CHARACTERIZATION OF 3 PUTATIVE SERPULINA-HYODYSENTERIAE HEMOLYSINS

Serpulina hyodysenteriae hemolysin is thought to be an important virul ence factor in swine dysentery. One gene, tlyA, previously called tly, encoding a hemolysin in S. hyodysenteriae strain B204 has been charac terized (Muir et al. infect Immun 1992; 60: 529-35). Two other genes o f S. hyodysenteria strain B204, designated tlyB and tlyC, encoding hem olytic proteins in Escherichia coli strain DH5 alpha were cloned and s equenced. The tlyB and tlyC genes, when expressed in E. coli, encode h eat-labile, protease-sensitive proteins which exhibit both hemolytic a nd cytotoxic activity in vitro. The calculated molecular weights of th e tlyB and tlyC gene products are 93.3 kDa and 30.8 kDa, respectively. The tlyB gene product has sequence homology with the Clp proteins, wh ereas for the tlyC-encoded protein no homology with other protein sequ ences was observed. Southern hybridization showed that the tlyB and tl yC genes are present in a single copy on the chromosome of S. hyodysen teriae.