Sugar transport regulation in vitro by new calcium ionophores

The influence of calcium ionophores--tenoyltrifluoroacetate (TTFA) and divaleryldibenzo-18-crown-6(divaleryl) on the glucose consumption, D-xylose transport and glycogen content in rat diaphragm was studied. TTFA caused a clear dose-dependent inhibition of carbohydrate transport and glycogenolysis stimulation. Divaleryl, on the other hand, raised glucose consumption, D-xylose transport without influencing glycogen content. Exclusion of Ca++ from incubation medium increased the TTFA inhibiting effect on glucose consumption, decreased its glycogenolytic effect and removed divaleryl induced stimulation of glucose transport. Mechanisms of calcium ionophore action and a possible role of intracellular Ca2+ in carbohydrate transport are discussed.     

The structure of DNA-DOPC aggregates formed in presence of calcium and magnesium ions: a small-angle synchrotron X-ray diffraction study

The structure of aggregates formed due to DNA interaction with dioleoylphosphatidylcholine (DOPC) vesicles in presence of Ca(2+) and Mg(2+) cations was investigated using synchrotron small-angle X-ray diffraction. For DOPC/DNA=1:1 mol/base and in the range of concentration of the cation(2+) 0-76.5 mM, the diffractograms show the coexistence of two lamellar phases: L(x) phase with repeat distance d(Lx) approximately 8.26-7.39 nm identified as a phase where the DNA strands are intercalated in water layers between adjacent lipid bilayers, and L(DOPC) phase with repeat distance d(DOPC) approximately 6.45-5.65 nm identified as a phase of partially dehydrated DOPC bilayers without any divalent cations and DNA strands. The coexistence of these phases was investigated as a function of DOPC/DNA molar ratio, length of DNA fragments and temperature. If the amount of lipid increases, the fraction of partially dehydrated L(DOPC) phase is limited, depends on the portion of DNA in the sample and also on the length of DNA fragments. Thermal behaviour of DOPC+DNA+Ca(2+) aggregates was investigated in the range 20-80 degrees C. The transversal thermal expansivities of both phases were evaluated.     

Analysis of the hemochromatosis gene (HFE) mutations, C282Y and H63D, in the populations of Central Asia

Analysis of the C282Y and H63D mutations in the HFE gene was carried out in 594 individuals representing seven indigenous populations of Central Asia. Among the populations examined, mutation C28Y was found in Uighurs with the frequency of 0.009, and in Kazakhs and Tajiks with the frequency of 0.012. The mutation was absent in Uzbeks, Kyrgyzes, Kurds, and Turkmens. Mutation H63D was detected in all populations studied with the frequencies ranging from 0.024 (Tajiks) to 0.139 (Turkmens). Judging by the frequencies of the mutations of interest, the populations examined occupied the intermediate position between the European and Eastern Asian populations, which corresponded to their geographical position.     

Analysis of Alu-insertion polymorphism in three subethnic groups of Kalmyks

Eight Alu insertions at the NBC27, TPA25, NBC148, NBC123, ACE, APOA1, NBC51, and PV92 locus were examined in three subethnic groups of Kalmyks (Torgouds, Derbets, and Buzava). In general, the pattern of allele frequencies in Kalmyks was consistent with that in Asian populations of the world, and was similar to the Alu insertion frequencies pattern in Turkic populations of the Volga-Ural region and Central Asia. Pairwise comparisons of three subpopulations of Kalmyks with respect to the frequency distributions of eight Alu insertions revealed the differences between the groups examined. The coefficient of gene differentiation, F _st, constituted 1.37%, pointing to the common origin of the groups of interest, as well as to the uniformity of the gene pools of subethnic groups of Kalmyks examined.     

Genetic characterization of Balkars and Karachays according to the variability of the Y chromosome

The genetic diversity in two ethnic groups of the central part of the North Caucasus (Balkars and Karachays) using 50 diallelic loci in the non-recombining region of the Y chromosome was analyzed. For the first time, an analysis of distribution of frequencies of Y-chromosome haplogroups in Balkars considering different subethnic groups (Baksans, Chegems, Kholams, Bezengiyevs, and Malkars) was conducted. The major Y-chromosome haplogroups in the studied groups of Balkars and Karachays were G2a-P16 and R1a- Z2123. In addition, for a better understanding of genetic relationship between the male lineages in the studied populations and other populations of the Caucasus, we performed an analysis of R1a-M198 subhaplogroups in 22 populations of this region. The principal component analysis demonstrated that a greater difference was observed between Kholams and the other Balkar subgroups. According to the F _st analysis, Chegems, for which the prevalence of haplogroup R1b-M478 (32.2%) was reported, demonstrated the maximum difference from the other subpopulations of Balkars and Karachays.     

Spin isomeric selectivity of water molecules upon DNA hydration

Four-photon coherent scattering of laser radiation was used to study the influence of DNA on the content of quasi-free ortho and para isomers of water molecules in its aqueous solution. It was shown that the concentration of quasi-free molecules that form the rotational spectrum of spin isomers increases considerably in the hydration shell of the DNA molecule as compared with pure water. The increase in the concentration of spin isomers occurs disproportionally. In the presence of DNA, the intensity of the rotational spectrum of ortho isomers is on the average much greater than that of para isomers. It was also demonstrated that the character of hydration and the ortho/para ratio change noticeably upon DNA denaturation, which may be evidence of changes in preferable solvation of DNA during its denaturation. The data obtained allowed us to assume that the stability of different biologically important states of macromolecules can be changed by varying the relative concentration of water spin isomers in solution.     

Analysis of the hemochromatosis gene (HFE) mutations, C282Y and H63D, in the populations of Central Asia

Analysis of the C282Y and H63D mutations in the HFE gene was carried out in 594 individuals representing seven indigenous populations of Central Asia. Among the populations examined, mutation C282Y was found in Uighurs with the frequency of 0.009, and in Kazakhs and Tajiks with the frequency of 0.012. The mutation was absent in Uzbeks, Kyrgyzes, Kurds, and Turkmens. Mutation H63D was detected in all populations studied with the frequencies ranging from 0.024 (Tajiks) to 0.139 (Turkmens). Judging by the frequencies of the mutations of interest, the populations examined occupied the intermediate position between the European and Eastern Asian populations, which corresponded to their geographical position.     

The structure of DNA-DOPC aggregates formed in presence of calcium and magnesium ions: A small-angle synchrotron X-ray diffraction study

The structure of aggregates formed due to DNA interaction with dioleoylphosphatidylcholine (DOPC) vesicles in presence of Ca²⁺ and Mg²⁺ cations was investigated using synchrotron small-angle X-ray diffraction. For DOPC/DNA = 1:1 mol/base and in the range of concentration of the cation²⁺ 0-76.5 mM, the diffractograms show the coexistence of two lamellar phases: L^x phase with repeat distance d_Lx ∼ 8.26-7.39 nm identified as a phase where the DNA strands are intercalated in water layers between adjacent lipid bilayers, and L_DOPC phase with repeat distance d_DOPC ∼ 6.45-5.65 nm identified as a phase of partially dehydrated DOPC bilayers without any divalent cations and DNA strands. The coexistence of these phases was investigated as a function of DOPC/DNA molar ratio, length of DNA fragments and temperature. If the amount of lipid increases, the fraction of partially dehydrated L_DOPC phase is limited, depends on the portion of DNA in the sample and also on the length of DNA fragments. Thermal behaviour of DOPC + DNA + Ca²⁺ aggregates was investigated in the range 20-80 °C. The transversal thermal expansivities of both phases were evaluated.     

Analysis of polymorphism at nine nuclear genome DNA loci in maris

Population genetic survey of the indigenous populations of the Marii El Republic, represented by the two major ethnographic groups of Maris, Meadow (five samples from Morkinsk, Orshansk, Semursk, Sovetsk, and Zvenigovsk districts) and Mountain (one sample from Gornomariisk district) Maris, was carried out. All Mari groups were examined at nine polymorphic DNA loci of nuclear genome, VNTR(PAH) (N = 422), STR(PAH) (N = 152), VNTR(ApoB) (N= 294), VNTR(DAT1) (N = 363), VNTR(eNOS) (N = 373), ACE (N = 412), IVS6aGATT (N = 513), D7S23(KM.19) (N = 494), and D7S8 (N = 366). Allele and genotype frequency distribution patterns were obtained for individual samples and ethnographic groups, as well as for the ethnic group overall. In each of six Mari samples examined, the deficit of heterozygotes was observed, i.e., the mean observed heterozygosity was lower than the expected one. The indices of mean heterozygosity, Hs = 0.455, and interpopulation differentiation, FST = 0.0024, for the Mari gene pool were obtained using a set of DNA markers analyzed. Analysis of the genetic distances and between population differentiation (FST) showed that the main part of genetic diversity in Maris was determined by the differentiation between the populations of Meadow Maris. The contribution of the differences between the ethnographic groups of Mountain and Meadow Maris to the ethnic gene pool was small. It is suggested that the main role in the formation of the Mari gene pool is played by the geographic factor.     

Analysis of the IT15 Gene in Huntington's Disease Families

Direct molecular genetic testing carried out in 59 Huntington's disease patients belonging to 46 families from Bashkortostan revealed the (CAG) _n repeat expansion in exon 1 of the IT15 gene in 57 of them. By use of this analysis the disease status was not confirmed in two patients with atypical form of the disease and negative family history. The (CAG) _n repeat expansion was identified in 27 out of 127 asymptomatic at-risk individuals. Analysis of the mutant (CAG) _n allele inheritance demonstrated extremely high instability and high mutation rate predominantly leading to the appearance of the alleles with increasing number of (CAG) _n repeats in subsequent generations. The instability was mostly observed in cases of paternal transmission. Almost complete linkage disequilibrium between the (CCG)₇ mutant alleles and the del2642 deletion was demonstrated. Three major haplotypes revealed, (CCG)₇/del–, (CCG)₇/del+, and (CCG)₁₀/del–, implied the existence of at least three sources of the origin of Huntington's disease in Bashkortostan. The identified haplotype frequency distribution patterns displayed similarities with those in European populations. The contribution of a number of genetic factors to the age of onset of Huntington's disease was analyzed.