GC-MS with Headspace Extraction for Non-Invasive Diagnostics of IBD Dynamics in a Model of DSS-Induced Colitis in Rats.

Inflammatory bowel diseases are extremely common throughout the world. However, in most cases, it is asymptomatic at the initial stage. Therefore, it is important to develop non-invasive diagnostic methods that allow identification of the IBD risks in a timely manner. It is well known that gastrointestinal microbiota secrete volatile compounds (VOCs) and their composition may change in IBD. We propose a non-invasive method to identify the dynamics of IBD development in the acute and remission stage at the level of VOCs in model of dextran sulfate sodium (DSS) with chemically induced colitis measured by headspace GC/MS (HS GC/MS). Methods: VOCs profile was identified using a headspace GC/MS (HS GC/MS). GC/MS data were processed using MetaboAnalyst 5.0 and GraphPad Prism 8.0.1 software. The disease activity index (DAI) and histological method were used to assess intestinal inflammation. The peak of intestinal inflammation activity was reached on day 7, according to the disease activity index. Histological examination data showed changes in the intestine due to different stages of inflammation. As the acute inflammation stage was reached, the metabolomic profile also underwent changes, especially at the short-fatty acids level. A higher relative amounts of acetic acid (p value < 0.025) and lower relative amounts of propanoic acid (p value < 0.0005), butanoic acid (p value < 0.005) and phenol 4-methyl- (p value = 0.053) were observed in DSS7 group on day 7 compared to the control group. In remission stage, disease activity indexes decreased, and the histological picture also improved. But metabolome changes continued despite the withdrawal of the DSS examination. A lower relative amounts of propanoic acid (p value < 0.025), butanoic acid (p value < 0.0005), pentanoic acid (p value < 0.0005), and a significant de-crease of hexanoic acid (p value < 0.0005) relative amounts were observed in the DSS14 group compared to the control group on day 14. A model of DSS-induced colitis in rats was successfully implemented for metabolomic assessment of different stages of inflammation. We demonstrated that the ratios of volatile compounds change in response to DSS before the appearance of standard signs of inflammation, determined by DAI and histological examination. Changes in the volatile metabolome persisted even after visual intestine repair and it confirms the high sensitivity of the microbiota to the damaging effects of DSS. The use of HS GC/MS may be an important addition to existing methods for assessing inflammation at early stages.

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.

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.

Coexistence of Two Rare Genetic Variants in Canonical and Non-canonical Exons of SCN5A: A Potential Source of Misinterpretation.

Primary cardiac channelopathies are a group of diseases wherein the role of DNA testing in aiding diagnosis and treatment-based decision-making is gaining increasing attention. However, in some cases, evaluating the pathogenicity of new variants is still challenging. We report an accurate multistage assessment of a rare genetic variant in the SCN5A gene using next-generation sequencing (NGS) techniques and Sanger sequencing. Female sportsman (14 years old) underwent genetic counseling and DNA testing due to QT interval prolongation registered during ECG Holter monitoring. Genetic testing of the proband was performed in two independent laboratories. Primary DNA testing was performed by WES using the Ion ProtonTM System. Target panel sequencing of 11 genes was performed using PGM Ion Torrent. Search for variants in non-canonical and canonical exons 6 was performed by Sanger sequencing. The cascade familial screening and control re-sequencing were provided for proband with identified genetic variant p.S216L (g.38655290G>A, NM_198056.2:c.647C>T, and rs41276525) in the canonical exon 6 of the SCN5A gene after receiving data from another laboratory. Control Sanger and NGS sequencing revealed the absence p.S216L in the canonical exon 6 and confirmed the presence of p.S216L (g.38655522G>A, c.647C>T, and rs201002736) in the non-canonical exon 6 of the SCN5A gene. The identified variant was re-interpreted. The non-canonical transcripts of the exon 6 of the SCN5A gene is poorly represented in cardiac tissue (gnomAD). The detected variant was found in proband's healthy mother. The correct interpretation of genetic data requires close cooperation between clinicians and researchers. It can help to avoid financial costs and stress for proband's and families.

Susceptibility of Virulent Yersinia pestis Bacteria to Predator Bacteria in the Lungs of Mice.

Multi-drug resistant bacterial infections are a serious threat to global public health. Changes in treatment modalities and prudent use of antibiotics can assist in reducing the threat, but new approaches are also required for untreatable cases. The use of predatory bacteria, such as Bdellovibrio bacteriovorus, is among the novel approaches being considered as possible therapeutics for antibiotic resistant and/or unidentified bacterial infections. Previous studies have examined the feasibility of using predatory bacteria to reduce colony-forming units (CFUs) in the lungs of rats exposed to lethal doses of Klebsiella pneumoniae; here we apply the approach to the Tier 1 select agent Yersinia pestis, and show that three doses of B. bacteriovorus introduced every six hours reduces the number of CFUs of Y. pestis in the lungs of inoculated mice by 86% after 24 h of infection. These experiments further demonstrate that predatory bacteria may serve to combat Gram negative bacterial infections, including those considered potential bioweapon agents, in the future.

The gendered effects of foreign investment and prolonged state ownership on mortality in Hungary: an indirect demographic, retrospective cohort study.

BACKGROUND: Research on the health outcomes of globalisation and economic transition has yielded conflicting results, partly due to methodological and data limitations. Specifically, the outcomes of changes in foreign investment and state ownership need to be examined using multilevel data, linking macro-effects and micro-effects. We exploited the natural experiment offered by the Hungarian economic transition by means of a multilevel study designed to address these gaps in the scientific literature. METHODS: For this indirect demographic, retrospective cohort study, we collected multilevel data related to Hungary between 1995 and 2004 from the PrivMort database and other sources at the town, company, and individual level to assess the relation between the dominant company ownership of a town and mortality. We grouped towns into three ownership categories: dominant state, domestic private, and foreign ownership. We did population surveys in these towns to collect data on vital status and other characteristics of survey respondents' relatives. We assessed the relation between dominant ownership and mortality at the individual level. We used discrete-time survival modelling, adjusting for town-level and individual-level confounders, with clustered SEs. FINDINGS: Of 83 eligible towns identified, we randomly selected 52 for inclusion in the analysis and analysed ownership data from 262 companies within these towns. Additionally, between June 16, 2014, and Dec 22, 2014, we collected data on 78 622 individuals from the 52 towns, of whom 27 694 were considered eligible. After multivariable adjustment, we found that women living in towns with prolonged state ownership had significantly lower odds of dying than women living in towns dominated by domestic private ownership (odds ratio [OR] 0·74, 95% CI 0·61-0·90) or by foreign investment (OR 0·80, 0·69-0·92). INTERPRETATION: Prolonged state ownership was associated with protection of life chances during the post-socialist transformation for women. The indirect economic benefits of foreign investment do not translate automatically into better health without appropriate industrial and social policies. FUNDING: The European Research Council.

Asymmetric Structure of the Dimerization Domain of PhoR, a Sensor Kinase Important for the Virulence of Mycobacterium tuberculosis.

The PhoP-PhoR two-component system is essential for the virulence of Mycobacterium tuberculosis (Mtb) and therefore represents a potential target for developing novel antituberculosis therapies. However, little is known about the mechanism by which this two-component system regulates the virulence. In this study, we demonstrated that a phoR mutant Mtb strain has phenotypes similar to those of a phoP mutant, suggesting that PhoP and PhoR work in the same pathway to regulate Mtb virulence. We determined the structure of the dimerization and histidine phosphotransfer (DHp) domain of PhoR to a 1.9 Å resolution. The structure revealed that the DHp domain is a dimer. Each subunit consists of two antiparallel α helices connected by a loop of five residues. The two subunits of the dimer fold into a four-helical bundle with a continuous hydrophobic core. The topology of the four-helical bundle is identical to the histidine kinases that are known to have a cis-autophosphorylation mechanism, suggesting that PhoR is likely to autophosphorylate in cis. The dimer is asymmetric, with one subunit having a greater bending angle than the other at the highly conserved proline residue five-residues downstream of the phosphorylation site histidine. This structural asymmetry of the dimer suggests the flexibility of the PhoR DHp domain, which is likely to be important for the signal transduction mechanism in controlling the autophosphorylation and phosphotransfer reactions and communicating with the upstream structure.

The effect of rapid privatisation on mortality in mono-industrial towns in post-Soviet Russia: a retrospective cohort study.

BACKGROUND: Population-level data suggest that economic disruptions in the early 1990s increased working-age male mortality in post-Soviet countries. This study uses individual-level data, using an indirect estimation method, to test the hypothesis that fast privatisation increased mortality in Russia. METHODS: In this retrospective cohort study, we surveyed surviving relatives of individuals who lived through the post-communist transition to retrieve demographic and socioeconomic characteristics of their parents, siblings, and male partners. The survey was done within the framework of the European Research Council (ERC) project PrivMort (The Impact of Privatization on the Mortality Crisis in Eastern Europe). We surveyed relatives in 20 mono-industrial towns in the European part of Russia (ie, the landmass to the west of the Urals). We compared ten fast-privatised and ten slow-privatised towns selected using propensity score matching. In the selected towns, population surveys were done in which respondents provided information about vital status, sociodemographic and socioeconomic characteristics and health-related behaviours of their parents, two eldest siblings (if eligible), and first husbands or long-term partners. We calculated indirect age-standardised mortality rates in fast and slow privatised towns and then, in multivariate analyses, calculated Poisson proportional incidence rate ratios to estimate the effect of rapid privatisation on all-cause mortality risk. FINDINGS: Between November, 2014, and March, 2015, 21 494 households were identified in 20 towns. Overall, 13 932 valid interviews were done (with information collected for 38 339 relatives [21 634 men and 16 705 women]). Fast privatisation was strongly associated with higher working-age male mortality rates both between 1992 and 1998 (age-standardised mortality ratio in men aged 20-69 years in fast vs slow privatised towns: 1·13, SMR 0·83, 95% CI 0·77-0·88 vs 0·73, 0·69-0·77, respectively) and from 1999 to 2006 (1·15, 0·91, 0·86-0·97 vs 0·79, 0·75-0·84). After adjusting for age, marital status, material deprivation history, smoking, drinking and socioeconomic status, working-age men in fast-privatised towns experienced 13% higher mortality than in slow-privatised towns (95% CI 1-26). INTERPRETATION: The rapid pace of privatisation was a significant factor in the marked increase in working-age male mortality in post-Soviet Russia. By providing compelling evidence in support of the health benefits of a slower pace of privatisation, this study can assist policy makers in making informed decisions about the speed and scope of government interventions. FUNDING: The European Research Council.

Mortality in Transition: Study Protocol of the PrivMort Project, a multilevel convenience cohort study.

BACKGROUND: Previous research using routine data identified rapid mass privatisation as an important driver of mortality crisis following the collapse of Communism in Central and Eastern Europe. However, existing studies on the mortality crisis relying on individual level or routine data cannot assess both distal (societal) and proximal (individual) causes of mortality simultaneously. The aim of the PrivMort Project is to overcome these limitations and to investigate the role of societal factors (particularly rapid mass privatisation) and individual-level factors (e.g. alcohol consumption) in the mortality changes in post-communist countries. METHODS: The PrivMort conducts large-sample surveys in Russia, Belarus and Hungary. The approach is unique in comparing towns that have undergone rapid privatisation of their key industrial enterprises with those that experienced more gradual forms of privatisation, employing a multi-level retrospective cohort design that combines data on the industrial characteristics of the towns, socio-economic descriptions of the communities, settlement-level data, individual socio-economic characteristics, and individuals' health behaviour. It then incorporates data on mortality of different types of relatives of survey respondents, employing a retrospective demographic approach, which enables linkage of historical patterns of mortality to exposures, based on experiences of family members. By May 2016, 63,073 respondents provided information on themselves and 205,607 relatives, of whom 102,971 had died. The settlement-level dataset contains information on 539 settlements and 12,082 enterprises in these settlements in Russia, 96 settlements and 271 enterprises in Belarus, and 52 settlement and 148 enterprises in Hungary. DISCUSSION: In addition to reinforcing existing evidence linking smoking, hazardous drinking and unemployment to mortality, the PrivMort dataset will investigate the variation in transition experiences for individual respondents and their families across settlements characterized by differing contextual factors, including industrial characteristics, simultaneously providing information about how excess mortality is distributed across settlements with various privatization strategies.

A thiolase of Mycobacterium tuberculosis is required for virulence and production of androstenedione and androstadienedione from cholesterol.

Mycobacterium tuberculosis, the causative agent of tuberculosis, is an intracellular pathogen that shifts to a lipid-based metabolism in the host. Moreover, metabolism of the host lipid cholesterol plays an important role in M. tuberculosis infection. We used transcriptional profiling to identify genes transcriptionally regulated by cholesterol and KstR (Rv3574), a TetR-like repressor. The fadA5 (Rv3546) gene, annotated as a lipid-metabolizing thiolase, the expression of which is upregulated by cholesterol and repressed by KstR, was deleted in M. tuberculosis H37Rv. We demonstrated that fadA5 is required for utilization of cholesterol as a sole carbon source in vitro and for full virulence of M. tuberculosis in the chronic stage of mouse lung infection. Cholesterol is not toxic to the fadA5 mutant strain, and, therefore, toxicity does not account for its attenuation. We show that the wild-type strain, H37Rv, metabolizes cholesterol to androst-4-ene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD) and exports these metabolites into the medium, whereas the fadA5 mutant strain is defective for this activity. We demonstrate that FadA5 catalyzes the thiolysis of acetoacetyl-coenzyme A (CoA). This catalytic activity is consistent with a beta-ketoacyl-CoA thiolase function in cholesterol beta-oxidation that is required for the production of androsterones. We conclude that the attenuated phenotype of the fadA5 mutant is a consequence of disrupted cholesterol metabolism that is essential only in the persistent stage of M. tuberculosis infection and may be caused by the inability to produce AD/ADD from cholesterol.

The Mycobacterium tuberculosis PhoPR two-component system regulates genes essential for virulence and complex lipid biosynthesis.

Two-component signal transduction systems (2-CS) play an important role in bacterial pathogenesis. In the work presented here, we have studied the effects of a mutation in the Mycobacterium tuberculosis (Mtb) PhoPR 2-CS on the pathogenicity, physiology and global gene expression of this bacterial pathogen. Disruption of PhoPR causes a marked attenuation of growth in macrophages and mice and prevents growth in low-Mg2+ media. The inability to grow in THP-1 macrophages can be partially overcome by the addition of excess Mg2+ during infection. Global transcription assays demonstrate PhoP is a positive transcriptional regulator of several genes, but do not support the hypothesis that the Mtb PhoPR system is sensing Mg2+ starvation, as is the case with the Salmonella typhimurium PhoPQ 2-CS. The genes that were positively regulated include those found in the pks2 and the msl3 gene clusters that encode enzymes for the biosynthesis of sulphatides and diacyltrehalose and polyacyltrehalose respectively. Complementary biochemical studies, in agreement with recent results from another group, indicate that these complex lipids are also absent from the phoP mutant, and the lack of these components in its cell envelope may indirectly cause the mutant's high-Mg2+ growth requirement. The experiments reported here provide functional evidence for the PhoPR 2-CS involvement in Mtb pathogenesis, and they suggest that a major reason for the attenuation observed in the phoP mutant is the absence of certain complex lipids that are known to be important for virulence.