microbiology, Vol 145, 1369-1374, Copyright © 1999 by Society for General Microbiology
A novel protein of Erysipelothrix rhusiopathiae that confers haemolytic activity on Escherichia coli
S Makino, K Katsuta and T Shirahata
Department of Veterinary Microbiology, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
Erysipelothrix rhusiopathiae, the cause of swine erysipelas and human
erysipeloid, produces a haemolysin. A recombinant plasmid, pHLY, conferring
haemolytic activity on Escherichia coli was isolated from a genomic library
of Ery. rhusiopathiae strain Tama-96. This plasmid was stable in RecA- E.
coli, but unstable in a RecA+ strain. A spontaneous deletion plasmid,
pMini-HLY, also conferring haemolytic activity was derived from pHLY. Two
ORFs were detected in pHLY. Analysis of pMini-HLY and other deletion clones
established that ORF2 was associated with haemolytic activity. The sequence
of ORF1 was highly homologous to those of transposases in the IS30 family.
The deletion which generated pMini-HLY was between two short direct repeat
(DR) sequences flanking the ORF1 sequence, and there were inverted repeat
sequences inside the two DR sequences, suggesting an insertion element. No
sequence homology to the deduced amino acid sequence of ORF2 was detected
in the databases, but its sequence was characteristic of a surface
lipoprotein. Western blot analysis, using antiserum against the 16 kDa
protein produced from ORF2, found the protein to be commonly distributed in
all Erysipelothrix species.
