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T Miwatani

Publications and source records attributed to T Miwatani.

At least 127 records · Page 7Linked to original sources
PubMed1984

A virulence plasmid in Escherichia coli enterotoxigenic for humans: intergenetic transfer and expression.

We studied the colonization-factor antigen I (CFA/I) fimbriae- and heat-stable enterotoxin (ST)-coding plasmid of enterotoxigenic Escherichia coli (strain H10407, serotype O78:H11) pathogenic for humans. With use of conjugal-transfer system of E. coli H10407 and transposon-labeling techniques, the virulence plasmid was shown to be transferable to many species of the family Enterobacteriaceae, including the enteropathogens, Shigella and Salmonella species, and the opportunistic pathogens, Klebsiella, Enterobacter, Citrobacter, Edwardsiella, Serratia, and Proteus species. The virulence plasmid-carrying transconjugants produced both CFA/I fimbriae and ST (exotoxin). Moreover, most of the transconjugants stably inherited the virulence plasmid, although plasmid stability was greatly dependent on culture temperature. Finally, administration of the virulence plasmid-carrying living bacterial cells of Klebsiella, Enterobacter, and Citrobacter species and E. coli K12 resulted in fluid accumulation in both infant-mouse and rabbit ileal-loop tests.

Animals↗
PubMed1984

Characterization of new hydrophobic pili of human enterotoxigenic Escherichia coli: a possible new colonization factor.

Enterotoxigenic Escherichia coli strains were divided into five groups on the basis of their bacterial surface hydrophobicity (Honda et al., FEMS Microbiol. Lett. 17:273-276, 1983). Strains in group III showed heat-stable high hydrophobicity, although they did not show mannose-resistant hemagglutination with either human or bovine erythrocytes. E. coli strain 260-1 in group III was characterized. Electron microscopic examination revealed the presence of pili on the surface of this strain, but not on that of strain 260-1a, which is a mutant of 260-1 showing low hydrophobicity. When strain 260-1 was grown at 18 degrees C, it did not produce pili or show high hydrophobicity. On homogenization of strain 260-1 grown at 37 degrees C the high hydrophobicity and the pili on its surface were lost. These results indicate that the pili of strain 260-1 are associated with the hydrophobicity. Strain 260-1 pili were purified to homogeneity by successive column chromatographies on Sepharose 4B and phenyl-Sepharose CL-4B. Their molecular weight was estimated to be about 18,000. An antigenic difference between purified pili of strain 260-1 and colonization factor antigens I and II was demonstrated. The colonization ability of E. coli 260-1 was shown by animal experiments on suckling mice and infant rabbits. From these results it is concluded that the pili of strains in group III of human enterotoxigenic E. coli, which may play a role in colonization, are of a new type.

Animals↗
PubMed1984

Non-O1 Vibrio cholerae hemolysin: purification, partial characterization, and immunological relatedness to El Tor hemolysin.

Hemolysin of a non-O1 Vibrio cholerae strain was purified and characterized. The purified hemolysin gave a single protein band on conventional and sodium dodecyl sulfate-gel electrophoresis. Its molecular weight was estimated as 60,000 by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. It had a pI of 5.7. The purified hemolysin caused increased vascular permeability of rabbit skin and rapid death of mice on intravenous injection and also lysed erythrocytes of various animal species. An Ouchterlony double gel diffusion test using antiserum against the purified hemolysin indicated that the hemolysin from non-O1 V. cholerae was immunologically related, but not identical, to the hemolysin from El Tor V. cholerae. Antiserum against the purified hemolysin neutralized the hemolytic activity of the hemolysins from not only non-O1 but also El Tor V. cholerae.

Animals↗
PubMed1984

Comparison of effects of nicked and unnicked Escherichia coli heat-labile enterotoxin on Chinese hamster ovary cells.

The effect on nicking (proteolytic cleavage) of heat-labile enterotoxin (LT) on its activities on Chinese hamster ovary (CHO) cells was examined. LT nicked with trypsin induced morphological change (elongation) of CHO cells from round to spindle-shaped cells faster than did unnicked LT. The times for elongation of 50% of the CHO cells with nicked and unnicked LT were 3 and 6 h, respectively. The activity of nicked LT on CHO cells was not inhibited by antiserum 20 min after treatment, whereas that of unnicked LT was inhibited by antiserum until ca. 130 to 160 min after treatment. These data suggest that unnicked LT remains on the cell surface longer than nicked LT and thus induces morphological changes of CHO cells more slowly than does nicked LT.

Animals↗
PubMed1984

Differential detection of cholera enterotoxin and Escherichia coli heat-labile enterotoxin by enzyme-linked immunosorbent assays with antibodies specific to the two toxins.

Enzyme-linked immunosorbent assays (ELISAs) with antibodies specific to either cholera enterotoxin (CT) of Vibrio cholerae or heat-labile enterotoxin (LT) of enterotoxigenic Escherichia coli were developed to detect LT and CT, respectively. With these ELISA systems, LT and CT could be detected only with the respective specific antibody. Both antibody ELISA and ganglioside ELISA were used for differential detection of LT and CT, but the former method seemed to be more specific. By this ELISA, as little as 0.1 ng of purified LT or CT could be detected per ml. The type of toxins in fluids in intestinal loops of experimental animals challenged with living cells of either V. cholerae or LT-producing E. coli was identified correctly by this ELISA. These results suggest that the ELISA systems reported here could be used to detect and differentiate CT and LT in unknown samples; it could also be used for assaying toxins in stool specimens for the diagnosis of diarrhea due to V. cholerae or LT-producing E. coli directly, without or before bacterial isolation.

Animals↗
PubMed1983

Chemical synthesis of a highly potent and heat-stable analog of an enterotoxin produced by a human strain of enterotoxigenic Escherichia coli.

A shorter analog of a heat-stable enterotoxin produced by a human strain of enterotoxigenic Escherichia coli SK-1, consisting of 14 amino acid residues including 6 half-cystine residues, was synthesized by conventional methods. The peptide was evaluated for ability to induce intestinal secretion in suckling mice and for stability at high temperature under various conditions. The peptide was 2-5 times more potent than native toxin and was still toxic after heat-treatment at 120 degrees C for 30 min.

Amino Acid Sequence↗
PubMed1983

Amino acid sequence of a heat-stable enterotoxin isolated from enterotoxigenic Escherichia coli strain 18D.

A heat-stable enterotoxin produced by a strain of enterotoxigenic Escherichia coli 18D was purified by ion-exchange and reversed-phase high-pressure liquid chromatography. The amino acid sequence of the purified toxin was determined by Edman-degradation and a combination of fast atom bombardment mass spectrometry and carboxypeptidase digestion to be Asn-Thr-Phe-Tyr-Cys-Cys-Glu-Leu-Cys-Cys-Asn-Pro-Ala-Cys-Ala-Gly-Cys-Tyr.

Amino Acid Sequence↗
PubMed1983

Purification and some properties of a non-o1 Vibrio cholerae enterotoxin that is identical to cholera enterotoxin.

Cholera-like enterotoxin was isolated and purified from the culture supernatant of a non-O1 strain of Vibrio cholerae, E8498, isolated from the environment. Enterotoxin was purified by aluminum hydroxide absorption and elution and successive gel filtrations on Sephadex G-100, Bio-Gel A-5m, and Sephadex G-75. Purified enterotoxin gave a single stained band on polyacrylamide gel disc electrophoresis, and the mobility was the same as that of cholera enterotoxin. The specific biological activity of the purified enterotoxin was almost the same as that of cholera enterotoxin in the Chinese hamster ovary cell assay, fluid accumulation in mouse ligated intestine, increase in vascular permeability in rabbit skin, and passive immune hemolysis. Sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis showed that the purified enterotoxin consisted of subunits A and B, identical to those of cholera enterotoxin, and Ouchterlony double gel diffusion tests indicated that the two toxins were immunologically identical. Enterotoxins prepared from several non-O1 strains isolated from human patients were also immunologically identical to cholera enterotoxin.

Biological Assay↗
PubMed1983

Analysis of antigenic determinants in cholera enterotoxin and heat-labile enterotoxins from human and porcine enterotoxigenic Escherichia coli.

Antigenic determinants of cholera enterotoxin (CT) and heat-labile enterotoxin from a human strain (LTh) and a porcine strain (LTp) were analyzed by Ouchterlony double-gel diffusion test against anti-CT, anti-LTh, and anti-LTp, which were treated by immunoaffinity column chromatography. The results showed the existence of the following antigenic determinants: (i) antigenic determinants unique to CT, LTh, and LTp, respectively; (ii) an antigenic determinant common to CT, LTh, and LTp; (iii) an antigenic determinant common to CT and LTh, but not LTp; and (iv) an antigenic determinant common to LTh and LTp, but not CT. On the basis of these results, an antigenic scheme for CT, LTh, and LTp is proposed.

Animals↗
PubMed1983

Evidence that a non-O1 Vibrio cholerae produces enterotoxin that is similar but not identical to cholera enterotoxin.

Cholera-like enterotoxin produced by a non-O1 strain of Vibrio cholerae, S7 (S7 enterotoxin), isolated from human diarrheal stool, was purified, and its physicochemical, biological, and immunological properties were compared with those of cholera enterotoxin from V. cholerae O1 569B (CT) and an enterotoxin produced by another non-O1 V. cholerae (E8498 enterotoxin) reported previously (Yamamoto et al., Infect. Immun. 39:1128-1135, 1983). The purified S7 enterotoxin had physicochemical properties different from those of CT and E8498 enterotoxin. S7 enterotoxin had greater relative mobility in conventional polyacrylamide gel disc electrophoresis and a lower isoelectric point, and its B subunit was smaller than those of CT and E8498 enterotoxin. The results of sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis suggested that the size of the aggregate of the B subunits of S7 enterotoxin is larger than that of CT and E8498 enterotoxin. The biological and immunological properties of S7 enterotoxin were indistinguishable from those of CT and E8498 enterotoxin. These results indicate that non-O1 vibrios may produce more than one kind of cholera-like enterotoxin: one which is identical to CT (E8498 enterotoxin type) and another which is not identical to CT (S7 enterotoxin type).

Animals↗