Project description:Actinobacillus pleuropneumoniae is the etiological agent of porcine pleuropneumonia, a respiratory disease which causes great economic losses worldwide. Many virulence factors are involved in the pathogenesis, namely capsular polysaccharides, RTX toxins, LPS and many iron acquisition systems. In order to identify genes that are expressed in vivo during a natural infection, we undertook transcript profiling experiments with an A. pleuropneumoniae DNA microarray, after recovery of bacterial mRNAs from serotype 5b-infected porcine lungs. Comparative Genomic Hybridizations between Actinobacillus pleuropneumoniae serotype 5b strain L20 (ref) and serotype 5b fresh field isolate 896-07, recovered from infected pig lung tissues following natural acute infection. Two condition transcript profiling experiments : infectious 5b field strain isolated directly from lungs of naturally deceased pigs after acute infection vs infectious 5b field strain grown in BHI broth to an OD600 of 0.300.
Project description:Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, is a highly contagious respiratory pathogen that causes severe losses to the swine industry worldwide. Current commercially-available vaccines are of limited value because they do not induce cross-serovar immunity and do not prevent development of the carrier state. Microarray-based comparative genomic hybridizations (M-CGH) were used to estimate whole genomic diversity of representative Actinobacillus pleuropneumoniae strains. Our goal was to identify conserved genes, especially those predicted to encode outer membrane proteins and lipoproteins because of their potential for the development of more effective vaccines. Using hierarchical clustering, our M-CGH results showed that the majority of the genes in the genome of the serovar 5 A. pleuropneumoniae L20 strain were conserved in the reference strains of all 15 serovars and in representative field isolates. Fifty-eight conserved genes predicted to encode for outer membrane proteins or lipoproteins were identified. As well, there were several clusters of diverged or absent genes including those associated with capsule biosynthesis, toxin production as well as genes typically associated with mobile elements. Keywords: Comparative Genomic Hybridization
Project description:Microarray-based comparative genomic hybridizations were used to estimate whole genomic diversity of representative Actinobacillus pleuropneumoniae strains. Our goal was to identify conserved genes, especially those predicted to encode outer membrane proteins and lipoproteins because of their potential for the development of more effective vaccines. Keywords: Comparative Genomic Hybridisation
Project description:Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, is a highly contagious respiratory pathogen that causes severe losses to the swine industry worldwide. Current commercially-available vaccines are of limited value because they do not induce cross-serovar immunity and do not prevent development of the carrier state. Microarray-based comparative genomic hybridizations (M-CGH) were used to estimate whole genomic diversity of representative Actinobacillus pleuropneumoniae strains. Our goal was to identify conserved genes, especially those predicted to encode outer membrane proteins and lipoproteins because of their potential for the development of more effective vaccines. Using hierarchical clustering, our M-CGH results showed that the majority of the genes in the genome of the serovar 5 A. pleuropneumoniae L20 strain were conserved in the reference strains of all 15 serovars and in representative field isolates. Fifty-eight conserved genes predicted to encode for outer membrane proteins or lipoproteins were identified. As well, there were several clusters of diverged or absent genes including those associated with capsule biosynthesis, toxin production as well as genes typically associated with mobile elements. Keywords: Comparative Genomic Hybridization Two condition CGH experiments : tested strains vs reference 5bL20 strain. 26 strains were tested, with 2-4 technical replicates per strain, for a total of 74 samples. One replicate per array.
Project description:Microarray-based comparative genomic hybridizations were used to estimate whole genomic diversity of representative Actinobacillus pleuropneumoniae strains. Our goal was to identify conserved genes, especially those predicted to encode outer membrane proteins and lipoproteins because of their potential for the development of more effective vaccines. Keywords: Comparative Genomic Hybridisation Microarray data for 15 known serotypes of Actinobacillus pleuropneumoniae (at least 2 replicates per serotype).
Project description:Actinobacillus pleuropneumoniae is the etiologic agent of contagious pleuropneumonia, an economically important disease of commercially reared swine throughout the world. To cause this disease, A. pleuropneumoniae must rapidly overcome porcine pulmonary innate immune defenses. Effects of koromycin, an antimicrobial agent that acts as an noncompetitive inhibitor of the interaction of NQR with its quinone substrate, on the transcriptome of A. pleuropneumoniae was investigated.
Project description:LuxS is an enzyme involved in the activated methyl cycle and the by-product autoinducer 2 (AI-2) was a quorum sensing signal in some species. In our previous study, the functional LuxS in AI-2 production was verified in the porcine respiratory pathogen Actinobacillus pleuropneumoniae. Enhanced biofilm formation and reduced virulence were observed in the luxS mutant. To comprehensively understand the luxS function, in this study, the transcriptional profiles were compared between the A. pleuropneumoniae luxS mutant and its parental strain in four different growth phases using microarray. Many genes associated with infection were differentially expressed. The biofilm formation genes pgaABC in the luxS mutant were up-regulated in early exponential phase, while 8 genes associated with adhesion were down-regulated in late exponential phase. A group of genes involved in iron acquisition and metabolism were regulated in four growth phases. Further investigations on these virulence traits demonstrated that the luxS mutant showed enhanced biofilm formation and reduced adhesion ability and these effects were not due to lack of AI-2. But AI-2 could increase biofilm formation and adhesion of A. pleuropneumoniae independent of LuxS. Growth under iron restricted condition could be controlled by LuxS through AI-2 production. These results revealed pleiotropic roles of LuxS and AI-2 on A. pleuropneumoniae virulence traits. A. pleuropneumoniae strains were cultured in TSB medium supplemented with 10 M-NM-<g/ml of nicotinamide adenine dinucleotide (NAD) and 10% (v/v)filtered cattle serum at 37M-BM-0C. The samples were collected from early exponential phase, middle exponential phase, late exponential phase and stationary phase respectively and the total RNA were extracted using RNA-Solv Reagent (Omega) according to the manufacturerM-bM-^@M-^Ys instructions. For each time point, four biological replicates were combined into two samples. The intensities were normalized and transformed into log2 value.The fold changes >=1.5 or <=-1.5 were selected as differentially expressed genes.
Project description:To make clear the genetic diversity and virulence evolution at the genome-wide level of A. pleuropneumoniae Keywords: comparative genomic hybridization