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Biomedical subjects

A V Oleskin

Publications and source records attributed to A V Oleskin.

7 recordsLinked to original sources
PubMed2000

Programmed cell death.

This paper reviews data on programmed cell death (apoptosis) in animals and plants. Necrosis is a pathological scenario of cell death, which entails an inflammatory response in animal tissues. Apoptosis results in the disintegration of animal/plant cells into membrane vesicles enclosing the intracellular content, which are thereupon engulfed by adjacent or specialized cells (phagocytes) in animals. Plants lack such specialized cells, and plant cell walls prevent phagocytosis. The paper considers the main molecular mechanisms of apoptosis in animals and the pathways of activation of caspases, evolutionarily conserved cysteine proteases. A self-contained section concerns itself with the process of programmed cell death (PCD) in microorganisms including: 1) cell death in the myxomycete Dictyostelium discoideum and the parasitic flagellate Trypanosoma cruzi; 2) PCD in genetically manipulated yeast expressing the proapoptotic Bax and Bak proteins; 3) the death of a part of a prokaryotic cell population upon the depletion of nutrient resources or under stress; 4) the elimination of cells after a loss of a plasmid encoding a stable cytotoxic agent in combination with an unstable antidote; and 5) PCD in phage-infected bacterial cells.

Animals↗
PubMed1988

[Quinones and their interactions with enzyme complexes of energy-transducing biomembranes].

The functionally essential properties of biomembrane quinones and the mechanism of their interaction with protein components are discussed. The hypotheses on the mobile quinone pool or the ability of protein-bound quinones to transfer redox equivalents in biomembranes are discussed. The idea of quinone domains is invoked, and evidence is provided for the presence of such domains in operative biomembranes.

Animals↗
PubMed1983

The dibromothymoquinone effect on membrane potential generation in Rhodospirillum rubrum chromatophores.

2,5-Dibromo-3-methyl-6-isopropyl benzoquinone (DBMIB) inhibits the light-dependent membrane potential generation in Rhodospirillum rubrum chromatophores. The inhibition is relieved by electron donors and is obviously due to oxidation of the photosynthetic electron transfer chain components. In addition, high DBMIB concentrations elicit another effect probably caused by disruption of quinone functions in chromatophores. However, in quinone-depleted chromatophores and proteoliposomes containing the P-870 reaction center and light-harvesting antenna complexes, DBMIB stimulates membrane potential generation in the light, probably restoring some of the quinone-dependent processes in the membrane. DBMIB inhibits the inorganic pyrophosphate- and ATP-induced membrane potential generation in chromatophores.

Adenosine Triphosphate↗
PubMed1983

[Effect of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, a ubiquinone analog, and SH-reagents on the electrogenic function of pyrophosphatase from Rhodospirillum rubrum chromatophores].

Inorganic pyrophosphate-induced membrane potential generation in Rhodospirillum rubrum chromatophores is inhibited by 2,5-dibromo-2-methyl-6-isopropyl-p-benzoquinone (DBMIB). The inhibition is increased by menadione and dithionite and is not relieved by ascorbate; this effect is probably due to a displacement of the intrachromatophore quinones by DBMIB. The SH-reagents, N-ethylmaleimide and p-chloromercurybenzoate at high concentrations inhibit membrane potential generation driven by inorganic pyrophosphate hydrolysis, thus suggesting the involvement of SH-groups in pyrophosphatase operation. The mechanism of regulation of the mode of action of pyrophosphatase by quinones and the location of the SH-groups of the enzyme are discussed.

Bacterial Chromatophores↗
PubMedDate not supplied

[Colonial organization and intercellular communication of microorganisms].

This review covers the modern concepts and recent data demonstrating the integrity and coherence of microbial populations (colonies, biofilms, etc.) as peculiar "super-organisms." Special attention is given to such relevant phenomena as apoptosis, bacterial altruism, quorum effects, collective differentiation of microbial cells, and the formation of population-level structures such as an extracellular matrix. Emphasis is placed on the channels in colonies and agents of intercellular communication in microbial populations. The involvement of a large number of evolutionarily conserved communicational facilities and patterns of intercellular interactions is underscored. Much attention is also given to the role of colonial organization and intercellular communication in parasite/commensal/symbiont-multicellular host organism systems.

Apoptosis↗
PubMedDate not supplied

[Effect of serotonin (5-hydroxytryptamine) on the growth and differentiation of microorganisms].

Serotonin (5-hydroxytryptamine), a neurotransmitter and social behavior factor in higher animals, accelerates culture growth and induces cell aggregation in Escherichia coli and Rhodospirillum rubrum at concentrations of 2 x 10(-7)-2 x 10(-5)M. In the myxobacterium Polyangium sp., 10(-6)-10(-5)M serotonin stimulates cell aggregation and myxospore formation. At concentrations over 20 microM, serotonin induces the opposite effect: it inhibits cell aggregation and microbial culture growth. Serotonin at these concentrations also inhibits the light-dependent membrane potential generation in Rsp. rubrum (the data were obtained by the method of penetrating ions). Therefore, the above effects can be due to the elimination of the transmembrane electrical gradient by serotonin. As for micromolar serotonin concentrations, their effects presumably result from the specific action of serotonin as an intercellular communication agent accelerating and possibly synchronizing the development of the cell population.

Cell Division↗