Project description:Marine sediments harbor highly diverse microbial communities that contribute to global biodiversity and play essential roles in the ecosystem functioning. However, the metaproteome of marine sediments remains poorly understood. Extracting proteins from environmental samples can be challenging, especially in marine sediments due to their complex matrix. Few studies have been conducted on improving protein extraction methods from marine sediments. To establish an effective protein extraction workflow for clay-rich sediments, we compared, combined and improved several protein extraction methods. The presented workflow includes blocking of protein binding sites on sediment particles with high concentrations of amino acids, effective cell lysis via ultra-sonication, and the electro-elution and simultaneous fractionation of proteins. Using this workflow, we were able to recover 100% of the previously added Escherichia coli proteins from the sediment.
Project description:The objective was to identify functional genes encoded by Fungi and fungal-like organisms to assess putative ecological roles Using the GeoChip microarray, we detected fungal genes involved in the complete assimilation of nitrate and the degradation of lignin, as well as evidence for Partitiviridae (a mycovirus) that likely regulates fungal populations in the marine environment. These results demonstrate the potential for fungi to degrade terrigenously-sourced molecules, such as permafrost and compete with algae for nitrate during blooms. Ultimately, these data suggest that marine fungi could be as important in oceanic ecosystems as they are in freshwater environments.
Project description:Chemical analysis of the compounds present in sediment, although informative, often is not indicative of the downstream biological effects that these contaminants exert on resident aquatic organisms. More direct molecular methods are needed to determine if marine life is affected by exposure to sediments. In this study, we used an aquatic multispecies microarray and q-PCR to investigate the effects on gene expression in juvenile sea bream (Sparus aurata) of two contaminated sediments defined as sediment 1 and 2 respectively, from marine areas in Northern Italy.
Project description:Marine cyanobacteria are thought to be the most sensitive of the phytoplankton groups to copper toxicity, yet little is known of the transcriptional response of marine Synechococcus to copper shock. Global transcriptional response to two levels of copper shock was assayed in both a coastal and an open ocean strain of marine Synechococcus using whole genome expression microarrays. Both strains showed an osmoregulatory-like response, perhaps as a result of increasing membrane permeability. This could have implications for marine carbon cycling if copper shock leads to dissolved organic carbon leakage in Synechococcus. The two strains additionally showed a reduction in photosynthetic gene transcripts. Contrastingly, the open ocean strain showed a typical stress response whereas the coastal strain exhibited a more specific oxidative or heavy metal type response. In addition, the coastal strain activated more regulatory elements and transporters, many of which are not conserved in other marine Synechococcus strains and may have been acquired by horizontal gene transfer. Thus, tolerance to copper shock in some marine Synechococcus may in part be a result of an increased ability to sense and respond in a more specialized manner.