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Biomedical subjects

G Sakaguchi

Publications and source records attributed to G Sakaguchi.

At least 127 records · Page 7Linked to original sources
PubMed1977

Development of antitoxin with each of two complementary fragments of Clostridium botulinum type B derivative toxin.

Two fragments with molecular weights of 111,000 (fragment I) and 59,000 (fragment II) were separated from each other by gel filtration of dithiothreitol and urea-treated, trypsinized derivative toxin (molecular weight, 170,000) of the proteolytic Okra strain of Clostridium botulinum type B on a column of Sephadex G-200 (superfine) with a buffer containing dithiothreitol and urea. Upon removal of dithiothreitol and urea by dialysis, the two fragments reassembled to reconstruct the derivative toxin molecule. Both fragments were immunogenic, and both anti-fragments neutralized type B toxin. The neutralizing activities of both anti-fragment I and anti-fragment II were, however, lower than that of the anti-derivative toxin, suggesting that the molecular integrity of derivative toxin is essential for sufficient production of the neutralizing antibody. The immunological difference found between type B toxin from a proteolytic strain and that from a nonproteolytic strain was ascribed to the antigenic difference of fragment I.

Animals↗
PubMed1977

Response of type B and E Botulinum toxins to purified sulfhydryl-dependent protease produced by Clostridium botulinum type F.

A sulfhydryl-dependent protease (SHP) was purified from a culture of Clostridium botulinum type F. The enzyme can activate type E progenitor toxin completely but type B progenitor toxin only partially. This may suggest that SHP by itself could completely activate the toxin of proteolytic C. botulinum types A and F in culture. The toxicity of type E progenitor toxin potentiated by the treatment with SHP persisted, whereas that of derivative toxin decreased rapidly by further incubation with SHP. This may indicate that only the progenitor toxin, the complex of the toxic and nontoxic components, activated by SHP withstands the subsequent exposure to the enzyme in cultures of proteolytic C. botulinum.

Amidohydrolases↗
PubMed1976

Comparison of progenitor toxins of nonproteolytic with those of proteolytic Clostridium botulinum Type B.

A nonproteolytic strain of Clostridium botulinum type B produces two toxins of different molecular weight (16S and 12S) that are indistinguishable from the corresponding toxins of a proteolytic strain in molecular weight and construction but differ in potential toxicity, activation ratio, and hemagglutinability. Successful hybridization between the toxic and nontoxic components (both7S) of 12S toxins of biologically heterologous type B strains confirmed the physico-chemical similarity between the toxic as well as the nontoxic components.

Botulinum Toxins↗
PubMed1975

Molecular construction of Clostridium botulinum type F progenitor toxin.

Molecular dissociation of purified type F progenitor toxin with an S20,W of 10.3 and a molecular weight of 235,000 into two components, toxic and atoxic, was demonstrated by ultracentrifugation, gel filtration, and diethylaminoethyl-Sephadex chromatography at pH 7.5. The ultracentrifugal analysis indicated that type F progenitor toxin dissociates into components of the same molecular size of 5.9S. The toxic component contained a toxicity of 2.5 times 10-8 50% lethal doses per mg of N. Much higher stability of progenitor toxin than that of derivative toxin, particularly at pH below 5, suggests that only progenitor toxin can act as an oral toxin.

Botulinum Toxins↗
PubMed1975

Antigenicites of fragments of Clostridium botulinum type B derivative toxin.

Two fragments with molecular weights of 110,000 and 60,000 were separated in a preparatory scale by gel filtration of the reduced Clostridium botulinum type B trypsinized derivative toxin on Sephadex G-200 with 0.05 M tris(hydroxymethyl)aminomethane-0.38 M glycine buffer, pH 8.3, containing 5 mM ethylenediaminetetraacetate, 1 mM dithiothreitol, and 2 M urea as eluant. They were both antigenic, forming crossing precipitin lines against type B antitoxin in agar gel double diffusion tests.

Antigens, Bacterial↗
PubMed1975

Molecular construction of Clostridium botulinum type A toxins.

Two Clostridium botulinum type A toxic fractions, named large (L) and medium (M) toxins, were eluted from Sephadex G-200. Sucrose density gradient centrifugation resolved L toxin (2.5 X 10(8) to 3.0 X 10(8) mean lethal doses per mg of N) into two fractions, 19S and 16S. The same procedure performed at pH 8resolved it into three fractions; the heavier two were both nontoxic and hemagglutinin positive, and the lightest on (7S) was toxic. M toxin (12S) (4.5 X 10(8) to 5.0 X 10(8) mean lethal doses per mg of N) was homogeneous in electrophoresis and centrifugation at pH 6. The latter procedure performed at pH 8 dmonstrated that it dissociated into uniform 7S components. The nontoxic component of M toxin was free from hemagglutinin. M toxin alone was demonstrated in culture by sucrose density gradient centrifugation at pH 6. Dialysis of the culture supernatant resulted in partial formation of 16S toxin. Centrifugation of the crystalline toxin in 1 MNaCl demonstrated 16S toxin only. The toxic components of L, M, and crystalline toxins were antigenically identical. The nontoxic components of the crystalline and L toxins, consisting of two distinct antigens, were antigenically identical; that of M toxin was identical with one of these two antigens.

Botulinum Toxins↗
PubMed1975

Responses of Clostridium botulinum type B and E progenitor toxins to some clostridial sulfhydryl-dependent proteases.

Sulfhydryl-dependent proteases produced by Clostridium botulinum types A, B, and F, Clostridium histolyticum, Clostridium sporogenes and Clostridium perfringens activate preferentially type E over type B progenitor toxin but less efficiently than trypsin. The results explain why activable toxin is demonstrable in culture of a strongly proteolytic type B strain.

Botulinum Toxins↗
PubMed1975

Experimental diarrhea in cynomolgus monkeys by oral administration with Clostridium perfringens type A viable cells or enterotoxin.

Purified C. perfringens type A enterotoxin fed orally in an amount of 5 mg caused both vomiting and diarrhea in the monkey only when the gastric juice had been neutralized. Exposure of enterotoxin to pH 4.0 or below rapidly destroyed the activity. All three monkeys receiving sodium bicarbonate and 2.4 X 10(10) viable cells grown in DS medium developed diarrhea, and only one of them vomited once. The diarrhea lasted for 13, 18 and 19 hr. The symptoms were similar to those reported in human cases of C. perfringens food poisoning. These results have verified the general notion that C. perfringens food poisoning should be categorized as a true "intravital intoxication". The reversed passive hemagglutination test detected enterotoxin directly in most fecal samples. This method may be applicable for diagnosis of human cases of C. perfringens food poisoning. Neither enterotoxin nor anti-enterotoxin was detected in serum samples taken from any monkey up to 21 days after the challenge. We are tempted to conclude, therefore, that no significant amount of C. perfringens enterotoxin is absorbed from the intestine.

Administration, Oral↗
PubMed1974

Purification of Clostridium botuliunum type F progenitor toxin.

Clostridium botulinum type F progenitor toxin was purified to a homogeneous state as judged by gel filtration on Sephadex G-200, ultracentrifugation, and disc electrophoresis. The sedimentation constant, corrected to water at 20 C, of type F progenitor toxin was determined to be 10.3 and the molecular weight to be 235,000 by ultracentrifugation at pH 6.0. The purified toxin contained a toxicity of 1.2 x 10(8) 50% lethal doses/mg of N. In agar gel double diffusion, it formed two precipitin lines at pH 6.0. The progenitor toxin of type F differs from that of type A in that it contains no hemagglutinin and from that of type E in that it is not activable.

Ammonium Sulfate↗
PubMed1974

Purification and some properties of progenitor toxins of Clostridium botulinum type B.

Purification of progenitor toxin of Clostridium botulinum type B strain Okra was undertaken by sequential steps of acid precipitation, extraction, ammonium sulfate precipitation, ribonuclease digestion, acid precipitation, protamine treatment, sulphopropyl-Sephadex chromatography, and Sephadex G-200 gel filtration. Two different molecular-sized toxins, named large (L) and medium (M) toxins, were obtained. L toxin was centrifugally homogeneous but electrophoretically heterogeneous. It contained 2.5 x 10(8) to 3.0 x 10(8) mean lethal doses per mg of nitrogen, and its sedimentation constant was 16S. M toxin was centrifugally and electrophoretically homogeneous. It contained 5.5 x 10(8) to 6.0 x 10(8) mean lethal doses per mg of nitrogen, and its sedimentation constant was 12S. The presence of both L and M toxins in spent culture was demonstrated. It seems justified, therefore, to call both progenitor toxins. Both consisted of toxic and nontoxic components. The toxic components of L and M toxins appeared to be identical with each other. The nontoxic component of L toxin was 12S and possessed a hemagglutinin activity of about 0.5% that of type A crystalline toxin; that of M toxin was 7S and possessed no hemagglutinin activity. They were antigenically related but not identical.

Animals↗