A5074691887- Clostridium difficile and Clostridium perfringens research
- Bacterial Genetics and Biotechnology
- Streptococcal Infections and Treatments
- Antimicrobial Resistance in Staphylococcus
- Toxin Mechanisms and Immunotoxins
- Botulinum Toxin and Related Neurological Disorders
- Bacterial biofilms and quorum sensing
- Viral gastroenteritis research and epidemiology
- Bacterial Identification and Susceptibility Testing
- Chemical Synthesis and Analysis
- Microbial Inactivation Methods
- Dermatological and COVID-19 studies
- Biochemical and Structural Characterization
- Vibrio bacteria research studies
- Gut microbiota and health
- Vitamin C and Antioxidants Research
- Genomics and Phylogenetic Studies
- Microbial Community Ecology and Physiology
- Insect and Pesticide Research
- Helicobacter pylori-related gastroenterology studies
- Cancer therapeutics and mechanisms
- Monoclonal and Polyclonal Antibodies Research
- Microbial infections and disease research
- Amino Acid Enzymes and Metabolism
- Bacteriophages and microbial interactions
Monash University
2004-2020
Australian Regenerative Medicine Institute
2006-2020
Australian Research Council
2011-2013
Australian Centre for HIV and Hepatitis Virology Research
2006
Northern Arizona University
1997
Clostridium perfringens is a Gram-positive, anaerobic spore-forming bacterium commonly found in soil, sediments, and the human gastrointestinal tract. C. responsible for wide spectrum of disease, including food poisoning, gas gangrene (clostridial myonecrosis), enteritis necroticans, non-foodborne infections. The complete genome sequences strain ATCC 13124, isolate species type strain, enterotoxin-producing poisoning SM101, were determined compared with published 13 genome. Comparison three...
Summary Clostridium difficile is an emerging nosocomial pathogen of increasing importance and virulence but our ability to study the molecular mechanisms underlying pathogenesis C. ‐associated disease has been limited because a lack tools for its genetic manipulation. We have now developed reproducible method targeted insertional inactivation chromosomal genes. The approach relies on observation that Escherichia coli–Clostridium perfringens shuttle vector unstable in can be used as form...
The pathogenesis of avian necrotic enteritis involves NetB, a pore-forming toxin produced by virulent isolates Clostridium perfringens type A. To determine the location and mobility netB structural gene, we examined derivative tetracycline-resistant strain EHE-NE18, in which was insertionally inactivated chloramphenicol thiamphenicol resistance gene catP. Both tetracycline could be transferred either together or separately to recipient plate matings. separate transconjugants act as donors...
ABSTRACT Clostridium perfringens is an anaerobic bacterium that causes numerous important human and animal diseases, primarily as a result of its ability to produce many different protein toxins. In chickens, C. necrotic enteritis, disease economic importance the worldwide poultry industry. The secreted pore-forming toxin NetB key virulence factor in pathogenesis avian enteritis similar alpha-hemolysin, β-barrel from Staphylococcus aureus . To address molecular mechanisms underlying...
Clostridium perfringens causes several diseases in domestic livestock, including necrotic enteritis chickens, which is of concern to the poultry industry due its health implications and associated economic cost. The novel pore-forming toxin NetB a critical virulence factor pathogenesis this disease. In study, we have examined regulation production. C. perfringens, quorum sensing-dependent VirSR two-component signal transduction system regulates genes encoding toxins extracellular enzymes....
Clostridium difficile is a global health burden and the leading cause of antibiotic-associated diarrhoea worldwide, causing severe gastrointestinal disease death. Three well characterised toxins are encoded by this bacterium in two genetic loci, specifically, TcdB (toxin B) TcdA A) Pathogenicity Locus (PaLoc) binary toxin (CDT) genomically distinct CDT locus (CdtLoc). Toxin production controlled regulators specific to each locus. The orphan response regulator, CdtR, within CdtLoc,...
The first gene to encode a haloarchaeal bacteriocin (halocin H4) has been cloned and sequenced from Haloferax mediterranei R4. Both the signal sequence in halocin H4 preprotein monocistronic halH4 have some unusual features. physiology of expression reveals that although transcripts are present at low basal levels during exponential growth, activity appears as culture enters stationary phase. As increase, so do transcript levels, but then decrease precipitously while remain elevated.
ABSTRACT Regulation of toxin production in the gram-positive anaerobe Clostridium perfringens occurs at level transcription and involves a two-component signal transduction system. The sensor histidine kinase is encoded by virS gene, while its cognate response regulator virR gene. We have constructed VirR expression plasmid Escherichia coli purified resultant His-tagged protein. Gel mobility shift assays demonstrated that binds to region upstream pfoA which encodes perfringolysin O, but not...
Toxin production in Clostridium perfringens is controlled by the VirSR two-component signal transduction system, which comprises VirS sensor histidine kinase and VirR response regulator. Other studies have concentrated on elucidation of genes this network; there little information regarding phosphorelay cascade that hallmark such regulatory systems. In study, we examined each step cascade, beginning with autophosphorylation VirS, followed phosphotransfer from to VirR. We also studied effects...
ABSTRACT Clostridium perfringens causes clostridial myonecrosis or gas gangrene and produces several extracellular hydrolytic enzymes toxins, many of which are regulated by the VirSR signal transduction system. The revR gene encodes a putative orphan response regulator that has similarity to YycF (WalR), VicR, PhoB, PhoP proteins from other Gram-positive bacteria. RevR appears be classical regulator, with an N-terminal receiver domain C-terminal winged helix-turn-helix DNA binding region. To...
ABSTRACT To obtain an insight into host-pathogen interactions in clostridial myonecrosis, we carried out comparative transcriptome analysis of both the bacterium and host a murine Clostridium perfringens infection model, which is first time that such investigation has been conducted. Analysis from infected muscle tissues indicated many genes were upregulated compared to results seen with mock-infected mice. These enriched for defense pathways, including Toll-like receptor (TLR) Nod-like...
Clostridium septicum is the causative agent of atraumatic gas gangrene, with α-toxin, an extracellular pore-forming toxin, essential for disease. How C. modulates host’s innate immune response poorly defined, although α-toxin-intoxicated muscle cells undergo cellular oncosis, characterised by mitochondrial dysfunction and release reactive oxygen species. Nonetheless, signalling events that occur prior to initiation oncosis are characterised. Our aims were characterise ability α-toxin...
The transcriptional regulation of toxin production in the gram-positive anaerobe Clostridium perfringens involves a two-component signal transduction system that comprises VirS sensor histidine kinase and its cognate response regulator, VirR. Previous studies showed VirR binds independently to pair imperfect direct repeats, now designated box 1 2, located immediately upstream promoter pfoA gene, which encodes cholesterol-dependent cytolysin, perfringolysin O. For this study, we introduced...
Among many other virulence factors, Clostridium perfringens produces three sialidases NanH, NanI and NanJ. NanH lacks a secretion signal peptide is predicted to be an intracellular enzyme, while NanJ are secreted. Previously, we had identified part of operon encoding NanE (epimerase) NanA (sialic acid lyase) enzymes. Further analysis the entire suggests that it encodes complete pathway for transport metabolism sialic along with putative transcriptional regulator, NanR. The addition 30 mM...
Clostridium perfringens is ubiquitous in nature and often found as a commensal of the human animal gastrointestinal tract. It primary etiological agent clostridial myonecrosis, or gas gangrene, serious infection that results extensive tissue necrosis due to action one more potent extracellular toxins. α-toxin perfringolysin O are major toxins involved pathogenesis but histotoxic strains C. perfringens, such strain 13, also produce many degradative enzymes collagenases, hyaluronidases,...
ABSTRACT The vrl locus is preferentially associated with virulent isolates of the ovine footrot pathogen, Dichelobacter nodosus . complete nucleotide sequence this 27.1-kb region has now been determined. data reveal that a G+C content much higher than rest D. chromosome and contains 22 open reading frames (ORFs) encoding products including putative adenine-specific methylase, two potential DEAH ATP-dependent helicases, similarity to bacteriophage resistance system. These ORFs are all in same...
Clostridium perfringens is the causative agent of clostridial myonecrosis or gas gangrene and produces many different extracellular toxins enzymes, including cysteine protease α-clostripain. Mutation α-clostripain structural gene, ccp, alters turnover secreted proteins in C. perfringens, but role disease pathogenesis not known. We insertionally inactivated ccp gene strain 13 using TargeTron technology, constructing a that was no longer proteolytic on skim milk agar. Quantitative assays...
Clostridium perfringens causes toxin-mediated diseases, including gas gangrene (clostridial myonecrosis) and food poisoning in humans. The production of the toxins implicated gangrene, α-toxin perfringolysin O, is regulated by VirSR two-component regulatory system. In addition, RevR, an orphan response regulator, has been shown to affect virulence mouse myonecrosis model. RevR positively regulates expression genes that encode hydrolytic enzymes, hyaluronidases sialidases. To further...
TnpX is a site-specific recombinase responsible for the excision and insertion of transposons Tn4451 Tn4453 in Clostridium perfringens difficile, respectively. Here, we exploit phenotypic features to facilitate genetic mutagenesis complementation studies. Genetic manipulation bacteria often relies on use antibiotic resistance genes; however, limited number are available clostridia. The ability recognize excise specific DNA fragments was exploited here as basis an marker recycling system,...