C. elegans as a tool for environmental toxicology

Summary

We describe the utility of the free-living soil nematode Caenorhabditis elegans (C. elegans) as a model organism for toxicity tests. Dose response data were observed on larvae C. elegans exposed to xenobiotic chemicals, CdCl₂ and Bisphenol-A (BPA), under liquid toxicity test system. The end points measured were 5, 8, 24 hr mortality. The LD₅₀ value was low level or the same level in C. elegans, although a longer duration was needed in yeast toxicity test. For mortality, CdCl₂ was more toxic than BPA. In addition to measurement of mortality after chemical exposure, we analyzed the effects of xenobiotic chemicals at the molecular level in C. elegans. In order to identify genes that are differentially expressed as a consequence of toxic stress due to CdCl₂ or BPA, we used the cDNA microarray system to compare mRNA expression patterns in C. elegans. Using cDNA microarray technique, we found that a large number of target genes positively and negatively regulated by each chemicals in C. elegans. Chemicals affected gene expression for a diverse range of cellular functions and the differential gene expression pattern was observed between different chemical exposures. These data suggest that C. elegans is a suitable test organism for chemical bioassay of environmental xenobiotic chemicals.