Related Experiment Videos
Mutagenesis of Micromonospora rosaria by using protoplasts and mycelial fragments
Abstract:
Both mycelial fragments and protoplasts were successfully employed for mutagenesis of Micromonospora rosaria NRRL 3718, and the results were compared. The optimal conditions and effective procedures for mutagenesis of M. rosaria by a chemical mutagen, N-methyl-N'-nitro-N-nitrosoguanidine, have been determined. Mutation was efficiently induced when mycelial fragments were treated with N-methyl-N'-nitro-N-nitrosoguanidine at a concentration of 0.3 to 0.5 mg/ml in the reaction buffer of pH 7.0. Optimal treatment time was 20 to 40 min. Ampicillin treatment was very effective for enrichment of auxotrophs. Protoplasts showed much higher sensitivity to the lethal effect of N-methyl-N'-nitro-N-nitrosoguanidine. Although protoplasts have some advantage of single cell characteristics, the frequency of auxotrophs obtained was somewhat lower. Up to 4% of the colonies were shown to be auxotrophs under the well-defined conditions. This mutagenesis method with protoplasts or fragmented mycelia (or both) should be applicable to other actinomycetes that have limited or no sporulation.
Insights
Mutagenesis of Micromonospora rosaria using N-methyl-N'-nitro-N-nitrosoguanidine was optimized for both mycelial fragments and protoplasts. This method efficiently generates auxotrophs and is applicable to other actinomycetes.
Area of Science:
- Microbiology
- Molecular Biology
- Biotechnology
Background:
- Micromonospora rosaria is an important actinomycete genus with potential biotechnological applications.
- Efficient mutagenesis is crucial for genetic improvement of industrial microorganisms.
- Developing robust mutagenesis protocols for actinomycetes, especially those with limited sporulation, is a significant challenge.
Purpose of the Study:
- To compare the effectiveness of mutagenesis using mycelial fragments versus protoplasts of Micromonospora rosaria NRRL 3718.
- To determine optimal conditions for chemical mutagenesis using N-methyl-N itro-N-nitrosoguanidine (NTG).
- To establish a reliable method for generating auxotrophic mutants in M. rosaria.
Main Methods:
- Mycelial fragments and protoplasts of M. rosaria NRRL 3718 were subjected to mutagenesis.
- Chemical mutagenesis was performed using N-methyl-N itro-N-nitrosoguanidine (NTG) under varying concentrations, pH, and treatment times.
- Ampicillin enrichment was employed to isolate auxotrophic mutants.
- Sensitivity of protoplasts and mycelial fragments to NTG was assessed.
Main Results:
- Optimal NTG concentration for mycelial fragment mutagenesis was 0.3-0.5 mg/ml at pH 7.0, with treatment times of 20-40 minutes.
- Protoplasts exhibited higher sensitivity to NTG's lethal effects compared to mycelial fragments.
- While protoplasts offer single-cell advantages, mutagenesis frequency of auxotrophs was lower than with mycelial fragments.
- Up to 4% auxotrophic mutants were obtained under optimized conditions.
Conclusions:
- Both mycelial fragments and protoplasts are viable options for M. rosaria mutagenesis, with specific advantages for each.
- Optimized NTG treatment protocols provide an effective means for generating auxotrophic mutants in M. rosaria.
- The developed mutagenesis strategy is potentially applicable to other actinomycetes lacking efficient sporulation, facilitating their genetic manipulation.