PSEUDOURIDINE FROM CULTURE MEDIA OF AGROBACTERIUM TUMEFACIENS

Cultures of Agrobacterium tumefaciens grown on a synthetic medium containing glucose plus a pyrimidine produced a pyrimidine riboside with unusual chemical properties. This substance was isolated in crystalline form and identified as 5-ribosyluracil (pseudouridine) on the basis of data obtained from ion exchange and paper chromatography, electrophoresis, ultraviolet and infrared spectrophotometry, color reactions, melting point, elementary analysis, hydrazinolysis, and periodate oxidation followed by bromine treatment.

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.