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Biomedical subjects

G Sakaguchi

Publications and source records attributed to G Sakaguchi.

At least 145 records · Page 8Linked to original sources
PubMed1973

Assay methods for Clostridium perfringens type A enterotoxin.

Enterotoxin produced by a sporulating culture of Clostridium perfringens type A NCTC 8798 was purified to a level of 3,500 mouse mean lethal doses per mg of nitrogen. High-titer sera were obtained from rabbits injected with enterotoxin and used to compare the sensitivity of serological tests and bioassays for C. perfringens enterotoxin. Reversed passive hemagglutination was by far the most sensitive test, followed by microslide diffusion, single gel diffusion and electroimmunodiffusion, guinea pig skin test, mouse test, and rabbit ileal loop test.

Animals↗
PubMed1973

In vitro production of Clostridium perfringens enterotoxin and its detection by reversed passive hemagglutination.

The reversed passive hemagglutination (RPHA) test yielded a positive reaction in 2 h with as little as 0.5 ng of purified Clostridium perfringens enterotoxin (CPE) per ml as well as with cultures of some C. perfringens grown in Duncan-Strong (DS) medium. This method is the most sensitive, the simplest, and the fastest among all reported. The time course of CPE production of Clostridium perfringens NCTC 8798 in DS was investigated by RPHA. CPE in culture was detectable at 4 h, increased gradually, reached a maximum at 12 to 14 h, and remained at a high level of 20 mug/ml through 48 h of incubation. CPE synthesized within cells is released easily by sonic disruption of young cultures and by aging the cultures 20 h or more. Heat shock of the cell inoculum was essential for CPE production by C. perfringens in DS.

Bacteriological Techniques↗
PubMed1973

Simplified method for purification of Clostridium perfringens type A enterotoxin.

Purification of Clostridium perfringens type A enterotoxin from sporulated cells was simplified. The method consisted of precipitation of the enterotoxin from the extract of sonically treated cells at 40% saturation of ammonium sulfate at pH 7, differential solubilization in 0.02 M phosphate buffer, pH 6.7, and repeated gel filtration on Sephadex G-200. The purified enterotoxin was at least 98% pure in ultracentrifugation, polyacrylamide gel electrophoresis, and agar gel double diffusion. Recovery was over 74% from the sporulated cell extract. The toxin had biological activities of at least 4,700 mouse intravenous minimal lethal doses/mg of N, 3,900 capillary permeability-increasing U/mg of N in the guinea pig skin, and 210 rabbit intestinal loop distension U/mg of N. The toxin, containing no hexose, lipid, or nucleic acid, appeared to be identical in sedimentation constant, isoelectric point, and ultraviolet absorption spectrum to the toxin purified previously by different procedures.

Ammonium Sulfate↗
PubMed1969

Significance of 12S toxin of Clostridium botulinum type E.

The pathogenesis of type E botulism is discussed as an aspect of the physicochemical and biological properties of 12S toxins (prototoxin and trypsin-activated 12S toxin) and the Ealpha and Ebeta components of each 12S toxin. A molecular weight of 350,000 was determined for each 12S toxin and 150,000 for Ealpha and Ebeta. Owing to the structure comprising the subunits Ealpha and Ebeta, 12S toxins are much more stable than Ealpha at low pH values and high temperatures. Such was also the case with type A 19S toxin and its alpha component. The Ealpha component alone accounts for the total toxicity of type E toxin. The toxic substance detected in the blood of the animals administered 12S toxins orally or parenterally was identified as Ealpha from the molecular size and the chromatographic pattern. Prototoxin escaping from detoxification in the stomach owing to the subunit structure may undergo dissociation in the intestine to release the Ealpha component. After absorption, the activated Ealpha appeared in the circulating blood without any further signs of dissociation or enzymatic digestion.

Animals↗