Project description:The diverse mixture of contaminants frequently present in estuarine wetlands complicates their assessment by routine chemical or biological analyses. We investigated the use of gene expression to assess contaminant exposure and the condition of southern California (USA) estuarine fish. Liver gene expression, plasma estradiol concentrations and gonad histopathology were used to investigate the biological condition of longjaw mudsuckers (Gillichthys mirabilis). A wide array of metals, legacy organochlorine pesticides, PCBs and contaminants of emerging concern were detected in sediments and whole fish. Overall gene expression patterns were characteristic to each of four sites investigated in this study. Differentially expressed genes belonged to several functional categories including xenobiotic metabolism, detoxification, disease and stress responses. In general, plasma estradiol concentrations were similar among fish from all areas. Some fish gonads had pathologic changes (e.g. infection, inflammation) that could indicate weakened immune systems and chronic stress. The differential expression of some genes involved in stress responses correlated with the prevalence of histologic gonad lesions. This study indicates that sentinel fish gene expression data is a promising tool for assessing the biological condition of fish exposed to environmental contaminants. Key Words: Gene expression, fish, contaminants, estuaries. This abstract belongs to a manuscript that has been submitted to Environmental Science and Technology. The manuscript has been invited as part of an especial Omics Issue which is expected to be published in 2012. In this study, we used hepatic gene expression in wild longjaw mudsuckers (Gillichthys mirabilis) to assess biological responses from anthropogenically influenced wetlands. We investigated the relationships among gene expression responses, chemical exposure and additional biological responses in this species. We studied estuarine wetlands that had diverse contaminant characteristics and received three main types of contaminant inputs in different proportions: agricultural runoff, urban runoff and municipal wastewater.
