Observations on the post-transcriptionally modified nucleotides in the 16S ribosomal ribonucleic acid

The 16S (18S) ribosomal ribonucleic acids from a number of organisms were screened for the presence of (some of) the post-transcriptionally modified oligomers found in Escherichia coli 16S ribosomal ribonucleic acid. All prokaryotic 16S species contained all of the modified oligomers tested, with the sole exception that one such oligomer was missing in Alcaligenes faecalis. The post-transcriptional modifications in all of these oligomers except one appear to occur at the later stagesin ribosomal maturation.