Microbial short-term assays with thiram in vitro

Area of Science:

• Environmental toxicology
• Microbial genetics
• Chemical mutagenesis

Background:

• Fungicides are widely used in agriculture, necessitating toxicological evaluation.
• Thiram is a common fungicide with potential environmental and health impacts.
• Understanding the genotoxic potential of thiram is crucial for risk assessment.

Purpose of the Study:

• To assess the in vitro genotoxicity of the fungicide thiram.
• To evaluate thiram's effects on DNA repair and gene mutation in microbial systems.
• To investigate the role of metabolic activation in thiram's genotoxic activity.

Main Methods:

• In vitro assays including prophage lambda induction in Escherichia coli K12.
• Bacterial repair tests using Salmonella typhimurium strains TA1538 and TA1978.
• Gene mutation induction in Aspergillus nidulans (methA1 suppressor induction).
• Tests were conducted with and without metabolic activation.

Main Results:

• Thiram tested positive in the Salmonella typhimurium repair test.
• A 4-6 fold increase in forward mutations was observed in Aspergillus nidulans.
• Thiram induced prophage lambda in Escherichia coli K12 with metabolic activation.
• Genotoxicity was observed in the absence of metabolic activation.

Conclusions:

• Thiram exhibits genotoxic potential, demonstrated by its ability to induce DNA damage and mutations in microbial systems.
• The fungicide is mutagenic in bacterial repair and fungal mutation assays.
• Metabolic activation may influence the genotoxic effects of thiram.