PubMed Health⌕ Search

Biomedical subjects

S A Bulat

Publications and source records attributed to S A Bulat.

At least 19 recordsLinked to original sources
PubMed2004

Phylogenetic relationship of Fusarium langsethiae to Fusarium poae and Fusarium sporotrichioides as inferred by IGS, ITS, beta-tubulin sequences and UP-PCR hybridization analysis.

Fusarium langsethiae was recently described to accommodate "powdery" isolates of Fusarium poae, which morphologically resemble F. poae, but whose metabolite profile is similar to that of Fusarium sporotrichioides. In order to investigate the phylogenetic relationship of F. langsethiae to closely related species, we sequenced the internal transcribed spacer (ITS) regions 1 and 2 and part of the intergenic spacer (IGS) region of the rDNA cluster and part of the beta-tubulin gene from 109 strains of F. poae, F. sporotrichioides, F. langsethiae and Fusarium kyushuense from different geographic origin. Sequence analysis of ITS1 and 2 was unable to separate all F. sporotrichioides strains from F. langsethiae strains. Sequence analysis of beta-tubulin distinguished all four species, but it did not resolve the phylogenetic relationship between these two species. Sequence analysis of the IGS region distinguished the four species and led to a higher number of subgroups of the individual species, of which that of F. sporotrichioides var. minus isolates was even better supported than that of F. poae and F. langsethiae. Neighbor-joining and POY analyses of all combined sequences reliably separated all species studied, including F. langsethiae, clearly from F. sporotrichioides. The high intraspecific variability of the IGS sequences were found useful to group isolates according to their geographic origin. These results are in accordance with the results of the UP-PCR hybridization analysis. In summary, our data offer molecular support for the description of F. langsethiae as a new species in section Sporotrichiella.

Base Sequence↗
PubMed2004

Evolutionary relationships within 'pygmaeus' group microphallids using genetic analysis and scanning electron microscopy.

There are four species of 'pygmaeus' microphallids, namely Microphallus pygmaeus, M. piriformes, M. pseudopygmaeus and M. triangulatus (Trematoda: Microphallidae) which are parasites of marine birds and their sporocysts give rise to transmissible metacercariae inside littoral gastropods (mostly littorines). Universally primed polymerase chain reaction (UP-PCR) showed no apparent pattern between genetic diversity of the metacercariae as estimated by genomic banding profiles and their geographic region or molluscan host species. At the same time UP-PCR product cross-hybridization showed that M. pseudopygmaeus and M. triangulatus are genetically very similar, indicating that these taxa represent one species complex. In contrast, M. pygmaeus and M. piriformes are genetically well separated from each other and also from the pseudopygmaeus-triangulatus complex. Scanning electron microscopy of ventral spines, and analyses of spine angles and the number of teeth per spine, showed that all species differed significantly from one another. It was concluded that M. piriformes represents the original western member of the 'pygmaeus' group. Microphallus pygmaeus probably diverged from M. piriformes as it progressively specialized for sea duck final hosts. Microphallus pseudopygmaeus and M. triangulatus diverged from each other and the piriformes-pygmaeus ancestral line relatively recently. Microphallus pseudopygmaeus specialized for adoption of a wide range of gastropod host species and M. triangulatus developed morpho-functional specialization associated with final host exploitation.

Animals↗
PubMed2003

Differentiation of six sibling species in the Saccharomyces sensu stricto complex by multilocus enzyme electrophoresis and UP-PCR analysis.

UP-PCR analysis and multilocus enzyme electrophoresis were used to characterize 37 strains of the sibling species Saccharomyces cerevisiae, S. bayanus, S. cariocanus, S. kudriavzevii, S. mikatae and S. paradoxus. The results demonstrate that both molecular approaches are useful for discriminating between these phenotypically indistinguishable Saccharomyces species. The data obtained are in excellent agreement with previously reported genetic analyses, sequencing of the 18S rRNA and ITS regions, and DNA-DNA reassociation data.

DNA, Fungal↗
PubMed2000

Intraspecific variation in gamma-radiation resistance and genomic structure in the filamentous fungus Alternaria alternata: a case study of strains inhabiting Chernobyl reactor no. 4.

This is probably the first report on intraspecific variation in radiation resistance for filamentous fungi. It was revealed that natural ("field") strains of the filamentous fungus Alternaria alternata are extremely variable in response to gamma-irradiation ranging from supersensitive to highly resistant to radiation. At the same time nearly all strains originating from the highly radiation-polluted reactor of the Chernobyl (Ukraine) Nuclear Power Plant possessed high radiation resistance. The genome structure of strains studied by universally primed polymerase chain reaction (UP-PCR) was found to be well conserved in "reactor" but not in "control" strains. The "reactor" strains appear to be genetically adapted to this high radiation habitat by means of selection, thus providing a natural source of genetically homogeneous fungal lineages.

Alternaria↗
PubMed2000

Identification of a universally primed-PCR-derived sequence-characterized amplified region marker for an antagonistic strain of Clonostachys rosea and development of a strain-specific PCR detection assay.

We developed a PCR detection method that selectively recognizes a single biological control agent and demonstrated that universally primed PCR (UP-PCR) can identify strain-specific markers. Antagonistic strains of Clonostachys rosea (syn. Gliocladium roseum) were screened by UP-PCR, and a strain-specific marker was identified for strain GR5. No significant sequence homology was found between this marker and any other sequences in the databases. Southern blot analysis of the PCR product revealed that the marker represented a single-copy sequence specific for strain GR5. The marker was converted into a sequence-characterized amplified region (SCAR), and a specific PCR primer pair was designed. Eighty-two strains, isolated primarily from Danish soils, and 31 soil samples, originating from different localities, were tested, and this specificity was confirmed. Two strains responded to the SCAR primers under suboptimal PCR conditions, and the amplified sequences from these strains were similar, but not identical, to the GR5 marker. Soil assays in which total DNA was extracted from GR5-infested and noninoculated field soils showed that the SCAR primers could detect GR5 in a pool of mixed DNA and that no other soil microorganisms present contained sequences amplified by the primers. The assay developed will be useful for monitoring biological control agents released into natural field soil.

DNA Primers↗
PubMed1995

[Genetic structure of soil population of the fungus Fusarium oxysporum Schlechtend.: Fr.: molecular reidentification of the species and genetic differentiation of isolates using polymerase chain reaction with universal primers (UP-PCR)].

The genetic structure of three soil populations of fungus Fusarium oxysporum was analyzed using polymerase chain reaction with universal primers (UP-PCR). Distinct UP-PCR variants revealed by means of cross-dot hybridization of amplified DNA and restriction analysis of nuclear ribosomal DNA represent subspecies or sibling species of F. oxysporum. The remaining isolates of F. oxysporum showed moderate UP-PCR polymorphism characterized by numerous types, whose relatedness was analyzed by computer treatment of the UP-PCR patterns. The genetic distance trees based on the UP-PCR patterns, which were obtained with different universal primers, demonstrated similar topology. This suggests that evolutionarily important genome rearrangements correlatively occur within the entire genome. Isolates representing different UP-PCR polymorphisms were encountered in all populations, being distributed asymmetrically in two of these. In general, soil populations of F. oxysporum were represented by numerous genetically isolated groups with a similar genome structure. The genetic heterogeneity of the isolates within these groups is likely to be caused by the parasexual process. The usefulness of the UP-PCR technique for population studies of F. oxysporum was demonstrated.

Base Sequence↗
PubMed1993

[The production of clones of "man x Chinese hamster" hybrid cells containing different parts of the human genome].

Some approach has been described to create hybrid cell lines (human x Chinese hamster) which contain different parts of human genome, and then efficiently to reveal and isolate the human DNA from these. This method involves the introduction of a selective marker in different sites of the human cell genome, by transfecting them with plasmid SV2neo, and the use of flow cytometry and DNA polymerase chain reaction with primers specific only for human DNA.

Animals↗
PubMed1993

[The detection of human DNA in cell hybrids by the polymerase chain reaction with universal primers: the species specificity of the amplified DNA].

The human DNA detection method is developed on the basis of DNA cross-hydridization of the amplification products obtained by the universally primed polymerase chain reaction (UP-PCR) technique. These PCR products are characterized by species-specificity in hybridization assay. Two somatic cell hybrids "human x Chinese hamster" supposed to contain the human DNA, according to selection procedure, were analysed by this method. As a result, the presence of human DNA, unable to be tested by cytological techniques, have been proven. The amplified human DNA can be mapped by this method.

Animals↗
PubMed1992

Comparative analysis of spontaneous mitotic recombination in [cir0] and [cir+] strains of the yeast Saccharomyces cerevisiae.

The influence of the 2 microns plasmid on homologous recombination in the right arm of chromosome XV of the yeast Saccharomyces cerevisiae has been examined. No differences between spontaneous mitotic recombination rates in [cir0] and [cir+] derivatives of two yeast diploid tester strains were detected. In the course of analysis an unusually high coincident conversion frequency at ADE2, HIS3, and two RFLP loci adjacent to ADE2, was observed. The character of coincident homozygotization of linked markers argues for a "break-and-replicate" mechanism underlying the coincident conversion events.

DNA, Fungal↗
PubMed1992

[Polymerase chain reaction with universal primers for studying genomes].

Universal primer ability of generating conservative and variable UP-PCR (universally primed polymerase chain reaction) species-specific patterns was analysed on bacteria to serve as an example. Also, two important properties of the UP-PCR patterns (species/primer DNA hybridization specificity) are characterized.

Base Sequence↗
PubMed1991

[The gene identification of bacterial species and serovariants by the polymerase chain reaction with universal oligonucleotides: the reidentification of earlier isolated strains of Yersinia pseudotuberculosis].

Genetic analysis of 19 standard strains belonging to 6 Yersinia species (Y. pestis, Y. pseudotuberculosis, Y. enterocolitica, Y. kirstensenii, Y. frederiksenii, Y. intermedia) revealed that gene typing by the method of polymerase chain reaction (PCR) with the use of universal primers permitted the identification of species in bacterial cultures by PCR patterns and the determination of Y. pseudotuberculosis serovars within 4 hours. By this method 23 Y. pseudotuberculosis strains (serovar 1), earlier isolated in different regions of the USSR from humans and rodents, were studied. The study showed that out of 14 strains of human origin only two strains could actually be classified with serovar 1, while the remaining strains were reidentified as belonging to serovar 5. Among 9 strains isolated from rodents those of serovar 1 prevailed (8 strains). The authors suppose that strains of serovar 5 cause outbreaks and sporadic cases of pseudotuberculosis, occurring considerably more often than it is commonly believed in the USSR.

Animals↗
PubMed1987

[Saccharomyces cerevisiae mutants characterized by increased induced mutagenesis. II. Genetic analysis of mutants].

Induction of forward adenine-dependent (Ade+----Ade-) mutations by HAP was used to analyse genetically yeast mutants with enhanced induced mutagenesis. Three mutations studied in detail segregated as a single mendelian trait and composed independent complementation groups (HIM1, HIM2, HIM3). the him1-1 mutation was centromere-linked, the him3-1 and him2-1 mutations being not. All three mutations did not show any cross-linkage. Uracil-DNA glycosylase activity was determined in crude cell extract from wild type strain and him mutants; no detectable differences were observed.

Adenine↗
PubMed1987

[Genetic study of plasmid integration into yeast chromosomes. V. Mapping of integration sites for the plasmid pYF91].

The data on mapping the episomal plasmid integration sites in yeast chromosomes I, III, IV, V, VII, XV are presented. In addition to the integration site at leu2 of chromosome III localized earlier, 6 more loci containing apparently the homologous yeast transposons, with a copy in a plasmid, were defined. The fact of plasmid integration was proved by colony hybridization technique with the pBR322 probe. The plasmid DNA segregation (the ratio 2:2) and its linkage to pLEU2 plasmid marker gene were observed in hybrids of all integrants studied.

Chromosome Mapping↗
PubMed1987

[Genetic study of plasmid integration into yeast chromosomes. VI. Patterns of the destabilization of chimeric chromosomes and their use in gene mapping].

The 2 microns DNA-dependent destabilization of yeast chimeric chromosomes III, IV, V was analysed. The comparison of its peculiarities with the earlier localized sites of episomal plasmid integration allowed to derive genetic regularities of destabilization process. Two destabilization rules that describe patterns of the loss of genetic information in the chromosome were formulated. The usefulness of this for mitotic intrachromosomal gene mapping in yeast was demonstrated using plasmid integration site mapping in chromosome I.

Chimera↗
PubMed1987

[Genetic study of plasmid integration into yeast chromosomes. III. Selection for a phenotype of Saccharomyces cerevisiae (Meyen ex Hansen) clones which lost the 2-micron DNA and their genetic testing].

We used the coloured adeI (cir+) haploid strain containing an episomal plasmid integrated into the chromosome I for visual detection and genetic testing of Saccharomyces cerevisiae clones having lost 2 microns DNA. During incubation, colonies of this strain were covered with numerous papillae of the same genotype. Stable clones which did not generate such papillae were isolated. Hybrids of these clones with (cir0) partner were not shown to exhibit destabilization of the chimeric chromosome. The stable clones isolated proved to lack 2 microns DNA, as shown by colony hybridization technique. We conclude therefore that the loss of the cryptic yeast plasmid may be phenotypically detected.

Chromosome Deletion↗
PubMed1987

[Genetic study of plasmid integration into yeast chromosomes. IV. Integration of the plasmid pYF91 into different yeast chromosomes].

Integration of the episomic chimeric plasmid pYF91 into yeast chromosomes has been studied. Plasmid insertion into the chromosomes was observed to occur with the frequency of 4 X 10(-8). 379 integrants were selected from the highly unstable (cir0) transformants. The fact of plasmid integration into particular chromosomes was confirmed for 318 integrants. Genetic analysis showed that the plasmid can integrate into the region of LEU2 gene or into another arm of chromosome III (227 integrants), and also into other chromosomes: I, II, IV, V, VI, VII, VIII, IX, XII, XV (91 integrants). It is suggested that integration is the result of recombination between yeast chromosomes and homologous plasmid regions carrying LEU2 gene or Ty element and "delta" sequence.

DNA, Fungal↗
PubMedDate not supplied

Comparison of some molecular-genetic techniques for identification of Leishmania circulating in natural foci of zoonotic cutaneous leishmaniasis in the central Asia region.

Different molecular-genetic methods were used to identify a cohort of Leishmania strains from natural foci of zoonotic cutaneous leishmaniasis located in Central Asia, on the former USSR territory. The results obtained using isoenzymes, PCR, restriction fragment length polymorphisms of kDNA and molecular hybridization techniques are discussed in terms of their applicability, discrimination power and feasibility for answering questions related to molecular epidemiological research and for detecting mixed Leishmania infections.

Animals↗