Thiol oxidation of hemolymph proteins in oysters Crassostrea brasiliana as markers of oxidative damage induced by urban sewage exposure

Abstract

Urban sewage is a concerning issue worldwide, threatening both wildlife and human health. The present study investigated protein oxidation in mangrove oysters (Crassostrea brasiliana) exposed to seawater from Balneário Camboriú, an important tourist destination in Brazil that is affected by urban sewage. Oysters were exposed for 24 h to seawater collected close to the Camboriú River (CAM1) or 1 km away (CAM2). Seawater from an aquaculture laboratory was used as a reference. Local sewage input was marked by higher levels of coliforms, nitrogen, and phosphorus in seawater, as well as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), linear alkylbenzenes (LABs), and fecal steroid in sediments at CAM1. Exposure of oysters to CAM1 caused marked bioaccumulation of LABs and decreased PAH and PCB concentrations after exposure to both CAM1 and CAM2. Protein thiol oxidation in gills, digestive gland, and hemolymph was evaluated. Lower levels of reduced protein thiols were detected in hemolymph from CAM1, and actin, segon, and dominin were identified as targets of protein thiol oxidation. Dominin susceptibility to oxidation was confirmed in vitro by exposure to peroxides and hypochlorous acid, and 2 cysteine residues were identified as potential sites of oxidation. Overall, these data indicate that urban sewage contamination in local waters has a toxic potential and that protein thiol oxidation in hemolymph could be a useful biomarker of oxidative stress in bivalves exposed to contaminants. Environ Toxicol Chem 2017;36:1833-1845. © 2016 SETAC.

Extracellular Vesicles and Post-Translational Protein Deimination Signatures in Mollusca—The Blue Mussel (Mytilus edulis), Soft Shell Clam (Mya arenaria), Eastern Oyster (Crassostrea virginica) and Atlantic Jacknife Clam (Ensis leei)

“…It is a major plasma glycoprotein, also associated with hemocytes, and has roles in host-defense and metal metabolism, as well as oyster shell formation [192][193][194]. Dominin has been identified as biomarker of oxidative stress due to being a target of protein thiol oxidation in relation to environmental contaminants [195]. Dominin is a multifaceted protein with diverse functions including sequestering metals to limit their availability to pathogens as part of host defense, has roles in antioxidation, as well as in wound repair [196].…”

Impact of Polycyclic Aromatic Hydrocarbon Accumulation on Oyster Health

“…The oyster M. gigas accumulated the most out of the three species with total PAH ranging from 184-6,899 ng/g dry weight, while the mussel and clam accumulated 21-1,093 and 78-720 ng/g dry weight, respectively. Due to the high lipid content of oysters, this species is thought to be an excellent bioindicator for lipophilic contaminants such as PAHs, polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) (Fisher et al, 2000;Bustamante et al, 2012a;Leon et al, 2013;Trevisan et al, 2016;Aguirre-Rubí et al, 2018a) and even organic metals such as tributyltin (Alzieu et al, 1986;Higuera-Ruiz and Elorza, 2011) and methyl-Hg (Metian et al, 2020).…”