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J, Draper K, Karplus Karen Ottemann
Published in
Journal of Bacteriology
We report the identification and characterization of a previously unidentified protein domain found in bacterial chemoreceptors and other bacterial signal transduction proteins. This domain contains a motif of three noncontiguous histidines and one cysteine, arranged as Hxx[WFYL]x(21-28)Cx[LFMVI]Gx[WFLVI]x(18-27)HxxxH(boldface type indicates residu...
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Dj, Mcgee Ml, Langford El, Watson Je, Carter Yt, Chen Karen Ottemann
Published in
Infection and Immunity
Helicobacter pylori causes disease in the human stomach and in mouse and gerbil stomach models. Previous results have shown that motility is critical for H. pylori to colonize mice, gerbils, and other animal models. The role of chemotaxis, however, in colonization and disease is less well understood. Two genes in the H. pylori chemotaxis pathway, c...
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P, Lertsethtakarn Karen Ottemann
Published in
Molecular Microbiology
Aspartyl-phosphate phosphatases underlie the rapid responses of bacterial chemotaxis. One such phosphatase, CheZ, was originally proposed to be restricted to beta and gamma proteobacter, suggesting only a small subset of microbes relied on this protein. A putative CheZ phosphatase was identified genetically in the epsilon proteobacter Helicobacter ...
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Tm, Andermann Yt, Chen Karen Ottemann
Published in
Infection and Immunity
Helicobacter pylori must be motile or display chemotaxis to be able to fully infect mammals, but it is not known how this chemotaxis is directed. We disrupted two genes encoding predicted chemoreceptors, tlpA and tlpC. H. pylori mutants lacking either of these genes are fully motile and chemotactic in vitro and are as able as the wild type to infec...
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Da, Baltrus Mr, Amieva A, Covacci Tm, Lowe Ds, Merrell Karen Ottemann M, Stein Nr, Salama K, Guillemin
Published in
Journal of Bacteriology
Helicobacter pylori is a gram-negative pathogen that colonizes the stomachs of over half the world s population and causes a spectrum of gastric diseases including gastritis, ulcers, and gastric carcinoma. The H. pylori species exhibits unusually high levels of genetic variation between strains. Here we announce the complete genome sequence of H. p...
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Pj, Schatz Kl, Bieker Karen Ottemann Tj, Silhavy J, Beckwith
Published in
The EMBO Journal
The E. coli secE (prlG) gene codes for an integral cytoplasmic membrane protein which is part of the cell s secretory machinery. A deletion of nearly the entire gene renders the cell dependent on the presence of a complementing secE+ plasmid, indicating that the SecE protein is essential for growth. Deletions which remove carboxy-terminal sequences...
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Ma, Schumacher R, Feng E, Aihara Ac, Engevik Mh, Montrose Karen Ottemann Y, Zavros
Published in
Helicobacter
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K, Terry Sm, Williams L, Connolly Karen Ottemann
Published in
Infection and Immunity
Helicobacter pylori is a human gastric pathogen associated with gastric and duodenal ulcers as well as specific gastric cancers. H. pylori infects approximately 50% of the world s population, and infections can persist throughout the lifetime of the host. Motility and chemotaxis have been shown to be important in the infection process of H. pylori....
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As, Rolig Je, Carter Karen Ottemann
Published in
Proceedings of the National Academy of Sciences
The host inflammatory response to chronic bacterial infections often dictates the disease outcome. In the case of the gastric pathogen Helicobacter pylori, host inflammatory responses result in outcomes that range from moderate and asymptomatic to more severe with concomitant ulcer or cancers. It was found recently that H. pylori chemotaxis mutants...
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Karen Ottemann Jj, Mekalanos
Published in
Molecular Microbiology
The ToxR protein is a transmembrane protein that regulates the expression of several virulence factors of Vibrio cholerae. Previous analysis of fusion proteins between ToxR and alkaline phosphatase (ToxR-PhoA) suggested that ToxR was active as a dimer. In order to determine whether dimerization of the ToxR periplasmic domain was essential for activ...
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Ma, Schumacher E, Aihara R, Feng A, Engevik Nf, Shroyer Karen Ottemann Rt, Worrell Mh, Montrose Ra, Shivdasani Y, Zavros
...
Published in
The Journal of Physiology
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As, Rolig C, Cech E, Ahler Je, Carter Karen Ottemann
Published in
Infection and Immunity
Helicobacter pylori infects over 3 billion people worldwide and is the primary risk factor for gastric cancer. Most individuals infected with H. pylori develop only asymptomatic gastritis; however, some develop ulcers or gastric adenocarcinoma. We demonstrate that one previously unappreciated parameter influencing H. pylori disease outcome is varia...
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D, Keilberg Karen Ottemann
Published in
Environmental Microbiology
Helicobacter pylori is a human-specific pathogen that chronically infects about 50% of the world s population. After travelling through the harsh environment of the stomach lumen, H. pylori colonizes the mucosal surface and within the glands of the human stomach. During colonization, H. pylori uses motility and its chemotaxis signalling system to s...
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Lh, Ta Lm, Hansen We, Sause O, Shiva A, Millstein Karen Ottemann Ar, Castillo Jv, Solnick
Published in
Frontiers in Cellular and Infection Microbiology
The Helicobacter pyloricag pathogenicity island (cag PAI) encodes a type IV secretion system that is more commonly found in strains isolated from patients with gastroduodenal disease than from those with asymptomatic gastritis. Genome-wide organization of the transcriptional units in H. pylori strain 26695 was recently established using RNA sequenc...
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L, Sanders Tm, Andermann Karen Ottemann
Published in
Microbiology
Directed motility, or chemotaxis, is required for Helicobacter pylori to establish infection in the stomach, although the full repertoire of this bacterium s chemotactic responses is not yet known. Here we report that H. pylori responds to zinc as an attractant and nickel as a repellent. To reach this conclusion, we employed both a temporal chemota...
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Karen Ottemann Ac, Lowenthal
Published in
Infection and Immunity
Helicobacter pylori has been shown to require flagella for infection of the stomach. To analyze whether flagella themselves or motility is needed by these pathogens, we constructed flagellated nonmotile mutants. This was accomplished by using both an insertion mutant and an in-frame deletion of the motB gene. In vitro, these mutants retain flagella...
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Karen Ottemann W, Xiao Yk, Shin Jr, Koshland De
Published in
Science
To characterize the mechanism by which receptors propagate conformational changes across membranes, nitroxide spin labels were attached at strategic positions in the bacterial aspartate receptor. By collecting the electron paramagnetic resonance spectra of these labeled receptors in the presence and absence of the ligand aspartate, ligand binding w...
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Tm, Andermann Yt, Chen Karen Ottemann
Published in
Infection and Immunity
Helicobacter pylori must be motile or display chemotaxis to be able to fully infect mammals, but it is not known how this chemotaxis is directed. We disrupted two genes encoding predicted chemoreceptors, tlpA and tlpC. H. pylori mutants lacking either of these genes are fully motile and chemotactic in vitro and are as able as the wild type to infec...
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Ar, Castillo Aj, Woodruff Le, Connolly We, Sause Karen Ottemann
Published in
Infection and Immunity
Here we undertook to identify colonization and gastric disease-promoting factors of the human gastric pathogen Helicobacter pylori as genes that were induced in response to the stomach environment. Using recombination-based in vivo expression technology (RIVET), we identified six promoters induced in the host compared to laboratory conditions. Thre...
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Karen Ottemann Jr, Koshland De
Published in
Proceedings of the National Academy of Sciences
The bacterial aspartate receptor was reconstructed to eliminate the transmembrane domain, thus connecting the recognition domain directly to the effector domain. The resulting soluble receptor folded correctly and was no longer an integral membrane protein. Upon aspartate binding, this soluble receptor was stabilized to a similar extent as that of ...
