Comparison of the effectiveness of solid nutrient medium in the in vitro cultivation of Neisseria gonorrhoeae isolates

Background. Neisseria gonorrhoeae is a facultatively anaerobic microorganism which is extremely demanding to the composition of a nutrient media and cultivation conditions. In a situation of the increasing shortage and cost of foreign components for the preparation of solid nutrient media, it is important to study the possibility of growing hard-to-cultivate microorganisms on domestically produced nutrient media.The aim of the study. To evaluate the growth of gonococcus colonies on two types of solid nutrient media – chocolate agar with growth and selective additives prepared using imported reagents and chocolate agar with growth additives manufactured by “Gem LTD” (Moscow, Russian Federation).Materials and methods. А reference strain of N. gonorrhoeae NCTC 12700/ ATCC 49226 and two types of chocolate agar (the first one – prepared in the State Scientific Center of Dermatovenerology and Cosmetology using imported components and the other one – from the domestic manufacturer “Gem LTD”) were used in the research.Results. The equivalence of the growth properties of both studied types of nutrient media when cultivating pure gonococcus was revealed.Conclusions. Ready-to-use chocolate agar with growth additives produced by “Gem LTD” can be successfully used in the laboratory for the cultivation of N. gonorrhoeae pure culture. Primary isolation of N. gonorrhoeae strains from clinical material is more appropriate to carry out on a medium that suppresses the growth of foreign microflora due to the inclusion of antibiotic additive. The organization of production of domestic bacteriological media for microorganisms with high nutrient requirements reduces the dependence of domestic microbiology on import and ensures their rapid delivery to laboratories

Comparative Analysis of the Sequenced Zaire ebolavirus Samples from the Republic of Guinea

An unprecedented on its scale Ebola fever epidemic, caused by Zaire ebolavirus, has been registered in the territory of West Africa in 2014-2015. The virus quickly spread from the Republic of Guinea into the neighboring countries. Presented are the results of comparative analysis between three Zaire ebolavirus genomes, the complementary DNA of which was obtained from the samples from Ebola fever patients in the Republic of Guinea in 2014. The nucleotide sequences of the genomes received have allowed for identification of phylogenetic affinity to certain references, displayed in the database of NCBI GenBank. General phylogenetic analysis by means of representative sampling has revealed two trends of genome evolutionary development from one and the same ancestral form. The first branch of evolution is represented by a relatively small number of Zaire ebolavirus isolates, disseminated in Guinea. The second one, the most numerous trend, is generated by four variants of Zaire ebolavirus genome, which have been identified starting from May - early June, 2014 in Sierra-Leone, but within a short period of time they have won the whole territory of the country and the neighboring Guinea and Liberia

Phenotypic and Molecular-Genetic Peculiarities of Yersinia pestis Strains from Trans-Baikal Steppe Plague Focus

The paper contains the data on the complex phenotypic and genotypic characteristics of Yersinia pestisstrains isolated in Trans-Baikal steppe plague focus before and after the succession of the main carrier which took place in the 1960s. Based on the PCR-analysis and multilocus sequence typing of glpD, melB, napA, rhaA, and iclR genes, encoding differentially significant properties such as glycerin, melibiose, rhamnose fermentation, isocitrate lyase production, and denitrification activity, developed are the proofs of affiliation of the studied strains to the biovariant antiqua of the plague agent main subspecies. Multilocus VNTR-analysis by seven locuses of variable tandem repeats – ms01, ms04, ms06, ms07, ms46, ms62 – has been used to establish genetic relations between the strains. Thus on the basis of the results obtained, it is established that the strains of the plague agent, isolated in the Trans-Baikal steppe focus in various periods of its existence, form one common branch on the phylogenetic tree of Y. pestis evolution

Polymorphism of ITS sequences in 35S rRNA genes in Elymus dahuricus aggregate species: two cryptic species?

Nuclear ribosomal internal transcribed spacer (ITS) sequences were sequenced for 23 species and subspecies of Elymus sensu lato collected in Russia. The Neighbor-Net analysis of ITS sequences suggested that there are four ribotypes called Core Northern St-rDNA, Core Southern St-rDNA, Northern dahuricus St-rDNA and Southern dahuricus St-rDNA. The Core Southern variant of St-rDNA is closely related to rDNA of diploid Pseudoroegneria stipifolia (PI 313960) and P. spicata (PI 547161). The Core Northern St-rDNA is closely related to rDNA of P. cognata (PI 531720), a diploid species of Kyrgyzstan carrying StY variant of the St genome. The Core Northern St-rDNA is widespread among the Elymus species of Siberia and the Far East, including Yakutia and Chukotka. The Core Southern St-ribotype is typical of southern Elymus and Pseudoroegneria of the South Caucasus, Primorye, Pakistan, and South Korea. The Northern dahuricus St-ribotype and Southern dahuricus St-ribotype are derivatives of the Core Northern and Core Southern St-ribotypes, correspondingly. Both of them were found in all four studied species of the E. dahuricus aggregate: E. dahuricus Turcz. ex Griseb., E. franchetii Kitag., E. excelsus Turcz. ex Griseb. and Himalayan E. tangutorum (Nevski) Hand.-Mazz. In other words, there are at least two population groups (two races) of the Elymus dahuricus aggregate species that consistently differ in their ITS-sequences in Siberia, the Far East and Northern China. Each contains all morphological forms, which taxonomists now attribute either to different species of E. dahuricus aggr. (E. dahuricus sensu stricto, E. franchetii, E. tangutorum, E. excelsus) or subspecies of Campeiostachys dahurica (Turcz. ex Griseb.) B.R. Baum, J.L. Yang et C.C. Yen. At the moment it is unknown if there are any morphological differences between plants carrying either Northern or Southern dahuricus rDNA. Probably, they are cryptic species, but it is certain that if differences in morphology between the two races exist, they are not associated with signs that are now considered taxonomically significant and are used to separate E. dahuricus s. s., E. franchetii, E. tangutorum, and E. excelsus

Phylogenetic Analysis of <i>Yersinia pestis</i> Strains of Medieval Biovar from Natural Plague Foci of the Russian Federation and Bordering Countries

Objective of the study is to conduct phylogenetic investigation of Yersinia pestis strains (medieval biovar) from plague foci of Russia and bordering countries, using SNP-analysis of the genome-wide sequences of these strains. Materials and methods. Carried out has been sequencing of 14 Y. pestis strains, medieval biovar, from 13 natural plague foci of Russia and neighboring states, as well as their comparison to 9 strains of the same biovar, contained in the NCBI GenBank database. Using software products - Wombac 2.0 and Bionumerics 7.1, revealed is the presence of 1875 core SNPs, on the basis of which a dendrogram of phylogenetic relations between medieval strains is constructed. Results and conclusions. In consequence of genome-wide SNP-analysis, it is established that Y. pestis strains, medieval biovar, from plague foci of Russia and bordering states are assigned to 2.MED1 phylogenetic line and fall under two major evolutionary branches, the first one of which includes strains from the Caucasus and Caspian-Sea regions, and the second one - from Central Asia and China. The data obtained can be used for the development of molecular-genetic methods for differentiation of Y. pestis strains, medieval biovar

Fast optical variability of SS 433

We study the optical variability of the peculiar Galactic source SS 433 using the observations made with the Russian Turkish 1.5-m telescope (RTT150). A simple technique which allows to obtain high-quality photometric measurements with 0.3-1 s time resolution using ordinary CCD is described in detail. Using the test observations of nonvariable stars, we show that the atmospheric turbulence introduces no significant distortions into the measured light curves. Therefore, the data obtained in this way are well suited for studying the aperiodic variability of various objects. The large amount of SS 433 optical light curve measurements obtained in this way allowed us to obtain the power spectra of its flux variability with a record sensitivity up to frequencies of ~0.5 Hz and to detect its break at frequency =~2.4e-3 Hz. We suggest that this break in the power spectrum results from the smoothing of the optical flux variability due to a finite size of the emitting region. Based on our measurement of the break frequency in the power spectrum, we estimated the size of the accretion-disk photosphere as 2e12 cm. We show that the amplitude of the variability in SS 433 decreases sharply during accretion-disk eclipses, but it does not disappear completely. This suggests that the size of the variable optical emission source is comparable to that of the normal star whose size is therefore R_O \approx 2e12 cm \approx 30 R_sun. The decrease in flux variability amplitude during eclipses suggests the presence of a nonvariable optical emission component with a magnitude m_R=~13.2.Comment: 12 pages, 11 figures. Accepted for publication in Astronomy Letters. The original version in Russian is available at http://hea.iki.rssi.ru/rtt150/ru/ss433_pazh10/pss433_fast.pd

Updating of Intra-Specific <i>Yersinia pestis</i> Classification, Based on the Results of Whole-Genome Sequencing of the Strains from the Russian Federation and the Neighboring States

Carried out has been genome-wide sequencing of 20 Yersinia pestis strains from all 11 natural plague foci in Russia and some foci in the neighboring states. Phylogenetic analysis on the basis of 1918 core SNPs, identified in the genomes of these strains and 16 Y. pestis strains from NCBI GenBank, has revealed 5 clusters of closely related strains. Taking these clusters into account, up-dated has been subspecific classification of plague agent. New taxonomy has combined 5 subspecies: major (ssp. pestis ), Caucasian (ssp. caucasica ), ulegeisk (ssp. ulegeica ), and two novel ones - Central Asian (ssp. central asiatica ) and Angolan (ssp. angola ). Central Asian subspecie comprises evolutionally related strains, earlier classified as altaica and hissarica, as well as the strains from Talas high-mountain focus in Kirghizia and Uzbekistan, and microtus strains from China. Central asiatica is divided into three biovars - altai, hissar, and microtus. Set forward is a serviceable designation for the strains: 0.PE4a - for altai ones, 0.PE4h - for hissar, 0.PE4t - for talas, and 0.PE4m - for microtus, and also for ulegeica subspecie - 0.PE5

Фракционное плавление с использованием теплового насоса

Feasibility study of the fractional smelting continuum process by the means of a calorific pump with a closed cycle on the working substance is provided in this article. It is shown that the usage of the calorific pump allows decreasing significantly power inputs for realization of the studied process.Выполнен анализ эффективности использования парокомпрессионного теплового насоса с замкнутым циклом по рабочему телу в процессе непрерывного фракционного плавления. Показано, что применение теплового насоса позволяет снизить энергетические затраты на проведение рассматриваемого процесс