Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Expression data of Actinobacillus pleuropneumoniae 4074 and the M-NM-^TluxS mutant of Actinobacillus pleuropneumoniae 4074

ABSTRACT: 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-=1.5 or <=-1.5 were selected as differentially expressed genes.

ORGANISM(S): Actinobacillus pleuropneumoniae

SUBMITTER: Zhuofei Xu

PROVIDER: E-GEOD-19056 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Analysis on Actinobacillus pleuropneumoniae LuxS regulated genes reveals pleiotropic roles of LuxS/AI-2 on biofilm formation, adhesion ability and iron metabolism.

Li Lu L Xu Zhuofei Z Zhou Yang Y Li Tingting T Sun Lili L Chen Huanchun H Zhou Rui R

Microbial pathogenesis 20110212 6

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. pleuropne ...[more]

PMID: 21320583

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Project description:LuxS is an enzyme involved in the activated methyl cycle. The by-product of this cycle, autoinducer 2 (AI-2), could be an important quorum sensing signal. LuxS was conserved and regulated many behaviors in different bacteria, but in most species, whether the regulations are related to AI-2 mediated quorum sensing is still unknown. In our previous study, Actinobacillus pleuropneumoniae, the etiologic agent of porcine contagious pleuropneumonia, was found to possess the functional LuxS affecting biofilm formation and virulence. In this study, microarray was used to compare the transcriptional profiles of the A. pleuropneumoniae wildtype strain 4074, luxS mutant and its AI-2 supplemented strain in four different growth phases. The results demonstrated that both LuxS and AI-2 played important roles in metabolism of this bacterium. AI-2 did not recover the gene expression changes caused by luxS deletion but caused more extensive metabolic alterations in the luxS mutant in a concentration dependent manner. Regulations of the genes involved in iron metabolism, carbonhydrate transport and host cell adhesion were validated by real-time RT-PCR and phenotypic investigations under different conditions. The results demonstrated that sugar uptake was repressed by LuxS independent of AI-2. However, iron metabolism, an important process of infection for A. pleuropneumoniae, could be controlled by LuxS through AI-2. Adhesion to host cells was also affected by LuxS and AI-2, but exogenous AI-2 displayed more obvious effects. Our results indicated that both LuxS and AI-2 are essential in the metabolism of A. pleuropneumoniae. The function of LuxS/AI-2 displayed pleiotropic roles in different conditions. AI-2 may not serve as a quorum sensing autoinducer but a metabolite or an environmental cue to affect the metabolism and virulence traits of this important pathogen. 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. For samples from the mutant supplemented with AI-2, 100M-NM-<M and 25M-NM-<M AI-2 precursor (DPD) were added into the medium before early exponential phase as well as one hour before late exponential phase to cover the whole growth phase respectively. The samples were collected from early, middle, 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 values for each time point were averaged and the genes with log2 ratio >=1 or <=-1 were selected as differentially expressed genes.

Project description:Actinobacillus pleuropneumoniae is an important porcine respiratory pathogen causing great economic losses in the pig industry worldwide. Oxygen deprivation is a stress that A. pleuropneumoniae will encounter during both early infection and the later, persistent stage. To understand modulation of A. pleuropneumoniae gene expression in response to the stress caused by anaerobic conditions, gene expression profiles under anaerobic and aerobic conditions were compared in this study. The microarray results showed that 631 genes (27.7% of the total ORFs) were differentially expressed in anaerobic conditions. Many genes encoding proteins involved in glycolysis, carbon source uptake systems, pyruvate metabolism, fermentation and the electron respiration transport chain were up-regulated. These changes led to an increased amount of pyruvate, lactate, ethanol and acetate in the bacterial cells as confirmed by metabolite detection. Genes encoding proteins involved in cell surface structures, especially biofilm formation, peptidoglycan biosynthesis and lipopolysaccharide biosynthesis were up-regulated as well. Biofilm formation was significantly enhanced under anaerobic conditions. These results indicate that induction of central metabolism is important for basic survival of A. pleuropneumoniae after a shift to an anaerobic environment. Enhanced biofilm formation may contribute to the persistence of this pathogen in the damaged anaerobic host tissue and also in the early colonization stage. These discoveries give new insights into adaptation mechanisms of A. pleuropneumoniae in response to environmental stress. Transcriptional profiles were analyzed using microarray to compare the gene expressions of A. pleuropneumoniae cultured under aerobic and anaerobic condition. The bacteria was cultured under aerobic condition to mid-log phase (3 hours) and then divided into two separate groups, one group was continually cultured under aerobic condition for 1 hour (OD600nm = 0.417 M-BM-1 0.008) and the other group was cultured under anaerobic condition for 1 hour (OD600nm = 0.333 M-BM-1 0.015). Three independent biological replicates were performed. The total RNA were extracted and hybridized with the whole genome microarray of A. pleuropneumoniae. The signal intensities were normalized and transformed into log2 values. The genes with P-value < 0.05 were selected as differentially expressed genes.

Project description:Bacteria can use host hormones as environment cue to modulate their pathogenic processes, which was discovered to play essential role in disease development. Actinobacillus pleuropneumoniae is one of the most important porcine respiratory pathogens causing great economic losses in the pig industry worldwide. Stress factors were found to contribute to the outcome of A. pleuropneumoniae infection. To test whether A. pleuropneumoniae could respond to host stress hormone catecholamines, the gene expression profiles after epinephrine (Epi) and norepinephrine (NE) treatment were compared with the untreated bacteria using microarray. Although the bacterial growth was not affected in the conditions tested, 157 and 104 genes associated with various function categories including many virulence factors were differentially expressed by Epi and NE treatment. 18 common genes were regulated by the two hormones, these genes included genes encoding virulence factors and potential responsors of Epi and NE. Further investigations on virulence traits demonstrated that cytotoxic activity was enhanced by Epi but repressed by NE in accordance with the regulations on apxIA. Biofilm formation was not affected by the two hormones despite that the biofilm formation gene pgaB was affected. Adhesion to host cells was induced by NE but not by Epi, possibly involving other putative adhesins affected by the hormones in addition to the autotransporter adhesin (APL_0443). Our study demonstrated that A. pleuropneumoniae could actively respond to catecholamines to control its virulence traits. The different regulated genes and effects caused by Epi and NE suggested A. pleuropneumoniae may have multiple responsive systems to sense different type of catecholamine hormones. Transcriptional profiles were analyzed using microarray to compared the epinephrine (Epi) or norepinephrine(NE) treated and untreated A. pleuropneumoniae. All samples were harvested from middle exponential phase (4 hours after sub-culture) at the OD600=1.435M-BM-10.065 for control, OD600=1.461M-BM-10.019 for Epi treated strain and OD600=1.545M-BM-10.115 for NE treated strain. Three biological replicates were conducted for each treatment. The total RNA were extracted and hybridized with the whole genome microarray of A. pleuropneumoniae. The signal intensities were normalized and transformed into log2 values. The genes with fold change M-bM-^IM-% 1.5 and P < 0.05 were selected as differentially expressed.

Dataset Information

Expression data of Actinobacillus pleuropneumoniae 4074 and the M-NM-^TluxS mutant of Actinobacillus pleuropneumoniae 4074

Publications

Analysis on Actinobacillus pleuropneumoniae LuxS regulated genes reveals pleiotropic roles of LuxS/AI-2 on biofilm formation, adhesion ability and iron metabolism.

Similar Datasets

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