The toxicity of dithiocarbamate fungicides to soil nematodes, assessed using a stress-inducible transgenic strain of Caenorhabditis elegans

✍ Scribed by Kemal Guven; Rowena S. Power; Sophia Avramides; Rebecca Allender; David I. de Pomerai

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 187 KB
• Volume: 13
• Category: Article
• ISSN: 1095-6670
• DOI: 10.1002/(sici)1099-0461(1999)13:6<324::aid-jbt6>3.0.co;2-q

✦ Synopsis

The dithiocarbamate fungicides maneb and mancozeb induce a short-term stress response in a transgenic Caenorhabditis elegans strain (PC72) carrying a reporter lacZ gene under the control of a homologous heat shock (hsp16) promoter. This response can be readily monitored as induced b-galactosidase activity, either by in situ staining or by a quantitative fluorometric enzyme assay. Particularly strong responses are induced by mancozeb (three-to fivefold above controls at 500 lg mL ‫1‬ ), causing acute toxicity at concentrations comparable to those recommended for field application (2 mg mL ‫1‬ ). Although much of this fungicide is adsorbed by soil, sufficient (ca. 6%) enters the soil water compartment to cause mild stress in the transgenic worm assay. Among possible metabolites from mancozeb breakdown, neither Mn ‫2‬ nor ethylenethiourea (ETU) is particularly toxic even at 10% of the optimum mancozeb dosage. Stress responses to a range of other pesticides are also reported, and in several cases it is clear that a nontarget soil species (here, transgenic C. elegans) may be sensitive to low-level contamination.