Project description:Xiangjiang River (Hunan, China) has been contaminated with heavy metal for several decades by surrounding factories. However, little is known about the influence of a gradient of heavy metal contamination on the diversity, structure of microbial functional gene in sediment. To deeply understand the impact of heavy metal contamination on microbial community, a comprehensive functional gene array (GeoChip 5.0) has been used to study the functional genes structure, composition, diversity and metabolic potential of microbial community from three heavy metal polluted sites of Xiangjiang River.
Project description:Xiangjiang River (Hunan, China) has been contaminated with heavy metal for several decades by surrounding factories. However, little is known about the influence of a gradient of heavy metal contamination on the diversity, structure of microbial functional gene in sediment. To deeply understand the impact of heavy metal contamination on microbial community, a comprehensive functional gene array (GeoChip 5.0) has been used to study the functional genes structure, composition, diversity and metabolic potential of microbial community from three heavy metal polluted sites of Xiangjiang River. Three groups of samples, A, B and C. Every group has 3 replicates.
Project description:To explore how gene expression translates to developmental phenotype in both sensitive and resistant Fundulus embryos upon POP exposure, we exposed Fundulus embryos from the Elizabeth River Superfund population and the Magotha Bay, VA clean population to Elizabeth River polluted sediment extracts and measured chemical uptake, gene expression, and altered embryo anatomy, morphology and cardiac physiology during four critical developmental stages: somitogenesis, heart beat initiation, late organogenesis, and pre-hatching.
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:Toxicity of river sediments are assessed using whole sediment toxicity tests with benthic organisms. The challenge, however, is the differentiation between multiple effects caused by complex contaminant mixtures and the unspecific toxicity endpoints such as survival, growth or reproduction. Moreover, natural sediment properties, such as grain size distribution and organic carbon content, can influence the test parameters by masking pollutant toxicity. The use of gene expression profiling facilitates the identification of transcriptional changes at the molecular level that are specific to the bioavailable fraction of pollutants. The nematode Caenorhabditis elegans is ideally suited for these purposes, as (i) it can be exposed to whole sediments, and (ii) its genome is fully sequenced and widely annotated. In this pilot study we exposed C. elegans for 48 h to three sediments varying in degree of contamination with e.g. heavy metals and organic pollutants. Following the exposure period, gene expression was profiled using a whole genome DNA-microarray approach. Whole genome DNA microarray experiments were performed using a common reference design to identify differentially expressed genes in nematodes exposed to one of three river sediments of differing pollution level. Each sample consists of the 5 “biological replicates”.
Project description:Toxicity of river sediments are assessed using whole sediment toxicity tests with benthic organisms. The challenge, however, is the differentiation between multiple effects caused by complex contaminant mixtures and the unspecific toxicity endpoints such as survival, growth or reproduction. Moreover, natural sediment properties, such as grain size distribution and organic carbon content, can influence the test parameters by masking pollutant toxicity. The use of gene expression profiling facilitates the identification of transcriptional changes at the molecular level that are specific to the bioavailable fraction of pollutants. The nematode Caenorhabditis elegans is ideally suited for these purposes, as (i) it can be exposed to whole sediments, and (ii) its genome is fully sequenced and widely annotated. In this pilot study we exposed C. elegans for 48 h to three sediments varying in degree of contamination with e.g. heavy metals and organic pollutants. Following the exposure period, gene expression was profiled using a whole genome DNA-microarray approach.
Project description:The zebrafish embryo has repeatedly proved to be a useful model for the analysis of effects by environmental toxicants. This proof-of-concept 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 sediment extracts. For 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 considerably extend 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. Microarray analysis were performed with early life stages of zebrafish exposed to 2 sediment extracts from the Upper part of the River Rhine, Germany. The expression profile as then compared to the expression pattern of model toxicants, such as, 4-chloroaniline, Cadmium, DDT, TCDD, and Valproic acid (Gene Expression Omnibus Series GSE9357). Additionally, combining mechanism-specific bioassays as well as chemical analysis of the sediments to the gene expression data has contributed to a more comprehensive view on the hazard potential of the sediments.
Project description:We used the mummichog (Fundulus heteroclitus) array we developed to test whether our arrays could be used to monitor the efficacy of remediation at an estuarine Superfund site. Shipyard Creek is a chromium-contaminated Superfund site in Charleston, SC undergoing remediation, therefore it provides a unique opportunity to study the efficacy of arrays as a molecular biomarker in of toxicant effects in mummichogs. Mummichogs were captured in Shipyard Creek in Charleston, SC prior to remediation (2000), after remediation began (2003), and as remediation further progressed (2005). Simultaneously, mummichogs were collected from a reference site at the Winyah-Bay National Estuarine Research Reserve (NERR). The hepatic gene expression pattern of fish captured at Shipyard Creek showed wide differences from the fish captured at NERR in 2000. As remediation progressed the gene expression pattern of fish captured at Shipyard Creek became increasingly similar to fish captured at NERR, and the number of genes differently expressed dropped from 22 to 4. The magnitude of differential gene expression of the individual genes also decreased during remediation. The recovering gene expression profile is associated with lower chromium bioavailability, demonstrated through significantly decreased body burden and sediment concentrations. For example, sediment concentrations at Shipyard Creek were 80-fold greater than NERR in 2000, 51-fold greater in 2003, and only 8-fold greater in 2005. However, hydraulic dredging in 2005 stirred up the sediments and increased body burden of chromium even though chromium sediment concentrations continued to drop. Therefore, the number of differentially expressed genes increased to 9. Overall, the data supports our hypothesis that arrays can be used to monitor site mitigation, as the number of genes differentially expressed mimics the body burden and also indicates when on-site remediation is increasing bioavailability. Keywords: Field site
Project description:We used the mummichog (Fundulus heteroclitus) array we developed to test whether our arrays could be used to monitor the efficacy of remediation at an estuarine Superfund site. Shipyard Creek is a chromium-contaminated Superfund site in Charleston, SC undergoing remediation, therefore it provides a unique opportunity to study the efficacy of arrays as a molecular biomarker in of toxicant effects in mummichogs. Mummichogs were captured in Shipyard Creek in Charleston, SC prior to remediation (2000), after remediation began (2003), and as remediation further progressed (2005). Simultaneously, mummichogs were collected from a reference site at the Winyah-Bay National Estuarine Research Reserve (NERR). The hepatic gene expression pattern of fish captured at Shipyard Creek showed wide differences from the fish captured at NERR in 2000. As remediation progressed the gene expression pattern of fish captured at Shipyard Creek became increasingly similar to fish captured at NERR, and the number of genes differently expressed dropped from 22 to 4. The magnitude of differential gene expression of the individual genes also decreased during remediation. The recovering gene expression profile is associated with lower chromium bioavailability, demonstrated through significantly decreased body burden and sediment concentrations. For example, sediment concentrations at Shipyard Creek were 80-fold greater than NERR in 2000, 51-fold greater in 2003, and only 8-fold greater in 2005. However, hydraulic dredging in 2005 stirred up the sediments and increased body burden of chromium even though chromium sediment concentrations continued to drop. Therefore, the number of differentially expressed genes increased to 9. Overall, the data supports our hypothesis that arrays can be used to monitor site mitigation, as the number of genes differentially expressed mimics the body burden and also indicates when on-site remediation is increasing bioavailability. Keywords: Field site
Project description:We used the mummichog (Fundulus heteroclitus) array we developed to test whether our arrays could be used to monitor the efficacy of remediation at an estuarine Superfund site. Shipyard Creek is a chromium-contaminated Superfund site in Charleston, SC undergoing remediation, therefore it provides a unique opportunity to study the efficacy of arrays as a molecular biomarker in of toxicant effects in mummichogs. Mummichogs were captured in Shipyard Creek in Charleston, SC prior to remediation (2000), after remediation began (2003), and as remediation further progressed (2005). Simultaneously, mummichogs were collected from a reference site at the Winyah-Bay National Estuarine Research Reserve (NERR). The hepatic gene expression pattern of fish captured at Shipyard Creek showed wide differences from the fish captured at NERR in 2000. As remediation progressed the gene expression pattern of fish captured at Shipyard Creek became increasingly similar to fish captured at NERR, and the number of genes differently expressed dropped from 22 to 4. The magnitude of differential gene expression of the individual genes also decreased during remediation. The recovering gene expression profile is associated with lower chromium bioavailability, demonstrated through significantly decreased body burden and sediment concentrations. For example, sediment concentrations at Shipyard Creek were 80-fold greater than NERR in 2000, 51-fold greater in 2003, and only 8-fold greater in 2005. However, hydraulic dredging in 2005 stirred up the sediments and increased body burden of chromium even though chromium sediment concentrations continued to drop. Therefore, the number of differentially expressed genes increased to 9. Overall, the data supports our hypothesis that arrays can be used to monitor site mitigation, as the number of genes differentially expressed mimics the body burden and also indicates when on-site remediation is increasing bioavailability. Keywords: Field site