background   and   objectives:    the   toxin   co-regulated   pilus   a   (tcpa)   has   been   described   as   a   criti- cal  pathogenicity  factor  of   vibrio  cholerae .  tcpa  is  a  candidate  for  making  subunit  vaccine  against  chol- era.  the  aim  of  this  study  was  to  produce  a  candidate  vaccine  by  expressing  recombinant  tcpa  in   e.  coli . materials and methods: i...

The Streptococcus pneumoniae pilus-1 is encoded by pilus islet 1 (PI-1), which has three clonal variants (clade I, II and III) and is present in about 30% of clinical pneumococcal isolates. In vitro and in vivo assays have demonstrated that pilus-1 is involved in attachment to epithelial cells and virulence, as well as protection in mouse models of infection. Several reports suggest that pilus-...

Expression of the pneumococcal type 1 pilus is bistable and positively regulated by the transcription factor RlrA. RlrA is also known to positively control its own expression. Here we present evidence that bistable expression of the type 1 pilus is mediated by the positive-feedback loop controlling rlrA expression.

The virulence of the opportunistic pathogen Pseudomonas aeruginosa involves the coordinate expression of many virulence factors, including type IV pili, which are required for colonization of host tissues and for twitching motility. Type IV pilus function is controlled in part by the Chp chemosensory system, which includes a histidine kinase, ChpA, and two CheY-like response regulators, PilG an...

UNLABELLED The pneumococcal Pilus-1 enhances attachment to epithelial cells in the respiratory tract and subsequent invasion. Pilus-1 expression is bi-stable and positively regulated by the RlrA transcriptional regulator. To delineate the role of pilus-1 in Experimental Otitis Media (EOM), we evaluated colonization and disease due to a Streptococcus pneumoniae (SP) wild type strain (Taiwan19F-1...

The Neisseria gonorrhoeae type IV pilus is a retractile appendage that can generate forces near 100 pN. We tested the hypothesis that type IV pilus retraction influences epithelial cell gene expression by exerting tension on the host membrane. Wild-type and retraction-defective bacteria altered the expression of an identical set of epithelial cell genes during attachment. Interestingly, pilus r...

Chitin, an insoluble polymer of GlcNAc, is an abundant source of carbon, nitrogen, and energy for marine microorganisms. Microarray expression profiling and mutational studies of Vibrio cholerae growing on a natural chitin surface, or with the soluble chitin oligosaccharides (GlcNAc)(2-6), GlcNAc, or the glucosamine dimer (GlcN)2 identified three sets of differentially regulated genes. We show ...

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...

conclusions our results indicated that the dissemination of pi-1 was widespread in s. pneumoniae isolates, although no pi-2 isolates were detected. furthermore, the frequency of rlra and rrgc of clinical isolates was significantly more than that of normal flora isolates. results the results confirmed the presence of rlra and rrgc genes in both clinical (n = 39) and normal flora (n = 26) isolate...

Bdellovibrio bacteriovorus is a δ-proteobacterium that preys upon Salmonella spp., E. coli, and other Gram-negative bacteria. Bdellovibrio can grow axenically (host-independent, HI, rare and mutation-driven) or subsist via a predatory lifecycle (host-dependent, HD, the usual case). Upon contact with prey, B. bacteriovorus enters the host periplasm from where it slowly drains the host cytosol of...