Rifamycin XXV : a Group of Actinophages Active on Streptomyces mediterranei

Thiemann, J. E.; Hengeller, C.; Virgilio, A.

doi:10.1038/1931104a0

Cited by 15 publications

(9 citation statements)

References 2 publications

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“…The temperate phage liberated by the strain could, in rare instances, mutate to a virulent particle and thus result in the eventual lysis of the broth culture. A mutational origin of our various phages (except phage 156) from a common ancestor received some support from the results of the serological studies performed on them (Thiemann et al, 1964).…”

Section: Resultsmentioning

confidence: 94%

Rifamycin1

Thiemann¹,

Hengeller²,

Virgilio³

et al. 1964

Applied Microbiology

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XXXIII. Isolation of actinophages active on Streptomyces mediterranei and characteristics of phage-resistant strains. Appl. Microbiol. 12:261-268. 1964.-Five actinophages highly specific for Streptomyces mediterranei were isolated from lysed broth cultures. Studies were performed on the effect of plating conditions on plaque formation. The development of phage-resistant strains of S. mediterranei not only eliminated the phage but also significantly increased rifamycin yields. The phage-resistant cultures proved to be more unstable than the original sensitive strain. Maintenance of the cultures as frozen vegetative mycelium assured culture stability and reproducibility of the results. Strict aseptic precautions throughout the laboratories and fermentation areas did not eliminate the danger of phage infection; effective control was obtained only with the introduction of resistant strains. S. mediterranei phages proved to be highly specific for calcium as an adsorption cofactor; addition of calcium-sequestering agents to sensitive mycelium completely prevented its lysis by the phage. The resistant strains developed were capable of adsorbing the phage and of releasing it without multiplication upon aging of the mycelium. No marked morphological, cultural, or biochemical differences were found among the various phage-resistant strains. Actinophages active on streptomyces strains used in industrial fermentations have been known for several years. Saudek and Colingsworth (1947) were among the first to report an actinophage outbreak in the commercial production of streptomycin. Similar reports, dealing always with streptomycin fermentation, were published by other workers in the field (Reilly, Harris, and Waksman, 1947; Smith, Kuhn, and Miesel, 1947; Carvajal, 1953a). Weindling and Kapros (1951) reported for the first time a phage outbreak in chlortetracycline fermentation by a Streptomyces aureofaciens specific actinophage (Weindling, Tresner, and Backus, 1961). Recently, S. mediterranei, producer of rifamycin, was found to be lysed by a virulent and highly specific actinophage (Thiemann et al., 1962). In the present paper, some

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Section: Resultsmentioning

confidence: 94%

Rifamycin1

Thiemann¹,

Hengeller²,

Virgilio³

et al. 1964

Applied Microbiology

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“…To test this hypothesis, experiments of both EMSA and DNase I footprinting assay were performed, employing GlnRs and ect promoters from two important industrial strains of Amycolatopsis mediterranei and Streptomyces avermitilis that produce rifamycin (44) and avermectin (45), respectively. Both GlnRs (AME_GlnR and SAV_GlnR) were able to specifically bind to the ect promoters ( Fig.…”

Section: Figmentioning

confidence: 99%

GlnR-Mediated Regulation of ectABCD Transcription Expands the Role of the GlnR Regulon to Osmotic Stress Management

Shao

Deng

et al. 2015

J Bacteriol

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Ectoine and hydroxyectoine are excellent compatible solutes for bacteria to deal with environmental osmotic stress and temperature damages. The biosynthesis cluster of ectoine and hydroxyectoine is widespread among microorganisms, and its expression is activated by high salinity and temperature changes. So far, little is known about the mechanism of the regulation of the transcription of ect genes and only two MarR family regulators (EctR1 in methylobacteria and the EctR1-related regulator CosR in Vibrio cholerae) have been found to negatively regulate the expression of ect genes. Here, we characterize GlnR, the global regulator for nitrogen metabolism in actinomycetes, as a negative regulator for the transcription of ectoine/hydroxyectoine biosynthetic genes (ect operon) in Streptomyces coelicolor. The physiological role of this transcriptional repression by GlnR is proposed to protect the intracellular glutamate pool, which acts as a key nitrogen donor for both the nitrogen metabolism and the ectoine/ hydroxyectoine biosynthesis. IMPORTANCEHigh salinity is deleterious, and cells must evolve sophisticated mechanisms to cope with this osmotic stress. Although production of ectoine and hydroxyectoine is one of the most frequently adopted strategies, the in-depth mechanism of regulation of their biosynthesis is less understood. So far, only two MarR family negative regulators, EctR1 and CosR, have been identified in methylobacteria and Vibrio, respectively. Here, our work demonstrates that GlnR, the global regulator for nitrogen metabolism, is a negative transcriptional regulator for ect genes in Streptomyces coelicolor. Moreover, a close relationship is found between nitrogen metabolism and osmotic resistance, and GlnR-mediated regulation of ect transcription is proposed to protect the intracellular glutamate pool. Meanwhile, the work reveals the multiple roles of GlnR in bacterial physiology. Ectoine and its hydroxyl derivative hydroxyectoine are the most widely used compatible solutes in bacteria to cope with environmental high osmotic stress (1-4). Because these molecules are small soluble organic compounds, they can prevent water loss and promote water reentry into the cells (3, 5). In addition, these compounds can also help stabilize proteins and protect bacteria from heat (6, 7) and cold (8, 9) damage. Also, with their excellent behavior in protein stabilization, ectoine and hydroxyectoine have been adopted in many industrial applications, e.g., in scientific research, cosmetics, and medical applications (3, 10-13).So far, the biosynthetic pathway of ectoine and hydroxyectoine has been thoroughly studied, and a total of four genes, ectABCD, are found to be involved in the processes (1,6,14,15). Specifically, L-aspartate-␤-semialdehyde is catalyzed into ectoine by a threestep enzymatic reaction, employing L-2,4-diaminobutyric acid transaminase (EctB), N-␥-acetyltransferase (EctA), and ectoine synthase (EctC). In some bacteria that contain ectD, encoding the ectoine hydroxylase, ectoine is hydroxylate...

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“…Since SAIJDEK and COLINGTHWORTH (1) in 1947 reported an actinophage active against Streptomyces griseus, several other actinophages active on antibiotic-producing streptomycetes such as S. griseus (2-9), S. aureofaciens (10,11), S. chrysomallus (12), S. mediteranei (13), a streptomyces C1V23-producing novobiocin (14), S. venezuelae (15), and S. erythreus (16) have been reported.…”

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confidence: 99%