Legionella pneumophila, the causative agent of Legionnaires' Disease, is a gram-negative bacterium that evades delivery to the lysosomes of alveolar macrophages by arresting phagosome maturation. We can use this intracellular pathogen as a tool to study critical functions of macrophages, such as endosomal/lysosomal trafficking. L. pneumophila can facilitate inhibition of phagosome maturation by modifications of its surface properties expressed during the post-exponential (PE) phase of growth. Analogous to the developmentally regulated lipophosphoglycan of Leishmania spp. which blocks phagosome maturation, we hypothesize that L. pneumophila expresses a regulated surface glycoconjugate, likely lipopolysaccharide (LPS). Our objective is to identify the glycoconjugates that are modified during the transition to L. pneumophila's virulent phase and their specific roles in phagosome maturation.
Specific aim 1 is to screen an established mutant library for their crystal violet binding properties and isolate those mutants which abnormally bind crystal violet in the PE phase, thus indicating abnormal surface properties.
Specific aim 2 is to construct mutants of the genes encoding LPS biosynthetic genes to determine if these genes are required to block phagosome maturation.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
5F31AI061835-03
Application #
7115735
Study Section
Special Emphasis Panel (ZRG1-ONC-O (29))
Program Officer
Hernandez, Milton J
Project Start
2004-09-01
Project End
2008-08-31
Budget Start
2006-09-01
Budget End
2007-08-31
Support Year
3
Fiscal Year
2006
Total Cost
$35,754
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Whitfield, Natalie N; Byrne, Brenda G; Swanson, Michele S (2010) Mouse macrophages are permissive to motile Legionella species that fail to trigger pyroptosis. Infect Immun 78:423-32