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Iu I Kozlova

Publications and source records attributed to Iu I Kozlova.

At least 19 recordsLinked to original sources
PubMed1999

[Actinoplanes brasiliensis INA 3802--a producer of peptide antibiotics].

In the screening programme for new antibiotics an actinomycete culture designated as 3802 was isolated from a soil sample. The culture produced a complex of peptide antibiotics belonging to the group of lantibiotics. The antibiotic complex included gardimycin (actagardin) and new antibiotics of the same group. By the taxonomic properties strain 3802 was classified as Actinoplanes brasiliensis not previously known to produce gardimycin. Conditions of the antibiotic complex biosynthesis by strain 3802, the isolation methods and biological properties were studied.

Actinomycetales↗
PubMed1994

[An anionic polysaccharide from the cell wall of Actinoplanes brasiliensis INA 3802].

The cell wall of Actinoplanes brasiliensis INA 3802 contains a polysaccharide which has an unusual structure. The peculiar structure of the polymer has been established by a nondestructive procedure which included 1H- and 13C-NMR spectroscopy. The polysaccharide consists of six tetrasaccharide links having the following composition -->6(alpha-D-Glc rho-(1-->4)-beta-D-Clc rho 2,3NAcA-(1-->4)-alpha-D-Clc rho 2,3NAc-(1-->4)-beta- D-Man rho 2,3NAcA-(1-->. No structurally identical polymer of the procaryotic cell wall has so far been reported.

Actinomyces↗
PubMed1987

[IR spectrophotometric study of a mixed culture of Streptococcus lactis, strain MSU, and Rhodotorula colostri with agitation of the medium].

Physiological aspects of Streptococcus lactis, strain MSU development in mixed culture with Rhodotorula colostri were studied in connection with nisin biosynthesis. By the IR spectra the average content of the main components in the monoculture cells of S. lactis and its association with the yeast in the stationary growth phase was the following by dry weight: 54-58 per cent of protein, 14-16 per cent of nucleic acids, 26-28 per cent of carbohydrates and 3-5 per cent of lipids. Glucose and nitrogen in the fermentation broth were consumed completely. A significant quantity of KH2PO4 remained in the fermentation broth. Lactic acid excretion was observed. S. lactis, strain MSU was the leading component of the association under the studied cultivation conditions because just its IR spectra dominated in the spectra of the mixed culture.

Lactococcus lactis↗
PubMed1986

[Nisin biosynthesis during the joint cultivation of Streptococcus lactis strain MGU and yeasts].

In simultaneous inoculation of the medium for nisin biosynthesis with Streptococcus lactis (strain MSU) and yeasts such as Rhodotorula colostri, Zigowilliopsis californicus, Hansenuia anomala, Saccharomyces ludvigii, Kluyveromyces lactis and Endomyces magnusi the quantitative ratio of the inoculates in the mixed cultures is not in principle important for the antibiotic synthesis by the Streptococcus. When 6-, 12-, 18- and 24-hour inoculates of the yeasts were added simultaneously to 3-, 6-, 9-, 12- and 18-hour cultures of S. lactis biosynthesis of nisin was at the control level. The fractional composition of the fermentation broth of the above yeast species had no significant effect on biosynthesis of nisin.

Culture Media↗
PubMed1985

[Joint cultivation of Streptococcus lactis, LMU strain, and various species of yeasts].

When S. lactis, strain LMU and yeast were plated out simultaneously on media containing different amounts of amine nitrogen and vitamins, the yeast did not stimulate the synthesis of nisin. Plating out of S. lactis on media with grown cultures of the Rostov baker's yeast, American baker's yeast, Candida guilliermondii, Candida clausenii, Fabospora fragilis, Fabospora macedoniensis, Octosporomyces octosporus, Saccharomyces cerevisiae, races "Ya" and "M" and Saccharomyces globosus resulted in inhibition of the S. lactis growth and nisin synthesis. Cultivation of S. lactis on media with grown cultures of Saccharomyces ludwigii, Hansenula anomala, Kluyveromyces lactis, Endomyces magnusi, Zigowilliopsis californicus, and Rhodotorula colostri resulted in formation of an association providing active growth and development of S. lactis with complete realization of its biosynthetic capacity.

Antibiosis↗
PubMed1984

[Protoplast isolation from a nisin-forming culture of Streptococcus lactis strain MGU].

A procedure for protoplasts of Str. lactis producing nisin was developed. The following lysing factors were used for obtaining the protoplasts: lycozyme, LE enzyme, lysosubtilin and an enzyme isolated from the culture fluid A. levoris. The use of the above factors in different combinations provided an increase in the number of the formed protoplasts from 1-2 in the field of the microscope vision to 15-20, which amounted to 25 per cent of the total number of the cells visible under microscope.

Lactococcus lactis↗
PubMed1982

[Nisin inactivation in a culture of the producer Streptococcus lactis strain MGU].

The intensive biosynthesis of nizin on the glucose-yeast medium is observed during the logarithmic and early lag phases of the staphylococcal growth. The ratio of nizin in the fermentation broth (free nazin) and that bound with the cells depended on pH of the medium. When pH was maintained at 6.6-6.8, the amount of nazin in the cells during and growth logarithmic phase was equal to its amount in the fermentation broth filtrate. During the lag phase marked inactivation of nizin was noted. periodical feeding of casein prevented the nizin inactivation. The preliminary data are indicative of the enzymatic nature of the antibiotic.

Culture Media↗
PubMed1980

[Physiological characteristics of immobilized cells of Streptococcus lactis, Moscow State University strain].

Immobilized cells of Streptococcus lactis, strain MSU, synthesized nisin by 20--30 per cent of the possible maximum antibiotic production level. The immobilized cells of the Streptococcus synthesized nisin by 40--50 per cent probably at the expense of the cell nutrient pools and by 50--60 per cent at the expense of the medium nutrient consumption. The electron microphotographs showed that the cells of Str. lactis, strain MSU, preserved their usual appearance in the granules of polyacrylamide gel 24 hours after immobilization. In 3 weeks there were observed structural changes in the cell wall and inner membranes resulting in the cell lysis after presence in the granules for 3 months.

Bacteriological Techniques↗
PubMed1980

[Method of determining the concentration of the antibiotic nisin].

To accelerate determination of nizin concentrations by the agar-diffusion method it is suggested that Twin-80 be added to the agar. For making the media composition more simple, agarized phosphate buffer, pH 5.0, or agarized water, pH 7.0, is recommended to be used for the lower layer.

Agar↗
PubMed1978

[Nisin formation by immobilized cells of the lactic acid bacterium, Streptococcus lactis].

The problem of microbial cell immobilization at present attracts the ever increasing attention of the scientists, since such organisms may be the source of various enzymes. Production of nizin by the immobilized cells of Str. lactis was studied. It was found that the cells of Str. lactis incorporated into polyacrylamide gel produced nizit on definite media. Still, the amount of the antibiotic was 2-3 times lower than in case of using free cells. The effect of a number of factors on the process of immobilization was studied and the influence of some factors, such as temperature, pH, aeration on nizin synthesis by the immobilized cells of the streptococcus was elucidated. Optimal conditions for nizin biosynthesis by the immobilized cells of Str. lactis were developed.

Acrylamides↗
PubMed1975

[Effect of vitamins on the biosynthesis of nisin by a Streptococcus lactis culture].

Milk is the natural medium for Str. lactis, strain MSU. It is known that in winter and spring the growth and acid production by acidolactic streptococci are decreased. This is due, in particular, to the absence of vitamins in winter and spring milk. A number of vitamins present in complex natural products, such as tomato juice, milk and casein hydrolysates, beaf extract, etc. was studied with respect to their effect on the synthesis of nisin. The organic complexes had a positive effect on the growth of Str. lactis and the antibiotic biosynthesis. However, Str. lactis, strain MSU did not intensify the nisin synthesis on addition of vitamins to the spring skin milk. Possibly, lactis, strain MSU was of low sensitivity to the season of changes in milk.

Animals↗
PubMedDate not supplied

[The carbohydrate-containing cell wall polymers of some species from the cluster "Streptomyces lavendulae"].

The type strains of the cluster "Streptomyces lavendulae" species with a low level of DNA-DNA relatedness were found to contain different cell-wall carbohydrate polymers, whereas the species of this cluster with a level of DNA-DNA relatedness of about 60% contain similar or identical carbohydrate polymers. The type strains Streptomyces katrae VKM Ac-1220T and S. polychromogenes VKM Ac-1207T synthesize mannan with different amounts of alpha-1,2- and alpha-1,3-substituted mannopyranose units and a small number of 1,3-poly(glycerophosphate) chains. The cell walls of S. lavendulocolor VKM Ac-215T and Streptomyces sp. VKM Ac-2117 were found to contain a hitherto unknown teichuronic acid, whose repeating unit is a disaccharide consisting of diaminomannuronic acid and N-acetylgalactosamine:-->4)-beta-D-ManpNAc3NAcA-(1-->3)-alpha-D- GalpNAc-(1-->. In addition, the cell walls of these two streptomycetes contain beta-glucosylated 1,5-poly(ribitol phosphate). The cell walls of S. virginiae VKM Ac-1218T and S. flavotricini VKM Ac-1277T contain the same poly(glucosyl-glycerophosphate). The results presented in this paper are in accordance with the DNA-DNA relatedness data published earlier and indicate a taxonomic significance of the structure of the cell-wall polysaccharides for the delineation of pheneticall/related Streptomyces species.

Cell Wall↗
PubMedDate not supplied

[The cell wall teichoic acids of streptomycetes from the "Streptomyces cyaneus" cluster].

The cell wall anionic polymers of the 13 species of the "Streptomyces cyaneus" cluster have a similar structure and contain beta-glucosylated 1,5-poly(ribitol phosphate) and 1,3-poly(glycerol phosphate). In the degree of glucosylation of the ribitol phosphate units of their teichoic acids, the cluster members can be divided into two groups. The streptomycetes of the first group (S. afghaniensis, S. janthinus, S. purpurascens, S. roseoviolaceus, and S. violatus) are characterized by a very similar structure of their cell walls, completely glucosylated 1,5-poly(ribitol phosphate) chains, and a high degree of DNA homology (67-88%). The cell wall teichoic acids of the second group (S. azureus, S. bellus, S. caelestis, S. coeruleorubidus, S. curacoi, and S. violarus) differ in the degree of beta-glucosylation of their 1,5-poly(ribitol phosphate) chains and have a lower level of DNA homology (54-76%). Two streptomycetes of the cluster (S. cyaneus and S. hawaiiensis) are genetically distant from the other cluster members but have the same composition and structure of the cell wall teichoic acids as the second-group streptomycetes. The data obtained confirm the genetic relatedness of the "S. cyaneus" cluster members and suggest that the structure of the cell wall teichoic acids may serve as one of the taxonomic criteria of the species-level status of streptomycetes.

Cell Wall↗
PubMedDate not supplied

[Joint culturing of Streptococcus lactis, strain MGU with Proteus vulgaris and Bacillus mesentericus].

Nisin synthesis by Streptococcus lactis, strain MGU, grown as a combined culture together with Proteus vulgaris and Bacillus mesentericus under stationary conditions or with stirring does not depend on the quantity of inoculated associated cells. Nisin synthesis in the combined culture drops down by 10-20% at the initial pH 7.5 of the growth medium which is unfavourable for S. lactis producing nisin. The level of nisin biosynthesis does not rise when the pH of the medium is adjusted (either naturally or artificially) to 6.6-6.8 in the presence of glucose and yeast autolysate. S. lactis inhibits the growth of B. mesentericus when grown together with it whereas P. vulgaris inhibits the growth of S. lactis in their combined culture.

Bacillus↗