Project description:M. tuberculosis thioredoxin reductase (TrxB2) is essential for Mtb physiology and pathogenesis. To gain insight into its biological functions, we generated the TrxB2-TetON-tetO mutants, in which TrxB2 is partially depleted in the absence of atc without impairing bacterial viability. We grew TrxB2-TetON-tetO-WT in 7H9 medium with 400 ng/ml atc, until the OD reached 0.5~0.6. Then Mtb was washed with 7H9 medium 3 times and suspended in 7H9 medium with or without atc. Then samples were taken 24, 48, 72 and 120 hrs later.
Project description:M. tuberculosis thioredoxin reductase (TrxB2) is essential for bacterial survival in vitro and in vivo. To gain insight into the mechanisms underlying lethality caused by TrxB2 depletion, we compared the mRNA profiles of TrxB2-DUC mutant in the presence and absence of atc. We grew bacteria in 7H9 medium to an OD of 0.5~0.6 and then added atc to a final concentration of 400ng/ml. Samples were collected 6 h and 24 h after atc treatment.
Project description:M. tuberculosis thioredoxin reductase (TrxB2) is essential for bacterial survival in vitro and in vivo. To gain insight into the pathways dependent on TrxB2, we compared the mRNA profiles of TrxB2-DUC mutant in the presence and absence of atc and DTT. We grew bacteria in 7H9 medium to an OD of 0.5~0.6. We then added atc to a final concentration of 800 ng/ml and DTT to a final concentration of 2 mM. Samples were collected 24 hr after treatment.
Project description:Comparison of gene expression profile of the whiB4 mutant strain of Mycobacterium tuberculosis with the wild type Mycobacterium tuberculosis H37RV Mtb WhiB4 mutant mRNA was compared with the mRNA of wtMtb H37RV under aerobic conditons Aerbic conditions OD600 nm of 0.4, MtbWhiB4KO vs wtMtb, biological replicates: 3 wt Mtb H37RV and 3 MtbWhiB4 KO
Project description:The bacteriostatic and bactericidal effects and the corresponding expression profiles of Mycobacterium tuberculosis to representative oxidative and nitrosative stresses were investigated by growth and survival studies and whole genome expression analysis. The response of M. tuberculosis to a range of hydrogen peroxide (H2O2) concentrations tended to fall into three distinct categories: (1) low level exposure resulted in induction of few H2O2 sensitive genes, (2) intermediate exposure resulted in massive transcriptional changes without an effect on growth or survival, and (3) high exposure resulted in a muted transcriptional response and eventual death. Nitric oxide (NO) exposure initiated much of the same transcriptional response as H2O2. However, unlike H2O2 exposure, NO exposure affected a dose-dependent bacteriostatic activity without killing and induction of dormancy-related genes. Included in the shared response to H2O2 and NO was the induction of genes encoding oxidative stress detoxification and iron-sulfur cluster repair functions. Expression of several key oxidative stress defense genes was constitutive, or increased moderately from an already elevated level, suggesting bacilli that are continually primed for oxidative stress defense. Deletion of the known oxidative stress responsive regulator, FurA, resulted in the constitutive expression of furA, katG, and Rv1907c; while other genes do not appear to be solely controlled by FurA. In contrast to Escherichia coli, M. tuberculosis appears highly resistant to DNA damage-dependent killing caused by low mill molar levels of H2O2. Furthermore, instead of limiting access to iron to prevent hydroxyl radical formation from H2O2 and thus DNA damage, M. tuberculosis induced iron uptake genes in response to H2O2 and NO. Set of arrays that are part of repeated experiments Compound Based Treatment: H2O2 or DETA/NO treatment
Project description:The mycobacterial IdeR protein is a metal-dependent regulator of the DtxR (diphtheria toxin repressor) family. In the presence of iron, it binds to a specific DNA sequence in the promoter regions of the genes that it regulates, thus controlling their transcription. In this study, we provide evidence that ideR is an essential gene in Mycobacterium tuberculosis. ideR cannot normally be disrupted in this mycobacterium in the absence of a second functional copy of the gene. However, a rare ideR mutant was obtained in which the lethal effects of ideR inactivation were alleviated by a second-site suppressor mutation and which exhibited restricted iron assimilation capacity. Studies of this strain and a derivative in which IdeR expression was restored allowed us to identify phenotypic effects resulting from ideR inactivation. Using DNA microarrays, the iron-dependent transcriptional profiles of the wild-type, ideR mutant, and ideR complemented mutant strains were analyzed, and the genes regulated by iron and IdeR were identified. These genes encode a variety of proteins, including putative transporters, proteins involved in siderophore synthesis and iron storage, members of the PE/PPE family, a membrane protein involved in virulence, transcriptional regulators, and enzymes involved in lipid metabolism.
Project description:This SuperSeries is composed of the following subset Series: GSE6209: The global transcriptional profile of Mycobacterium tuberculosis during human macrophages infection GSE7962: Sigma factor E of Mycobacterium tuberculosis controls the expression of bacterial components that modulate macrophages Keywords: SuperSeries Refer to individual Series
Project description:Mycobacterium tuberculosis, a pathogen of global importance, utilizes the ESX-1 protein secretion system to export virulence factors that disarm host macrophages. Although this secretory pathway is critical for virulence, how ESX-1 is regulated is completely unknown. Here we show that EspR (Rv3849) is a key regulator of ESX-1. EspR activates transcription of an operon that includes three ESX-1 components, Rv3616c-Rv3614c, whose expression in turn promotes secretion of ESX-1 substrates. Keywords: Strain comparison Comparison of the global gene expression of four M.tb strains grown in log phase: Erdman strain of M.tb, espR transposon mutant, the espR transposon mutant complemented with the wild type copy of the espR gene, and the espR transposon mutant complemented with an N-terminal FLAG espR gene.