Fatty acid profiles in the family Leptospiraceae.

Fatty acid profiles of six leptospira strains representative of genera, species, and serogroups within the family Leptospiraceae were determined by gas liquid chromatography (GLC) of fatty acid methyl ester (FAME) derivatives. The influence of methodological and biological variables on FAME profiles of the same strain was tested. FAME profiles were sharply affected by the fatty acid composition of the culture medium but not by the growth phase. Twenty-four FAME peaks were selected on the basis of their presence in repeated gas chromatographic runs of single strains. Inter-strain divergences of FAME profiles were quantified by linear regression analysis (LR). Step-wise divergences in FAME profiles were observed between strains at serogroup, species, and genus levels.

Analysis of the axial filaments of Treponema hyodysenteriae by SDS-PAGE and immunoblotting.

Purified axial filaments from eight serotypes of Treponema hyodysenteriae and two non-pathogenic intestinal spirochaetes were characterized by SDS-PAGE and Western blotting. Axial filaments of all ten strains had similar SDS-PAGE profiles; five major axial filament polypeptides were identified, with molecular masses of 43.8, 38, 34.8, 32.8 and 29.4 kDa. Hyperimmune gnotobiotic pig serum raised against purified axial filaments of strain P18A (serotype 4) cross-reacted with all other serotypes and with the non-pathogens, and convalescent serum taken from a pig with persistent swine dysentery also showed a strong response to the axial filament polypeptides. Hyperimmune gnotobiotic pig serum raised against axial filaments failed to agglutinate viable organisms and did not inhibit growth in vitro. Hence, the axial filaments of T. hyodysenteriae have been identified as major immunodominant antigens, although the role that antibodies to these antigens play in protection has yet to be established.

Chemical compositions of cell walls and polysaccharide fractions of spirochetes.

Cellular polysaccharide fractions of various representative members of genera of the family Spirochaetaceae were obtained by the ammonium hydroxide extraction method. The sugar composition of the polysaccharide preparations was complex and many kinds of sugars such as rhamnose, fucose, ribose, xylose, mannose, galactose, and glucose were detected in all of the spirochetes tested. Of particular interest was the presence of 4-O-methylmannose as a constituent polysaccharide in members of the genus Leptospira. This sugar was not detected in the polysaccharides of Spirochaeta, Borrelia, and Treponema. The chemical compositions of cell wall fractions were also examined. 4-O-Methylmannose was detected in the cell wall polysaccharides of the genus Leptospira but not in cell walls prepared from the Spirochaeta, Borrelia, and Treponema. The diaminopimelic acid present in cell wall peptidoglycans of the genus Leptospira was meso-diaminopimelic acid (A2pm). The molar ratios of alanine, glutamic acid, A2pm, glycine, muramic acid, and glucosamine in leptospiral cell walls were found to be approximately 2:1:1:1:1:1. In contrast to the Leptospira, the peptidoglycans of genera Spirochaeta, Borrelia, and Treponema contained ornithine (Orn) but not A2pm. Since 4-O-methylmannose and A2pm were found in the cell wall fractions of genus Leptospira but not in Spirochaeta, Borrelia, or Treponema, it was suggested that the chemical compositions of the cell wall might become an important criterion for the chemotaxonomy of Spirochaetales.