The secreton or type II secretion machinery of gram-negative bacteria includes several type IV pilin-like proteins (the pseudopilins) that are absolutely required for secretion. We previously reported the presence of a bundled pilus composed of the pseudopilin PulG on the surface of agar-grown Escherichia coli K-12 cells expressing the Klebsiella oxytoca pullulanase (Pul) secreton genes at high...

Ultrastructural studies of Aeromonas hydrophila strain AH26 revealed two distinctive pilus types: "straight" pili appear as brittle, rod-like filaments, whereas "flexible" pili are supple and curvilinear. Straight pili are produced constitutively under all tested conditions of growth. In contrast, the expression of flexible pili is regulated by physical and chemical variables, being produced at...

UNLABELLED Uropathogenic Escherichia coli (UPEC) is the primary cause of community-acquired urinary tract infections (UTIs). UPEC bind the bladder using type 1 pili, encoded by the fim operon in nearly all E. coli. Assembled type 1 pili terminate in the FimH adhesin, which specifically binds to mannosylated glycoproteins on the bladder epithelium. Expression of type 1 pili is regulated in part ...

The reactivity of anti-pilus antibodies to native and denatured Haemophilus influenzae b (Hib) pili was studied using rabbit serum prepared against piliated H. influenzae b strain M43 (p+) and adsorbed with its non-piliated variant, strain M42 (p-). The specificity of the adsorbed serum for Hib pili was documented by immunogold electron microscopy and by immunoprecipitation, which revealed the ...

The in situ stimulation of Fe(III) oxide reduction by Geobacter bacteria leads to the concomitant precipitation of hexavalent uranium [U(VI)] from groundwater. Despite its promise for the bioremediation of uranium contaminants, the biological mechanism behind this reaction remains elusive. Because Fe(III) oxide reduction requires the expression of Geobacter's conductive pili, we evaluated their...

N-Glycosylation is a post-translational modification common to all three domains of life. In many archaea, the oligosacharyltransferase (AglB)-dependent N-glycosylation of flagellins is required for flagella assembly. However, whether N-glycosylation is required for the assembly and/or function of the structurally related archaeal type IV pili is unknown. Here, we show that of six Haloferax vol...

The hair follicle is a complete mini-organ that lends itself as a model for investigation of a variety of complex biological phenomena, including stem cell biology, organ regeneration and cloning.  The arrector pili muscle inserts into the hair follicle at the level of the bulge- the epithelial stem cell niche.  The arrector pili muscle has been previously thought to be merely a bystander and n...

We have demonstrated binding of purified pili from a strain of Escherichia coli to Vero cell monolayers as a model of prokaryotic-eukaryotic cell adherence. Pili bound to the tissue culture in a rapid reaction that did not require enzymatic activation. Attachment occurred optimally at pH 4-5 and could be inhibited by analogues of D-mannose, anti-pili antibodies, or by preincubation of tissue ce...

Pili of pathogenic Neisseria are major virulence factors associated with adhesion, twitching motility, auto-aggregation, and DNA transformation. Pili of N. meningitidis are subject to several different post-translational modifications. Among these pilin modifications, the presence of phosphorylcholine (ChoP) and a glycan on the pilin protein are phase-variable (subject to high frequency, revers...

Extracellular non-flagellar appendages, called pili or fimbriae, are widespread in gram-negative bacteria. They are involved in many different functions, including motility, adhesion, biofilm formation, and uptake of DNA. Sequencing data for a large number of cyanobacterial genomes revealed that most of them contain genes for pili synthesis. However, only for a very few cyanobacteria structure ...