Development of Microplate Motility/ Chemotaxis Assay

Saturday, October 29, 2011
Hall 1-2 (San Jose Convention Center)
Candice Devora , Microbial and Molecular Pathogenesis, Texas A&M University, College Station, College Station, TX
Robert Alaniz, PhD , Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College Station, TX
Salmonella is a pathogenic bacterium that causes infections within the human body as well as in other mammals. Salmonellae use swimming and chemotaxis to find optimal environments for survival within hosts; therefore motility is an essential factor that contributes to Salmonella virulence. Microbiologists have used “genetic screens” for decades as an essential strategy to identify important bacterial genes and pathways involved in innumerable biological processes, motility being a major one. However, genetic screens fail to achieve 100% genome coverage and are further limited by targeting single genes and potentially causing polar mutations. Thus, it is necessary to develop complementary approaches to expand our ability to target and modulate biological pathways.  We hypothesize that by using a small molecule “chemical screen” strategy, which has the potential to target not only bacterial genes but proteins, post-translational modified proteins, and non-encoded enzyme substrates; we will expand by a “quantum leap” the number of potential bacterial targets to investigate for their role in bacterial motility.

Our approach is to develop a microplate motility assay that will enable us to discover compounds that effect Salmonella motility in different microenvironments. In developing a microplate motility assay, wildtype Salmonella and motility/chemotaxis mutants are tested in the assay performed in formats of decreasing size beginning with a Petri dish moving to a 6-well plate, followed by a 24-well plate and finally a 96-well plate. We have successfully developed an assay in which we observed a similar trend with the mutants displaying decreased swimming distances compared to the wildtype.