Search results for "Clostridium Difficile"

Delineation of the catalytic domain of Clostridium difficile toxin B-10463 to an enzymatically active N-terminal 467 amino acid fragment.

2006

Abstract In an attempt to directly approach the postulated toxic domain of Clostridium difficile 's TcdB-10463, eight subclones of different size and locations in the N-terminal third of the toxin were generated. Expression of these toxin fragments was checked in Western blots and the enzymatic activity of the expressed proteins was analyzed by glucosylating Ras related small GTP-binding proteins. Two polypeptides of 875 aa (TcdBc1–3) and 557 aa (TcdBc1-H) glucosylated their targets Rho, Rac and Cdc42 with the same activity and specificity as the holotoxin. In comparison 516 aa (TcdBc1-N) and 467 aa (TcdBc1-A) protein fragments exhibited highly reduced activity, while Tcdc1 and TcdB2–3 (aa …

Evidence for a modular structure of the homologous repetitive C-terminal carbohydrate-binding sites of Clostridium difficile toxins and Streptococcus…

1992

The homologous C-terminal repeats of Clostridium difficile toxins (ToxA and ToxB) and streptococcal glucosyltransferases appear to mediate protein-carbohydrate interactions at cellular binding sites with sugar moieties as substrates. A consensus sequence of 134 repeating units from gram-positive bacteria indicates that these repeats have a modular design with (i) a stretch of aromatic amino acids proposed to be involved in the primary carbohydrate-protein interaction, (ii) an amplification of this interaction by repetition of the respective sequences, and (iii) a second domain, not characterized, that is responsible for carbohydrate specificity.

Structural and functional changes in the gut microbiota associated to Clostridium difficile infection

2014

Antibiotic therapy is a causative agent of severe disturbances in microbial communities. In healthy individuals, the gut microbiota prevents infection by harmful microorganisms through direct inhibition (releasing antimicrobial compounds), competition, or stimulation of the host’s immune defenses. However, widespread antibiotic use has resulted in short- and long-term shifts in the gut microbiota structure, leading to a loss in colonization resistance in some cases. Consequently, some patients develop Clostridium difficile infection (CDI) after taking an antibiotic (AB) and, at present, this opportunistic pathogen is one of the main causes of antibiotic-associated diarrhea in hospitalized p…

Autocatalytic cleavage of Clostridium difficile toxin B.

2007

Clostridium difficile, the causative agent of nosocomial antibiotic-associated diarrhoea and pseudomembranous colitis, possesses two main virulence factors: the large clostridial cytotoxins A and B. It has been proposed that toxin B is cleaved by a cytosolic factor of the eukaryotic target cell during its cellular uptake. Here we report that cleavage of not only toxin B, but also all other large clostridial cytotoxins, is an autocatalytic process dependent on host cytosolic inositolphosphate cofactors. A covalent inhibitor of aspartate proteases, 1,2-epoxy-3-(p-nitrophenoxy)propane, completely blocked toxin B function on cultured cells and was used to identify its catalytically active prote…

Identification of acetyl-T-2 toxin, a trichothecene, in moldy rice by HPLC and FDMS

1982

Digestive disorders and Intestinal microbiota

2018

In the last decade, a barge body of scientific literature has suggested that specific alterations of the gut microbiota may be associated with ther development and clinical course of several gastrointestinal diseases, including irritable bowel syndrome, inflammatory bowel disease, celiac disease, gastrointestinal cancer and Clostridium difficile infection. These alterations are often referred to as “dysbiosis”, a generic term designing reduction of gut microbiota biodiversity and alterations in its composition. Here, we provide a synthetic overview of the key concepts on the relationship between intestinal microbiota and gastrointestinal diseases, focusing on the translation of these concep…

Clostridium difficile infekcijas gadījumu analīze stacionārā Latvijas Infektoloģijas Centrs

2016

Clostridium difficile slimību (CDI) skaits pēdējos gados dramatiski pieaug. Vienu no svarīgākajiem šīs problēmas aspektiem var atrisināt, ja tiks kvalitatīvi un kvantitatīvi izvērtēti iespējamie riska faktori, kas predisponē Clostridium difficile slimības attīstību. Pētījuma mērķis bija atrast nozares, kur tiek pārmērīgi izmantotas plaša spektra antibiotikas, kas veicina slimības incidences pieaugumu, kā arī novērtēt laboratorisko rādītāju izmaiņas atkarībā no slimības smaguma pakāpes. Retrospektīvā pētījuma laikā, tika analizētas 60 Latvijas Infektoloģijas centrā stacionētu pacientu medicīniskās kartes 2014.-2015. g. periodā, kuriem tika apstiprināta diagnoze – Clostridium difficile infekc…

Nucleotide sequence of Clostridium difficile toxin A.

1990

Cloning and Characterization of Overlapping DNA Fragments of the Toxin A Gene of Clostridium difficile

1989

Clostridium difficile, a human pathogen, produces two very large protein toxins, A and B (250-600 kDa), which resist dissociation into subunits. To clone the toxin A gene, a genomic library of 3-8 kb chromosomal DNA fragments of C. difficile strain VPI 10463 established in pUC12 was screened with a rabbit polyclonal toxin A antiserum. Thirty-five clones were isolated which carried 2.5-7.0 kb inserts representing a 10 kb region of the C. difficile genome. All the inserts were oriented in the same direction, suggesting that toxin A gene expression was under control of the lac promoter of the pUC12 vector. Western blot experiments revealed the presence of low amounts of fusion proteins of vari…

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…