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N A Polteva

Publications and source records attributed to N A Polteva.

7 recordsLinked to original sources
PubMed1997

Polypeptide composition of submitochondrial fractions of normal liver tissue and Zajdela hepatoma.

The polypeptide composition of liver and Zajdela hepatoma mitochondria is compared. Polypeptides of mitochondria and submitochondrial fractions (the outer and the inner mitochondrial membranes, the intermembrane and the matrix spaces of mitochondria) were separated by electrophoresis in polyacrylamide gel. The percentage content of each polypeptide was evaluated after scanning gels using a differential spectrophotometer-densitometer. Significant changes of several proteins of the hepatoma mitochondria and submitochondrial fractions as compared with normal liver preparations have been found.

Animals↗
PubMed1994

Changes in phospholipids during the cell cycle of myxomycete Physarum polycephalum.

The rate of 32Pi incorporation into the main membrane phospholipid fractions, i.e. phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI), as well as their contents in the cells during synchronous growth of the myxomycete, Physarum polycephalum, have been studied. It has been found that both the phospholipid levels and the rates of 32Pi incorporation increase during the S phase till the early G2 phase, remain nearly constant during the G2 phase and fall to the initial level at the end of the G2 phase and in mitosis. It has been revealed that the rate of 32Pi incorporation into PC is very low compared to PE and PI, in spite of the fact that the PC level is the highest. The possible reasons of this phenomenon are discussed.

Animals↗
PubMed1979

[Effect of the respiratory chain redox state on mitochondrial membrane permeability for K+ ions].

Transport of Pi into mitochondrial matrix induces K+-permeability of the membranes, which results from the addition of DNP. This induction of K+ efflux is eliminated by some agents causing the respiratory chain reduction (e.g. succinate, rotenone, antimycin A). It was shown that the abolition of the membrane potential is not sufficient for K+ efflux induction. The latter process is necessary for the energy-linked formation of the K+-transporting system. The lipid fraction containing lecithin and monophosphoinositol was extracted from the mitochondria after preincubation with Pi. The artificial bilayer membranes formed from these lipids are permeable for K+.

Animals↗
PubMedDate not supplied

[Interaction of caffeine with basic nucleic acids my a molecular mechanic method].

To understand some aspects of the biological action of caffeine (CAF), the interaction energies for various mutual positions of CAF and DNA bases or basepairs were calculated. Three types of mutual CAF-base (CAF-basepair) arrangements corresponding to the minima of interaction energy were revealed. One type of minima correspond to the stacking arrangement of molecules. This type is important for interactions of CAF with DNA monomers and single-stranded fragments. The other two types of minima correspond to the formation of intermolecular hydrogen bonds. Some of these minima may occur during the interaction of CAF with the double helix. One of these types corresponds to the nearly in-plane position of molecules. The other type of minima correspond to the nearly perpendicular arrangement of molecule planes. The minima of the last type are supposed to be the most important for the interaction of CAF with the DNA duplex, and interaction energies for this type of minima have the most negative values.

Caffeine↗
PubMedDate not supplied

[Interactions of caffeine with DNA double helix fragments. Molecular mechanics simulation].

Calculations of the energy of interaction between the caffeine molecule and DNA double helix fragment of four complementary pairs have been performed by the molecular mechanics method. The calculations demonstrate the existence of energy minima corresponding to the caffeine molecule position in both wide and narrow grooves. Each of three proton acceptor atoms of caffeine is able to form hydrogen bond with each of three amino groups of DNA bases. The interactions of caffeine with both hydrogen bonded nucleotide and other nucleotides of the two strands contribute considerably to the total energy. The substantial contribution of interactions of caffeine with other than H-bonded nucleotides results in a rather close packing of atom groups in possible DNA-caffeine complexes. The mechanisms of influence of caffeine on interactions of DNA with other biologically active compounds are discussed.

Caffeine↗
PubMedDate not supplied

[Metabolite level from energy metabolism in Escherichia coli cells during growth on various substrates].

In the present work, an attempt has been made to analyse some parameters of the intracellular energy metabolism and to determine whether they are related to the cell growth rate. The authors measured intracellular concentrations of adenine nucleotides, the content of glycogen, an energy "depot" of glucose, the rate of its synthesis, and the content of glutathione which specifies the redox state in the cytoplasm of E. coli cells upon continuous cultivation on a minimal nutrient medium containing various carbon sources (glucose, glycerol, lactate, and acetate). It was found that the specific contents of adenine nucleotides and reduced glutathione were independent of the cell growth rate. Based on the results obtained, it is assumed that a possible reason for changes in the duration of the sell cycle of the bacteria cultured on different substrates is an alteration in the content of reserve carbohydrates.

Culture Media↗