Antibiotic resistance in Vibrio cholerae El Tor strains isolated during cholera complications in Siberia and the Far East of Russia.

Currently, the spread of antimicrobial resistance (AMR) is a global trend and poses a severe threat to public health. The causative agent of cholera, a severe infectious disease with pandemic expansion, becomes more and more resistant to a wider range of drugs with every coming year. The Vibrio cholerae genome is highly flexible and adaptive; the acquisition of the SXT mobile element with a cluster of antibiotic resistance genes on it has marked a new stage in the adaptive evolution of the pathogen. The territory of Siberia and the Russian Far East is free of cholera; however, in the 1970s and 1990s a number of infection importation cases and acute outbreaks associated with the cholera importation were reported. The aim of this study was to describe the phenotypic characteristics and genetic determinants of AMR in V. cholerae strains isolated during epidemic complications in Siberia and the Far East of Russia, as well as to clarify the origin of the strains. The present research comprises analysis of nine V. cholerae El Tor strains isolated from patients and water sources during epidemic complications in Siberia and the Russian Far East in the 1990s. Here, we compared the phenotypic manifestations of antibiotic resistance among strains, harbored the resistance patterns in genomes; we also determined the structure, the type of SXT elements, and the mobilome profile based on the accepted classification. We identified that strains that caused outbreaks in Vladivostok and Yuzhno-Sakhalinsk in 1999 had ICEVchCHN4210 type SXT element with deletion of some loci. The research shows that the integration of the genome, SNP and the mobilome, associated with antibiotic resistance, analyses is necessary to understand the cholera epidemiology, it also helps to establish the origin of strains. The study of resistance determinants features allowed to make a conclusion about the heterogeneity of V. cholerae strains that were isolated during outbreaks in Vladivostok and Yuzhno-Sakhalinsk in 1999.

Composition and Structure of Gut Microbiome in Adolescents with Obesity and Different Breastfeeding Duration.

Gut microbiome of adolescents with obesity and different duration of breastfeeding was analyzed by metagenomic analysis of V3-V4 variable domains of the 16S rRNA gene. In subgroup with breastfeeding duration <3 months, intrapopulation structure of gut microbiome by alpha diversity indices was similar in adolescents with obesity and normal body weight. The decrease in phylotype abundance in the structure of communities was associated only with obesity, while dysbiotic state persisted in both lean and overweight adolescents, which confirmed the effect of breastfeeding duration on stability of gut microbiome.

Molecular modeling of human lanosterol 14α-demethylase complexes with substrates and their derivatives.

Lanosterol 14α-demethylase (CYP51A1) is a key enzyme in sterol biosynthesis. In humans, this enzyme is involved in the cholesterol biosynthesis pathway. The majority of antifungal drugs are aimed at the inhibition of CYP51 in fungi. To elucidate the molecular mechanisms of highly specific protein-ligand recognition, we have developed a full-atomic model of human CYP51A1 and performed docking of natural substrates and their derivatives to the active site of the enzyme. The parameters of the binding enthalpy of substrates, intermediates, and final products of the reaction of 14α-demethylation were estimated using the MMPB(GB)SA algorithm. Dynamic properties and conformational changes of the protein globule upon binding of the ligand near the active site have been investigated by the molecular dynamics method. Our studies reveal that hydroxylated intermediate reaction products have a greater affinity than the initial substrates, which facilitates the multistage reaction without accumulation of intermediate products. The contribution to the free energy of steroid ligand binding of 30 amino acids forming the substrate-binding region of CYP51A1, as well as the influence of their substitutions to alanine on the stability of the protein molecule, has been clarified using alanine scanning modeling. We demonstrate that the most serious weakening of the binding is observed in the case of substitutions Y137A, F145A, V149A, I383A, and R388A. The results of molecular modeling are in agreement with the data obtained by analysis of primary sequences of representatives of the CYP51 family.

[GeneBee-NET: An Internet based server for biopolymer structure analysis]. / GeneBee-NET: Baziruiushchiisia v seti Internet server po analizu struktur biopolimerov.

A network server providing biopolymer structure databank retrieval as well as some other biocomputing procedures for Internet users is described. Its basic procedures consist in looking for sequence and 3D homologies (similarities). Found homologies are used for constructing multiple alignment, for predicting RNA and protein secondary structures as well as for constructing phylogenetic trees. Alongside traditional methods of sequence homology retrieval, a "matrix-free" (correlation) method is proposed. A similar procedure is used to locate protein 3D similarities. For novel procedures algorithm ideas and their possible applications are discussed. The service ideology is based on the interaction of server and client programs. The client program (GeneBee for IBM PC) can be used to form queries to the server as well as to manipulate a treatment result. In the absence of the client program the interaction with the server can be in the text mode. The E-mail and WWW addresses for the server are as follows: SERVE/INDY.GENEBEE.MSU.SU and WWW.GENEBEE.MSU.SU.

A novel method of multiple alignment of biopolymer sequences.

A novel algorithm for multiple alignment of biological sequences is suggested. At the first step the DotHelix procedure is employed for construction of motifs, i.e. continuous fragments of local similarity of various "thickness" and strength, and then these motifs are concatenated into chains consistent with the order of letters in the sequences. The algorithm is implemented in the MA-Tools program of the GeneBee package. An example illustrating the effectivity of the algorithm is presented.