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T I Orlova

Publications and source records attributed to T I Orlova.

At least 19 recordsLinked to original sources
PubMed2004

[Investigation of cell wall components in actinomycin D resistant Staphylococcus aureus].

Cell walls in 2 strains of Staphylococcus aureus 209P, i.e. actinomycin D susceptible and resistant ones were comparatively investigated. The resistant cells contained much more wall material per a unit of the biomass weight vs the susceptible strain cells, that conformed to thickening of the resistant cell walls detected by electron microscopy and a sharp increase of their electron density. Investigation of peptidoglycans and teichoic acids did not reveal any significant alterations in the structure of the wall components in the actinomycin D resistant cells. Only some increase of glucosamine in the peptidoglycan fraction of the resistant cells vs the susceptible ones was observed. It was shown that preparations of the resistant cell walls and peptidoglycan isolated from the resistant cells were able to bind somewhat lower quantities of actinomycin D vs the analogous preparations of the susceptible cells. The significant decrease of the antibiotic binding by live cells of the resistant strain probably slightly depended on the structure characteristics of the main wall components. The barrier properties of the walls in resistant staphylococci are most likely defined by the wall thickening and consolidation while adapting to actinomycin D.

Cell Wall↗
PubMed2003

[Cell wall components of gramicidin S resistant Staphylococcus aureus].

Comparative study of two staphylococcus aureus 209P strains--resistant and susceptible to gramicidin S demonstrated that peptidoglycanes of two strains differ by ratio glycine/serine at peptide bridges. Besides peptidoglycanes significantly differ by amidation of alfa-carboxyles of glutamic acid in muropeptide. This peptidoglycane modification of resistant cells along with enhanced content of etherized D-alanine in teichoic acid provides lower negative charge of cell wall components. It may influence the cell wall ability to react with positively charged gramicidin molecules. It was shown that isolated cell walls and peptidoglycane of resistant cells binds significantly less gramicidin than cell walls and peptodoglyce of susceptable cells. Simultaneous determination of gramicidin binding by intact S. aureus cells and their killing revealed that lower ability of resistant cells to bind gramicidin is significant but not critical factor of gramicidin resistance.

Anti-Bacterial Agents↗
PubMed2000

[The study of Staphylococcus aureus strain resistant to actinomycin D].

Staphylococcus aureus strains, resistant to actinomycin D (AMD) and to gramicidin S (GS) were selected by S. aureus 209P passing on the media containing the above mentioned drugs. Strain R80 resistant to AMD and strain R9 resistant to GS and AMD and described before didn't perform enzyme inactivation of AMD. Cells of both strains had diminished ability to bind exogenous AMD. Electron microscopy investigation revealed that cells of R80 strain had thickened cell walls and they are characterized by more electron density then cells of R9 strain and of parent strain. Adaption to AMD and GS influenced also on functions of some staphylococcal surface proteins--the activity of endogenous coagulase (clumping factor) was found only in R9 strain. Exogenous coagulase was present in all the strains, but development of resistant to AMD and GS diminished this enzyme activity. It is concluded that development of resistance to AMD and GS causes substantial changes in staphylococcal cell wall, but the type of these changes differ.

Anti-Bacterial Agents↗
PubMed1999

[The capacity of the mycelia of Streptomyces chrysomallus variants to bind exogenous actinomycin D and the synthesis by these variants of macrotetralides].

Streptomyces chrysomallus is known as an organism producing macrotetrolides (MTL) and actinomycin C. The dynamics of the MTL biosynthesis by some variants of S. chrysomallus in the process of their growth in liquid media was studied. In parallel the ability of the culture mycelium (washed or suspended in physiological solution) to bind exogenous actinomycin D (AMD) was estimated. An inverse correlation between the dynamics of MTL biosynthesis and the rate of the AMD binding by the washed mycelium during the whole period of the culture development was observed: a decrease in the culture ability to bind AMD corresponded to active biosynthesis of MTL and an increase in the culture ability to bind AMD corresponded to lower biosynthesis of MTL. It was suggested that the active biosynthesis of MTL correlated not only with a decrease in the ability of the suspended mycelium to bind AMD but also with a decrease in binding of actinomycin synthesized and excreted to the medium by the culture. A decrease in the reflux of the synthesized antibiotic to the cells was likely one of the components of the system of the S. chrysomallus insensitivity to its own antibiotic.

Anti-Bacterial Agents↗
PubMed1997

[Interaction of actinomycin D with suspended mycelium of streptomyces].

Binding of exogenous actinomycin D (AMD) by washed mycelium of streptomycetes i.e. variants of Streptomyces chrysomallus producing and not producing actinomycins and Streptomyces lividans not synthesizing the antibiotics was studied. Dependence of the bound quantity of AMD on its concentration, incubation time and temperature, energy source availability, influence of respiration inhibitors and the membranotropic antibiotic gramicidin S was shown. The intracellularly localized portion of the bound AMD likely penetrated to the cells by diffusion and was strongly bound presumably to DNA in the AMD sensitive S.lividans and to the specific intracellular actinomycin-binding proteins in the AMD resistant variants of S.chrysomallus. The ratio of AMD strongly bound by the mycelium and AMD easily washed with physiological solution and probably localized on the surface was determined. The ratio depended on sensitivity of the culture to AMD and for the variants of S.chrysomallus on the age of the culture and its ability to synthesize actinomycins.

Anti-Bacterial Agents↗
PubMed1996

[Actinomycin D resistance of gramicidin-resistant strains of Staphylococcus].

Factors defining actinomycin D resistance in Staphylococcus aureus resistant to gramicidin S were investigated. The results of the thin layer chromatography, high-voltage electrophoresis and bioautography showed that the resistant cells did not inactivate actinomycin D by the hydrolysis of the lactone bond in the antibiotic molecule. The estimation of the cell ability to bind actinomycin D revealed that the antibiotic binding to the resistant cells was lower by 70-75 per cent as compared to the cells of the susceptible strains. Gramicidin S impaired the intactness of the cytoplasmic membranes and increased the absorption of actinomycin D by the susceptible cells and to a much lesser extent by the cells of the resistant strains. Actinomycin D bound by the susceptible cells could not be washed out with a buffer solution. It could be separated from the cells only by extraction with an organic solvent. Comparative electron microscopy of the susceptible and resistant cells demonstrated that the cell walls in the resistant strains were 1.5-2-fold thicker than the cell walls in the susceptible strains. The actinomycin D resistance of the Staphylococcus strains resistant gramicidin S was likely conditioned by the barrier properties of the morphologically changed cell walls.

Absorption↗
PubMed1996

[Absorption of various actinomycins by Staphylococcus aureus cells].

The absorption of actinomycin D by the cell suspension of Staphylococcus aureus via diffusion linearly depended on the antibiotic concentration in the suspension within the ranges of 2 to 15 micrograms/ml. The absorption of active actinomycins C2, C3 and Au6 was the same as that of actinomycin D. The Staphylococcus intact membranes limited the inlet of the actinomycins to the cells since the membranotropic substances such as gramicidin S and its derivatives and thyrocidin increased their absorption by 30-70 per cent. The absorption of a low active actinomycin D0 and inactive actinomycinic acid even after the exposure to the membranotropic substances was not detectable. These compounds did not form any complexes with DNA. The level of the absorption of the actinomycins by the cells was likely defined by their ability to complex with DNA.

Absorption↗
PubMed1993

[Macrotetrolide antibiotics from a recombinant strain of Streptococcus chrysomallus].

A mixture of antibiotic substances was isolated from the culture fluid of a recombinant strain of Streptomyces chrysomallus. The substances were identified as macrotetrolides (nonactin, monactin, dinactin and trinactin) by the mass spectrometry, ionoform properties and thin layer chromatography in the antibiotic samples and ethylacetate extracts of the fermentation broth filtrate. The parent strain of Streptomyces chrysomallus also synthesized a mixture of macrotetrolides. However, it contained no nonactin and the total level of the macrotetrolide biosynthesis was 5 to 7 time lower than that in the recombinant strain (determined by a chemical method).

Anti-Bacterial Agents↗
PubMed1993

[Metabolism of alpha-ketoacids in erythromycin biosynthesis in various strains of Saccharopolyspora erythraea].

The absence of pyruvate and insignificant levels of alpha-keto-glutarate in the mycelium during the fermentation cycle were characteristic of a highly active erythromycin-producing strain of Saccharopolyspora erythraea. Alpha-keto-glutarate partially excreted to the fermentoffon broth. The activity of pyruvate decarboxylase and alpha-keto-glutarate decarboxylase was detected in the cells during the entire period of the cultivation. The same regularities were observed in the chloramphenicol resistant mutant of the strain. The mycelium of a low productive strain of S.erythraea contained not only alpha-keto-glutarate but also pyruvate and excreted large amounts of keto-acids. By the activity levels of the decarboxylases the low productive strain did not differ from the highly productive one. Propanol did not influence the growth of the low productive strain and the synthesis of erythromycin by it. However, it stimulated accumulation of keto-acids and especially pyruvate in both the mycelium and fermentation broth. Relation between the intensity of keto-acid metabolism and erythromycin biosynthesis is discussed.

Carboxy-Lyases↗
PubMed1991

[Fusion of protoplasts of inactive variants of 2 producers of actinomycin C and the biosynthesis of an antibiotic of non- actinomycin nature].

Fusion of protoplasts of double auxotrophic mutants of spontaneous inactive variants of two cultures producing actinomycin C, i.e. Streptomyces chrysomalus 305 and Streptomyces sp. 26-115 induced by PEG-600 yielded a number of stable recombinants. One of the recombinants requiring proline for its growth was designated as recPro. Unlike its parent strains, it synthesized an antibiotic substance active against gram-positive bacteria and Saccharomyces cerevisiae. The nature of the substance is under investigation.

Anti-Bacterial Agents↗
PubMed1990

[The clinico-epidemiological characteristics of the course of a mixed epidemic of influenza and respiratory syncytial infection in Novoshakhtinsk in the summer of 1986].

In the summer of 1986 the epidemic, whose etiological agents were influenza viruses A (H1N1) and respiratory syncytial virus, was registered among the population of Novoshakhtinsk. In a number of mines 15.3-16.7% of the employees were affected. Influenza viruses A (H1N1) proved to be closely related in their antigenic and biological properties to viruses isolated in the USSR in March-June 1986, as well as to viruses A (H1N1), the etiological agents of the epidemic which developed in the USSR in October-December 1986.

Acute Disease↗
PubMed1989

[Use of Streptomyces sp. 26-115 protoplasts inactivated by heating in fusion experiments].

When heated at 55 degrees C for 30 or 60 minutes protoplasts of auxotrophic mutants of Streptomyces sp. 26-115 producer of actinomycin C (active and inactive variants) lost their capacity for regeneration. The protoplasts heated at at 55 degrees C for 30 minutes and not for 60 minutes maintained some ability to yield recombinants on fusion under the effect of PEG 6000. Unlike the parent active strain, the colonies formed by the spores of the prototrophs yielding on fusion of the intact protoplasts showed wide ranges of antibiotic activity against M. flavus while a significant part of the colonies was inactive. The use of the inactive variant protoplasts heated at 55 degrees C for 30 minutes in the fusion procedure increased the proportion of the inactive variants.

Hot Temperature↗
PubMed1988

[Reduction of actinomycin biosynthesis during protoplast regeneration in an inactive variant producer].

During regeneration of protoplasts in the inactive variant H-2 of the actinomycin-producing organism Streptomyces sp. 26-115 there were detected 1-4 per cent of the colonies synthesizing the antibiotic. The frequency of such colonies (H-2R) did not increase after exposure of the H-2 protoplasts to the fusing agent PEG-1000. The population grown from one colony after three passages on pea agar was sufficiently homogeneous by the antibiotic production property. Variant H-2R was more stable to the effect of streptomycin than the initial variant H-2.

Bacteriological Techniques↗
PubMed1986

[Changes in the permeability of streptomycete cytoplasmic membranes due to gramicidin S and its derivatives].

Exposure of intact mycelium and protoplasts of Streptomyces sp. 26-115 to gramicidin S resulted in impairment of permeability of the cytoplasmic membranes thus inducing a loss of low molecular compounds by the cells and protoplasts. Aminoacyl and guanyl derivatives of gramicidin S with respect to the delta-amine group of ornithine were somewhat less effective with respect to the streptomycete membranes. The same as the initial antibiotic, these derivatives had positively charged groups. The changes in the membranes of the streptomycete protoplasts induced by gramicidin S and its derivatives did not result in the protoplast lysis accompanied by decreasing of the suspension optical density. The neutral derivative having no positive charge and not capable of complexing with the membrane phospholipids and the carboxyl-containing derivative with a negative charge showed a low membrane activity when applied to the protoplasts and induced no impairment of permeability of the intact mycelium membranes. The use of phosphates as factors increasing the membrane activity of the gramicidin derivatives having no positive charge is not possible since in the presence of phosphates streptomycete protoplasts are readily destroyed.

Cell Membrane Permeability↗
PubMed1986

[Isolation and regeneration of the protoplasts of the streptomycete producers of actinomycins C and X].

Protoplasts of S. michiganensis, S. chrysomallus and Streptomyces sp. 26-115, organisms producing actinomycins C and X form in hypertonic salt solution under the action of 3-4,5 mg/ml of lysozyme on the mycelium suspension. For protoplasting, the streptomycetes were grown on the soybean medium in the presence of 0.2-0.8 per cent of glycine. The mycelium of the streptomycete exponential growth phase was more favourable for protoplast formation. Protoplast regeneration was studied on the medium described by Okanishi et al. The quantitative composition of this medium was not optimal for regeneration of protoplasts of the above streptomycetes. The level of their regeneration depended to various extents on concentration of phosphate, magnesium and calcium ions and sucrose in the regeneration medium.

Culture Media↗
PubMed1982

[Comparative biochemical study of 2 natural inactive variants of the actinomycin C producer Actinomyces sp. 26-115 with varying sensitivity to actinomycin].

Two natural variants of the actinomycin C-producing organism Actinomyces sp-26-115, i.e. H1 and H2 differ in their sensitivity to exogenic actinomycin, colony morphology, growth dynamics on the synthetic medium and stability to ultrasound and lysozyme. Both variants synthesize no actinomycin. Variant H1 is sensitive to exogenic actinomycin, while variant H2 is resistant to it. Variants H1 and H2 have some similarity in the composition of membrane proteins. Still, they differ in the protein molecular masses, which are equal to 600000--500000, 220000, 130000. The active variant A and nonactive variant H2 have the most similar compositions of membrane proteins. These variants are also close in their growth dynamics, colony morphology, sensitivity to ultrasound and lysozyme. The membranes of all the variants studied contain phosphatidyl ethanol amide as the main phospholipid component. Insignificant differences are observed only with respect to the minor components. The content of teichoic acids in the cell walls of variant H2 is very high, slightly changes during the developmental stage and insignificantly increases on addition of actinomycin to the medium. The cell wall of variant H1 contains less amounts of teichoic acids. During the developmental stage they are liberated from the wall at a higher rate than peptidoglycan. The sensitivity to actinomycin does not increase with an increase in the culture age. It is probable that teichoic acid of the cell wall is one of the factors providing resistance to actinomycin in variant H2. It may be considered as a barrier preventing transport of exogenic actinomycin into the cell.

Actinomyces↗