-
Electrophoresis Oct 2019Tuberculosis is highly persistent and displays phenotypic resistance to high concentrations of antimicrobials. Recent reports exhibited that Mycobacterium tuberculosis... (Comparative Study)
Comparative Study
Tuberculosis is highly persistent and displays phenotypic resistance to high concentrations of antimicrobials. Recent reports exhibited that Mycobacterium tuberculosis biofilm was implicated to its pathogenicity and drug resistance. In this study, there were 47 kinds of differential proteins in the biofilm of M. tuberculosis H37Rv cells compared with the planktonic bacteria, and 37 proteins were nonredundant and identified by proteomics approach, such as 2DE and LC-MS/MS. Moreover, six kinds of proteins were identified as HspX, which were conservative and highly expressed in biofilm. Note that 47 differential proteins were divided into seven categories, such as cell wall and cell processes, conserved hypotheticals, intermediary metabolism and respiration, and so on by TUBERCULIST. The Gene Ontology classification results showed that the largest protein group involved in metabolism, binding proteins, and catalytic function accounts for 30% and 57% of all identified proteins, respectively. Moreover, the protein interaction network analyzed by STRING showed that the minority proteins such as RpoA, SucC, Cbs, Tuf, DnaK, and GroeL in the interaction network have high network connectivity. These results implied that the proteins involved in metabolic process and catalytic function and the minority proteins mentioned above may play an important role in M. tuberculosis biofilm formation. To our knowledge, this is the first report about differential proteins between biofilm and planktonic M. tuberculosis, which provided the potential antigens for vaccines and target proteins for anti-mycobacterial drugs.
Topics: Bacterial Proteins; Biofilms; Mycobacterium tuberculosis; Protein Interaction Maps; Proteome; Proteomics
PubMed: 31141184
DOI: 10.1002/elps.201900030 -
ACS Infectious Diseases Aug 2019MTBVAC is a live attenuated vaccine constructed by genetic deletions in the and virulence genes. The MTBVAC vaccine is currently in phase 2 clinical trials with... (Comparative Study)
Comparative Study
MTBVAC is a live attenuated vaccine constructed by genetic deletions in the and virulence genes. The MTBVAC vaccine is currently in phase 2 clinical trials with newborns and adults in South Africa, one of the countries with the highest incidence. Although MTBVAC has been extensively characterized by genomics, transcriptomics, lipidomics, and proteomics, its metabolomic profile is yet unknown. Accordingly, in this study we aim to identify differential metabolites between and MTBVAC. To this end, an untargeted metabolomics approach based on liquid chromatography coupled to high-resolution mass spectrometry was implemented in order to explore the main metabolic differences between and MTBVAC. As an outcome, we identified a set of 34 metabolites involved in diverse bacterial biosynthetic pathways. A consistent increase in the phosphatidylinositol species was observed in the vaccine candidate relative to its parental strain. This phenotype resulted in an increased production of phosphatidylinositol mannosides, a novel PhoP-regulated phenotype in the most widespread lineages of . This study represents a step ahead in our understanding of the MTBVAC vaccine, and some of the differential metabolites identified in this work might be used as potential vaccination biomarkers.
Topics: Bacterial Proteins; Biosynthetic Pathways; Chromatography, Liquid; Mass Spectrometry; Metabolomics; Mycobacterium tuberculosis; Phosphatidylinositols; Tuberculosis Vaccines
PubMed: 31099236
DOI: 10.1021/acsinfecdis.9b00008 -
Transcriptional signatures of Mycobacterium tuberculosis in mouse model of intraocular tuberculosis.Pathogens and Disease Jul 2019Studies on human intraocular tuberculosis (IOTB) are extremely challenging. For understanding the pathogenesis of IOTB, it is important to investigate the mycobacterial...
BACKGROUND
Studies on human intraocular tuberculosis (IOTB) are extremely challenging. For understanding the pathogenesis of IOTB, it is important to investigate the mycobacterial transcriptional changes in ocular environment.
METHODS
Mice were challenged intravenously with Mycobacterium tuberculosis H37Rv and at 45 days post-infection, experimental IOTB was confirmed based on bacteriological and molecular assays. M. tuberculosis transcriptome was analyzed in the infected eyes using microarray technology. The identified M. tuberculosis signature genes were further validated and investigated in human IOTB samples using real-time polymerase chain reaction.
RESULTS
Following intravenous challenge with M. tuberculosis, 45% (5/12) mice showed bacilli in the eyes with positivity for M. tuberculosis ribonucleic acid in 100% (12/12), thus confirming the paucibacillary nature of IOTB similar to human IOTB. M. tuberculosis transcriptome in these infected eyes showed significant upregulation of 12 M. tuberculosis genes and five of these transcripts (Rv0962c, Rv0984, Rv2612c, Rv0974c and Rv0971c) were also identified in human clinically confirmed cases of IOTB.
CONCLUSIONS
Differentially expressed mycobacterial genes identified in an intravenously challenged paucibacillary mouse IOTB model and presence of these transcripts in human IOTB samples highlight the possible role of these genes for survival of M. tuberculosis in the ocular environment, thus contributing to pathogenesis of IOTB.
Topics: Animals; Disease Models, Animal; Humans; Mice; Microarray Analysis; Mycobacterium tuberculosis; Real-Time Polymerase Chain Reaction; Transcriptome; Tuberculosis, Ocular; Virulence Factors
PubMed: 31504463
DOI: 10.1093/femspd/ftz045 -
Trends in Microbiology Jan 2016The proteasome system of Mycobacterium tuberculosis is required for causing disease. Proteasomes are multisubunit chambered proteases and, until recently, were only... (Review)
Review
The proteasome system of Mycobacterium tuberculosis is required for causing disease. Proteasomes are multisubunit chambered proteases and, until recently, were only known to participate in adenosine triphosphate (ATP)-dependent proteolysis in bacteria. In this review, we discuss the latest advances in understanding how both ATP-dependent and ATP-independent proteasome-regulated pathways contribute to M. tuberculosis virulence.
Topics: Animals; Bacterial Proteins; Humans; Mycobacterium tuberculosis; Tuberculosis; Virulence
PubMed: 26526503
DOI: 10.1016/j.tim.2015.10.001 -
Future Microbiology May 2018Mycobacterium tuberculosis is an intracellular bacterium that persists and replicates inside macrophages. The bacterium possesses an unusual lipid-rich cell envelope... (Review)
Review
Mycobacterium tuberculosis is an intracellular bacterium that persists and replicates inside macrophages. The bacterium possesses an unusual lipid-rich cell envelope that provides a hydrophobic impermeable barrier against many environmental stressors and allows it to survive extremely hostile intracellular surroundings. Since the lipid-rich envelope is crucial for M. tuberculosis virulence, the components of the cell wall lipid biogenesis pathways constitute an attractive target for the development of vaccines and antimycobacterial chemotherapeutics. In this review, we provide a detailed description of the mycobacterial cell envelope lipid components and their contributions to the physiology and pathogenicity of mycobacteria. We also discussed the current status of the antimycobacterial drugs that target biosynthesis, export and regulation of cell envelope lipids.
Topics: Cell Wall; Lipid Metabolism; Mycobacterium tuberculosis; Tuberculosis; Virulence Factors
PubMed: 29771143
DOI: 10.2217/fmb-2017-0135 -
Trends in Microbiology Nov 2019Mycobacterium tuberculosis (Mtb) senses and adapts to acidic host environments during the course of pathogenesis. Mutants defective in acidic pH-dependent adaptations... (Review)
Review
Mycobacterium tuberculosis (Mtb) senses and adapts to acidic host environments during the course of pathogenesis. Mutants defective in acidic pH-dependent adaptations are often attenuated during macrophage or animal infections, supporting that these pathways are essential for pathogenesis and represent important new targets for drug discovery. This review examines a confluence of findings supporting that Mtb has restricted metabolism at acidic pH that results in the slowing of bacterial growth and changes in redox homeostasis. It is proposed that induction of the PhoPR regulon and anaplerotic metabolism, in concert with the restricted use of specific carbon sources, functions to counter reductive stress associated with acidic pH.
Topics: Adaptation, Physiological; Carbon; Hydrogen-Ion Concentration; Mycobacterium tuberculosis; Oxidation-Reduction; Tuberculosis
PubMed: 31324436
DOI: 10.1016/j.tim.2019.06.005 -
Indian Journal of Medical Microbiology 2017There have been rapid technological advances in the detection of Mycobacterium tuberculosis and its drug susceptibility in clinical samples. These include advances in... (Review)
Review
There have been rapid technological advances in the detection of Mycobacterium tuberculosis and its drug susceptibility in clinical samples. These include advances in microscopic examination, in vitro culture and application of molecular techniques. The World Health Organization (WHO) has played a large role in evaluating these technologies for their efficacy and feasibility, especially in the developing countries. Amongst these, the Revised National Tuberculosis Control Programme (RNTCP), through its national network of designated microscopy centres and intermediate reference laboratories, has adopted certain technologies that are currently implemented in India. Advances in microscopy technology include fluorescent microscopy using light-emitting diode source, sodium hypochlorite microscopy and vital fluorescent staining of sputum smears. Automation of in vitro culture has markedly reduced the turnaround time (TAT), even in smear-negative samples, and permits simultaneous detection of resistant mutants. Molecular detection of drug resistance has further reduced the TAT, and the cartridge-based nucleic acid amplification test with its performance convenience and rapid results, appears poised to become the future of tuberculosis (TB) diagnosis in all settings, provided the cost of testing is reduced especially for use in private diagnostic settings. This article reviews technologies currently available for the diagnosis of TB, keeping in mind the WHO recommendations and the RNTCP practices. This is a thematic synthesis of data available on diagnosis in literature, preserving the conclusions of the primary studies.
Topics: Clinical Laboratory Techniques; Humans; India; Mycobacterium tuberculosis; Tuberculosis
PubMed: 29063875
DOI: 10.4103/ijmm.IJMM_16_204 -
MBio Aug 2021Mycofactocin is a new class of peptide-derived redox cofactors present in a selected group of bacteria including Mycobacterium tuberculosis. Mycofactocin biosynthesis...
Mycofactocin is a new class of peptide-derived redox cofactors present in a selected group of bacteria including Mycobacterium tuberculosis. Mycofactocin biosynthesis requires at least six genes, including , encoding putative lactate dehydrogenase, which catalyzes the penultimate biosynthetic step. Cellular functions remained unknown until recent reports on the significance of mycofactocin in primary alcohol metabolism. Here, we show that transcript levels were increased in hypoxia-adapted M. tuberculosis; however, functionality was found likely dispensable for l-lactate metabolism. Targeted deletion of reduced the survival of M. tuberculosis in and hypoxia models but increased the bacterial growth in glucose-containing broth as well as in the lungs and spleens, albeit modestly, of aerosol-infected C57BL/6J mice. The cause of this growth advantage remains unestablished; however, the -deficient M. tuberculosis strain had reduced NAD(H)/NADP(H) levels and glucose-6-phosphate dehydrogenase activity with no impairment in phthiocerol dimycocerosate lipid synthesis. An ultrastructural examination of parental and mycofactocin biosynthesis gene mutants in M. tuberculosis, M. marinum, and M. smegmatis showed no altered cell morphology and size except the presence of outer membrane-bound fibril-like features only in a mutant subpopulation. A cell surface-protein analysis of M. smegmatis mycofactocin biosynthesis mutants with trypsin revealed differential abundances of a subset of proteins that are known to interact with mycofactocin and their homologs that can enhance protein aggregation or amyloid-like fibrils in riboflavin-starved eukaryotic cells. In sum, phenotypic analyses of the mutant strain implicate the significance of MftD/mycofactocin in M. tuberculosis growth and persistence in its host. Characterization of proteins with unknown functions is a critical research priority as the intracellular growth and metabolic state of Mycobacterium tuberculosis, the causative agent of tuberculosis, remain poorly understood. Mycofactocin is a peptide-derived redox cofactor present in almost all mycobacterial species; however, its functional relevance in M. tuberculosis pathogenesis and host survival has never been studied experimentally. In this study, we examine the phenotypes of an M. tuberculosis mutant strain lacking a key mycofactocin biosynthesis gene in and disease-relevant mouse models. Our results pinpoint the multifaceted role of mycofactocin in M. tuberculosis growth, hypoxia adaptation, glucose metabolism, and redox homeostasis. This evidence strongly implies that mycofactocin could fulfill specialized biochemical functions that increase the survival fitness of mycobacteria within their specific niche.
Topics: Adaptation, Physiological; Anaerobiosis; Animals; Bacterial Proteins; Biosynthetic Pathways; Female; Gene Expression Regulation, Bacterial; Male; Mice, Inbred C57BL; Mycobacterium tuberculosis; Peptides; Mice
PubMed: 34311585
DOI: 10.1128/mBio.01665-21 -
Tuberculosis (Edinburgh, Scotland) Dec 2014Mycobacterium tuberculosis is the causative agent of tuberculosis (TB) and second leading cause of human mortality due to a single infectious agent. This is mostly... (Review)
Review
Mycobacterium tuberculosis is the causative agent of tuberculosis (TB) and second leading cause of human mortality due to a single infectious agent. This is mostly because of M. tuberculosis' ability to adapt its metabolism to the host environment and regulate entry into and exit from cell cycle. Knowledge of the specific metabolic changes accompanying these transitions however is incomplete. Metabolomics has emerged as a new biochemical window into M. tuberculosis physiology. This review highlights recent insights from the application of such technologies to studies of the M. tuberculosis lifecycle.
Topics: Adaptation, Physiological; Biomarkers; Cell Cycle; Host-Pathogen Interactions; Humans; Metabolomics; Mycobacterium tuberculosis; Tuberculosis
PubMed: 25172023
DOI: 10.1016/j.tube.2014.08.002 -
Microbiology Spectrum Oct 2014Discontinuity of both strands of the chromosome is a lethal event in all living organisms because it compromises chromosome replication. As such, a diversity of DNA... (Review)
Review
Discontinuity of both strands of the chromosome is a lethal event in all living organisms because it compromises chromosome replication. As such, a diversity of DNA repair systems has evolved to repair double-strand DNA breaks (DSBs). In part, this diversity of DSB repair systems has evolved to repair breaks that arise in diverse physiologic circumstances or sequence contexts, including cellular states of nonreplication or breaks that arise between repeats. Mycobacteria elaborate a set of three genetically distinct DNA repair pathways: homologous recombination, nonhomologous end joining, and single-strand annealing. As such, mycobacterial DSB repair diverges substantially from the standard model of prokaryotic DSB repair and represents an attractive new model system. In addition, the presence in mycobacteria of a DSB repair system that can repair DSBs in nonreplicating cells (nonhomologous end joining) or when DSBs arise between repeats (single-strand annealing) has clear potential relevance to Mycobacterium tuberculosis pathogenesis, although the exact role of these systems in M. tuberculosis pathogenesis is still being elucidated. In this article we will review the genetics of mycobacterial DSB repair systems, focusing on recent insights.
Topics: DNA Breaks, Double-Stranded; DNA End-Joining Repair; DNA Repair Enzymes; Homologous Recombination; Mycobacterium tuberculosis; Recombinational DNA Repair; Virulence Factors
PubMed: 26104351
DOI: 10.1128/microbiolspec.MGM2-0024-2013