia francinae, which is less virulent and aggressive than the first three mentioned above. Methods: All CSF samples were evaluated in our laboratory under the microscope. Monoxenic and axenic cultures were negative as well as the presence of cysts or exponential growth. PCR was negative using the FLA primers. Results: Under close observation of sterile CSF, we can see mobile forms of non-human cells. None of the observed forms has the morphotype of Acanthamoeba, Naegleria sp. or Balamuthia mandrillaris. Conclusions: Due to these findings, we know these structures can be observed in the CSF and many of them do not form cysts as others do. In addition, these microorganisms are uncultivable in conventional medium culture to FLA and impossible to detect even when using molecular tools such as PCR, using the primers for EUK A/B or 18s RNAr gene as a target.
REVIEW | doi:10.20944/preprints202301.0456.v2
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: episcopic; imaging; microscopy; annotation; quantification
Online: 6 March 2023 (13:52:22 CET)
Episcopic imaging using techniques such as High Resolution Episcopic Microscopy (HREM) and its variants, allows biological samples to be visualized in three dimensions over a large field of view. Quantitative analysis of episcopic image data is undertaken using a range of methods. In this systematic review, we look at trends in quantitative analysis of episcopic images and discuss avenues for further research. Papers published between 2011 and 2022 were analyzed for details about quantitative analysis approaches, methods of image annotation and choice of image processing software. It is shown that quantitative processing is becoming more common in episcopic microscopy and that manual annotation is the predominant method of image analysis. Our meta-analysis highlights where tools and methods require further development in this field, and we discuss what this means for the future of quantitative episcopic imaging, as well as how annotation and quantification may be automated and standardized across the field.
ARTICLE | doi:10.20944/preprints202303.0085.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Chronic hepatitis B infection; Therapeutic vaccines; Regulatory T cells; Functional cure; GMI-HBVac; Mafosfamide
Online: 6 March 2023 (03:37:38 CET)
Chronic hepatitis B infection remains a significant worldwide health burden, placing persons at risk for hepatocellular cancer and hepatic fibrosis. Chronic hepatitis B virus (CHB) infection is characterized by elevated levels of immunosuppressive regulatory T cells (Tregs), which can inhibit the function of effector T cells and lead to an insufficient immune clearance response against HBV in the host. Theoretically, suppression of Treg functionality and percentage could increase anti-HBV reactivity in CHB-infected patients, although this has not yet been explored. We attempted to enhance our previously established anti-CHB protocol utilizing the GM-CSF+IFN-α+rHBVvac regimen (GMI-HBVac) by incorporating Mafosfamide (MAF), which has been utilized in anticancer therapy in the past. Intravenous administration of MAF to rAAV8-1.3HBV-infected mice resulted in a dose-dependent reduction of Tregs in the blood, rebounding to pretreatment levels 10 days later. To determine the efficacy of anti-CHB, 2ug/ml MAF was combined with the GMI-HBVac in an HBV-infected animal model as an anti-Treg treatment. When rAAV8-1.3HBV-infected mice were immunized with MAF+GMI-HBVac, peripheral blood Tregs decreased significantly, leading to dendritic cell activation, HBV-specific T cell proliferation, and upregulation of IFN-gamma producing CD8+T cells. In addition, MAF+GMI-HBVac vaccination stimulates T cell infiltration in HBV-infected liver. These conditions may contribute to an enhanced immune response and the clearance of HBV-associated antigens, including serum HBsAg, serum HBcAg, and HBcAg+ hepatocytes. Overall, this is the first indication that MAF was utilized as an adjuvant to deplete Tregs and paired with GMI-HBVac as a unique therapeutic vaccine regimen against established CHB mice to produce a functional cure, as seen by the remarkable clearance of HBsAg.
REVIEW | doi:10.20944/preprints202303.0080.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Virus-fortification; antimicrobial; active packaging films; bacteriophages
Online: 6 March 2023 (02:20:53 CET)
Research and development on innovative packaging materials have advanced significantly to safeguard packaged food against microbial contamination and oxidation. To combat demanding issues, active packaging has evolved as a viable method for minimizing oxidation/microbial growth in packaged goods, extending their shelf life, and ensuring the consumer's safety. Active food packaging includes O2, CO2 scavengers, moisture absorbers, U.V. barriers, and carriers of antioxidant and antimicrobial agents. Various antimicrobial agents are carried and/or incorporated into food packaging formulations. Consumers demand natural antimicrobials over chemical/synthetic ones, such as bacteriocins, bacteriophages, and essential oils. Bacteriophages (viruses) have emerged as a feasible option for decontaminating and eliminating infections from food sources. These viruses can target specific food-borne pathogens without impairing beneficial bacteria and, most critically, without causing disease in humans or animals. Fortifying bacteriophages into food packaging films will not only kill specific food microorganisms but has evolved as a new weapon to combat antimicrobial-resistant (AMR) issues. The present review summarises recent developments in active antimicrobial packaging focused particularly on bacteriophage-food packaging applications and advantages, drawbacks, and future trends for active food packaging.
ARTICLE | doi:10.20944/preprints202303.0048.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Minimum Inhibitory Concentrations; Deep Learning; Regression; Antimicrobial peptides; Drug Discovery
Online: 3 March 2023 (01:29:51 CET)
Antimicrobial peptides (AMPs) are a promising alternative to antibiotics to combat drug resistance in pathogenic bacteria. However, the development of AMPs with high potency and specificity remains a challenge, and new tools to evaluate antimicrobial activity are needed to accelerate the discovery process. As a step toward direct prediction of the experimental minimum inhibitory concentration (MIC) of AMPs, we proposed MBC-Attention, a combination of a multi-branch CNN architecture and attention mechanism. Using a curated dataset of 3929 AMP against Escherichia coli, the optimal MBC-Attention model achieved an average Pearson correlation coefficient of 0.775 and an RMSE of 0.533 (log μM) in three independent tests of 393 sequences each. This results in a 5–12% improvement in PCC and 7–13% improvement in RMSE compared with RF and SVM models. Ablation studies confirmed that both attention mechanisms contributed to performance improvement.
ARTICLE | doi:10.20944/preprints202303.0040.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Gut microbiota; Dysbiosis; Demography; Firmicutes; Proteobacteria; Actinobacteria
Online: 2 March 2023 (10:06:05 CET)
The gut microbiome offers numerous advantages to the hosts, through a variety of physiological mechanisms like firming up gut integrity or shaping the intestinal epithelium. Studies showed 2172 species are identified and isolated from human beings, ordered into twelve different phyla, of which 93.5% belonged to Bacteroidetes, Firmicutes, Proteobacteria and Actinobacteria. Out of the 12, three phyla are identified. Human microbial communities are affected by the host external factors like dietary patterns, lifestyle factors, antibiotic usage, internal factors gender, host genotype, age and race. To analyze the dysbiosis and bacterial variation in different areas of District Faisalabad 10,000 individuals of age 25–35 years were recruited from the two different rural and urban localities. The oral swab and fecal sample were collected according to prescribed manner. The collected samples from demographically and geographically distinct regions of District Faisalabad were subjected to DNA extraction and quantification. The amplification of 16s rRNA was carried out by PCR and visualized through a transilluminator. The results revealed significant elevated, % abundance of fecal microbial profile Blautia spp, Firmicutes, Ruminococcaceae, in rural population however non-significant difference % abundance of total Bifido, E. coli, Faecali bacteria, total Lactobacillus were identified in both demographically distinct regions. The pathogenic Gamma Protebacteria, Fusobacterium, Campylobacter coli were not detected in both study areas. Out of five orally detected microbial profiles, elevated % abundance of Firmicutes was detected in rural population however non-significant difference was observed in % abundance of total Bifido and E. coli in both populations. Total Lactobacillus and Fusobacterium were not detected in oral sample of both urban and rural population. Conclusively, this research accomplished the potential effects of demographic and geographical induced dysbiosis in the normal microbiome of the oral cavity and intestine that might cause dysbiosis associated disorders.
REVIEW | doi:10.20944/preprints202303.0030.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Coccidioides; coccidioidomycosis dissemination; skeletal infection; fungal osteomyelitis; fungal synovitis; arthritis; knee joint
Online: 2 March 2023 (04:12:01 CET)
Valley fever or coccidioidomycosis is a pulmonary infection caused by several species of coccidi-oides (Cocci) fungi that is endemic to California and Arizona. Skeletal coccidioidomycosis ac-counts for about half of disseminated infections, with the vertebral spine being the preferred site of dissemination. Most cases of skeletal coccidioidomycosis progress to bone destruction or spread to adjacent structures such as joints, tendons, and other soft tissues causing significant pain and restricting mobility. Manifestations of such cases are usually non-specific, making di-agnosis very challenging, especially in non-endemic areas. In this review, we explore case reports of dissemination of coccidioidomycosis to bones and/or joints to highlight key differential fea-tures with other conditions or diseases and highlight opportunities for mechanistic and pre-clinical studies that can help improve diagnostics, prognostics, and treatments.
ARTICLE | doi:10.20944/preprints202302.0492.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: digestibility; essential oils; hydrolyzable tannins; rumen fermentation; ruminal bacteria.
Online: 28 February 2023 (02:41:58 CET)
The objective of this study was to evaluate the effect of the addition of a phytogenic compounds blend (PHA) containing hydrolyzable tannins, carvacrol and cinnamaldehyde oil in the mineral salt or energy supplement on the rumen microbiota and nitrogen metabolism of grazing Nellore cattle. Eight castrated Nellore steers were distributed in a double Latin square 4 × 4 design, with a 2 × 2 factorial arrangement (two type supplements and the addition or not of PHA) as follows: energy supplement without PHA addition (EW); energy supplement with PHA addition (EPHA); mineral supplement without the addition of PHA (MW); and mineral supplement with PHA addition (MPHA). Steers that received supplements with PHA have a lower ruminal proportion of Valerate (with PHA 1.06%; without PHA 1.15%), a lower ruminal abundance of Verrucomicrobia and a tendency for lower DM digestibility (with PHA 62.8%; without PHA 64.8%). Energy supplements allowed higher ammonia concentrations (+2.28 mg of NH3-N/dL), increased the propionate proportion (+0.29% of total VFA), and showed a tendency to have a higher abundance of Bacteroidetes and a lower abundance of Firmicutes in the rumen. The PHA addition in the supplement did not improve the use of nitrogen in grazing cattle, but negatively affected the diet digestibility.
REVIEW | doi:10.20944/preprints202302.0462.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: CD4+ T cells; TCR repertoire; Th17; Treg; paracellular and transcellular
Online: 27 February 2023 (08:45:19 CET)
Controlling CD4+ immune cells infiltration of the brain is a leading aim in designing therapeutic strategies for a range of neuropathological disorders such as; multiple sclerosis, Alzheimer and depression. CD4+ T cells are a highly heterogeneous and reprogrammable family, that includes various distinctive cell types such as Th17, Th1, and Tregs. Interestingly Th17 and Tregs share a related transcriptomic profile, where the TGFβ-SMADS pathway plays a fundamental role in regulating the differentiation of both of these cell types. However, Th17 could be highly pathogenic and was shown to promote inflammation in various neuropathological disorders. Conversely, Treg is anti-inflammatory and is known to inhibit Th17. It could be noticed that Th17 frequencies of infiltration of the blood-brain barrier (BBB) in various neurological disorders are significantly upregulated. However, Treg infiltration numbers are significantly low. The reasons behind these contradicting observations are still unknown. In this perspective, we propose that the difference in the TCR repertoire diversity, diapedesis pathways, chemokine expression and mechanical properties of these two cell types could be contributing to answering this intriguing question.
REVIEW | doi:10.20944/preprints202302.0444.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: SARS-CoV-2; COVID-19; bacteriome; immune system
Online: 27 February 2023 (06:15:38 CET)
The Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) first emerged in 2019 in China and has resulted in millions of human morbidities and mortalities across the globe. It has been shown that this novel virus originated in animals, mutated, and made the cross-species jump to humans. At the time of this communication, the Coronavirus disease (COVID-19) may be on way to an endemic form, however the threat of the virus is more for susceptible (older people and immunocompromised) people. The human body has more bacterial cells than its own, thus making us more bacterial than humans. As a consequence, the bacteriomes in the human body heavily influence human health and disease. The bacteriomes in the body and the immune system seem to be in constant association during bacterial and viral infections. In this review, we identify various bacterial spp. in major bacteriomes (oral, nasal, lung, and gut) of the body in healthy humans and compare them with dysbiotic bacteriomes of COVID-19 patients. We try to identify key bacterial spp. that have a positive effect on the functionality of the immune system and human health. These select bacterial spp. could be used as potential probiotics to counter or prevent COVID-19 infections. In addition, we try to identify key metabolites produced by probiotic bacterial spp. that could have potential anti-viral effects against SARS-CoV-2. These metabolites could be subject to future therapeutic trials to determine their anti-viral efficacy.
ARTICLE | doi:10.20944/preprints202302.0423.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: B-cell; autoimmune disease; drug repurposing
Online: 24 February 2023 (09:11:37 CET)
Autoimmune disorders and some types of blood cancer originate when B lymphocytes malfunction. In particular, when B cells produce antibodies recognizing the body’s proteins, it leads to various autoimmune disorders. And when B cells of various developmental stages transform into cancer cells, it results in blood cancers, including multiple myeloma, lymphoma, and leukemia. Thus, new methods of targeting B cells are required for various patient groups. Here, we used protein kinase inhibitors alectinib, brigatinib, ceritinib, crizotinib, entrectinib, and lorlatinib previously approved as drugs treating anaplastic lymphoma kinase (ALK)-positive lung cancer cells. We hypothesized that the same inhibitors will efficiently target leukocyte tyrosine kinase (LTK)-positive, actively protein-secreting mature B lymphocytes, including plasma cells. We isolated CD19-positive human B cells from the blood of healthy donors and used two alternative methods to stimulate cell maturation toward plasma cells. Using cell proliferation and flow cytometry assays, we found that ceritinib and entrectinib eliminate plasma cells from B cell populations. Alectinib, brigatinib, and crizotinib also inhibited B cell proliferation, while lorlatinib had no or limited effect on B cells. More generally, we concluded that several drugs previously developed to treat ALK-positive malignant cells can be also used to treat LTK-positive B cells.
REVIEW | doi:10.20944/preprints202302.0416.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: AB toxin; diphtheria; botulinum; tetanus; anthrax; cholera; pertussis; shiga toxin; vaccines
Online: 24 February 2023 (03:17:55 CET)
AB toxins have historically been associated with significant morbidity, mortality through infections such as botulinum, anthrax, cholera, and diphtheria. These AB toxin-mediated diseases remain prevalent in low and middle income countries, with intermittent outbreaks of Shiga toxin-producing Escherichia coli (STEC) or whooping cough by Bordetella pertussis in high-income countries. These reports warrant an investigation to better understand the distinct characteristics of AB toxins derived from different pathogens. As toxigenic pathogens broaden their scope and diversity, it amplifies the complexity of the problems posed by their AB toxins. Here, we discuss the history, structure and characteristics of key AB toxins, and report on historical and ongoing research on these toxins. We also explore research avenues that hold great promise in potentially improving clinical management of toxin-mediated diseases in the future.
REVIEW | doi:10.20944/preprints202302.0391.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: small ORF encoded polypeptides (SEPs); riboproteogenomics; bacterial pathogens; protein tagging; proteomics
Online: 23 February 2023 (01:25:52 CET)
The ever-growing repertoire of genomic techniques continues to expand our understanding of true diversity and richness of prokaryotic genomes. Riboproteogenomics laid the foundation for dynamic studies of previously overlooked genomic elements. Most strikingly, bacterial genomes were revealed to harbour robust repertoires of small open reading frames (sORFs) encoding a diverse and broadly expressed range of small proteins, or sORF-encoded polypeptides (SEPs). In recent years, continuous efforts led to great improvements in annotation and characterization of such proteins, yet many challenges remain to fully understand the pervasive nature of small proteins and their impact on bacterial biology. In this work we review recent developments in the dynamic field of bacterial genome reannotation, catalogue important biological roles carried out by small proteins and identify challenges obstructing the way to full understanding of these elusive proteins.
ARTICLE | doi:10.20944/preprints202302.0332.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Tetanus neurotoxin; B-cell linear epitopes; immunological diagnostic; peptide ELISA
Online: 20 February 2023 (08:55:20 CET)
Background: Tetanus is an acute, fatal disease caused by exotoxins released from Clostridium tetani during infections. A protective humoral immune response can be induced by vaccinations with pediatric and booster combinatorial vaccines that contain inactivated tetanus neurotoxin (TeNT) as a major antigen. Although some epitopes in NeNT have been described using various ap-proaches, a comprehensive list of its antigenic determinants that are involved with immunity have not been elucidated. To that end, a high resolution analysis of the linear B-cell epitopes in NeNT was performed using antibodies generated in vaccinated children. Methods: Two hundred sixty-four peptides that cover the entire coding sequence of TeNT protein were prepared in situ on a cellulose membrane by SPOT synthesis and probed with sera from children vaccinated (ChVS) with a triple DTP-vaccine to map continuous B-cell epitopes that were further characterized and validated by immunoassays. Results: Forty-three IgG epitopes were identified. Four (TT-215-218) were chemically synthesized as Multiple Antigen Peptides (MAPs) and used in peptide ELISAs to screen post-pandemic DTP vaccinations. The assay displayed a high performance with high sensitivity (99.99%) and specificity (100%). Conclusions: The complete map of linear IgG epitopes induced by vaccination with inactivated TeNT highlights three key epitopes involved in the ef-ficacy of the vaccine. Antibodies against epitope TT-8/G can block enzymatic activity, and those against epitopes TT-40/G and TT-42/G can interfere with TeNT binding to neuronal cell receptors. We further show that four of the epitopes identified can be employed in peptide ELISAs to assess vaccine coverage. Overall, the data suggest a set of select epitopes to engineer new, directed vaccines
ARTICLE | doi:10.20944/preprints202302.0304.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Urban garden; protease; lipase; DNAse; lipase; Spatial statistics.
Online: 17 February 2023 (07:44:32 CET)
The enzymatic activities of bacterial isolates have been widely studied, but a spatial distribution of this activity is rarely focused. New antibiotic-producing microorganisms can be discovered in a more efficient manner if spatial statistical techniques are applied to the distribution of the activity of bacterial isolates in different terrains. This study is focused to generate a series of maps illustrating the spatial distribution of different soil parameters and the inhibition against relative-safe pathogens (like Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Salmonella, Pseudomonas fluorencens and Enterobacter cloacae) in an urban park in València (Spain). This spatial data has demonstrated a higher proportion of isolates was specifically allocated. This routine of data presentation is valuable for understanding bacterial population dynamics at a local level.
ARTICLE | doi:10.20944/preprints202302.0246.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Cigar; stacking fermentation; microbial community; volatiles; interaction; aroma
Online: 15 February 2023 (01:49:13 CET)
Cigar stacking fermentation is a key step in tobacco aroma enhancement and miscellaneous gas reduction, which both have a great influence on increasing cigar flavor and improving industrial availability. To analyze the effect of cigar tobacco leaf (CTLs) microbial community structure on volatiles during cigar stacking fermentation, this study used multi-omics technology to reveal the changes in microbial community structure and volatiles of different cigar varieties during stacking fermentation, in addition to exploring the interaction mechanism of microbiome and volatiles. The results showed that the dominant microbial compositions of different CTL varieties during stacking fermentation were similar, which included Staphylococcus, Corynebacterium 1, Aerococcus, and Aspergillus. These dominant microbes mainly affected the microbial community structure and characteristic microorganisms of CTLs through microbial interactions, thereby influencing the transformation of volatiles. Characteristic microorganisms of different CTLs varieties such as Trichothecium, Trichosporon, Thioalkalicoccus and Jeotgalicoccus, were found to posively correlate with characteristic volatiles like megastigmatrienone 4, pyrazine, tetramethyl-, geranyl acetone, and 2-undecanone, 6,10-dimethyl-, respectively. This in turn affected the aroma and sensory quality of the CTLs. This study provides theoretical support for the analysis of the mechanism of microorganisms on volatiles and aroma, and development of microbial agents during cigar stacking fermentation.
REVIEW | doi:10.20944/preprints202302.0234.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: lipid metabolism; Apicomplexa; drug discovery; calcium signaling; acidocalcisomes; parasite
Online: 14 February 2023 (04:42:12 CET)
Calcium signaling and lipid metabolism are crucial in the infection processes of Apicomplexans parasites. Thus, enzymes involved in these processes can be drug targets against Apicomplexans. For example, in malaria infection, in-depth research into lipid metabolic pathways is crucial in understanding the parasite's infection cycle, particularly during its erythrocytic infection cycle, which has been demonstrated to be a critical stage during the disease progression. Most enzymes that play critical roles in lipid synthesis and calcium signaling have been extensively studied; nonetheless, a vast knowledge gap still exists, especially on specific enzymes and their roles in the transmission and progression of the Apicomplexan parasites. Many types of infections caused by Apicomplexans are life-threatening and hard to treat. These intracellular parasites proliferate within parasitophorous vacuoles in their host cells. As the parasites multiply, they need to meet their high demand for nutrients such as amino acids and lipids. They can acquire nutrients through scavenging and biosynthesis. This review summarizes a few interesting, unique pathways in selected Apicomplexa and how such unique pathways can be targets for drugs.
ARTICLE | doi:10.20944/preprints202302.0227.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Parkinson’s Disease; MPP+; Neuroinflammation; Oxidative Stress Proinflammatory cytokines
Online: 14 February 2023 (03:18:57 CET)
Parkinson’s disease is a neurodegenerative disorder characterized by oxidative stress and immune activation in the nigro-striatal pathway. Simvastatin regulates cholesterol metabolism and protects from atherosclerosis disease. Simvastatin or tween-80 was administered 7 days before sterotaxic intrastriatal administration of MPP+ (1-methyl-4-phenylpyridine) in rats. Fluorescent lipidic product formation, dopamine levels, and circling behavior were considered damage markers. Twenty-four h and six days after, the animal group lesioned with MPP+ showed significant damage in relation to the control group. Animals pretreated with simvastatin reduced significantly the MPP+-induced damage compared to MPP+ treated group. As apoptosis promotes neuroinflammation and neuronal degeneration in Parkinson’s disease, and since there is not currently a proteomic map of the Nigro striatum of rats, and assuming a high homology among the identified proteins in other rat tissues, we based the search for rat protein homologs related to the establishment of inflammation response. We demonstrate that most proteins related to inflammation are decreased in the simvastatin-treated rats. Furthermore, differential expression of antioxidant enzymes in striated tissue of rat brains was found in response to simvastatin. These results suggest that simvastatin could prevent striatal MPP+-induced damage and for the first time the molecular mechanisms involved in this protective effect.
REVIEW | doi:10.20944/preprints202302.0074.v3
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Lumpy skin disease virus; lumpy skin disease; epidemiological footprint and multi-country outbreak; transboundary spread and disease resurgence; diagnosis and vaccines
Online: 13 February 2023 (14:44:26 CET)
The lumpy skin disease virus (LSDV) is an animal virus and a member of the Poxviridae family, which causes lumpy skin disease (LSD) in livestock animals like cows and buffaloes. LSD is an important transboundary disease of economic importance that was first discovered in 1929 in Zambia. LSDV has been prevalent in African countries, where several outbreaks have been reported previously. However, the virus has spread rapidly across the Middle East in the past two decades, reaching Russia and, recently, the Asian subcontinent. With the unprecedented cluster outbreaks reported across Asian countries, LSDV is certainly undergoing an epidemiological shift and expanding its geographical footprint globally. The recent LSD outbreaks have gained attention from global regulatory authorities and raised serious concerns among epidemiologists and veterinary researchers. Although there is no dearth of knowledge about LSDV, the disease lacks networked global surveillance and management, consequently making the current statistics deficient, fragmented, and unreliable. Hence, recurrent LSD outbreaks seriously threaten the global livestock industry. This review provides recent insights into LSDV by augmenting latest literature associated with its epidemiology, pathogenesis, transmission, currently-available intervention strategies, and economic implications on the dairy industries. The review also critically examines the changing epidemiological footprint of LSD and speculates on the possible reasons contributing to the ongoing multi-country LSD outbreak.
ARTICLE | doi:10.20944/preprints202302.0185.v3
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: methanogenesis; pig manure; carbon sources; C. cellulovorans; methanogens
Online: 13 February 2023 (02:08:26 CET)
Methane (CH4) has attracted attention as not only synthetic natural gas, but also one of the hy-drogen carriers in terms of energy density. On the other hand, there exist bacterial ecosystems in nature that can decompose organic compounds to produce CH4 and CO2. In this study, Clostridi-um cellulovorans was first cultivated with pig manure (PM) as an unused biomass. Regarding the measurement of organic acids by high-performance liquid chromatography (HPLC), acetate and butyrate were increased in the C. cellulovorans medium containing 0.5% PM, while formate and lactate were decreased in it. Next, in comparison with carbon sources such as glucose, cellobiose, and acetate, cocultivation of C. cellulovorans and Methanosarcina mazei or microbial flora of me-thane production (MFMP) was performed in the C. cellulovorans medium. These results revealed that 0.5% acetate as the sole carbon source produced CH4 only by cocultivating C. cellulovorans and MFMP. Furthermore, MFMP was only cultivated with 1% acetate or 1% methane as a carbon source after precultivated with 0.5% glucose medium for 12 h. As a result, methane productivity of MFMP with 1% methanol medium was approximately eight times higher than that with 1% acetate medium. Finally, next-generation sequencing (NGS) analysis of MFMP after cultivation with 1% acetate or 1% methane was carried out. Interestingly, Methanofollis (0.211%) belonging to H2/CO2 -using methanogens (CO2 reduction pathway) was dominant in the 1% acetate medium for 72 h cultivation, whereas Methanosarcina siciliae (1.178%), M. barkeri (0.571%), and Methano-follis (0.490%) were major species in 1% methanol medium for 72 h cultivation. Since Methano-sarcina spp. are belonging to acetoclasts (acetoclastic pathway), methanol could promote to grow Methanosarcina spp. rather than acetate. Therefore, it seemed Methanosarcina spp. may play a key methanogenesis in MFMP. Thus, these results will provide important information for low cost biomethane production.
ARTICLE | doi:10.20944/preprints202302.0113.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Entomopathogenic fungi; Growth promoters; Nutrient Solubilization; Bioavailability; Iron acquisi-tion genes; ferric reductase activity
Online: 7 February 2023 (02:54:53 CET)
Endophytic insect pathogenic fungi have a multifunctional lifestyle; in addition to its well-known function as biocontrol agents, it may also help plants respond to other biotic and abiotic stresses, such as iron (Fe) deficiency. This study explores M. brunneum EAMa 01/58-Su strain attributes for Fe acquisition. Firstly, direct attributes include siderophore exudation (in vitro assay) and Fe content in shoots and in the substrate (in vivo assay) were evaluated for three strains of Beauveria bassiana and Metarhizium bruneum. The M. brunneum EAMa 01/58-Su strain showed a great ability to exudate iron siderophores (58.4% surface siderophores exudation) and provided higher Fe content in both dry matter and substrate compared to the control and was therefore selected for further research to unravel the possible induction of Fe deficiency responses, Ferric Reductase Activity (FRA), and relative expression of Fe acquisition genes by qRT-PCR in melon and cucumber plants.. In addi-tion, root priming by M. brunneum EAMa 01/58-Su strain elicited Fe deficiency responses at transcriptional level. Our results show an early up-regulation (24, 48 or 72 h post inoculation) of the Fe acquisition genes FRO1, FRO2, IRT1, HA1, and FIT as well as the FRA. These results highlight the mechanisms involved in the Fe acquisition as mediated by IPF M. brunneum EAMa 01/58-Su strain.
ARTICLE | doi:10.20944/preprints202302.0099.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: manganese; cGAS-STING pathway; RNA virus; antiviral function; redundant mechanisms
Online: 6 February 2023 (10:01:21 CET)
The innate immune system is the first line of host defense sensing viral infection. Manganese (Mn) has recently been found to be involved in the activation of innate immune DNA sensing cGAS-STING pathway and subsequent anti-DNA virus function. However, whether Mn2+ mediates host defense against RNA viruses is still unclear. In the current study, we demonstrated that Mn2+ exhibited antiviral effects against various animal and human viruses including RNA viruses such as PRRSVs and the VSV as well as a DNA virus such as the HSV1 in a dose-dependent manner. Moreover, cGAS and STING were both investigated in the Mn2+ mediated antiviral roles using the knockout cells made by CRISPR-Cas9 approach. Unexpectedly, the results revealed that neither cGAS knockout nor STING knockout had any effect on Mn2+ mediated antiviral functions. Nevertheless, we verified that Mn2+ promoted the activation of cGAS-STING signaling pathway. These findings suggest that Mn2+ has broad spectrum antiviral activities in a cGAS-STING pathway independent manner. This study also provides significant insights into redundant mechanisms participating in the Mn2+ antiviral functions and also indicates new target for Mn2+ antiviral therapeutics.
ARTICLE | doi:10.20944/preprints202302.0094.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Vibrionaceae; Pseudoalteromonas; multipartite; bipartite; pangenome; horizontal gene transfer; codon usage bias; chromid
Online: 6 February 2023 (09:43:23 CET)
Multipartite bacteria have one chromosome and one or more chromid. Chromids are believed to have properties that enhance genomic flexibility, making them a favored integration site for new genes. However, the mechanism by which chromosomes and chromids jointly contribute to this flexibility is not clear. To shed light on this, we analyzed the openness of chromosomes and chromids of the two bacteria, Vibrio and Pseudoalteromonas, both in the Enterobacterales order of gamma-proteobacteria, and compared it with monopartite genomes in the same order. We applied pangenome analysis, codon usage analysis and the HGTector software to detect horizontally transferred genes. Our findings suggest that the chromids of Vibrio and Pseudoalteromonas likely originated from two separate plasmid acquisition events. Bipartite genomes were found to be more open compared to monopartite. We found that the shell and cloud pangene categories drive the openness of bipartite genomes in Vibrio and Pseudoalteromonas. Based on this and our two recent studies, we propose a hypothesis that explains how chromids and the chromosome terminus region contribute to the genomic plasticity of bipartite genomes.
REVIEW | doi:10.20944/preprints202302.0067.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: fecal microbiota transplantation; horse; gut microbiota
Online: 3 February 2023 (09:50:36 CET)
Equine fecal microbiota transplantation (FMT) is an emerging therapy for restoring gut microbiome balance in horses. An imbalance in the gut microorganisms, known as dysbiosis, can cause inflammation and metabolic disruptions. FMT, which involves transferring gut bacteria from a healthy donor to a diseased recipient, has shown positive results in treating gastrointestinal diseases in horses, but is still largely limited to research purposes due to safety concerns and lack of understanding of its mechanisms. This paper aims to shed light on the possible mechanisms of FMT in horses and discuss future perspectives for its clinical application. Further research is needed to develop more effective and safer FMT techniques for horses.
REVIEW | doi:10.20944/preprints202302.0054.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Chagas Disease; surface proteins; disperse protein family; Trypanosoma cruzi
Online: 3 February 2023 (03:11:08 CET)
Abstract Chaga´s disease caused by Trypanosoma cruzi infections is included in the group of neglected diseases, and efforts to develop new therapeutic or immunoprevention approaches have not been successful. After the publication of the T. cruzi genome, the number of molecular and biochemical studies on this parasite have increased considerably, many of which are focused on families of variant-surface-proteins, especially the trans-sialidases, mucins and mucin-associated proteins. The disperse gene protein 1 family (DGF-1) is one of the most abundant families in the T. cruzi genome, however, the large gene size, high copy numbers, and low antibody titers detected in infected humans make it an unattractive study target. Here, we argue that the DGF-1 gene family although not being the most obvious participant of the host-parasite immunological gamble, where T. cruzi appears to have the upper hand, it may play an important role in more basic host-parasite interactions that deserve further examination.
ARTICLE | doi:10.20944/preprints202302.0014.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: neonatal sepsis; blood culture; early-onset sepsis; late-onset sepsis; FilmArray® blood culture identification panel; neonates.
Online: 1 February 2023 (11:50:19 CET)
This prospective single-center study was designed to assess the clinical utility of the FilmArray® blood culture identification (BCID) panel for improving the diagnostic accuracy in neonatal sepsis. Results obtained using the FilmArray® BCID panel were correlated with results of blood culture in all consecutive neonates with suspicion of early-onset (EOS) and late-onset sepsis (LOS) attended in our service over a 2-year period. A total of 102 blood cultures from 92 neonates were included, 69 (67.5%) in cases of EOS and 33 (32.3%) in LOS. The FilmArray® BCID panel was performed in negative culture bottles at a median of 10 hours of blood culture incubation (range 7.5-20 hours), without differences by the type of sepsis. The FilmArray® BCID panel showed a 66.7% sensitivity, 100% specificity, 100% positive predictive value, and 95.7% negative predictive value. There were four false-negative cases, three of which of Streptococcus epidermidis in neonates with LOS and one case of Granulicatella adiacens in one neonate with EOS. We conclude that the use of the FilmArray® BCID panel in negative blood cultures from neonates with clinical suspicion of sepsis is useful in decision-making of starting or early withdrawal of empirical antimicrobials because of the high specificity and negative predictive values of this assay.
ARTICLE | doi:10.20944/preprints202301.0540.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: β -Lapachone; Bactericidal; Biofilms; Resistant; Zone of inhibition; Antimicrobial activity
Online: 30 January 2023 (06:10:49 CET)
Background: Bacterial infections constantly have a large impact on public health, because of increased rates of resistance and reduced frequency of development of novel antibiotics. The utility of conventional antibiotics for treating bacterial infections has become increasingly challenging. The aim of the study was to assess the antibacterial effect of β -Lapachone, a novel synthetic compound. Methods: The antibacterial activity of the β -Lapachone compound was examined against laboratory strains by agar well diffusion method, minimal inhibitory concentration (MICs), and minimal bactericidal concentration (MBCs). Growth kinetics inhibition in presence of β -Lapachone on Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa (ATCC 27853) was assessed by MABA. Crystal violet blue assay was used for biofilm inhibition assays, biofilm eradication assay and for molecular modeling PyMOL was used. Results: β -Lapachone exhibited potent antimicrobial activity against laboratory strains of bacteria with MIC of 0.2 mM for S. saprophyticus and Staphylococcus aureus, and 0.04 mM for Staphylococcus epidermidis and Pseudomonas aeruginosa ATCC 27853. The inhibition of catalase enzyme was found to be the cause for its antibacterial activity. Molecular modeling predicted the binding of β -Lap at active site and heme binding site of catalase, KatA. The activity of some commercial antibiotics was enhanced in association with β -Lap. In addition, β -Lap inhibited the biofilm formation and eradicated the already formed and ultra-mature biofilms of aforesaid bacterial strains.
ARTICLE | doi:10.20944/preprints202301.0497.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: matrix metalloproteinases; skin fibrosis; gene expression; laser therapy
Online: 27 January 2023 (07:17:38 CET)
Matrix metalloproteinases (MMPs) are often considered biomarkers of skin fibrosis. At the early stages of the pathological process, an elevation of their enzymatic activity causes significant changes in the composition of the extracellular matrix. MMPs secreted by immune cells facilitate their migration to the site of damage. Then, the immune cells eliminate the affected cells and biomolecules. Moreover, bidirectional changes in the activity of proteolytic enzymes, including MMPs, accompany wound healing. This study aimed to assess changes in the expression of Mmp2, Mmp3, and Mmp9 after treating the mice with laser therapy using the experimental model of bleomycin-induced skin fibrosis. Using immunohistochemistry, we characterized the histological features of scarred skin. We also analyzed changes in the expression of MMPs using real-time polymerase chain reaction before and after the irradiation with laser. We showed that treatment of the mice with CO2 laser partially normalized the histological features of scarred skin. We also noticed a decrease in the expression of Mmp2, Mmp3 (both p < 0.05), and Mmp9 (p = 0.065) during scar healing. The obtained results suggest that normalization of skin homeostasis requires a control of MMPs activities via induction of their genes.
ARTICLE | doi:10.20944/preprints202301.0489.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: multidrug resistance MDR; EPB (Xenorhabdus, (X. budapestensis, X. szentirmaii, X. innexii) and Photorhabdus) species); CFCM (cell-free conditioned media); NR-AMP (non-ribosomal-templated antimicrobial peptides); anti-microbial, (anti-bacterial, - anti-coccidial, -anti-protist, - activity; cytotoxicity; in vitro; in situ (local) bioavailablity; XENOFOOD; allometry
Online: 27 January 2023 (06:21:56 CET)
Whether the different NR-AMPs could ever be utilized as drugs not only against prokaryotic (bacteria) pathogens but eukaryotic (fungal pathogens, and parasitic protists) depends on the side effects. To get experimental experience about the option of applying EPB-produced antimicrobials to pathogens, and parasites of veterinary significance, we present here the results of an in vitro, and an accompanying in vivo study on chicken. In the in vitro study, we tested the cytotoxic potential of the cell-free conditioned culture media (CFCM) of three entomopathogenic bacterium species, - X. budapestensis, DSM16342 (EMA); X. szentirmaii DSM16338 (EMC); Photorhabdus luminescens ssp. akhurstii TT01 - on chicken tissue culture cells, namely, on the Leghorn Male Hepatoma (LMH),  cells, (a permanent confluent hepato-carcinoma cell line). Each CFCM proved rather cytotoxic in this test. In the in vivo study, we fed freshly hatched male broiler chickens for 42 days with XENOFOOD  which contained autoclaved cultures of EMA, and EMC). These bacteria were grown on standard chicken (starter and grower) [HM3] [u4] feed, and the whole culture was used as a “food supplement”. [HM5]. It had been known that these EPB species cannot grow that is, not viable) atbody temperature (above 33 C).