No abstract

Activity was found for chitinase and chitobiase in the crystalline styles of American oysters (Crassostrea virginica Gmelin) collected from the Chesapeake Bay (Maryland, USA). The oysters were maintained in tanks on natural food from a constant flow of unfiltered estuarine water. Chitinase and chitobiase specific activities were compared with total, viable, and chitinoclastic bacterial counts andCristispira counts. Regression analyses revealed that one correlation, chitobiase vsCristispira, was significant (P < 0.05). Several oysters were fed chitin in the presence or absence of chloramphenicol. Although no chitinoclasts were present in the antibiotic-treated oysters, the treatment means did not differ significantly (P > 0.05) for either chitinase or chitobiase activity. In several cases with both chitin-fed and naturally fed oysters, enzyme activity was found when noCristispira were present. The results of the investigations suggest that the oyster produces chitinase and chitobiase endogenously.

No abstract

Computational screening for potentially bioactive molecules using advanced molecular modeling approaches including molecular docking and molecular dynamic simulation is mainstream in certain fields like drug discovery. Significant advances in computationally predicting protein structures from sequence information have also expanded the availability of structures for nonmodel species. Therefore, the objective of the present study was to develop an analysis pipeline to harness the power of these bioinformatics approaches for cross-species extrapolation for evaluating chemical safety. The Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool compares protein-sequence similarity across species for conservation of known chemical targets, providing an initial line of evidence for extrapolation of toxicity knowledge. However, with the development of structural models from tools like the Iterative Threading ASSEmbly Refinement (ITASSER), analyses of protein structural conservation can be included to add further lines of evidence and generate protein models across species. Models generated through such a pipeline could then be used for advanced molecular modeling approaches in the context of species extrapolation. Two case examples illustrating this pipeline from SeqAPASS sequences to I-TASSERgenerated protein structures were created for human liver fatty acid-binding protein (LFABP) and androgen receptor (AR). Ninety-nine LFABP and 268 AR protein models representing diverse species were generated and analyzed for conservation using template modeling (TM)-align. The results from the structural comparisons were in line with the sequence-based SeqAPASS workflow, adding further evidence of LFABL and AR conservation across vertebrate species. The present study lays the foundation for expanding the capabilities of the web-based SeqAPASS tool to include structural comparisons for species extrapolation, facilitating more rapid and efficient toxicological assessments among species with limited or no existing toxicity data.