Subject: Biology, Other Keywords: Pseudoalteromonas；proteases；hydrolysis；collagen；antioxidant peptides
Online: 24 July 2019 (11:56:00 CEST)
In this study, an extracellular metalloprotease from Pseudoalteromonas sp. H2 was purified and identified. The EH2 maintained more than 80% activity over a wide pH range of 5-10 and the stability was also nearly independent of pH. More than 65% of activity was detected in a wide temperature of 20-70℃. The high stability of the protease in presence of different surfactants and oxidizing agent was also observed. Moreover, we also investigated the antioxidant activities of the hydrolysates generated from porcine and salmon skins collagen by EH2. The results show that salmon skins collagen hydrolysates demonstrated higher DPPH (42.88%±1.85) and hydroxyl radical (61.83%±3.05) scavenging activity compared to those produced with porcine skins collagen. For oxygen radical absorbance capacity, the hydrolysates from porcine skins collagen had higher efficiency (7.72±0.13 μmol·TE/μmol). Even 1 nM mixed peptides can effectively reduce the levels of intracellular ROS. And the two type of substrates exerted the best antioxidant activity when hydrolyzed for 3 hours. Hydrolysis time and type of substrate exerted important effect on the antioxidant property of hydrolysates. This study may have implications for the potential application of marine protease in biocatalysis industry. In addition, the hydrolyzed peptides from meat waste containing beneficial collagen by protease have good antioxidant activity indicating it may be a potential additive in the food processing industry and cosmetics industry.
ARTICLE | doi:10.20944/preprints202203.0201.v2
Subject: Life Sciences, Microbiology Keywords: Entamoeba histolytica; Lactobacillus acidophilus; probiotic; redoxomics; cysteine proteases
Online: 12 April 2022 (10:22:25 CEST)
Amebiasis is an intestinal disease transmitted by the protist parasite, Entamoeba histolytica. Lactobacillus acidophilus is a common inhabitant of healthy human gut and a probiotic that has antimicrobial properties against a number of pathogenic bacteria, fungi, and parasites. The aim of this study was to investigate the amebicide activity of L. acidophilus and its mechanisms. For this purpose E.histolytica and L.acidophilus were co-incubated and the parasite’s viability was determined by eosin dye exclusion. The level of ozidized proteins (OXs) in the parasite was determined by resin-assisted capture RAC (OX-RAC). Incubation with L.acidophilus for two hours reduced the viability of E.histolytica trophozoites by 50%. As a result of the interaction with catalase, an enzyme that degrades hydrogen peroxide (H2O2) to water and oxygen, this amebicide activity is lost, indicating that it is mediated by H2O2 produced by L.acidophilus. Redox proteomics shows that L. acidophilus triggers the oxidation of many essential amebic enzymes like pyruvate:ferredoxin oxidoreductase, the lectin Gal/GalNAc and cysteine proteases (CPs). Further, trophozoites of E.histolytica incubated with L.acidophilus show reduced binding to mammalian cells. These results support L.acidophilus as a prophylactic candidate against amebiasis.
ARTICLE | doi:10.20944/preprints201910.0026.v2
Subject: Life Sciences, Molecular Biology Keywords: ticks; Ixodes scapularis; blood digestion; serine proteases; trypsin
Online: 24 February 2020 (04:45:09 CET)
Ixodes scapularis is the major vector of Lyme disease in the eastern United States. Each active life stage (larva, nymph, and adult) takes a blood meal either for developing and molting to the next stage (larvae and nymphs) or for oviposition (adult females). This protein-rich blood meal is the only food taken by Ixodes ticks and therefore blood digestion is very important for tick survival. Most studies on blood digestion in ticks have shown that the initial stages of digestion are carried out by cathepsin proteases within acidic digestive cells. However, most of these studies have focused on partially engorged ticks. In other hematophagous arthropods, the serine proteases play an important role in blood protein degradation. In this study, we determined transcript expression of four I. scapularis serine proteases with previously characterized roles in blood digestion. RNA interference was used for functional analysis and a trypsin-benzoyl-D, L-arginine 4-nitoanilide assay was used to measure active trypsin levels. An in vitro hemoglobinolytic assay was performed with or without serine protease inhibitor. Our data suggest that trypsin levels increase significantly after blood feeding and peaked in larvae, nymphs, and adults at 3, 1, and 1 day post host detachment, respectively. The knockdown of three previously identified serine proteases by RNAi negatively impacted blood intake, survival, fecundity, levels of active trypsin in the gut and resulted in lower hemoglobin degradation in vitro. A trypsin inhibitor, PMSF, blocked the action of trypsin in the gut extract resulting in 65% lower hemoglobin degradation. We provide evidence of the serine proteases as digestive enzymes in fully engorged, replete females. Our data also demonstrated that in addition to blood digestion, these serine proteases might have a role in blood feeding success in I. scapularis.
ARTICLE | doi:10.20944/preprints202208.0242.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: hydrogel; 3D-culture; Imaging; Cell-matrix; proteases; matrix metalloproteinases; actin polymerization; contractility
Online: 12 August 2022 (12:55:21 CEST)
Cancer invasion through basement membranes represents the initial step of tumor dissemination and metastasis. However, little is known about how human cancer cells breach basement membranes. Here, we used a 3-dimensional in vitro invasion model consisting of cancer spheroids encapsulated by a basement membrane and embedded in 3D collagen gels to visualize the early events of cancer invasion by confocal microscopy and live-cell imaging. Human breast cancer cells generated large numbers of basement membrane perforations, or holes, of varying sizes that expanded over time during cell invasion. We used a wide variety of small molecule inhibitors to probe the mechanisms of basement membrane perforation and hole expansion. Protease inhibitor treatment (BB94), led to a 63% decrease in perforation size. After myosin II inhibition (blebbistatin), basement membrane perforation area decreased by only 15%. These treatments produced correspondingly decreased cellular breaching events. Interestingly, inhibition of actin polymerization dramatically decreased basement membrane perforation by 80% and blocked invasion. Our findings suggest that human cancer cells can primarily use proteolysis and actin polymerization to perforate the BM and to expand perforations for basement membrane breaching, with a relatively small contribution from myosin II contractility.
REVIEW | doi:10.20944/preprints202111.0190.v1
Subject: Keywords: Malaria; proteases; Plasmodium rhomboids; dipeptidyl aminopeptidases; apical membrane antigen; subtilisin-like proteins; glucose transporters; schizogony; plasmepsins
Online: 9 November 2021 (15:50:12 CET)
There is an overarching need to find alternative treatment options for malaria and this quest is more pressing in current times due to the morbidity and mortality data arising from most endemic countries and partially owing to the fact that the SARS-Cov-2 pandemic has diverted much public health attention. Additionally, the therapeutic options available for malaria has been severely threatened with the emergence of resistance to almost all existing drugs by the human malaria parasite. The Artemisinin Combination Therapies (ACTs) which hitherto have been the mainstay for malaria have encountered resistance in South East Asia, a notorious ground zero for the emergence of antimalarial drug resistance. This review analyses few key druggable targets of the parasite and the potential to leverage strategic inhibitors to mitigate the scourge of malaria by providing a concise assessment of the essential proteins of the malaria parasite that could serve as targets. Furthermore, this work provides a summary of the advances made in malaria parasite biology and the potential to leverage such findings for antimalarial drug production.
REVIEW | doi:10.20944/preprints202009.0263.v1
Subject: Life Sciences, 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.
REVIEW | doi:10.20944/preprints202101.0304.v1
Subject: Life Sciences, Biochemistry Keywords: Vascular Endothelial Growth Factors (VEGFs); VEGF-A; PlGF; VEGF-B; VEGF-C; VEGF-D; angiogenesis; lymphangiogenesis; CCBE1; proteases; ADAMTS3; plasmin; cathepsin D; KLK3; prostate-specific antigen (PSA); thrombin; wound healing; metastasis; proteolytic activation; vascular biology
Online: 18 January 2021 (09:05:58 CET)
Specific proteolytic cleavages turn on, modify, or turn off the activity of vascular endothelial growth factors (VEGFs). Proteolysis is most prominent among the lymphangiogenic VEGF-C and VEGF-D, which are synthesized as precursors that need to undergo enzymatic removal of their C- and N-terminal propeptides before they can activate their receptors. The activating cleavage of VEGF-C is mediated by at least five different proteases: plasmin, ADAMTS3, prostate-specific antigen, cathepsin D, and thrombin. All of these proteases except for ADAMTS3 can also activate VEGF-D. Processing by different proteases results in distinct forms of the "mature" growth factors, which differ in affinity and receptor activation potential. The “default” VEGF-C-activating enzyme ADAMTS3 does not activate VEGF-D and therefore, VEGF-C and VEGF-D do function in different contexts. VEGF-C itself is also regulated in different contexts by different proteases. During embryonic development, ADAMTS3 activates VEGF-C. In contrast, thrombin and plasmin likely activate VEGF-C/-D during tissue injury-induced lymphangiogenesis, and PSA and cathepsin D perhaps during tumor-associated pathological lymphangiogenesis. Additionally, cathepsin D from saliva might activate latent VEGF-C/-D upon wound licking, thereby accelerating healing. Similar to tyrosine kinase receptors and VEGFs themselves, these activating proteases could be targeted to modulate angiogenesis and lymphangiogenesis in relevant diseases.