Transcription profiling of 3 Bordetella bronchiseptica strains plus or minus nicotinic acid
ABSTRACT: Three B. bronchiseptica strains were grown at 37 degrees C in media containing or lacking nicotinic acid. Samples were harvested at mid-log phase and gene expression difference between the treated and untreated was measured for each strain.
The Bordetella master virulence regulatory system, BvgAS, controls a spectrum of gene expression states, including the virulent Bvg(+) phase, the avirulent Bvg(-) phase, and at least one Bvg-intermediate (Bvg(i)) phase. We set out to define the species- and strain-specific features of this regulon based on global gene expression profiling. Rather than functioning as a switch, Bvg controls a remarkable continuum of gene expression states, with hundreds of genes maximally expressed in intermediate ...[more]
Project description:B. pertussis GMT-1 was grown in media containing magnesium sulfate to put the culture in the Bvg- phase. The cells were then washed and grown in media lacking magnesium sulfate and samples were harvested at time=0 and several time points beyond.
Project description:Two strains of B. pertussis were serially passaged on plates in the laboratory. Global gene expression profiles were measured for passage 1 and late-passage cultures grown in Bvg+ and Bvg- environmental conditions.
Project description:bvgS phase-locked mutant derivatives of B. bronchiseptica RB50, B. pertussis GMT-1, and B. pertussis Tohama I were grown at 37 degrees C in the absence of modulator and harvested at mid-log phase. Comparison of gene expression profiles identified a set of genes in each strain that were regulated by BvgAS.
Project description:Campylobacter jejuni is a widespread pathogen responsible for most of the food-borne gastrointestinal diseases in Europe. For pathogen control in the food industry, the use of natural antimicrobial molecules is a promising strategy to avoid antibiotic treatments. Isothiocyanates are natural antimicrobial compounds which also display anti-cancer activity. Several studies described the chemoprotective effect of isothiocyanates on eukaryotic cells, but the antimicrobial mechanism is still poorly understood. We investigated the early cellular response of C. jejuni to benzylisothiocyanate (BITC) by both transcriptomic and physiological (respirometry, ATP content measurements and isolations of aggregated proteins). To characterize the transcriptomic early response to benzylisothiocyanate, C. jejuni NCTC11168 were grown in 100 ml flasks containing 25 ml of MEMα medium plus 20 mM sodium pyruvate. At mid-log phase, 2µg/mL benzylisothiocyanate in ethanol, or the same volume of ethanol (control) was added to the flasks for 10 or 15 min prior to total RNA extraction and purification. Samples were then processed for microarray hybridization. Microarray data was acquired from two (10 minutes assay) or three (15 minutes assay) independent biological replicates and 6 to 9 technical replicates for each biological replicate (total number of measurement per gene = 42).
Project description:Transcriptional regulation mediates adaptation of pathogens to environmental stimuli and is important for host colonisation. The Campylobacter jejuni genome sequence reveals a surprisingly small set of regulators, mostly of unknown function, suggesting an intricate regulatory network. Interestingly, C. jejuni lacks the homologues of ubiquitous regulators involved in stress response found in many other Gram-negative bacteria. Nonetheless, cj1000 is predicted to code for the sole LysR-type regulator in the C. jejuni genome, and thus may be involved in major adaptation pathways. A cj1000 mutant strain was constructed and found to be attenuated in its ability to colonise 1-day old chicks. Complementation of cj1000 mutation restored the colonisation ability to that of wild type levels. The mutant strain was also outcompeted in a competitive colonisation assay of the piglet intestine. High resolution oxygraphy was carried out for the first time on C. jejuni and revealed a role for Cj1000 in controlling O2 consumption. Furthermore, microarray analysis of the cj1000 mutant revealed both direct and indirect regulatory targets, including genes involved in energy metabolism and oxidative stress defences. These results highlight the importance of Cj1000 regulation in host colonisation and in major physiological pathways. Microarray data was collected from three independent biological replicates and 3-9 technical replicates for each biological replicate.
Project description:The zur regulon in Neisseria meningitidis was elucidated in the strain MC58 using a zur knockout strain and conditions which activate Zur ( zinc supplementation in the medium) Common reference design, zur knock out strain was used as the common reference and the samples wild type strain grown in RPMI and in RPMI with Zinc supplementation were compared to the common reference.