Heterogeneity of human intestinal spirochaetes demonstrated by one-dimensional polyacrylamide gel electrophoresis of proteins visualised by (35)S-methionine labelling and Coomassie blue staining.

The relatedness of strains of a human intestinal spirochaete was investigated by comparison of electrophoretic protein profiles produced by Coomassie Blue staining of proteins separated by polyacrylamide gel electrophoresis (PAGE) of lysed organisms and by examination of autoradiographs following PAGE of lysed (35)S-methionine-labelled organisms. A wide diversity of strains was revealed by both techniques but clustering of strains was different by the two methods. These findings support the view that the human intestinal spirochaetes comprise a group of bacteria of considerable heterogeneity.