Abstract
In the previous paper, the author reported that in Salmonella group E the strains having the antigen of subgroup E2 were transformed into E3 by the autolysate of bacteria of E3 and that in this phenomenon two different bacteriophages were thought to participate. This paper is an investigation of the relationship between these two bacteriophages and the transforming agent. Their properties will be compared with those of e phage reported by Iseki and Sakai.
Two bacteriophages participating in antigenic transformations O-3.10→O-3.15 and O-3.15→O- (3). (15).34 were purified to discover the transforming agent, which was concluded to be the phage itself.
The two phages were completely different and unrelated both biochemically and serologically. ε15, which was considered responsible for O-3.10→O-3.15 was found to be identical with ε. The other phage found by the author and considered responsible for O-3.15→O- (3). (15).34 was designated as ε34. This is a spherical particle 26-40 mμ in diameter, which resists 80°C for 20 minutes, but is inactivated at 80°C for 30 minutes. It is stable at pH 2.4-12.0 and inactivated at pH below 2.2 and above 12.5. The host range was limited to strains possessing antigens of subgroup E2. ε34 transformed the strains having antigen of subgroup E2 into that of E3. It could not directly transform the strains having antigens of E1 and E4 into that of E3, but could by two steps with the help of ε15. The percentage of cells which had antigen transformed by the infection of ε34 was from 2.6 to 10.3%.
This antigenic transformation can not be explained by spontaneous mutation selection by phage and evidently differs from transformation in the pneumococcus and transduction. Bacteria having the antigen of subgroup E3 were doubly lysogenic. Prophages of ε15 and ε34 in the cell are considered to govern the production of O-15 and O-34 antigens.
