Search PubMed⌕ Search

Biomedical subjects

V D Kuznetsov

Publications and source records attributed to V D Kuznetsov.

122 records · Page 7Linked to original sources
PubMedDate not supplied

[Systematic position of an autotrophic actinomycete isolated from a floodplain marsh near Moscow].

A hydrogen-oxidizing actinomycete (Z-1046) was isolated from a flood-plain marsh in the Moscow Region. Its taxonomy was compared with that of similar cultures belonging to international special standards of actinomycetes (ISP). The strain Z-1046 was found to be identical with Streptomyces autotrophicus ISP-5011 (RIA-1008, ATCC-19727, CBS-466.68, IFO-12743). It has been also shown that the generic identification of the standard culture ISP-5011 is erroneous: as Hirsch (1960) holds, the culture belongs to the genus of Nocardia (Proactinomyces). Thus, the culture Streptomyces (Actinomyces) autotrophicus ISP-5011 must be eliminated from the international special standards of the genera Streptomyces and Streptoverticillium. The autotrophous actinomycete that we have isolated is classed as Proactinomyces autotrophicus comb. nov. (=Streptomyces autotrophicus Takamiya et Tubaki, 1956, ISP-5011, RIA-1008, ATCC-19727, CBS-466.68, IFO-12743, =Nocardia autotrophica, Hirsch, 1960).

Actinomycetales↗
PubMedDate not supplied

[Fatty acid composition of the lipids of streptomycetes and their nocardia-like mutants].

The models "population--Nocardia-like spontaneous mutants" for 14 cultures of Streptomycetes and Streptoverticillium were used to assess the fatty acid composition of lipids as a criterion for generic differentiation of Streptomyces and Nocardia cultures. The composition of fatty acids in the Nocardia-like mutant Str. kanamyceticus RIA-771 was found to be identical with that of Nocardia asteroides RIA-43 and Nocardia brasiliensis RIA-440, i. e. generic chemotaxonomic traits "overlapped" in the process of spontaneous intraspecial variability. In different strains of one and the same species as well as in five different species, the quantitative composition of fatty acids either hardly changed in the process of intraspecial variability or the ratio between fatty acids changed, so that Nocardia-like mutants resembled typical cultures of the Nocardia genus in this characteristics. The results suggest that the quantitative composition of fatty acids of lipids cannot be regarded as a sufficiently reliable criterion for generic differentiation of Steptomyces and Nocardia cultures. This trait should be used only for additional characterization of cultures.

Chemical Phenomena↗
PubMedDate not supplied

[Systematic place of the act nomycetes of the Albidus Krassilnikov, 1970 group].

Detailed studies of the taxonomical characteristics and the complex of produced antibiotics made it possible to establish the identity of Actinomyces albus var. fungatus, Solovieva et Rudaya, 1959 and Actinomyces tumemacerans, Krassilnikov et Koveshnikov, 1962. Both organisms produce a complex of antibiotics comprising albofungin, albonursin, and a polyene antibiotic belonging to the group of tetraenes. The cultures do not belong to the group of verticillate actinomycetes as was believed earlier (Krassilnikov, 1970). The later name, Actinomyces tumemacerans, is more appropriate since the organism described under the name of Act. albus var. fungatus differs sharply from other representatives of Act. albus and therefore cannot be regarded as its variety (nomen confusum). Actinomyces sp. RIA-248 producing albofungin differs from Act. tumemacerans P-42 as well as from Act. albus var. fungatus RIA-247 by the complex of produced antibiotics and other taxonomic properties. Apparently, it should be classed as a new species.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Endo-N-acetylglucosaminidase formed by Streptomyces levoris].

Endo-N-acetylglucoseaminidase (EC 3.2.1.30) was prepared from the cultural broth of Streptomyces levoris 96 using precipitation with ammonium sulfate, gel filtration on Sephadex G-25 and ion exchange chromatography on DEAE-cellulose. The isoelectric point of the enzyme is 4.2 Str. levoris produces various quantities of the enzyme depending on the composition of the growth medium. A medium in which the enzyme is produced in maximal amounts has been selected. The effect of peptidoglycan, cell walls and chitin added to the medium on the enzyme biosynthesis was studied. Chitin induced biosynthesis of the enzyme by 35--45%.

Acetylglucosaminidase↗
PubMedDate not supplied

[Comparative study of methods for isolating glucose isomerase from Streptomyces albogriseolus mycelium].

Different procedures for disintegrating the biomass of Streptomyces albogriseolus were compared, and the recovery of glucose isomerase was analysed for each of the procedures. The following techniques were tested: disintegration of the mycelium with ultrasound and with pressure, autolysis in the presence of lysozyme and in its absence. The yields of the enzyme and total protein were found to depend on the time during which the biomass was treated. The effect of different procedures for isolating the enzyme on its recovery and activity is discussed.

Aldose-Ketose Isomerases↗
PubMedDate not supplied

[Population composition of Actinomyces tumemacerans and Actinomyces albus var. fungatus].

The population analysis of Actinomyces tumemacerans and Actinomyces albus var. fungatus has revealed identical homologous series of spontaneous variants, this suggesting the genetical relationship of the cultures. Variants of the same type (basic, oligosporous, asporogenous and proactinomycete-like) are identical not only according to their individual properties (Kuznetsov, 1973) but also in total characteristics typical of the variants of a given species. Populations of the studied cultures comprise variants synthesizing several antibiotics, i.e. albofungin, albonursin and tetraene (basic and oligosporous variants), albofungin and tetraene (asprogenous green variants), as well as variants producing only one tetraene antibiotic (proactinomycete-like variants). Therefore, the population analysis based on the law of homologous series in hereditary variability of actinomycetes can be used as a new approach to the taxonomy of these microorganisms.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Clarifying the systematic position of Actinomyces erythraeus Waksman et Curtis 1916 and its transfer to the genus Proactinomyces].

Cell walls of Actinomyces erythraeus RIA-1387 were found to contain m-diaminopimelic acid, arabinose, and galactose (type IV of cell walls). The mycelium undergoes fragmentation during superficial and submerged growth, and is not susceptible, or only mildly sensitive, to the action of lysozyme. The colonies of Act. erythraeus have no horizontal layers. These data suggest that the organism was erroneously classed as belonging to the Actinomyces genus. It should be transferred to the Proactinomyces genus under the name of Proactinomyces erythraeus (Waksman et Curtis) comb. nov.

Carbohydrates↗
PubMedDate not supplied

[Hydrolyzing ability of yeast proteases in relation to protein substrates].

The possibility of use of brewer's yeast as multienzymatic preparations for hydrolyzing of animal blood proteins was demonstrated. The kinetic characteristics of hydrolysis of blood proteins by activated brewer's yeast mass and neutral proteinase from Bacillus subtilis 102 and the activation energies were estimated. Brewer's yeast biomass may be used as a source of enzymes of broad substrate specificity and noncontiguous amino acids, in particular, isoleucine, to increase the biological efficiency of blood proteins by 15-30%.

Animals↗
PubMedDate not supplied

[Prognosing the viability of lyophilized Actinomyces parvullus spores based on the "accelerated storage" method].

A technique of "accelerated storage" was used to evaluate promptly the effectiveness of protective (suspension) media for lyophilization and further storage of spores of Actinomyces parvullus 99. The number of survived spores can be predicted using the Arrhenius diagram and the van't Hoff rule. Equine serum without a conserving agent was found to be the most effective protective medium for lyophilizing spores of Act. parvullus, as compared to such media as milk containing no fat or a mixture of 3 per cent solutions of gelatin and glucose.

Freeze Drying↗
PubMedDate not supplied

[Chitinase formation by actinomycetes in deep cultures].

Actinomycetes were cultivated in the medium containing demineralized crab shells as a source of carbon. Chitinase was found in filtrates of the cultural broth of all 44 studied strains. The activity of the extracellular chitinase was determined both by decomposition of ground chitin (CHI-activity) and colloid chitin (CHI-activity). The ratio between CHI and CHX in filtrates of the cultural broth of the most active nine strains varied from one to two.

Actinomycetales↗
PubMedDate not supplied

[Lytic enzymes produced by Actinomyces levoris].

The composition of the enzyme complex produced by Actinomyces levoris which exhibits lytic action on the cell walls of Streptococcus lactis was studied by gel filtration on Sephadex G-25, ion exchange chromatography and isoelectric focusing. The complex was found to contain at least seven enzymes having different isoelectric points and substrate specificity. The enzymes were divided into three groups. (1) The enzyme with pI 10.2 seems to be a specific glucosidase; it possesses a high activity of the cell wall lysis and lacks a proteolytic activity. (2) The enzymes with pI 9.2 and 9.0 are, apparently, specific lytic proteases; they display both lytic and proteolytic activities. (3) The enzymes with pI 10.0, 9.5, 5.7 and 4.2 are, presumably, non-specific lytic proteases; they have a low lytic activity and a high proteolytic activity.

Bacteriolysis↗