Project description:Objectives: To determine the transcripts that are differentially expressed in a hfq mutant. Hfq is an RNA chaperone that mediates many interactions between regultory RNAs and their mRNA targets. Analysis of the transcriptomes of the Pasteurella multocida wild-type strain and the Pasteurella multocida hfq mutant will allow for identification of genes controlled by hfq and the sRNAs with which it interacts.
Project description:Objectives: To determine the transcripts that are differentially expressed in a hfq mutant. Hfq is an RNA chaperone that mediates many interactions between regultory RNAs and their mRNA targets. Analysis of the transcriptomes of the Pasteurella multocida wild-type strain and the Pasteurella multocida hfq mutant will allow for identification of genes controlled by hfq and the sRNAs with which it interacts. Methods: RNA sequencing was employed to determine the transcriptomes of a wild-type Pasteurella multocida strain and a hfq mutant strain. Comparison of these two transcriptomes allows for determination of differentially expressed genes and therefore those genes controlled by Hfq and sRNAs with which it interacts.
Project description:In this study, transcriptomic analysis of the P. multocida strain VP161 revealed a putative sRNA with high identity to GcvB from Escherichia coli and Salmonella enterica serovar Typhimurium. High-throughput quantitative liquid proteomics was used to compare the proteomes of the P. multocida VP161 wild-type strain, a gcvB mutant and a GcvB overexpression strain. These analyses identified 47 proteins that displayed significant differential production after inactivation of gcvB, 37 of which showed increased production. Thus, GcvB predominantly acts to negatively regulate protein production in P. multocida. Of the 37 proteins that were repressed by GcvB, 27 were predicted to be involved in amino acid biosynthesis or transport. Bioinformatic analyses of putative P. multocida GcvB target mRNAs identified a strongly conserved 10 nucleotide consensus sequence, 5’‑AACACAACAT-3’, with the central eight nucleotides identical to the seed binding region present within GcvB mRNA targets in E. coli and S. Typhimurium.
Project description:Pasteurella multocida is a Gram-negative capsulated bacterium responsible for a range of diseases that cause severe morbidity and mortality in livestock animals. The hyaluronic acid (HA) capsule produced by P. multocida serogroup A strains is a critical virulence factor. In this study, we utilised transposon-directed insertion site sequencing (TraDIS) to identify genes essential for in vitro growth of P. multocida, and combined TraDIS with discontinuous density gradients (TraDISort) to identify genes required for HA capsule production and regulation in this pathogen. Analysis of mutants with a high cell density phenotype, indicative of the loss of extracellular capsule, led to the identification of 69 genes important for capsule production. These genes included all previously characterized genes in the capsule biosynthesis locus, and fis and hfq that encode known positive regulators of P. multocida capsule. Many of the other capsule-associated genes identified in this study were involved in regulation or activation of the stringent response, including spoT and relA that encode proteins that regulate the concentration of guanosine alarmones. Disruption of the autoregulatory domains in the C-terminal half of SpoT using insertional mutagenesis resulted in reduced expression of capsule biosynthesis genes and an acapsular phenotype. Overall, these findings have greatly increased the understanding of hyaluronic acid capsule production and regulation in P. multocida.
Project description:We studied the effects of three classes of antibiotics (amoxicillin, chlortetracycline and enrofloxacin ) on P. multocida transcriptome using custom oligonucleotide microarrays from Nimblegen systems. All the 2015 genes of Pm70 were spotted on the array and hybridizations were carried out with RNA isolated from three independent cultures of Pm70 grown in the presence or absence of sub-minimum inhibitory (sub-MIC) doses of antibiotics. Differentially expressed genes were identified by ANOVA and Dunnett’s test. Biological modeling of the differentially expressed genes (DE) was carried out based on Clusters of Orthologous (COG) groups and network analysis in Pathway Studio. Keywords: Response to sub-MIC antibiotics The experimental design included three biological replicate cultures of P. multocida grown in the absence or presence of sub-MIC antibiotics. Effects of antibiotics on the transcriptome with each antibiotic were determined by comparing the growth in the presence of antibiotic (treatment) to growth in the absence of antibiotic (control).
