Invariants of pseudogroup actions: Homological methods and Finiteness theorem

We study the equivalence problem of submanifolds with respect to a transitive pseudogroup action. The corresponding differential invariants are determined via formal theory and lead to the notions of k-variants and k-covariants, even in the case of non-integrable pseudogroup. Their calculation is based on the cohomological machinery: We introduce a complex for covariants, define their cohomology and prove the finiteness theorem. This implies the well-known Lie-Tresse theorem about differential invariants. We also generalize this theorem to the case of pseudogroup action on differential equations.Comment: v2: some remarks and references addee

SDiff(2) and uniqueness of the Pleba\'{n}ski equation

The group of area preserving diffeomorphisms showed importance in the problems of self-dual gravity and integrability theory. We discuss how representations of this infinite-dimensional Lie group can arise in mathematical physics from pure local considerations. Then using Lie algebra extensions and cohomology we derive the second Pleba\'{n}ski equation and its geometry. We do not use K\"ahler or other additional structures but obtain the equation solely from the geometry of area preserving transformations group. We conclude that the Pleba\'{n}ski equation is Lie remarkable

Development of Criteria for Probiotic Bacteria Selection for Broadening the Spectrum of Available Anti-Cholera Drugs

Studied is the anti-cholera activity of 40 strains from different species of probiotic bacteria according to the main qualitative characteristics, which are determined on the basis of quantitative data. Established are the selection criteria for probiotic bacteria to be used for cholera treatment: antagonistic activity against V. cholerae – high or moderate, adhesion – only moderate, acid forming activity – high or moderate. The preventive and medical efficiency of 5 selected strains of lactobacilli and 1 strain of bifidobacterium is demonstrated on the experimental model of cholera. Underlined is the prospective use of probiotics as additional preparations of choice against cholera infection

Analysis of Genetic Determination of <I>Vibrio cholerae</I> Tweenase Activity

Studied are Vibrio cholerae of different serogroups on the presence of cef (CHO cell elongating factor) gene and activity against tweens and tributyrin using HDS-agar, prepared on the basis of bakery yeast pancreatic digest. Determined is the fact that all cef-positive strains hydrolyze tweens 20, 40, 60, 80, 85 and all but toxigenic V.cholerae O139, hydrolyze tributyrin. In contrast, non-toxigenic cef-negative strains of O139 serogroup, are active only against the latter. Apparently, the tweenase activity of Vibrio cholerae is provided, partly, by Cef, and the ability to hydrolyze tributyrin is the result of combined activity of Cef and other ferments. Shown is the efficiency of HDS-agar application to determine these characteristics

Analysis of the Results of Cholera Vibrios Monitoring in Environmental Objects in the Administrative Territories of the Russian Federation Using GIS “CHOLERA 1989–2014”

Objective of the work was to compare the results of monitoring of Vibrio cholerae strains isolated in the territories of federal districts, their constituent entities and from certain water bodies between 2006–2016. Based on the methodology, using updated geoinformation system “Cholera 1989–2014”, a comparative study of the dynamics of isolation and biological properties of 586 Vibrio cholerae O1, O139 strains and R-variants, collected from the surface water bodies in the administrative territories of Russia, was carried out. Eventually it is established that Vibrio cholerae strains of various serogroups are found in the territory of all federal districts, but not in all the entities included in them. It is shown that the greatest number of isolated strains was registered in the Southern Federal District. The overwhelming number of Vibrio cholerae strains, isolated in the country, were non-toxigenic. It was noted that against the background of epidemiological welfare, the detection of single epidemiologically significant strains continued (Rostov Region).ctxA–tcpA+ strains were found in the Southern, Far Eastern and North-Western Federal Districts. It is established that until 2013 in five constituent entities strains of Vibrio cholerae O1 and O139 in water bodies were not detected. Non-toxigenic strains of Vibrio cholerae O1 El Tor Ogawa serovar prevailed in the territories of the Southern and Ural, and Inaba serovar – in the remaining Federal Districts.The most frequently isolated were non-toxigenic Vibrio cholerae O1 strains with phagotype 15, while isolates with phagotypes 4, 5, 10, 14 and 17 were traced only in the Southern Federal District. The data obtained formed the basis of the approach that contributes to a comprehensive assessment of the epidemiological situation on cholera in the territory of Russia and highlighted the prospects for using GIS to improve the effectiveness of cholera vibrio monitoring in surface water bodies

СПОСОБ РЕАЛИЗАЦИИ ИНФОРМАЦИОННОЙ МОДЕЛИ ОБСТАНОВКИ В АВТОМАТИЗИРОВАННОЙ СИСТЕМЕ УПРАВЛЕНИЯ

The new way, allowing to define quantity of hierarchical levels in management, in relation to information model of an automated control system, and allowing to optimize load of the person making the decision is offered.Предложен способ нахождения количественной оценки числа иерархических уровней управления информационной моделью автоматизированной системы управления (АСУ) с целью оптимизации загруженности лица, принимающего решение

Study of the Surface Antigenic Determinants of <i>Vibrio cholerae</i> Strains with Atypical Agglutinability Using the Panel of Monoclonal Antibodies

The aim of the work was to study surface antigenic determinants of V. cholerae R-variant strains using enzyme immunoassay and a panel of monoclonal antibodies (MAbs).Materials and methods. 60 strains of V. cholerae R-variant isolated from ambient environment objects in the territories of the former USSR and the constituent entities of the Russian Federation over a 30-year period (1988–2019) were investigated in the slide agglutination reaction with cholera diagnostic sera, enzyme immunoassay (ELISA) using the panel of MAbs specific to membrane proteins and a set of reagents “Monoclonal diagnostic immunoglobulins labeled with horseradish peroxidase, dry, for serological identification of V. cholerae O1 and O139 (in vitro) through ELISA and dot-ELISA”.Results and discussion. The analysis of the surface structures of V. cholerae R-variant strains with atypical agglutinability has been carried out applying enzyme immunoassay. It showed that individual strains with different amounts of O-antigen are registered among the studied strains identified at isolation as V. cholerae R-variant (the optical density range is from 0.261±0.002 to 1.312±0.003). Epitopes of specific O-antigen were found in some “conservative” strains (30 %) that are agglutinated only with RO serum, and in several strains (20 %) that do not have the wbeT gene that determines its synthesis, and lost agglutinability with all diagnostic cholera sera, including RO. The protein epitopes recognized by complementary MAbs are represented with varying frequency in the composition of surface antigens of R-vibrios; a decrease in their representation or absence on the cell surface correlates with the modification or loss of R-LPS and is accompanied by a negative agglutination reaction

Epidemiological Situation on Cholera throughout the World in 2013, Forecasting for 2014

V. cholerae O1 El Tor cultures, serovars Ogawa and Inaba, from surface waters of the reservoirs, which are different in epidemic manifestations of the disease

Cholera Vibrios non-O1/non-O139 Isolated in the Process of Epidemiological Monitoring over Rostov-on-Don Water Basins and Drain Sewage System within the Period of 2009–2011

Studied have been biological properties of cholera vibrios non-O1/non-O139 circulating in the Rostov-on-Don surface waters and drain sewage system within the period of 2009–2011. Overwhelming majority of the isolates have been classified as typical ones in terms of their phenotype. However 90 strains (21 %) out of total 280 have been identified as atypical ones against agglu­tina­bility in the slide-agglutination and full-scale agglutination reaction to diagnostic cholera sera. Put forward are recommendations on performance of the differentiation between V. cholerae non-O1/non-O139 and V. cholerae O1/O139. Specified are predominant sero­groups of the strains which turned to be unchanged within the stated period (O16, O53, O76, and O67). Revealed is the strain genotype variability and low probability of virulence manifestations. Demonstrated is the futility of the blind gene- and serological typing of aquatic strains

Investigation of the Lipopolysaccharide Cluster Structure in the Genomes of <i>Vibrio cholerae</i> Rough Variants

Determination of Vibrio cholerae affiliation to one or another serogroup may meet some difficulties in cases of atypical agglutination with diagnostic cholera sera. The study of genetic determinants that allows for identifying a serogroup is a relevant task in monitoring of surface water body contamination with cholera vibrios.The aim of the work was to compare the structural organization (quantitative and qualitative gene composition) of LPS clusters in V. cholerae rough variants.Materials and methods. We used Illumina MiSeq for the whole genome sequencing; SPAdes software (version 3.11.1) for de novo assembly; and blastn (v. 2.5.0) for gene searching. GeneMarkS software was deployed for annotation of the genes incorporated in the clusters; nucmer – for searching homologous sites. Visualization of O-LPS clusters was carried out by means of SnapGene Viewer.Results and discussion. Strains of V. cholerae rough variants had diverse gene clusters responsible for O-antigen biosynthesis. We have identified three types of O-LPS clusters with different size and number of genes. Unique DNA sites, common to the whole group of V. cholerae rough variants, have not been detected. Two genes present in all rough strains have been defined, but they are not unique for this group of strains and can be found in representatives of other serogroups. For two types of clusters, a region containing the IS‑element, common with V. cholerae O1, has been revealed