The taxonomic investigation of five streptomycete species with synonymous names from the International Streptomyces Project (ISP) collection was carried out using the methods of population analysis, DNA-DNA hybridization, and multilocus DNA fingerprinting. Only two species with synonymous names, S. alboviridis ISP 5326 and S. oligocarbophilus ISP 5589, were found to be actually identical. Three other species investigated, S. krainskii ISP 5321, S. craterifer ISP 5296, and S. anulatus ISP 5361, whose names are usually referred to as synonymous, were shown to be different species.

DNA, Bacterial↗

PubMedDate not supplied

[Review of the systematic position of Actinomyces orientalis (Pittenger et Brigham) Krass. 1970 and its reclassification as Proactinomyces orientalis (Pittenger et Brigham) comb. nov].

The micromorphology, growth cycle, chemical composition of the cell walls, and the susceptibility to lysozyme and specific phages were studied with the culture of Actinomyces orientalis RIA-1074. It is seggested on the basis of these studied to transfer the culture from the Actinomyces genus to the Proactinomyces genus and to rename it Proactinomyces orientalis (Pittinger et Brigham) comb. nov.

Actinomyces↗

PubMedDate not supplied

[The properties of cell wall hydrolysates of Streptococcus group A].

Products obtained from lysis in the cell wall of group A streptococcus have been studied in different growth phases: at the end of the exponential phase and in the stationary one. Endo-beta-N-acetylmuramidase extracted from the culture liquid of Streptomyces levoris 96 has been used for lysis of streptococcus. It is stated that streptococcus cell walls isolated at different growth stages differ in the protein and polysaccharide content. High content of protein in the cell wall of a young culture makes lower the initial rate of the walls' hydrolysis by endo-beta-N-acetylmuramidase. However, with the enzyme penetration into peptidoglycan the rate of hydrolysis of cell walls gets higher and after four-hour incubation the lysis degree of walls of the 16- and 8-hour cultures reaches the equal value (63%). Studies in the protein composition of lysates of the streptococcus cell walls have shown that they contain at least 12 proteins most of which are acid and neutral ones.

Cell Wall↗

PubMedDate not supplied

[Search for A factor-dependent variants in actinomycete population].

A study of 28 nocardia-like, asporogenous, and oligosporous spontaneous morphological variants belonging to 23 species of streptomycetes revealed five strains producing regulators of the A-factor group. Streptomyces griseus 1439, which forms aerial mycelium and spores only in the presence of exogenous A-factor was used as the test strain. Among the 28 spontaneous variants, three new A-factor-dependent strains were revealed, which represented the species Streptomyces griseus, S. citreofluorescens, and S. viridovulgaris subsp. albomarinus. These weakly differentiated variants id not produce A-factor and behaved as its recipients, responding by changes in their morphological characteristics at a concentration of this regulator in the medium of 0.01 microgram/ml and higher. The original collection strains in whose populations the variants were selected produced substances of the A-factor group. The A-factor-dependent variants differed in the level of the regulator required for maximal expression of the morphological characteristics were shown: it was necessary to introduce the A-factor at a concentration of 1 microgram/ml for S. citreofluorescens and S. viridovulgaris subsp. albomarinus and at 10 micrograms/ml for S. griseus.

4-Butyrolactone↗

PubMedDate not supplied

[Endospore formation by Streptomyces avermitilis in submerged culture].

The capability of streptomycetes to form endospores during their life cycle was studied in submerged cultures of Streptomyces avermitilis. Submerged S. avermitilis spores were most intensely formed (1) during the culture development cycles on synthetic medium CP1 with glucose under phosphate limitation, and (2) in autolysing cell suspensions of high density obtained by tenfold concentration of a stationary-phase culture grown in a synthetic medium resuspended in phosphate buffer (pH 7.2) with 0.2% CaCl2. Endospores of S. avermitilis formed in submerged cultures shared the major characteristics of specialized microbial resting forms: heat resistance, resistance to lysozyme, ability to pertain to the main species-defining features, and ultrastructural organization characteristic of endospores. They can be considered a resting form of streptomycetes alternative to the spores formed exogenously on aerial mycelium in a surface culture.

Culture Media↗

PubMedDate not supplied

[Use of the electron paramagnetic resonance method for the comparative evaluation of the effectiveness of the protective media used in the lyophilization of actimomycetes].

The accumulation of free radicals correlates with an increase in the percentage of killed lyophilized spores of actinomycetes. Therefore, the EPR method in combination with the method of "accelerated storage" at 37 degrees C was used to evaluate rapidly (during one month) the effectiveness and to select certain protective media for stabilization of actinomycetes cultures. The EPR method can be applied for comparative evaluation of only those media which did not contain originally free radicals.

Cryoprotective Agents↗

PubMedDate not supplied

[Analysis of genomic similarity in Streptomycetes belonging to the fluorescent subgroup as a confirmation of their taxonomic revision using a population method].

Genomic similarity was analysed in streptomycetes belonging to the fluorescent subgroup: Streptomyces chrysomallus, S. fluorescens, S. galbofluorescens and S. citreofluorescens. The degree of reference S. chrysomalius DNA hybridization with S. fluorescens and S. galbofluorescens DNAs was 75 and 82%, respectively, thus being within the limits of the intraspecial hybridization level. S. citreofluorescens DNA showed a 55% homology with reference S. chrysomallus DNA, which corresponded to the range of interspecies hybridization. These conclusions were confirmed by the results obtained in analysing the thermostability of hybrid duplexes. Therefore, these findings are consistent with the data of revising the species taxonomy of this streptomycetes subgroup which was done using the method of comparative population analysis. The population model proposed by one of the authors can be used to assess the intraspecies level of DNA-DNA hybridization.

Base Sequence↗

PubMedDate not supplied

[Lytic activity of Streptomyces levoris in relation to different bacterial groups].

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Acetylglucosaminidase↗