Abstract
Mutabile type variant of Murase (M-type variant) was isolated, as reported by Numata, from the old broth cultures of the several strains of Salmonela typhi (V or VW form), and galactose fermenting daughter of Fukutome et al (RT variant) was isolated from this variant availing galactose peptone water cultures in dilution method. This variation from M-type variant to RT has already been confirmed by Fukutome et al in other species of bacteria.
Antigenically, M-type variant, its galactose fermenting daughter RT variant and galactose non-fermenting daughter MT variant were found to possess O, H and Vi antigens in common with their starting original strain. Further, the presence of Vi capsules too was confirmed on all of the above strains by Ando's staining method.
But a paradoxical phenomenon was observed on their virulence in mice. Namely, the virulence of the original type and RT variant was strong while the virulence of M-type variant and MT variant was weak, when mucin bacterial suspensions were used.
In other words, M-type variant was different from its starting original type on the points that its virulence in mice is weak, the colonies formed on agar plate are rough and its growth is inhibited by galactose, etc.
On the contrary, RT variant presented the biological characters exactly the same as those of the starting original type. Therefore, this RT variant is considered to be a so-called in vitro reverse mutant of M-type variant to its original type.
Discussions on this variation will be supplemented in the following report.
