title: Biotransformation and detoxification of inorganic arsenic in Bombay oyster Saccostrea cucullata.
abstract: Arsenic (As) exists as the toxic inorganic forms in marine water and sediment, while marine oysters usually accumulate high As contents mostly as the less toxic organic forms. It has not yet been clear that how As is biotransformed in marine oysters. This study therefore investigated the biotransformation and detoxification of two inorganic As forms (As(III) and As(V)) in Bombay oyster Saccostrea cucullata after waterborne exposures for 30 days. Seven treatments of dissolved As exposure (clean seawater, 1, 5, 20 mg/L As(III), and 1, 5, 20 mg/L As(V)) were performed. Body As concentration increased significantly after all As exposure treatments except 1mg/L As(V). Total As, As(III), and As(V) concentration were positive correlated with glutathione-S-transferases (GST) activities, suggesting GST might play an important role in the As biotransformation and detoxification process. Organic As species were predominant in control and the low As exposed oysters, whereas a large fraction of As was remained as the inorganic forms in the high As exposed oysters, suggesting As could be biotransformed efficiently in the oysters in clean or light contaminated environment. The results of As speciation demonstrated the As biotransformation in the oysters included As(V) reduction, methylation to monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), and subsequent conversion to arsenobetaine (AsB). More As was distributed in the subcellular metallothionein-like proteins fraction (MTLP) functioning sequestration and detoxification in the inorganic As exposed oysters, suggesting it was also a strategy for oysters against As stress. In summary, this study elucidated that marine oysters had high ability to accumulate, biotransform, and detoxify inorganic As.
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China.
authors.forename: Huaxue
authors.initials: H
authors.lastname: Liu
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China. Electronic address: zhangli@scsio.ac.cn.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001151:Arsenic / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity*; D001152:Arsenicals / Q000378:metabolism; D001711:Biotransformation; D002101:Cacodylic Acid / Q000378:metabolism; D008658:Inactivation, Metabolic; D008745:Methylation; D010125:Ostreidae / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism / Q000633:toxicity
chemical_list: D001152:Arsenicals; D014874:Water Pollutants, Chemical; D002101:Cacodylic Acid; C020300:monomethylarsonic acid; D001151:Arsenic; C038992:arsenobetaine
keywords: Arsenic; Biotransformation; Detoxification; Oyster; Speciation