Biodiversity and identification of proteins in oyster inhabited in the East coast of the Gulf of Thailand and its application in marine environmental research
Abstract:
Current research project aimed to investigate the effect of environmental pollutant to oyster Saccostrea cucullata. DDT (dichlorodiphenyltrichloroethane), an organotin compound, was used to assess its toxicological effect to oyster. Experimental exposures were carried out to assess DDT effect to larva development, adult oyster and its tissues. Proteome analyses were performed in order to explore molecular basis of proteome response in both mantle tissue and secreted mucus after DDT exposures. Additionally, protein biomarkers of DDT exposure were also investigated. Histological techniques and proteome technology were used in current work. Results showed that DDT highly affected early life stages of oyster larva including gastrula, trochophore and D-shape veliger even in the lowest treated group as 0.25 μg/L. In adults, DDT caused mortality effect with LC50 at 96 hours of 891.25 μg/L. Histological results revealed that DDT impacted on tissue structure of DDT treated groups including 10 and 100 μg/L at 96 hours of exposure. Tissue inflammations were generally found. DDT also particularly induced hyperplasia in gills, induced mucous cell production in mantle and affected epithelium structure of digestive glands. Severity of particular symptoms were according to dose and time of exposures. Proteome results showed that DDT affected proteins in various groups including energy metabolism, protein production, cytoskeletons, ion transport, stress response and gas-exchange. Results obtained from current work revealed molecular basis of cellular response against DDT exposure in the oyster. Additionally, potential protein biomarkers of DDT exposure were also proposed in this study. This research project also extended the study to the measurement of butyltin compounds, organotin compounds, which have been reported as pollutants in the east coast. Tissues of the Green mussel Perna viridis was used for butyltin analyses. Results showed that butyltin compounds were measured in mussels with mean accumulation level of 2.66 ng/g dry weights which was equivalent to 0.49 ng/g wet weights. The mean bioaccumulation levels of mussel collected from Chonburi, Rayong and Trat Provinces were 1.04, 5.98 and 0.95 ng/g dry weight in which equivalent to 0.23, 1.10 and 0.15 ng/g wet weight basis. Our results indicated that bioaccumulations of butyltin compounds in mussels were extremely decreased comparing to previous reports. However, the monitoring should be further investigated because these compounds are persistent organic pollutants (POPs) and could be persist in environment for long period of time