REVIEW | doi:10.20944/preprints202311.1728.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: Enzymes; Biomass; Waste Management; Waste Treatment; Microorganisms; Applications of Enzymes
Online: 28 November 2023 (09:23:07 CET)
Enzymes are biological molecules produced by living entities for carrying out biological processes. The application of enzymes for waste treatment has been gaining pace commercially to solve concerns related to agricultural residues, wastewater, replacement of synthetic processes with natural ones, etc. The application of enzymes for waste management has been an environmentally reliable and sustainable process. Treatment of waste with enzymes such as xylanase, proteases, hydrolases, cellulose, peroxidases, chitinases, laccases, etc. has been studied to be effective. These enzymes act upon the waste products and transform them into biodegradable forms that can be recycled, reused and converted to value-added products. They have wide applications and utility as it has been an effective approach, economically cheaper and sustainable techniques. Application of such enzymes for waste management would be beneficial for reducing the quantity of waste, diminishing the negative effects of waste and pollution on the environment, and would be beneficial in bio-converting the waste products into alternate sources of energy. The current chapter focuses on different types of enzymes, their applications for waste management, and their limitations. This chapter also emphasizes the usage of some prominent microorganisms, their secreted enzymes and their proposed mechanisms of action involved with the degradation of the waste products.
ARTICLE | doi:10.20944/preprints202308.0235.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Myzus persicae; insecticides; resistance monitoring; detoxification enzymes; protective enzymes; metabolic mechanism
Online: 2 August 2023 (13:46:59 CEST)
The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is an economically important pest of crops worldwide. A M. persicae (SEF-R) population from a cabbage field in southeastern China was tested for susceptibilities to 13 insecticides. Compared with the susceptible clone (FFJ-S), extremely high and high-resistance to beta-cypermethrin (324-fold) and imidacloprid (106.9-fold) were detected in SEF-R. More importantly, this is the first report of resistance in field M. persicae population to sulfoxaflor, flupyradifurone, pymetrozine, spirotetramat, flonicamid, and broflanilide in China. The resistance factor decayed to a low level to sulfoxaflor and pymetrozine after 15 generations without any selection pressure. The resistance-related mutations (R81T and kdr) were detected in SEF, conferring target-site resistance to neonicotinoids and pyrethroids, respectively. Biochemistry bioassays confirmed the involvement of monooxygenase enzyme, carboxylesterase, superoxide dismutase and peroxidase in multi-insecticide resistance mechanism. The overexpression of P450s, esterases, and a UDP-glycosyltransferase, might be responsible for the multi-insecticide resistance in SEF-R. The knockdown of CYP6CY3 in SEF-R increased its susceptibility to imidacloprid, thiacloprid, and thiamethoxam, which verified that P450s play vital roles in neonicotinoid metabolism. This study will be helpful for chemical control, as well as for resistance monitoring and management of GPA, in China.
REVIEW | doi:10.20944/preprints202308.2181.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: enzymes; glycosylation; oligosaccharides; glycoderivatives
Online: 31 August 2023 (12:15:05 CEST)
Some of the most recent advances in enzymatic glycosylation processes focused on the production of important bioactive compounds have been analyzed. The applicability of different enzymes such as glycosidases, glycosyltransferases, glycophosphorylases and glycosynthases have been de-scribed around the review article considering their advantages and disadvantages of these biocat-alysts in the stereoselective and regioselective synthesis of different types of glycosylated mole-cules, phenolic and aliphatic alcohols, oligosaccharides, polysaccharides, glycoderivatives, glyco-peptides and glycoproteins with a clear focus on food and pharmaceutical chemistry. Therefore, these approaches combining the use of different catalytic systems, the improvement of tools such as immobilization technology, or chemical or genetic modification to improve the synthesization in the glycosylation process could be a very useful tool in a continuous biotechnological advance.
COMMUNICATION | doi:10.20944/preprints202012.0543.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: SARS-CoV-2; enzymes; virucidal; biocide
Online: 21 December 2020 (19:10:09 CET)
Prevention practices have been extensively used to contain the spread of the SARS-CoV-2 virus. These include social distancing, wearing masks, disinfection of hands, and sanitization of contact surfaces. However, the excessive usage of chemical disinfectants pose long term adverse effects to human health and the environment. Development of effective and environmentally friendly biocides, or virucidal agents, will help mitigate the ill effects of chemical disinfectants. Enzymes are potential candidates for the preparation of biocides against bacteria and viruses. Exploration of the virucidal activity of commercial enzymes, will highlight prospective, readily available sources for research on enzyme based biocides. In this study, the virucidal effect of some com-mercial enzyme preparations has been investigated against the SARS-CoV-2 virus. Vida Defense (2000 µg/ml), Excellacor (1500 µg/ml), and SEBkinase (3000 µg/ml) reduced SARS-CoV-2 viral ti-ters by ≥1 log CCID50 (≥90%). ImmunoSEB (6000µg/ml) and Peptizyme SP (500µg/ml) reduced the SARS-CoV-2 viral titers by 0.8 log CCID50 (84.2%). The study indicates that enzyme prepara-tions offer the potential to be explored further for an anti-viral biocide against SARS‐CoV‐2 for reducing the risk of COVID‐19 transmission. However, further studies are mandated to improve efficacy and establish safety.
ARTICLE | doi:10.20944/preprints201908.0314.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: brucellosis; elevated liver enzymes; hepatomegaly; children
Online: 29 August 2019 (17:22:42 CEST)
Background and Objective: In the present study, the purpose was to compare the demographic, clinical and laboratory results of pediatric brucella cases who had liver involvement and who had no specific organ involvement. Material and Methods: The data of 248 patients between 2 and 18 years of age diagnosed with Brucellosis between July 2017 and August 2018 were analyzed retrospectively. The patients who had liver involvement and who did not have other specific organ involvement were compared in terms of presentation, physical examination findings, age, gender, hemogram, AST, ALT, GGT, ALP, bilirubines, sedimentation, CRP, clinical and laboratory findings, and culture and relapse rates. Results: No significant differences were detected between the patients who had liver involvement (n=92) and who did not have specific organ involvement (n=156) in terms of diagnosis age and gender. Loss of appetite, nausea and sensitive stomach were higher in the patients who had hepatic involvement, and weariness was determined to be more in the control group patients. In the patients who had hepatic involvement, the hemoglobin and platelet values were lower, and the sedimentation, CRP and blood culture growth were higher. The relapse rates were lower in patients who had liver involvement. Conclusion: In patients who have liver involvement, in addition to elevated hepatomegaly and transaminase levels, the growth rate of the acute-phase reactants and brucella is higher in blood culture; and the relapse rate is lower after treatment. Brucellosis must be considered in the differential diagnosis of hepatomegaly and transaminase elevation where brucellosis is seen endemically. We believe that early diagnosis of brucellosis is important in treatment response.
REVIEW | doi:10.20944/preprints201801.0198.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: extromphiles; extremophilic bacteria; enzymes; biotechnology application
Online: 22 January 2018 (10:22:21 CET)
Extremophilic bacteria are important groups of extremophilic organisms that have been studied during the last years. They are considered as a source of enzymes due to great diversity and can survive under extreme conditions. Many enzymes produced by these microorganisms are of great importance and have found applications in several industries. Due to their activity and stability under extreme conditions, these enzymes offer new alternatives for current biotechnological and industrial applications. They have a wide range of potential uses and have been a nuclear subject of many different investigations. To date, some of the enzymes produced by extremophilic bacteria are currently being assessed thier industrials applications. Despite, benefits that present these enzymes, their potentials remain largely unexplored. These enzymes pose new opportunities for new line of research, and biotechnological applications. This review provides a summary on diversity and biotechnological and industrial applications of some enzymes produced by extremophilic bacteria.
ARTICLE | doi:10.20944/preprints202308.1629.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: piglets rearing; pancreatic-like enzymes (PLEM); IUGR
Online: 24 August 2023 (03:21:30 CEST)
The present study aimed to develop a feeding strategy for pregnant sows which involved the prenatal administration of a mixture of pancreatic-like fungal enzymes, such as lipase, amylase, and protease, at (1) 1–115 days of gestation (group D1) and (2) 80–115 days of gestation (group D2) and to carry out a comparison with groups of sows that were not receiving such supplementation (negative control [NC] and positive control [PC]). It was found that the administration of the enzyme supplement resulted in a significant shortening of gestation (P ≤ 0.01). The pancreatic enzymes administered to sows had a significant effect on the number of liveborn piglets and weaned piglets, which was higher compared to the control groups that did not receive supplementation respectively: D1-12.1±1.1 and 11.12±1.1; D2- 12.8±1.3 and 11.75±0.07 vs. control groups KN-10.7±1.0 and 9.62±0,95 and KP 10.9±1.2 and 10.15±1.0 (P<0.006). Significant changes in piglet growth were observed after weaning up to 70 days of age. During this period, the most favorable growth parameters were found in groups D2 (420±91g) and PC (407±103g), in which piglets were given a mixture of pancreatic enzymes (lipase, amylase, and protease) at 3 weeks of age, and significantly higher weight gain and feed intake were observed compared to groups NC (378±114g) and D1 (381±96g) (P ≤ 0.007). In contrast, insulin levels were significantly lower in groups D1 and D2, respectively 6,8 IU/ml and 6,7 IU/ml compared to groups NC (14,6 IU/ml) and PC (16,6 IU/ml) ( (P ≤ 0.01). Piglets in group D2 had a significantly better feed conversion ratio (FCR) 1.604±0.10 compared to the other dietary groups: KN– 1.986±0.14; KP– 1.704±0.11; D1 – 1.932±0.15 (P ≤ 0.03). Histological imaging confirmed significantly thicker intestinal epithelium and intestinal mesenteron in animals from groups D2 and PC (P ≤ 0.03). Animals from the groups KP, D1 and D2 receiving enzymes showed a highly significant increase in the surface area of pancreatic follicles and pancreatic surface area compared to the group without KN supplementation (P<0.01). Furthermore, significantly higher activity of the brush border enzyme lactase was observed in groups D1; D2 and PC compared, respectively 32.90±3.99; 30.00±6.83 and 29.60±29.60 to group NC – 21.80± 3.27 (P ≤ 0.01).
REVIEW | doi:10.20944/preprints202012.0492.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Biophysics; Spectroscopy; Physical Chemistry; Enzymes; Bioinorganic Chemistry
Online: 21 December 2020 (10:22:18 CET)
Earth-abundant transition metals like iron, nickel, copper, molybdenum, and vanadium have been identified as essential constituents of the cellular gas metabolism in all kingdoms of life. Associated with biological macromolecules, gas-processing metalloenzymes (GPMs) are formed that catalyse a variety of redox reactions. This includes the reduction of O2 to water by cytochrome c oxidase (‘complex IV’), the reduction of N2 to NH4 by nitrogenase, as well as the reduction of protons to H2 (and oxidation of the later) by hydrogenase. GPMs perform at ambient temperature and pressure, in the presence of water, and often extremely low educt concentrations, thus serving as natural examples for efficient catalysis. Facilitating the design of biomimetic catalysts, biophysicist thrive to understand the reaction principles of GPMs making use of various techniques. In this perspective, I will introduce Fourier-transform infrared spectroscopy in attenuated total reflection configuration (ATR FTIR) for the analysis of GPMs like cytochrome c oxidase, nitrogenase, and hydrogenase. Infrared spectroscopy provides information about the geometry and redox state of the catalytic cofactors, the protonation state of amino acid residues, the hydrogen-bonding network, and protein structural changes. I developed an approach to probe and trigger the reaction of GPMs by gas exchange experiments, exploring the reactivity of these enzymes with their natural reactants. This allows recording sensitive ATR FTIR difference spectra with seconds time resolution. Finally yet importantly, infrared spectroscopy is an electronically non-invasive technique that allows investigating protein samples under biologically relevant conditions, i.e., at ambient temperature and pressure, and in the presence of water.
REVIEW | doi:10.20944/preprints201911.0351.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: solid state fermentation; phenolic compounds; enzymes; polysaccharides
Online: 28 November 2019 (03:43:28 CET)
Solid state fermentation (SSF) is considered more sustainable than traditional fermentation because it uses low amounts of water and transforms agro-industrial residues into value added products. Enzymes, biofuels, nanoparticles and bioactive compounds can be obtained from SSF. The key factor in SSF processes is the choice of microorganisms and their substrates. Many fungal species can be used and are mainly used due their lower requirements of water, O2 and light. Residues rich in soluble and insoluble fiber are utilized by lignocellulolytic fungi because they have the enzymes that break fiber hard structure (lignases, celullases or hemicelullases). During the hydrolysis of lignin, some phenolic compounds are released but fungi also synthetize compounds such as mycophenolic acid, dicerandrol C, phenylacetates, anthraquinones, benzofurans and alkenyl phenols that have health beneficial effects such as antitumoral, antimicrobial, antioxidant and antiviral activities. Another important group of compounds synthetized by fungi during fermentation are polysaccharides that also have important health promoting properties. Fungal biofermentation has also proved to be a process which can release high contents of phenolics and it also increases the bioactivity of these compounds.
ARTICLE | doi:10.20944/preprints201902.0124.v4
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: enzymes Cyclooxygenase, ligand, metabolites, antiinflammatory, Molecular Docking
Online: 29 May 2019 (11:39:02 CEST)
Cyclooxygenases (COX), or prostaglandin endoperoxide synthases (PTGS), are key enzimes in the synthesis of prostaglandins, which are chemical species critical in mediating inflammatory processes. There are two highly homologous COX isoforms: COX-1 and COX-2. COX-1 is involved in the production of prostaglandins, chemical compuounds that take part in physiological processes such as: protection of the gastric epithelium, maintenance of renal flow, platelet aggregation, neutrophil migration and, also, are expressed in the vascular endothelium. Meanwhile, COX-2 is induced by proinflammatory stimuli. It is very frequent the use of nonsteroidal antiinflammatory drugs (NSAIDs) to counteract the symptoms of inflammatory processes. These drugs, in addition to its benefits, can cause side effects on people’s health, such as cardiovascular and respiratory problems, among others. In the past years, it has been recognized the potential of plants secondary metabolites as pharmacological agents, prompting the need for investigations that shed light into its mechanism of action. In this work we have applied computational techniques, based on quantum chemistry and mechanical statistics, to study the protein-ligand interaction involving COX’s and secondary metabolites from natural sources. Our aim is to determine the structure activity interplay in processes involving the participation of secondary plant metabolites such as luteolin, galangin, kaempferol, apigenin, morine and quercetin on the inactivation of COX’s. From molecular docking analysis, we have extracted the energetics of the COX-(1,2)/metabolite coupling. By defining energy based factors, we have determined a procedure that predicts the chemical species with highest stability and selectivity towards inactivation of COX-2 over COX-1. The results are discussed with regard to conformational features of the selected ligands and its intermolecular strong/weak interactions inside the active-sites of the COX’s hosts.
ARTICLE | doi:10.20944/preprints201808.0428.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: thermo-responsive; ultrafiltration; enzymes; self-cleaning; nanofibers
Online: 24 August 2018 (07:52:04 CEST)
Controlling surface-protein interaction during wastewater treatment is the key motivation for developing functionally modified membranes. A new biocatalytic thermo-responsive poly(vinylidene fluoride)(PVDF)/nylon-6,6/poly(N-isopropylacrylamide)(PNIPAAm) ultrafiltration membrane was fabricated to achieve dual functionality of protein-digestion and thermo-responsive self-cleaning. The PVDF/nylon-6,6/PNIPAAm composite membranes were constructed by integrating a hydrophobic PVDF cast layer and hydrophilic nylon-6,6/PNIPAAm nanofiber layer where trypsin enzymes were covalently immobilized. The immobilization density of enzymes on the membrane surface decreased with increasing PNIPAAm concentration, due to the decreased number of amine functional sites. Through a ultrafiltration study using a model solution containing BSA/NaCl/CaCl2, the PNIPAAm containing biocatalytic membranes demonstrated a combined effect of enzymatic and thermo-switchable self-cleaning. The membrane without PNIPAAm revealed superior fouling resistance and self-cleaning with an RPD of 22%, compared to membranes with 2 and 4 wt% PNIPAAm with 26% and 33% RPD, respectively, after an intermediate temperature cleaning at 50°C, indicating that higher enzyme density offers more efficient self-cleaning than the combined effect of enzyme and PNIPAAm at low concentration. The conformational volume phase transition of PNIPAAm did not affect the stability of immobilized trypsin on membrane surface. Such novel surface engineering design offer a promising route to severe surface-protein contamination remediation in food and wastewater applications.
REVIEW | doi:10.20944/preprints201703.0118.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: dengue; chikungunya; virus enzymes; antiviral; natural products
Online: 16 March 2017 (09:42:52 CET)
Dengue virus (DENV) and chikungunya virus (CHIKV) are reemergent arboviruses that are transmitted by mosquitoes of the Aedes genus. During the last several decades, these viruses have been responsible for millions of cases of infection and thousands of deaths worldwide. Therefore, several investigations were conducted over the past few years to find antiviral compounds for the treatment of DENV and CHIKV infections. One attractive strategy is the screening of compounds that target enzymes involved in the replication of both DENV and CHIKV. In this review, we describe advances in the evaluation of natural products targeting the enzymes involved in the replication of these viruses.
REVIEW | doi:10.20944/preprints201807.0432.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Seed coat; pericarps; floral bracts; glumes; dead organs enclosing embryos; seed germination; seedling establishment; hydrolytic enzymes; ROS detoxifying enzymes; cell wall modification enzymes; nutrients; phytohormones; nucleases; chitinases; Brassicaceae; Poaceae
Online: 26 July 2018 (09:53:41 CEST)
Plants have evolved a variety of dispersal units whereby the embryo is enclosed by various dead protective layers derived from maternal organs of the reproductive system including seed coats (integuments), pericarps (ovary wall, e.g., indehiscent dry fruits) as well as floral bracts (e.g. glumes) in grasses. Commonly, dead organs enclosing embryos (DOEEs) are assumed to provide a physical shield for embryo protection and means for dispersal in the ecosystem. In this review article, we will highlight recent studies showing that DOEEs of various species across families also have the capability for long-term storage of various substances including active proteins (hydrolases, ROS detoxifying enzymes), nutrients and metabolites that have the potential to support the embryo during storage in the soil and assist in germination and seedling establishment. We discuss a possible role for DOEEs as natural coatings capable of ‘engineering’ the seed microenvironment for the benefit of the embryo, the seedling and the growing plant.
ARTICLE | doi:10.20944/preprints202309.1111.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: thraustochytrids; molasses; extracellular enzymes; Aurantiochytrium; lipid; fatty acids
Online: 18 September 2023 (04:48:55 CEST)
The production of oil by thraustochytrids is still costly because of its necessary and expensive culture medium. We evaluated the growth, lipid production, and fatty acid composition in an inexpensive, molasses-based (M) medium. Newly isolated thraustochytrid strains were identified as members of genus Aurantiochytrium based on 18S rRNA gene sequences. Isolated strains were repeatedly cultured in M medium for acclimatization to the medium. Acclimatized and non-acclimatized strains were cultured in basal GY medium and M medium. The lipid in the cultured cells were extracted by the Folch method, and the fatty acid composition was analyzed by gas chromatograph. The growth and lipid production in the non-acclimatized strains were significantly inhibited by culturing in M medium, whereas the growth and lipid production were improved by acclimatization treatment in the same medium. The fatty acid composition in the cultured cells were affected by the M medium compared to the basal GY medium. The production of some enzymes such as leucine and valine aryl-amidase was suppressed in the M medium, and the activities recovered by acclimatization treatment. The growth of some strains in the molasses medium was thus recovered by the acclimatization process, and the profiles of extracellular enzymes were also affected.
ARTICLE | doi:10.20944/preprints202302.0255.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: Aspartylglucosaminuria; lysosomal storage disorders; biomarkers; protein glycosylation; enzymes
Online: 15 February 2023 (07:54:15 CET)
Novel treatment strategies are emerging for rare, genetic diseases, resulting in clinical trials that require adequate biomarkers for the assessment of the treatment effect. For enzyme defects, biomarkers that can be assessed from patient serum, such as enzyme activity, are highly useful, but the activity assays need to be properly validated to ensure a precise, quantitative measurement. Aspartylglucosaminuria (AGU) is a lysosomal storage disorder caused by the deficiency of the lysosomal hydrolase aspartylglucosaminidase (AGA). We have here established and validated a fluorometric AGA activity assay for human serum samples from healthy volunteers and AGU patients. We show that the validated AGA activity assay is suitable for the assessment of AGA activity in the serum of healthy controls and AGU patients, and it can be used for diagnostics of AGU and, potentially, for following a treatment effect.
REVIEW | doi:10.20944/preprints202207.0309.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: ubiquitin; E3 ligase; chloroplast; stress; photosynthesis; homeostasis; enzymes
Online: 21 July 2022 (03:20:20 CEST)
Chloroplasts are ancient organelles responsible for photosynthesis and various biosynthetic functions essential to most life on Earth. Many of these functions require tightly controlled regulatory processes to maintain homeostasis at the protein level. One such regulatory mechanism is the ubiquitin-proteasome system whose fundamental role is increasingly emerging in chloroplasts. In particular, the role of E3 ubiquitin ligases as determinants in the ubiquitination and degradation of specific intra-chloroplast proteins. Here, we highlight recent advances in understanding the roles of plant E3 ubiquitin ligases in chloroplast function.
ARTICLE | doi:10.20944/preprints202103.0735.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: antioxidant enzymes; pharmaceutical residues; pesticides; detergents; integrative indexes
Online: 30 March 2021 (12:26:28 CEST)
Worldwide anthropogenic activities result in the production and release of poten-tially damaging toxic pollutants into ecosystems, thereby jeopardizing their health and continuity. Research studies and biomonitoring programs attend to this emerging problematic by applying and developing statistically relevant indexes that integrate complex biomarker response data to provide an holistic approach reflecting toxically induced alterations at the organism’s or population level. Ultimately, indexes allow simple result communication, enhancing policy makers understanding, so contributing for better resource and environmental managing policies. In this study three indexes , the Integrated Biomarker Response index (IBR), the Bioeffects Assessment Index (BAI) and the Principal Components Analysis (PCA), were evaluated for their sensitivity in revealing toxically induced stress patterns in cells of the diatom Phaeodactylum tricornutum under contaminant exposure. The set of biomarkers selected for index construction comprise the anti-oxidant enzymes APX, CAT and SOD, and the lipid peroxidation marker TBARS. Several significant inverse correlations with the concentration gradients applied, , was noticed for all indexes, though, the IBR excels for its reliability in delivering statistically significant dose-response patterns for four out of the five compounds tested.
ARTICLE | doi:10.20944/preprints202101.0618.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Newcastle disease virus; chicken; pancreas; hormone; enzymes; histopathology
Online: 29 January 2021 (12:38:05 CET)
Newcastle disease virus (NDV) causes a highly contagious and devastating disease in poultry, Newcastle disease (ND). ND causes heavy economic losses to the global poultry industry by decreasing the growth rate, decrease egg productions, mortality, and morbidity. Although, significant advances have been made in the vaccine development, but outbreaks are reported in vaccinated birds leading to overall decreased growth rate. In this study, we report the damage caused by the NDV infection in the pancreatic tissues of vaccinated as well as specific pathogen free chickens. The histopathological examination of the pancreas showed sever damage in the form of partial depletion of zymogen granules, acinar cell vacuolization, necrosis, and apoptosis, congestion in the large and small vessels, sloughing of epithelial cells of pancreatic duct, and mild perivascular edema. Increased plasma levels of corticosterone, somatostatin, were observed in NDV infected chicks at 3 and 5-day post infection (DPI). Slight decrease in the plasma concentrations of the insulin were noticed at 5 DPI. Significant changes were not observed in the plasma levels of glucagon. Furthermore, NDV infection has decreases the activity and mRNA expression of amylase, lipase, and trypsin from the pancreas. Taken together, our findings highlight that NDV induces extensive tissue damage in pancreas, decrease the activity and expression of pancreatic enzymes and increase plasma corticosterone and somatostatin.
ARTICLE | doi:10.20944/preprints202009.0231.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: organic acids; sugars; anthocyanins; antioxidant enzymes; ascorbic acid
Online: 10 September 2020 (09:11:16 CEST)
The changes in nutritional quality, bioactive compounds and antioxidant enzymes in the juice of four blood orange cultivars (‘Moro’, ‘Tarocco’, ‘Sanguinello’ and ‘Sanguine’) stored during 6 months at 2 and 5 °C plus 2 days at 20 °C for shelf life were studied. Sucrose was the sugar found at higher concentration and decreased during storage for all cultivars, as did glucose and fructose. Organic acids decreased at both temperatures and the highest content was found in ‘Sanguinello’, especially the major (citric acid) and ascorbic acid. Total phenolics content (TPC), total anthocyanins (TAC), and the individual (cyanidin 3-glucoside and cyanidin 3-(6″-malonylglucoside)) increased for all cultivars, the ‘Sanguinello’ having the higher concentrations. Antioxidant enzymes catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) were higher also in ‘Sanguinello’ and increased during storage. Overall, these results together with the sensory analysis suggest that ‘Sanguinello’ would be the best cultivar for prolonged storage.
Subject: Biology And Life Sciences, Toxicology Keywords: chromerids; transcriptome; heavy metal; antioxidant enzymes; xenobiotics; phylogenies
Online: 21 September 2019 (09:46:22 CEST)
Heavy metal pollution is an increasing global concern. Among heavy metals, mercury (Hg) is especially dangerous because of its massive release into the environment and high toxicity, especially for aquatic organisms. The molecular response mechanisms of algae to Hg exposure are mostly unknown. Here, we combine physiological, biochemical, and transcriptomic analysis to provide, for the first time, a comprehensive view on the pathways activated in Chromera velia in response to toxic levels of Hg. Production of hydrogen peroxide and superoxide anion, two reactive oxygen species (ROS), showed opposite patterns in response to Hg2+ while reactive nitrogen species (RNS) levels did not change. A deep RNA sequencing analysis generated a total of 307,738,790 high-quality reads assembled in 122,874 transcripts, representing 89,853 unigenes successfully annotated in databases. Detailed analysis of the differently expressed genes corroborate the biochemical results observed in ROS production and suggests novel putative molecular mechanisms in the algal response to Hg2+. Moreover, we indicated that important transcription factor (TF) families associated with stress responses differentially expressed in C. velia cultures under Hg stress. Our study presents the first in-depth transcriptomic analysis of C. velia, focusing on the expression of genes involved in different detoxification defense systems in response to heavy metal stress.
ARTICLE | doi:10.20944/preprints201806.0306.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Keywords: Bacillus amyloliquefaciens, Chitinase, Defense enzymes; Biological control
Online: 19 June 2018 (15:56:47 CEST)
To investigate whether the ech42 gene in Clonostachys rosea can improve the biocontrol efficacy of Bacillus amyloliquefaciens and its molecular mechanism.Compared to the wild type, the B. amyloliquefaciens transformed with the ech42 gene exhibited a higher chitinase activity. The B. amyloliquefaciens-ech42 also showed a significantly higher biocontrol efficiency against B. cinerea when tomato plants were pre-treated with amyloliquefaciens-ech42. No significant difference of control efficiency was observed between the wild type and amyloliquefaciens-ech42 when tomato plants were first infected by B. cinerea. In addition, the activity of the defense-related enzyme polyphenol oxidase, but not superoxide dismutase was significantly higher in amyloliquefaciens-ech42 than in the wild type.The ech42 enhances the Bacillus amyloliquefaciens biocontrol efficiency by increasing the capacity of protection/prevention to plants, rather treating/killing the pathogens.
REVIEW | doi:10.20944/preprints202309.1436.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: Cobalt; toxicity; plants; detoxification; micronutrient; macronutrients; anti-oxidative enzymes
Online: 21 September 2023 (09:53:29 CEST)
Cobalt (Co) is a transition metal and is classified as a beneficial metal for plants, but its benefits for plants remain obscure. Cobalt has been reported to negatively affect plant physiochemical processes both at higher (toxic) and lower (deficient) applied levels. High concentrations of cobalt in plant organs cause irreversible changes to the plant cells, mainly via enhanced production of reactive radicals. Moreover, Co and its compound play an essential role in humans as they are the central atoms of cobalamin, a co-enzyme precursor whose absence causes anemia. Hence, the optimum Co supply to plants is critical for customary plant metabolic workings. Henceforth, monitoring Co behavior in the soil-plant-human system is highly imperative. This review highlighted the latest literature on (i) Co in soil and plants; (ii) its mobility and phyto-availability in soil; (iii) phytouptake and translocation towards shoot tissues; (iv) toxic and deficient effects of Co on plants; (v) plant detoxification mechanisms under increased Co levels inside plants; and (v) its role in the human body. For this purpose, 1026 plant observations from literature data were analyzed related to Co biogeochemical behavior in the soil-plant system. The data analysis revealed an overall increase in 567 observations and a decrease in 381 observations. However, these general trends in plant responses vary significantly for different types of plant species and physiological attributes. Overall, the current review delineates an updated and critical representation of the biogeochemical behavior of Co in the soil-plant-human system, supported by up-to-date 9 main tables, 14 supporting tables, and 3 figures. The authors believe that the literature presented here can be of great interest to scientists, researchers, policymakers, and graduate-level students.
ARTICLE | doi:10.20944/preprints202308.0396.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: salt stress; photosynthesis; antioxidant enzymes; ROS scavenging; Meyerozyma guilliermondii
Online: 4 August 2023 (12:38:03 CEST)
How to improve plant tolerance and yield under salt stress is critical for ensuring sufficient food supply since plant survival and agricultural productivity are both affected by salinity. Some evidence has showed that beneficial microorganisms have a high ability to improve plant salt tolerance and increase crop yield. But few studies were involved in effects of halotolerant yeasts on plants under salt stress. In this present research, Meyerozyma guilliermondii, a halotolerant yeast, was inoculated with tomato plants followed by salt treatment of four different NaCl concentrations (0, 100, 200, and 300 mM). Our results showed that inoculation of M. guilliermondii increased the chlorophyll biosynthesis and photosynthetic machinery effectiveness under salt stress, contributing to biomass accumulation. Under salt treatment of 300 mM NaCl, the yeast inoculation significantly increased ascorbate concentrations in leaves, yet showed no effects on levels of glutathione and proline. Antioxidant enzymes were affected differently by the yeast inoculation. It was found that the yeast inoculation increased superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities under 300, 100, and 200 mM NaCl, respectively. Total soluble sugar levels increased in inoculated tomato plant leaves; however, there were no significant differences between different NaCl concentrations. Under 300 mM NaCl, the yeast inoculation significantly decreased H2O2 levels and reduced malondialdehyde levels. All together, our results showed that halotolerant yeast M. guilliermondii inoculation might be a strong candidate for regulating tomato growth under salt stress by increasing ability to scavenge reactive oxygen species and chlorophyll intactness, and by strengthening photosynthetic machinery.
ARTICLE | doi:10.20944/preprints202306.1587.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: lichen; UV-induced melanization; melanin; topography; hydrolytic enzymes; microscopy
Online: 22 June 2023 (10:14:23 CEST)
Lichens are unique extremophilic organisms due to their phenomenal resistance to adverse environmental factors, including ultraviolet (UV) irradiation. Melanization plays a special role in the protection of lichens from UV-B stress. In present study, we analyzed the binding of melanins with the components of cell walls of mycobiont of upper cortex in the melanized lichen thalli Lobaria pulmonaria. Using scanning electron and atomic force microscopy, the morphological and nanomechanical characteristics of melanized layer of mycobiont cells were visualized. Melanization of lichen thalli led to the smoothing the surface relief and thickening mycobiont cell walls and resulted in the increase of deformation values and reduction of adhesion properties of lichen thallus. Treatment of thalli with hydrolytic enzymes, especially chitinase and lichenase, enhanced the yield of melanin from melanized thalli and release of carbohydrates, while treatment with pectinase increased the release of carbohydrates and phenols. Our results suggest that melanin by firmly binding with hyphal cell wall carbohydrates, particularly chitin and 1,4-β-glucans, can form associations, strengthen the melanized upper cortex of lichen thalli, and thereby can contribute to lichen survival under UV stress.
ARTICLE | doi:10.20944/preprints202305.2067.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Metagenomics; red algae; microbial diversity; algal-polysaccharide-degrading enzymes
Online: 30 May 2023 (07:33:37 CEST)
Macroalgae and macroalgae-associated bacteria together constitute the most efficient metabolic cycling system in the ocean. Their interactions, especially the responses of macroalgae-associated bacteria communities to algae in different geographical locations, is mostly unknown. In this study, metagenomics was used to analyze the microbial diversity and associated algal polysaccharide-degrading enzymes on the surface of red algae among three remote regions. There were significant differences in the macroalgae-associated bacteria community composition and diversity among the different regions. At the phylum level, Proteobacteria, Bacteroidetes, and Actinobacteria had a significantly high relative abundance among the regions. From the perspective of species diversity, samples from China had the highest macroalgae-associated bacteria diversity, followed by those from Antarctica and Indonesia. In addition, in the functional prediction of the bacterial community, genes associated with amino acid metabolism, carbohydrate metabolism, energy metabolism, metabolism of cofactors and vitamins, and membrane transport had a high relative abundance. Canonical correspondence analysis and redundancy analysis of environmental factors showed that, without considering algae species and composition, pH and temperature were the main environmental factors affecting bacterial community structure. Furthermore, there were significant differences in algal polysaccharide-degrading enzymes among the regions. Samples from China and Antarctica had high abundances of algal polysaccharide-degrading enzymes, while those from Indonesia had extremely low abundances. The environmental differences between these three regions may impose a strong geographic differentiation regarding the biodiversity of algal microbiomes and their expressed enzyme genes. This work expands our knowledge of algal microbial ecology, and contributes to an in-depth study of their metabolic characteristics, ecological functions, and applications.
COMMUNICATION | doi:10.20944/preprints202305.0667.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: Suzuki-Miyaura reaction; biomimetic thioesters; polyketide synthases; enzymes; cyclases
Online: 9 May 2023 (14:32:34 CEST)
Biomimetic N-acetylcysteamine thioesters are essential for the study of polyketide synthases, non-ribosomal peptide synthetases and fatty acid synthases. The chemistry for their preparation is however limited by their specific functionalization and their susceptibility to undesired side reactions. This is especially detrimental to transition metal-catalyzed reactions. Here we report a method for the rapid preparation of N-acetylcysteamine (SNAC) 7-hydroxy-2-enethioates, which are suitable for the study of various enzymatic domains of megasynthase enzymes, particularly oxygen heterocycle-forming cyclase domains. The method is based on a one-pot sequence of hy-droboration and Suzuki-Miyaura reaction. Optimization of the reaction conditions made it possi-ble to suppress potential side reactions and to introduce the highly functionalized SNAC meth-acrylate unit in high yield. The versatility of the sequence was demonstrated on a dienal precur-sor, which was subjected to Brown crotylation followed by the hydroboration-Suzuki-Miyaura reaction sequence and deprotection, finally giving a complex polyketide SNAC thioester. Back-bone extension by six carbons and a terminal SNAC enethioate was achieved, introducing an E-configured double bond and two adjacent stereocenters in a highly selective manner. The pre-sented method allows for the synthesis of the target motif in significantly fewer steps and with higher overall yield than previously described approaches, while maintaining higher flexibility and control over the stereogenic elements. It is also the first reported example of a transition met-al-catalyzed cross-coupling reaction in the presence of an SNAC thioester.
ARTICLE | doi:10.20944/preprints202301.0100.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Antarctic fish; antioxidant enzymes; oxidative stress; gene expression; PFAS
Online: 5 January 2023 (04:50:42 CET)
Antarctica is the continent with the lowest local human impact, yet it is still vulnerable to contaminants coming from external sources. Emerging pollutants, like PFAS, pose an increasing threat to this environment and therefore require more in-depth investigations to understand their environmental fate and biological impacts. The present study, part of the AntaGPS project, focuses on expression analysis at the transcriptional level of genes coding for 4 antioxidant enzymes (sod1, sod2, gpx1, gpx4) in different organs of an Antarctic fish species, Trematomus newnesi. The kidney showed a higher level of expression than the liver of wildlife specimens. The mRNA levels were also assessed in fish exposed to 1.5 μg/L of PFOA for 10 days. In the liver, the treatment induced an increase in gene expression for all the considered enzymes, while in the kidney it induced a general decrease. The obtained results constitute a starting point for using the expression of antioxidant enzymes as biomarkers, both of oxidative stress and exposure to PFAS, in future biomonitoring campaigns in the Antarctic marine environment.
ARTICLE | doi:10.20944/preprints202205.0154.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: antioxidant enzymes; freshwater fish; oxidative stress; PFAS; Veneto region
Online: 12 May 2022 (02:47:28 CEST)
In recent decades, the interest in PFAS has grown exponentially around the world, due to the toxic effects induced by these chemical compounds in humans, as well as in other animals and in plants. However, current knowledge related to the antistress responses that organisms can express when exposed to these substances is still insufficient and therefore it requires further investigation. The present study focuses on antioxidant responses in Squalius cephalus and Padogobius bonelli, exposed to significant levels of PFAS in an area of the Veneto region subjected to a recent relevant pollution case. These two ubiquitous freshwater species were sampled in three rivers characterized by different concentrations of PFAS. Several biomarkers of oxidative stress have been evaluated and the results suggest that PFAS chronic exposure induces some physiological responses in the target species, at both cellular and tissue scales. The risk of oxidative stress seems to be kept under control by the antioxidant system by means of gene activation at the mitochondrial level. Moreover, the histological analysis suggests an interesting protective mechanism against damage to the protein component based on lipid vacuolization.
REVIEW | doi:10.20944/preprints202009.0696.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Beauveria bassiana; cuticle degrading enzymes; entomopathogenic fungi; pathogenesis; virulence
Online: 29 September 2020 (08:57:33 CEST)
Intensive crop production and extensive use of harmful synthetic chemical pesticides create numerous socio-economic problems worldwide. Therefore, sustainable solutions are needed for insect pest control, such as biological control agents. The fungal insect pathogen Beauveria bassiana has shown considerable potential as a biological control agent against a broad range of insects. The insights into virulence mechanism of B. bassiana is essential to show the robustness of its use. B. bassiana has several determinants of virulence, including the production of cuticle-degrading enzymes (CDEs), such as proteases, chitinases, and lipases. CDEs are essential in the infection process as they hydrolyze the significant components of the insect's cuticle. Moreover, B. bassiana has evolved effective antioxidant mechanisms that include enzyme families that act as ROS scavengers, e.g., superoxide dismutases, catalases, peroxidases, and thioredoxins. In B. bassiana, the number of CDEs and antioxidant enzymes characterized in recent years. The enzymatic activities are crucial for the biological control potential and significantly advanced our understanding of the infection mechanism of B. bassiana. This review focuses on the progress detailed in the studies of these enzymes and provides an overview of enzymatic activities and their contributions to virulence.
ARTICLE | doi:10.20944/preprints202312.0482.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: Durvillaea incurvata; aging; enzymes inhibition; Alzheimer's, diabetes; hypertension
Online: 7 December 2023 (07:12:27 CET)
World population is in a demographic transition, with an increase in number of older adults and prevalence of diseases related to aging. This study evaluated in vitro the potential of an ultrasound-assisted extract from Durvillaea incurvata to inhibit key enzymes associated with development of age-related diseases. Results show that an ultrasound-assisted extract as well as conventional extract from Durvillaea incurvata presented anti-diabetes potential by exhibiting inhibitory activity against α-glucosidase enzymes (91.8 ± 1.0 % and 93.8 ± 0.3 % respectively, at 500 µg/mL) and α-amylase (42.2 ± 1.4 % and 61.9 ± 0.9 % respectively, at 1500 µg/mL), related to starch digestion and postprandial glycemic response. Also, extracts presented inhibitory activity on the enzyme acetylcholinesterase (51.5% and 50.8% respectively, at 500 µg/mL) and butyrylcholinesterase (32.8% and 34.4% respectively, at 0.5 mg /mL), biomarkers associated with Alzheimer's disease, and showed inhibitory activity against angiotensin-I converting enzyme (98.7 ± 7.4% and 93.0 ± 3.4% respectively, at 2.0 mg /mL), key in the regulation of vascular tone and blood pressure, which helps to prevent the development of hypertension. In conclusion, the ultrasound-assisted extract of Durvillaea incurvata has the potential to prevent the development of age-related pathologies, such as diabetes, Alzheimer's disease, and hypertension.
ARTICLE | doi:10.20944/preprints202308.2207.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Streptococcus suis; Serotype 2; North America; Lipoprotein maturation enzymes; Inflammation
Online: 1 September 2023 (07:16:13 CEST)
Streptococcus suis serotype 2 is an important swine bacterial pathogen causing sudden death, septic shock, and meningitis. However, serotype 2 strains are phenotypically and genotypically heterogeneous and composed by a multitude of sequence types (STs) whose distribution greatly varies worldwide. It has been previously shown that lipoprotein (LPP) maturation enzymes diacylglyceryl transferase (Lgt) and signal peptidase (Lsp) significantly modulate the inflammatory host response and play a differential role in virulence depending on the genetic background of the strain. Differently from Eurasian ST1/ST7 strains, the capsular polysaccharide of a North American S. suis serotype 2 ST25 representative strain only partially masks sub-capsular domains and bacterial wall components. Thus, our hypothesis is that since LPPs would be more surface exposed in ST25 strains than in their ST1 or ST7 counterparts, the maturation enzymes would play a more important role in the pathogenesis of the infection caused by the North American strain. Using isogenic Δlgt and Δlsp mutants derived from the wild-type ST25 strain, our studies suggest that these enzymes do not seem to play a role in the interaction between S. suis and epithelial and endothelial cells, regardless the genetics background of the strain used. However, a role in the formation of biofilms (also independently of the STs) has been demonstrated. Moreover, the involvement of LPP dendritic cell activation in vitro seems to be somehow more pronounced with the ST25 strain. Finally, the Lgt enzyme seems to play a more important role in the virulence of the ST25 strain. Although some differences between STs could be observed, our original hypothesis that LPPs would be significantly more important in ST25 strains due to a better bacterial surface exposition could not be confirmed.
ARTICLE | doi:10.20944/preprints202111.0577.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Ciona robusta; tunicate; metals; typical 2-Cys peroxiredoxins; antioxidant enzymes.
Online: 30 November 2021 (17:58:47 CET)
Typical 2-Cys peroxiredoxins (2-Cys Prdxs) are proteins with antioxidant properties belonging to the thioredoxin peroxidase family. With their peroxidase activity, they contribute to the homeostatic control of reactive oxygen species (ROS) and, therefore, participate in various physiological functions such as cell proliferation, differentiation, and apoptosis. Although Prdxs have been shown to be potential biomarkers for monitoring the aquatic environments, minimal scientific attention has been devoted to describing their molecular architecture and function in marine invertebrates. Our study aims to clarify the protective role against stress induced by exposure to metals (Cu, Zn, and Cd) of three Prdxs (Prdx2, Prdx3, and Prdx4) in the solitary ascidian Ciona robusta, an invertebrate chordate. Here we report a detailed pre- and post-translational regulation of the three Prdx isoforms. Data on intestinal mRNA expression, provided by qRT-PCR analyses, show a generalized increase for Prdx2, 3, and 4, which is correlated to metal accumulation. Furthermore, the increase in tissue enzyme activity observed after Zn exposure is slower than that observed with Cu and Cd. The obtained results increase our knowledge of the evolution of anti-stress proteins in invertebrates and emphasize the importance of the synthesis of Prdxs as an efficient way to face adverse environmental conditions.
ARTICLE | doi:10.20944/preprints202108.0306.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: aminoglycoside resistance; structure-activity relationship; aminoglycoside modifying enzymes, acetyltransferase, Acinetobacter
Online: 14 August 2021 (14:12:06 CEST)
The aminoglycoside 6′-N-acetyltransferase type Ib [AAC(6′)-Ib] is a common cause of resistance to amikacin and other aminoglycosides in Gram-negatives. Utilization of mixture-based combinatorial libraries and application of the positional scanning strategy identified an inhibitor of AAC(6′)-Ib. This inhibitor’s chemical structure consists of a pyrrolidine pentamine scaffold substituted at four locations (R1, R3, R4, and R5). The substituents are two S-phenyl (R1 and R4), an S-hydroxymethyl (R3), and a 3-phenylbutyl (R5) groups. Another location, R2, does not have a substitution, but it is named because its stereochemistry was modified in some compounds utilized in this study. Structure-activity relationship (SAR) analysis using derivatives with different functionalities, modified stereochemistry, and truncations were carried out by assessing the effect of the addition of each compound at 8 µM to 16 µg/ml amikacin-containing media and performing checkerboard assays varying the concentrations of the inhibitor analogs and the antibiotic. The results showed that: 1) the aromatic functionalities at R1 and R4 are essential, but the stereochemistry is essential only at R4, 2) the stereochemical conformation at R2 is critical, 3) the hydroxyl moiety at R3 as well as stereoconformation are required for full inhibitory activity, 4) the phenyl functionality at R5 is not essential and can be replaced by aliphatic groups, 5) the location of the phenyl group on the butyl carbon chain at R5 is not essential, 6) the length of the aliphatic chain at R5 is not critical, 7) all truncations of the scaffold resulted in inactive compounds. Molecular docking revealed that all compounds preferentially bind to the kanamycin C binding cavity, and binding affinity correlates with the experimental data for most of the compounds evaluated. The SAR results in this study will serve as the basis for the design of new analogs in an effort to improve their ability to induce phenotypic conversion to susceptibility in amikacin-resistant pathogens.
ARTICLE | doi:10.20944/preprints202106.0108.v2
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Organic acid; Digestive enzymes; Immune response; Microencapsulation; Vibrio sp.; Shrimp
Online: 7 June 2021 (12:44:12 CEST)
Use of antibiotics and other chemicals to combat disease outbreaks have been a bottleneck for the sustainable growth of shrimp industry. Among various replacement proposed, organic acid (OA) and their salts (OS) are commonly used by farmers and feed millers. However, in free forms, their requirement is very high (2-3 kg/MT) as they tend to disassociate before reaching the hindgut. The dosage can be reduced by microencapsulation of the ingredients. In this study, a 63-day trial was conducted to assess the effects of OA and OS (COMP) microencapsulated (ENCAP) with fat (HF), fat + alginate (HA), wax esters – (WE), and HA and WE (HAWE) on performance, digestive enzyme, immune, and resistance to Vibrio parahaemolyticus. A positive control (PC, 200 g/kg fishmeal - FM) and a negative control (NC, 130 g/kg FM) diet were formulated. Eight other diets were formulated supplementing NC diet with microencapsulated OA (OAHF, OAHA, OAWE, OAHAWE) and OS (OSHF, OSHA, OSWE, OSHAWE). Among the ENCAPs, significant difference was observed in serum malondialdehyde (P = 0.026) where HF showed the lowest level (6.4 ±0.3 mmol/L). Significant interactions between COMP and ENCAP were observed in lipid deposition (P = 0.047), serum alkaline phosphatase and acid phosphatase (P < 0.0001), and hepatopancreatic and serum phenol oxidase (P < 0.0001). Despite no differences, 96-h mortality during pathogenic Vibrio parahaemolyticus challenge in all treatment diets (45% - 56%) was lower compared to the NC diets (63%). In conclusion, use of HF microencapsulated OA diets could provide improved performance and disease resistance that could contribute to the reduction of antibiotic use by the shrimp industry.
ARTICLE | doi:10.20944/preprints202012.0511.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antioxidant enzymes; hemibiotroph; reactive oxygen species; host-pathogen interaction; sporulation
Online: 21 December 2020 (11:23:57 CET)
Wheat blast caused by the hemibiotroph fungal pathogen Magnaporthe oryzae Triticum (MoT) pathotype, is a destructive disease of wheat in South America and Bangladesh. Generation of reactive oxygen species (ROS) is one of the defense responses in plants during the infection process by a pathogen. However, empirical evidence on regulation of ROS in wheat and other host and non-host plants towards MoT is limited. This study aimed to determine the susceptibility of some major cereals and weeds of Bangladesh and compare the antioxidant enzyme activities in host and non-host plants in response to artificial inoculation by MoT. Seedlings of wheat, maize, barley and swamp rice grass were susceptible to MoT and produced considerable number of conidia on infected leaves (host). Rice seedlings showed a resistant response in our laboratory conditions (non-host). The activities of ROS-detoxifying enzymes; catalase (CAT), ascorbate peroxidase (APX), Glutathione peroxidase (GPX), Glutathione S-transferase (GST), Peroxidase (POX) increased in all plants after inoculation by MoT with a few exceptions. Interestingly, an early and very high accumulation of CAT was observed within 24 hours of inoculation (hai) in wheat, barley, maize and swamp rice grass while H2O2 concentration was low during that time and immediately after that (24-48 hai). In contrast, an early and high accumulation of H2O2 was observed in rice at 48 hai with little CAT activity only at a late stage. The APX, GST and POD activity was also increased due to the inoculation of MoT at the early stage of infection in rice but were very high at the disease progression stage in wheat, barley, maize and swamp rice grass. GPX activity gradually decreased with the increase of time in rice. Taken together, our results suggest that a robust and late induction of most of the antioxidant enzyme activities occurs in susceptible/host plants whereas an early induction of antioxidant enzyme activities occurs in resistant/ non-host plant but with slow kinetics.
COMMUNICATION | doi:10.20944/preprints202010.0005.v1
Subject: Medicine And Pharmacology, Other Keywords: Enzymes, Peptide Hydrolases, Metalloproteases, Biomarkers, Gingival Crevicular Fluid, Atopic Dermatitis
Online: 1 October 2020 (08:55:12 CEST)
Atopic dermatitis (AD) is a protease-modulated chronic disorder with heterogenous clinical manifestations which may lead to an imprecise diagnosis. So far, there are no diagnostic protease tests for AD. We explored the gingival crevicular fluid (GCF) protease profile of periodontally-healthy individuals with moderate/severe AD compared to healthy controls. An exploratory case-control study was conducted. Matching AD patients (n=6) and controls (n=6) were enrolled at the International Center for Clinical Studies, Santiago, Chile. Complete dermatological and periodontal evaluations (involving the collection of GCF samples) were made. The levels of 35 proteases were analyzed using a human protease antibody array. The GCF levels of zinc-binding ADAM8, ADAM9, MMP8 and Neprilysin/CD10, aspartyl-binding Cathepsin E, and serin-binding Protein convertase9 and uPA/Urokinase proteases were lower in moderate/severe AD patients compared to controls (p<0.05). No inter-group differences in the levels of the other 28 proteases were found. MMP8, Cathepsin E and ADAM9 were the biomarkers with the highest sensitivity and specificity regarding the detection of AD (p < 0.05). The area under receiver operating characteristic (ROC) curve for MMP-8+ADAMP-9 was 0.90. In conclusion, differences in the protease profile between AD and control patients associated with MMP8, Cathepsin E and ADAM9. MMP8, ADAM9 and Cathepsin E may be useful as combined diagnostic and therapeutic biomarkers of moderate/severe AD.
ARTICLE | doi:10.20944/preprints202003.0093.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: net photosynthetic rate; key enzymes activity; starch pasting viscosity; yield
Online: 5 March 2020 (12:20:24 CET)
Rice-Tartary buckwheat is a special type of Tartary buckwheat with easy hulling thin shell. The local rice-Tartary buckwheat ‘cv. Xiaomiqiao’ (XMQ) was used to explore the characteristics of photosynthesis, starch synthesis, yield and quality, as compared to Tartary buckwheat ‘cv. Jinqiao 2’(JQ2). XMQ showed significantly lower values of net photosynthetic rate, ADPGase activity and starch synthase activity at one or more periods during grain filling, as compared to that of JQ2. The effective branch number and grain number per plant of XMQ were similar to that of JQ2 regardless of different years, but the 1000-grain weight was significantly lighter that resulted in the significantly lower yield. XMQ accumulated similar contents of starch (amylose, amylopectin) and protein (glutelin, albumin, prolamin, globulin) to that of JQ2, but exhibited significantly lower flavonoid content. The values of peak viscosity and hot paste viscosity in XMQ were similar to that of JQ2, but the values of cool paste viscosity, breakdown and setback were significantly lower. In conclusion, XMQ showed low yield due to the insufficient of photosynthesis and starch synthesis. XMQ exhibited high nutritional quality as well as normal Tartary buckwheat and stored 18.88mg g-1 of flavonoid, that can be consumed as daily diet. The present results will provide a basis for food processing and breeding of rice-Tartary buckwheat.
ARTICLE | doi:10.20944/preprints201910.0193.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: antioxidant enzymes; lipid peroxidation; NaCl; Pistacia vera; rootstock; salinity stress
Online: 17 October 2019 (11:53:12 CEST)
Salinity substantially affects plant growth and crop productivity worldwide. Plants adopt several biochemical mechanisms including regulation of antioxidant biosynthesis to protect themselves against the toxic effects induced by the stress. One-year-old Pistachio rootstock exhibiting different degrees of salinity tolerance were subjected to sodium chloride induced salt stress to identify genetic diversity among cultivated pistachio rootstock for their antioxidant responses, and to determine the correlation of these enzymes to salinity stress. Leaves and roots were harvested following NaCl-induced stress. Results show that a higher concentration of NaCl treatment induced oxidative stress in the leaf tissue and to a lesser extent in the roots. Both tissues showed an increase in ascorbate peroxidase, superoxide dismutase, catalase, glutathione reductase, peroxidase and malondialdehyde. Responses of antioxidant enzymes were cultivar dependent, as well as temporal and dependent on the salinity level. Linear and quadratic regression model analysis revealed significant correlation of enzyme activities to salinity treatment in both tissues. The variation in salinity tolerance reflected their capabilities in orchestrating antioxidant enzymes at the roots and harmonized across the cell membranes of the leaves. The study provides a better understanding of root and leaf coordination in regulating the antioxidant enzymes to NaCl induced oxidative stress.
ARTICLE | doi:10.20944/preprints201703.0131.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Rhododendron chrysanthum Pall.; cold stress; chlorophyll fluorescence; photosynthesis; antioxidant enzymes
Online: 17 March 2017 (04:46:21 CET)
Rhododendron chrysanthum Pall., live in Changbai Mountain being exposed to chilling temperature, high light intensities and water scarcity condition. To adapt to the harsh environment, the cold resistance mechanisms of R. chrysanthum have been successfully evolved in the long-term adaptive process. In our present work, the methods of proteomics combined with physiological and biochemical analyses were used to investigate the effects of cold stress on the photosynthesis and antioxidant system of Rhododendron chrysanthum Pall. and the molecular mechanisms involved in cold resistance of plants. A total of 153 photosynthesis related proteins were identified in present work, of which 7 proteins including Rubisco large subunit (rbcL) were up-regulated in experiment group (EG) compared with control group (CG). Simultaneously, four chlorophyll fluorescence parameters were measured in present study. The results showed that the maximum photochemical efficiency of photosystem II (Fv/Fm), actual quantum yield of PSII (Y(II)) and photochemical quenching (qP) were significantly higher in EG, whereas the non-photochemical quenching (NPQ) was notably decreased. Cold stress could lead to a significant reduction in electron transport rate (ETR) accompanied with an increase in excitation pressure (1-qP). The abundance of PetE which involved in the plants photosynthetic electron transfer was also significantly influenced by cold stress. Moreover, the up-regulated expressions and higher levels of enzymatic activities of Glutathione peroxidase (GPX) and Ascorbate peroxidases (APXs) were detected in EG. All these changes which can help plants to survive in low temperature are considered as the crucial parts of cold tolerance mechanisms. These results revealed that photosynthesis and redox adjustment play significant roles in the defense of cold-induced damage.
ARTICLE | doi:10.20944/preprints202310.1739.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Gerbera jamesonii; ascorbic acid; salt stress; antioxidant enzymes; ROS; floriculture industry
Online: 26 October 2023 (16:44:52 CEST)
Cut flowers of Gerbera jamesonii, renowned globally for their vibrant colors and extended shelf life, play a pivotal role in the flourishing floriculture industry. However, repeated fertigation in nethouses/polyhouses poses a significant challenge leading to production losses. In response to this challenge, we hypothesized that the application of Ascorbic acid (AsA), an antioxidant, in optimal concentrations could alleviate the detrimental effects of salt toxicity and enhance Gerbera production. Our objective was to investigate the impact of exogenous AsA (1.0 mM, 2.0 mM, and 4.0 mM) as a foliar spray, followed by NaCl (200 mM) treatment, across two cultivars of Gerbera: white-flowered (salt sensitive) and yellow flowered (salt tolerant) cultivars. The research employed a comprehensive approach, applying AsA and NaCl treatment to evaluate their effects on chlorophyll, proline, and total soluble protein content, MDA, H2O2, and antioxidant enzyme activities (SOD, CAT, APX, GR, and POD). Following exposure to 2.0 mM AsA, treated plants displayed a notable increase in chlorophyll, Proline, and soluble protein content. Concurrently, MDA and H2O2 levels, indicator of intracellular damage, exhibited a decrement, suggesting AsA's protective role against salt stress. Moreover, enhanced antioxidant Enzyme activities were observed. The application of AsA (2.0 mM) not only induced salt tolerance in Gerbera but also showed potential benefits for its overall growth and development. This study underscores the promising role of AsA in mitigating salt-induced challenges in Gerbera cultivation.
ARTICLE | doi:10.20944/preprints202309.0341.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Antioxidative enzymes; Bacillus sp.; Catalase activity; Exopolysaccharide production; Reactive oxygen species
Online: 5 September 2023 (15:38:43 CEST)
Catalase can decompose hydrogen peroxide in plants under controlled and stressed condi-tions. In a stressed environment, the increase in hydrogen peroxide production makes catalase activity a major defense system for plant growth. The current study was conducted to evaluate the catalase activity of pre-isolated and identified bacterial strains Bacillus aryabhattai (AN30), Bacillus megaterium (AN24), Bacillus megaterium (AN31) and Bacillus megaterium (AN35) and their potential for rice seedlings growth promotion. These strains were characterized for quantita-tive catalase, urease, siderophores, and exopolysaccharides production using LB media. Sub-sequently, the effectiveness of these strains was checked by quantifying the catalase activity in the rhizosphere of rice seedlings. Furthermore, the catalase activity was quantified in the roots and shoots of rice seedlings. Plant growth parameters were also studied in a growth room trial. The strain AN24 showed the maximum catalase activity (1.36 mol cm-1), urease ac-tivity (1.35 mol cm 1), exopolysaccharides (4.20 µg mL-1), and siderophores (2.32%) production in LB media. All tested strains showed significantly higher catalase activity in soil compared to control. Among sole application, strain AN24 showed better results; however, consortium application of strains AN24+AN30+AN35+AN31 showed the maximum increase in catalase ac-tivity in the rhizosphere of rice seedlings. Moreover, consortium application of AN24+AN30+AN31+AN35 resulted in the highest increase in catalase activity, dry biomass of shoots and roots, shoot and root length of rice seedlings. The results showed that a consortium of these Bacillus strains with catalase activity has greater potential to enhance an antioxidant defense system and growth promotion of rice seedlings. However, further experimentation under natural conditions is required before using these strains as potential bioinoculants for improving the rice growth and yield.
ARTICLE | doi:10.20944/preprints202307.0617.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: Fermented beverages; type 2 diabetes; postprandial hyperglycemia; carbohydrate metabolizing enzymes; Rice
Online: 11 July 2023 (03:02:32 CEST)
Background: The therapeutic benefits of fermented foods in the treatment and prevention of Type 2 diabetes mellitus have been reported. Aim: Inhibitory effect of fermented rice beverages on α-amylase, α-glucosidase and pancreatic lipase was evaluated. Method: Two fermented rice beverages-fermented rice alone (FKR) and fermented rice plus roasted peanuts (FKRG) were produced using spontaneous fermentation. Capacity of the beverages to inhibit al-pha-glucosidase, alpha-amylase and pancreatic lipase in vitro was evaluated and compared with standards (positive controls). Results: FKR exerted inhibition of α-glucosidase between 9.23-21.11% and FKRG 1.11-17.36% at the various concentrations respectively, with both samples showing the most significant inhibition (about 20%) at 125 μg/mL. FKRG exhibited greater alpha-amylase inhibition activity than FKR, but for both samples, the most significant (P < 0.05) inhibition occurred at 500 μg/mL. With pancreatic lipase, no significant inhibition was observed for both FKR and FKRG at the tested concentrations compared to Orlistat used as control; how-ever, at 31.25 μg /mL FKRG showed an inhibitory effect of approximately 15%, which was not evident at higher concentrations. Conclusion: Low to moderate inhibition of α-amylase, α-glucosidase and pancreatic lipase by both FKR and FKRG, showed that the fermented rice beverages have potential to modulate hyperglycemia in type 2 diabetes in vitro. This is an indi-cation that fermented rice beverage could prevent postprandial hyperglycemia in vivo.
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: web server; rational design; functionalizing enzymes; enzyme discovery; user-friendly tools
Online: 28 January 2021 (07:51:45 CET)
Enzymes are in high demand for very diverse biotechnological applications. However, natural biocatalysts often need to be engineered for fine-tuning their properties towards the end applications, such as the activity, selectivity, stability to temperature or co-solvents, and solubility. Computational methods are increasingly used in this task, providing predictions that narrow down the space of possible mutations significantly and can enormously reduce the experimental burden. Many computational tools are available as web-based platforms, making them accessible to non-expert users. These platforms are typically user-friendly, contain walk-throughs, and do not require deep expertise and installations. Here we describe some of the most recent outstanding web-tools for enzyme engineering and formulate future perspectives in this field.
ARTICLE | doi:10.20944/preprints202009.0255.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: antioxidant enzymes; hydrogen peroxide; phenylalanine ammonia-lyase; proline; scanning electron microscopy
Online: 11 September 2020 (09:58:41 CEST)
Susceptibility of four blood orange cultivars (‘Moro’, ‘Tarocco’, ‘Sanguinello’ and ‘Sanguine’) to chilling injury (CI) was studied. Antioxidant enzymes, physiological and biochemical changes were measured monthly at 2 and 5 °C plus 2 days at 20 °C for shelf life. At 2 °C, CI symptoms were higher than at 5 °C, and ‘Moro’ and ‘Tarocco’ had significantly higher CI than ‘Sanguinello’ and ‘Sanguine’. ‘Moro’ and ‘Tarocco’ had the highest electrolyte leakage, malondialdehyde, H2O2 and polyphenol oxidase activity and lower phenylalanine ammonia-lyase compared with ‘Sanguinello’ and ‘Sanguine’. The scanning electron microscopy micrographs revealed that ‘Moro’ and ‘Taroco’ showed severe fractures in the flavedo due to CI. ‘Sanguinello’ and ‘Sanguine’ were more tolerant to CI due to an increase of catalase, ascorbate peroxidase and superoxide dismutase, which could prevent the loss of membrane integrity and alleviate CI symptoms. The order of susceptibility of cultivars to CI was ‘Moro’> ‘Tarocco’> ‘Sanguine’> ‘Sanguinello’.
ARTICLE | doi:10.20944/preprints201909.0157.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: schistosomiasis; monophosphoryl lipid A (MPLA); chemotherapy; oxidative stress; antioxidant enzymes; SEA
Online: 16 September 2019 (01:27:58 CEST)
Schistosomiasis, a crippling ailment that afflicts over 220 million people worldwide. Yet or up till now, there is no vaccine for schistosomiasis, and chemotherapy relies heavily on a single drug, the praziquantel. The present study was undertaken to investigate the therapeutic effect of Monophosphoryl Lipid A (MPLA) as an adjuvant in soluble egg antigen (SEA) vaccinated mice against the deleterious pathological impacts induced in hepatic tissues of mice by Schistosoma mansoni infection. In addition, to study the associated parasitological, immunological and biochemical parameters. Parasitological parameters showed that intraperitoneal injection of MPLA into SEA-vaccinated and S. mansoni-infected mice was effective to a significant degree in reducing the worm and egg burden, granuloma count and diameter as well as the total area of infection in their livers versus SEA-untreated but infected ones. In addition, MPLA showed ameliorative action on the elevated liver oxidative stress marker, including malondialdehyde (MDA) and decrease in the level of the antioxidant enzymes, reduced glutathione (GSH) and catalase (CAT) which may have a role in the liver damage and fibrosis due to S. mansoni infection. In conclusion, treatment with MPLA has multi-functions in attenuating the deleterious impacts of S. mansoni infection in mice livers. Its effects are mediated through a reduction of ova count, worm burden, granuloma diameter and amelioration of antioxidant defense systems, and liver function biomarkers.
ARTICLE | doi:10.20944/preprints202312.0485.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Plant polysaccharides; Boric acid; finishing pigs; Digestive enzymes; Immune; Antioxidant; Harmful gases
Online: 7 December 2023 (16:44:22 CET)
To investigate the effects of plant polysaccharides combined with boric acid on digestive function, immune function, and harmful gas and heavy metal contents in faeces of finishing pigs, for this study, 90 healthy three-way cross-bred pigs were selected and randomly divided into five groups: Con) A control, fed basic feed; BA) fed basic feed supplemented with 40 mg/kg of boric acid; BA+APS) fed basic feed supplemented with 40 mg/kg of boric acid and 400 mg/kg of Astragalus polysaccharides; BA+GLP) fed basic feed supplemented with 40 mg/kg of boric acid with 200 mg/kg of Ganoderma lucidum polysaccharides; and BA+EPS) fed basic feed supplemented with 40 mg/kg of boric acid and 500 mg/kg of Echinacea polysaccharides. Compared with the Con, the average daily gain (ADG) and trypsin activity were higher in BA, along with there being increased glutathione peroxidase (p < 0.05); furthermore, lower malondialdehyde content and harmful substance emissions from manure were observed (p < 0.05). Compared with BA, increases in ADG, gain-to-feed ratio (G/F), trypsin, and maltase activities were observed in BA+EPS (p < 0.05), as well as a lower NH3 emissions (p < 0.05). Compared with BA, BA+APS exhibited higher ADG, average daily feed intake (ADFI), G/F, trypsin, and maltase activities (p < 0.05), while H2S emissions were lower (p < 0.05). And Taken together, our findings reveal that supplementation with boric acid and plant polysaccharides in the diet of finishing pigs synergistically improved their growth performance, trypsin and maltase activities, and immune function, while also discovered the intestinal digestive enzymes, serum inflammatory factors, oxidative stress responseand emissions of harmful gases and heavy metals from feces and urine were tightly related, further reducing the impact of fecal pollution generated by modern animal husbandry on the environment.
REVIEW | doi:10.20944/preprints202309.0856.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Penicillin-binding protein 2a (PBP2a); Mur enzymes; heterocycles; High-throughput screenings; transpeptidation
Online: 13 September 2023 (09:01:12 CEST)
Staphylococcus aureus is a common pathogen in human. Methicillin resistant Staphylococcus aureus (MRSA) infection poses a big and perplexing difficulty in terms of therapy. The acquisition of the non-native gene PBP2a, which has a decreased tolerance for β-lactam antibiotics, frequently confers resistance. PBP2a has a less attraction for methicillin and it helps bacteria to continue peptidoglycan biosynthesis, and it is cell wall’s core component in bacteria. So, even in the presence of methicillin or any other antibiotic, bacteria develop resistance. Due to resistance-causing genes, S. aureus becomes MRSA. The main premise of the resistance mechanism is well understood. The current demand for novel antibiotics is legitimate in the face of therapeutic concerns posed by resistant micro-organisms. The emphasis of this review is on PBP2a scaffolds and the different screening approaches used to find PBP2a inhibitors. Penicillin, Cephalosporins, Pyrazole-Benzimidazole based derivatives, Oxadiazole containing derivatives, non-β-lactam allosteric inhibitors, 4-(3H)-Quinazolinones, Pyrrolylated chalcone, Bis-2-Oxoazetidinyl macrocycle (β-lactam antibiotics with 1, 3-Bridges), Macrocycle-embedded β-lactams as novel inhibitors, Pyridine-Coupled Pyrimidinones, novel Naphthalimide corbelled aminothiazoximes, non-covalent inhibitors, Investigational-β-lactam antibiotics Carbapenem, novel Benzoxazole derivatives, Pyrazolylpyridine analogues, and other miscellaneous classes of scaffolds for PBP2a are also represented as well as with their biological activity is discussed. The penicillin-binding protein is also discussed, which is the crucial target for the cell wall of MRSA. Various aspects of PBP2a, the cell wall of bacteria, peptidoglycans, different crystal structures of PBP2a, synthetic routes for PBP2a inhibitors, and future perspectives of MRSA inhibitors are also enumerated.
ARTICLE | doi:10.20944/preprints202307.0732.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: Alzheimer’s disease; diltiazem; intra-cerebroventricular; streptozotocin; cognition; amyloid beta; anti-oxidant enzymes
Online: 11 July 2023 (12:29:33 CEST)
Alzheimer’s disease (AD) is an age-related neuropsychiatric disorder and a common cause of progressive dementia. Diltiazem (DTZ), the non-dihydropyridine benzothiazepine class of calcium channel blocker (CCB), used clinically in angina and other cardiovascular disorders have proven neurological benefits. In the present study, the neuroprotective anti-dementia effects of DTZ against intra-cerebroventricular-streptozotocin (ICV-STZ)-induced sporadic AD (SAD)-type rat model was investigated. ICV-STZ-induced cognitive impairments were measured by passive avoidance and Morris water maze tasks. Anti-oxidative enzyme status, pro-inflammatory markers, and amyloid-beta (Aβ) protein expression in rat brain tissues were measured by ELISA kits, Western blotting, and immunostaining techniques. Data revealed that ICV-STZ injection in rats significantly induced cognitive deficits and altered the levels of oxidative and pro-inflammatory markers (p < 0.05 ~ p < 0.001). Treatment with DTZ (10 mg/kg, 20 mg/kg, and 40 mg/kg. p.o.) daily for twenty-one days, 1 h before a single ICV-STZ (3 mg/kg) injection, significantly improved cognitive impairments, ameliorated the ICV-STZ-induced altered nitrite, pro-inflammatory cytokines (TNF-α, and IL-1β) and anti-oxidative enzyme levels (superoxide dismutase, lipid peroxidation, and glutathione). Further, DTZ restored the increased Aβ protein expression in ICV-STZ-induced brain tissue Considering the data obtained, DTZ exhibited a potential neuroprotective anti-dementia role in ICV-STZ-induced SAD-type conditions in rats and might be repurposed as a potential therapeutic agent in the treatment and management of AD and related dementia pathologies.
REVIEW | doi:10.20944/preprints202305.1092.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: weaning; large litters; pain relief; split-suckling; enzymes; L-glutamine; creep feed
Online: 16 May 2023 (05:07:31 CEST)
Weaning is a critical period in the pig’s life. Piglets are confronted with abrupt changes to their physical and social environment, as well as management and nutritional changes. Weaning was always associated with a growth check and was frequently accompanied by post-weaning diarrhea in piglets. However, rapid increases in litter size, in the last decade, has increased within-litter piglet weight variation, with piglets now generally lighter at weaning, making the challenges associated with weaning even greater. Many interventions can be employed during the suckling period to ease the weaning transition for piglets. Pre-weaning strategies such as supervised farrowing (assistance with suckling, oxytocin provision), provision of pain relief to sows around farrowing, split-suckling, early oral supplementation with glucose, bovine colostrum, fecal microbiota transplantation, feed additives, solid and liquid creep feeding (milk and liquid feed) have all been investigated. The objective of these strategies is to stimulate earlier maturation of the digestive tract, improve immunity, reduce latency to the first feed post-weaning and increase early post-weaning feed intake and growth. This review focuses in particular on: 1) pain relief provision to sows around farrowing, 2) split-suckling of piglets, 3) pre-weaning provision of supplementary milk and/or liquid feed, 4) other strategies to stimulate earlier enzyme production (e.g. enzyme supplementation) and 5) other nutritional strategies to promote improved gut structure and function (e.g. L-glutamine supplementation). Correctly implementing these strategies can not only increase post-weaning growth and reduce mortality but also maximize lifetime growth in pigs.
REVIEW | doi:10.20944/preprints202211.0567.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Keywords: Integrated biorefinery; Circular economy; Lignocellulosic biomass; Pretreatment; Valorization; Enzymes; Biofuels; Biochemicals
Online: 30 November 2022 (08:50:21 CET)
An upsurge in global population over the years and rapid urbanization have accelerated huge dependence on petroleum-derived fuels and consequent environment concerns owing to green-house gas emissions in the atmosphere. An integrated biorefinery uses lignocellulosic feedstock as raw material for the production of renewable biofuels, and other fine chemicals. The sustain-able bio-economy and the biorefinery industry would benefit greatly from the effective use of lignocellulosic biomass obtained from agricultural feedstocks to replace petrochemical products. Lignin, cellulose, hemicellulose, and other extractives, which are essential components of ligno-cellulosic biomass, must be separated or upgraded into useful forms in order to fully realize the potential of biorefinery. The development of low-cost and green pretreatment technologies with effective biomass deconstruction potential is imperative for an efficient bioprocess. The abun-dance of microorganisms along with their continuous production of various degradative en-zymes makes them suited for the environmentally friendly bioconversion of agro-industrial wastes into viable bioproducts. The present review highlights the concept of biorefinery, ligno-cellulosic biomass and its valorization by green pretreatment strategies into biofuels and other biochemicals. The major barriers and challenges in bioconversion technologies, environmental sustainability of the bioproducts and promising solutions to alleviate those bottlenecks are also summarized.
ARTICLE | doi:10.20944/preprints202009.0473.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: antioxidant enzymes; DNA methylation; epigenetics; plant resistance; root-knot nematodes; ROS; tomato
Online: 20 September 2020 (14:35:29 CEST)
Two wild-type field populations of root-knot nematodes (Mi-Vfield, Mj-TunC2field), and two isolates selected for virulence in laboratory on resistant tomato cultivars (SM2V, SM11C2), were used to induce a resistance reaction in tomato to the soil-borne parasites. Epigenetic and metabolic mechanisms of resistance were detected and compared with those occurring in partially or fully successful infections. The activated epigenetic mechanisms in plant resistance, as opposed to those activated in infected plants, were detected by analysing the methylated status of total DNA, by ELISA methods, and the expression level of key genes involved in the methylation pathway, by qRT-PCR. DNA hypo-methylation and down-regulation of two methyl-transferase genes (CMT2, DRM5), characterized the only true resistant reaction obtained by inoculating the Mi-1.2-carrying resistant tomato cv Rossol with the avirulent field population Mi-Vfield. On the contrary, in the roots into which nematodes were allowed to develop and reproduce, total DNA was generally found to be hyper-methylated and methyl-transferase genes up-loaded. DNA hypo-methylation was considered to be the upstream mechanism that triggers the general gene over-expression observed in plant resistance. Gene silencing induced by nematodes may be obtained through DNA hyper-methylation and methyl-transferase gene activation. Plant resistance is also characterized by an inhibition of the anti-oxidant enzyme system and activation of the defence enzyme chitinase, as opposed to the activation of such a system and inhibition of the defence enzyme glucanase in roots infested by nematodes.
ARTICLE | doi:10.20944/preprints202308.0076.v1
Subject: Computer Science And Mathematics, Mathematical And Computational Biology Keywords: Chiral drugs; Chirality-induced spin selectivity (CISS); Chiral enzymes; L-DOPA; AADC enzyme
Online: 1 August 2023 (10:40:30 CEST)
The theory of electron spin has been proposed for a century, but the study of quantum effects in biological molecules is still in its infancy. Chirality-induced spin selectivity (CISS) is a very modern theory that can explain many biochemical phenomena. In this paper, we propose a new theoretical model based on CISS theory and quantum chemistry theory, which can well explain the theoretical explanation of the chiral selectivity of chiral proteins. Moreover, this theory can predict the spin state of corresponding chiral molecules. Taking L-DOPA and AADC enzyme as examples, this theoretical model solves the theoretical explanation of AADC enzyme's chiral catalysis selectivity problem and successfully predicts the spin state of L-DOPA and D-DOPA's valence electrons.
ARTICLE | doi:10.20944/preprints202306.0699.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: Biological pretreatment; Ligno-hemicellulolytic enzymes; Corn stover; Enzymatic hydrolysis; Pyrenophora phaeocomes S-1
Online: 9 June 2023 (10:28:39 CEST)
Biological pretreatment of lignocellulosic residues has the potential to serve as a sustainable, less energy-intensive alternative to harsh chemical treatments for enhancing cellulose accessibility, despite the requirement of a lengthy incubation period. The study characterized the simultaneous delignification of corn stover by the white-rot fungus Pyrenophora phaeocomes S-1, as well as the co-production of a ligno-hemicellulolytic enzyme cocktail consisting of laccase, xylanase, and mannanase. The maximum yields of all three components of the cocktail were achieved after just 4 days of incubation under solid-state conditions. Following a 40-day fermentation period, we achieved a cellulose recovery of 44.25 ± 1.72%, attributed to the activities of 133.88 U/gds of laccase, 14.93 U/gds of xylanase, and 1.34 U/gds of mannanase co-produced by the fungus in the medium. Subsequently, through the extraction of biologically treated biomass with 0.5N NaOH after 40 days, the cellulose recovery increased to 66.4 ± 1.39%. Enzymatic hydrolysis of the same, employing only 5 FPU/gds of in-house produced cellulases, resulted in the liberation of 397.84 mg/gds of total reducing sugars after 144h. The findings of this study encourage further optimization of biological pretreatment of lignocellulosic residues and enzymatic hydrolysis to enhance the yields of total reducing sugars for their valorization.
ARTICLE | doi:10.20944/preprints202304.0800.v1
Subject: Biology And Life Sciences, Toxicology Keywords: Brushtail possum; Trichosurus vulpecula; fertility control; and drug-metabolising enzymes (CYP3A and UGT2B)
Online: 23 April 2023 (13:11:28 CEST)
The potential to improve the effectiveness and efficiency of potential estrogen-based oral contraceptives (fertility control) for possums was investigated by comparing the inhibitory potential of hepatic CYP3A and UGT2B catalytic activity using a selected compound library (CYP450 inhibitor-based compounds) in possums to that of three other species (mouse, avian, and human). The results showed higher CYP3A protein levels in possum liver microsomes compared to other test species (up to a 4-fold difference). Also, possum liver microsomes had significantly higher basal p-nitrophenol glucuronidation activity than other test species (up to an 8-fold difference). However, no CYP450 inhibitor-based compounds significantly decreased the catalytic activity of possum CYP3A and UGT2B below the estimated IC50 and 2-fold IC50 values and were therefore not considered to be potent inhibitors of these enzymes. However, compounds such as isosilybin (65%), ketoconazole (72%) and fluconazole (74%) showed reduced UGT2B glucuronidation activity in possums, mainly at 2-fold IC50 values compared to control (p<0.05). Given the structural features of these compounds, these results could provide opportunities for future compound screening. More importantly, however, this study provided preliminary evidence that the basal activity and protein content of two major drug metabolising enzymes differ in possums compared to other test species, suggesting that this could be further exploited to reach the ultimate goal, a potential target-specific fertility control for possums in New Zealand.
ARTICLE | doi:10.20944/preprints202211.0132.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Enterococcus faecalis; natural products; aminoglycosides; aminoglycoside-modifying enzymes; APH(3’)-IIIa; flavone derivative
Online: 8 November 2022 (01:39:19 CET)
Enterococcus faecalis is a bacterium that can develop a multidrug resistance profile associated with the community as well as nosocomial-acquired infections. Among the treatment options for these infections are aminoglycosides combined with bacterial cell wall inhibitors such as beta-lactams, since E. faecalis is intrinsically resistant to aminoglycosides. One of its most representative resistance mechanisms is the expression of aminoglycoside-modifying enzymes, such as the aminoglycoside phosphotransferase type IIIa of E. faecalis (EfAPH(3')-IIIa). This enzyme acts by phosphorylating aminoglycosides in an ATP-dependent reaction, modifying the 3' position of hydroxyl groups of these antibiotics. Considering this scenario, 3,092 natural products obtained from the ZINC22 database were analyzed to select molecules with the highest affinity for the nucleotide-binding pocket of EfAPH(3')-IIIa, which could be potential aminoglycoside adjuvants. The molecules that showed the best-score results obtained from ensemble docking-based virtual screening were ZINC000000952700 (BS-1), ZINC000014793040 (BS-2) and ZINC000015498603 (BS-3). The most promising results were for BS-2, a flavone derivative, due to its improved stability profile in molecular dynamics simulation (average values of RMSD of 0.23 nm, and Rg of 1.94 nm), binding free energy calculations (average ΔG total of -35.3 nm), as well as better toxicological profile (lower probability of hepatotoxicity, carcinogenic, immunotoxicity, mutagenicity, and cytotoxicity effects), compared to BS-1 and BS-3. These results allow us to propose that a flavone derivative may act as an adjuvant to aminoglycosides in the treatment of E. faecalis infections, acting as an inhibitor in the nucleotide-binding pocket of EfAPH(3')-IIIa.
ARTICLE | doi:10.20944/preprints202111.0211.v1
Subject: Biology And Life Sciences, Horticulture Keywords: UV-B radiation; Mango; Fruit maturity; Fruit quality,Photosynthesis; Photosynthetic enzymes; Gene expression
Online: 11 November 2021 (13:01:28 CET)
(1) Background: Investigating the characteristics of photosynthetic physiological changes of leaves in Mangifera indica L. cv. 'GuIfei' under enhanced UV-B radiation, natural light exposed trees were regarded as control, and 96 kJ·m-2·d-1enhanced UV-B radiation was artificially simulated in the field; (2) Methods: The changes of fruit maturity and fruit quality, leaf net photosynthetic rate (Pn), photosynthetic pigments contents, photochemical reaction, activities of photosynthetic enzymes and their genes expressions were determined; (3) Results: Compared with CK, the percentage of mature fruits of the treatment was significantly increased, and fruit quality was better. The net photosynthetic rate (Pn), the contents of photosynthetic pigment, Hill reaction activity and photochemical quenching coefficient (qP) of the treatment leaves showed a significantly higher trend than CK. The activities of Rubisco and RCA, and the expression of Rubisco genes rbcL and rbcS were significantly increased; (4) Conclusions: 96 kJ·m-2·d-1 enhanced UV-B radiation treatment improved Rubisco activity through increasing the expression of Rubisco genes rbcL and rbcS, thereby enhancing the CO2-fixing capacity and dark reaction capacity of leaves. Based on this, it raised the net photosynthetic rate of leaves, which promoted the early maturity of 'Guifei' mango by the fast accumulating photosynthetic products.
REVIEW | doi:10.20944/preprints201906.0042.v2
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: glucosinolate; sulphopharane; allyl isothiocyanate; phase II detoxification enzymes; anti-tumour agents; anti-bacterials.
Online: 27 July 2019 (08:40:12 CEST)
Abstract: This study reviewed aspects of the biology of two members of the glucosinolate family, namely sinigrin and glucoraphanin and their anti-tumour and anti-microbial properties. Sinigrin and glucoraphanin are converted by the β-sulphoglucosidase myrosinase or the gut microbiota into their bioactive forms, allyl isothiocyanate (AITC) and sulphoraphanin (SFN) which constitute part of a sophisticated defence system plants developed over several hundred million years of evolution to protect them from parasitic attack from aphids, ticks, bacteria or nematodes. Delivery of these components from consumption of cruciferous vegetables rich in the glucosinolates also delivers many other members of the glucosinolate family so the dietary AITCs and SFN do not act in isolation. In-vitro experiments with purified AITC and SFN have demonstrated their therapeutic utility as antimicrobials against a range of clinically important bacteria and fungi. AITC and SFN are as potent as Vancomycin in the treatment of bacteria listed by the World Health Organisation as antibiotic-resistant "priority pathogens" and also act as anti- cancer agents through the induction of phase II antioxidant enzymes which inactivate potential carcinogens. Glucosinolates may be useful in the treatment of biofilms formed on medical implants and catheters by problematic pathogenic bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus and are potent antimicrobials against a range of clinically important bacteria and fungi. The glucosinolates have also been applied in the prevention of bacterial and fungal spoilage of food products in advanced atmospheric packaging technology which improves the shelf-life of these products.
ARTICLE | doi:10.20944/preprints201906.0290.v1
Subject: Biology And Life Sciences, Biophysics Keywords: molecular hydrogen; hydrogen-rich water; xenobiotic-metabolizing enzymes; membrane transporters; liver; oxidative stress
Online: 28 June 2019 (07:36:20 CEST)
Molecular hydrogen (H2) has been shown to have antioxidant and anti-inflammatory activities that may reduce the development and progression of many diseases. In this study, Hydrogen-rich water (HRW) was obtained by reacting hybrid magnesium-carbon hydrogen storage materials with water. Then the effects of intake of HRW on the activities of xenobiotic-metabolizing enzymes, membrane transporters, and oxidative stress in rats were investigated. Rats were given HRW ad libitum for 4 weeks. Results showed that intake of HRW had no significant effect on the activities of various cytochrome P450 (CYP) enzymes (CYP1A1, 1A2, 2B, 2C, 2D, 2E1, 3A, 4A), glutathione-S-transferase and UDP-glucuronosyltransferase. Except for a slight lower plasma glucose concentration, intake of HRW had no effect on other plasma biochemical parameters in rats. P-Glycoprotein and multidrug resistance-associated protein (Mrp)2 protein expressions in liver were elevated after intake of HRW. However, HRW had no significant effects on glutathione, glutathione peroxidase, or lipid peroxidation in liver. Results from this study suggest that consumption of HRW may not affect xenobiotic metabolism or oxidative stress in liver. However, intake of HRW may increase the efflux of xenobiotics or toxic substances from the liver into bile by enhancing the expression of p-glycoprotein and Mrp2 protein.
ARTICLE | doi:10.20944/preprints202311.0018.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: protein tyrosine phosphatases; polymerase and histidinol phosphatases; Cap8C; Wzb; metal ion activation; thermophilic enzymes
Online: 1 November 2023 (09:49:36 CET)
Protein tyrosine phosphatases (PTPs) of the polymerase and histidinol phosphatases (PHP) superfamily with characteristic phosphatase activity dependent on divalent metal ions are found in many gram-positive bacteria. Although members of this family are co-purified with metal ions, they still require the exogenous supply of metal ions for full activation. However, the specific roles these metal ions play during catalysis are yet to be well understood. Here, we report the metal ion requirement for phosphatase activities of S. aureus Cap8C and L. rhamnosus Wzb. AlphaFold-predicted structures of the two PTPs suggest that they are members of the PHP family. Like other PHP phosphatases, the two enzymes have catalytic preference for Mn2+, Co2+, and Ni2+ ions. Cap8C and Wzb show an unusual thermophilic property with optimum activities over 75oC. Pre-incubation experiments show that the two enzymes are not inherently thermostable suggesting that certain catalytic step(s) in the reaction mechanism has a high activation energy. Consistent with this model, the activity-temperature profiles of the two enzymes are dependent on the divalent metal ion activating the enzyme.
REVIEW | doi:10.20944/preprints202306.1372.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: Cryptococcus; biofilm; metabolic enzymes; virulence factors; transcription factors; membrane permeases; membrane transporters; catabolite repression
Online: 19 June 2023 (14:43:36 CEST)
Cryptococcus neoformans is a pathogenic fungus that causes cryptococcosis, a significant secondary infection in immunocompromised individuals with immune-suppressive related symptoms from HIV infection and organ transplants. Fungaemia occurs via the respiratory route and spreads by tissue invasion into other body parts. Enzymes and membrane-associated permeases/transporters are accessory proteins deployed to enhance the survival, adaptation, and infection caused by Cryptococcus species. The nutrient bioavailability determines the functional turnover rate of these proteins in the immediate fungal environment. Low oxygen levels in the internal organs, essential micro-elements locked in the storage proteins, catabolite repression, phagolysosomal low glucose level and pH, tight junction, and extracellular matrixes are challenges to the survival of this pathogen in the host. This review identifies key hydrolytic and metabolic enzymes and permeases/transporters as essential weapons of virulence in addition to survival, tolerance, resistance, adaptation, and infection in humans. Under the regulation of different transcription factors, these proteins are released in response to nutrient sensors designed to siphon the host nutrients and induce infection in predisposed individuals. The extracellular secretory vesicles called “exosomal virulence bag” also harbour cryptococcal urease, laccase, phosphatase, and capsular components as additional secretory protein weapons for immune evasion, tissue invasion and persistence.
ARTICLE | doi:10.20944/preprints202305.0222.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Amino acid derivatives; Digestive enzymes; Pancreatic lipase; Pancreatic α-Amylase; α-Glucosidase; Metabolic disorders
Online: 4 May 2023 (07:59:29 CEST)
Over the last decades, the increased incidence of metabolic disorders such as type 2 diabetes and obesity has motivated researchers to investigate new enzyme inhibitors. In this study, the inhibitory effects of synthetic amino acid derivatives (PPC80, PPC82, PPC84, PPC89, and PPC101) on the activity of digestive enzymes was assessed by in vitro assays. The inhibitory effect was determined by the inhibition percentage and the 50% inhibitory concentration (IC50), and the mechanism of action was investigated by Lineweaver–Burk plots. PPC80, PPC82, and PPC84 inhibited pancreatic lipase (IC50 of 1.67–10.23 x 10-1 mmol/L). The activity of pancreatic α-amylase was suppressed by PPC80, PPC82, PPC84, PPC89, and PPC101 (IC50 of 1.62–5.19 x 10-1 mmol/L). Finally, PPC84, PPC89, and PPC101 also showed a potent inhibitory effect on α-glucosidase (IC50 of 0.51–3.53 x 10-1 mmol/L). PPC80 and PPC82 followed a non-competitive inhibition mechanism against pancreatic lipase, while PPC84 acted through competitive inhibition. The inhibition of pancreatic α-amylase by the derivatives was non-competitive, as well as for PPC84, PPC89 and PPC101 against α-glucosidase. The results suggest that these synthetic amino acid derivatives have inhibitory potential against digestive enzymes and may be used as therapeutic agents to control metabolic disorders.
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: biocatalysis; whole cells; cascade reactions; redox enzymes; monooxygenases; Baeyer-Villiger alcohol dehydrogenases; ene-reductases.
Online: 21 April 2021 (10:54:40 CEST)
Baeyer-Villiger monoxygenases (BVMOs) are flavin-dependant oxidative enzymes capable to catalyse the insertion of an oxygen atom between a carbonylic Csp2 and the Csp3 at the alpha position, therefore transforming linear and cyclic ketones into esters and lactones. These enzymes are dependent on nicotinamides (NAD(P)H) for the flavin reduction and subsequent reaction with molecular oxygen to furnish peroxyflavin, the ultimate responsible for the substrate oxidation. BVMOs can be included in cascade reactions, coupled to other redox enzymes such as alcohol dehydrogenases (ADHs) or ene-reductases (EREDs), so that the direct conversion of alcohols or α,β-unsaturated carbonylic compounds to the corresponding esters can be achieved. This way, it is possible to develop smart synthetic strategies with a convenient cofactor recycling, both using whole cells (native or genetically engineered) as well as isolated enzymes, via multi-steps reaction through sequential or parallel methodologies. Some examples will be commented dealing with these biotransformations, highlighting the advantages of the coupling of enzymatic steps.
ARTICLE | doi:10.20944/preprints201801.0201.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Indian ocean; livestock; Extended-Spectrum β-Lactamase producing Enterobacteriaceae; risk factors; CTX-M; enzymes
Online: 22 January 2018 (12:02:53 CET)
In South Western Indian ocean (IO), Extended-Spectrum β-Lactamase producing Enterobacteriaceae (ESBL) are a main public health issue. In livestock, ESBL burden was unknown. The aim of this study was estimating the prevalence of ESBL on commercial farms in Reunion, Mayotte and Madagascar and genes involved. Secondly, risk factors of ESBL occurrence in broiler, beef cattle and pig farms were explored. In 2016-2017, commercial farms were sampled using boot swabs and samples stored at 4°C before microbiological analysis for phenotypical ESBL and gene characterization. A semi-directive questionnaire was performed. Prevalences observed in all production types and territories were elevated, except for beef cattle in Reunion which differed significantly. The most common ESBL gene was the CTX-M-1 subtype. Generalized linear models explaining ESBL occurrence varied between livestock production sectors and allowed identifying main protective (e.g., water quality control and detergent use for cleaning) and risk factors (e.g., recent antibiotic use, other farmers visiting the exploitation, pet presence). This study is the first to explore tools for antibiotic resistance management in IO farms. It provides interesting hypothesis to explore about antibiotic use in IO and ESBL transmission between pig, beef cattle and humans in Madagascar.
COMMUNICATION | doi:10.20944/preprints202311.0164.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Saccharomyces cerevisiae; SAM; radical SAM enzymes; EF2 diphthamide modification; Dph1•Dph2; diphtheria toxin; ADP ribosylation
Online: 2 November 2023 (10:55:02 CET)
In eukaryotes, the Dph1•Dph2 dimer is a non-canonical radical SAM enzyme. Using iron-sulfur (FeS) clusters, it cleaves the cosubstrate S-adenosyl-methionine (SAM) to form a 3-amino-3-carboxy-propyl (ACP) radical for synthesis of diphthamide. The latter decorates a histidine residue on elongation factor 2 (EF2) conserved from archaea to yeast and humans and is important for accurate mRNA translation and protein synthesis. Guided by evidence from archaeal orthologues, we searched for a putative SAM binding pocket in Dph1•Dph2 from Saccharomyces cerevisiae. We predict a SAM binding pocket near the FeS cluster domain that is conserved across eukaryotes in Dph1 but not Dph2. Site-directed DPH1 mutagenesis and functional characterization by assays diagnostic for loss of diphthamide reveal the SAM pocket is essential for synthesis of the décor on EF2 in vivo. Further evidence from structural modeling suggests particularly critical residues close to the methionine moiety of SAM. Presumably, they facilitate a geometry specific for SAM cleavage and ACP radical formation that distinguishes Dph1•Dph2 from classical radical SAM enzymes, which generate canonical 5′-deoxyadenosyl (dAdo) radicals.
ARTICLE | doi:10.20944/preprints202310.1365.v1
Subject: Environmental And Earth Sciences, Water Science And Technology Keywords: algal-bacterial granular sludge; hexavalent chromium; extracellular polymeric substances; anti-oxidant enzymes; self-defensive responses
Online: 20 October 2023 (16:16:10 CEST)
Algal-bacterial granular sludge, a new biological technology, has been widely recognized due to its highly effective pollutant treatment and energy efficiency. This study investigated the effects of environmental concentrations of Cr(VI) (0.5-2.5 mg/L) on the performance of algal-bacterial gran-ular sludge and self-defensive responses after 90 days of cultivation. The results showed that Cr(VI) affected chemical oxygen demand (COD), ammonia-N and phosphate removal with different trends being apparent. A linear decline in COD removal was observed, whereas an initial de-creasing and then increasing ammonia-N and phosphate removal took place. Algal-bacterial granular sludge effectively removed Cr(VI) from wastewater through biological adsorption and reduction, showing the potential to treat Cr(VI)-contaminated wastewater. Cr(VI) affected the community abundance of the algal-bacterial granular sludge, in which Chlorophyceae and cya-nobacteria were vulnerable under Cr(VI)-induced stress. To reduce the toxicity of Cr(VI), over-produced EPS-PN and antioxidant enzymes (MDA, SOD and CAT) acted as self-defensive responses to resist oxidative damage. This study showed that algal-bacterial granular sludge can remove 00.5 mg/L of Cr(VI) without performance loss. It is hoped that this study can provide useful information for improved engineering feasibility of algal-bacterial granular sludge.
ARTICLE | doi:10.20944/preprints202303.0539.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Antibiotic resistance; metallo-β-lactamases; metal-dependent enzymes; broad-spectrum inhibitors; inhibition assays; enzyme kinetics
Online: 31 March 2023 (03:35:02 CEST)
Metallo-β-lactamases (MBLs) are a group of Zn(II)-dependent enzymes that pose a major threat to global health. They are linked to an increasing number of multi-drug resistant bacterial pathogens, but no clinically useful inhibitor is yet available. Since β-lactam antibiotics, which are inactivated by MBLs, constitute ~65% of all antibiotics used to treat infections, the search for clinically relevant MBL inhibitors is urgent. Here, derivatives of a 2-amino-1-benzyl-4,5-diphenyl-1H-pyrrole-3-carbonitrile (1a) were synthesised and their inhibitory effects assessed against representatives of each of the three subgroups of MBLs (B1, B2, B3). Several compounds are potent inhibitors of each MBL tested, making them excellent candidates for the development of broad-spectrum drug leads. In particular, compound 5f is highly potent across the MBL subfamilies, with Ki values in the low µM range. Furthermore, this compound also dis-plays synergy in combination with antibiotics such as penicillin G, cefuroxime or meropenem. This molecule thus represents one of the most promising compounds developed yet to combat MBLs.
REVIEW | doi:10.20944/preprints202302.0042.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Cystic fibrosis; Pseudomonas aeruginosa; antibiotic adjunct; anti-biofilm; biofilm-degrading enzymes; matrix exopolysaccharides; alginate oligosaccharide
Online: 2 February 2023 (09:38:31 CET)
In cystic fibrosis (CF), pulmonary infection with Pseudomonas aeruginosa is a cause of increased morbidity and mortality, especially in patients for whom infection becomes chronic and there is reliance on long-term suppressive therapies. Current antimicrobials, though varied mechanistically and by mode of delivery, are inadequate not only due to eradication failure in many cases, but also because they do not halt the progression of lung function decline over time. One of the reasons for this failure is thought to be the biofilm mode of growth of P. aeruginosa, wherein self-secreted exopolysaccharides (EPSs) provide physical protection against antibiotics and an array of niches with resulting metabolic and phenotypic heterogeneity. Targeting the three EPSs secreted by P. aeruginosa (alginate, Psl and Pel) is currently under investigation as a way of disrupting the biofilm extracellular matrix to potentiate the action of antibiotics. In this review, we look at each EPS as a potential therapeutic target for combatting pulmonary infection with P. aeruginosa in CF, with a particular focus on the current evidence for these emerging therapies and barriers to bringing these therapies into clinic.
REVIEW | doi:10.20944/preprints202008.0286.v2
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: elevated CO2; drought; photosynthesis; transpiration rate; stomatal conductance; C4 enzymes; malate; water deficit stress; abscisic acid
Online: 4 July 2022 (08:21:01 CEST)
The changing dynamics in climate is the primary and important determinant of agriculture productivity. The effects of this changing climate on overall productivity in agriculture can be understood when we study the effects of individual components contributing to the changing climate on plants and crops. Elevated CO2 (eCO2) and drought due to high variability in rainfall is one of the important manifestations of the changing climate. There is a considerable amount of literature that addresses climate effects on plant systems from molecules to ecosystems. Of particular interest is the effect of increased CO2 on plants in relation to drought and water stress. As it is known that one of the consistent effects of increased CO2 in the atmosphere is increased photosynthesis, especially in C3 plants, it will be interesting to know the effect of drought in relation to elevated CO2. The potential of elevated CO2 ameliorating the effects of water deficit stress is evident from literature suggesting that these two are agents are brothers in arms protecting the plant from stress rather than partnering in crime, specifically water deficit when in isolation. The possible mechanisms by which this occurs will be discussed in this minireview. Interpreting the effects of short-term and long-term exposure of plants to elevated CO2 in the context of ameliorating the negative impacts of drought will show us the possible ways by which there can be effective adaption to crops in the changing climate scenario.
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: bovine colostrum; bacteria; pathogens; probiotic bacteria; cost-effective processing; heat treatment; pasteurization; contamination control; immunoglobulins; enzymes
Online: 17 September 2021 (11:51:18 CEST)
The main purpose of bovine colostrum, being the milk secreted by a cow after giving birth, is to transfer passive immunity to the calf. The calves have an immature immune system as they lack immunoglobulins (Igs). Subsequently, the supply of good quality bovine colostrum is required. The quality of colostrum is classified by low bacterial counts and adequate Ig concentrations. Bacterial contamination can contain a variety of human pathogens or high counts of spoilage bacteria, which becomes more challenging with emerging use of bovine colostrum as food and food supplements. There is also a growing risk for the spread of zoonotic diseases originating from bovines. For this reason, processing based on heat treatment or other feasible techniques are required. This review provides an overview of literature on the microbial quality of bovine colostrum and processing methods to improve its microbial quality and keep its nutritional values as food. The highlights of this review are: high quality colostrum is a valuable raw material in food products and supplements, the microbial safety of bovine colostrum is increased using appropriate processing-suitable effective heat treatment, which does not destroy the high nutrition value of colostrum, the heat treatment processes are cost-effective compared to other methods, and heat treatment can be performed in both small- and large-scale production.
ARTICLE | doi:10.20944/preprints202109.0013.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: dextransucrases; GH70; lactic acid bacteria; sucrose-active enzymes; carbohydrate binding module; glucansucrase; cellulose binding domain; Leuconostoc
Online: 1 September 2021 (12:12:00 CEST)
The lactic acid bacteria (LAB) have great potential to produce homoexopolysaccharides (HoPS), have been the subject of extensive research efforts, given their health benefits and physicochemical properties. The HoPS functional properties are determined by structural characteristics of varied molecular weights, types of glycosidic linkages, degrees of branching and chemical composition. The dextransucrases (DSases) are responsible of the synthesis of a kind of HoPS (dextran polymers), which are among the first biopolymers produced at industrial scale with applications in medicine and biotechnology. The concept of glycodiversification opens additional applications for DSases. In that sense the design and characterization of new DSases is of prime importance. Previously, we described the isolation and characterization of a novel extracellular dextransucrase (DSR-F) encoding gene. In this study, from DSR-F, we design a novel chimeric dextransucrase DSR-F-∆SP-∆GBD-CBM2a, where DSR-F-∆SP-∆GBD is fused to the carbohydrate-binding module (CBM2a) of the β-1-4 exoglucanase/xylanase Cex (Xyn10A) of Cellulomonas fimi ATCC 484. This dextransucrase variant is active and without alteration in its specificity. The DSR-F-∆SP-∆GBD-CBM2a is purified by cellulose affinity chromatography for the very first time. Our results indicate that new hybrids and chimeric DSases with novel binding capacity to cellulose can be designed to obtain glyco-biocatalysts from renewable lignocellulosic materials.
ARTICLE | doi:10.20944/preprints202008.0077.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: anti-oxidant activity; anti-oxidant enzymes, anti-proliferative activity; maslinic acid; melanoma; Olea europaea; ROS levels
Online: 4 August 2020 (04:57:13 CEST)
Maslinic acid (MA) is a natural triterpene from Olea europaea whose pharmacological functions have been showed. The objective of this study was to examine MA effect on cell viability (by MTT assay), reactive oxygen species (ROS levels, by flow cytometry) and key anti-oxidant enzyme activities (by spectrophotometry) in murine skin melanoma (B16F10) cells compared to healthy cells (A10). MA induced cytotoxic effects in cancer cells (IC50 42 µM) whereas no effect was found in A10 cells treated with MA (up to 210 µM). In order to produce a stress situation in cells, 0.15 mM of H2O2 were added. Under stressful conditions, MA protected both cell lines against oxidative damage, decreasing intracellular ROS, being higher in B16F10 than in A10 cells. The treatment with H2O2 and without MA produced different responses in anti-oxidant enzymes activities depending on cell line. In A10 cells, all enzymes were up-regulated, but in B16F10 cells only superoxide dismutase, glutathione S-transferase and glutathione peroxidase increased their activities. MA restored the enzyme activities to similar levels than control group in both cell lines, highlighting that in A10 cells the highest MA doses induced values lower than control. Overall, these findings demonstrate the great anti-oxidant capacity of MA.
REVIEW | doi:10.20944/preprints201908.0221.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: luminescence bioassays; bacterial cells; enzymes; fluorescent protein; low-intensity factors; hormesis; radiation; bioactive compounds; antioxidant activity
Online: 21 August 2019 (09:02:20 CEST)
Current paper reviews applications of luminescence bioassays for monitoring low-intensity factors, namely, radioactivity of different types (alpha, beta and gamma), and bioactive compounds (humic substances and fullerenols). Luminescence intensity is taken as a physiological parameter of luminous organisms. High rates of luminescence response can provide (1) a proper number of experiments under comparable conditions and, therefore, proper statistical processing, with this being highly important for ‘noisy’ low-dose exposures; (2) non-genetic, i.e. biochemical and physicochemical mechanisms of cellular response, in accordance to “exposome” concept. Bioassays based on luminous marine bacteria, their enzymes, and fluorescence coelenteramide-containing proteins were used to compare results of low-intensity exposures at cellular, biochemical and physicochemical levels, respectively. Results of the cellular exposures were discussed in terms of hormesis concept. Bioluminescence time dependence under low-dose radiation exposures corresponded to hormesis or threshold models; no bioluminescence monotonic dependency on intensity of exposure (dose rate, radioactivity, concentration) was found. Bioluminescence activation and absence of its dependency on intensity of exposure can be accepted as features of cellular adaptive response. Changes of biological luminescence were analyzed and discussed for bioassays of lower organization level – enzymes and florescent protein.
ARTICLE | doi:10.20944/preprints201907.0290.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Irreversible electroporation, microfluidics, microelectrodes, pulsed electric field electroporation, intracellular metabolites, enzymes, quenching, E. coli, S. cerevisiae
Online: 25 July 2019 (11:44:33 CEST)
Exploring the dynamic behavior of cellular metabolism requires a standard laboratory method that guarantees rapid sampling and extraction of the cellular content. We propose a versatile sampling technique applicable to cells with different cell wall and cell membrane properties. The technique is based on irreversible electroporation with simultaneous quenching and extraction by using a microfluidic device. By application of electric pulses in the millisecond range, permanent lethal pores are formed in the cell membrane of Escherichia coli and Saccharomyces cerevisiae, facilitating the release of the cellular contents; here demonstrated by the measurement of glucose-6-phosphate and the activity of the enzyme glucose-6-phosphate dehydrogenase. The successful application of this device was demonstrated by pulsed electric field treatment in a flow-through configuration of the microfluidic chip in combination with sampling, inactivation, and extraction of the intracellular content in a few seconds. Minimum electric field strengths of 10 kV/cm for E. coli and 7.5 kV/cm for yeast S. cerevisiae were required for successful cell lysis. The results are discussed in the context of applications in industrial biotechnology, where metabolomics analyses are important.
BRIEF REPORT | doi:10.20944/preprints202305.0123.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Aedes aegypti; pyrethroid resistance; kdr mutations; detoxification enzymes; 10ème arrondissement of Cotonou; Godomey-Togoudo; Benin West Africa
Online: 3 May 2023 (09:30:25 CEST)
Epidemics of arboviruses in general, and dengue fever, in particular, are an increasing threat in areas where Aedes (Ae.) aegypti is present. The effectiveness of chemical control of Ae. aegypti is threatened by the increasing frequency of insecticide resistance. The aim of this study was to determine the susceptibility status of Ae. aegypti to public health insecticides and assess the underlying mechanisms driving insecticide resistance. Ae. aegypti eggs were collected in two study sites in the vicinity of houses for two weeks using Gravid Aedes Traps (GATs). After rearing mosquitoes to adulthood, female Ae. aegypti were exposed to the diagnostic doses of permethrin, deltamethrin and bendiocarb, using Centers for Disease Control and Prevention (CDC) bottle bioassays. Unexposed, un-engorged female Ae. aegypti were tested individually for mixed-function oxidase (MFO), glutathione-S-transferase (GST) and esterase activity. Finally, allele-specific PCR (AS-PCR) was used to detect kdr mutations (F1534C, S989P and V1016G) in the voltage-gated sodium channel gene in insecticide-exposed Ae. aegypti. Most traps were oviposition positive; 93.2% and 97% of traps contained Ae. aegypti eggs in the 10ème arrondissement of Cotonou and in Godomey-Togoudo, respectively. Insecticide bioassays assays detected resistance to permethrin and deltamethrin in both study sites and complete susceptibility to bendiocarb. By comparison to the insecticide-susceptibility Rockefeller strain, field Ae. aegypti populations had significantly higher levels of GSTs and significantly lower levels of and esterases; there was no significant difference between levels of MFOs. AS-PCR genotyping revealed the presence of the three kdr mutations (F1534C, S989P and V1016G) at high frequencies; 80.9% (228/282) of Ae. aegypti tested had at least one mutation, while the simultaneous presence of all three kdr mutations was identified in 13 resistant individuals. Study findings demonstrated phenotypic pyrethroid resistance, the overexpression of key detoxification enzymes and the presence of several kdr mutations in Ae. aegypti populations, emphasizing the urgent need to implement vector control strategies, targeting arbovirus vector species in Benin.
ARTICLE | doi:10.20944/preprints202212.0013.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: poly(lactic-co-glycolic acid); silica; nanoparticles; enzymes; amino acid depletion; cancer; drug delivery; double emulsion; biocompatible
Online: 1 December 2022 (07:56:18 CET)
Some cancer cells rely heavily on non-essential biomolecules for survival, growth, and proliferation. Enzyme based therapeutics can eliminate these biomolecules, thus specifically targeting neoplastic cells; however, enzyme therapeutics are susceptible to immune clearance, exhibit short half-lives, and require frequent administration. Encapsulation of therapeutic cargo within biocompatible and biodegradable poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) is a strategy for controlled release. Unfortunately, PLGA NPs exhibit burst release of cargo shortly after delivery or upon introduction to aqueous environments where they decompose via hydrolysis. Here we show the generation of hybrid silica-coated PLGA (SiLGA) NPs as viable drug delivery vehicles exhibiting sub-200 nm diameters, a metastable Zeta potential, and high loading efficiency and content. Compared to uncoated PLGA NPs, SiLGA NPs offer greater retention of enzymatic activity and slow the burst release of cargo. Thus, SiLGA encapsulation of therapeutic enzymes, such as asparaginase, could reduce frequency of administration, increase half-life, and improve efficacy for patients with a range of diseases.
ARTICLE | doi:10.20944/preprints201811.0458.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Bacillus; Bioremediation; Enzymes; Fourier transformed infrared spectroscopy (FTIR); Gas chromatography-mass spectrometry (GC-MS); Physicochemicals; Textile wastewater.
Online: 19 November 2018 (11:19:08 CET)
The present study evaluates the bioremediation potential of indigenous bacterial species isolated from dye-contaminated soil samples from small dyeing outlet located in Ilorin. The water pollution index was estimated based on the physicochemical characteristics and heavy metal concentrations of the raw (Day 0) and treated textile wastewater such as pH, biochemical oxygen demand-5, chemical oxygen demand, total suspended solids and total dissolved solid with mean values of 8.85±0.45 mg/L, 1200±21.3 mg/L, 2440±31.3 mg/L, 1660±17.2 mg/L and 2650±28.1 mg/L respectively, similarly, Lead was the most abundant heavy metal detected in the sample while Cadmium concentration was the lowest with the mean values of 3.52±0.00 mg/L and 2.18±0.00 mg/L respectively. The bacterial strain with highest dye decolorization capacity was screened and identified as Bacillus licheniformis ZUL012.The isolate was consequently used for the bioremediation of the wastewater over a period of 10 days. The results showed an incredible reduction in the physiochemical characteristics and heavy metal concentrations of the textile wastewater in the following ranges (8.85-6.55), (1200-300) mg/L, (2440-518) mg/L, (1660-666) mg/L and (2650-920) mg/L with the highest removal efficiency of 75 %, 78 %, 60%, 65%, recorded for biochemical oxygen demand, chemical oxygen demand, total suspended solid, total dissolved solid, respectively while that of heavy metals such as lead, cadmium, chromium and nickel were 80 %, 60 %, 67 %, 72 % reduction, respectively. Laccase and Azoreductase activities tend to decrease as the pH gradually moved towards acidic condition during the bioremediation process. Toxicity of the treated effluent was assessed using Maize and Bean seed germination test. Conclusively, these research findings can serve as a framework for the outlet design of wastewater treatment plant for local textile outlets.
ARTICLE | doi:10.20944/preprints202101.0155.v2
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Aquaponics; Tilapia; Clarias; Bacteroidetes, Proteobacteria, Actinobacteria, extracellular enzymes, Pseudomonas flourescens; Pseudomonas veronii, plant growth promotion, In vitro antagonistic
Online: 8 February 2021 (15:46:08 CET)
Background: Aquaponics are food production systems advocated for food security and health. Their sustainability from a nutritional and plant health perspective is, however, a significant challenge. Recirculated aquaculture systems (RAS) form a major part of aquaponic systems, but knowledge about their potential to benefit plant growth and plant health is limited. The current study tested if the diversity and function of microbial communities in two commercial RAS were specific to the fish species used (Tilapia or Clarias) and sampling site (fish tanks and wastewaters), and whether they confer benefits to plants and have invitro antagonistic potential towards plant pathogens. Results: Microbial diversity and composition was found to be dependent on fish species and sample site. The Tilapia RAS hosted higher bacterial diversity than the Clarias RAS; but the latter hosted higher fungal diversity. Both Tilapia and Clarias RAS hosted bacterial and fungal communities that promoted plant growth, inhibited plant pathogens and encouraged biodegradation. The production of extracellular enzymes, related to nutrient availability and pathogen control, by bacterial strains isolated from the Tilapia and Clarias systems, makes them a promising tool in aquaponics and in their system design. Conclusions: This study explored the microbial potential of the commercial RAS with either Tilapia or Clarias as a tool to benefit the aquaponic system with respect to plant growth promotion and control of plant diseases.
COMMUNICATION | doi:10.20944/preprints202209.0379.v1
Subject: Chemistry And Materials Science, Other Keywords: fullerene; graphene; molybdenum disulfide; carbon nanotubes; catalysts; density functional theory; enzymes; honeybee biomimicry; drones; depollution; doubly-charged negative ions
Online: 26 September 2022 (05:40:20 CEST)
The Sulfur Dioxide (SO2) compound is a primary environmental pollutant worldwide, whereas elemental Sulfur (S) is a global commodity possessing a variety of industrial as well as commercial functions. The chemical relationship between poisonous SO2 and commercially viable elemental S has motivated this investigation using Density Functional Theory calculation of the relative transition state barriers for the 2-step Dehydro-sulfurization oxidation-reduction reaction. Additionally, doubly-charged nanoscale platelet Molybdenum Disulfide (MoS2), Armchair (6,6) Carbon Nanotube, 28-atom Graphene nanoflake (GR-28), and Fullerene C-60 are utilized as catalysts. The optimal heterogeneous and homogeneous catalysis pathways of the 2-step oxidation-reduction from SO2 to elemental S are further inspired by the biomimicry of the honeybee species multi-step bio-catalysis of pollen conversion to organic honey. Potential applications include environmental depollution, the mining of elemental sulfur, and the functionalization of novel technologies such as the recently patented aerial and amphibious Lynchpin TM drones.
COMMUNICATION | doi:10.20944/preprints202207.0008.v1
Subject: Chemistry And Materials Science, Chemical Engineering Keywords: fullerene, graphene, molybdenum disulfide, carbon nanotubes, catalysts, density functional theory, enzymes, honeybee biomimicry, drones, depollution, doubly-charged negative ions
Online: 1 July 2022 (08:12:59 CEST)
The Sulfur Dioxide (SO2) compound is a primary environmental pollutant worldwide, whereas elemental Sulfur (S) is a global commodity possessing a variety of industrial as well as commercial functions. The chemical relationship between poisonous SO2 and commercially viable elemental S has motivated this investigation using Density Functional Theory calculation of the relative transition state barriers for the 2-step Dehydro-sulfurization oxidation-reduction reaction. Additionally, doubly-charged nanoscale platelet Molybdenum Disulfide (MoS2), Armchair (6,6) Carbon Nanotube, 28-atom Graphene nanoflake (GR-28), and Fullerene C-60 are utilized as catalysts. The optimal heterogeneous and homogeneous catalysis pathways of the 2-step oxidation-reduction from SO2 to elemental S are further inspired by the biomimicry of the honeybee species multi-step bio-catalysis of pollen conversion to organic honey. Potential applications include environmental depollution, the mining of elemental sulfur, and the functionalization of novel technologies such as the recently patented aerial and amphibious Lynchpin TM drones.
ARTICLE | doi:10.20944/preprints202206.0129.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: Diabetic retinopathy; Oxidative stress; Advanced glycation end products (AGEs); Antioxidant enzymes; Vascular endothelial growth factor; B-vitamins; Vitamin-C; Vitamin- E
Online: 8 June 2022 (12:40:07 CEST)
Excessive intracellular glucose in insulin independent tissues including nerve, nephron, lens and retina invites mishandling of metabolism of glucose resulting in a background of increased oxidative stress, advanced glycation end products (AGE) formation, lipid peroxidation and failure of antioxidant defense systems in type 2 diabetes mellitus (T2DM). All these detrimental biochemical anomalies ultimately attack biological membranes and especially capillary beds of retina and glomerulus of kidney, resulting in break-down of inner blood-retinal i.e. initiation of diabetic retinopathy (DR). If these disarrays are corrected to a large extent, development of DR can be avoided or delayed. In this prospective clinical trial, 185 patients with T2DM who received B-vitamins, vitamin-C, and E along with anti-diabetic medication for five years, demonstrated a slower rate of the development of DR and reduced abnormal biochemical mediators like reactive oxygen species (ROS), malondialdehyde (MDA), AGE, and vascular endothelial growth factor (VEGF) compared to 175 T2DM individuals who were treated with only anti-hyperglycemic drugs.
REVIEW | doi:10.20944/preprints202009.0263.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: marine fisheries; aquatic organisms; brachyura; anomura; commercial crab species; red king crab; Kamchatka crab; processing waste; hepatopancreas; waste recycling; enzymes; proteases; hyaluronidase
Online: 12 September 2020 (04:02:24 CEST)
Since the early 1980s, a large number of research works on enzymes from the red king crab hepatopancreas have been conducted. These studies have been relevant both from a fundamental point of view for studying the enzymes of marine organisms and in terms of the rational management of nature to obtain new and valuable products from the processing of crab fishing waste. Most of these works were performed by Russian scientists due to the area and amount of waste of red king crab processing in Russia (or the Soviet Union). However, the close phylogenetic kinship and the similar ecological niches of commercial crab species and the production scale of the catch provide the bases for the successful transfer of experience in the processing of red king crab hepatopancreas to other commercial crab species mined worldwide. This review describes the value of recycled commercial crab species, discusses processing problems, and suggests possible solutions to these problems. The main emphasis is placed on the enzymes of the hepatopancreas as the most highly salubrious product of waste processed from red king crab fishing.
ARTICLE | doi:10.20944/preprints202012.0002.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: 3-ketosteroid Δ1-dehydrogenase; KSTD; KSDH; AcmB; 1,2-dehydrogenation; cholest-4-en-3-one Δ1-dehydrogenase; enzyme immobilization; FAD-dependent enzymes; enzyme immobilization
Online: 1 December 2020 (08:11:00 CET)
Cholest-4-en-3-one Δ1-dehydrogenase (AcmB) from Sterolibacterium denitrificans is successfully immobilized on 3-aminopropyltrimethoysilane functionalized MCF and SBA-15 silica supports using adsorption or covalently with glutaraldehyde or divinyl sulfone linkers. The best catalyst, AcmB on MCF linked covalently with glutaraldehyde, retains the specific activity of the homogenous enzyme while exhibiting a substantial increase of the operational stability. The immobilized enzyme was used continuously in the fed-batch reactor for 27 days, catalyzing 1,2-dehydrogenation of androst-4-en-3-one to androst-1,4-dien-3-one with a final yield of 29.9 mM (8.56 g/L) and 99% conversion. The possibility of reuse of the immobilized catalyst was also demonstrated and resulted with a doubling of the product amount compared to that in the reference homogenous reactor. Finally, it was shown that molecular oxygen from the air can efficiently be used as an electron acceptor either reoxidizing directly the enzyme or the reduced DCPIPH2. Keywords: 3-ketosteroid D1-dehydrogenase; KSTD; KSDH; AcmB; 1,2-dehydrogenation; cholest-4-en-3-one Δ1-dehydrogenase; enzyme immobilization, FAD-dependent enzymes; enzyme immobilization;