Abstract
Recent investigations have shown that sodium cyclamate (CHS-Na) can be metabolized to cyclohexylamine (CHA) by certain species of intestinal bacteria inhabiting the gut of animals and man, but the CHS-Na converting bacteria were not clearly identified.
Entero-bacterial formation of CHA in rabbits and guinea pigs was investigated chemically in animals surgically intubated into the cecum with the feces of CHS-Na converter monkeys under long-term feeding with CHS-Na. To obtain CHS-Na converting bacteria in vivo and in vitro, microbiological studies were carried out on the intestinal contents and feces of normal and converter animals. Feeding experiments were conducted in two diet groups: rabbits and guinea pigs were given appropriate standard commercial diet or the monkey diet alone. 1) Normal rabbits and guinea pigs that were given 0.5g of converter monkey feces intragastrically became converter animals in 1 to 3 days under continuous feeding with CHS-Na. 2) CHS-Na conversion seemed to be enhanced in rabbits and guinea pigs fed the commercial monkey diet alone instead of appropriate commercial diets. 3) In rabbits and guinea pigs that had switched from normal to converter status, no significant changes of fecal and cecal microflora were obserbed among Bifidobacterium, Peptostreptococcus, Veillonella, Lactobacillus, Streptococcus, Enterobacteriaceae, Staphylococcus, molds and yeasts, but slight changes were found in Clostridium sp., Propionibacteriaceae and Bacteroidaceae. 4) CHS-Na conversion ability was determined chemically and microbiologically in mass cultures of these intestinal flora. In vitro experiments suggested that some specific bacteria belonging Clostridium sp., Propionibacteriaceae and Bacteroidaceae may have CHS-Na conversion activity.
Taxonomical studies with these strains at the species level are in progress.
