RUI: The Role of Outer Membrane Agglutinins In Bacterial Colonization

Haverford College, Haverford PA

Investigators

Abstract

Intellectual Merit Certain bacteria can colonize external, mucosal and intracellular sites of eukaryotes. Colonization is promoted by proteins on the outer surface of bacteria that mediate interactions with eukaryotic cells, solid surfaces, or other bacteria. This project focuses on the agglutinins, a family of outer membrane proteins expressed by a broad repertoire of Gram-negative bacteria ranging from human intestinal colonizers to intracellular colonizers of insects. Our laboratory has shown that the Heat Resistant Agglutinin 1 (Hra1) is an accessory colonization factor in Escherichia coli strains with exceptional colonization abilities. This project will examine interplay of this protein with other surface factors, such as fimbriae, using cultured epithelial cells and the nematode worm Caenorhabditis elegans as model systems. The research will additionally identify and validate colonization-associated motifs within Hra1 and related proteins from other intestinal colonizers. The investigations will be extended to Wolbachia Surface Proteins (Wsps). Wsps are agglutinins hypothesized to contribute to localization and interbacterial interactions of bacteria that reside inside the cells of insects and nematodes. To get around difficulties with culturing and manipulating Wolbachia, we propose to study the Wsps by expressing them in E. coli and to apply the methods we are using to examine E. coli surface proteins towards elucidating Wsp function. This work will advance the understanding of interactions among bacteria as well between bacteria and their eukaryotic hosts. Broader impact: Knowledge gained from this project will increase understanding of specific molecular interactions that allow bacteria to live on or in other organisms. The research will be conducted at Haverford College, a small liberal arts institution and will largely be performed by mentored undergraduate researchers. The PI teaches microbiology and introductory genetics, stimulating interest in bacteriology in a number of undergraduates and will offer 3-8 students each year, including women and other groups underrepresented in the sciences, research opportunities associated with the project. Additionally, approximately 30 students a year will be taught in inquiry-based lab classes that test some hypotheses associated with the project. As in the past, some students so trained will work with the PI in microbiology workshops for K-12 students in the US or for students and Faculty in West Africa.