The substance which arises in cultivating mediums by means of the cultivating of Trichophyton rubrum var. nigricans (Fragner 1966) and which has an antibiotic effect on Cryptococcus (Fragner 1965) is not uniform. It is possible to release a basic gas by fast alkalising and warming of the older cultivating medium, which have pH value over 7 owing to the growth of T. rubrum var. nigricans. We determined in this gas dimethylamine by paper and gas chromatography and ammonia by the former of the two methods. The synthetic pure dimethylamine hydrochloride had an antibiotic effect. Our previous (Fragner and Múčka 1966) concentrates obtained by means of distillation were polluted by acrolein arising during dry distillation of glucose from cultivating medium. In younger cultivating mediums with pH ranging from 5.5 to 6.5 there arises — owing to the growth of T. rubrum (with a sharp maximum) — another very unstable substance with antibiotic effect, which we call at the time being “rubronigrin”.
Fragner P., Múčka V. (1969): Experiments on the separation and identification of „Rubronigrin“. – Česká Mykologie 23(2): 127–128.
