Transgenic RFP‐RPS‐30^UbL strain of the nematode Caenorhabditis elegans as a biomonitor for environmental pollutants

Abstract

Environmental pollutants are recognized as one of the major concerns for public health. The free‐living nematode Caenorhabditis elegans are widely used to evaluate the toxicity of environmental contaminants in biomonitoring researches. In the present study, a new transgenic strain, rps‐30−/−;RFP‐RPS‐30UbL was generated, with constitutively active rps‐30 promoter used to control the expression of RFP‐RPS‐30UbL fusion protein. We found RFP‐RPS‐30UbL would accumulate to form ‘rod‐like’ structures, when worms were exposed to environmental contaminants, including Cd, Hg, Pb, As, Paraquat and Dichlorvos. The number of the ‘rod‐like’ structures was induced by environmental contaminants in a concentration‐ and time‐dependent manner. The ‘rod‐like’ structure formation could be detectable in response to the concentration of each contaminant as low as 24‐h LC50 × 10−7, and the detectable time could be within 2 h. Detecting the transcription and expression levels of RFP‐RPS‐30UbL in worms exposed to different kinds of environmental contaminants showed that the expression level of RFP‐RPS‐30UbL was not regulated by environmental contaminants, and the number differences of ‘rod‐like’ structures were just due to the morphological change of RFP‐RPS‐30UbL from dispersion to accumulation induced by environmental contaminants. In addition, this transgenic strain was developed in rps‐30−/− homozygous worm, which was a longevity strain. Detection of lifespan and brood size showed that rps‐30−/−;RFP‐RPS‐30UbL transgenic worm was more suitable to be cultured and used further than N2;GFP‐RPS‐30UbL, for expressing RPS‐30UbL in wild type N2 worms shortened the lifespan and deceased the brood size. Therefore, rps‐30−/−;RFP‐RPS‐30UbL transgenic worm might play a potential role in versatile environmental biomonitoring, with the advantage of not only the convenient and quick fluorescence‐based reporter assay, but also the quantificational evaluation of the toxicities of environmental contaminants using ‘rod‐like’ structures with high sensitivity, off‐limited the expression level of the reporter protein.