The order Heterocorallia is an enigmatic, anatomically distinct group of calcifying Palaeozoic corals with unclear affinities to other, either extinct or modern cnidarian lineages. Here, we present results microstructure and stable isotope studies on exceptionally well-preserved skeletons two species the heterocoral Oligophylloides from Famennian (Upper Devonian) Anti-Atlas, Morocco Holy Cross ...

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...

The rugose colonial variant of Vibrio cholerae O1 El Tor produces an exopolysaccharide (EPS) that enables the organism to form a biofilm and to resist oxidative stress and the bactericidal action of chlorine. Transposon mutagenesis of the rugose variant led to the identification of vpsR, which codes for a homologue of the NtrC subclass of response regulators. Targeted disruption of vpsR in the ...

The rugose colonial variant of Vibrio cholerae O1 El Tor produces an exopolysaccharide (EPS(ETr)) that enables the organism to form a biofilm and to resist oxidative stress and the bactericidal action of chlorine. Transposon mutagenesis of the rugose variant led to the identification of vpsR, which codes for a homologue of the NtrC subclass of response regulators. Targeted disruption of vpsR in...

Phase variation between smooth and rugose colony variants of Vibrio cholerae is predicted to be important for the pathogen's survival in its natural aquatic ecosystems. The rugose variant forms corrugated colonies, exhibits increased levels of resistance to osmotic, acid, and oxidative stresses, and has an enhanced capacity to form biofilms. Many of these phenotypes are mediated in part by incr...

The Bitlis-Pötürge Massif of SE Turkey is a metamorphic belt separating the Arabian Plate from Taurides. It includes non-metamorphic Palaeozoic sequence that contains locally fossiliferous strata. Here reported for first time an assemblage Upper Devonian rugose and tabulate corals Meydan Formation, composed Frechastraea schafferi (PENECKE), Peneckiella cf. teicherti HILL, Pseudopexiphyllum supr...