Legionella pneumophila subsp. pneumophila str. Philadelphia 1
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PROVIDER: PRJNA343247 | ENA |
REPOSITORIES: ENA
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Project description:Legionella pneumophila transcriptome during intracellular multiplication in human macrophages
| PRJNA131851 | ENA
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:Transcriptome of Legionella pneumophila rpoS mutant in water
| PRJNA242832 | ENA
Project description:Legionella pneumophila is an intracellular pathogen that uses a type IV secretion system called Dot/Icm to translocate over 330 effector proteins into the infected cells. To explore the collective impact of Dot/Icm effectors on host cell processes, we created a library of 14 L. pneumophila genomic mutant strains lacking effector-rich regions (a total of 85 effector genes deleted) and used the multi-deletion mutants to interrogate host-pathogen interactions. We then performed bulk mRNAseq profilling of PMA-differentiated THP1 macrophages after infection with WT, Dot/Icm-deficient mutant, or genomic mutant strains of Legionella pneumophila 130b (18h post-infection, MOI 10).
2026-02-28 | E-MTAB-16655 | biostudies-arrayexpress
Project description:Legionella pneumophila is a Gram-negative facultative intracellular human pathogen with a distinct biphasic lifestyle. One of its primary environmental hosts in the free-living amoeba Acanthamoeba castellanii and its infection by L. pneumophila mimics that seen in human macrophages. Here we present analysis of strand specific sequencing of the transcriptional response of L. pneumophila in broth growth and in infection of A. castellanii.
2011-02-11 | GSE27232 | GEO
Project description:Legionella pneumophila subsp. pneumophila str. Philadelphia 1 Genome sequencing
| PRJNA195914 | ENA
Project description:Transcriptomic change of Legionella pneumophila in water.
| PRJNA268489 | ENA
Project description:Legionella pneumophila is a Gram-negative facultative intracellular human pathogen with a distinct biphasic lifestyle. One of its primary environmental hosts in the free-living amoeba Acanthamoeba castellanii and its infection by L. pneumophila mimics that seen in human macrophages. Here we present analysis of strand specific sequencing of the transcriptional response of L. pneumophila in broth growth and in infection of A. castellanii. Examination of 2 infection and 3 broth growth time points
2011-02-11 | E-GEOD-27232 | biostudies-arrayexpress
Project description:Legionella pneumophila is the causative agent of Legionnaires’ disease, an acute pulmonary infection. L. pneumophila is able to infect and multiply in both phagocytic protozoan, such as Acanthamoeba castellanii, and mammalian professional phagocytes. The best-known virulence determinant used by L. pneumophila to infect host cells is a Type IVb translocation system named Icm/Dot, which is used to modify the host cell functions to the benefit of the bacteria. To date the Icm/Dot systeme is known to translocate more than 100 effectors. While the transcriptional response of Legionella to the intracellular environement of A. castelannii as already been investigated, much less is known of how Legionella reacts transcriptionnally inside human macrophages. In this study, the transcriptome of L. pneumophila was monitored during exponential and post-exponential phase in rich AYE broth and during infection of human cultured macrophages by using microarray and a RNA amplification procedure called SCOTS to allow for the study of conditions of low bacterial loads. Among the genes induced intracellularly are those involved in amino acid synthesis pathway leading to L-arginine, L-histidne and L-proline as well as many transport system involved in amino acid and iron uptake. The Icm/Dot systems is not differentially expressed inside cells compare to the E phase control but the effectors are strongly induced. The intracellular transcriptome was further used to identify putative new Icm/Dot effectors and translocation was show to occur for 3 of them. This study provides a comprehensive view of how L. pneumophila react to the human macrophages intracellular environment.
2011-01-01 | GSE23029 | 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.
2014-12-04 | GSE56258 | GEO