Effects of Antifouling Biocides on Molecular and Biochemical Defense System in the Gill of the Pacific Oyster Crassostrea gigas

Abstract

Antifouling biocides such as organotin compounds and their alternatives are potent toxicants in marine ecosystems. In this study, we employed several molecular and biochemical response systems of the Pacific oyster Crassostrea gigas to understand a potential mode of action of antifouling biocides (i.e. tributyltin (TBT), diuron and irgarol) after exposure to different concentrations (0.01, 0.1, and 1 μg L-1) for 96 h. As a result, all the three antifouling biocides strongly induced the antioxidant defense system. TBT reduced both enzymatic activity and mRNA expression of Na+/K+-ATPase and acetylcholinesterase (AChE). Lower levels of both Na+/K+-ATPase activity and AChE mRNA expression were observed in the diuron-exposed oysters compared to the control, while the irgarol treatment reduced only the transcriptional expression of AChE gene. We also analyzed transcript profile of heat shock protein (Hsp) superfamily in same experimental conditions. All antifouling biocides tested in this study significantly modulated mRNA expression of Hsp superfamily with strong induction of Hsp70 family. Taken together, overall results indicate that representative organotin TBT and alternatives have potential hazardous effects on the gill of C. gigas within relatively short time period. Our results also suggest that analyzing a series of molecular and biochemical parameters can be a way of understanding and uncovering the mode of action of emerging antifouling biocides. In particular, it was revealed that Pacific oysters have different sensitivities depend on the antifouling biocides.

Impacts of the combined exposure to seawater acidification and arsenic on the proteome of Crassostrea angulata and Crassostrea gigas

“…For instance, Zhang et al (2015b) observed increased levels of several sHsps in C. gigas exposed to thermal stress, whilst no alteration in the same proteins were observed in oysters exposed to hypoosmotic stress or aerial exposure. Park et al (2016) also observed differential expression profiles of the gene expression of several Hsp families in response to different biofouling agents. Therefore, our results showing decreased expression of α-crystallin b could result from concerted regulation of Hsps in response to As exposure.…”

Significance and potential of marine microbial natural bioactive compounds against biofilms/biofouling: necessity for green chemistry

“…So far, organotins are the most effective methods of biofouling control; however, these chemicals are toxic to aquatic environments ( Yebra, Kiil & Dam-Johansen, 2004 ). The use of such toxic biocides presents environmental concerns involving anomalies in non-target organisms that include shell malformation in bivalves, depletion of oyster population, imposex in gastropods, and others ( Park et al, 2016 ). TBT has been labeled as the most lethal substance to have been deliberately introduced in to the marine environment by man ( Park et al, 2016 ).…”

“…The use of such toxic biocides presents environmental concerns involving anomalies in non-target organisms that include shell malformation in bivalves, depletion of oyster population, imposex in gastropods, and others ( Park et al, 2016 ). TBT has been labeled as the most lethal substance to have been deliberately introduced in to the marine environment by man ( Park et al, 2016 ). In general, the use of such toxins in marine environments poses a real threat to the marine biota ( Fleming et al, 2006 ).…”

Effects of Organotins on Crustaceans: Update and Perspectives

“…Since mollusks and crustaceans are important fisheries worldwide, many studies on OT accumulation and toxicity were developed in these animals ( 16 , 17 ). Marine bivalves (mussels, clams, and oysters) tend to accumulate higher OT levels than fishes or crustaceans ( 13 , 14 , 16 ). Tributyltin (TBT) and triphenyltin, the most toxic forms of OTs, are well-recognized endocrine-disrupting chemicals of mollusks causing imposex or masculinization of females in more than 200 species ( 4 , 13 , 18 , 19 ).…”

“…Marine bivalves (mussels, clams, and oysters) tend to accumulate higher OT levels than fishes or crustaceans ( 13 , 14 , 16 ). Tributyltin (TBT) and triphenyltin, the most toxic forms of OTs, are well-recognized endocrine-disrupting chemicals of mollusks causing imposex or masculinization of females in more than 200 species ( 4 , 13 , 18 , 19 ). Fishes and marine mammals can be contaminated either by drinking or by ingesting OTs-contaminated invertebrates.…”