Bacterial biofilm formation is a complex developmental process involving cellular differentiation and the formation of intricate 3D structures. Here we demonstrate that exposure to ferric chloride triggers rugose biofilm formation by the uropathogenic Escherichia coli strain UTI89 and by enteric bacteria Citrobacter koseri and Salmonella enterica serovar typhimurium. Two unique and separable ce...

In October, 2010, epidemic cholera was reported for the first time in Haiti in over 100 years. Establishment of cholera endemicity in Haiti will be dependent in large part on the continued presence of toxigenic V. cholerae O1 in aquatic reservoirs. The rugose phenotype of V. cholerae, characterized by exopolysaccharide production that confers resistance to environmental stress, is a potential c...

Rugose phenotypes, such as those observed in Vibrio cholerae, have increased resistance to chlorine, oxidative stress, and complement-mediated killing. In this study we identified and defined a rugose phenotype in Salmonella enterica serovar Typhimurium DT104 and showed induction only on certain media at 25 degrees C after 3 days of incubation. Incubation at 37 degrees C resulted in the appeara...

Vibrio cholerae O1 strain TSI-4 (El Tor, Ogawa) can shift to a rugose colony morphology from its normal translucent colony morphology in response to nutrient starvation. We have investigated differences between the rugose and translucent forms of V. cholerae O1 strain TSI-4. Electron microscopic examination of the rugose form of TSI-4 (TSI-4/R) revealed thick, electron-dense exopolysaccharide m...

Vibrio cholerae can switch to a 'rugose' phenotype characterized by an exopolysaccharide (EPS) matrix, wrinkled colony morphology, increased biofilm formation and increased survival under specific conditions. The vps gene cluster responsible for the biosynthesis of the rugose EPS (rEPS) is positively regulated by VpsR. We recently identified media (APW#3) promoting EPS production and the rugose...

We report a previously undescribed mechanism for the rugose morphotype in Shewanella oneidensis, a research model for investigating redox transformations of environmental contaminants. Bacteria may form smooth or rugose colonies on agar plates. In general, conversion from the smooth to rugose colony morphotype is attributed to increased production of exopolysaccharide (EPS). In this work, we di...

We study the ow of a uid occupying an innnite horizontal domain bounded by a rugose plate which is at rest and by a plane plate which moves with a constant velocity. The rugose plate is covered with periodically distibuted asperities of size ". We prove that, outside a neighbourhood of the rugose region, the ow behaves asymptotically as a Couette ow, as " ! 0, up to an exponentially small error...

Vibrio cholerae can shift to a rugose colony phenotype, reflecting expression of an exopolysaccharide that provides protection against a variety of environmental stresses. Our data indicate that expression of the rugose phenotype is inhibited by a variety of sugars, including sucrose, dextrose, arabinose, fructose, and maltose. Inhibition by sucrose may be one factor in explaining the failure o...

Vibrio cholerae, the causative agent of cholera, can undergo phenotypic variation generating rugose and smooth variants. The rugose variant forms corrugated colonies and well-developed biofilms and exhibits increased levels of resistance to several environmental stresses. Many of these phenotypes are mediated in part by increased expression of the vps genes, which are organized into vps-I and v...

In the developing Drosophila eye, cell fate determination and pattern formation are directed by cell-cell interactions mediated by signal transduction cascades. Mutations at the rugose locus (rg) result in a rough eye phenotype due to a disorganized retina and aberrant cone cell differentiation, which leads to reduction or complete loss of cone cells. The cone cell phenotype is sensitive to the...