Biological and chemical effects of mustard gas in yeast

Area of Science:

• Molecular Biology
• Genetics
• Toxicology

Background:

• Mustard gas is a chemical warfare agent known to cause cellular damage.
• Understanding its genotoxic mechanisms is crucial for risk assessment and mitigation.

Purpose of the Study:

• To investigate the effects of mustard gas on yeast cells, focusing on inactivation and mutation induction.
• To determine the role of DNA repair mechanisms in the cellular response to mustard gas exposure.

Main Methods:

• Dose-response experiments were conducted on yeast to assess inactivation and mutation.
• DNA dark-repair proficiency was evaluated in relation to mutation induction.
• Inter-strand cross-links were quantified using DNA renaturation assays.
• Chromatographic analysis identified DNA alkylation products.

Main Results:

• Mustard gas induced dose-proportional inactivation and mutation in yeast, suggesting single-hit events.
• Mutation induction was influenced by the cell's DNA dark-repair capacity, with higher rates in proficient cells.
• Mustard gas binding to cells and DNA was independent of DNA repair systems.
• A dose-proportional increase in DNA inter-strand cross-links was observed, with 55 cross-links found at 37% survival in an excision-deficient strain.
• Chromatographic analysis revealed DNA alkylation products with frequencies similar to those in E. coli and bacteriophage T7.

Conclusions:

• Mustard gas is a potent genotoxic agent in yeast, inducing mutations and inactivation via single-hit mechanisms.
• Cellular DNA repair capacity modulates the mutagenic outcome of mustard gas exposure.
• The formation of DNA inter-strand cross-links is a key event in mustard gas-induced genotoxicity.