Environmental concentration of ammonia nitrogen induced marked changes in proteome of clam Ruditapes philippinarum in dose- and time-dependent manner

Previous studies have revealed that ammonia nitrogen has several adverse effects on clam Ruditapes philippinarum . However, knowledge is lacking regarding the related proteins involved in the toxicological responses, which is vital to elucidate the underlying mechanism of ammonia nitrogen. In this study, clams R. philippinarum were exposed to ammonia nitrogen for 21 d at two environmentally relevant concentrations. The tandem mass tags approach (TMT) was applied to assay the differentially expressed proteins (DEPs) in clam gill tissues on the 3 rd and 21 st day. Finally, a total of 7 263 proteins were identified. Bioinformatics analyses revealed that clam protein profiles changed in dose- and time-dependent manner after ammonia nitrogen exposure. We inferred that the clams may face heavy challenges after ammonia exposure, such as unbalanced gender ratio, lysosomal disease, energy lack, neurological disorders, altered glutamine metabolism, increased lipid synthesis, and impaired immunity. Variation profiles of enzyme activities of glutaminase and glutamine synthase provided direct evidence to verify the related inference from proteome data. Most of the inferred toxic effects merit further study. This study identified important proteins related to ammonia nitrogen toxicity in the clam and indicated the severe stress of marine ammonia pollution on the healthy development of mollusc aquaculture.