MOTILITY AND CHEMOTAXIS IN SERPULINA-HYODYSENTERIAE

Chemotactic- or motility-regulated mucus association appears to be the predominant mechanism of mucosal association by the causative agent o f swine dysentery, Serpulina hyodysenteriae. In the present study, a m odification of the Adler capillary assay was used to evaluate the chem otactic responses of S, hyodysenteriae to a variety of potential stimu li. First, however, it became necessary to study factors that influenc ed motility of the spirochete in vitro, since standard cultivation met hods produced motility inferior to that observed for in vivo grown cel ls. A number of factors were found to influence S. hyodysenteriae moti lity, but of these growth medium and growth phase appeared to be the m ost important. The type and even batch of culture medium also were fou nd to have a significant influence on S. hyodysenteriae motility. Opti mal motility and chemotaxis for S. hyodysenteriae was observed when th e cells were harvested in mid- to late-log phase, and in vivo-like mot ility could be induced by suspending the cells in physiologic saline. S. hyodysenteriae was strongly attracted to hog gastric mucin, certain concentrations of blood, L-fucose, L-serine and other compounds. Sele cted sugars and other amino acids did not serve as chemoattractants fo r S. hyodysenteriae. The chemotactic response of S. hyodysenteriae tow ard L-fucose and L-serine, constituents of mucin, may be important fac tors in the affinity of the spirochete for the mucus in the intestinal tract of swine.