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K Oguma

Publications and source records attributed to K Oguma.

At least 163 records · Page 9Linked to original sources
PubMed1976

The stability of toxigenicity in Clostridium botulinum types C and D.

Several type C and D strains of Clostridium botulinum, which had been converted to the toxgenic state by phages, were serially transferred through cooked meat medium with and without specific anti-phage serum. Most of the converted strains lost their toxigenicity even during transfer without antiserum, and the non-toxigenic variants that appeared were resistant to lysis and conversion by the original phage. However, in some combinations of phage and host bacteria toxigenicity was stable after ten transfers, though it showed a transient decrease, and the non-toxigenic variants that arose remained sensitive to lysis and conversion. When converted strains were transferred in medium containing anti-phage serum, toxigenicity was lost more rapidly than in the absence of serum and the non-toxigenic variants that appeared remained sensitive to lysis and conversion by the parent phage. Filtrates of the supernatants of culture fluids of strains transferred without anti-phase serum converted non-toxigenic strains to toxigenicity at varying rates.

Antibodies, Viral↗
PubMed1976

Antigenicity of converting phages obtained from Clostridium botulinum types C and D.

Phage conversion of toxigenicity in Clostridium botulinum types C and D was accomplished by using nontoxigenic strains and phages purified from plaques. Although the morphology of the converting phages seemed to be the same, they were divided into three groups on the basis of their conversion spectrum. The first group consists of phages obtained from toxogenic strains C-Stockholm and C-468. The second group consists of phages from strains D-1873 and C-203. The third group consists of phages from strains D-South African and D-4947. These converting phages were also classified into the same three groups by a neutralization test with specific antiphage sera. Cross-neutralization, however, was observed between phages belonging to group 1 and group 2,by both the neutralization test of converting ability and by a plaque experiment in which the surviving rates of phages were calculated after treatment with each antiphage serum. The antigenic differences among these converting phages should probably comprise one of the reasons for the existence of the specific infection spectrum in C. botulinum types C and D.

Antigens, Viral↗
PubMed1976

Phage conversion to hemagglutinin production in Clostridium botulinum types C and D.

Five toxigenic strains of Clostridium botulinum types C and D were incubated at 37 degrees C for 7 days in 15 ml of the following media: LYG medium, cooked-meat medium, egg meat medium, and N-Z-amine medium. The supernatants of these cultures were tested for hemagglutinin production with 1% erythrocytes obtained from mice, guinea pigs, chickens, sheep, monkeys, and humans. Four toxigenic strains produced hemagglutinin. The highest hemagglutinin titer was obtained with a combination of human erythrocytes and cultures incubated in LYG medium. When the same experiment was carried out with many nontoxigenic strains, hemagglutination was observed in only one strain, C-N71. Strains producing hemagglutinin also produced phages. The phages obtained from toxin- and hemagglutinin-producing strains converted nontoxigenic indicator strains to produce both toxin and hemagglutinin. The phage obtained from a toxin-positive hemagglutinin-negative strain could only induce cultures to produce toxin, and the phage from a toxin-negative hemagglutinin-positive strain could only induce production of hemagglutinin. These studies suggest that the production of hemagglutinin by C. botulinum types C and D is governed by bacteriophages and that hemagglutinin production can be transmitted separately or concomitantly with toxin production.

Bacteriophages↗
PubMed1975

Observations on nonconverting phage, c-n71, obtained from a nontoxigenic strain of Clostridium botulinum type C.

A nontoxigenic mutant (C-N71) obtained from a toxigenic strain of Clostridium botulinum type C, Stockholm, with nitrosoguanidine treatment was found to be lysogenic by the lysis test. Although the filtrate of a passaged lysate of this nontoxigenic but lysogenic strain, C-N71, lysed cells of the nontoxigenic strain C-AO2 equally as well as the converting phage c-st obtained from the strain C-Stockholm, it did not convert C-AO2 to the toxigenic state. The lysis spectrum of this filtrate was the same as that of the c-st phage. The ability of the filtrate to lyse the indicator cells, C-AO2, was destroyed neither by trypsin nor DNase but was inactivated by heat treatment at 80 C for 10 min. This suggested that the agent which caused lysis was not boticin but probably a phage. An electron micrograph of the complete phage, c-n71, which was similar in morphology to that of the c-st phage was obtained from the filtrate of strain C-N71. Anti-c-n71 phage rabbit serum neutralized both the lytic and the converting activities of the c-st phage. These findings strongly suggest that the c-n71 phage is a mutant of the c-st phage which lacks the gene controlling production of botulinum type C toxin.

Acridines↗