D R Scott

Summary

Affiliation: University of California
Country: USA

Publications

  1. pmc Cytoplasmic histidine kinase (HP0244)-regulated assembly of urease with UreI, a channel for urea and its metabolites, CO2, NH3, and NH4(+), is necessary for acid survival of Helicobacter pylori
    David R Scott
    Department of Physiology, David Geffen School of Medicine at UCLA, 405 Hilgard Ave, Los Angeles, California 90024, USA
    J Bacteriol 192:94-103. 2010
  2. pmc Helicobacter pylori impedes acid-induced tightening of gastric epithelial junctions
    Elizabeth A Marcus
    DGSOM at UCLA, VA GLAHS, 11301 Wilshire Blvd, Bldg 113, Rm 324, Los Angeles, CA 90073
    Am J Physiol Gastrointest Liver Physiol 305:G731-9. 2013
  3. pmc Expression of the Helicobacter pylori ureI gene is required for acidic pH activation of cytoplasmic urease
    D R Scott
    Department of Physiology, University of California at Los Angeles, Los Angeles, California
    Infect Immun 68:470-7. 2000
  4. pmc Gene expression in vivo shows that Helicobacter pylori colonizes an acidic niche on the gastric surface
    David R Scott
    Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90024, USA
    Proc Natl Acad Sci U S A 104:7235-40. 2007
  5. ncbi request reprint A H+-gated urea channel: the link between Helicobacter pylori urease and gastric colonization
    D L Weeks
    VA Greater Los Angeles Healthcare System and Department of Physiology, University of California, Los Angeles, CA 90073, USA
    Science 287:482-5. 2000
  6. pmc The periplasmic alpha-carbonic anhydrase activity of Helicobacter pylori is essential for acid acclimation
    Elizabeth A Marcus
    The Membrane Biology Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90073, USA
    J Bacteriol 187:729-38. 2005
  7. ncbi request reprint Review article: the control of gastric acid and Helicobacter pylori eradication
    G Sachs
    UCLA Digestive Research Center, Departments of Physiology and Medicine, University of California, Los Angeles, CA, USA
    Aliment Pharmacol Ther 14:1383-401. 2000
  8. ncbi request reprint Urea transport in bacteria: acid acclimation by gastric Helicobacter spp
    G Sachs
    Department of Physiology, Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90073, USA
    J Membr Biol 212:71-82. 2006
  9. pmc The effects of varying acidity on Helicobacter pylori growth and the bactericidal efficacy of ampicillin
    E A Marcus
    Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90073, USA
    Aliment Pharmacol Ther 36:972-9. 2012
  10. ncbi request reprint Mechanism of proton gating of a urea channel
    David L Weeks
    Department of Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073, USA
    J Biol Chem 279:9944-50. 2004

Collaborators

Detail Information

Publications29

  1. pmc Cytoplasmic histidine kinase (HP0244)-regulated assembly of urease with UreI, a channel for urea and its metabolites, CO2, NH3, and NH4(+), is necessary for acid survival of Helicobacter pylori
    David R Scott
    Department of Physiology, David Geffen School of Medicine at UCLA, 405 Hilgard Ave, Los Angeles, California 90024, USA
    J Bacteriol 192:94-103. 2010
    ..Assembly of a pH-regulatory complex of active urease with UreI provides an advantage for periplasmic buffering...
  2. pmc Helicobacter pylori impedes acid-induced tightening of gastric epithelial junctions
    Elizabeth A Marcus
    DGSOM at UCLA, VA GLAHS, 11301 Wilshire Blvd, Bldg 113, Rm 324, Los Angeles, CA 90073
    Am J Physiol Gastrointest Liver Physiol 305:G731-9. 2013
    ..H. pylori diminishes acid-induced tightening of cell junctions in a urease-dependent manner, suggesting that local pH elevation promotes barrier compromise and progression to mucosal damage...
  3. pmc Expression of the Helicobacter pylori ureI gene is required for acidic pH activation of cytoplasmic urease
    D R Scott
    Department of Physiology, University of California at Los Angeles, Los Angeles, California
    Infect Immun 68:470-7. 2000
    ..The ureI gene product is probably a pH activated urea transporter or perhaps regulates such a transporter as a function of periplasmic pH...
  4. pmc Gene expression in vivo shows that Helicobacter pylori colonizes an acidic niche on the gastric surface
    David R Scott
    Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90024, USA
    Proc Natl Acad Sci U S A 104:7235-40. 2007
    ..0. Hence, the pH of the habitat of H. pylori on the surface of the stomach largely determines the regulation of these specific groups of genes...
  5. ncbi request reprint A H+-gated urea channel: the link between Helicobacter pylori urease and gastric colonization
    D L Weeks
    VA Greater Los Angeles Healthcare System and Department of Physiology, University of California, Los Angeles, CA 90073, USA
    Science 287:482-5. 2000
    ..UreI functions as a H+-gated urea channel regulating cytoplasmic urease that is essential for gastric survival and colonization...
  6. pmc The periplasmic alpha-carbonic anhydrase activity of Helicobacter pylori is essential for acid acclimation
    Elizabeth A Marcus
    The Membrane Biology Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90073, USA
    J Bacteriol 187:729-38. 2005
    ..Hence, buffering of the periplasm to a pH consistent with viability depends not only on NH3 efflux from the cytoplasm but also on the conversion of CO2, produced by urease, to HCO3- by the periplasmic alpha-CA...
  7. ncbi request reprint Review article: the control of gastric acid and Helicobacter pylori eradication
    G Sachs
    UCLA Digestive Research Center, Departments of Physiology and Medicine, University of California, Los Angeles, CA, USA
    Aliment Pharmacol Ther 14:1383-401. 2000
    ..0, allowing acid resistance and growth at acidic pH in the presence of 1 mM urea. A hypothesis for the basis of combination therapy for eradication is also presented...
  8. ncbi request reprint Urea transport in bacteria: acid acclimation by gastric Helicobacter spp
    G Sachs
    Department of Physiology, Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90073, USA
    J Membr Biol 212:71-82. 2006
    ..The finding also of upregulation of the two-component histidine kinase HP0165 and its response element HP0166, illustrates the complexity of the acid acclimation processes involved in gastric colonization by this pathogen...
  9. pmc The effects of varying acidity on Helicobacter pylori growth and the bactericidal efficacy of ampicillin
    E A Marcus
    Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90073, USA
    Aliment Pharmacol Ther 36:972-9. 2012
    ..Identifying growth responses to varying medium pH may allow design of more effective treatment regimens...
  10. ncbi request reprint Mechanism of proton gating of a urea channel
    David L Weeks
    Department of Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073, USA
    J Biol Chem 279:9944-50. 2004
    ..Further studies on HhUreI may facilitate understanding of other physiologically important pH-responsive channels...
  11. pmc Acid-adaptive genes of Helicobacter pylori
    Yi Wen
    The Membrane Biology Laboratory, Department of Physiology and Medicine, University of California Los Angeles, 11301 Wilshire Boulevard, Los Angeles, CA 90073, USA
    Infect Immun 71:5921-39. 2003
    ..These results suggest that H. pylori has evolved multifaceted acid-adaptive mechanisms enabling it to colonize the stomach that may be novel targets for eliminating infection...
  12. pmc A cis-encoded antisense small RNA regulated by the HP0165-HP0166 two-component system controls expression of ureB in Helicobacter pylori
    Yi Wen
    The Membrane Biology Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, 11301 Wilshire Blvd, Bldg 113, Rm 324, Los Angeles, CA 90073, USA
    J Bacteriol 193:40-51. 2011
    ..The ability of the HP0165-HP0166 TCS to both increase and decrease ureB expression at low and high pHs, respectively, facilitates gastric habitation and colonization over the wide range of intragastric pHs experienced by the organism...
  13. ncbi request reprint Mechanisms of acid resistance due to the urease system of Helicobacter pylori
    David R Scott
    Department of Physiology, University of California Los Angeles, Los Angeles, California 90073, USA
    Gastroenterology 123:187-95. 2002
    ..Slower mechanisms may involve increased nickel insertion into apoenzyme, posttranscriptional regulation, or increased enzyme synthesis. The aim of this study was to further define regulation of urease under acidic conditions...
  14. pmc Involvement of the HP0165-HP0166 two-component system in expression of some acidic-pH-upregulated genes of Helicobacter pylori
    Yi Wen
    Membrane Biology Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, VA Greater Los Angeles Healthcare System, Los Angeles, California 90073, USA
    J Bacteriol 188:1750-61. 2006
    ..Regulation of these genes responds either to a decrease in the periplasmic pH alone (HP0165 dependent) or also to a decrease in the cytoplasmic pH (HP0165 independent)...
  15. ncbi request reprint Acid acclimation by Helicobacter pylori
    George Sachs
    Laboratory of Membrane Biology, David Geffen School of Medicine at the University of California Los Angeles, USA
    Physiology (Bethesda) 20:429-38. 2005
    ..1 in acidic media, whereas other neutralophiles cannot regulate periplasmic pH and thus only transit the stomach...
  16. pmc Gastric infection by Helicobacter pylori
    George Sachs
    Departments of Physiology and Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90024, USA
    Curr Gastroenterol Rep 11:455-61. 2009
    ..Continuing improvement of PPIs has led to the development of at least three candidate drugs with improved 24-hour acid control...
  17. ncbi request reprint The gastric biology of Helicobacter pylori
    George Sachs
    Department of Physiology, University of California, Los Angeles, California 90024, USA
    Annu Rev Physiol 65:349-69. 2003
    ..Understanding of these acid resistance and tolerance responses should provide novel eradication therapies for this carcinogenic gastric pathogen...
  18. pmc The HP0165-HP0166 two-component system (ArsRS) regulates acid-induced expression of HP1186 alpha-carbonic anhydrase in Helicobacter pylori by activating the pH-dependent promoter
    Yi Wen
    The Membrane Biology Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, USA
    J Bacteriol 189:2426-34. 2007
    ....
  19. pmc The pH-responsive regulon of HP0244 (FlgS), the cytoplasmic histidine kinase of Helicobacter pylori
    Yi Wen
    The Membrane Biology Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, California 90073, USA
    J Bacteriol 191:449-60. 2009
    ....
  20. ncbi request reprint Cell lysis is responsible for the appearance of extracellular urease in Helicobacter pylori
    E A Marcus
    Department of Physiology, University of California, Los Angeles and VA Greater Los Angeles Health Care System, Los Angeles, CA 90073, USA
    Helicobacter 6:93-9. 2001
    ..pylori...
  21. pmc Genes of Helicobacter pylori regulated by attachment to AGS cells
    Nayoung Kim
    Department of Physiology and Medicine, Geffen School of Medicine, UCLA and VA Greater Los Angeles Health Care System, Los Angeles, California 90073, USA
    Infect Immun 72:2358-68. 2004
    ..The alteration of gene expression in H. pylori after adhesion to gastric cells in vitro suggests that changes in motility, outer membrane composition, and stress responses, among other changes, may be involved in gastric colonization...
  22. pmc Colloidal bismuth subcitrate impedes proton entry into Helicobacter pylori and increases the efficacy of growth-dependent antibiotics
    E A Marcus
    Department of Pediatrics, DGSOM at UCLA, Los Angeles, CA, USA
    Aliment Pharmacol Ther 42:922-33. 2015
    ..Helicobacter pylori is a neutralophile adapted to survive the acidic gastric environment via acid acclimation, but demonstrates more robust growth at neutral pH. Many antibiotics used to treat H. pylori rely on bacterial growth...
  23. pmc The binding selectivity of vonoprazan (TAK-438) to the gastric H+, K+ -ATPase
    D R Scott
    Department of Physiology, DGSOM at UCLA, Los Angeles, CA, USA
    Aliment Pharmacol Ther 42:1315-26. 2015
    ..In contrast to other PCABs, vonoprazan has a long duration of action, resulting in 24-h control of acid secretion, a high pKa of 9.37 and high affinity (Ki = 3.0 ηmol/L)...
  24. pmc Improved amplification of genital human papillomaviruses
    P E Gravitt
    Department of Human Genetics, Roche Molecular Systems, Alameda, California, USA
    J Clin Microbiol 38:357-61. 2000
    ..This new primer system will be useful in assessing the natural history of HPV infections, particularly when the analysis requires HPV typing...
  25. ncbi request reprint Current trends in the treatment of upper gastrointestinal disease
    George Sachs
    Geffen School of Medicine at UCLA and GWLA Health Center, Los Angeles, USA
    Best Pract Res Clin Gastroenterol 16:835-49. 2002
    ..Research continues in an attempt to find improved means of acid control and better methods for the eradication of H. pylori based on unique proteins expressed by the organism to resist gastric acidity...
  26. pmc Proteins released by Helicobacter pylori in vitro
    Nayoung Kim
    Department of Physiology and Medicine, UCLA Digestive Research Center, University of California, Los Angeles, and VA Greater Los Angeles Health Care System, 90073, USA
    J Bacteriol 184:6155-62. 2002
    ..These proteins may be implicated in H. pylori-induced effects on the gastric epithelium...
  27. ncbi request reprint Medium pH-dependent redistribution of the urease of Helicobacter pylori
    Wu Hong
    Department of Microbiology, Osaka Medical College, 2 7 Daigaku machi, Takatsuki shi, Osaka 569 8686, Japan
    J Med Microbiol 52:211-6. 2003
    ..This is the first report of the intracellular transport of molecules in bacteria in response to changes in the extracellular environment...
  28. ncbi request reprint Human papillomavirus prevalence in women who have and have not undergone hysterectomies
    Philip E Castle
    Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, MD, USA
    J Infect Dis 194:1702-5. 2006
    ..5% for WH) between the 2 groups of women. Although WH have a similar prevalence of carcinogenic HPV infection, compared with WNH without a cervix, they have minimal risk of HPV-induced cancer and are unlikely to benefit from HPV testing...
  29. ncbi request reprint Use of human papillomavirus DNA testing to compare equivocal cervical cytologic interpretations in the United States, Scandinavia, and the United Kingdom
    David R Scott
    Kaiser Permanente Department of Pathology, Portland, Oregon, USA
    Cancer 96:14-20. 2002
    ..Because international differences may be particularly marked, international comparisons of emerging data will require clear translations of "equivocal" and similar terms...