Project description:Arsenic and mercury are known chemical hazards. The differences in effects from organic and inorganic forms of these toxic elements is less well understood, however. The nematode Caenorhabditis elegans (C. elegans) is a suitable model to investigate the toxicity of environmental hazards. In this study, the transcriptomic profiles of C. elegans exposed to inorganic mercury chloride (HgCl2) and sodium (meta)arsenite (NaAsO2) were assessed alongside organic methylmercury chloride (meHgCl) and dimethylarsinic acid (DMA). For this purpose, adult C. elegans were exposed for 24 h to NaAsO2 (10 µg/ml), DMA (200 µg/ml), HgCl2 (2 µg/ml), and meHgCl (0.5 µg/ml), concentrations that were equitoxic in juveniles for developmental delay. Whole genome gene expression profiles were determined by using Cellegans_UnrestrictedGE_G2519F_020186 Microarray (Agilent Technologies, Santa Clara, CA). The results showed significant changes in the transcriptome of adult C. elegans exposed to NaAsO2, DMA, HgCl2, or meHgCl relative to the control group (C. elegans treated with water). A total of 927 and 1221 differentially expressed genes (DEGs) were found in C. elegans treated with 10 µg/ml NaAsO2 or 200 µg/ml DMA, respectively. Interestingly, only 161 DEGs were in common for these two chemicals. Exposure to 2 µg/ml HgCl2 or 0.5 µg/ml meHgCl altered the expression of 670 and 485 genes, respectively, and out of these genes, 154 were commonly altered by the two treatments. Analysis of DEGs revealed that organic and inorganic forms of arsenic and mercury have different effects on the transcriptome of adult C. elegans.
Project description:Humans are exposed to both inorganic and organic mercury. While the toxicity of mercury is well established, much remains to be resolved about how different mercurials act at the molecular level. To address this issue, we employed a toxicogenomics approach using the nematode C. elegans. Using sub-, low- or high-toxic exposures of either HgCl2 or CH3HgCl the effects of these mercurials on steady-state mRNA levels for the entire genome were determined. A total of 473 and 2,865 genes were differentially expressed in the HgCl2 and CH3HgCl treatments, respectively. Hierarchical clustering, principal components and pattern analyses indicated that the transcriptional responses of the mercurials were unique.
Project description:Humans are exposed to both inorganic and organic mercury. While the toxicity of mercury is well established, much remains to be resolved about how different mercurials act at the molecular level. To address this issue, we employed a toxicogenomics approach using the nematode C. elegans. Using sub-, low- or high-toxic exposures of either HgCl2 or CH3HgCl the effects of these mercurials on steady-state mRNA levels for the entire genome were determined. A total of 473 and 2,865 genes were differentially expressed in the HgCl2 and CH3HgCl treatments, respectively. Hierarchical clustering, principal components and pattern analyses indicated that the transcriptional responses of the mercurials were unique. Mixed-stage C. elegans populations were exposed to 0, 2, 7.5 or 20 uM HgCl2 or 0, 0.75, 2, 7.5 uM CH3HgCl for 24 hours. Three independent experiments were performed for each treatment condition.
Project description:Although non-coplanar PCBs are ubiquitous organic chemicals known to induce numerous biological responses and thus are toxic to man and wildlife, little is known about the toxic mode of action. Using PCB52, an ortho-substituted, 2,2’,5,5’-tetrachlorobiphenyl, it was possible to pinpoint the relationship between induced gene expression and observed toxicity in the model nematode Caenorhabditis elegans. Keywords: stress response
Project description:Effective toxicological testing of the vast number of new and existing chemicals currently in use will require efficient and cost effective methods. We evaluated the utility of a simple, low cost toxicity testing system employing the nematode Caenorhabditis elegans to identify toxicologically relevant changes in gene expression. The objective of this research is to determine genomic and proteomic responses in the model nematode C. elegans to exposures to representatives of several classes of toxic industrial chemicals/materials (TICs/TIMs). A total of 3 chemicals (acrylamide, cadmium chloride, and mercuric chloride) were used in these experiments. Affymetrix GeneChip for C. elegans was used to examine genome-wide responses in the 19,000+ genes of this model organism. Mid-vulval L4 worms were exposed to one of four concentrations of acrylamide, cadmium or mercury for 4h and 8h. Exposures were performed in triplicate.