SEQUENTIAL GENE ACTION IN THE ESTABLISHMENT OF LYSOGENY

A study of temperature sensitive clear-plaque-forming mutants of bacteriophage P22 demonstrates that the c(1) and c(2) loci must function in a temporal sequence in the establishment of lysogeny in Salmonella typhimurium. The c(1) locus acts for only a 4-minute interval between the 7th to 11th minute of the infection. The c(2) locus begins to function some minutes later, and its continued activity is necessary for perpetuation of the lysogenic state.

DIFFERENCES IN ANTIBODY RESPONSE OF RABBIT TO INTRAVENOUSLY INJECTED SOLUBLE AND CELL-ATTACHED ENTEROBACTERIAL ANTIGEN

A study was made of the antigenicity of soluble and cell-attached common antigen obtained from enteric bacteria. This antigen becomes readily attached to erythrocytes, which become agglutinable in the presence of the corresponding antibody. Although the common antigen is extractable from numerous species and serogroups of Enterobacteriaceae, in only a few, notably Escherichia coli O14, does it engender antibodies in the rabbit upon intravenous injection. It is shown that antibodies against the common antigen are produced after intravenous injection of cell-attached antigen from E. coli O111, Salmonella spp. and Shigella spp. but not, or only slightly, after administration of soluble antigen. Antibodies are also formed after injection of antigen attached to C3H mouse fibroblast (L) cells. Intravenous injection of equivalent amounts of common antigen from E. coli O14, E. coli O111, S. typhi-murium and S. flexneri results in antibody formation against the common antigen only with that from E. coli O14.