Gene conversion appears to be the frequent mechanism in Neisseria gonorrhoeae that leads to an altered expression of pilin, the subunit component of the pili. In this process segments of variable sequence information, the minicassettes, are transferred from silent storage loci into an expression locus. As a putative consequence of the rearrangement in the pilE gene, gonococci can enter a differ...

Type IV pili are important for microcolony formation, biofilm formation, twitching motility, and attachment. We and others have shown that type IV pili are important for protein secretion across the outer membrane, similar to type II secretion systems. This study explored the relationship between protein secretion and pilus formation in Vibrio cholerae. The toxin-coregulated pilus (TCP), a type...

Vibrio vulnificus expresses a multitude of cell-associated and secreted factors that potentially contribute to pathogenicity, although the specific roles of most of these factors have been difficult to define. Previously we have shown that a mutation in pilD (originally designated vvpD), which encodes a type IV prepilin peptidase/N-methyltransferase, abolishes expression of surface pili, sugges...

The pili of the stalked bacterium Caulobacter crescentus are assembled at a specific time in the life cycle at one pole of the cell and are composed of the monomer protein, pilin. A previous study demonstrated that the onset of pilin synthesis occurs well before pili appear on the surface, suggesting that pilin accumulates within the cell. In the present study, an electron microscope immunocyto...

The attachment of gonococci to mucosal surfaces is of primary importance in their interactions with the genito-urinary tract of the human host. This process may be, in part, mediated by pili, which are proteinaceous appendages emanating from the bacterial cell surface. Observations by Kellogg et al. (1) suggested that certain colonial morphological phenotypes are associated with virulence. Subs...