Search results for "Clostridium"
showing 10 items of 128 documents
Sequencing and analysis of the gene encoding the α-toxin of Clostridium novyi proves its homology to toxins A and B of Clostridium difficile
1995
A library of total Clostridium novyi DNA was established and screened for the alpha-toxin gene (tcn alpha) by hybridization with oligonucleotides derived from a partial N-terminal sequence and by using specific antisera. Overlapping subgenic tcn alpha fragments were isolated and subsequently the total sequence of tcn alpha was determined. The 6534 nucleotide open reading frame encodes a polypeptide of M(r) 250,166 and pI 5.9. The N-terminal alpha-toxin (Tcn alpha) sequence MLITREQLMKIASIP determined by Edman degradation confirmed the identity of the reading frame and the assignment of the translation start point. The toxin is not modified posttranslationally at its N-terminus nor does it co…
Clostridium baratii bacteremia associated with Kawasaki syndrome. First case report
2007
We experienced a case of a 3-year-old boy who presented signs and symptoms of Kawasaki syndrome. Two blood culture sets were processed by the hospital microbiology laboratory using a standard blood culturing system. The anaerobic bottles gave a positive result at day 3 after inoculation. The biochemical profiles produced by the RapID ANA II System showed that the organism was Clostridium baratii with a probability of 99%. Our case highlights the importance of C. baratii as a potential human pathogen and reports the associations with manifestations, which, to our knowledge, have not been previously described concomitantly with a clostridial infection.
Large clostridial cytotoxins — a family of glycosyltransferases modifying small GTP-binding proteins
1996
Some Clostridium species produce AB x -type protein cytotoxins of high molecular weight. These toxins constitute the group of large clostridial cytotoxins (LCTs), which have homologous protein sequences, exert glycosyltransferase activity and modify GTP-binding proteins of the Ras-superfamily. These characteristics render the LCTs valuable tools for developmental and cell biologists.
Metabolism of polychlorinated norbornenes by Clostridium butyricum.
1972
STUDIES of the metabolism of cyclodien-insecticides, such as dieldrin, endrin, endosulphan, have revealed valuable information about their fate in the ecosystem1. With all metabolites identified so far, however, the hexachlorinated norbornene moiety remains unchanged2,3. Only from photodieldrin, a cage-like derivative of dieldrin, have dechlorinated metabolites been reported4,5.
Midgut microbiota and host immunocompetence underlie Bacillus thuringiensis killing mechanism
2016
Bacillus thuringiensis is a widely used bacterial entomopathogen producing insecticidal toxins, some of which are expressed in insect-resistant transgenic crops. Surprisingly, the killing mechanism of B. thuringiensis remains controversial. In particular, the importance of the septicemia induced by the host midgut microbiota is still debated as a result of the lack of experimental evidence obtained without drastic manipulation of the midgut and its content. Here this key issue is addressed by RNAi-mediated silencing of an immune gene in a lepidopteran host Spodoptera littoralis, leaving the midgut microbiota unaltered. The resulting cellular immunosuppression was characterized by a reduced …
Hydrolysis and microbial community analyses in two-stage anaerobic digestion of energy crops
2007
Aims: The roles of the diverse populations of micro-organisms responsible for biodegradation of organic matter to form methane and carbon dioxide are rudimentarily understood. To expand the knowledge on links between microbial communities and the rate limiting, hydrolytic stage of two-stage biogas production from energy crops, this study was performed. Methods and Results: The process performance. and microbial communities (as determined by fluorescence in situ hybridization) in two separate two-stage batch digestions of sugar beets and grass/clover were studied. The microbial populations developed in the hydrolytic stage of anaerobic digestion of beets and grass/clover showed very few simi…
Transcription analysis of the genes tcdA-E of the pathogenicity locus of Clostridium difficile.
1997
To analyse the transcription pattern of the five tcdA-E genes of the pathogenicity locus (PaLoc) of Clostridium difficile a protocol was established to purify RNA from strain VPI10463. Transcription analysis of the five tcdA-E genes showed that they were all transcribed. In the early exponential phase, a high level of tcdC and low levels of tcdA,B,D,E transcripts were detectable; this was inverted in the stationary phase, suggesting that TcdC might have a negative influence on transcription of the other genes. Three transcription initiation sites, one for tcdA and two for tcdB were determined by primer extension analysis. Readthrough transcripts from outside the locus were not obtainable, s…
EVALUATION OF STABILITY AND ENZYMATIC ACTIVITIES OF PROTEOLYTIC ENZYMES USED IN PANCREATIC ISLET TRANSPLANTATION
2009
In pancreatic islets purification, for cell therapy applications, the major enzymes used are obtained from Clostridium hystoliticum; class I and class II collagenases (Coll-G and Coll-H). In a well defined composition Coll-G/Coll-H together enzymes working on hydrophobic amminoacid, the neutral protease (Dispase) or the thermolysin (Thermostable Neutral Protease), are used in Langerhans islets purification. By electrophoresis and gelatin zymography approaches, in combination to densitometry quantitative valuation we have compared in composition, stability and autodigestion processes C. hystoliticum collagenases, Neutral protease and Thermolysin from two different producers, Roche and Serva.…
Clostridium difficile heterogeneously impacts intestinal community architecture but drives stable metabolome responses
2015
Clostridium difficile-associated diarrhoea (CDAD) is caused by C. difficile toxins A and B and represents a serious emerging health problem. Yet, its progression and functional consequences are unclear. We hypothesised that C. difficile can drive major measurable metabolic changes in the gut microbiota and that a relationship with the production or absence of toxins may be established. We tested this hypothesis by performing metabolic profiling on the gut microbiota of patients with C. difficile that produced (n=6) or did not produce (n=4) toxins and on non-colonised control patients (n=6), all of whom were experiencing diarrhoea. We report a statistically significant separation (P-value o0…
Characterization of the cleavage site and function of resulting cleavage fragments after limited proteolysis of Clostridium difficile toxin B (TcdB) …
2005
Clostridium difficiletoxin B (TcdB) is a single-stranded protein consisting of a C-terminal domain responsible for binding to the host cell membrane, a middle part involved in internalization, and the N-terminal catalytic (toxic) part. This study shows that TcdB is processed by a single proteolytic step which cleaves TcdB10463between Leu543and Gly544and the naturally occurring variant TcdB8864between Leu544and Gly545. The cleavage occurs at neutral pH and is catalysed by a pepstatin-sensitive protease localized in the cytoplasm and on the cytoplasmic face of intracellular membranes. The smaller N-terminal cleavage products [63 121 Da (TcdB10463) and 62 761 Da (TcdB8864)] harbour the cytotox…