The toxicity of dithiocarbamate fungicides to soil nematodes, assessed using a stress-inducible transgenic strain of Caenorhabditis elegans.
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 beta-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 microg 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 Mn2+ 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.
Guven
K
K
Biology Department, Science Faculty, Dicle University, Diyarbakir, Turkey.
Power
R S
RS
Avramides
S
S
Allender
R
R
de Pomerai
D I
DI
D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D004121:Dimethyl Sulfoxide / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D005659:Fungicides, Industrial / Q000737:chemistry / Q000633:toxicity*; D008344:Maneb / Q000737:chemistry / Q000633:toxicity*; D008345:Manganese / Q000032:analysis; D020149:Manganese Poisoning; D030781:Organisms, Genetically Modified; D012987:Soil; D013312:Stress, Physiological / Q000503:physiopathology*; D018675:Toxicity Tests; D015032:Zinc / Q000032:analysis / Q000633:toxicity; D015038:Zineb / Q000737:chemistry / Q000633:toxicity; D001616:beta-Galactosidase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
D005659:Fungicides, Industrial; D012987:Soil; D008344:Maneb; D008345:Manganese; D001616:beta-Galactosidase; D015032:Zinc; C013099:mancozeb; D015038:Zineb; D004121:Dimethyl Sulfoxide