1959 Volume 19 Issue 6 Pages 554-563
Mutabile-type variants were obtained from each 20 strains of E. coli, each 25 strains of paracoli-type E. coli and their lactose variants, as well as from each 5 strains of so-calledd paracolon Aerobacter and their lactose variants.
Growth inhibiting power of raffinose was determined by the paper-disk method used in the author's laboratory.
Growth ihnibiting power of raffinose on Mutabile-type variant was analized in order to know its causal relationship to the raffinose f ermentability or non-fermentability of the starting strain.
Experimental results obtained were as follows :
Mutabile-type variants derived from the mother-cells which ferment raffinose within a day or two -and half of the variants derived from the raffinose non-fermenting mother cells demonstrated nearly the same degree of growth inhibition by raffinose. While half of the latter group demonstrated no inhibition zone even by raffinose in a concentration of 10, 000γ/0.01 ml.
Therefore, it is believed that if the original starting strain ferments rathnose, the Mutabile-type variants originated from it are influenced by raffinose more frequently than those originated from the non-fermenting one.
Growth inhibitory action of galactose is seen on all the strains tested, but that of lactose is not, and that of raffinose is still more complicated. This action of galactose part on Mutabile-type variants seems to be greatly dependent on the structural complexity of the galactoside used. Further details on this problem will be discussed in another paper.
