The small regulatory RNA Lpr10 regulates the expression of RpoS in Legionella pneumophila
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ABSTRACT:
ORGANISM(S): Legionella pneumophila subsp. pneumophila Legionella pneumophila subsp. pneumophila str. Philadelphia 1
PROVIDER: GSE151162 | GEO | 2020/05/27
REPOSITORIES: GEO
Similar Datasets
Project description:Legionella pneumophila is a water-borne pathogen, and thus survival in the aquatic environment is central to its transmission to humans. Hence, identifying genes required for its survival in water could help prevent Legionnaires’ disease outbreaks. In the present study, we investigate for the first time the role of the sigma factor RpoS in promoting the survival in water, where L. pneumophila experiences total nutrient deprivation. The rpoS mutant showed a significant survival defect compared to the wild-type strain in defined water medium (DFM). Then, we analyzed the transcriptome of the rpoS mutant during exposure to water using whole genome microarray analysis. We found that RpoS negatively affects the expression of several genes, including genes required for replication, cell division, translation and transcription, suggesting that the mutant fails to shutdown major metabolic programs.
2014-12-04 | GSE56258 | GEO
Project description:Legionella pneumophila is a water-borne pathogen, and thus survival in the aquatic environment is central to its transmission to humans. Hence, identifying genes required for its survival in water could help prevent Legionnaires’ disease outbreaks. In the present study, we investigate for the first time the role of the sigma factor RpoS in promoting the survival in water, where L. pneumophila experiences total nutrient deprivation. The rpoS mutant showed a significant survival defect compared to the wild-type strain in defined water medium (DFM). Then, we analyzed the transcriptome of the rpoS mutant during exposure to water using whole genome microarray analysis. We found that RpoS negatively affects the expression of several genes, including genes required for replication, cell division, translation and transcription, suggesting that the mutant fails to shutdown major metabolic programs. The WT and rpoS mutant were grown to exponential phase in rich AYE broth, washed three times in DFM (NaCl 0.5 g/L, KH2PO40.2 g/L, KCl 0.5 g/L, pH=6.9) and resuspended in DFM at an OD600 of 0.1, After 24h exposure, RNA was extracted.
2014-12-04 | E-GEOD-56258 | biostudies-arrayexpress
Project description:Legionella pneumophila (Lp) is an opportunistic pathogen and its survival in water is critical for human infection. Therefore, identifying the genes of Lp that are required for survival in water may help devise strategies to prevent Legionella outbreaks. In this study, we exposed Lp in rich medium and in an artificial freshwater medium (Fraquil) for 2, 6 and 24 hours to uncover the global transcriptomic changes of Lp in water. The repression of major metabolic pathways, such as division, transcription and translation, suggests that Lp enters a dormant state in water. The induction of the flagellar associated genes (flg, fli and mot), enhance entry genes (enh) and some Icm/Dot effectors suggests that Lp may be waiting to establish intracellular replication in suitable host. Moreover, many genes involved in resistance to antibiotic and oxidative stress were induced, suggesting that Lp may be more tolerant to environmental stresses in water. Indeed, Lp exposed to water is more resistant to erythromycin, gentamycin and kanamycin than those cultured in rich medium. Apart from this, the gene bdhA involved in the degradation of the intracellular energy storage compound poly-hydroxybutyrate is highly expressed in water. Further characterization shows that bdhA is positively regulated by RpoS during short-term exposure to water. The deletion mutant of bdhA had a survival defect in water at 37°C, demonstrating that this gene is important for maintaining the long-term survivorship of Lp in water. Other identified genes highly induced upon exposure to water could also be necessary for Lp to survive in water.
2014-11-26 | GSE63622 | GEO
Project description:Legionella pneumophila (Lp) is an opportunistic pathogen and its survival in water is critical for human infection. Therefore, identifying the genes of Lp that are required for survival in water may help devise strategies to prevent Legionella outbreaks. In this study, we exposed Lp in rich medium and in an artificial freshwater medium (Fraquil) for 2, 6 and 24 hours to uncover the global transcriptomic changes of Lp in water. The repression of major metabolic pathways, such as division, transcription and translation, suggests that Lp enters a dormant state in water. The induction of the flagellar associated genes (flg, fli and mot), enhance entry genes (enh) and some Icm/Dot effectors suggests that Lp may be waiting to establish intracellular replication in suitable host. Moreover, many genes involved in resistance to antibiotic and oxidative stress were induced, suggesting that Lp may be more tolerant to environmental stresses in water. Indeed, Lp exposed to water is more resistant to erythromycin, gentamycin and kanamycin than those cultured in rich medium. Apart from this, the gene bdhA involved in the degradation of the intracellular energy storage compound poly-hydroxybutyrate is highly expressed in water. Further characterization shows that bdhA is positively regulated by RpoS during short-term exposure to water. The deletion mutant of bdhA had a survival defect in water at 37°C, demonstrating that this gene is important for maintaining the long-term survivorship of Lp in water. Other identified genes highly induced upon exposure to water could also be necessary for Lp to survive in water. Legionella pneumophila Philadelphia-1 strain JR32 was grown in AYE broth at 25°C shaking to OD600 of 1 in triplicate. Samples were taken for analysis; this is the control. Then the cultures were washed three times in Fraquil and resuspended in Fraquil to an OD600 of 1 and transfered to vessels of bioreactior (Biostat Q-plus). Samples were taken after 2h, 6h and 24h.
2014-11-26 | E-GEOD-63622 | biostudies-arrayexpress
Project description:Surviving the nutrient-poor aquatic environment for extended periods of time is important for transmission of various water-borne pathogen to the host, including Legionella pneumophila (Lp). Lp is a leading cause of community-acquired and nosocomial pneumonia called Legionnaires’ disease. The remarkable ability of the bacterium to survive in water for periods ranging from several months to years under starvation conditions alludes to regulatory pathways that mediate adaptation to the water environment. In the present study, we investigated a potential role for the LetA/LetS signal transduction system in the successful survival of Lp in water. During infection of host cells, the LetA/LetS two-component system controls the transition from the replicative phase to the transmissive phase in response to nutrient deprivation. In accordance with previous work, the letS mutant used in the present study is defective for pigment production and contributed to cell size reduction in the post-exponential phase. LetS also contributed to cell size reduction when Lp was exposed to water. Importantly, absence of the sensor kinase resulted in a significantly lower survival rate in water at various temperatures, as well as an increase sensitivity to heat shock. Transcriptomic analysis indicated that a general transcriptomic downshift of major pathways is orchestrated by LetA/LetS upon water exposure leading to better survival, suggesting a potential link with the stringent response. However, the expression of the LetA/S regulated small regulatory RNAs RsmY and RsmZ was not changed in a relAspoT mutant, which indicates that the stringent response and the LetA/S response are two distinct regulatory systems important for the survival of Lp in water.
2018-05-09 | GSE98743 | GEO
Project description:Extracellular vesicles (EVs) produced by bacteria, archaea and eukaryotic cells, are increasingly recognized as important mediators of intercellular communication via transfer of a wide variety of molecular cargoes. To characterize and identify the RNA molecules enriched in Legionella pneumophila extracellular vesicles (Lp-EVs) we performed RNAseq analyses. Four independent RNAseq libraries were constructed from RNA isolated from purified Lp-EVs and as control from the bacterial pellets, from which the Lp-EVs had been shed and deep sequenced using an Illumina platform. The sequences obtained from the Lp-EVs RNAseq libraries were compared to those obtained from the RNA extracted from the bacterial pellets (Figure 1g). The Lp-EV-sRNA cargo was defined as RNAs for which after normalization at least 1000 reads were sequenced and that showed an enrichment of a log2FC > 5 as compared to the RNAs from the bacterial pellets were. Using these parameters the analysis identified 47 different sRNAs enriched in the Lp-EVs. The 20 highest enriched sRNA that were present in all four biological replicates comprised 8 tRNAs, 7 sRNAs and 5 fragments of mRNA located in the CDS or UTR.
2021-12-06 | GSE159109 | GEO
Project description:Transcriptional profiling of L. pneumophila JR32 (wild-type) and rpoS- (LM1376) strains grown to stat phase compared to cultures grown to log phase Keywords: growth phase
2009-02-14 | GSE14830 | GEO
Project description:The intracellular pathogen Legionella pneumophila (Lp) is a strict aerobe, surviving and replicating in environments where it frequently encounters reactive oxygen species, such as the nutrient-poor water environment and inside host cells. In many proteobacteria, the oxidative stress response is regulated by the LysR-type regulator OxyR; however, the role played by the OxyR homologue in Lp is still unclear. Therefore, we undertook the characterisation of the phenotypes associated with the deletion of OxyR in Lp. OxyR is dispensable for growth in rich broth, in amoeba and in human cultured macrophages, and for the survival of Lp in water. Nevertheless, the mutant was found to be more sensitive to hydrogen peroxide than the wild-type when grown to post-exponential phase, but not when grown to exponential phase. Moreover, the mutant is defective in forming isolated colonies on charcoal yeast extract (CYE) agar plates, but supplementation with anti-ROS molecules, such as pyruvate, α-ketoglutarate and catalase, rescued this defect. Further characterisation of this phenotype using a transcriptional reporter fusion and microarray analysis revealed that the deletion mutant is not defective for the expression of known anti-ROS genes which suggests that the growth defect on agar plates and the higher susceptibility to hydrogen peroxide are due to a broad change in the transcriptional response. Furthermore, the growth defect is suppressed when the mutant is grown on CYE plates made with agarose, suggesting that a compound present in typical agar is toxic for the oxyR mutant.
2021-07-20 | GSE87029 | GEO
Project description:Outbreak of Legionnaires’ Disease - Calgary 2012
| PRJNA291490 | ENA
Project description:Transcriptome of Legionella pneumophila rpoS mutant in water
| PRJNA242832 | ENA