Mycoplasma colonies and Mycoplasma cells in preparations from infected milk and lymph nodes were observed for their fluorescent qualities after treatment with acridine orange. Mycoplasma colonies fluoresced brilliant red or red-orange. When treated after exposure to ribonuclease, the colonies fluoresced lime-green. There was no fluorescence when both ribonucleic acid and deoxyribonucleic acid w...

The organization of seven genes located at about 38 min on the genetic map of Escherichia coli was examined; these genes included pheS and pheT, which code for the alpha and beta subunits of phenylalanyl-transfer ribonucleic acid synthetase, and thrS, the structural gene for threonyl-transfer ribonucleic acid synthetase. Deletion mutants were isolated from an F-prime-containing merodiploid stra...

1. Basic dyes (methyl green/pyronin, and toluidin blue), in conjunction with ribonuclease, may be used to detect the cytochemical localization of ribonucleic acid. This technique has been examined critically. 2. The fixative used is important and results vary with different materials. It is suggested that Zenker and Serra fixation should be compared in preliminary investigations. Unexplained an...

The ability of altered transfer ribonucleic acid to compete with binding of [14C]aminoacyland [l*C]tRNA was used as an estimate of its capacity to bind to ribosomes. Transfer ribonucleic acid with the terminal 3’-hydroxyl rA, ,C,A, and ,C,C,A enzymatically removed could bind to 70 S ribosomes with progressively lower efficiency; in contrast, binding to 30 S subunits was unimpaired. Transfer rib...

Preceding publications from this laboratory have shown that the methylation of soluble ribonucleic acid is catalyzed by at least six discrete enzymes (l-3) which have been purified from extracts of Escherichia coli W. Two of these enzyme preparations catalyze the formation of l-methylguanine residues in SRNA,1 while a third produces 7-methylguanine. The others catalyze the methylation of uracil...