The goal of this research is to understand the mechanism by which the bubonic plague bacterium, Yersinia pestis, colonizes its vector, the flea. This proposal describes an experimental system in which the nematode Caenorhabditis elegans is a surrogate for the flea, which allows use of powerful model organism genetic methods. Y. pestis colonizes the flea digestive tract and physically blocks the insect from feeding, leading to transmission of plague to new hosts through flea bites. This process requires the bacterial genes known as hms. Y. pestis creates a visible biofilm on the surface of C. elegans, which also requires hms genes. The biofilm blocks feeding of the nematodes and impairs their growth, a physical effect similar to the feeding blockage that occurs in the digestive tracts of infected fleas. These observations suggest that Y. pestis blocks fleas with a biofilm. The nematode will be used to further understand this process in an easily manipulated laboratory system, and the results can then be investigated directly in flea-bacteria interactions. The impact on human health of these studies will be: 1) Identification and characterization, in bacteria or flea or both, of molecular targets for drugs that could reduce or eliminate plague in rodent flea populations and be used in response to bioweapon attacks with plague-carrying fleas. 2) Deeper understanding of how biofilms attach to living tissues, a process important in a wide variety of infectious diseases. 3) Identification of nematode surface components, with potential for translation to treatment of helminthic infections.
The specific aims of this proposal are: 1) Determine the roles in biofilm formation of hms and other Yersinia genes. 2) Determine the polysaccharide content and structure of the biofilm and develop reagents for its detection. 3) Clone three C. elegans gene involved in biofilm adherence and determine the localization in the worm of the encoded proteins.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI057512-04
Application #
7251512
Study Section
Special Emphasis Panel (ZRG1-IDM-A (90))
Program Officer
Mukhopadhyay, Suman
Project Start
2004-07-01
Project End
2009-06-30
Budget Start
2007-07-01
Budget End
2008-06-30
Support Year
4
Fiscal Year
2007
Total Cost
$292,039
Indirect Cost
Name
University of California San Francisco
Department
Anatomy/Cell Biology
Type
Schools of Dentistry
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Sun, Yi-Cheng; Guo, Xiao-Peng; Hinnebusch, B Joseph et al. (2012) The Yersinia pestis Rcs phosphorelay inhibits biofilm formation by repressing transcription of the diguanylate cyclase gene hmsT. J Bacteriol 194:2020-6
Sun, Yi-Cheng; Koumoutsi, Alexandra; Jarrett, Clayton et al. (2011) Differential control of Yersinia pestis biofilm formation in vitro and in the flea vector by two c-di-GMP diguanylate cyclases. PLoS One 6:e19267
Drace, Kevin; McLaughlin, Stephanie; Darby, Creg (2009) Caenorhabditis elegans BAH-1 is a DUF23 protein expressed in seam cells and required for microbial biofilm binding to the cuticle. PLoS One 4:e6741
Sun, Yi-Cheng; Koumoutsi, Alexandra; Darby, Creg (2009) The response regulator PhoP negatively regulates Yersinia pseudotuberculosis and Yersinia pestis biofilms. FEMS Microbiol Lett 290:85-90
Drace, Kevin; Darby, Creg (2008) The hmsHFRS operon of Xenorhabdus nematophila is required for biofilm attachment to Caenorhabditis elegans. Appl Environ Microbiol 74:4509-15
Sun, Yi-Cheng; Hinnebusch, B Joseph; Darby, Creg (2008) Experimental evidence for negative selection in the evolution of a Yersinia pestis pseudogene. Proc Natl Acad Sci U S A 105:8097-101
Darby, Creg (2008) Uniquely insidious: Yersinia pestis biofilms. Trends Microbiol 16:158-64
Darby, Creg; Chakraborti, Amrita; Politz, Samuel M et al. (2007) Caenorhabditis elegans mutants resistant to attachment of Yersinia biofilms. Genetics 176:221-30
Tan, Li; Darby, Creg (2006) Yersinia pestis YrbH is a multifunctional protein required for both 3-deoxy-D-manno-oct-2-ulosonic acid biosynthesis and biofilm formation. Mol Microbiol 61:861-70
Darby, Creg; Ananth, Sandya L; Tan, Li et al. (2005) Identification of gmhA, a Yersinia pestis gene required for flea blockage, by using a Caenorhabditis elegans biofilm system. Infect Immun 73:7236-42

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