Legionella pneumophila
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ABSTRACT:
PROVIDER: PRJNA109915 | ENA |
REPOSITORIES: ENA
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Project description:Analysis of the human monocyte-derived macrophage (hMDM) transcriptional response to L. pneumophila infection at 8 hours post-infection We used microarrays to probe the hMDM transcriptional response to wild type L. pneumophila AA100 infection and its isogenic ankB and T2SS mutants. We identified up-regulation of innate immunity pathways and down-regulation of protein translation pathways
2014-09-19 | GSE61535 | GEO
Project description:Gene expression profiling of constitutively competent comR and proQ mutants and RNase R (rnr) mutant of L. pneumophila
| PRJNA110987 | ENA
Project description:Microarray analysis of Myd88-/-Trif-/- and Myd88-/-Rip2-/- macrophage responses to WT or dotA mutant L. pneumophila. Keywords: Expression profiling by microarray
2008-11-15 | GSE13147 | GEO
Project description:Analysis of the human monocyte-derived macrophage (hMDM) transcriptional response to L. pneumophila infection at 8 hours post-infection We used microarrays to probe the hMDM transcriptional response to wild type L. pneumophila AA100 infection and its isogenic ankB and T2SS mutants. We identified up-regulation of innate immunity pathways and down-regulation of protein translation pathways hMDMs were isolated from healthy donors and infected with L. pneumophila AA100 and its isogenic ankB and T2SS mutants for 8 h prior to isolation of total RNA and hybridization to Affymetrix microarrays.
2014-09-19 | E-GEOD-61535 | biostudies-arrayexpress
Project description:Legionella pneumophila are important opportunistic pathogens for which environmental reservoirs such as protists are crucial for the infection of humans. Free-living amoebae are considered key hosts providing nutrients and shelter for highly efficient intracellular proliferation of L. pneumophila, which eventually leads to lysis of the amoeba host cell. Yet, the significance of other bacterial players for L. pneumophila ecology is poorly understood. In this study we used a ubiquitous amoeba and their bacterial endosymbiont to investigate the impact of this common association on L. pneumophila infection. We demonstrate that Acanthamoeba castellanii harboring the chlamydial symbiont Protochlamydia amoebophila were able to erase L. pneumophila and, in contrast to symbiont-free amoebae, survived the infection and were able to resume growth. Environmental amoeba isolates harboring P. amoebophila were equally well-protected, and fresh environmental isolates of L. pneumophila were equally well-erased, suggesting ecological relevance of this symbiont-mediated protection. We further show that protection was not mediated by impaired L. pneumophila uptake. Instead, we observed reduced virulence of L. pneumophila released from symbiont-containing amoebae that is strongly supported by transcriptome data. Interference with transition to the transmissive phase is thus likely the basis for this protection. Finally, our data indicate that the defensive response of amoebae harboring P. amoebophila leaves the amoebae with superior fitness reminiscent of immunological memory. Given that mutualistic associations between bacteria and amoebae are widely distributed, P. amoebophila and potentially other amoeba endosymbionts could be key elements in shaping environmental survival, abundance and virulence of this important pathogen thereby affecting frequency of human infection.
2019-04-14 | GSE125876 | GEO
Project description:Legionella pneumophila is a gram-negative opportunistic human pathogen that infects and multiplies in a broad range of phagocytic protozoan and mammalian phagocytes. Based on the observation that small regulatory RNAs (sRNAs) play an important role in controlling virulence-related genes in several pathogenic bacteria, we attempted to test the hypothesis that sRNAs play a similar role in L. pneumophila. We used computational prediction followed by experimental verification to identify and characterize sRNAs encoded in the L. pneumophila genome. A 50-mer probe microarray was constructed to test the expression of predicted sRNAs in bacteria grown under a variety of conditions. This strategy successfully identified 22 expressed RNAs, out of which six were confirmed by northern blot and RACE. One of the identified sRNAs is highly expressed when the bacteria enter post exponential phase and computational prediction of its secondary structure reveals a striking similarity to the structure of 6S RNA, a widely distributed prokaryotic sRNA, known to regulate the activity of σ70-containing RNAP. A 70-mer probe microarray was used to identify genes affected by L. pneumophila 6S RNA in stationary phase. The 6S RNA encoded by the ssrS gene positively regulates expression of genes encoding type IVB secretion system effectors, stress response genes such as groES and recA as well as many genes with unknown or hypothetical functions. Deletion of 6S RNA significantly reduced L. pneumophila intracellular multiplication in both protist and mammalian host cells, but had no detectable effect on growth in rich media.
2010-01-01 | GSE19196 | GEO
Project description:Legionella pneumophila was exposed for 3h to 160 ug/ml of CuO nanoparticle. Untreated samples are used as the control condition.
2013-03-04 | GSE41966 | GEO
Project description:Legionella pneumophila cells were harvested during exponential growth (RP) and stationary growth (TP). VBNC cells were also anylzed. Protein subfractions were studied.
2015-11-13 | PXD001926 | Pride
Project description:Abstract Legionella pneumophila, the causative agent of Legionnaire’s disease, grows within macrophages and manipulates target cell signaling. Formation of a Legionella-containing replication vacuole requires the function of the bacterial type IV secretion system (Dot/Icm), which transfers protein substrates into the host cell cytoplasm. A global microarray analysis was used to examine the response of human macrophage-like U937 cells to low dose infections with L. pneumophila. The most striking change in expression was the Dot/Icm-dependent up-regulation of anti-apoptotic genes positively controlled by the transcriptional regulator NF-?B. Consistent with this finding, L. pneumophila triggered nuclear localization of NF-?B in human and mouse macrophage in a Dot/Icm-dependent manner. The mechanism of activation at low dose infections involved a signaling pathway that occurred independently of the TLR adaptor MyD88, and cytoplasmic sensor Nod1. In contrast, high MOI conditions caused a host cell response that masked the unique Dot/Icm-dependent activation of NF-?B. Inhibition of NF-?B translocation into the nucleus resulted in premature host cell death and termination of bacterial replication. In the absence of one anti-apoptotic protein, PAI-2, host cell death increased in response to L. pneumophila infection, indicating that induction of anti-apoptotic genes is critical for host cell survival. Keywords: time course, dose response
2006-08-17 | GSE5551 | GEO