[Imperfect and Compound Microsatellites in the Genomes of Burkholderia pseudomallei Strains].

Evolution of microsatellites (or simple sequence repeats, SSRs) is a complex process that converts perfect repeats to novel structural elements with functions poorly understood, such as imperfect and compound microsatellites. An in silico analysis often Burkholderia pseudomallei genomes revealed 215683 micro-satellites, and more than 98% of them proved imperfect. The density of microsatellites in the genome ranged from 2922.7 to 3022.6 per Mbp. Approximately 10.20-10.67% of the repeats were parts of compound micro-satellites. The of compound microsatellite density varied from 144.7 to 150.6 per Mbp. Between-strain differences in microsatellite distribution were explained by a direct correlation of the SSR density with the GC content and an inverse relationship between the SSR density and the genome size. For each B. pseudomallei chromosome, the SSR density similarly correlated with its size and GC content. Chromosome 2 showed a significant correlation between the SSR and compound microsatellite densities (r = 0.93, p < 10^(-3)). The association of imperfect and compound microsatellite densities with the structural features of each chromosome and the fact that motifs are degenerate and occur in few copies in the majority of B. pseudomallei microsatellites agree with the previous hypothesis of negative selection affecting extended SSRs. The mechanism of selection possibly involves an accumulation of point mutations, which lead to an interruption of the repeat during replication because easily passable secondary structures may form to stabilize the microsatellite length.

[The development and application of reagents kit for detection RNA of the causative agents of melioidosis and glanders by transcription-based amplification (NASBA) in real-time.]

The polymorphism of clinical manifestations of melioidosis and glanders and their high mortality require improvement of diagnostics for detection of this agents. The perspectivity of development of transcription-based amplification real-time NASBA diagnostic kits is determined by high analytical sensitivity and the opportunity to perfom the verification of the results of other methods for pathogenic Burkholderia species detection. The fragment of 23S rRNA gene was selected as the target for development of real-time NASBA kit. The high specificity of the constructed oligonucleotides was confirmed during the analysis of wide range of heterological strains of microorganisms and sequencing of amplified fragments of 23S rRNA gene. The analytical sensitivity of the developed kit allowed to detect Burkholderia pseudomallei and Burkholderia mallei in concentration of 1×101 microbial cells per ml. The high functional characteristics of developed kit as well as the possibility to use it in case of appereance of discordant result during the detection of pathogenic Burkholderia species were demonstrated while studying biological samples.