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Triacylglycerols (TAGs) are a primary energy source for marine mammals during lipid digestion. Walruses (Odobenus rosmarus divergens) consume prey with a high content of long-chain polyunsaturated fatty acids; however, their digestive physiology and lipid digestion remain poorly studied. The present study aims to model and characterize the gastric (PWGL) and pancreatic (PWPL) lipases of Pacific walruses using an in-silico approach. The confident 3D models of PWGL and PWPL were obtained via homology modeling and protein threading and displayed the structural features of lipases. Molecular docking analysis demonstrated substrate selectivity for long-chain TAG (Trieicosapentaenoin; TC20:5n-3) in PWGL and short-chain TAG (Trioctanoin; TC8:0) in PWPL. Molecular dynamics simulations demonstrate that PWGL bound to tridocosahexaenoin (TC22:6n-3), the protein is considerably stable at all three salinity conditions, but fluctuations are observed in the regions associated with catalytic sites and the lid, indicating the potential hydrolysis of the substrate. This is the first study to report on the digestion of TAGs in walruses, including modeling and lipases characterization and proposing a digestive tract for pinnipeds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Crassostrea virginica was exposed to different light crude oil levels to assess the effect on transcriptomic response and metabolic rate. The exposure time was 21 days, and levels of 100 and 200 μg/L were used, including a control. The most significant difference among treatments was the overexpression of several genes associated with energy production, reactive oxygen species (ROS) regulation, immune system response, and inflammatory response. Also, a hydrocarbon concentration-related pattern was identified in ROS regulation, with a gene expression ratio near 1.8:1 between 200 and 100 μg/L treatments. Statistical analysis showed no interaction effect for metabolic rate; however, significant differences were found for oil concentration and time factors, with a higher oxygen consumption at 200 μg/L. Our findings provide novel information about the metabolic response of C. virginica during hydrocarbons exposure. In addition, our results point out which biological processes should be investigated as targets for searching bioindicators., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A new weak hemorrhagic metalloproteinase named BtaMP-1 was purified from Bothriopsis taeniata snake venom by molecular exclusion followed by anion exchange chromatographies. This protein showed a molecular mass of 25,968.16 Da and is composed of 218 amino acid residues. The multiple alignments of its partial amino acid sequence showed high structural identity with other P-I class SVMP. BtaMP-1 showed caseinolytic activity that was enhanced by Ca 2+ ion, completely inhibited by chelating and reducing agents and can be classified as an α-fibrinogenolytic enzyme. Locally, BtaMP-1 induces hemorrhage and edema, but not myotoxicity. These findings were confirmed by histological analysis of mouse gastrocnemius muscle. "In vitro" studies suggest that BtaMP-1 induce cytotoxicity in myoblast C2C12 but not in the myotubes cell line. BtaMP-1 induced systemic alterations in mice with one MHD and two hours exposure; histological analysis of lungs showed hemorrhagic areas, congestion, and increase the thickness of alveolar septum. Also, this protein induced mild effects on kidney and disruption of coagulation by depletion of fibrinogen plasma levels. This work provides insights into the importance of BtaMP-1 biological effects in envenomation by Bothropsis taeniata snake venom and providing further evidence to understand the role of P-I class SVMP in ophidian envenomation., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A 3-year research program was undertaken to assess potential environmental disturbance caused by the Deepwater Horizon oil spill to the soft-bottom macrobenthic communities within Mexican waters of the northwestern Gulf of Mexico. Community properties and temporal/spatial variability were analyzed besides toxicant parameters such as hydrocarbons and trace-metals. Overall infaunal density increased, taxa proportion changed, and small-size opportunistic organisms prevailed throughout the study. Annual abundance-biomass comparison (ABC) curves revealed progressive stress scenarios from moderate to severe. Concentrations of vanadium, nickel, cobalt, PAHs and AHs increased gradually over time. However, low correlations between benthic density and biogeochemical variables were determined. Initially, sedimentary properties were the main drivers of benthic community structure; subsequently, nickel, vanadium and PAHs, indicative of anthropogenic effect, were highlighted. Interannual variability in the macroinfauna was attributed to the synergy of several environmental factors. Undoubtedly, compounds derived from fossil fuels had a significant disturbance role, but their source remains uncertain., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Snake venoms are composed of approximately 90% of proteins with several pharmacological activities having high potential in research as biological tools. One of the most abundant compounds is phospholipases A2 (PLA2), which are the most studied venom protein due to their wide pharmacological activity. Using a combination of chromatographic steps, a new PLA2 K49 was isolated and purified from the whole venom of the Bothriopsis taeniata and submitted to analyses mass spectrometry. An automatic “de novo” sequencing of this new PLA2 K49 denominated Btt-TX was performed using Peaks Studio 6 for analysis of the spectra. Additionally, a triplex approach CID/HCD/ETD has been performed, to generate higher coverage of the sequence of the protein. Structural studies correlating biological activities were made associating specific Btt-TX regions and myotoxic activity. Lysine acetylation was performed to better understand the mechanism of membrane interaction, identifying the extreme importance of the highly hydrophobic amino acids L, P and F for disruption of the membrane. Our myotoxical studies show a possible membrane disruption mechanism by Creatine Kinase release without a noticeable muscle damage, that probably occurred without phospholipid hydrolyses, but with a probable penetration of the hydrophobic amino acids present in the C-terminal region of the protein.

Four proteins with phospholipase A2 (PLA2) activity, designated P9a(Cdt-PLA2), P9b(Cdt-PLA2), P10a(Cdt-PLA2) and P10b(Cdt-PLA2) were purified from the venom of Crotalus durissus terrificus by two chromatographic steps: a gel filtration and reversed phase HPLC. The profile obtained clearly shows that three of them have a similar abundance. The molecular mass, 14193.8340Da for P9a(Cdt-PLA2), 14134.9102Da for P9b(Cdt-PLA2), 14242.6289Da for P10a(Cdt-PLA2) and 14183.8730Da for P10b(Cdt-PLA2), were initially evaluated by SDS-PAGE and confirmed by ESI-Q-TOF spectrometry, and all of them displayed a monomeric conformation. Also, partial amino acid sequence of each protein was obtained and their alignments with other crotalic PLA2 revealed a high degree of identity among them. Additionally, we studied some pharmacological activities like neurotoxicity, myotoxicity and lethality, which prompted us to pick two of them, P9a(Cdt-PLA2) and P10a(Cdt-PLA2) that resulted to be less toxic that the others, and further characterize them to be used as immunogen. We next injected these last proteins in mice to produce antitoxins against them and ELISA and dot blots reveled that both toxins do not show immunogenic differences, unlike those other pharmacologic activities tested. Furthermore, the antibodies produced cross-reacted with all the isoforms purified demonstrating the feasibility of using only one of them and ensuring the cross-reaction of all. The results obtained show that P9a(Cdt-PLA2) isoform has the lowest toxicity and also a good purification performance; thus this protein may be a promising candidate to be employed in the production of crotalic antitoxins., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Phospholipases A(2) (PLA(2)) are important constituents of snake venoms, being responsible for several of their toxic actions. Extracts from plants used in folk medicine were screened for inhibition of the enzymatic activity of myotoxin I, a PLA(2) from Bothrops asper. Piper umbellatum and Piper peltatum extracts tested positive, and their fractionation resulted in the isolation of 4-nerolidylcatechol. Its inhibitory effects towards toxic activities of two Bothrops myotoxins, representing catalytically active (Asp49) and catalytically inactive (Lys49) types of group II PLA(2)s, respectively, were characterized. The enzyme activity of B. asper myotoxin I was completely inhibited by 4-nerolidylcatechol at an inhibitor:toxin ratio of 10:1 (wt/wt) with an IC50 of approximately 1mM. In addition, 4-nerolidylcatechol inhibited representatives of groups I and III of PLA(2)s. Its preincubation with Bothrops myotoxins significantly reduced their myotoxic and edema-inducing activities in animal experiments. However, when 4-nerolidylcatechol was administered in situ, immediately after toxin injection, its inhibitory ability was substantially lower or negligible. This might be explained by the rapid action of these toxins in vivo, together with the slow inactivation of PLA(2) activity observed in vitro. Electrophoretic and chromatographic analyses of myotoxins ruled out major changes in protein charge, hydrophobicity, or gross molecular mass being involved in the inhibition mechanism. Mass spectrometry determinations are consistent with the covalent modification of myotoxin by one molecule of 4-nerolidylcatechol. Finally, a novel compound was isolated from both Piper species, sharing the nerolidyl skeleton, but nevertheless not being inhibitory towards the PLA(2)s studied.

Degenerate oligonucleotide primers were made to peptide sequences from hydroxylamine oxidoreductase (HAO) from Nitrosomonas europaea. The primers were used singly in PCR reactions to amplify portions of the gene for HAO from genomic DNA. Southern hybridizations using fragments amplified with each primer showed that they labeled the same genomic DNA fragments. The PCR-amplified fragments were successfully used to screen a gene library for clones containing the HAO gene. The method of isolating genes by PCR with single primers has general utility.