STRUCTURE OF 16S AND 23S RIBOSOMAL-RNA GENES IN CAMPYLOBACTER SPECIES- PHYLOGENETIC ANALYSIS OF THE GENUS CAMPYLOBACTER AND PRESENCE OF INTERNAL TRANSCRIBED SPACERS

16S and 23S ribosomal RNA (rRNA) genes from campylobacteria were studi ed by polymerase chain reaction and DNA sequence analysis using univer sally conserved oligonucleotide primers. In the 16S rRNA gene sequence s of all C. sputorum strains tested, an insertion oi about 250 bp was found that was not present in the 16S rRNA genes of other Campylobacte r species. This insertion was not present on the rRNA level in C. sput orum, and the 16S rRNA was found to be fragmented in this organism. Fr om the length of the fragments, it could be concluded that the inserti on is an internal transcribed spacer, which is probably excised during rRNA maturation. Similar internal transcribed spacers were also found in the 23S rRNA genes from several Campylobacter strains. On the basi s of partial 23S rRNA gene sequences about 875 bp in length and compri sing some of the most variable helices, phylogenetic analysis was perf ormed on 17 Campylobacter strains. The results of this analysis were c ompared to a phylogenetic tree based on complete 16S rRNA sequences.