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I S Kulaev

Publications and source records attributed to I S Kulaev.

At least 19 recordsLinked to original sources
PubMed1992

Identification of a novel secreted glycoprotein of the yeast Saccharomyces cerevisiae stimulated by heat shock.

A new secreted yeast glycoprotein with an Mr of about 400 kDa (gp400) has been found. The glycoprotein is an O-mannosylated oligomer, whose synthesis and export into culture medium are stimulated by heat shock. Intracellular transport of gp400 is carried out by membrane vesicles distinct from the known constitutive secretory vesicles. Immunological analysis revealed gp400 only in Saccharomyces species.

Amino Acids↗
PubMed1991

Isolation, structural and functional characterization of Staphylococcus aureus protoplasts obtained using lysoamidase.

The action of the lysoamidase bacteriolytic complex on Staphylococcus aureus VKM B-209P cells has been studied to obtain protoplasts. The cells in the midlogarithmic phase were the most sensitive to lysoamidase action. It led to local destruction of cell wall due to hydrolysis of the peptidoglycan. Protoplast formation occurred in two steps in the presence of 1 M sucrose. First, osmotically fragile spheroplasts were formed. Then, the protoplasts were released from the destructed cell wall. The protoplast yield was about 80%. The protoplasts preserved the intact ultrastructure and were able to synthesize peptidoglycan fibrillae. Mainly the spheroplasts that maintained the cell-wall residues reversed into bacterial forms. The protoplasts had respiratory activity similar to cells. Respiration of cells and protoplasts was stimulated by various substrates. High rates of oxygen consumption were observed with alpha-glycerophosphate and ethanol as substrates.

Cell Wall↗
PubMed1991

[Localization of acid phosphatase in Saccharomyces cerevisiae and its export into culture media depends on the type of the N-terminal signal peptide].

The aim of this work was to study the character of intracellular distribution and efficiency of yeast acid phosphatase export depending on the type of the N-terminal signal peptide used. A number of plasmids carrying the acid phosphatase genes with different signal peptides sequences was constructed. The main site of the enzyme accumulation for the variant containing its own acid phosphatase signal peptide was the periplasm. Approximately the same pattern was observed when the hybrid signal peptide consisting of acid phosphatase signal peptide and alpha-factor preprosegment tandem was used. Unlike the above-mentioned systems the strain carrying acid phosphatase under the control of alpha factor preprosegment was able to export the enzyme into the culture medium. The experiments have shown the possibility of changing the final localization of secretory proteins by replacing the N-terminal signal peptide.

Acid Phosphatase↗
PubMed1990

[Hydrolysis of a Staphylococcus aureus cell wall peptidoglycan by 209 P lysoamidase].

Hydrolysis of Staphylococcus aureus 209 P cell wall peptidoglycan was accompanied by the liberation of 1.3 mol of C-terminal and 1.2 mol of N-terminal glycine per mole of Glu as well as of 0.5 mol of N-terminal and 0.3 mol of C-terminal alanine. Gel chromatography on Sephadex G-25, ion-exchange chromatography on QAE-Sephadex A-50 and paper electrophoresis of S. aureus peptidoglycan hydrolysates gave seven homogeneous fractions; these fractions were structurally defined. Lysoamidase hydrolyzed bonds Mur-Ala, Gly-Gly and Mur-GlcN in the peptidoglycan molecule. Hydrolysis of glycan chains was accompanied by the formation of large fragments, (GlcN-Mur)9 and (GlcN-Mur)28. The lytic effect of lysoamidase on S. aureus peptidoglycan is coupled with bacteriolytic enzymes of lysoamidase: acetmuramyl amidase, glycyl--glycine endopeptidase and acetyl--muramidase.

Amino Acid Sequence↗
PubMed1979

[Exogenous orthophosphate regulation of ATPase activity of E. coli cells].

The effect of exogenous orthophosphate and mutations in genes, regulating the Pi transport system, on the ATPase activity of E. coli subcellular fractions was studied. It was shown that the orthophosphate starvation resulted in the cessation of the increase in the ATPase activity of membranes and was accompanied by the increase in the analogous activity of a soluble fraction at the expense of the derepression of alkaline phosphatase possessing this activity. The disturbance, resulted from the mutation of protein components participating in the specific binding and transport of orthophosphate, changed the ATPase activity of subcellular fractions: increased the ATPase activity of soluble fraction (independently of the presence of orthophosphate in medium), did not affect significantly the activity of membrane--bound ATPase in the presence of orthophosphate and decreased this activity in the absence of orthophosphate. The data obtained point to the fact that components, binding exogenous orthophosphate and transporting it into a cell, affect the rigidity of the ATPase bound E. coli cytoplasmic membrane. Mutations resulting in the defect in these components relax this bound and lead to the detection of ATPase proper in the periplasm.

Adenosine Triphosphatases↗
PubMed1979

[Interrelationship between metabolic and genetic regulation of alkaline phosphatase and poly- and pyrophosphatases].

The effects of orthophosphate and mutations in the regulatory genes of alkaline phosphatase on the activities of pyrophosphatase and polyphosphatase of E. coli were studied. It was shown that orthophosphate represses the synthesis of alkaline phosphatase as well as that of polyphosphatase without having any effect on pyrophosphatase. The genes phoR and phoS are involved in the formation of a repressory complex both for alkaline phosphatase and polyphosphatase. The gene phoT is probably involved in a partial repression of pyrophosphatase synthesis.

Acid Anhydride Hydrolases↗
PubMed1979

[Possible role of high molecular weight polyphosphates in ATP synthesis from exogenous adenine by the culture of Corynebacterium sp., strain VSTI-301].

An addition of exogenous adenine to an autolysing 72-hour culture of Corynebacterium sp., strain BSTI-301 results in accumulation of as much as 0,6--1,0 mp of ATP per 1 ml of medium. Extracellular ATP accumulation under such conditions is coupled with a considerable decrease of the intracellular content of 5'-phosphoribosyl-1-pyrophosphate, orthophosphate, pyrophosphate and two fractions of high-polymeric polyphosphates PPh3 and PPh4, as compared to the control. The activity of pyrophosphate phosphohydrolase (EC 3.6.1.1) and polyphosphate phosphohydrolase (EC 3.6.1.11) is thereby considerably decreased in the cells growing on exogenous adenine, while the activity of ADP-phosphotransferase (EC 2.7.4.1) is increased 2-fold. It was found that in experiments with 14C-adenine the intracellular content of both ATP and ADP remains unchanged despite a considerable accumulation of extracellular ATP in Corynebacterium sp., strain BSTI-301 cells.

Adenine↗
PubMed1978

Pyrophosphate-stimulated uptake of calcium into the germlings of Phytophthora infestans.

The uptake of 1 micrometer calcium into 6-h-old germination tubes of the fungus Phytophthora infestans follows Michaelis-Menten kinetics with a Km of 33 +/- 4 micrometer and a V of 0.3 nmol.min-1.(5 x 10(4) cells)-1. Uptake is inhibited by ruthenium red and lanthanum (both at 1 micrometer) and by the proton conductors 2,4-dinitrophenol (1 mM) and carbonylcyanide m-chlorophenylhydrazone and carbonylcyanide p-trifluoromethoxyphenylhydrazone (1--10 micrometer) and also by sodium azide. These data suggest that calcium uptake is dependent on energy and on a carrier. Calcium uptake is stimulated by pyrophosphate but not by ATP, orthophosphate, or polyphosphate. This stimulation is prevented by proton conductors or by incubation at 0 degrees C.

Azides↗
PubMed1978

[Effect of mutations in regulatory genes for alkaline phosphatase on the phosphohydrolase spectrum of E. coli periplasm].

The isoform spectra of alkaline and acid phosphatase, pyrophosphataes, and ATPase in periplasm of E. coli were studied using electrophoresis in polyacrylamide gel with subsequent development of zimograms directly in the gel. Wild strains and mutants on 4 regulatory genes of alkaline phosphatase were analyzed. Mutations in regulatory genes were shown to influence the amount of each of the 3 isoforms of alkaline phosphatase and also the spectra of other phosphohydrolases.

Acid Phosphatase↗
PubMed1978

[Interrelationship between metabolic and genetic regulation of alkaline and acid phosphatases in E. coli cells].

The effect of exogenous orthophosphate and mutations in regulatory genes of alkaline phosphatase on the level of nonspecific acid phosphatase was studied. The level of this enzyme as well as the level of alkaline phosphatase were shown to be regulated by exogenous orthophosphate being derepressed under phosphate starvation. The derepression of acid phosphatase is accompanied by more rapid secretion of enzyme from membranes to soluble fraction. Mutations in all the four regulatory genes decrease the level of enzyme in cells. Genes phoR and phoS, participating in regulation of alkaline phosphatase, are required for the derepression of acid phosphatase under the conditions of phosphate starvation.

Acid Phosphatase↗
PubMed1978

[Induction of E. coli alkaline phosphatase synthesis in cells preincubated at low temperatures].

Cell preincubation at lowered t degrees was found to result in increased alcaline phosphatase synthesis. The ability of cells for increased alcaline phosphatase synthesis correlates with increased content of cis-vaccinic acid and higher liquidity of lipids. It has been ascertained that modifications caused by cell preincubation at lowered t degrees favour the greater stability of mRNA coding the alcaline phosphatase.

Alkaline Phosphatase↗
PubMed1977

Energy-dependent transport of manganese into yeast cells and distribution of accumulated ions.

Manganese transport into yeast cells is energy-dependent. It is dependent on endogenous sources of energy and is inhibited by olygomycin (12.5-25 microgramg/ml), 2,4-dinitrophenol (1 mM), 2-deoxyglucose (1-50 mM) and sodium azide (1-10 mM), but is stimulated by cyanide and glucose. The stimulating effect of glucose is eliminated by N-ethylmaleimide and iodoacetate, which apparently inhibit the transport of glucose itself. About 75% of the manganese accumulated in the presence of glucose is found in yeast protoplasts and nearly 25% in the cell walls. A major portion of the accumulated manganese is found in vacuoles. The concentration of osmotically free manganese in the cytosol did not exceed 2 mM, but the concentration in vacuoles was up to 14 mM. The tonoplast is assumed to have a transport system for divalent cations, thereby regulating their concentration in the cytosol.

Azides↗
PubMed1977

[Some pathways of biosynthesis and degradation of polyphosphates from green algae Acetabularia mediterranea].

The activity of ATP: polyphosphate phosphotransferase was detected in free-cellular extracts of Acetabularia mediterranea. The enzyme activity in cells originally deficient in phosphorus and subsequently transferred into the phosphate-containing medium increases 5-10-fold as compared to normal. Polyphosphate degradation in A. mediterranea is probably produced by polyphosphatase, which was also detected in the free-cellular extract. It was shown that the polyphosphatase activity has two pH optima, i.e. 4.5 and 7.5, and is considerably increased when the cells are transferred into the phosphate-free medium. It is assumed that high-molecular polyphosphates involved in A. Mediterranea metabolism are responsible for regulation of orthophosphate and ATP level in the cells by ATP: polyphosphate phosphotransferase and polyphosphatase.

Acetabularia↗
PubMed1977

[Polyphosphate kinase activity in yeast vacuoles].

The enzyme polyphosphate kinase (ATP: Polyphosphate phosphotransferase EC 2.7.4.1) relating to the class of transferases was detected in the vacuoles of Saccharomyces carlsbergensis yeast. The direct ATP: Polyphosphate phosphotransferase reaction resulting in the synthesis of polyphosphates from ATP was shown to occur mainly in vacuoles. The localization of the reverse polyphosphate: ADP phosphatransferase reaction was not established in any of the subcellular yeast fractions studied. The activity of the direct reaction in the yeast protoplasts makes up about 1% of the reverse one, but in vacuoles it is significantly higher and makes up to 19%. Under activation of biochemical processes involved in the production of cell wall components by protoplasts, vacuolar polyphosphates work mainly in the direction of ATP synthesis at the expense of polyphosphates accumulated in vacuoles.

Adenosine Triphosphate↗
PubMed1977

[ On the absence of high-molecular polyphosphates in chloroplasts of Acetabularia mediterranea].

High-molecular polyphosphates have been identified in a crude fraction of chloroplasts of Acetabularia mediterranea. However, after a short-term treatment of the fraction with a hypotonic salt solution and centrifugation in a sucrose density gradient it was found possible to completely separate high-molecular polyphosphates from intact chloroplasts. Consequently the chloroplasts themselves contain no high-molecular polyphosphates. It is assumed that the high-molecular polysphates found in a crude fraction of chloroplasts are constitutents of the "metachromatic" granules which can be revealed in the A. mediterranea cytoplasm by cytochemical methods.

Acetabularia↗
PubMed1976

[Isolation and properties of tripolyphosphatase from Neurospora crassa].

Homogenous preparation of tripolyphosphatase from Neurospora crassa is obtained. The enzyme is found to consist of two equal subunits with molecular weight of 40 000 and to have pH optimum 7.0 and temperature optimum 50 degrees C. Bivalent metal ions are required for its catalytical activity, the hest activators being Co2+, Mg2+ and Mn2+. Strict specificity of the enzyme to tripolyphosphate is demonstrated, Km being 5.9-10(-4) M. The enzyme hydrolyses tripolyphosphate to equimolar mixture of ortho- and pyrophosphate. The enzyme activity depends on orthophosphate and pyrophosphate concentrations in the incubation medium.

Acid Anhydride Hydrolases↗