Project description:Marine intertidal organisms commonly face hypoxic stress during low tide emersion; moreover, eutrophic conditions and sediment nearness could lead to hypoxic phenomena; it is indeed important to understand the molecular processes involved in the response to hypoxia. In this study the molecular response of the Pacific oyster Crassostrea gigas to prolonged hypoxia (2 mg O2 L-1 for 20 d) was investigated under experimental conditions. A transcriptomic approach was employed using a cDNA microarray of 9058 C. gigas clones to highlight the genetic expression patterns of the Pacific oyster under hypoxic conditions. Lines of oysters resistant (R) and susceptible (S) to summer mortality were used in this study. This is the first study employing microarrays to characterize the genetic markers and metabolic pathways responding to hypoxic stress in C. gigas.
Project description:Transcriptional profile comparison among Beijing and non-Beijing M. tuberculosis isolates. Three M. tuberculosis strains were compared. The laboratory reference strain, H37Rv, belongs to the Euro-American or lineage 4. Two clinical isolates of the East-Asian or lineage 2: 98_1663 is a pre-Beijing or Group 1 isolate, and HN878 is a Beijing or Group 5 isolate. Three replicates were performed for each comparison using two different biological samples.
Project description:<p>Deep-sea hydrothermal vents are unique ecosystems that may release chemically distinct dissolved organic matter to the deep ocean. Here, we describe the composition and concentrations of polar dissolved organic compounds observed in low and high temperature hydrothermal vent fluids at 9°50′N on the East Pacific Rise. The concentration of dissolved organic carbon was 46 µM in the low temperature hydrothermal fluids and 14 µM in the high temperature hydrothermal fluids. In the low temperature vent fluids, quantifiable dissolved organic compounds were dominated by water-soluble vitamins and amino acids. Derivatives of benzoic acid and the organic sulfur compound 2,3-dihydroxypropane-1-sulfonate (DHPS) were also present in low and high temperature hydrothermal fluids. The low temperature vent fluids contain organic compounds that are central to biological processes, suggesting that they are a by-product of biological activity in the subseafloor. These compounds may fuel heterotrophic and other metabolic processes at deep-sea hydrothermal vents and beyond.</p>
Project description:The zebrafish embryo has repeatedly proved to be a useful model for the analysis of effects by environmental toxicants. This study was performed to investigate if an approach combining mechanism-specific bioassays with microarray techniques can obtain more in-depth insights into the ecotoxicity of complex pollutant mixtures as present, e.g., in freeze-dried whole sediment samples and their corresponding organic extracts in parallel. To this end, altered gene expression was compared to data from established bioassays as well as to results from chemical analysis. Microarray analysis revealed several classes of significantly regulated genes which could to a considerable extent be related to the hazard potential. Results indicate that potential classes of contaminants can be assigned to sediment extracts by both classical biomarker genes and corresponding expression profile analyses of known substances. However, it is difficult to distinguish between specific responses and more universal detoxification of the organism. Additionally, different gene expression was shown to be less influenced by the sampling site than by the method of exposure, which could be attributed to differential bioavailability of contaminants. Microarray analyses were performed with early life stages of zebrafish exposed to sediment extracts or freeze-dried sediment from three sampling sites (Ehingen, Lauchert, Sigmaringen) along the Upper part of the Danube River, Germany. The expression profiles were compared within the sampling sites, between the exposure scheme and to the expression pattern of model toxicants, such as 4-chloroaniline, Cadmium, DDT, TCDD, and Valproic acid (Gene Expression Omnibus Series GSE9357). Additionally, mechanism-specific bioassays and chemical analysis of the sediments have been combined and compared to the present gene expression data.
Project description:The zebrafish embryo has repeatedly proved to be a useful model for the analysis of effects by environmental toxicants. This study was performed to investigate if an approach combining mechanism-specific bioassays with microarray techniques can obtain more in-depth insights into the ecotoxicity of complex pollutant mixtures as present, e.g., in freeze-dried whole sediment samples and their corresponding organic extracts in parallel. To this end, altered gene expression was compared to data from established bioassays as well as to results from chemical analysis. Microarray analysis revealed several classes of significantly regulated genes which could to a considerable extent be related to the hazard potential. Results indicate that potential classes of contaminants can be assigned to sediment extracts by both classical biomarker genes and corresponding expression profile analyses of known substances. However, it is difficult to distinguish between specific responses and more universal detoxification of the organism. Additionally, different gene expression was shown to be less influenced by the sampling site than by the method of exposure, which could be attributed to differential bioavailability of contaminants.
Project description:This SuperSeries is composed of the following subset Series: GSE22171: Pacific salmon gill samples: fate tracking in river, sampled in ocean GSE22177: Pacific salmon gill samples: fate tracking in river GSE22347: Pacific salmon gill samples: fate tracking at spawning grounds Refer to individual Series