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The induction of mutants of Acinetobacter calcoaceticus NCIB8250 and their selection by vancomycin
Abstract:
The mutagenic and lethal effects of N-methyl-N'-nitro-N-nitrosoguanidine (NTG), ethyl methanesulphonate (EMS), ultraviolet light irradiation and near-ultraviolet light irradiation with 8-methoxypsoralen on the bacterium Acinetobacter calcoaceticus NCIB8250 were examined. The production of auxotrophic mutants was used as a measure of mutagenic efficiency. Under appropriate conditions all four agents were mutagenic. EMS and NTG although more effective than irradiation, did not cause such a high frequency of mutation as has been observed with other bacteria. A combination of vancomycin and penicillin V gave enrichment of non-metabolizing bacteria and optimum conditions were found for the use of these compounds in a selection technique.
Insights
This study investigated the mutagenic effects of four agents on Acinetobacter calcoaceticus, finding all were mutagenic. Ethyl methanesulphonate (EMS) and N-methyl-N’-nitro-N-nitrosoguanidine (NTG) were more effective than irradiation but less so than in other bacteria.
Area of Science:
- Microbiology
- Genetics
- Bacteriology
Background:
- Acinetobacter calcoaceticus is a bacterium relevant in various environments.
- Understanding mutagenic agents is crucial for microbial genetics and safety assessments.
Purpose of the Study:
- To evaluate the mutagenic and lethal effects of N-methyl-N'-nitro-N-nitrosoguanidine (NTG), ethyl methanesulphonate (EMS), UV, and near-UV with 8-methoxypsoralen on Acinetobacter calcoaceticus.
- To establish optimal conditions for mutant selection using antibiotics.
Main Methods:
- Exposure of Acinetobacter calcoaceticus NCIB8250 to four different mutagenic agents.
- Quantification of auxotrophic mutant production to assess mutagenic efficiency.
- Utilizing a combination of vancomycin and penicillin V for enrichment of non-metabolizing bacteria.
Main Results:
- All four tested agents (NTG, EMS, UV, near-UV with 8-methoxypsoralen) demonstrated mutagenic activity.
- EMS and NTG showed higher mutagenic effectiveness compared to UV irradiation.
- Mutation frequencies induced by EMS and NTG were lower than those reported for other bacterial species.
- Optimal conditions for antibiotic-based selection of non-metabolizing bacteria were determined.
Conclusions:
- N-methyl-N'-nitro-N-nitrosoguanidine (NTG), ethyl methanesulphonate (EMS), and UV irradiation are effective mutagens for Acinetobacter calcoaceticus.
- The study identified specific antibiotic combinations and conditions for efficient mutant selection in this bacterium.
- Comparative mutagenicity data for Acinetobacter calcoaceticus were established, highlighting differences from other bacterial models.