The effect of lovastatin, a competing inhibitor of 3-hydroxy-3-methylglutaryl-CoA-reductase (HMG-CoA-reductase) of the fungal origin on the growth of and ergosterol biosynthesis by Rh. rubra VKPM Y 1337 was studied. It was shown that the yeast growth was inhibited by lovastatin in concentrations of 0.25 to 5.0 micrograms/ml when the inhibitor was added to the cultivation medium either with the inoculum or at later periods of the yeast cultivation. In concentrations of 2.0 to 5.0 micrograms/ml lovastatin almost completely inhibited the yeast growth. In the concentrations tested the inhibitor did not decrease the ergosterol level in the yeast cells below 40 per cent of the control. When lovastatin was added in concentrations of 1.0 to 5.0 micrograms/ml the maximum inhibition of the ergosterol biosynthesis was observed at the end of the growth log phase. Further cultivation of the yeast in the presence of the inhibitor resulted in an increase of the ergosterol biosynthesis. It is believed that the increase in the quantity of ergosterol may be due either to the HMG-CoA-reductase induction under the action of the inhibitor or to its inactivation as a result of the hydroxylation.

Anticholesteremic Agents↗

PubMed1995

[Data on the cultural and morphologic features of dissociation forms of nisin-producing Streptococcus].

Colonies and cells of S and G variants of Streptococcus lactis, strain MSU were studied comparatively. It was shown that in the G form the growth rate and other biosynthetic peculiarities and in particular the capacity for the nisin synthesis were lower. Morphological properties of the colonies and cells of the S and G variants of the nisin-producing streptococcus were investigated.

Cell Division↗

PubMed1995

[Action of lovastatin--an inhibitor of cholesterol biosynthesis on bacterial bioluminescence].

The action of lovastatin, a competing inhibitor of 3-hydroxy-3-methylglutaryl CoA reductase, on bacterial bioluminescence was studied. The lovastatin lactone form and sodium salt of mevinolinic acid inhibited bacterial luciferase in vitro but did not affect bioluminescence of the intact cells of the luminous bacteria. The inhibition was found to be of a competing character in regard to aliphatic aldehyde, the bacterial luciferase substrate. Conditions under which the bioluminescence inhibition was proportional to the lovastatin concentration in the incubation mixture and a bioluminescence method for quantitative determination of the inhibitor were developed.

Anticholesteremic Agents↗

PubMed1992

[The effect of physicochemical environmental factors on the growth of gram-positive bacterial dissociants].

The growth of R-, S- and M (g)-dissociants of Streptococcus lactis, Bacillus coagulans, Rhodococcus rubropertinctus under the action of some physico-chemical factors: temperature, pH, ultraviolet (UV) rays, high concentration of NaCl and storage have been compared. R-variants gain selective advantage under the influence of UV-irradiation, high temperature and storage; S-variants--at decreasing of active pH of medium; M (g)-variants--at decreasing of growth temperature, high values of pH, increased NaCl concentration. The dissociation has been concluded to enlarge the limits of the species survival.

Bacillus↗

PubMed1992

[Calcium transport in cells of Streptomyces chrysomallus var. macrotetrolidi-- a producer of macrotetrolide antibiotics].

The dynamics of calcium accumulation by cells in batch cultures and by washed cells was defined with a radiotracer procedure for Streptomyces chrysomallus var. macrotetrolidi producing ionophore macrotetrolide antibiotics. It was shown that macrotetrolides added to the cultivation medium could regulate intracellular contents of calcium by participating in cation transport. Moreover, possible functioning of a Ca-ATPase system for the calcium active transport in the streptomycete cells was demonstrated.

Anti-Bacterial Agents↗

PubMed1992

[Isolation of nisin from native solution and its purification on cationites].

It was found possible to use organic sorbents and in particular carboxylic cationites for isolation of nisin from the fermentation broth filtrate and its purification. Nisin is known as a polypeptide antibiotic applied as a preservative. The sorbents were shown to have high exchange capacities by the isolated substance and mechanical strength and resistance. They also proved to be highly stable.

Adsorption↗

PubMed1991

[The separation of true coagulases from other enzymes of the extracellular proteolytic complex of Aspergillus ochraceus by using affinity chromatography].

A complex of proteases has been isolated from the cultural broth of fungi Aspergillus ochraceus HP-19 by precipitation ammonium sulfate. Using the method of affinity chromatography on the biospecific sorbents the conditions for separation of proteases into ones with coagulase activity and with fibrinolytic activity have been found.

Aspergillus ochraceus↗

PubMed1991

[Antibiotic activity of marine gram-negative bacteria].

An antimicrobial substance was isolated from the culture fluid of Vibrio fischeri belonging to ++gram-negative sea bacteria. The substance was shown to be highly active against ++gram-positive cocci and less active against some other ++gram-positive bacteria and fungi. The active substance was defined as a low molecular weight compound which appeared to be thermostable and had positive ninhydrin reaction. The antibiotic formed when the culture was grown in the media containing sea water and protein hydrolysates or yeast extract during the exponential phase. The maximum antibiotic activity was observed during the stationary phase of culture development.

Anti-Bacterial Agents↗

PubMed1990

[Study of nisin, a polypeptide antibiotic produced by a culture of Streptococcus lactis, strain MSU].

The drug nisin produced by the lactic acid bacteria S. lactis, strain MSU, was identified and described. After 18-hour cultivation of the strain the fermentation broth was centrifuged. The centrifugate contained at an average 2000 IU/ml of the antibiotic. It was purified on silica gel C-3, the eluate was lyophilized and the dry substance was studied by disk electrophoresis in 20 per cent PAAG in the presence of sodium dodecylsulfate. It was found that S. lactis, strain MSU, produced a polypeptide component of the molecular weight of 7000 D. Its electrophoretic mobility corresponded to that of nisaplin. Therefore, nisin was shown to be identical to nisaplin.

Anti-Bacterial Agents↗

PubMed1990

[Thiol-dependent serine proteinase from Streptomyces thermovulgaris].

The cultural filtrates of S. thermovulgaris contain a proteinase which is active towards the chromogenic subtilisin substrate, Z-Ala-Ala-Leu-pNa, and azocasein. Pure enzyme preparations were obtained by affinity chromatography on bacitracin-Sepharose with subsequent rechromatography on the same adsorbent. The proteinase was completely inactivated by PMSF and DFP, the specific inhibitors for serine proteinase, by thiol reagents (HgCl2, PCMB) and by the protein inhibitor from S. jantinus. The pH activity optimum for the enzyme is 7.8-8.2, temperature optimum is 55 degrees C. The enzyme is stable at pH 6-9, has a pI of 5.0 and a molecular mass of 32 kDa. When tested against the peptide substrate, the enzyme shows a specificity characteristic for subtilisins. The N-terminal sequence of the enzyme, Tyr-Thr-Pro-Asn-Asp-Pro-Tyr-Phe-Ser-Ser-Arg-Gln-Tyr-Gly, shows a 100% homology with that of terminase, a thiol-dependent serine proteinase. On the basis of the above considerations the enzyme may be related to the subfamily of thiol-dependent serine proteinases.

Amino Acid Sequence↗

PubMed1989

[The role of bitoxibacillin components in the manifestation of its biological activity].

New methods were developed and applied to quantitative determination of beta-exotoxin and antibiotic activity of delta-endotoxin with respect to Micrococcus spp. in bitoxibacillin (BTB) and the fermentation broths prepared under industrial conditions. The biosynthesis of beta-exotoxin in the period of its maximum accumulation during the fermentation was estimated. It was shown that the primary biological effect of BTB on insects consisted in the actions of beta-exotoxin and delta-endotoxin. Biological activity of each of the entomocidal components of the entomocidal components of BTB did not practically correlated with the number of viable spores. There was a correlation between the antibiotic activity of crystalline B. thuringiensis subsp. thuringiensis solutions and the insecticidal activity of the entomopathogenic preparations. Determination of beta-exotoxin and antibiotic activity of delta-endotoxin might be used as a complex procedure for testing the quality of BTB. The method for estimating antibiotic activity of the crystal solutions allowed one to assay the biological activity of other preparations based on Bacillus thuringiensis non-synthesizing beta-exotoxin.

Animals↗

PubMed1989

[Isolation and properties of macrotetrolide synthase from the mycelium of Actinomycetes].

The formation of cyclic polyester antibiotics (macrotetrolides) from nactinic acids in a cell-free system in the presence of a mycelium homogenate of Streptomyces chryzomallus var. macrotetrolidi, a producer of a complex of homologous macrotetrolide antibiotics, was demonstrated. An enzyme catalyzing the formation of an ester macrotetrolide ring and possessing a specific activity of 360 mumol/min/mg of protein has been isolated for the first time from the mycelium homogenate and purified 176-fold with a 18% yield. Macrotetrolide synthase represents a macromolecular complex with a molecular mass of 360 kDa formed by several heterogeneous polypeptides. The effects of physico-chemical environmental factors on the stability and activity of the enzyme were demonstrated. The optimal conditions for the manifestation of the synthase activity (10 mM Tris-HCl, pH 8.0, 10% ethanol, 2% glycerol, 200 micrograms/ml of nactinic acids) were selected. The kinetic parameters of the enzyme-catalyzed macrotetrolide synthesis reaction (Km = 2.9.10(-4) M, V = 22.3 microM/min) were determined.

Anti-Bacterial Agents↗

PubMed1989

[Composition and immunological activity of membrane-bound surface glycoprotein from Crithidia oncopelti].

A membrane-bound glycoprotein with a molecular weight of 10000-12000 was isolated from Crithidia oncopelti and purified. The glycoprotein contained peptide, carbohydrate and lipid fragments and phosphorus. The peptide fragment was represented by 10 amino acids. The carbohydrate fragment was represented by 7 monosaccharides. The lipid part was mainly represented by stearic acid. The glycoprotein showed immunostimulating properties. It had a comitogenic effect on murine spleen cells in vitro and induced tumoricidal activity in murine peritoneal macrophages in vitro and in vivo.

Adjuvants, Immunologic↗