Abstract
The inhibiting substance of Bacillus subtilis, strain-Sb 2w against Candida albicans was best demonstrated when Sb 2w was cultivated in the infused solution with 12.5 per cent soybeans, containing 1.0 per cent soluble starch (pH 5.8), at 25℃ for 3 to 5 days. The inhibitory action of Sb 2w against C. albicans in the culture filtrate was stable against heat (100℃ for 10 minutes) at various pH, but it was inactivated after kept for 3 days in the room temperature. The inhibiting substance of this organism was not precipitated from the culture filtrate with acid, but it was able to obtained as the crude material by absorption method with active carbon, or to dissolved into organic solvents (acetone or methanol), from the culture filtrate. This crude material which was obtained from the culture filtrate of Sb 2w showed no toxicity for mice given 29 mg solution in 3 days 8 divided injection. The inhibiting action of this crude material was not inactivated by human's blood serum, as well as the haemolysis of rabbit's blood cell. Candida albicans acquired relatively slight resistance to inhibiting activity of Sb 2w after 7 transinoculation in the medium, containing crude material of the inhibiting substance, but this resistance of Candida albicans could easily be returned to the original sensitivity after 15 transfers in the same medium. The crude material of inhibiting substance was fractionated with paper chromatography, and inhibiting spot was found at 0.47 to 0.50 of Rf, and the spot on Millon's test was positive in various reactions.
