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.
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. Four experiments : Cold shock 30 min Vs 35°C; Cold shock 60 min Vs 35°C; Heat shock 30 min Vs 35°C; Heat shock 60 min Vs 35°C 3 biological replicates, independently grown and harvested. Four replicate per array.
Project description:Coxiella burnetii is a Gram-negative intracellular pathogen that causes the debilitating disease Q fever, which affects both animals and humans. The only available vaccine, Q-Vax, is effective but has a high risk of severe adverse reactions, limiting its use as a countermeasure to contain outbreaks. Therefore, it is essential to identify new drug targets to treat this infection. Macrophage infectivity potentiator (Mip) proteins catalyze the folding of proline-containing proteins through their peptidyl prolyl cis-trans isomerase (PPIase) activity and have been shown to play an important role in the virulence of several pathogenic bacteria but to date its role in C. burnetii pathogenesis has not been investigated. This study demonstrates that CbMip is likely to be an essential protein in C. burnetii. Pipecolic acid derived compounds, SF235 and AN296 demonstrate inhibitory activities against CbMip and these compounds were found to significantly inhibit intracellular replication of C. burnetii in both HeLa and THP-1 cells. Furthermore, SF235 and AN296 were also found to exhibit antibiotic properties against both the virulent (Phase I) and avirulent (Phase II) forms of C. burnetii Nine Mile Strain RSA439 in axenic culture with comparative proteomic demonstrating selective alterations in response to these agents. This study also showed that exposure of C. burnetii to Mip inhibitors resulted in increased sensitivity to oxidative stress. Furthermore, compounds SF235 and AN296 demonstrated protective activity in vivo and significantly improved the survival of Galleria mellonella infected with C. burnetii. These results suggest that unlike in other bacteria, Mip in C. burnetii is required for growth and replication and that inhibitors against CbMip offer potential as novel therapeutics against C. burnetii.
Project description:A comparison was made between the THP-1(Human monocytic leukemia cells - TIB-202; ATCC) transcriptional responses of; (i) uninfected versus Coxiella burnetii NMII infected and (ii) uninfected versus Coxiella burnetii NMII infected THP-1 cells transiently treated with bacteriostatic levels (10μg/ml) of chloramphenicol (CAM). Briefly, infections were initiated and cultured in parallel with uninfected cells. At 48 hours post infection (hpi), media containing CAM (10μg/ml) was added to one set of cells (uninfected and infected THP-1 cells) and culturing was continued. The other set of cells were mock treated with normal media. Total RNA was isolated at 72 hpi from all conditions. Microarrays were performed for both condition sets and the results from each of the two microarrays were compared to define the host genes modulated by de novo C. burnetii NMII protein synthesis.
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.
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
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.