Molecular basis for the pathological actions of Clostridium perfringens iota toxin.

Clostridium perfringens type E iota toxin is composed of two separate and independent polypeptide chains that act synergistically in mouse lethal assays. The light chain is an enzyme that mono(ADP-ribosyl)ates certain amino acids. The enzyme displays substantial activity when homopoly-L-arginine is used as a substrate, but it shows little activity when polyasparagine, polylysine or polyglutamic acid are used.

Purification and characterization of Clostridium perfringens iota toxin: dependence on two nonlinked proteins for biological activity.

Clostridium perfringens type E iota toxin, a dermonecrotic and lethal binary toxin, was purified to homogeneity. Each protein component of the toxin, iota a (ia) or iota b (ib), appeared as a single band by gradient or sodium dodecyl sulfate-polyacrylamide gel electrophoresis and yielded a single immunoprecipitin arc by crossed immunoelectrophoresis with homologous antiserum. Individually, ia (Mr 47,500) or ib (Mr 71,500) had little biological activity.

Stimulation of enzyme secretion from isolated pancreatic acini by Clostridium difficile toxin B.

Exposure of isolated rat pancreatic acini to increasing concentrations (10 ng - 800 ng/ml) of toxin B from Clostridium difficile produced a biphasic effect on the rate of secretion of amylase, trypsinogen, and chymotrypsinogen. Whereas doses of toxin B from 10-30 ng/ml increased enzyme secretion by 15-20%, doses between 30 ng and 60 ng/ml showed a regression of this effect, whereafter the rate of secretion of amylase, trypsinogen, and chymotrypsinogen increased with increasing concentrations of the toxin. Toxin B concentration of 800 ng/ml enhanced amylase, trypsinogen and chymotrypsinogen secretion by 119%, 185% and 195%, respectively, when compared with the basal level.

Characterization of toxins A and B of Clostridium difficile with monoclonal antibodies.

Two monoclonal antibodies (MAbs) were used to learn more about the structures of Clostridium difficile toxins A and B. One of the antibodies, the PCG-4 MAb, reacted specifically with toxin A. This MAb precipitated toxin A and neutralized the enterotoxic but not the cytotoxic activity of the toxin.

Cell surface binding site for Clostridium difficile enterotoxin: evidence for a glycoconjugate containing the sequence Gal alpha 1-3Gal beta 1-4GlcNAc.

This study was undertaken to determine whether a binding site for Clostridium difficile enterotoxin (toxin A) exists in the brush border membranes (BBMs) of the hamster, an animal known to be extremely sensitive to the action of the toxin. Toxin A was the only antigen adsorbed by the BBMs from the culture filtrate of C. difficile.

Significance of Clostridium spiroforme in the enteritis-complex of commercial rabbits.

Commercial rabbits showing clinical signs of enteritis-complex were examined for the presence of Clostridium spiroforme and its iota-like toxin. The bacterium was detected by Gram stain in 52.4% of 149 cecal samples and iota-like toxin in 7.

Comparison of culture, cytotoxicity assays, and enzyme-linked immunosorbent assay for toxin A and toxin B in the diagnosis of Clostridium difficile-related enteric disease.

Clostridium difficile culture, test tube, and microtiter cytotoxicity assays, and enzyme-linked immunosorbent assays (ELISAs) for toxin A and toxin B, were simultaneously performed on 113 fresh diarrheal stool specimens randomly selected from those submitted to our clinical laboratory for routine C. difficile testing. The performance of these tests in diagnosing C.

Commercial latex test for Clostridium difficile toxin A does not detect toxin A.

The rapid latex test recently marketed by Marion Scientific (Div. Marion Laboratories, Inc., Kansas City, Mo.

Assay performance and tracer properties for two analog-based assays of free triiodothyronine.

We determined binding characteristics of the triiodothyronine (T3) analog tracer used in the Amerlex and Amerlex-M FT3 radioimmunoassay for the three endogenous binding proteins in serum: thyroxin-binding globulin (TBG), thyroxin binding prealbumin (PA), and albumin. Both T3 and its analog bind to the same sites on TBG and PA. However, the analog has significantly lower association constants (1.

Clostridium perfringens iota toxin: synergism between two proteins.

The iota toxin of Clostridium perfringens type E is a guinea pig dermonecrotic, mouse lethal toxin which cross-reacts with the iota-like toxin of Clostridium spiroforme. Antiserum raised against C. spiroforme or C.

Comprehensive study of a thyroxin-analog-based assay for free thyroxin ("Amerlex FT4").

The basic theory of thyroxin-analog-based radioimmunoassays for free thyroxin has been extended to evaluate definitively the effects arising from residual binding of the tracer analog to serum proteins. Using experimentally determined binding constants and computer simulation techniques, we studied the effects of thyroxin-analog binding to serum proteins on results of Amerlex FT4 radioimmunoassay, using this improved mathematical model. Results from computer-simulation studies were compared both directly with in vitro experimental results and indirectly with clinical studies.

Comparative in-vitro activity of Sch 34343 for a wide spectrum of clinically significant anaerobic bacteria.

One hundred and fifty strains of anaerobic bacteria including 45 bacteroides, 19 fusobacteria, 41 cocci, 34 clostridia, and 11 Gram-positive non-sporeforming rods were tested by agar dilution for their susceptibilities to cefoxitin, cefuroxime, latamoxef (moxalactam), penicillin G, chloramphenicol, clindamycin, metronidazole and Sch 34343. Excluding the 34 clostridia, 115 of the 116 remaining strains were inhibited by less than or equal to 1 mg/l of Sch 34343. One isolate of Bacteroides fragilis required 32 mg/l for inhibition.

Effects of Clostridium difficile toxins given intragastrically to animals.

We examined the activities of Clostridium difficile toxin preparations given intragastrically to hamsters, mice, and rats. The culture filtrate from a highly toxigenic strain of C. difficile caused hemorrhage and accumulation of fluid in the small intestine and cecum, diarrhea, and death in hamsters and mice.

Monoclonal and specific polyclonal antibodies for immunoassay of Clostridium difficile toxin A.

Monoclonal antibody, affinity-purified antibody, and monospecific antiserum against toxin A were produced. The monoclonal antibody was an immunoglobulin G2a kappa chain isotype that immunoprecipitated toxin A, as shown by crossed immunoelectrophoresis. These antibodies were compared by counterimmunoelectrophoresis, latex agglutination, and indirect enzyme-linked immunosorbent assay for their sensitivity in detecting toxin A.

Clostridial toxins active locally in the gastrointestinal tract.

Clostridium difficile and Clostridium spiroforme have only in recent years been recognized as intestinal pathogens. They both produce toxins that are also produced by other clostridia. C.

In vitro and in vivo neutralizing activity of human colostrum and milk against purified toxins A and B of Clostridium difficile.

The neutralizing activity (NA) of supernates of colostral samples collected postpartum from 55 women and tested against a 50% cytopathic dose of purified toxins A and B of Clostridium difficile was evaluated in Y1 adrenal cells. Thirty-one (56%) of the samples had NA against one or both toxins. Samples of breast milk were collected postpartum from five women-three had colostral NA and two did not.

On distribution of different fecapentaenes, the fecal mutagens, in the human population.

It has been shown by an HPLC analysis using a quarternary solvent mixture in an isocratic mode that human excretors of these fecal mutagens excrete both fecapentaene -12 and -14 but the ratios vary greatly between individuals. Since these mutagens are produced by the bacterial flora of the colon, this may indicate differences in the flora between these individuals or differences in the availability of different precursor molecules in their colons. Any relationship of these findings to the etiology of colonic cancer is not clear.