[Phenotypic manifestation and trans-conversion of primary genetic material damages considered in the alpha-test on the yeast Saccharomyces cerevisiae].

Primary (spontaneous and externally induces) damages to genetic material frequently lead to heritable changes (gene mutations, chromosome aberrations and nondisjunction), which may cause cancer inherent and inborn diseases. It is suggested that primary damages may affect a phenotype until they are repaired or become mutations during inaccurate repair The alpha-test on the yeast Saccharomyces cerevisiae can answer the fundamental questions as the nature of primary damages that can be phenotypically manifested, their occurrence, conversion to each other and repair or conversion to heritable changes in genetic material.

[Genetic heterogeneity of Borrelia afzelii in the natural focus of the Middle Urals].

As shown by sequencing the spacer rrf (5S)--rrl (23S) in 72 isolates of B. afzelii (one of the causative agents of Ixodes tick borne Borrelia infections) and the chromosomal gene coding protein P66 in 22 isolates, that in the natural focus located in the Middle Urals two different genetic subgroups (VS461 and NT28) of this genospecies simultaneously circulate. These subgroups are represented by 5 gene variants (rrf) 5S--(rrl) 23S and 5 allelic variants in gene p66. The latter, similarly to spacer gene variants, are not linked with a definite host and occur in different rrf--rrl variants of the infective agent. At the same time the definite species of vectors and carriers may be the host of several different B. afzelii variants, both in the spacer and in the gene coding protein P66, which maintains the genetic heterogeneity of B. afzelii population in the natural focus.

[Allele variants of Borrelia afzelii found by sequencing of the chromosome gene p66].

Sequencing of gene p66 fragments of 246-337 p.b. was performed in 45 isolates of Aorrelia afzelii isolated from different transmitting agents and reservoir hosts within the habitation area of the spirochaeta. At least seven allele variants of the pathogenic agent were found indifferent natural foci of the disease. The extent of similarity between the nucleotide sequences of the isolates of the same allele variant was 99.9-100%; the extent of similarity between different allele variants was 98.9-99.7%. It was found that the majority of genovariants of A. afzelii (with respect to 5S-23S) incorporated several different allele variants of gene p66, all allele variants being found in the two genogroups (VS461 and NT28) of the pathogenic agent.

[A study of possible transovarial and transphase transmission of borreliae by the tick Dermacentor reticulatus (Ixodidae)].

A study of possible transovarial and transphase transmission of borreliae by the tick Dermacentor reticulatus is carried out. The possibility of borreliae transmission by the ticks of this species being infected spontaneously as well as experimentally is shown in principle. Although borreliae are preserved in the organism of D. reticulatus, low values of the infestation are established in the different stages of D. reticulatus development and in all steps of the study. D. reticulatus may be involved in the process of borreliae circulation in natural foci of tick-born borreliosis, but this species has no a significant importance for the maintenance of it.

[Genetic characterization of pathogenic Borrelia, group A14S, isolated in Ukraine].

Borrelia Ir-5215, isolated from ticks Ixodes ricinus in Ukraine (the Crimean autonomous region), was identified by the method of the polymorphism of the fragment length of the restriction amplicon of rRNA spacer region 5S-23S. Its Msel-restriction profile was relatively similar to that of B. afzelii. The sequencing of spacer region rrf (5S)-rrl (23S) and 16S rRNA gene, as well as the analysis of the similarity of nucleotide sequences, obtained in the course of these study, revealed the differences between Borrelia sp, lr-5215 and six European species of Borrelia burgdorferi sensu lato and a high level of similarity (more than 95.1% for 5S-23S rRNA and 99.4% for 16S rRNA gene) to three known representatives of genome group A14S (Borrelia spp. A14S, I-77 and PC-Rq17). This suggests that isolated Borrelia lr-5215 is a new representative of pathogenic B. burgdorferi sensu lato genome group A14S, which is spread, together with Central Europe, also in southern Ukraine.

[Preparations for serodiagnosis of diseases due to causative agents of ixodes tick-borne borreliosis (Lyme disease). Communication 3. Comparative study of enzyme immunoassay test-systems for detection of IgM to Borrelia burgdorferi sensu lato]. / Preparaty dlia serodiagnostiki zabolevanii, vyzyvaemykh vozbuditeliami iksodovykh kleshchevykh borreliozov (bolezn' Laima). Soobshchenie 3. Sravnitel'noe izuchenie immunofermentnykh test-sistem, ispol'zuemykh dlia vyiavlenia IgM k Borrelia burgdorferi sensu lato.

Three foreign and one Russian ELISA test-systems for detection of IgM to Borrelia burgdorferi sensu lato were comparatively studied with the use of the clinical material in an encoded experiment. In the foreign ELISA test-systems based on the use of native antigens of borrelia, cross reactions with sera from patients with syphilis, Epstein-Barr infection, cytomegalovirus infection and systemic lupus erythematosus were detected. The Russian recombinant ELISA test-system Borreliosis-ELISA-IgM showed high sensitivity and specificity. The simultaneous use of the test-systems for detecting IgG and IgM significantly increased the efficacy of diagnosis of early borreliosis.

[New phenotypic manifestation of the ad2 mutation in Saccharomyces cerevisiae yeast--the inability to grow on a synthetic medium with glycerol and hypoxanthine]. / Novoe fenotipicheskoe proiavlenie mutatsii ade2 drozhzhei Saccharomyces cerevisiae--nesposobnost' rasti na sinteticheskoi srede s glitserinom i gipoksantinom.

The ADE2 gene of Saccharomyces cerevisiae yeast encodes aminoimidazole ribonucleotide-carboxylase (AIR-carboxylase), an enzyme catalyzing the sixth stage of purine nucleotide biosynthesis. Strains bearing the ade2 mutation are able to grow on a glucose-containing synthetic medium with the addition of adenine or hypoxanthine, which under the action of the cellular phosphoribosyltransferases are converted into adenosine monophosphate and inosine monophosphate, respectively. Our studies showed that ade2 mutants were unable to grow on a synthetic medium with glycerol and hypoxanthine. This newly described feature is not constitutively manifested, because some strains can contain suppressor mutations which restore the ability to grow on a synthetic medium with glycerol and hypoxanthine. The ade4, ade5, ade8, ade6, and ade7 mutations were found to suppress the phenotypic manifestation of the ade2 mutations via inactivation of enzymes catalyzing the first, second, third, fourth and fifth stages of purine biosynthesis, while the ade1 mutation, which inactivates enzyme of the seventh stage, lacks suppressive activity. Strains with single adenine mutations, ade4, ade5, ade8, ade6, ade7, or ade1 grow on glycerol- and hypoxanthine-containing media. Our data suggest that the new property of the ade2 mutations could be associated with the accumulation of the AIR-carbole-ribonucleotide. A mutation resulting in the requirement for serine on the medium with glycerol, but not glucose, is described.

[Saccharomyces cerevisiae ADE12 gene, coding for adenylosuccinate synthetase (EC 6.3.4.4). Cloning, sequencing, expression, and superproduction]. / Gen ADE12 drozhzhei Saccharomyces cerevisiae, kodiruiushchii adenilosuktsii-sintetazu (KF 6.3.4.4). Klonirovanie, sekvenirovanie, izuchenie ékspressii, superproduktsiia.

The cloning and sequencing of Saccharomyces cerevisiae ADE12 gene encoding the structure of adenylsuccinate synthetase (ASS) are reported for the first time. Comparative analysis of all known ASS sequences was carried out. Regulation of ADE12 gene expression by exogenic adenine was carried out. The properties of ASS which was isolated and purified from overproducing yeast strain were examined.