<i>Photorhabdus asymbiotica</i>
            , a Pathogen Emerging on Two Continents That Proves that There Is No Substitute for a Well-Trained Clinical Microbiologist

Weissfeld, Alice S.; Halliday, Rhonda J.; Simmons, Dawn E.; Trevino, Ernest; Vance, Paula H.; O'Hara, C M; Sowers, Evangeline G.; Kern, R. R.; Koy, R. Dudley; Hodde, Kathy; Bing, Mo; Lo, Carson K L; Gerrard, John; Vohra, Renu; Harper, Jacqueline

doi:10.1128/jcm.43.8.4152-4155.2005

Cited by 34 publications

(23 citation statements)

References 5 publications

(2 reference statements)

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“…Only one species, Photorhabdus asymbiotica, has both a MazF homologue (http://www.sanger.ac.uk /Projects/P_asymbiotica/) and an unprotected ACA in its tmRNA. Although this bacterium is classified as being a member of the Enterobacteriaceae, its biochemical characteristics are quite different from those of most other enterobacteria (46). Its distinct physiology might require a different response to stress than MazF-induced growth regulation.…”

Section: Correlation Of Mazf Homologues and The Absence Of Acas In Tmmentioning

confidence: 99%

Significant Bias against the ACA Triplet in the tmRNA Sequence of Escherichia coli K-12

et al. 2009

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The toxin MazF in Escherichia coli cleaves single-stranded RNAs specifically at ACA sequences. MazF overexpression virtually eliminates all cellular mRNAs to completely block protein synthesis. However, protein synthesis can continue on an mRNA that is devoid of ACA triplets. The finding that ribosomal RNAs remain intact in the face of complete translation arrest suggested a purpose for such preservation. We therefore examined the sequences of all transcribed RNAs to determine if there was any statistically significant bias against ACA. While ACA motifs are absent from tmRNA, 4.5S RNA, and seven of the eight 5S rRNAs, statistical analysis revealed that only for tmRNA was the absence nonrandom. The introduction of single-strand ACAs makes tmRNA highly susceptible to MazF cleavage. Furthermore, analysis of tmRNA sequences from 442 bacteria showed that the discrimination against ACA in tmRNAs was seen mostly in enterobacteria. We propose that the unusual bias against ACA in tmRNA may have coevolved with the acquisition of MazF.

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Section: Correlation Of Mazf Homologues and The Absence Of Acas In Tmmentioning

confidence: 99%

Significant Bias against the ACA Triplet in the tmRNA Sequence of Escherichia coli K-12

et al. 2009

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“…The nematode parasite Heterorhabditis gerrardi contains the mutualistic bacteria P. asymbiotica that are able to infect both insects and humans (Plichta et al, 2009; Weissfeld et al, 2005). Photorhabdus bacteria produce a wide range of toxins, virulence factors andhydrolytic enzymes (Bode, 2009; Costa et al, 2010; ffrench-Constant et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

TGF-β signaling regulates resistance to parasitic nematode infection in Drosophila melanogaster

2016

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Over the past decade important advances have been made in the field of innate immunity; however, our appreciation of the signaling pathways and molecules that participate in host immune responses to parasitic nematode infections lags behind that of responses to microbial challenges. Here we have examined the regulation and immune activity of Transforming Growth Factor-beta (TGF-β) signaling in the model host Drosophila melanogaster upon infection with the nematode parasites Heterorhabditis gerrardi and H. bacteriophora containing their mutualistic bacteria Photorhabdus. We have found that the genes encoding the Activin and Bone Morphogenic Protein (BMP) ligands Dawdle (Daw) and Decapentaplegic (Dpp) are transcriptionally induced in flies responding to infection with the nematode parasites, containing or lacking their associated bacteria. We also show that deficient Daw or Dpp regulates the survival of D. melanogaster adults to the pathogens, whereas inactivation of Daw reduces the persistence of the nematodes in the mutant flies. These findings demonstrate a novel role for the TGF-β signaling pathways in the host anti-nematode immune response. Understanding the molecular mechanisms of host anti-nematode processes will potentially lead to the development of novel means for the efficient control of parasitic nematodes.

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“…To date, 14 cases have been documented, including 6 in the United States and 8 in Australia. The infections caused by P. asymbiotica are characterized by local infection of soft tissue, with the formation of subcutaneous nodules (12,18,23,32). P. asymbiotica seems to be mainly a primary pathogen rather than an opportunistic one and was qualified in Australia as an emergent pathogen.…”

mentioning

confidence: 99%

The Emerging Human Pathogen Photorhabdus asymbiotica Is a Facultative Intracellular Bacterium and Induces Apoptosis of Macrophage-Like Cells

et al. 2009

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Photorhabdus species are gram-negative entomopathogenic bacteria of the family Enterobacteriaceae. Among the different members of the genus, one species, Photorhabdus asymbiotica, is a pathogen of both insects and humans. The pathogenicity mechanisms of this bacterium are unknown. Here we show that P. asymbiotica is a facultative intracellular pathogen that is able to replicate inside human macrophage-like cells. Furthermore, P. asymbiotica was shown for the first time in an intracellular location after insect infection. We also demonstrated that among Australian and American clinical isolates, only the Australian strains were able to invade nonphagocytic human cells. In cell culture infection experiments, Australian clinical isolates as well as cell-free bacterial culture supernatant induced strong apoptosis of a macrophage cell line at 6 h postinfection. American isolates also induced cellular death, but much later than that induced by Australian ones. Mammalian cultured cells analyzed for key features of apoptosis displayed apoptotic nuclear morphology, activation of the initiator caspases 8 and 9 and the executioner caspases 3 and 7, and poly(ADP-ribose) polymerase proteolysis, suggesting activation of both the intrinsic and extrinsic apoptotic pathways.

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Photorhabdus asymbiotica , a Pathogen Emerging on Two Continents That Proves that There Is No Substitute for a Well-Trained Clinical Microbiologist

Cited by 34 publications

References 5 publications

Significant Bias against the ACA Triplet in the tmRNA Sequence of Escherichia coli K-12

Significant Bias against the ACA Triplet in the tmRNA Sequence of Escherichia coli K-12

TGF-β signaling regulates resistance to parasitic nematode infection in Drosophila melanogaster

The Emerging Human Pathogen Photorhabdus asymbiotica Is a Facultative Intracellular Bacterium and Induces Apoptosis of Macrophage-Like Cells

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