Infectious diseases continue to be a significant cause of morbidity and mortality in both the United States and the rest of the world. This situation is made even more complicated by the continuing emergence of new bacterial pathogens and is underscored by the specter of bioterrorism. The virulence mechanisms that different pathogens use to circumvent or defeat host defense systems are mostly unknown or poorly understood. My laboratory is interested in elucidating the molecular basis of microbial virulence, which in turn will lead to new methods for prophylaxis and therapy of bacterial diseases.
Recombinant DNA methods are indispensable tools in the investigation of microbial virulence mechanisms. This technology, when used in conjunction with relevant in vitro and in vivo model systems, can be employed to define the importance of specific gene products in the pathogenesis of bacterial infections. My laboratory utilizes molecular genetic systems, DNA microarray methods, and related technologies to study two different bacterial pathogens as prototypic microbial invaders. The first of these is Moraxella catarrhalis, a common cause of upper respiratory tract infection (i.e., otitis media) in infants and young children. The second is Haemophilus ducreyi, the etiologic agent of a sexually transmitted, genital ulcer disease known as chancroid.
Research emphasis in my laboratory is placed on (1) the identification of bacterial genes that encode virulence factors, (2) the elucidation of the structure-function relationships inherent in these macromolecules, and (3) the determination of how these bacterial factors subjugate host defense mechanisms. We have already identified major virulence factors of both M. catarrhalis and H. ducreyi. Our continuing studies include the precise construction of isogenic mutants whose virulence can then be evaluated in appropriate model systems and the development of new methods for the identification of additional virulence determinants.
RESEARCH INTERESTS
Bacterial pathogenesis
RECENT PUBLICATIONS
Brooks, M.J., C.A. Laurence, E.J. Hansen, and S.D. Gray-Owen, "Characterization of the Moraxella catarrhalis Opa-like protein, OlpA, reveals a phylogenetically conserved family of outer membrane proteins" Journal of Bacteriology, 189:76-82, 2007
Wang, W., L. Reitzer, D.A. Rasko, M.M. Pearson, R.J. Blick, C. Laurence, and E.J. Hansen, "Metabolic analysis of Moraxella catarrhalis and the effect of selected in vitro growth conditions on global gene expression" Infection and Immunity, in press 2007
Hoopman, T.C., W. Wang, C.A. Brautigam, J.L. Sedillo, T.J. Reilly, and E.J. Hansen, "Moraxella catarrhalis synthesizes an autotransporter that is an acid phosphatase" J. Bacteriol., 190:1459-1472, 2008
Attia, A.S. , J.L. Sedillo, W. Wang, W. Liu, C. A. Brautigam, W. Winkler, and E.J. Hansen., "Moraxella catarrhalis expresses an unusual Hfq protein" Infect. Immun., 76:2520-2530, 2008
Deng, K., J.R. Mock, S. Greenberg, N.S.C. van Oers, and E.J. Hansen, "The Haemophilus ducreyi LspA proteins are tyrosine-phosphorylated by macrophage-encoded protein tyrosine kinases" Infect. Immun., in press 2008
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