Project description:Background. The Beijing family of Mycobacterium tuberculosis is dominant in countries in East Asia. Genomic polymorphisms are a source of diversity within the M.tuberculosis genome and may account for the variation of virulence among M.tuberculosis isolates. To date there are no studies that have examined the genomic composition of M.tuberculosis isolates from the high TB-burden country, Myanmar. Methodology/Principle findings. Twenty-two M.tuberculosis isolates from Myanmar were screened on whole-genome arrays containing genes from M.tuberculosis H37Rv, M.tuberculosis CDC1551 and M.bovis AF22197. Screening identified 198 deletions or extra regions in the clinical isolates compared to H37Rv. Twenty-two regions differentiated between Beijing and non-Beijing isolates and were verified by PCR on an additional 40 isolates. Six regions (Rv0071-0074 [RD105], Rv1572-1576c [RD149], Rv1585c-1587c[RD149], MT1798-Rv1755c [RD152], Rv1761c [RD152] and Rv0279c) were deleted in Beijing isolates, of which 4 (Rv1572-1576c, Rv1585c-1587c, MT1798-Rv1755c and Rv1761c) were variably deleted among ST42 isolates, indicating a closer relationship between the Beijing and ST42 lineages. The TbD1 region, Mb1582-Mb1583 was deleted in Beijing and ST42 isolates. One M.bovis gene of unknown function, Mb3184c was present in all isolates, except 11 of 13 ST42 isolates. The CDC1551 gene, MT1360 coding for a putative adenylate cyclase, was present in all Beijing and ST42 isolates (except 1). The pks15/1 gene, coding for a putative virulence factor, was intact in all Beijing and non-Beijing isolates, except in ST42 and ST53 isolates. Conclusion. This study describes previously unreported deletions/extra regions in Beijing and non-Beijing M.tuberculosis isolates. The modern and highly frequent ST42 lineage showed a closer relationship to the hypervirulent Beijing lineage than to the ancient non-Beijing lineages. The pks15/1 gene was disrupted only in modern non-Beijing isolates. This is the first report of an in-depth analysis on the genomic diversity of M.tuberculosis isolates from Myanmar. Data is also available from http://bugs.sgul.ac.uk/E-BUGS-66
Project description:Transcriptional profile comparison among Beijing and non-Beijing M. tuberculosis isolates. Three M. tuberculosis strains were compared. The laboratory reference strain, H37Rv, belongs to the Euro-American or lineage 4. Two clinical isolates of the East-Asian or lineage 2: 98_1663 is a pre-Beijing or Group 1 isolate, and HN878 is a Beijing or Group 5 isolate. Three replicates were performed for each comparison using two different biological samples.
Project description:While persistence in a dormant state is crucial for the life cycle of Mycobacterium tuberculosis, no investigation regarding dormancy survival of different strains across different lineages was performed so far. We analyzed responses to oxygen starvation and recovery in terms of growth, metabolism and transcription. All different strains belonging to the (Euro-American) lineage (L4) showed similar survival and resuscitation characteristics. Different clinical isolates from the Beijing (L2) , East African-Indian (L3), and Delhi/Central Asian (L1) did not survive oxygen starvation. We show that dormancy survival is lineage-dependent. Recovery from O2 starvation was observed in Euro-American (L4) but no other used strains (L1, L2, L3). Thus, resuscitation from dormancy after oxygen starvation is not a general feature of all M. tuberculosis strains as thought before. Our findings are of key importance to understand infection dynamics of non-Euro American vs Euro American strains and to develop drugs targeting the dormant state.
Project description:While persistence in a dormant state is crucial for the life cycle of Mycobacterium tuberculosis, no investigation regarding dormancy survival of different strains across different lineages was performed so far. We analyzed responses to oxygen starvation and recovery in terms of growth, metabolism and transcription. All different strains belonging to the (Euro-American) lineage (L4) showed similar survival and resuscitation characteristics. Different clinical isolates from the Beijing (L2) , East African-Indian (L3), and Delhi/Central Asian (L1) did not survive oxygen starvation. We show that dormancy survival is lineage-dependent. Recovery from O2 starvation was observed in Euro-American (L4) but no other used strains (L1, L2, L3). Thus, resuscitation from dormancy after oxygen starvation is not a general feature of all M. tuberculosis strains as thought before. Our findings are of key importance to understand infection dynamics of non-Euro American vs Euro American strains and to develop drugs targeting the dormant state.
Project description:Mycobacterium tuberculosis is the causitive agent of TB, which is a global epidemic that has claimed millions of lives. Some clinical strains of M.tb have significantly more severe clinical outcomes, while some other mycobacteria ordinarily do not cause disease in humans. The biological processes underpinning this difference are poorly understood. Thus, this project aimed to identify proteomic differences between more virulent strains of the MTBC (Beijing, J37Rv, CAS and LAM) vs those strains that only cause disease in severely immune compromised humans (Bovis, Smegmatis and Avium). We hypothesise that these differences may offer insight into the molecular mechanisms by which M.tb has become more virulent by evading drug treatment or evading the host immune system more effectively.
Project description:Glycoproteomics is likely to identify Mtb virulence factors because glycoproteins on the bacterial cell envelope are used by mycobacteria to enter the primary human host cell, the macrophage. It has been proposed that Mtb interacts with mannose receptors on host cells via mannosylated proteins to enter the macrophages. Despite the vital importance of these proteins in Mtb pathogenesis, our current knowledge of Mtb glycoproteins is still limited, and only a few secreted and cell wall-associated glycoproteins have to date been described. Previous studies have used laboratory strains as model systems to study glycosylation in Mtb. However, only a few sub-groups within the genetically conserved MTBC appear to cause extensive outbreaks with different clinical presentation and AMR. In this study, we employed qualitative and quantitative mass spectrometry and bioinformatics to explore the glycoproteomic patterns of clinical isolates from four lineages of the MTBC, lineages 3, 4, 5 and 7, to investigate the role of protein glycosylation in Mtb adaptation, survival and AMR.