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Actinomycin biosynthesis by protoplasts derived from Streptomyces parvulus
Abstract:
Conditions are described for the formation of protoplasts from Streptomyces parvulus that are able to synthesize actinomycin D de novo. Antibiotic synthesis by protoplasts, in contrast to that by mycelium, was sensitive to inhibition by actinomycin D and to a decrease in sucrose concentration. On the other hand, synthesis by mycelium was much more sensitive to inhibition by amino acid analogs (d-valine, cis-3-methylproline, and alpha-methyl-dl-tryptophan). In addition, the uptake of amino acids (l-methionine, sarcosine, and l- and d-valine) by protoplasts was significantly lower than that by mycelium. The advantages and limitations of using protoplasts for studying in vivo actinomycin synthesis are discussed.
Insights
Protoplasts from Streptomyces parvulus can synthesize actinomycin D, but their antibiotic production is sensitive to actinomycin D and sucrose levels. Mycelium showed higher sensitivity to amino acid analogs and greater amino acid uptake.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Streptomyces parvulus is a key producer of the antibiotic actinomycin D.
- Understanding the de novo synthesis of actinomycin D is crucial for optimizing antibiotic production.
- Protoplasts offer a unique cellular system for studying microbial metabolism.
Purpose of the Study:
- To characterize actinomycin D de novo synthesis in Streptomyces parvulus protoplasts.
- To compare the metabolic characteristics of protoplasts and mycelia in relation to antibiotic production.
- To evaluate the utility of protoplasts for in vivo actinomycin synthesis studies.
Main Methods:
- Formation of Streptomyces parvulus protoplasts.
- Cultivation of protoplasts and mycelia under varying conditions (actinomycin D, sucrose, amino acid analogs).
- Measurement of actinomycin D synthesis and amino acid uptake.
Main Results:
- Protoplast-mediated actinomycin D synthesis was sensitive to actinomycin D and reduced sucrose concentrations.
- Mycelial synthesis was more susceptible to inhibition by amino acid analogs.
- Protoplasts exhibited significantly lower amino acid uptake compared to mycelia.
Conclusions:
- Streptomyces parvulus protoplasts can be used to study de novo actinomycin D synthesis.
- Protoplast and mycelial metabolic pathways differ in their sensitivity to inhibitors and substrate availability.
- Protoplasts present both advantages and limitations for investigating in vivo actinomycin synthesis.