Previously Hatano and Kurokawa reported that the majority of doubly lysogenic strains of C. diphtheriae seemed to be more toxinogenic than singly lysogenic ones. No systematic investigation on the magnitude of toxinogeny of various singly lysogenic strains has been reported yet. This paper deals with the toxinogeny of various lysogenic strains derived from C4, applying a relatively simple technique of toxin-antitoxin reactions in the agar gel. The following results were obtained. 1. There seemed to be a correlation between the toxinogeny and the size of halo formed around the colony grown on an agar culture plate containing antitoxin. This method is both simple and easy to roughly estimate the toxinogeny of strains of diphtheria bacilli. 2. The magnitude of toxinogeny varied with different lysogenic strains, even within strains carrying, the same type of prophage, while the majority of their clones were proven to be stable through several, passages. 3. The magnitude of toxinogeny seemed to be independent of its carrying prophage type, and could not be transfered with the phage to an other strain. Factor or factors that regulated the magnitude of: toxinogeny of lysogenic strains remained undetermined, but it may be probably regulated by host cell itself.
For the purpose to find out the action of plant components on the growth of bacteria, crude juices of 20 kinds of fresh plants were prepared by soaking them separately in hot water for a certain period of time, and the plant juices so obtained were added to the protein-free synthetic medium and test bacteria were cultured in order to observe the manner of bacterial growth. As the results, it was observed that the growth of those bacteria, cultured in the media containing the crude juices of fresh green tea leaves and common ginger root, was poor and these bacteria did not proliferate. On the basis of these observations, the juices of green tea leaves and common ginger root were extracted with alcohol and further fractionated with ether. Next, by mixing these two kinds of fractions to common agar medium and Sabouraud agar medium, Staph. aureus 209-P, oridinal strain, PC, SM-resistant strains of E. coli, Ps. aeruginosa, and Candida family were cultured in order to observe the effects of these fractions on the bacterial growth. The results may be summarized as follows. 1. The ether fraction of green tea leaves showed a very marked inhibitory action on the growth of original strains (both Gram positive and negative), Pc-, SM-resistant strains of E. coli, but no inhibitory action on Candida family. 2. In contrast to this, the ether fraction of common ginger root demonstrated a relatively weaker inhibitory action than that of green tea leaves, and it did not show any inhibitory action on E. coli and Ps. aeruginosa.