Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

In vitro dormancy achieved by multiple stresses in Mycobacterium tuberculosis

ABSTRACT: The human pathogen, Mycobacterium tuberculosis, develops a dormant infection, in which organisms survive within the body. We established a unique in vitro dormancy model based on the characterization of drug-resistance to INH and rifampin. M. tuberculosis cells were maintained in controlled and defined multiple stress conditions with low oxygen (5% dissolved oxygen tension), acid (pH 5.) along with glycerol-deprived medium conditions. To monitor gene expression changes in M. tuberculosis in response to the multiple stresses, we performed microarray analysis at the time point of 1, 2, 3, 6, and 12days after treatment. M. tuberculosis adapting to multiple stresses displayed characteristics associated with persistence in vivo, including entry into a non-replicative state and the repression of genes involved in energy regeneration. Under in vitro multiple-stresses, M. tuberculosis significantly modulated gene expression mainly in response to the starvation stresses. Cells exposed to these multiple stress conditions shows significant drug-resistance. Comparison with other in vivo expression profiles demonstrates induction of several common genes for in vitro dormancy conditions. Keywords: Stress response in time course. Samples under multiple stress condition were taken at day 1, 2, 3, 6, and 12 for microarray hybridization. More than two technical replicates per biological samples with Cy3/5 dye-swaps.

ORGANISM(S): Mycobacterium tuberculosis H37Rv

SUBMITTER: ChangMuk Lee

PROVIDER: E-GEOD-10391 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

A novel in vitro multiple-stress dormancy model for Mycobacterium tuberculosis generates a lipid-loaded, drug-tolerant, dormant pathogen.

Deb Chirajyoti C Lee Chang-Muk CM Dubey Vinod S VS Daniel Jaiyanth J Abomoelak Bassam B Sirakova Tatiana D TD Pawar Santosh S Rogers Linda L Kolattukudy Pappachan E PE

PloS one 20090629 6

<h4>Background</h4>Mycobacterium tuberculosis (Mtb) becomes dormant and phenotypically drug resistant when it encounters multiple stresses within the host. Inability of currently available drugs to kill latent Mtb is a major impediment to curing and possibly eradicating tuberculosis (TB). Most in vitro dormancy models, using single stress factors, fail to generate a truly dormant Mtb population. An in vitro model that generates truly dormant Mtb cells is needed to elucidate the metabolic require ...[more]

PMID: 19562030

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Project description:Furfural is the prevalent microbial inhibitor generated during pretreatment and hydrolysis of lignocellulosic biomass to monomeric sugars, but the molecular response of Clostridium beijerinckii NCIMB 8052 to this compound is unknown. To discern the effect of furfural on C. beijerinckii and to gain insights into the molecular mechanisms of action and detoxification, we studied the physiological changes of furfural-stressed cultures during acetone-butanol-ethanol (ABE) fermentation, and profiled differentially expressed genes by genome-wide transcriptional analysis. C. beijerinckii exposed to furfural stress during the acidogenic growth phase produced 13% more ABE than the unstressed control. The growth and ABE by C. beijerinckii ceased following exposure to furfural stress during the solventogenic growth phase. By comparing gene expression of furfural-stressed cultures to that of the unstressed control, at both the acidogenic and solventogenic phases, we ascertained that furfural induces expression of several genes including those that code for heat shock proteins, redox enzymes and cofactor associated proteins, and ATP-binding cassette transporters, and represses genes belonging to the phosphotransferase system, two-component system, chemotaxis and cell motility. Based on these results, we discuss the underpinning for furfural-mediated change in ABE fermentation by the solventogenic Clostridium species. C. beijerinckii 8052 pre-culture was incubated anaerobically to attain acidogenic or solventogenic growth phase. The culture was then subdivided into two bottles. One bottle was challenged with furfural and the other bottle was left unchallenged. After 3 h growth, C. beijerinckii 8052 samples were collected, during which the original concentration of furfural in the growth medium was reduced to more than half. Total RNA was isolated, purified, converted to enriched mRNA, and dye-coupled (Alexa Fluor 555) complementary cRNA. This was followed by hybridization and microarray data analysis.

Project description:Background: A significant body of evidence accumulated over the last century suggests a link between hypoxic microenvironments within the infected host and the latent phase of tuberculosis. Studies to test this correlation have identified the M. tuberculosis initial hypoxic response, controlled by the two-component response regulator DosR. The initial hypoxic response is completely blocked in a dosR deletion mutant. Methodology/Principal Findings: We show here that a dosR deletion mutant enters bacteriostasis in response to in vitro hypoxia with only a relatively mild decrease in viability. In the murine infection model, the phenotype of the mutant was indistinguishable from that of the parent strain. These results suggested that additional genes may be essential for entry into and maintenance of bacteriostasis. Detailed microarray analysis of oxygen starved cultures revealed that DosR regulon induction is transient, with induction of nearly half the genes returning to baseline within 24 hours. In addition, a larger, sustained wave of gene expression follows the DosR-mediated initial hypoxic response. This Enduring Hypoxic Response (EHR) consists of 230 genes significantly induced at four and seven days of hypoxia but not at initial time points. These genes include a surprising number of transcriptional regulators that could control the program of bacteriostasis. We found that the EHR is independent of the DosR-mediated initial hypoxic response, as EHR expression is virtually unaltered in the dosR mutant. Conclusions/Significance: Our results suggest a reassessment of the role of DosR and the initial hypoxic response in MTB physiology. Instead of a primary role in survival of hypoxia induced bacteriostasis, DosR may regulate a response that is largely optional in vitro and in mouse infections. Analysis of the EHR should help elucidate the key regulatory factors and enzymatic machinery exploited by M. tuberculosis for long-term bacteriostasis in the face of oxygen deprivation. Keywords: time-course Each hypoxic timecourse compared to the matching log phase sample. Each time point/strain represented by a minimum of three replicates.

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Dataset Information

In vitro dormancy achieved by multiple stresses in Mycobacterium tuberculosis

Publications

A novel in vitro multiple-stress dormancy model for Mycobacterium tuberculosis generates a lipid-loaded, drug-tolerant, dormant pathogen.

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