Distinct cytoskeletal proteins define zones of enhanced cell wall synthesis in .

Helical cell shape is necessary for efficient stomach colonization by , but the molecular mechanisms for generating helical shape remain unclear. The helical centerline pitch and radius of wild-type cells dictate surface curvatures of considerably higher positive and negative Gaussian curvatures than those present in straight- or curved-rod . Quantitative 3D microscopy analysis of short pulses with either -acetylmuramic acid or D-alanine metabolic probes showed that cell wall growth is enhanced at both sidewall curvature extremes.

A Genome-Wide Helicobacter pylori Morphology Screen Uncovers a Membrane-Spanning Helical Cell Shape Complex.

Evident in its name, the gastric pathogen has a helical cell morphology which facilitates efficient colonization of the human stomach. An improved light-focusing strategy allowed us to robustly distinguish even subtle perturbations of cell morphology by deviations in light-scattering properties measured by flow cytometry. Profiling of an arrayed genome-wide deletion library identified 28 genes that influence different aspects of cell shape, including properties of the helix, cell length or width, cell filament formation, cell shape heterogeneity, and cell branching.

The Helicobacter pylori cell shape promoting protein Csd5 interacts with the cell wall, MurF, and the bacterial cytoskeleton.

Chronic infection with Helicobacter pylori can lead to the development of gastric ulcers and stomach cancers. The helical cell shape of H. pylori promotes stomach colonization.

Staying in Shape: the Impact of Cell Shape on Bacterial Survival in Diverse Environments.

Bacteria display an abundance of cellular forms and can change shape during their life cycle. Many plausible models regarding the functional significance of cell morphology have emerged. A greater understanding of the genetic programs underpinning morphological variation in diverse bacterial groups, combined with assays of bacteria under conditions that mimic their varied natural environments, from flowing freshwater streams to diverse human body sites, provides new opportunities to probe the functional significance of cell shape.

A Bacterial Cell Shape-Determining Inhibitor.

Helicobacter pylori and Campylobacter jejuni are human pathogens and causative agents of gastric ulcers/cancer and gastroenteritis, respectively. Recent studies have uncovered a series of proteases that are responsible for maintaining the helical shape of these organisms. The H.

Dermatophytes activate skin keratinocytes via mitogen-activated protein kinase signaling and induce immune responses.

Dermatophytes cause superficial and cutaneous fungal infections in immunocompetent hosts and invasive disease in immunocompromised hosts. However, the host mechanisms that regulate innate immune responses against these fungi are largely unknown. Here, we utilized commercially available epidermal tissues and primary keratinocytes to assess (i) damage induction by anthropophilic, geophilic, and zoophilic dermatophyte strains and (ii) the keratinocyte signaling pathways, transcription factors, and proinflammatory responses induced by a representative dermatophyte, Trichophyton equinum.

Helical shape of Helicobacter pylori requires an atypical glutamine as a zinc ligand in the carboxypeptidase Csd4.

Peptidoglycan modifying carboxypeptidases (CPs) are important determinants of bacterial cell shape. Here, we report crystal structures of Csd4, a three-domain protein from the human gastric pathogen Helicobacter pylori. The catalytic zinc in Csd4 is coordinated by a rare His-Glu-Gln configuration that is conserved among most Csd4 homologs, which form a distinct subfamily of CPs.

Plasmid-encoded ComI inhibits competence in the ancestral 3610 strain of Bacillus subtilis.

Natural competence is a process by which bacteria construct a membrane-associated machine for the uptake and integration of exogenous DNA. Many bacteria harbor genes for the DNA uptake machinery and yet are recalcitrant to DNA uptake for unknown reasons. For example, domesticated laboratory strains of Bacillus subtilis are renowned for high-frequency natural transformation, but the ancestral B.

Modified mariner transposons for random inducible-expression insertions and transcriptional reporter fusion insertions in Bacillus subtilis.

Transposons are mobile genetic elements bounded by insertion sequences that are recognized by a specific mobilizing transposase enzyme. The transposase may mobilize not only the insertion sequences but also intervening DNA. mariner is a particularly efficient transposon for the random chromosomal integration of genes and insertional mutagenesis.

The EpsE flagellar clutch is bifunctional and synergizes with EPS biosynthesis to promote Bacillus subtilis biofilm formation.

Many bacteria inhibit motility concomitant with the synthesis of an extracellular polysaccharide matrix and the formation of biofilm aggregates. In Bacillus subtilis biofilms, motility is inhibited by EpsE, which acts as a clutch on the flagella rotor to inhibit motility, and which is encoded within the 15 gene eps operon required for EPS production. EpsE shows sequence similarity to the glycosyltransferase family of enzymes, and we demonstrate that the conserved active site motif is required for EPS biosynthesis.

Role of the sigmaD-dependent autolysins in Bacillus subtilis population heterogeneity.

Exponentially growing populations of Bacillus subtilis contain two morphologically and functionally distinct cell types: motile individuals and nonmotile multicellular chains. Motility differentiation arises because RNA polymerase and the alternative sigma factor sigma(D) activate expression of flagellin in a subpopulation of cells. Here we demonstrate that the peptidoglycan-remodeling autolysins under sigma(D) control, LytC, LytD, and LytF, are expressed in the same subpopulation of cells that complete flagellar synthesis.

RemA (YlzA) and RemB (YaaB) regulate extracellular matrix operon expression and biofilm formation in Bacillus subtilis.

Biofilms are multicellular aggregates stabilized by an extracellular matrix. In Bacillus subtilis, the biofilm matrix is composed of an extracellular polysaccharide and the secreted protein TasA. Expression of both of the matrix components is repressed by the DNA-binding master regulator, SinR.

A molecular clutch disables flagella in the Bacillus subtilis biofilm.

Biofilms are multicellular aggregates of sessile bacteria encased by an extracellular matrix and are important medically as a source of drug-resistant microbes. In Bacillus subtilis, we found that an operon required for biofilm matrix biosynthesis also encoded an inhibitor of motility, EpsE. EpsE arrested flagellar rotation in a manner similar to that of a clutch, by disengaging motor force-generating elements in cells embedded in the biofilm matrix.