Analysis of the Diversity and Functional Potential of Bacterial Communities in Tuberculomas.

The dynamics of lung microbiota in tuberculosis remains poorly understood. Sequencing of variable regions of the 16S rRNA gene from surgically excised tuberculosis foci and biopsy specimens of normal lung tissue allowed characterization of the diversity and predictive potential of bacterial communities. Taxonomic diversity indices attested to differences in the structure of microbial communities between "healthy" lungs and tuberculomas. The microbial composition of "healthy" lungs varied in taxonomic diversity and was presented by both gram-positive and gram-negative bacteria with sufficiently similar metabolic potential. The microbiota of the examined tuberculomas consisted of Mycobacterium tuberculosis in 99.9% of cases. A significant part of the metabolic pathways predicted by PICRUSt2 included cholesterol catabolism, sulfate assimilation, and various pathways for the biosynthesis of cell wall components.

Online Service with Automated Interpretation of Sequencing Data and Prediction of Pyrazinamide Resistance in Mycobacterium tuberculosis.

Pyrazinamide plays an important role in the treatment of tuberculosis. However, the microbiological test for pyrazinamide resistance is more complex and less reliable than testing of susceptibility to other anti-tuberculosis drugs due to the need to grow the pathogen at pH 5.5. Identification of mutations that cause resistance to anti-tuberculosis drugs can replace microbiological methods. Mutations in the pncA gene are responsible for the main mechanism of the resistance to pyrazinamide and are found in more than 90% of resistant strains. However, the genetic method for determining drug susceptibility is very complex, because mutations leading to pyrazinamide resistance are diverse and scattered throughout the gene. We have developed a software package for automatic data interpretation and prediction of the resistance to pyrazinamide based on Sanger sequencing results. The effectiveness of detection of pyrazinamide resistance in 16 clinical samples was compared using the BACTEC MGIT 960 automated system and pncA gene Sanger sequencing with automated analysis of the results. A significant advantage of the developed method over a single microbiological study was shown, due to greater reliability of the results irrespective of the purity of isolates.

Proteomic characterization of Mycoplasma gallisepticum nanoforming.

The goal of this work was to create a model for the long persistence of Mycoplasma gallisepticum in depleted medium and under low growth temperature followed by proteomic study of the model. Nanoforms and revertants for M. gallisepticum were obtained. Proteomic maps were produced for different stages of the formation of nanoforms and revertants. It is shown that proteins responsible for essential cellular processes of glycolysis, translation elongation, and DnaK chaperone involved in the stabilization of newly synthesized proteins are crucial for the reversion of M. gallisepticum to a vegetative form. Based on the current data, it is assumed that changes in the metabolism of M. gallisepticum during nanoforming are not post-mortal, thus M. gallisepticum does not transform to uncultivable form, but remains in a reversible dormant state during prolonged unfavorable conditions.

[Coding nucleotide sequences of tick-borne encephalitis virus strains isolated from human blood without clinical symptoms of infection].

Genomes of four tick-borne encephalitis virus strains, isolated from the blood of the individuals after tick bites and causing no clinical symptoms of infection, were characterized. Analysis of translated polypeptides revealed 21 amino acid positions typical of this group of strains and distinguishing them from the other tickborne encephalitis virus strains of Far Eastern subtype examined earlier. Only three mutations led to substantial amino acid changes, which probably could affect the infection process severity. It is suggested that two associated mutations, deletion of amino acid 111 in the capsid protein C and substitution (Ser1534 --> Phe) in the NS3 protein influence strictly coordinated polyprotein processing, disturbing correct arrangement of viral particles. This process can result in the development of defect viral particles, containing no RNA. Mutation (Ser917 --> Gly) in nonstructural protein NS1 results in the substitution of hydrophilic amino acid, specific to highly virulent strains, by the hydrophobic one. This could influence the effectiveness of viral replication complex, thereby affecting the infectivity of tick-borne encephalitis virus strains.

[Molecular-genetic comparison of morbilliviruses which caused epizooty in Baikal (Phoca siberica) and Caspian (Phoca caspica) seals]. / Molekuliarno-geneticheskoe sravnenie morbillivirusov, vyzvavshikh épizootii baikal'skikh (Phoca sibirica) i kaspiiskikh (Phoca caspica) tiulenei.

The nucleotide sequences were determined for a phosphoprotein gene fragment of canine distemper virus (CDV) by using the RT-PCR method with the subsequent sequencing of amplicons from total RNA isolated from 2 samples of Caspian seals, 15 samples of Baikal seals and from samples of dog's and sea-lion's brains. The above materials were phylogenetically analyzed. The heterogeneity of the virus circulating in the Baikal-seal population was demonstrated. Morbillivirus, that caused epizooty in Caspian seals, was shown to be a CDV variant, whose phosphoprotein gene structure was not different, within the analyzed stretch, from the corresponding gene of the most widespread variant of the Baikal seal virus. The data obtained suggest that morbillivirus could be transmitted by birds during their seasonal migrations.