Investigating volatile compounds in the Bacteroides secretome

Microorganisms and their hosts communicate with each other by secreting numerous components. This cross-kingdom cell-to-cell signaling involves proteins and small molecules, such as metabolites. These compounds can be secreted across the membrane via numerous transporters and may also be packaged in outer membrane vesicles (OMVs). Among the secreted components, volatile compounds (VOCs) are of particular interest, including butyrate and propionate, which have proven effects on intestinal, immune, and stem cells. Besides short fatty acids, other groups of volatile compounds can be either freely secreted or contained in OMVs. As vesicles might extend their activity far beyond the gastrointestinal tract, study of their cargo, including VOCs, is even more pertinent. This paper is devoted to the VOCs secretome of the Bacteroides genus. Although these bacteria are highly presented in the intestinal microbiota and are known to influence human physiology, their volatile secretome has been studied relatively poorly. The 16 most well-represented Bacteroides species were cultivated; their OMVs were isolated and characterized by NTA and TEM to determine particle morphology and their concentration. In order to analyze the VOCs secretome, we propose a headspace extraction with GC–MS analysis as a new tool for sample preparation and analysis of volatile compounds in culture media and isolated bacterial OMVs. A wide range of released VOCs, both previously characterized and newly described, have been revealed in media after cultivation. We identified more than 60 components of the volatile metabolome in bacterial media, including fatty acids, amino acids, and phenol derivatives, aldehydes and other components. We found active butyrate and indol producers among the analyzed Bacteroides species. For a number of Bacteroides species, OMVs have been isolated and characterized here for the first time as well as volatile compounds analysis in OMVs. We observed a completely different distribution of VOC in vesicles compared to the bacterial media for all analyzed Bacteroides species, including almost complete absence of fatty acids in vesicles. This article provides a comprehensive analysis of the VOCs secreted by Bacteroides species and explores new perspectives in the study of bacterial secretomes in relation the intercellular communication

New Antiarrhythmic Agent to Stabilize Functional Activity of Rat Heart Sinus Node Cardiomyocytes

Introduction: The aim of this study was to explore the antiarrhythmic activity of the new antiarrhythmic drug, succinic acid ester of 5-hydroxyadamantane-2-one (ADK-1110) and its effect on the functional activity of rat heart sinus node. Materials and methods: Experiments were performed on 80 non-linear white awake male rats weighing 200 g, using calcium chloride and aconitine arrhythmia models. The ECG was recorded from all the animals in the II standard lead before the start of the experiment. The effect of ADK-1110 on the electrical activity characteristics of rat heart sinus node pacemakers in vitro was studied on 26 outbred Wistar rats of both sexes with a body weight of 160 to 200 g, using the microelectrode technique. Results and discussion: The compound significantly exceeds the known reference drugs in terms of the antiarrhythmic index. The agent also surpasses our previously proposed adamantane derivative ADK-1100 on calcium chloride model and is not inferior to the aconitine one. The electrophysiological analysis of the sinus node pacemaker cardiomyocytes characteristics in vitro under the influence of ADK-1110 revealed that the compound expands the area occupied by true pacemakers. Discussion: The obtained data indicate the presence of properties of antiarrhythmics of classes I, III, and IV in ADK-1110. The indicated functional remodeling stabilizes the functional activity of the central part of the sinus node. Conclusion: ADK-1110 stabilizes the functional activity of the central part of the sinus node. ADK-1110 also has a cerebrovascular anti-ischemic property

Association between Taxonomic Composition of Gut Microbiota and Host Single Nucleotide Polymorphisms in Crohn’s Disease Patients from Russia

Crohn’s disease (CD) is a chronic relapsing inflammatory bowel disease of unknown etiology. Genetic predisposition and dysbiotic gut microbiota are important factors in the pathogenesis of CD. In this study, we analyzed the taxonomic composition of the gut microbiota and genotypes of 24 single nucleotide polymorphisms (SNP) associated with the risk of CD. The studied cohorts included 96 CD patients and 24 healthy volunteers from Russia. Statistically significant differences were found in the allele frequencies for 8 SNPs and taxonomic composition of the gut microbiota in CD patients compared with controls. In addition, two types of gut microbiota communities were identified in CD patients. The main distinguishing driver of bacterial families for the first community type are Bacteroidaceae and unclassified members of the Clostridiales order, and the second type is characterized by increased abundance of Streptococcaceae and Enterobacteriaceae. Differences in the allele frequencies of the rs9858542 (BSN), rs3816769 (STAT3), and rs1793004 (NELL1) were also found between groups of CD patients with different types of microbiota communities. These findings confirm the complex multifactorial nature of CD