Cell density influences antibiotic biosynthesis in Streptomyces clavuligerus

Article Abstract:

A high concentration of Streptomyces clavuligerus spores in the culture medium rapidly induces the synthesis of the antibiotics cephamycin C and clavulanic acid. The spores release a conditioning factor into the medium that activates secondary metabolism in the cells. The conditioning factor is heat tolerant and contains peptides and free amino acids. The spores of other Streptomyces and Bacillus species also stimulate the synthesis of the antibiotics.

Antibiotics, Physiological aspects, Observations, Spores (Bacteria), Bacterial spores

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Streptomyces peucetius daunorubicin biosynthesis gene, dnrF: sequence and heterologous expression

Article Abstract:

The daunorubicin biosynthesis gene of the Streptomyces peucetius is an antitumor agent used to treat cancers, but has severe side effects including heart damage. Expression of the gene was determined by bioconversion assay, and the results may enable hybrid antibiotics to be developed to better treat cancer with fewer side effects. The gene is a NADPH-dependent hydroxylase that causes hydroxylation of aklavinone to obtain epsilon-rhodomycinone.

Drug therapy, Cancer, Streptomycin, Daunorubicin

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The dnrM gene in Streptomyces peucetius contains a naturally occurring frameshift mutation that is suppressed by another locus outside of the daunorubicin-production gene cluster

Article Abstract:

A 2.7 BamHI fragment of the daunorubicin biosynthetic cluster in Streptomyces peucetius ATCC 29050 was found to contain the putative ORFs dnrL and dnrM. The deduced products of dnrL and dnrM show a high sequence similarity to several glucose-1-phosphate thymidylyl transferases and TDP-D-glucose dehydratases, respectively. The dnrM gene contains a frameshift in the DNA sequence that causes translation to terminate prematurely.

Analysis, Genetic aspects, Bacteria, Microbial mutation, Deoxy sugars

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