2 TYPES OF 16S RIBOSOMAL-RNA GENE ARE FOUND IN CAMPYLOBACTER-HELVETICUS - ANALYSIS, APPLICATIONS AND CHARACTERIZATION OF THE INTERVENING SEQUENCE FOUND IN SOME STRAINS
D. Linton et al., 2 TYPES OF 16S RIBOSOMAL-RNA GENE ARE FOUND IN CAMPYLOBACTER-HELVETICUS - ANALYSIS, APPLICATIONS AND CHARACTERIZATION OF THE INTERVENING SEQUENCE FOUND IN SOME STRAINS, Microbiology, 140, 1994, pp. 847-855
In the recently described species Campylobacter helveticus, two sizes
of PCR amplicon were detected with primers homologous to conserved reg
ions of the 16S rRNA gene. A conventionally sized gene was sequenced f
rom the type strain, NCTC 12470, placing the new species as phylogenet
ically related to C. upsaliensis and the thermotolerant campylobacters
. This nucleotide sequence enabled PCR primers to be designed for use
in rapid molecular identification of C. helveticus and its closest phy
logenetic relative, C. upsaliensis. When this assay was employed to ch
aracterize 22 'C. upsaliensis-like' isolates, twelve were identified a
s C. helveticus and nine as C. upsaliensis, in agreement with data obt
ained with a C. helveticus-specific DNA probe. A 550 bp amplicon inter
nal to the 16S rRNA gene of C. helveticus was used to determine restri
ction fragment length polymorphisms (RFLPs) in genomic Southern blots,
confirming that the copy number of the C. helveticus gene was three,
and identifying nine 16S rRNA gene profiles. In 5/12 C. helveticus iso
lates identified by PCR, an enlarged amplicon was detected. The enlarg
ed 16S rRNA gene of one of these strains, NCTC 12838, was sequenced an
d shown to contain an atypical intervening sequence (IVS) of 148 nucle
otides. The position and size of such an IVS was inferred in the other
four isolates by PCR with primers 5' and 3' to its position in NCTC 1
2838. This is a first report of an IVS in the 16S rRNA gene of a eubac
terium.