In this study, proteomics and metabolomics were applied to determine the molecular biomarkers of S. olivacea in response to metal pollution. Furthermore, arsenic will undergo xenobiotic metabolism to form a new arsenic derivative of methylarsonic acid which was demonstrated to induce single -strand DNA breaks that lead to cell damage(Sordo et al., 2001). To date, there is lacking study has reported the interactions of methylarsonic acid with protein receptors, including oxygenated hemocyanin and Scylla paramamosain arginine kinase. Active amino acids and nonbonding interactions with the ligand (monomethylarsonic acid) were determined to validate the Journal Pre-proof Journal Pre-proof ecotoxicological effects of the arsenic and to support the underlying mechanism of monomethylarsonic acid (metabolite of arsenic) exposure in the mud crab. Interestingly, there is no study has reported on the ecotoxicological effects of heavy metals in mud crabs using integrative tools of omics and bioinformatics. Thus, this study will provide insight into new integrative techniques of proteomics, metabolomics, and molecular docking to highlight the ecotoxicological effects of heavy metal in mud crabs, as well as human risk assessment of heavy metal exposure.

The current study showed the average of heavy metal contained in muscle tissues of mud crabs was arranged accordingly; Zn > Cu > As > Cr > Pb > Cd, Ni for Setiu Wetlands while Zn > Cu > Cr > As > Ni > Pb > Cd for Kuala Sepetang.

The up -regulated of Hsp70 in Kuala Sepetang (a metal -polluted site) in this study showed this protein played a vital role in repairing the damage protein damage that was affected by exposure to heavy metals. Another protein that was listed in the identification of the protein band at ~ 70 kDa was hemocyanin protein from tissues of mud crabs from both sampling locations and are involved in major physiological processes such as aerobic respiration, immune response, and molting (Terwilliger et al., 2006). The high level s of Zn and Cu will help hemocyanin to transport oxygen throughout the body of crustaceans (Jakimska et al., 2011). A current study suggested the muscle of mud crabs from the metal -polluted site (Kuala Sepetang) disrupted the energy metabolisms since both myosin tail 1 domain -containing protein and sarcoplasmic calcium -binding protein were down -regulated. Arginine kinase was found to up -regulated expressions with 5.47 fold in muscles of mud crabs collected from metal -polluted sites (Kuala Sepetang), indicates the enzyme was highly expressed in the tissues of mud crabs to produce more ATP to overcome oxidative stress.

As evidenced by downregulated expressions of myosin tail 1 domain -containing protein and sarcoplasmic calcium -binding protein in proteomic analyses, and altered levels of succinate, lactate, and glucose in metabolomics analyses, these findings imply the occurrence of energy production disruptions in mud crabs from the metal - polluted site. The elevated choline levels discovered in the Kuala Sepetang mud crab samples also suggest that there is a problem with the osmotic metabolisms. In addition, our findings suggest that mud crabs' immune systems may be impacted by exposure to heavy metals. The normal functioning of marine creatures' biological systems may be disrupted by the potential blockage caused by energetically favorable interactions and the participation of active amino acids in subunit II of the oxygenated hemocyanin molecule. This interaction involves Scylla paramamosain arginine kinase and monomethylarsonic acid (MMA), which is a toxic derivative. The presence of MMA has the potential to interfere with the regular functioning of the marine creature's biological system. SOD, GSH, and GST activity were examined in mud crabs to determine their antioxidant defense system. Results imply that mud crabs may be subjected to environmental stresses that increase muscle detoxifying activities. Further studies are needed to explore the specific environmental factors that influence the expression patterns of SOD, GSH, and GST in mud crabs from different habitats.

The article can be obtained here: https://www.sciencedirect.com/science/article/abs/pii/S0048969724043584?via%3Dihub