Project description:Mycoplasma hyopneumoniae, the causative agent of swine enzootic pneumonia, colonizes the cilia of swine lungs, causing ciliostasis and cell death. Mycoplasma hyopneumoniae is a component of the porcine respiratory disease complex (PRDC) and is especially problematic for the finishing swine industry, causing the loss of hundreds of millions of dollars in farm revenues worldwide. For successful infection, M. hyopneumoniae must effectively resist oxidative stresses due to the release of oxidative compounds from neutrophils and macrophages during the host’s immune response. However, the mechanism M. hyopneumoniae uses to avert the host response is still unclear. To gain a better understanding of the transcriptional responses of M. hyopneumoniae under oxidative stress, cultures were grown to early exponential phase and exposed to 0.5% percent hydrogen peroxide for 15 minutes. RNA samples from these cultures were collected and compared to RNA samples from control cultures using two-color PCR-based M. hyopneumoniae microarrays. This study revealed significant down-regulation of important glycolytic pathway genes and gene transcription proteins, as well as a protein known to activate oxidative stressor cascades in neutrophils. This study has also contained significantly differentially expressed genes common to other environmental stress responses, and merits further study of universal stress response genes of M. hyopneumoniae. Keywords: Mycoplasma hyopneumoniae, RNA microarray
Project description:The experiment consists of M.hyp 232 cultures digests analyzed on two mass specs, LTQ Velos Pro and LTQ FT Ultra LTQ Velos Pro: Six cell culture replicates of M.hyo 232 were hydrophobically separated using tree detergents: Digitonin, Tween, and SDS. Each francion, including the insoluble pellet, was trypsin digested and then cleaned using an SCX trap follwed by a RP trap to remove detergents. Each fraction was sepated using a Dionex U3000 splitless nanoflow system operating at 333 nl per minute using a gradient of 2% ACN to 50% ACN in 4 hours. Eluate was analyzed using an LTQ Velos Pro mass spectrometer with 20 MS/MS scans of the 20 most intense peaks from each MS scan. Dynamic exclusion was enable for 3 minutes for each m/z with a repeat count of 1. LTQ FT Ultra: Two cell pellets for high resolution analysis were lysed and trypsin digested. Digested peptides were dried, resuspended in 20 mM KH2PO4, 20% ACN, pH 3 (Buffer A) in 2.5 µL and transferred to low retention vials in preparation for separation using an Ultimate 3000 configured for 2D-LC. Each sample was loaded at 15 µl/min onto an SCX microtrap for the first dimension of separation, involving SCX steps of Buffer A + 0, 5, 10, 15, 20, 25, 30, 40, 50, 100, 250, 500, and 1000 mM KCl. For the second dimension of separation, each eluted salt step was desalted with an inline peptide microtrap with 2% ACN, 0.1% FA at 5 µl/min. Once desalted, the microtrap was switched into line with a fritless nano column (75µm x ~10cm) containing C18 media (5µ, 200 Å Magic, Michrom). Peptides were eluted using a gradient of 2% to 36% ACN, 0.1% FA at 350 nl/min over 60 min and electrospray ionized for analysis using an LTQ FT Ultra mass spectrometer. A survey scan m/z 350-1750 was acquired in the FT ICR cell (Resolution = 100,000 at m/z 400, with an accumulation target value of 1,000,000 ions). Up to the 6 most abundant ions (>3,000 counts) with charge states > +2 were sequentially isolated and fragmented within the linear ion trap using collisionally induced dissociation with an activation q = 0.25 and activation time of 30 ms at a target value of 30,000 ions. M/z ratios selected for MS/ MS were dynamically excluded for 30 seconds. Analysis: X!tandem searches were performed using the Mycoplasma hyopneumoniae strain 232 reference protein set from NCBI. The only difference between the searches for the LTQ Velos and LTQ FT was the precursor mass tolenance being set to +-1500ppm and +-24ppm respectively. Decoy searches were performed and the data filtered at e-value <= 0.01 with single peptide proteins discarded. These results are included in the submission as two tab-delimited text files.
Project description:Mycoplasma hyopneumoniae causes swine pneumonia and contributes significantly to porcine respiratory disease complex. The mechanisms of pathogenesis are difficult to address since there is a lack of genetic tools, but microarrays can be used to study transcriptional changes that occur during colonization and disease in pigs. This approach has the potential to identify genes important to virulence. This study sought to identify genes that change transcript levels during infection. To accomplish this, organisms collected from bronchial alveolar lavages were compared to that of broth grown organisms. Bronchial alveolar lavage was performed on pigs 28 days post infection with M. hyopneumoniae, and organisms were isolated by differential centrifugation. Mycoplasma RNA enriched preparations were then obtained from total RNA by subtracting eucaryotic ribosomal and messenger RNAs. cDNA was generated with mycoplasma ORF-specific primers, fluorescently labeled with Cy3 and Cy5, and used to interrogate microarrays. Arrays were scanned and analyzed using a mixed linear statistical model. Nine biological replicates were analyzed in this fashion. Our analysis indicated that 33 Mhyo genes were up-regulated and 46 genes were down-regulated (p<0.01) during disease in the pig lung at a false discovery rate < 2.7%. Of the down-regulated genes, 27 of 46 (59%) lacked assigned function, and 20 of 33 (61%) of the up-regulated genes were hypothetical genes. Four down-regulated and two up-regulated genes were putative lipoproteins. secA (mhp295; p = 0.003), and two glycerol transport permeases (potA (mhp380); p = 0.006 and ugpA (mhp381); p = 0.003) were up-regulated in vivo. Elongation factor EF-G (fusA (mhp083); p = 0.002), rpoC (mhp635; p = 0.003), adenylate kinase (adk (mhp208); p = 0.001), prolyl aminoacyl tRNA synthetase (proS (mhp397); p = 0.009) and cysteinyl-tRNA synthetase (cysS (mhp661); p < 0.001) were down-regulated in vivo. Keywords: RNA, spotted DNA/cDNA
Project description:Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia and a major factor in the porcine respiratory disease complex. A clear understanding of the mechanisms of pathogenesis does not exist although it is clear that M. hyopneumoniae adheres to porcine ciliated epithelium by action of a protein called P97. Previous studies have shown variation in the gene encoding the P97cilium adhesin within different strains of M. hyopneumoniae, but the extent of genetic variation among field strains across the genome is not known. Since M. hyopneumoniae is a worldwide problem, it is reasonable to expect that a wide range of genetic variability may exist given all of the different breed and housing conditions. This variation may impact the overall virulence of a single strain. Using microarray technology, this study examined potential variation of fourteen field strains in comparison to strain 232 on which the array was based. Genomic DNA was obtained, amplified with TempliPhi™, and labeled indirectly with Alexa dyes. Post genomic hybridization, the arrays were scanned and data analyzed using a linear statistical model. Results indicate that genetic variation could be detected in all fourteen field strains but across different loci, suggesting that variation occurs throughout the genome. Fifty-nine percent of the variable loci were hypothetical genes. Twenty-two percent of the lipoprotein genes showed variation in at least one field strain. A permutation test identified a location in M. hyopneumoniae genome where spatial clustering of variability between the field strains and strain 232 exists. Keywords: CGH, Mycoplasma Hyopneumoniae