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Biomedical subjects

V A Krasil'nikov

Publications and source records attributed to V A Krasil'nikov.

8 recordsLinked to original sources
PubMed1989

[Effect of cycloheximide on lipid metabolism in cells, nuclei and subcellular fractions in the rat liver].

Well coordinated stages of inhibition, restoration and stimulation of protein, DNA and RNA synthesis were observed after administration of cycloheximide (3 mg/kg). The changes in lipid synthesis and composition in the nuclei and intranuclear structures were studied at different stages of cycloheximide action. The accumulation and stimulation of lipid synthesis in the nuclei during the inhibition and restoration of protein and DNA syntheses were followed by electron microscopy and labeled precursors methods. Dramatic changes were observed in the phospholipid composition of chromatin and nuclear matrix. The accumulation of minor phospholipid fractions in intranuclear structures was observed during DNA synthesis. The sphingomyelin concentration was predominant and commensurable with those of phosphatidylcholine and phosphatidylethanolamine.

Animals↗
PubMed1984

[Sequential activation of various types of nuclear RNA polymerases of rat liver cells during the process of DNA synthesis induction by cycloheximide].

The dynamics of changes in the activity of RNA polymerases I and II (EC 2.7.7.6) and the activities of free and bound forms of RNA polymerase II in isolated rat liver nuclei after a singular injection of sublethal dose of cycloheximide (CHI) was studied. Activation of RNA polymerases occurs in three steps. The first step (1--2 hours after CHI injection) coincides with inhibition of protein synthesis and predominant activation of both forms of RNA polymerase II. The second step (6--24 hours after CHI injection) is characterized by de novo protein synthesis and activation of RNA polymerase I and RNA polymerase II. The third step (36--48 hours after CHI injection) witnesses activation of both RNA polymerases which coincides with the beginning of stimulation of DNA replication. It is assumed that this step is coupled with the synthesis of a special form of RNA polymerase, RNA polymerase IV, which is responsible for transcription of genes synthesizing various chromatin components (histones, NHB, RNA prime). At all steps the activity of free RNA polymerase II remains at a sufficiently high level. Consequently, the activity of chromatin is limited by chromatin structure rather than by RNA polymerase II content in it. Presumably, such activation of various forms of RNA polymerase is essential for cell preparation for DNA replication.

Animals↗
PubMed1981

[Functional and structural changes of E. coli membranes induced by low temperature freezing].

Low temperature freezing of E. coli cells causes a fall in endogenous respiration and stimulation of respiration by the non-penetrant substrate NADH. This decrease is not due to disturbances in the function of electron transport chain, since the dehydrogenase and oxidase activities and cytochrome content in the membranes of intact and frozen cells are practically the same. Frozen E. coli cells are incapable of ATP synthesis by artificial proton motive force, although the ATPase activity of isolated membranes is not changed. The disturbances in the penetrability barrier of protons after freezing can be revealed from changes in pH of cell suspensions after rapid acidification. It is assumed that the cell penetrability barrier undergoes alterations causing a loss of respiration substrates and, probably, oxidative phosphorylation uncoupling. A correlation between constant damages of the membrane penetrability barrier and cell survival was established. Using spin labelling of different localization, the changes in the state of membrane surface at the intact hydrophobic lipid zone were demonstrated. It was found that freezing does not induce lipid peroxidation.

Adenosine Triphosphatases↗
PubMed1978

[Stimulation of nuclear membrane components and DNA biosynthesis in rat liver cells after inhibition of translation with cycloheximide].

After a drastic inhibition of protein synthesis (95%) in rat liver by cycloheximide (0.2-0.4 mg/100 g of body weight) the recovery and subsequently prolonged marked stimulation of proteins, lipids and DNA were found. The correlation of nuclear membrane proteins and lipids synthesis was observed in a recovery and stimulation phases. Nuclear DNA synthesis increases after the stimulation biosynthesis of nuclear membrane components (36-40 hours after cycloheximide injection). The changes of a phospholipid composition and structure organisation of nuclear membrane hydrophobic zones (by spin probe) were found in stimulated DNA synthesis (48-60 hours).

Animals↗