Project description:Members of the bacterial phylum Spirochaetes are primarily studied for their commensal and pathogenic roles in animal hosts. However, Spirochaetes are also frequently detected in anoxic hydrocarbon-contaminated environments but their ecological role in such ecosystems has so far remained unclear. Here we provide a functional trait to these frequently detected organisms with an example of a sulfate-reducing, naphthalene-degrading enrichment culture consisting of a sulfate-reducing deltaproteobacterium Desulfobacterium naphthalenivorans and a novel spirochete Rectinema cohabitans. Using a combination of genomic, proteomic, and physiological studies we show that R. cohabitans grows by fermentation of organic compounds derived from biomass from dead cells (necromass). It recycles the derived electrons in the form of H2 to the sulfate-reducing D. naphthalenivorans, thereby supporting naphthalene degradation and forming a simple microbial loop. We provide metagenomic evidence that equivalent associations between Spirochaetes and hydrocarbon-degrading microorganisms are of general importance in hydrocarbon- and organohalide-contaminated ecosystems. We propose that environmental Spirochaetes form a critical component of a microbial loop central to nutrient cycling in subsurface environments. This emphasizes the importance of necromass and H2-cycling in highly toxic contaminated subsurface habitats such as hydrocarbon-polluted aquifers.
Project description:Gene expression microarrays were performed to investigate the molecular effects of exposure to environmental polluted groundwater. Zebrafish was treated with polluted waters collected from dumps located upstream and downstream a sanitary landfills. Gene expression profiling of zebrafish liver was analyzed after acute exposure to sampled waters.
Project description:Gene expression microarrays were performed to investigate the molecular effects of exposure to environmental polluted groundwater. Mice were treated with polluted waters collected from dumps located upstream and downstream a sanitary landfills. Gene expression profiling of mouse liver was analyzed after acute and chronic exposure to sampled waters.
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.
2012-12-31 | GSE37549 | GEO
Project description:Metagenomic analysis of hydrocarbon polluted soils of Kuwait