Characterization of a Unique ADP-Ribosyltransferase of
            <i>Mycoplasma penetrans</i>

Johnson, Coreen; Kannan, Thirumalai R; Baseman, Joel B.

doi:10.1128/iai.00044-09

Cited by 10 publications

(10 citation statements)

References 37 publications

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“…For example, Johnson et al recently showed the region 2 STS motif is not strictly needed in an M. penetrans ADPRT [55]. Also, the PARP10 ADPRT does not need the hallmark “catalytic Glu” because it uses a substrate-assisted mechanism [77].…”

Section: Resultsmentioning

confidence: 99%

“…Future toxin discoveries will involve not only new entries to public sequence and structure databases, but also updates to the search pattern and perhaps even new folds. For example, Johnson et al recently showed the region 2 STS motif is not strictly needed in an M. penetrans ADPRT [55] . Also, the PARP10 ADPRT does not need the hallmark “catalytic Glu” because it uses a substrate-assisted mechanism [77] .…”

Section: Resultsmentioning

confidence: 99%

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Cholera- and Anthrax-Like Toxins Are among Several New ADP-Ribosyltransferases

et al. 2010

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Chelt, a cholera-like toxin from Vibrio cholerae, and Certhrax, an anthrax-like toxin from Bacillus cereus, are among six new bacterial protein toxins we identified and characterized using in silico and cell-based techniques. We also uncovered medically relevant toxins from Mycobacterium avium and Enterococcus faecalis. We found agriculturally relevant toxins in Photorhabdus luminescens and Vibrio splendidus. These toxins belong to the ADP-ribosyltransferase family that has conserved structure despite low sequence identity. Therefore, our search for new toxins combined fold recognition with rules for filtering sequences – including a primary sequence pattern – to reduce reliance on sequence identity and identify toxins using structure. We used computers to build models and analyzed each new toxin to understand features including: structure, secretion, cell entry, activation, NAD+ substrate binding, intracellular target binding and the reaction mechanism. We confirmed activity using a yeast growth test. In this era where an expanding protein structure library complements abundant protein sequence data – and we need high-throughput validation – our approach provides insight into the newest toxin ADP-ribosyltransferases.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Cholera- and Anthrax-Like Toxins Are among Several New ADP-Ribosyltransferases

et al. 2010

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“…These conditions would not allow for outgrowth of subpopulations, as the generation time of M. gallisepticum is approximately 2 h. More recently, a two-component signal transduction system was putatively identified in the M. penetrans genome (16), and seven previously unidentified transcription factors have been characterized empirically in M. pneumoniae (38), which contributes more evidence that mycoplasmas can sense and respond to the milieu in which they reside. In this study, genomic comparisons of strains R low and F were undertaken at the functional level, utilizing microarrays described in a previous transcriptomic study.…”

Section: Discussionmentioning

confidence: 98%

Identification of Lipoprotein MslA as a Neoteric Virulence Factor of Mycoplasma gallisepticum

et al. 2010

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Many lipoproteins are expressed on the surfaces of mycoplasmas, and some have been implicated as playing roles in pathogenesis. Family 2 lipoproteins of Mycoplasma pneumoniae have a conserved "mycoplasma lipoprotein X" central domain and a "mycoplasma lipoprotein 10" C-terminal domain and are differentially expressed in response to environmental conditions. Homologues of family 2 lipoproteins are Mycoplasma specific and include the lipoprotein of Mycoplasma gallisepticum, encoded by the MGA0674 gene. Comparative transcriptomic analysis of the M. gallisepticum live attenuated vaccine strain F and the virulent strain R low , reported in this study, indicated that MGA0674 is one of several differentially expressed genes. The MGA0674-encoded lipoprotein is a proteolytically processed, immunogenic, TX-114 detergent-phase protein which appears to have antigenic divergence between field strains R low and S6. We examined the virulence of an R low ⌬MGA0674 mutant (P1H9) in vivo and observed reduced recovery and attenuated virulence in the tracheas of experimentally infected chickens. The virulence of two additional R low ⌬MGA0674 mutants, 2162 and 2204, was assessed in a second in vivo virulence experiment. These mutants exhibited partial to complete attenuation in vivo, but recovery was observed more frequently. Since only Mycoplasma species harbor homologues of MGA0674, the gene product has been renamed "Mycoplasma-specific lipoprotein A" (MslA). Collectively, these data indicate that MslA is an immunogenic lipoprotein exhibiting reduced expression in an attenuated strain and plays a role in M. gallisepticum virulence.Mycoplasma gallisepticum is a respiratory and reproductive tract pathogen of poultry, and disease results in major economic losses on commercial farms. M. gallisepticum can be transmitted via inhalation of aerosolized respiratory secretions and can also be spread vertically to the offspring of infected hens. Attachment of the bacterium to host respiratory epithelium results in inflammation, metaplasia, and loss of cilia. M. gallisepticum infection also places infected chickens at increased risk of developing a more severe, and potentially fatal, polymicrobial disease known as chronic respiratory disease (CRD) (18). Several live attenuated vaccines (LAV) have been generated to manage M. gallisepticum disease on chicken farms, but little is known about the genetic basis for their attenuation. We recently undertook an investigation of the genetic means by which the LAV strain F became avirulent by sequencing its complete genome and comparing it with the genome of the virulent strain R low . Deletions and mutations in many genes were identified as significantly altering the coding sequence and may have an effect on virulence. We showed that a transposon knockout of the "hypothetical" gene MGA1107 in R low (gene deleted in strain F) resulted in attenuation of the organism in vivo, indicating that this gene plays a role in the pathogenesis of M. gallisepticum (33).Lipoproteins (LPs) reside on the surfaces of th...

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“…Our finding that M. iowae has an ability to prolong survival when fed to C. elegans larvae following growth in 1% O 2 supports the notion that M. iowae is not harmful in the gut and might in fact be a beneficial component of the gut microflora. Significantly, at the transcriptional level, this environment causes a significant down-regulation in not only the gene encoding catalase, but also a gene encoding a homolog of CARDS toxin, a causative agent of host damage by M. pneumoniae [ 20 , 55 ] and M. penetrans [ 56 ]. These data suggest that M. iowae undergoes differential regulation of select genes in response to growth in low O 2 environments.…”

Section: Discussionmentioning

confidence: 99%

Mycoplasma iowae: relationships among oxygen, virulence, and protection from oxidative stress

Pritchard

Balish

2015

Vet Res

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The poultry-associated bacterium Mycoplasma iowae colonizes multiple sites in embryos, with disease or death resulting. Although M. iowae accumulates in the intestinal tract, it does not cause disease at that site, but rather only in tissues that are exposed to atmospheric O2. The activity of M. iowae catalase, encoded by katE, is capable of rapid removal of damaging H2O2 from solution, and katE confers a substantial reduction in the amount of H2O2 produced by Mycoplasma gallisepticum katE transformants in the presence of glycerol. As catalase-producing bacteria are often beneficial to hosts with inflammatory bowel disease, we explored whether M. iowae was exclusively protective against H2O2-producing bacteria in a Caenorhabditis elegans model, whether its protectiveness changed in response to O2 levels, and whether expression of genes involved in H2O2 metabolism and virulence changed in response to O2 levels. We observed that M. iowae was in fact protective against H2O2-producing Streptococcus pneumoniae, but not HCN-producing Pseudomonas aeruginosa, and that M. iowae cells grown in 1% O2 promoted survival of C. elegans to a greater extent than M. iowae cells grown in atmospheric O2. Transcript levels of an M. iowae gene encoding a homolog of Mycoplasma pneumoniae CARDS toxin were 5-fold lower in cells grown in low O2. These data suggest that reduced O2, representing the intestinal environment, triggers M. iowae to reduce its virulence capabilities, effecting a change from a pathogenic mode to a potentially beneficial one.

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Characterization of a Unique ADP-Ribosyltransferase of Mycoplasma penetrans

Cited by 10 publications

References 37 publications

Cholera- and Anthrax-Like Toxins Are among Several New ADP-Ribosyltransferases

Cholera- and Anthrax-Like Toxins Are among Several New ADP-Ribosyltransferases

Identification of Lipoprotein MslA as a Neoteric Virulence Factor of Mycoplasma gallisepticum

Mycoplasma iowae: relationships among oxygen, virulence, and protection from oxidative stress

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