Comparison of gene expression in M. tuberculosis TrxB2-TetON-tetO-WT mutant treated or not with atc
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ABSTRACT: 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: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.
Project description:We sequenced mRNA from Mtb that had been treated with 5 mM nitrate or was untreated in standard 7H9/ADNaCl medium. This generated the first analysis of gene expression following mycobacterial nitrate respiration. Examination of mRNA levels in Mtb following nitrate respiration, which results in the production of nitrite.
Project description:Goal: Assess transcriptional changes in Mtb associated with activation of adenylyl cyclase activity in the bacterium, by treatment with the Rv1625c agonist V-59 or activation of the TetOn-cAMP construct. Specifically, address changes in transcription of cholestrrol utilization genes, during growth of Mtb in cholesterol media. Method: WT, Rv1625c knockout, and Rv1625c Complement strains of Mtb were grown in cholesterol-based media and treated with V-59 or vehicle control (DMSO). V-59 is known to increase cAMP synthesis in WT, but not in Rv1625c knockout Mtb. V-59 increases cAMP synthesis above that observed in WT in the Complement strain, due to Rv1625c overexpression in this strain. Also, utilized TetOn-cAMP Mtb strain, to induce cAMP synthesis independent of V-59 and Rv1625c. Treatment with Atc induces expression of catalytic domain of Rv1264 in this strain. We grew the TetOn-cAMP strain in cholesterol-based media, treated with Atc or EtOH (vehicle control). Conclusions: Transcriptional changes to cholesterol utilization genes associated with V-59 treatment in WT Mtb were similar to those associated with TetOn-cAMP induction. The transcriptional changes associated with blockade of cholesterol degradation following V-59 treatment in WT Mtb were not observed in the Rv1625c knockout strain. The Rv1625c knockout strain had intrinsic defects in induction of cholesterol utilization genes. The Complement strain showed enhanced transcriptional changes in response to V-59 treatment.
Project description:The purpose of this study was to examine how ethoxzolamide modulates gene M. tuberculosis gene expression at acidic pH. We observed that ethoxzolamide downregulates genes of the PhoPR regulon. Mtb strain CDC1551 was grown at 37C in T-25 vented, standing tissue culture flasks in 8 ml of buffered 7H9 medium seeded an initial OD of 0.2. Three conditions were examined with two biological replicates: 1) DMSO treated, pH 7.0, 2) DMSO treated, pH 5.7, 3) 40 µM ethoxzolamide treated, pH 5.7. The CDC1551(phoP::Tn) mutant was grown in a similar manner and treated with DMSO at pH 7.0 and 5.7. Following six days incubation, total bacterial RNA was extracted and analyzed as previously described.
Project description:Transcriptional profile of esx-3 conditional mutant strain (TB79) vs its parental strain (TB38) grown in 7H9 in presence of 100ng/ml Atc for 48h One experimental condition. 2 independent biological replicates. One replicate per array.
Project description:Mtb appears to have developed specialized biomolecular infrastructure to survive and persist within granulomas, where it is subjected to a diverse set of stress conditions. One of these stress conditions is hypoxia. We hypothesized that host cell response is radically altered with hypoxia stressed Mtb and designed in-vitro experiments to study this phenomenon. Hypoxia-stressed as well as aerobically grown Mtb were used to infect rhesus macaque bone marrow derived macrophages (Rh-BMDMs) and the host global transcriptional response compared. Using 4 x44 k Agilent arrays specific for rhesus macaque genome, we tested in biological duplicate the effect of aerogically grown Mtb on rhesus macaque BMDMs and compared this to the corresponding effect of the hypoxia-conditioned Mtb on rhesus macaque BMDMs
Project description:CD8+ T cells contribute to protective immunity to Mycobacterium tuberculosis (Mtb), but the principles that govern presentation of Mtb peptides on MHC class I (MHC-I) on the surface of infected macrophages for CD8+ T cell recognition are incompletely understood. Here, we use internal standard parallel reaction monitoring (IS-PRM, also known as SureQuant) to rigorously validate identifications of Mtb-derived MHC-I peptides obtained in data-dependent MS analyses. We further use SureQuant to quantify presentation of Mtb peptides derived from the secreted effector proteins EsxA and EsxJ across multiple experimental conditions. We show that presentation of both EsxA- and EsxJ-derived peptides requires the activity of the mycobacterial ESX-1 type VII secretion system, possibly indicating that ESX-1-mediated phagosome membrane damage allows Mtb proteins to access MHC-I antigen processing pathways. We show that this requirement is independent of type I interferon signaling that occurs downstream of phagosome damage. Treatment with inhibitors of conventional proteolytic pathways involved in MHC-I antigen processing inhibits presentation of self peptides as expected, but does not inhibit presentation of Mtb peptides, implying an alternative or redundant mechanism of processing.