Abstract
So-called crape or rugose colony variant originated from the old broth culture of the mutabile type variant of Murase of Salmonella typhi-murium. The colony grown on the plain agar plate is wet, flat, translucent, larger in size than the ordinary S-type colony and, at first, rich in crapes (especially on the aged culture plate) . The colony grown on 2% citrate agar plate is wet and quite smooth showing a size of ordinary Salmonella colonies.
When cultured in fluid medium, it forms a thin, rather tough pellicle as if supported by a net on slightly turbid fluid medium. While, on the galactose-Endo plate, it forms a common M-type colony of poor growth.
Its galactose sensitivity determined by paper disk method (Fukutome et al.) is similar to that of the original M-type variant.
Galactose resistant daughter colonies in a shape of mushroom are formed on the M-type colony grown on the Endo plate. These daughter colonies form crape colonies on the Endo plate as on the agar plate.
The findings stated above show that the ruga forming charactor acquired or has become apparent in the generation of M-type is inherited by MT through M-MT mutation. Rugose celony variation, however, takes place even in the original genration and RT (reverse mutant of M to the original) .
It may be possible, therefore, to make an inference that a charactor related to the rugose colony variation is transmitted from the original generation to the M-generation in which it suddenly becomes apparent by an unknown cause. From this point of view, the findings of the present study seem to criticize the rugose colony variation in the original type genetically.
