Search PubMed⌕ Search

Biomedical subjects

G K Degteva

Publications and source records attributed to G K Degteva.

At least 37 records · Page 2Linked to original sources
PubMed1983

[Characteristics of the composition of higher fatty acids in methicillin-resistant and methicillin-sensitive Staphylococci].

The composition of fatty acids of methicillin-resistant (MR) and methicillin-sensitive (MS) strains of Staph. aureus and Staph. epidermidis was determined with the method of reactive gas liquid chromatography. The MS staphylococci of the above species differed by the content of acids with branched chains of iso- and anteisostructures and straight chains. Anteisoacids in the cells of Staph. epidermidis amounted almost to 80 per cent of the total number of the acids, while in the cells of Staph. aureus, their total number amounted only to a half of the fatty acid pool. Comparison of the composition of the fatty acids of the MS and MR strains of Staph. aureus revealed differences in the proportions of the anteiso- and isoacids. The total number of the long-chain C20.0 acid in the cells of Staph. epidermidis resistant to methicillin was lower as compared to that in the sensitive cells.

Chromatography, Gas↗
PubMed1982

[Characteristics of the protein spectra of methicillin-resistant and methicillin-sensitive staphylococcal strains].

Differences in the protein-composition of methicillin resistant (MR) and methicillin sensitive (MS) staphylococci were shown by means of disk electrophoresis. Extracellular proteins of MR and MS staphylococci were studied electrophoretically. The study revealed no relation between the culture grouping by the protein spectra and resistance to methicillin. Comparison of the spectra of soluble intracellular proteins showed a certain correlation with methicillin resistance.

Bacterial Proteins↗
PubMed1982

[Interaction of NADH-dehydrogenase from M. lysodeikticus membranes with lipids in a reconstituted system].

The NADH-dehydrogenase isolated from the M. lysodeikticus membranes was reconstituted into liposomes from the lipids obtained from the same membranes. The presence and degree of the reconstitution were investigated by two-dimensional immunoelectrophoresis and photoreactive hydrophobic label. The quenching of protein fluorescence by the aqueous quencher J- was practically the same for the enzyme in the reconstituted system and in the detergent solution, whereas the quencher interacting with the membrane--cetylpyridinium chloride--was effective in the first case and not effective in the second one. Evidence for the energy transfer from protein chromophores of NADH dehydrogenase in the proteoliposomes (lambda excit = 286 nm) to the hydrophobic fluorescent probe pyrene was obtained. It was found that about 30% of the chromophores in the enzyme molecule are involved in this process. The hydrophobic spin probe, whose paramagnetic fragment is located on the surface and not inside the hydrophobic phase of the membrane, can act as electron acceptor during NADH oxidation in the reconstituted system. The data obtained are suggestive of the exposure of the bulk of the enzyme molecule to the environment and of interaction of the smaller part of the molecule with the lipid phase. The active center is located on the part of the enzyme molecule which is exposed to water. It is assumed that the NADH-dehydrogenase molecule is exposed to water. It is assumed that the NADH-dehydrogenase molecule is involved in heat diffusion which facilitates the active center interaction with the membrane surface.

Cell Membrane↗
PubMed1979

[Membrane protein spectra of staphylococci from a comparative physiological aspect].

Membrane protein spectra, obtained by electrophoresis in the system polyacrylamide gel--sodium dodecysolfate, were studied in 14 staphylococcal strains with different properties. The proteinograms of membranes were shown to be useful as an additional criterion in the identification of staphylococci. Fractions and their combination characteristic of all the strains and their separate groups were revealed in the protein spectra of staphylococcal membranes.

Bacterial Proteins↗
PubMed1979

[Quantitative indices of the activity and the electrophoretic characteristics of staphylococcal catalase].

The average levels of activity of intracellular and extracellular catalase were determined. The activity of intracellular catalase was shown to be significantly higher than that of extracellular catalase, the average level of activity of extracellular catalase being higher in S. aureus than in S. epidermidis. In most of the strains one zone of extracellular catalase and two molecular forms of intracellular catalase were revealed by means of polyacrylamide gel electrophoresis.

Catalase↗
PubMed1979

[Study of membrane proteins from Microccus lysodeikticus using immunochemical methods].

Using immunoelectrophoresis, the antigenicity of various protein fractions of the Micrococcus lysodeikticus membranes was evaluated. It was shown that both the peripheral and integral membrane proteins possess the antigenic determinants. The antiserum exhausted by the M. lysodeikticus mebranes loses its ability to interact with intergral proteins, which are not solubilized by Triton X-100. It was thus assumed that the integral proteins are exposed on the membrane surface constantly or periodically and that there exist no proteins which are completely and permanently incorporated into the lipid bilayer. The respiratory chain of the M. lysodeikticus membrane is inhibited by membrane immunoglobulins by 50%. This is probably due to the presence in the membrane antiserum of antibodies specific to the respiratory chain enzymes. Evidence for this assumption can be derived from the fact that partially purified cytochrome b556 forms a precipitation zone with the membrane antiserum and that the activity of membrane NADH-dehydrogenase is inhibited by a monoserum against NADH-dehydrogenase.

Cell Membrane↗
PubMed1975

[Comparison of the protein spectra of typical and atypical mycobacteria using the disc electrophoresis method in polyacrylamide gel].

Protein spectra of 19 strains of typical and atypical mycobacteria were studied. The advantage of protein extracts obtained from the living cells destroyed by press was shown in experiments of fractionation in polyacrylamide gel. On the basis of similarity indices of the protein spectra a conditioned scheme reflecting the extent of similarity of the cultures under study was drawn. there were revealed protein fractions common for the majority of the cultures studied; It was impossible to isolate the fractions strictly specific of individual groups.

Bacterial Proteins↗
PubMedDate not supplied

[Isolation and properties of an extracellular proteinase of Staphylococcus aureus].

Serine proteinase splitting the peptide bonds which are formed by carboxyl groups of dicarboxylic amino acids was isolated from the supernatant of the Staphylococcus aureus culture liquid. It is similar to the enzyme isolated by Drapeau from Staphylococcus aureus strain V8 in its specifidity, molecular weight, amino acid composition, existence of two pH optima (pH 4.6 and 8.2). But there are some differences between the two proteinase in the content of dicarbonic amino acid residues. It was found that the enzyme can exist in two molecular forms.

Amino Acids↗
PubMedDate not supplied

[Comparative study of the proteolytic activity of staphylococci and detection of a specific protease].

Staphylococci of 194 strains and of different origin were tested for the presence of active extracellular protease. Activity of protease from Staphylococcus aureus was found to be significantly higher than that of Staphylococcus epidermidis. The culture that was isolated and characterized proved capable to produce an enzyme of high activity and narrow substrate specificity towards bonds formed by the COOH-group of dicarboxylic amino-acids. The protease within the staphylococcal cell was shown to be linked with the peripheral integral membrane proteins solubilized by 1% Triton X-100.

Amino Acids, Dicarboxylic↗