Early response of Coxiella burnetii to temperature stress
Ontology highlight
ABSTRACT:
ORGANISM(S): Coxiella burnetii
SUBMITTER: Kevin Lebrigand
PROVIDER: E-GEOD-21778 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Genotyping based on genomic comparative hybridization of different isolates of coxiella burnetii compared to NMI reference strain Two-condition experiment, NMI vs. isolates. One replicate per isolate.
2011-12-31 | E-GEOD-31543 | biostudies-arrayexpress
Project description:Transcriptional profiling of Coxiella burnetii phase I (RSA 493) submitting either to Cold and Heat shock comparing to control untreated Coxiella burnetii phase I (RSA 493) grown at 35°C.
2011-01-01 | GSE21778 | GEO
Project description:Coxiella burnetii, the agent of Q fever, persists in humans despite specific immune responses: however, its reservoir remains unknown. We detected C. burnetii in adipose tissue from BALB/c and C57/BL6 mice 4 months after infection when no bacteria were found in other tissues. C. burnetii infected cultivated adipocytes, replicated within late phagosomes and induced a transcriptional program that was enriched for the expression of genes associated with inflammatory response, hormonal responses and cytoskeleton. 3T3-L1 (ATCC) differentiated adipocytes were stimulated or not with Coxiella burnetii (NMI) at a ratio of 50 bacteria per cell. Four biological replicates were analyzed in each group. Due to technical reason, one unstimulated sample was discarded from the analysis.
2014-05-25 | E-GEOD-46335 | biostudies-arrayexpress
Project description:A hallmark of Coxiella burnetii, the bacterial cause of human Q fever, is a biphasic developmental cycle that generates biologically, ultrastructurally, and compositionally distinct large cell variant (LCV) and small cell variant (SCV) forms. LCVs are replicating, exponential phase forms while SCVs are non-replicating, stationary phase forms. The SCV has several properties, such as a condensed nucleoid and an unusual cell envelope, suspected of conferring enhanced environmental stability. To identify genetic determinants of the LCV to SCV transition, we profiled the C. burnetii transcriptome by microarray at 3 (early LCV), 5 (late LCV), 7 (intermediate forms), 14 (early SCV) and 21 days (late SCV) post-infection (PI) of Vero epithelial cells. Relative to early LCV, genes down-regulated in the SCV were primarily involved with intermediary metabolism. Up-regulated SCV genes included those involved in oxidative stress responses, arginine acquisition, and cell wall remodeling. A striking transcriptional signature of the SCV was induction (>7-fold) of five genes encoding predicted L,D transpeptidases that catalyze nonclassical 3-3 peptide cross-links in peptidoglycan (PG), a modification that can influence several biological traits in bacteria. Accordingly, of cross-links identified, muropeptide analysis showed PG of SCV with 46% 3-3 cross-links as opposed to 16% 3-3 cross-links for LCV. Moreover, cryo-electron microscopy revealed SCV with an unusually dense periplasmic layer that was intimately associated with the outer membrane. In contrast, LCV had a clearly distinguishable periplasm and inner/outer membranes. Collectively, these results indicate the SCV produces a unique transcriptome with a major component directed towards remodeling a PG layer that likely contributes to Coxiella's environmental resistance. Coxiella Vero time series. Coxiella was profiled at day 3, day 5, day 7, day 14 and day 21 post-infection of Vero epithelial cells.
2016-02-10 | E-GEOD-74489 | biostudies-arrayexpress
Project description:The inability to propagate obligate intracellular pathogens under axenic (host cell-free) culture conditions imposes severe experimental constraints that have negatively impacted progress in understanding pathogen virulence and disease mechanisms. Coxiella burnetii, the causative agent of human Q (Query) fever, is an obligate intracellular bacterial pathogen that replicates exclusively in an acidified, lysosome-like vacuole. To define conditions that support C. burnetii growth, we systematically evaluated the organismâ??s metabolic requirements using expression microarrays, genomic reconstruction, and metabolite typing. This led to development of a complex nutrient medium that supported substantial growth (~ 3 log10) of C. burnetii in a 2.5% oxygen environment. Importantly, axenically grown C. burnetii were highly infectious for Vero cells and exhibited developmental forms characteristic of in vivo grown organisms. Axenic cultivation of C. burnetii will facilitate studies of the organismâ??s pathogenesis and genetics, and aid development of Q fever preventatives such as an effective subunit vaccine. Furthermore, the systematic approach used here may be broadly applicable to development of axenic media that support growth of other medically important obligate intracellular pathogens. Host cell-free growth, Vero cell growth and carryover baseline of Coxiella burnetii
2010-06-20 | E-GEOD-13338 | biostudies-arrayexpress
Project description:The formation of granulomas is associated with the resolution of Q fever, a zoonosis due to Coxiella burnetii; however the molecular mechanisms of granuloma formation remain poorly understood. We generated human granulomas with peripheral blood mononuclear cells and beads coated with C. burnetii, using BCG extracts as controls. A microarray analysis showed dramatic changes in gene expression in granuloma cells compared with peripheral blood mononuclear cells. About 60% of modulated genes were common to C. burnetii and BCG granulomas including M1-related genes. C. burnetii granulomas also expressed a specific transcriptional profile that was essentially enriched in genes associated with type I interferon response (IFI44, IFI44L, IFI6, OAS1, OAS2, OAS3, ISG15, IFIT1, IFITM2, IFITM3, MX1 and MX2). Real-time RT-PCR confirmed that C. burnetii especially increased the expression of interferon-stimulated genes in granulomas generated from controls or Q fever patients. Our results showed that granuloma formation is associated with a core of transcriptional response, but that the granulomatous response to C. burnetii is characterized by the activation of type I interferon-related genes, conferring a new role for type I interferon response in the control of C. burnetii infection. Human Peripheral Blood Mononuclear Cells (PBMC) were co-cultured with beads coated with Mycobacterium bovis strain Bacille Calmette Guerin (BCG) extracts or Coxiella burnetii (C.burnetii) extracts for 8 days and PBMC at day 0 were used as controls. For each condition ( unstimulated, BCG and C.burnetii), each microarray is a replicate of the same biological sample.
2015-05-01 | E-GEOD-37666 | biostudies-arrayexpress
Project description:Analysis of genetic diversity of 25 Coxiella burnetii isolates with relative to the Nine Mile (RSA493) reference isolate.
2006-10-30 | E-TABM-35 | biostudies-arrayexpress
Project description:Q fever is due to Coxiella burnetii, an obligate intracellular bacterium. We investigated the mechanism of establishment of chronic form of the Q fever that mainlym anifested by endocarditis. We showed that patients with acute Q fever and valvulopathy, who have the higher risk to develop an endocarditis, exhibited high levels of circulating apoptotic cells. We further investigated the effect of the uptake of dead cells on the intracellular fate of the bacterium and the immune response of monocytes and macrophages.
2008-10-09 | E-MEXP-1289 | biostudies-arrayexpress
Project description:Coxiella burnetii undergoes a biphasic developmental cycle within its host cell that generates morphologically and physiologically distinct large cell variants (LCV) and small cell variants (SCV). During the lag phase of the C. burnetii growth cycle, non-replicating SCV differentiate into replicating LCV that in turn differentiate back into SCV during stationary phase. Nearly homogeneous SCV are observed in infected Vero cells after extended incubation (21 to 28 days). In the current study, we sought to establish whether C. burnetii developmental transitions in host cells are recapitulated during host cell-free (axenic) growth in first and second generation acidified citrate cysteine media (ACCM-1 and ACCM-2, respectively). We show that ACCM-2 supported developmental transitions and viability. Although ACCM-1 also supported SCV to LCV transition, LCV to SCV transition did not occur after extended incubation (21 days). Instead, C. burnetii exhibited a ghost-like appearance with bacteria containing condensed chromatin but otherwise devoid of cytoplasmic content. This phenotype correlated with a near total loss in viability between 14 and 21 days of cultivation. Transcriptional profiling of C. burnetii following 14 days of incubation revealed elevated expression of oxidative stress genes in ACCM-1 cultivated bacteria. ACCM-2 differs from ACCM-1 by the substitution of methyl-b-cyclodextrin (Mb-CD) for fetal bovine serum. Addition of Mb-CD to ACCM-1 at 7 days post-inoculation rescued C. burnetii viability and lowered expression of oxidative stress genes. Thus, Mb-CD appears to alleviate oxidative stress in ACCM-2 to result in C. burnetii developmental transitions and viability that mimic host cell-cultivated organisms. Axenic cultivation of C. burnetii in ACCM-2 and new methods Coxiella axenic media 1 vs 2
2013-12-02 | E-GEOD-51135 | biostudies-arrayexpress
Project description:Coxiella burnetii, a category B select agent, is endemic worldwide, except New Zealand. It causes annually several outbreaks of the zoonotic disease Q fever predominantly in small ruminants. To date, the lipopolysaccharide (LPS), besides a type IV secretion system (T4SS), is the only defined and characterized virulence determinant of C. burnetii. This surface molecule is used to distinguish between virulent (Ph I) and low-virulent (Ph II) organisms, the latter emerge only after frequent passaging in the laboratory. As an obligate intracellular pathogen, targeted genetic modification is still not a routine and labour intensive procedure. The deeper study of novel determinants is complicated and demands not only advanced techniques for axenic and for cell culture-based cultivation but also novel approaches in the high-resolution mass spectrometry. This work is the first proteomic study comparing. C. burnetii Ph I and Ph II propagated in different axenic media and in cell culture.
2019-10-24 | PXD013224 | Pride