<Emphasis Type="Italic">HTT</Emphasis> Gene Premutation Allele Frequencies in the Russian Federation

Huntington disease (Huntington chorea, HD) is a severe neurodegenerative disease determined by polyglutamine. Polyglutamine expansion in exon 1 of the HTT gene causes Huntington disease. To date, less than 35 CAG triplets are suggested to be present in normal alleles. Alleles bearing from 27 to 35 CAG repeats are generally considered as intermediate or premutation. Alleles with the number of CAG repeats varying from 36 to 39 demonstrate reduced penetrance and result in late manifestation of the disease. To date, no studies based on representative samples of Russian residents estimating the frequencies of premutation and alleles with reduced penetrance have been published. Meanwhile, this is extremely important for genetic counseling of patients bearing such alleles and for the calculation of risks for their offspring. In the present study, the analysis of samples of Russian patients with incoming diagnoses of Huntington chorea (N = 1092), Wilson–Konovalov disease (N = 333), Hallervorden–Spatz disease (N = 33) and a control group consisting of 230 unexamined individuals from the Russian Federation under 45 years of age was carried out. A spectrum of CAG repeat length in the HTT gene in patients with HD was obtained. Patients with HD were detected in the samples of patients with incoming diagnoses of Wilson–Konovalov disease and Hallervorden–Spatz disease. This observation indicates the complexity of differential diagnosis of these diseases. An assumption was made that an allele with 36 CAG repeats should be classified as premutation. We confirmed the previously observed trend for the increased number of CAG repeats in the case of paternal transmission of the mutant allele. The frequency of premutation allele of 2.6% in Russian residents was established.     

见血封喉乳汁脂溶性成分及其抗氧化活性研究

首次采用气相色谱.质谱联用技术(GC-MS)对见血封喉(Antiaris toxicaria(Pers.)Lesch.)乳汁的脂溶性成分进行了分析,共鉴定了27个化学成分,占其总量的91.7%.用清除DPPH自由基能力的方法测定了见血封喉乳汁脂溶性部位的抗氧化活性,结果显示出一定的抗氧化活性,SC50值为500μg ml-1.     

A study of polymorphism of the D2 dopamine receptor gene in the population of the Volga-Ural Region

Using polymerase chain reaction (PCR), TaqI polymorphism for the D2 dopamine receptor gene (DRD2) was studied in eight populations of the Volga-Ural region that belong to the Turkic (Bashkirs, Tatars, and Chuvashes), Finno-Ugric (Maris, Komis, Mordvinians, and Udmurts), and Eastern-Slavonic (Russians) ethnic groups. Significant differences in the distribution of genotype frequencies were found between the Tatar population belonging to the Turkic branch of the Altaic linguistic family and the Mari and Mordvinian populations belonging to the Finno-Ugric branch of the Ural family and between the Tatar and Bashkir populations belonging to the Turkic ethnic group.     

Molecular Hazard Identification of Non-O157 Shiga Toxin-Producing Escherichia coli (STEC)

The complexity regarding Shiga toxin-producing Escherichia coli (STEC) in food safety enforcement as well as clinical care primarily relates to the current inability of an accurate risk assessment of individual strains due to the large variety in serotype and genetic content associated with (severe) disease. In order to classify the clinical and/or epidemic potential of a STEC isolate at an early stage it is crucial to identify virulence characteristics of putative pathogens from genomic information, which is referred to as ‘predictive hazard identification’. This study aimed at identifying associations between virulence factors, phylogenetic groups, isolation sources and seropathotypes. Most non-O157 STEC in the Netherlands belong to phylogroup B1 and are characterized by the presence of ehxA, iha and stx ₂, but absence of eae. The large variability in the number of virulence factors present among serogroups and seropathotypes demonstrated that this was merely indicative for the virulence potential. While all the virulence gene associations have been worked out, it appeared that there is no specific pattern that would unambiguously enable hazard identification for an STEC strain. However, the strong correlations between virulence factors indicate that these arrays are not a random collection but are rather specific sets. Especially the presence of eae was strongly correlated to the presence of many of the other virulence genes, including all non-LEE encoded effectors. Different stx-subtypes were associated with different virulence profiles. The factors ehxA and ureC were significantly associated with HUS-associated strains (HAS) and not correlated to the presence of eae. This indicates their candidacy as important pathogenicity markers next to eae and stx _2a.     

Genetic distances and taxonomic analysis of human populations of the Volga-Ural region based on data on DNA polymorphism]

DNA polymorphism was studied in the human diallelic loci MET and D7S23 linked to the cystic fibrosis gene, diallelic locus PAH (the phenylketonuria gene), polyallelic locus ApoB, and hypervariable DNA sequences identified by means of DNA fingerprinting with phage M13 DNA as a probe. The obtained data were used to calculate genetic distances and perform taxonomic analysis of populations of the Volga-Ural region (Turkic and Finno-Ugric ethnic groups). The DNA polymorphic systems studied were demonstrated to be highly informative; their advantages and disadvantages were revealed. According to the data obtained, the genetic distances that were calculated from DNA fingerprints more adequately reflected the genetic relationships between the populations studied than the distances calculated from the allelic frequencies of four DNA loci. It was also found that, in population studies, it would suffice to analyze only the 3.5-6 kb fingerprint fragment that is most suitable for reading, rather than the entire fingerprint obtained.     

Evaluation of the relative contribution of Caucasoid and Mongoloid components in the formation of ethnic groups of the Volga-Ural region according to data of DNA polymorphism]

For the first time, an attempt was made to quantitatively estimate the relative contributions of major racial components to populations of the Volga-Ural region based on the data on allelic polymorphisms of nine loci of the mitochondrial and nuclear genomes. Comparison of the proportions of Caucasoid and Mongoloid characteristics in the gene pools of Bashkirs, Tatars, Chuvashes, Maris, Mordovians, Udmurts, and Komi revealed a heterogeneous pattern. Data on the proportions of major racial components in the nuclear genome indicated that the Caucasoid component was maximum in Mordovians, Komis, and Udmurts. Mongoloid characters were most prevalent in Bashkirs, Maris, Tatars, and Chuvashes. Data on restriction-deletion polymorphism of mitochondrial DNA (mtDNA) also indicated an increased Caucasoid contribution to Mordovian, Udmurt, and Komi gene pools and an increased Mongoloid component in Chuvashes and Tatars. In general, the results obtained agree with ethnic anthropological data indicating the greatest Caucasoid contribution to the Mordovian and Komi gene pools and an increased Mongoloid component in Turkic populations of the Volga-Ural region (Bashkirs, Tatars, and Chuvashes).     

Analysis of the genetic differentiation of Bashkirs and peoples from the Volgo-Ural region from data on polymorphic markers of the nuclear genome]

Nei's coefficient of genetic differentiation (Gst) was used to estimate the intergroup differentiation of four ethnic geographic groups of Bashkirs and the interethnic differentiation of seven ethnoses (Bashkirs, Tatars, Chuvashes, Udmurts, Maris, Komis, and Mordovians) from the Volga-Ural region. The coefficient of genetic differentiation calculated from data on four polymorphic loci (MET, D7S23, PKU, and apoB) and classical biochemical markers (AB0, MN, Rh, Hp, and AcP) of the nuclear genome was similar in all tested populations. The genetic difference between the ethnoses from the Volga-Ural region (Gst = 1.91%) was intermediate between that in European (Gst = 1.18%) and Siberian (Gst = 5.84%) ethnoses.     

VNTR Polymorphisms of the Serotonin Transporter and Dopamine Transporter Genes in Male Opiate Addicts

VNTR polymorphisms of the serotonin transporter (hSERT) and dopamine transporter (DAT1) gene were studied in male opiate addicts. Samples of ethnic Russians and ethnic Tatars did not differ in genotype and allele frequencies. Homozygosity at hSERT (especially 10/10) was associated with early opiate addiction, while genotype 12/10 proved to be protective. In the case of DAT1, genotype 9/9 was associated with early opiate addiction. The combination of hSERT genotype 10/10 with DAT1 genotype 10/10 was shown to be a risk factor of opiate abuse under 16 years of age.