[A role for calreticulin in functioning of mitochondrial ATP-dependent potassium channel].

Homology of the amino acid sequence of the mitochondrial potassium-transporting protein (MW 57kDa), having the properties of a channel subunit of the mitochondrial ATP-dependent potassium channel, and calreticulin (MW 55kDa) was detected by MALDI-TOF-TOF analysis method. Inhibitory analysis of ATP-dependent potassium transport in mitochondria with polyclonal antibodies to calreticulin was carried out. A dose-dependent inhibition of potassium transport in mitochondria by these antibodies was shown. The maximum value of inhibition was 55-60%. Based on these data it is hypothesized that at least two types of ATP-sensitive potassium channels are localized in mitochdndrial membrane. It is expected that the type of mitochondrial ATP-dependent potassium channel, which includes homologous calreticulin protein is localized mainly at mitochondrial and reticulum membrane contact sites.

Oxidative phosphorylation and ion transport in the mitochondria of two strains of rats varying in their resistance to stress and hypoxia.

The role of mitochondria in the inherited or ontogenetically acquired reactions of organism to stress is not studied enough. In the present work, we examined the functional state of the coupled respiratory chain, potassium and calcium transport and rate of hydrogen peroxide production on two rat lines: August and Wistar-which possess different resistance to emotional stress and hypoxia. It was established that the respiration rate and efficiency of oxidative phosphorylation were higher in August rats than in Wistar ones. In August rats, the rate of potassium transport and ATP-dependent mitochondrial swelling as well as the concentration of the ion in the mitochondrial matrix were almost twice as higher comparatively to those parameters in Wistar rats. The rate of H2O2 production was found to be decreased in the mitochondria of August rats. It was also demonstrated that the two rat lines differed by their resistance to the opening of the palmitate/Ca(2+)-induced pore and by their ability to retain calcium within mitochondria. The paper discusses the involvement of the mitochondrial ATP-dependent potassium channel in the adaptation of animals to adverse effects.

Activity of mitochondrial ATP-dependent potassium channel in animals with different resistance to hypoxia before and after the course of hypoxic training.

Activity of mitochondrial ATP-dependent potassium channel in rats with high genetically determined resistance to hypoxia was higher than in sensitive animals. Adaptation of low resistant rats to hypoxia was accompanied by activation of the channel, facilitation of potassium recycling in mitochondria, and a decrease in the rate of H2O2 formation. Our results indicate that mitochondrial ATP-dependent potassium channel plays an important role in the delayed mechanisms of animal's adaptation to hypoxia.

[Age-related changes in the functioning of the mitochondrial potassium-transporting system].

Changes in the rate of respiration and functioning of the ATP-dependent potassium channel the liver and heart mitochondria of one-, three-, eight-, and twenty four-month-old Wistar male rats have been investigated. It was shown that the activity of the channel in the mitochondria of both tissues in 24-months-old animals decreases more than three times, and the content of potassium, 1.5-2 times compared with young one-month-old rats. The changes occur against the background of age-related decrease of energy supply in mitochondria, the respiratory complex-I underganig the greatest changes upon aging. The decrease of channel activity may be the result of changes in channel sensitivity to modulators and a decrease in the expression of mitochondrial K(+)-transporting channel-protein with a molecular mass of 5.5 kDa upon aging found in this work. As a result, the functioning of not only the mitoK(ATP) but also the whole mitochondrial potassium cycle is impaired.

Effect of several flavonoid-containing plant preparations on activity of mitochondrial ATP-dependent potassium channel.

Flavonoid-containing plant preparations (water soluble extracts of Pentaphylloides fruticosa [Extralife], Emblica officinalis Gaerth [Amla], and Bergenia crassifolia [Bergenia]) produced a dose-dependent and tissue-specific effect on activity of mitochondrial ATP-dependent potassium channel. The effect of these preparations was biphasic (activation and inhibition). The activating effect of Extralife was one order of magnitude higher than that of Amla and Bergenia and was observed in a wider concentration range. The activating effect of preparations was abolished by inhibitors of the mitochondrial ATP-dependent potassium channel, which attested to specificity of their influence on mitochondrial channel. Under in vivo conditions, the antihypoxic effect of Extralife was partially abolished by mitochondrial ATP-dependent potassium channel inhibitor 5-hydroxydecanoate.

[Antibiotic properties of cultures of the Streptomyces coelicolor group that suppress the growth of strains of the same species]. / Antibioticheskie svoistva kul'tur gruppy Streptomyces coelicolor, ugnetaiushchie rost shtammov togo zhe vida.

Antimicrobial spectrum of 45 cultures of the S. coelicolor group with respect to closely related strains and other streptomycete species was studied. The spectrum of 7 cultures was narrow and they inhibited closely related strains and certain streptomycete species. These cultures produced antibiotic substances of bacteriocin-like nature. The bacteriocin-like substances of the cultures differed in sensitivity to temperature and proteolytic enzymes and capacity for dialysis through cellophane membranes. Biosynthesis of the antibiotic substances increased after exposure to UV light.

[Isolation and characteristics of Saccharomyces cerevisiae strains with increased sensitivity to detergents]. / Poluchenie i kharakteristika shtammov drozhzhei Saccharomyces cerevisiae s povyshennoi chuvstvitel'nost'iu k detergentam.

The yeast mutants possessing enhanced sensitivity to detergents were obtained after treatment with ethyl methanesulfonate. The whole set of mutants may be divided into three groups, according to sensitivity to: cetylthreemethylammonium chloride detergents and dyes of the ethidium bromide type, detergents, dyes and antibiotics (gramycidin C and actinomycin D). The genetic analysis performed indicated that more than one gene are responsible for sensitivity. On the basis of the test for allelism mutants were distributed into three groups. It was shown that ethidium bromide is far more potent inducer of cytoplasmic petites in detergent-sensitive than in wild-type strains.

[Mutagenic activity of the fungicide captan]. / K voporsu o mutagennoi aktivnosti fungitsida kaptana.

A complex study of mutagenic activity of captan (a fungicide) in a series of standard test-systems has shown that the preparation induces gene mutations in certain Salmonella indicator strains (without metabolic activation), increases the frequency of mitotic crossing-over and gene conversion in yeasts (Saccharomyces), possesses a weak cytogenetic action on bone marrow cells in experimental animals, manifests no cytogenetic effect in the lymphocyte culture of human peripheral blood (including a system of microsomal activation). Genetic activity of captan cannot be a limiting criterion of its harmfulness.

[Effect of nitrosourea in small doses on the frequency of mutation in Salmonella typhimurium]. / Vliianie nitrozomocheviny v malykh dozakh na chastotu mutatsii u Salmonella typhimurium.

The effect of N-nitroso-N-methylurea (NMU), N-nitroso-N,N'-dimethylurea (NDMU) and N-nitroso-N-ethylurea (NEU) at doses less than 100 mkg/ml on mutability of Salmonella typhimurium strains of Ames' system (G-46, TA-1950, TA-1535, TA-100, TA-1538) has been studied. NMU and NEU at doses of 5-10 mkg/ml have been found to increase the survival and decrease the number of reversions from auxotrophity in histidine to prototrophity. The effect of given doses of NMU and NEU on bacteria repair activity has been shown. The role of pk M101 plasmide in this process is being discussed. NDMU in contrast to NMU and NEU induces read frome shift mutations and exhibits high mutagenous activity at all doses examined.

[Effect of nonmutagenic doses of 1,4-bis-diazoacetylbutane on Streptomyces griseus]. / Vliianie na Streptomyces griseus nemutagennykh doz 1,4-bis-diazoatsetilbutana.

Streptomyces griseus 15 was subjected to the action of 1,4-bis-diazoacetyl butane (DAB) taken at concentrations of 10 to 50,000 micrograms/ml. Small doses (10-100 micrograms/ml) of DAB had no mutagenic action and activated the cultural growth (the viability and the survival rate of spores increased on solid media, while the biomass yield rised in liquid media). Experiments were conducted using the method of orthogonal planning of a bifactorial experiment, and the role of the exposure time rised with a decrease in the mutagen concentration.

[Comparative study of the mutagenic activity of organophosphate insecticides on bacteria]. / Sravnitel'noe izuchenie mutagennoi aktivnosti nekotorykh fosfororganicheskikh insektitsidov na bakteriiakh.

Mutagenic activity of the organo-phosphorus insecticides, metaphos, phosphamide and carbophos, on indicator Salmonella typhimurium TA-1535 strain is shown which is determined without metabolic activation. It is established that all the three preparations induce direct mutations in Pseudomonas aeruginosa. The quantity of visible mutations increases with the prolongation of exposure time and the insecticide concentration. Metaphos and phosphamide induced auxotrophic mutations. Phosphamide has the highest mutagenic activity in the assays with bacterial systems.

[Effect of heredity on cattle morbidity from brucellosis]. / Vliianie nasledstvennosti na zabolevaemost' krupnogo rogatogo skota brutsellezom.

A high constancy of diversity was found in the genealogical groups in respect to the brucellosis incidences. It is caused by the influence of sires. The frequency of brucellosis is significantly dependent on the year of birth, paternity and the interaction of the father's genotype with the year of birth of the daughters.