Glycosylation of type-IV fimbriae of Dichelobacter nodosus

Dichelobacter nodosus is the causative agent of ovine footrot and the type-IV fimbriae on this bacterium are essential for maintaining its virulence. In this study, we reveal that these fimbriae are glycosylated. This was demonstrated in several ways: by the detection of carbohydrate on fimbrial protein using periodic acid Schiff reagent (PAS) staining of SDS-PAGE gels and by demonstrating enzymatic deglycosylation and by analysis of the amino acid sequences derived from the fimA gene, whereby the gene from isolates of D. nodosus that appeared to be glycosylated had potential glycosylation sites both inside and outside of the variable region of fimA. The results would also explain the observation that the calculated molecular weight of fimA from some D. nodosus serotypes does not correlate with the apparent size determined from electrophoretic mobility.