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V N Orlov

Publications and source records attributed to V N Orlov.

At least 37 records · Page 2Linked to original sources
PubMed1996

Interaction of myosin subfragment 1 with F-actin studied by differential scanning calorimetry.

The thermal unfolding of the myosin subfragment 1 (S1) and of filamentous actin (F-actin) in their strong complex obtained in the presence of ADP was studied by differential scanning calorimetry (DSC). It is shown that in the acto-S1 complexes S1 and F-actin melt separately, and thermal transitions of each protein can be easily followed. Interaction of S1 with F-actin significantly increases S1 thermal stability and also affects the thermal stability of F-actin. Although S1 unfolds at much lower temperature than F-actin, the molecules of S1 remain bound to F-actin even after full denaturation. Under these conditions S1 may induce cross-linking between actin filaments. It is concluded that DSC studies on the acto-S1 complexes offer a new and promising approach to investigate the structural changes which occur in the myosin head and in F-actin due to their interaction.

Actins↗
PubMed1994

Combination of the electrogenic ionophores, valinomycin and CCCP, can lead to non-electrogenic K+/H+ exchange on bilayer lipid membranes.

The method of pH shift measuring by means of a pH microelectrode was applied to measure hydrogen ion fluxes across a planar bilayer lipid membrane (BLM) in the presence of the potassium ion ionophore, valinomycin, and a protonophore, carbonylcyanide m-chlorophenylhydrazone (CCCP), under conditions of the voltage clamp. The voltage dependence of the flux was determined to be in the range of +/- 150 mV under the conditions of both symmetrical KCl as well as a KCl gradient across the BLM. Surprisingly, at a clamped zero voltage on BLM a significant hydrogen ion flux was observed in the presence of a KCL gradient and both valinomycin and CCCP. This finding was interpreted as a result of induction of non-electrogenic K+/H+ exchange in the presence of valinomycin and CCCP, presumably through the formation of electrically neutral complexes of these two ionophores and K+ (H+) ions: valinomycin-K(+)-CCCP- and/or possibly valinomycin-CCCP(-)-H+.

Carbonyl Cyanide m-Chlorophenyl Hydrazone↗
PubMed1994

[Population-genetic variability of the house mouse Mus musculus L. 1758 S. stricto from the western, central, and southeastern area of species range].

Allozyme variation in nine populations of the house mouse Mus musculus L. s. str. was examined. Twenty-five out of 34 analyzed loci were shown to be polymorphic. Estimates of genetic variation were obtained for separate populations and for population groups classified according to their habitat. Populations from Moldova and Tadzhikistan displayed the lowest and highest amounts of allozyme variation, respectively. Variation in town populations was significantly greater than in rural ones. This can be explained by active human-induced migration of mice into towns. All Central Asian populations showed high levels of genic diversity, which is presumably related to their proximity to ancient centers of mice expansion. Allelic distributions in the populations were analyzed.

Animals↗
PubMed1994

[Allozyme variability of the European bean Castor fiber 1758 (Castoridae, Rodentia) from the Voronezh State Nature Reserve].

Electrophoretic methods were used to study protein products of 32 gene loci in the blood of European and Canadian beavers held in captivity at the Voronezh State Nature Reserve. In the studied samples, the levels of polymorphism and average heterozygosity exceeded the average values of corresponding indices determined for beavers that inhabit temperate zones. To what extent the studied samples represent the state of the gene pool of parental populations is discussed. A comparison between allozyme spectra of samples of European and Canadian beavers revealed many coinciding polymorphic loci, on the one hand, and pronounced genetic divergence of these species, on the other.

Animals↗
PubMed1993

[Behavior of pachytene chromosomes in male mice heterozygotic for various translocations (Rb(8,17), T(16,17)43H)].

The electron microscopic analysis of synaptonemal complexes of the Robertsonian translocation heterozygotes (Rb/T) and heterozygotes of the reciprocal translocation (Rb(8, 17)/T(16, 17) 43H revealed three types of translocation configurations (TC). The observed TC were subdivided into three types according to the manner of synapsis: 1) full synapsis of homologues forming trivalent with interstitial centromere in 15%; 2) the centromeric asynapsis (8 and 17-16 chromosomes forming trivalent with the extension region of asynapsis and breakpoint of the reciprocal translocation on chromosome 17 in 70%; 3) centromeric asynapsis (only single chromosome 17-16 of trivalent, when the break point of reciprocal translocation and the absence of centromeric asynapsis of another chromosome 8 formed trivalent in 15%). The frequency of association between trivalents and the XY bivalents is 20% and close proximity is 15% for heterozygotes Rb/T. Which are fertile, while in the sterile heterozygotes Rb(8, 17)/T(16, 17) 43H it is 45% for association and 15% close proximity (total 60%). These data show the significant differences in the contact of translocation configurations with the XY bivalents of fertile heterozygotes, in comparison with the sterile. Thus, it is shown that the chromosome pairing of fertile and sterile mice is clearly distinguished.

Animals↗
PubMed1990

[Relations between the duration of coupling interval and frequency fluctuations in ventricular ectopic complexes].

An attempt was made to electrocardiographically assess the likely mechanisms responsible for the occurrence of arrhythmias. The frequency of ventricular ectopic complexes was compared with fluctuations of coupling interval duration. An examination of 36 patients provided evidence for preliminary considerations concerning the causation between the frequency of ventricular ectopic complexes and the duration of coupling interval. The findings are promising from clinical and predictive points of view.

Adolescent↗
PubMed1990

[Characteristics of disorders of hemostasis and lipid metabolism in patients with different pathogenetic forms of angina pectoris].

The likely mechanisms responsible for the occurrence of angina pectoris, which were revealed by 24-hour ECG monitoring, were correlated with abnormalities in hemostasis and blood lipid spectrum. Changes in the blood lipid spectrum were demonstrated to play the leading role in the development of angina due to higher myocardial oxygen demand. Those in platelet hemostasis are mostly pronounced in impaired myocardial oxygen supply due to vessel spasm and/or formation of platelet aggregates.

Adult↗
PubMed1989

[Genetic analysis of complementation of t-haplotypes in mice].

Complementation for viability of the compounds tx/ty in complete lethal haplotypes t6, t12, tw5, tw12, tw18, tw73, twPa-1 belonging to the seven basic complementation groups was studied. In the overwhelming majority of crosses a lack of tx/ty offspring was revealed but there is also evidence of non-complete complementation of the tx/ty haplotypes, except for T/tw73XT/tw12, T/tw18XT/t12, T/tw73XT/tw18 crosses in which the level of complementation for viability exceeds 100%. The maternal effect for compound variability was significantly revealed in 9 out of the 19 matings. In addition, reciprocal matings of heterozygotes T/txXT/ty were tested for fertility. In two cases, the maternal effect was also revealed for this character. Comparison of data on viability of the compounds and the fertility of the original strains gives grounds to believe that the tx/ty haplotypes are not completely recessive and partially manifest themselves in the heterozygotes, decreasing fertility in a number of matings. In some cases, these t-haplotypes yield an effect, close to negative complementation, which may be associated with the interaction of the proteins of t-haplotypes.

Animals↗
PubMed1989

[Genetic analysis of fertility of male mice with various t-haplotypes].

Fertility of 47 mouse males carrying various combinations of lethal, t-haplotypes (t6/tw18, t12/tw18, Tw73/tw12, tw5/tw18, t6/dt5, t12/tw12, tw5/twPa-1, tw18/twPa-1, tw5/tw12) was studied in crosses with females of different genotypes. The t-haplotypes studied belong to 7 main groups of complementation. The presence of at least two factors of fertility in the t-complex was revealed. The influence of female genotype on the degree of male fertility was also demonstrated. The data presented confirm that different combinations of lethal complete t-haplotypes exhibit sterility, with the exception of t8/tw18 compound.

Animals↗
PubMed1988

[Correction of hypercholesterolemia and dyslipoproteinemia by plasmapheresis in patients with stenocardia resistant to drug therapy].

Plasmapheresis was used to correct blood lipid composition in patients with angina at rest and angina of effort (functional classes 3-4). In addition to a drop in total cholesterol and triglycerides, cholesterol in low and very-low-density lipoproteins fell abruptly, while high-density-lipoprotein cholesterol, on the contrary, increased considerably. Clinical improvement of the patients was also recorded.

Adult↗