粘液型ムタビール (村瀬のM由来) のgalactose取り込みについて

抄録

Mucoid M, a mutant originating from Mutabile-type Var. of Murase, was cultured on galactose agar and Mucoid RT, a mutant being deprived of the M character of Mucoid M, on nutrient agar. The developed slime was collected, dialyzed against running tap water and dried. Bacterial cells were processed in the same way to prepare a similar dry material. These materials were hydrolyzed with sulfuric acid. The hydrolyzed were neutralized with barium hydroxide and dried again. Determinations for sugars with special reference to galactose were carried out on these materials. The strains for preparing these materials were mutants of S. typhi-murium RD 1819 and E. coli 3.
The results obtained may be summarized as follows:
1) The hydrolyzates of the slime formed clear inhibition zones against M when assayed by the cup-plate microbiological method of Fukutome et al., while MT (a galactose resistant mutant of M) formed many colonies in the inhibition zones. The formation of inhibition zones was not influenced by fermentation of the sample by the galactose non-fermenting MT. Paper chromatography showed a galactose spot in the sample treated with MT.
These results indicate that formation of the inhibition zoned by the slime hydrolyzate may be dependent upon the presence of galactose in it.
2) The concentration of the inhibiting substance in the slime hydrolyzate obtained from either S. typhi-murium or E. coli was 6.4 % when determined by the cup- or disc-plate method with M as the test organisms. As to the materials originating from Mucoid RT, the corresponding figures were 6.4-12.8 % for S. typhi-murium and 6.4 % for E. coli.
3) Two dimensional paper chromatography demonstrated the presence of, at least, glucose, rharnnose, arabinose and mannose (from Mucoid RT only) in addition to galactose.
4) The dried slime obtained from the Mucoid M grown on galactose agar added with galactose-1-¹⁴C contained a high activity. Such a material was hydrolyzed and separated by paper chromatography. The highest count was detected in the area which corresponded to the spot containing the total activity when a mixture of galactose-1-¹⁴C and a non-labeled hydrolyzate was separated under the same conditions.
5) A large portion of the count in the culture of Mucoid M was detected in the slime. The ratio of the count in the dry material from the bacterial cells to that from the slime was calculated to be about 1: 10.
6) The count in the material from M or MT was much lower than that in the material from mucoid types.
7) Approximately the same count was detected in the slime and in the bacterial cell materials from Mucoid RT.
8) From the foregoing results, it may be concluded that Mucoid M, which is believed to be impossible to synthesize galactose because of the enzymatic defect takes free galactose added to the medium and synthesize the slime layer from it probably through galactose-l-phosphate-UDP galactose.
This conclusion is supported also by the finding that galactose in the combined form is contained as a constituent in the slime of Mucoid M. The fact that the slime is not formed unless galactose is available may indicate the necessity of galactose for synthesis of the slime of Mucoid M.
Another fact that the same proportion of count was detected in the slime and in the bacterial cells of Mucoid RT may be explained by the assumption that ¹⁴C had been transferred to different metabolic cycles of galactose and therefore the ratio of ¹⁴C deposited in other parts than the slime may have been larger than in Mucoid M.