[Comparative results of preimplantation genetic screening by array comparative genomic hybridization and new-generation sequencing].

Aneuploidies as quantitative chromosome abnormalities are a main cause of failed development of morphologically normal embryos, implantation failures, and early reproductive losses. Preimplantation genetic screening (PGS) allows a preselection of embryos with a normal karyotype, thus increasing the implantation rate and reducing the frequency of early pregnancy loss after IVF. Modern PGS technologies are based on a genome-wide analysis of the embryo. The first pilot study in Russia was performed to assess the possibility of using semiconductor new-generation sequencing (NGS) as a PGS method. NGS data were collected for 38 biopsied embryos and compared with the data from array comparative genomic hybridization (array-CGH). The concordance between the NGS and array-CGH data was 94.8%. Two samples showed the karyotype 47,XXY by array-CGH and a normal karyotype by NGS. The discrepancies may be explained by loss of efficiency of array-CGH amplicon labeling.

[AlkB homologues in thermophilic bacteria of the genus Geobacillus].

Screening of alkane hydroxylase genes (alkB) was performed in the thermophilic aerobic bacteria of the genus Geobacillus. Total DNA was extracted from the biomass of 11 strains grown on the mixture of saturated C10-C20 hydrocarbons, PCR amplification of fragments of alkB genes was performed with degenerate oligonucleotide primers, PCR products were cloned and sequenced. For the first time in the genome of thermophilic bacteria the presence of a set of alkB gene homologues was revealed. The strains each contain three to six homologues among which only two are universal for all of the strains. Comparative phylogenetic analysis of the nucleotide sequences and the inferred amino acid sequences showed close relatedness of six of the revealed variants of geobacilli sequences to the alkB4, alkB3, and alkB2 genes that had previously been revealed by other authors in Rhodococcus erythropolis strains NRRL B-16531 and Q15. The rest two variants of alkB sequences were unique. Analysis of the GC composition of all the Geobacillus alkB homologues revealed closer proximity to the rhodococcal chromosomal DNA than to the chromosomal DNA of geobacilli. This may be an indication of the introduction of the alkB genes into the Geobacillus genome by interspecies horizontal transfer; and rhodococci or other representatives of the Actinobacteria phylum were probably the donors of these genes. Analysis of the codon usage in fragments of alkB genes confirms the suggestion that the pool of these genes is common to the majority of Gram-positive and certain Gram-negative bacteria. Formation of a set of several alkB homologues in a genome of a particular microorganism may result from free gene exchange within this pool.

[A method of genotyping clinical isolates of Ureaplasma urealyticum biovar Parvo]. / Metod genotipirovaniia klinicheskikh izoliatov Ureaplasma urealyticum biovara Parvo.

A new method for typing clinical isolates of U. urealyticum (Parvo biovar) is based on SSCP analysis of amplicons of mba gene 5' region and upstream region. The mba gene is coding for MB gene of U. urealyticum. This method allows genotyping of U. urealyticum isolates using vaginal and cervical swabs without culturing. Sixty-two clinical specimens from patients with a history of chronic cystitis, chronic pyelonephritis, chronic salpingo-oophoritis, erosion of the cervix uteri, and spontaneous abortions were tested for U. urealyticum. The bacterium was detected in 64% (40 specimens), 83% (33) of which belonged to Parvo biovar. Parvo biovar isolates were analyzed and genotyped as follows: first genotype 52%, second genotype 33%, and third genotype 16%. Further sequencing of the first and second genotype amplicons showed that the first genotype belonged to serotype 3 and second genotype to serotype 6.