Search PubMed⌕ Search

Biomedical subjects

G Sakaguchi

Publications and source records attributed to G Sakaguchi.

At least 91 records · Page 5Linked to original sources
PubMed1984

Titration of botulinum toxins for lethal toxicity by intravenous injection into mice.

Clostridium botulinum type A - F toxins can be titrated by the time-to-death method by iv injection into mice. The time to death is not dependent upon the molecular size, but upon the immunological type of the toxin. It is necessary to assure complete activation of the activable toxin produced by nonproteolytic as well as a certain proteolytic strains before subjecting to titration by the iv injection method.

Animals↗
PubMed1983

Purification and characterization of alpha-toxin of Clostridium oedematiens type A.

The alpha-toxin of Clostridium oedematiens type A was purified from culture filtrate by two steps of column chromatography and repeated gel filtration. The purified alpha-toxin proved homogeneous in polyacrylamide gel electrophoresis and agar gel double diffusion. The molecular weight of the alpha-toxin was estimated at 280,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis and at 260,000 by gel filtration on a Sephadex G-200 column. The isoelectric point determined by isoelectric focusing polyacrylamide gel electrophoresis was 6.1. No dissociation of the purified alpha-toxin into subunits was demonstrated in sodium dodecyl sulfate polyacrylamide gel electrophoresis. The 50% lethal and edematizing doses per mg protein of the purified alpha-toxin were 5.9 X 10(4) and 5.9 X 10(5), respectively. The L +/50 doses per mg protein of the toxin was 4.6 X 10(3). The purified alpha-toxin, when injected intradermally into the rabbit skin, induced increased vascular permeability. The toxin contained little or no hemolytic or lecithinase activity. These results attest that the lethal, edematizing and vascular permeability-enhancing activities elicited by C. oedematiens type A culture reside on the same protein molecule.

Animals↗
PubMed1982

Binding to mouse brain synaptosomes of Clostridium botulinum type E derivative toxin before and after tryptic activation.

Clostridium botulinum type E125 I-labelled derivative toxin, both the partially active (intact) and the fully active (nicked) forms, bound to mouse brain synaptosomes. They gave the same KD and Bmax values in binding to synaptosomes, although the nicked form possessed a mouse lethal potency about 30 times higher than that of the intact form. These results may indicate that the binding site of the derivative toxin is not modified by tryptic activation and that the binding to synaptosomes is independent of the blockade of acetylcholine release.

Animals↗
PubMed1982

Production of C2 toxin by Clostridium botulinum types C and D as determined by its vascular permeability activity.

Vascular permeability (VP) activity was demonstrated by intradermal injection of culture supernatants of Clostridium botulinum types C and D and strains producing only C2 toxin. The activity was enhanced markedly by treatment with trypsin. It was abolished by antiserum against C2 toxin and by antisera specific for components I and II of C2 toxin, but not by anti-type C or -type D neurotoxin serum. Of 14 strains examined, 10 had VP activity. No VP activity was demonstrated in the culture supernatants of C. botulinum type A, B, E, or F. These results indicate that VP activity is a function of the C2 toxin elaborated by C. botulinum types C and D and that the toxin possesses VP as well as lethal activities. These findings raise the possibility that VP activity of C2 toxin exerts synergic effect(s) with neurotoxin in the pathogenesis of botulism caused by type C and D strains.

Animals↗
PubMed1982

Experimental production of staphylococcal enterotoxins A, B, and C on rice flour gel medium.

Production of staphylococcal enterotoxins A, B, and C was studied on the rice flour gel plate consisting of rice flour and distilled water devised by the authors simulating cooked rice that has commonly been incriminated for staphylococcal food poisoning in Japan. Enterotoxin produced on the rice flour gel plate was determined quantitatively by reversed passive hemagglutination. The rice flour plate supported production of fairly large quantities of enterotoxins A, B, and C. The rice flour concentration of the plate and the quantity of the surface water largely affected the enterotoxin production. The largest amount of enterotoxin, 0.2-0.4 mg/25-ml plate, was produced in 3 days at 37 C on 16% rice flour gel plates overlaid with 4 to 8 ml of saline. It appeared that the production of enterotoxin A was more rapid than that of enterotoxin B or C.

Culture Media↗
PubMed1981

Vascular permeability activity of botulinum C2 toxin elicited by cooperation of two dissimilar protein components.

Botulinum C2 toxin has vascular permeability as well as lethal activities. Both activities are elicited by cooperation of two dissimilar protein components, designated components I and II, which individually have very low activities. The vascular permeability activity of C2 toxin, demonstrated as blueing response after intravenous injection of Evans blue, was markedly enhanced by treatment with trypsin and was abolished by neutralization with either anti-component I or II serum. Inflammatory reactions, such as edema, congestion, and hemorrhage, were found at the site of intradermal injection of trypsinized C2 toxin. No vascular permeability activity was demonstrated by the intradermal injection of the toxin of Clostridium botulinum types A through F. These results indicate that C2 toxin has a novel biological activity, which is not possessed by the neurotoxin elaborated by C. botulinum types A through F. This suggests that C2 toxin causes lethality in a different way from that of botulinum neurotoxin, which is known to inhibit the presynaptic release of acetylcholine at the neuromuscular junction.

Animals↗
PubMed1981

Separation of Clostridium botulinum type A derivative toxin into two fragments.

Two fragments with molecular weights of 105,000 (fragment I) and 58,000 (fragment II) were separated chromatographically from each other after Clostridium botulinum type A derivative toxin adsorbed onto a QAE-Sephadex column was treated with dithiothreitol and urea. They were antigenic and formed crossing precipitin lines against anti-derivative toxin in agar gel diffusion tests. Upon removal of dithiothreitol and urea by dialysis, the two fragments reassembled to reconstruct the derivative toxin molecule.

Animals↗
PubMed1980

Oral toxicities of Clostridium botulinum type C and D toxins of different molecular sizes.

Clostridium botulinum type C progenitor toxins of different molecule sizes, C-L (16S) and C-M (12S), were purified from cultures of strains 573, Stockholm, and CB-19. C-L toxin showed some hemaggglutinin activity, whereas C-M toxin did not. Neither C-L nor C-M toxin was activated upon trypsinization. Molecular dissociation of purified type C-L and C-M toxins into toxic and nontoxic components was demonstrated by sucrose density gradient ultracentrifugation and diethylaminoethyl-Sephadex chromatography at pH 8.0. The molecular construction of type C progenitor toxin appears to be analogous to that reported for botulinum toxins of other types. C-L and D-L toxins showed higher oral toxicities to mice than did C-M or D-M toxin. Such higher oral toxicities were ascribed to the higher stabilities of these toxins in gastric and intestinal juices.

Administration, Oral↗
PubMed1980

Evidence that botulinum C2 toxin has two dissimilar components.

Botulinum C2 toxin produced by most toxigenic and nontoxigenic strains of Clostridium botulinum types C and D contains two distinct protein components, and these were separated by ion-exchange chromatography and gel filtration. Neither of these components manifested the original toxicity, but the original toxicity was restored when the two components were mixed together and trypsinized. This indicates that C2 toxin consists of two dissimilar protein components and that the cooperation of the two is required to elicit toxicity.

Animals↗
PubMed1980

Purification and characterization of two components of botulinum C2 toxin.

Two dissimilar proteins, designated as components I and II, of botulinum C2 toxin elaborated by strain 92-13 were purified to a homogeneous state. The molecular weights determined by sodium dodecyl sulfate gel electrophoresis were 55,000 for component I and 105,000 for component II. Whereas each component showed no or feeble toxicity even after being treated with trypsin, the toxicity was elicited when these two components were mixed and trypsinized. The toxicity of the mixture of components I and II at a ratio of 1:2.5 on a protein basis was 2.2 X 10(4) mouse intraperitoneal 50% lethal doses per mg of protein and increased by 2,000 times or more when treated with trypsin. These results indicate that the molecular characteristics of botulinum C2 toxin differ from those of the toxin of Clostridium botulinum types A through F in that C2 toxin is constructed with two separate protein components, which are not covalently held together, and that its toxicity is elicited by cooperation of the two components.

Botulinum Toxins↗
PubMed1980

Prevalence of Clostridium botulinum in fishes from markets in Osaka.

A total of 142 samples of different sea foods, mostly fish, were procured from the near-by supermarkets to examine the edible parts for the presence of Clostridium botulinum. Eleven samples (7.7%) seemed to contain this organism. Of these samples, we identified the toxin type in seven; six were type C and the other one type D. Isolation of C. botulinum type C was successful form the six samples but that of type D failed.

Animals↗