Abstract
So-called mucoid M and mucoid RT mutated from the Mutabile-type Var. (Murase) which was obtained from the old broth cultures of Salm, typhi-murium, Salm, enteritidis and E, coli do not grow on 0.5-1% sodium sulfite agar. Their growths are completely inhibited in both surface and deep cultures. On the contrary, the original strain, Mutabile-type Var., the RT mutated from the Mutabile-type Var. and a very small part of mucoid RT are not inhibited by the above dose of sodium sulfite. If both kinds of organisms are mixed and present in the same culture, only resistant strains would grow on this medium.
Mucoid variants mutated directly from the original type of Salm, typhi-murium and that of Salm. enteritidis were resistant to sodium sulfite, but a mucoid variant of Sh, flex. 4a was susceptible.
From the above experiments, it was found that the growth of mucoid M and mucoid RT are specifically inhibited when plated on to sodium sulfite medium.
Utilization of this phenomenon may enable to know the rate of mucoid M→nonmucoid M, mucoid M→mucoid RT, and mucoid RT→nonmucoid RT mutation.
Directions and orders of the mutation of such variants have already been investigated in the authers laboratory.
