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Biomedical subjects

V D Gruzina

Publications and source records attributed to V D Gruzina.

7 recordsLinked to original sources
PubMed2003

[A-Factor as a selective agent for isolation of the soil Gram-negative bacterium strain--the producent of an antibacterial antibiotic].

It was shown the stimulating role of A-factor on soil prokaryotes growth. Soil sample culturing on agar medium, containing A-factor, resulted in the colony forming units (CFU) increasing in comparison with culturing on the medium without this regulator. Gram-negative bacteria were the reason of CFU increasing; previously the effect of A-factor on bacteria of this group was not shown. Gram-negative rod bacterial strain No. 35 was isolated and shown that CFU number was approximately twice increased at A-factor concentration in agar medium 2 and 7 mcg/ml; high A-factor concentration up to 28 mcg/ml was not effective. Isolated strain No. 35 is the producer of antibiotic, effective against gram-positive bacteria.

4-Butyrolactone↗
PubMed1991

[Selection of the optimal conditions for the procurement and regeneration of protoplasts of the industrial strain of Streptomyces rimosus, the producer of oxytetracycline, and the effect of the protoplasting process on the antibiotic activity].

Optimal conditions for protoplasting of the Streptomyces rimosus industrial strain No. 1 producing oxytetracycline were developed. Observation of the early stages of the protoplast regeneration in microchambers showed that there were two regeneration types: normal and anomalous. The latter was likely defined by the glycine effect on cell wall synthesis. It was accompanied by the stage in which the protoplasts had the form of multiplying protoplast-like cells. The protoplasting of the S. rimosus culture producing oxytetracycline resulted in an increase in the variability of an antibiotic producing property and the frequency of low active variants.

Bacteriological Techniques↗
PubMed1983

[Antibiotic formation in N-nitrosomethylbiuret exposure at different stages of conidium initiation in Penicillium chrysogenum, a producer of penicillin].

Survival and variation of strain 9741 of P. chrysogenum treated with N-nitroso-N-methyl biuret (NMB) at various stages of conidia initiation were studied. It was shown that the interval between the minimum and maximum levels of the conidia sensitivity to NMB was equal to 80 minutes, which corresponded to the period of DNA replication in the culture. When preliminary incubated conidia were subjected to the treatment, the frequency of the variants with higher potency increased as compared to the treatment of air-dried conidia. The variation coefficient increased, when conidia were treated with the mutagen after preliminary incubation for 80 or 100 minutes. This may be used for increasing the efficacy of directed improvement of the culture.

Genetic Variation↗
PubMed1981

[Exclusion of propyl alcohol from the medium for culturing the erythromycin producer].

Propyl alcohol is a precursor of erythromycin. It is one of the components of the medium for production of the antibiotic. Still, this raw material has an unfavorable effect on employees and is fire hazardous. The results of the development of the erythromycin-producing organism are presented. A strain requiring no propyl alcohol as a precursor in the medium and producing the same amounts of the antibiotic was obtained by means of step-wise selection with the use of a mutagen.

1-Propanol↗
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

[A new regulatory function of the A-factor--stimulation of the streptomyces spore germination].

Spore germination in streptomycetes was shown to be stimulated by exogenously added A-factor. Agar medium either containing or not containing A-factor was inoculated with spore suspensions of three strains differing in their ability to produce regulators of the A-factor group: Streptomyces griseus 773, which produces A-factor and two its lower homologs, S. coelicolor A3(2), which forms six AcL-factors (A-factor analogues), and S. avermitilis JCM5070, which fails to form regulators of this group. The count of the grown colonies showed that exogenous A-factor stimulated spore germination in strains that were themselves able to synthesize regulators of the A-factor group. In S. griseus 773, the number of germinated spores increased by 67% on average after the addition A-factor to the medium in an amount 10 micrograms/ml. In strain S. coelicolor A3 (2), the number of germinated spores increased by 75% after the addition of 1 microgram/ml of A-factor. During germination of the S. avermitilis JCM5070 spores, no changes in the CFU number was observed after the addition of A-factor.

4-Butyrolactone↗