Physiological effects of temperature and a herbicide mixture on the soft‐shell clam Mya arenaria (Mollusca, Bivalvia)

Abstract

Abstract-The aim of the current study was to investigate effects of temperature and a mixture of herbicides on the physiological status of the bivalve Mya arenaria. Bivalves acclimated to two temperatures (7 and 188C) were exposed for 28 d to 0.01 mg/L of a pesticide formulation containing dichlorophenoxyacetic acid (2,4-D), 2-(2-methyl-4-chlorophenoxy) propionic acid (mecoprop), and 3,6-dichloro-2-methoxybenzoic acid (dicamba). At days 7, 14, and 28, mortality, immune parameters (hemocyte number, phagocytic activity, and efficiency), biomarkers of oxidative stress (catalase [CAT] and superoxide dismutase [SOD] activities and malondialdehyde [MDA] content), the metabolic enzyme cytochrome C oxidase (CCO), a biomarker of pesticide exposure (acetylcholinesterase [AChE]), and the activity of an enzyme related to gametogenesis (aspartate transcarbamylase [ATCase]) were monitored in clam tissues. Gonadosomatic index (GSI), condition factor (CF), and sex were also assessed. In clams acclimated to 78C, exposure to pesticide enhanced CCO activity and CF and decreased MDA content, hemocyte number, CAT, and SOD activities. In clams kept at 188C, pesticide effects appeared minor compared with samples kept at 78C. In bivalves acclimated to 188C, CCO, SOD, and ATCase activity and MDA content were enhanced, and hemocyte number, CAT, and AchE activities and phagocytosis were suppressed. In samples exposed to pesticides, increased temperature enhanced MDA content and CCO and SOD activity and suppressed hemocyte number and CAT and AchE activity. A gradual sexual maturation was observed in both sexes through experimental time, but females had a higher sensitivity to temperature and pesticides compared to males. Increased temperature altered the ability of the sentinel species Mya arenaria to respond to pesticide exposures. Further work is needed to understand the impacts of increasing temperature on the whole St. Lawrence estuary ecosystem. Environ. Toxicol. Chem. 2011;30:132-141. # 2010 SETAC

Cultured heart cells from oyster : an experimental approach for evaluation of the toxicity of the marine pollutant tributyltin

“…Other in vitro models from marine invertebrates have also been used in marine ecotoxicological studies: oyster embryos (Galgani et al 2009;Mamindy-Pajany et al 2011), sponge primmorphs (Châtel et al 2011) and isolated invertebrate haemocytes (Anderson et al 1997;Cima et al 2004Cima et al , 2008Gopalakrishnan et al 2011;Greco et al 2011). In haemocytes, the study of pollutant effects demonstrated an alteration of parameters such as cell viability, phagocytotic activity, esterase activity or production of reactive oxygen species (Cima et al 2004;Gagnaire et al 2006;Gopalakrishnan et al 2011).…”

Effects of Pesticides on Marine Bivalves: What Do We Know and What Do We Need to Know?

“…shortterm bioassays with one or two test species). As an example, Greco et al (2010) investigating effects of a mixture of herbicides on the physiological status of the soft clam, Mya arenaria, showed that in clams kept at 18°C, pesticides appeared to induce minor effects compared with animals kept at 7°C. They concluded that increased temperature may modify the response of Mya arenaria to pesticides.…”

“…Studies carried out in adult Pacific cupped oysters revealed that diuron induces partial spawning and atrophy of the digestive epithelium after 1 week of exposure at 1 µg L -1 (Buisson et al, 2008). Greco et al (2010) investigated effects of a mixture of herbicides on the physiological status of the soft clam, Mya arenaria. Clams were exposed for 28 days to 0.01 mg L -1 of a pesticide mixture: dichlorophenoxyacetic acid (2,4-D), 2-(2-methyl-4-chlorophenoxy) propionic acid (mecoprop), and 3,6-dichloro-2-methoxybenzoic acid (dicamba).…”

Analysis of Gene Expression in an Inbred Line of Soft-Shell Clams (Mya arenaria) Displaying Growth Heterosis: Regulation of Structural Genes and the NOD2 Pathway

“…M. arenaria is a member of the phylum Mollusca, ranging throughout the northern, boreal coastline spanning several continents [1]. The clam is a filter-feeding bivalve, causing it to bioaccumulate environmental pollutants, and thus acts as a sentinel species [4]. In Maine, M. arenaria is harvested commercially, and, in 2015, the soft-shell clam fishery was the second most important in dockside value ($22.5 million) behind the American lobster, Homarus americanus ($495.4 million) [5].…”