Dataset Information

Gene expression profiling in the ovary of Queen conch (Strombus gigas) exposed to tributyltin-polluted environments in the British Virgin Islands

ABSTRACT: Ecotoxicogenomics in field experiments have yielded valuable mechanistic information for organisms present in polluted environments. The Queen conch (Strombus gigas) is a threatened species and populations are declining due to anthropogenic impact that includes pollution from boating activities. In the British Virgin Islands (BVI), local Queen conch populations have exhibited imposex, a condition in which both male and female gonadal characteristics are present and studies in the BVI suggest that tributyl tin (TBT), a chemical used in boat paint, is correlated to increased incidence imposex. This present study utilized a previously validated 8 x 15K Queen conch microarray to characterize the response of the ovarian transcriptome in conch found in polluted environments with high TBT in the BVIs. There polluted sites, Road Harbour (RH) and Trellis Bay (TB), are harbours with high boating activity while the reference sites, Guana Island (GI) and Anegada (AN), are areas with low boating activity. Microarray analysis revealed that there were 17 transcripts with high homology to known genes that were differentially expressed in the environments with high TBT and these included 6 induced and 11 down-regulated transcripts (p<0.01). These differentially expressed transcripts included phosphoenolpyruvate carboxylase, transposase, and high-affinity phosphate transporter PT1. When considering both RH and TB together in comparison to GI, functional enrichment showed that the biological processes and molecular functions of calcium ion binding, immune response, and negative regulation of cell proliferation were over represented in the polluted sites. Gene set enrichment analysis revealed that transcripts involved in the biological processes of general metabolism, immune, lipid metabolism, and stress were affected in polluted environments. Although difficult to directly link changes at the transcriptomics level to TBT in the harbour, this analysis provides novel insight into pathways impacted in regions that experience heavy boating activity in the BVIs.

ORGANISM(S): Aliger gigas

PROVIDER: GSE37549 | GEO | 2012/12/31

SECONDARY ACCESSION(S): PRJNA161519

REPOSITORIES: GEO

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Project description:Ecotoxicogenomics in field experiments have yielded valuable mechanistic information for organisms present in polluted environments. The Queen conch (Strombus gigas) is a threatened species and populations are declining due to anthropogenic impact that includes pollution from boating activities. In the British Virgin Islands (BVI), local Queen conch populations have exhibited imposex, a condition in which both male and female gonadal characteristics are present and studies in the BVI suggest that tributyl tin (TBT), a chemical used in boat paint, is correlated to increased incidence imposex. This present study utilized a previously validated 8 x 15K Queen conch microarray to characterize the response of the ovarian transcriptome in conch found in polluted environments with high TBT in the BVIs. There polluted sites, Road Harbour (RH) and Trellis Bay (TB), are harbours with high boating activity while the reference sites, Guana Island (GI) and Anegada (AN), are areas with low boating activity. Microarray analysis revealed that there were 17 transcripts with high homology to known genes that were differentially expressed in the environments with high TBT and these included 6 induced and 11 down-regulated transcripts (p<0.01). These differentially expressed transcripts included phosphoenolpyruvate carboxylase, transposase, and high-affinity phosphate transporter PT1. When considering both RH and TB together in comparison to GI, functional enrichment showed that the biological processes and molecular functions of calcium ion binding, immune response, and negative regulation of cell proliferation were over represented in the polluted sites. Gene set enrichment analysis revealed that transcripts involved in the biological processes of general metabolism, immune, lipid metabolism, and stress were affected in polluted environments. Although difficult to directly link changes at the transcriptomics level to TBT in the harbour, this analysis provides novel insight into pathways impacted in regions that experience heavy boating activity in the BVIs. Adult female queen conchs were collected from field sites in the British Virgin Islands with varying levels of TBT contamination and imposex incidence. Contaminated sites included Rhode Harbour (RH, n=3) and Trellis Bay (TB, n=3), and the low-pollution site was Guana Island (GA, n=5). Ovaries were preserved in RNAlater, transported to the laboratory, and RNA was prepared using a phenol-chloroform extraction and a CsCl gradient. RNA was labeled with Cy3 for a single-dye design, per the Agilent protocol.

Project description:Thicklip grey mullet hepatic transcriptome comparission from PASAIA harbour, Basque Country Active biomonitoring using sentinel species caged in differentially polluted aquatic environments is being implemented worldwide. To determine the biological effects of pollutants in a heavily polluted Basque harbour (Pasaia, 431700N 015500W), two cages specially designed to deploy thicklip grey mullets (Chelon labrosus) were placed in the inner- and outer-harbour. Cages were deployed for 5 and 21 days to determine possible differences between sites, linked to specific chemical burdens. Hepatic gene expression profiles were studied using Q-PCR and a toxicology tailored low density mullet microarray (160 genes). Chemical analysis showed high concentrations of metals, PAHs, PCBs, phthalates, and organometallic compounds at both sites, most chemicals showing slightly higher concentrations in the inner-harbour. Q-PCR expression studies confirmed chemical data as metallothionein and CYP1A showed significant expression upregulation at day 21 at both sites, but showed no differences between sites. The microarray showed gene expression profiles that were able to distinguish mullets according to the site they were deployed in and the day they were captured. Regarding sites, 39 genes showed significant differences at p<0.05 on the last sampling day. Two families of genes are to be highlighted. Phase I and II biotransformation genes CYP2, CYP3 and UGT were upregulated in the inner-harbour together with AhR2 and AhRR. Similarly, TBT binding protein and genes involved in lipid metabolism such us PPARa and CYP7 were upregulated. The latter two genes have also been reported to be regulated by TBT. In summary, the low density microarray designed for mullets proved to be useful to unveil even slight differences in pollutant burdens in field conditions. 24 samples:6 hepatic samples from Inner harbour after 3 days of exposure, 6 hepatic samples from outer harbour after 3 days of exposure, 6 hepatic samples from Inner harbour after 15 days of exposure and 6 hepatic samples from outer harbour after 15 days of exposure

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Gene expression profiling in the ovary of Queen conch (Strombus gigas) exposed to tributyltin-polluted environments in the British Virgin Islands

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