This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Intellectual Merit Most, if not all, bacteria are able to live either as independent planktonic cells or as members of organized surface-anchored communities called biofilms. Biofilm formation is thought to be a developmental process that begins when a motile bacterium (the swim stage) attaches to a surface (the stick phase). Many bacterial processes are involved in biofilm formation. One such process is flagellum-mediated motility, which facilitates attachment to and colonization of surfaces. Both motile and sessile lifestyles confer specific advantages and liabilities, therefore choosing the right one in any particular environment is crucial for bacterial adaptation and survival. A successful swim-to-stick transition requires that the bacterial cells properly sense and respond to their interaction with the surface. It is clear that bacteria can sense and respond to surfaces, but after years of research on sensory transduction pathways, we still do not understand how cells transduce information about their physical environment into their interior to alter gene expression and protein activity. Previous research has demonstrated that the bacterial flagellum, normally thought of as a helical motor that propels bacteria, acts as a sensor to monitor surface contact, and a ubiquitous flagellum-associated protein called FliL plays a central role in the response of cells to the surface. Using Proteus mirabilis as a model, the research will determine the molecular basis of FliL function in the pathway leading to gene expression and the control of the swim-or-stick lifestyle switch. Successful conclusion of this research has the potential to change the way we think about flagellar function. More importantly, it will generate clues to how cells sense and respond to physical cues in bacteria and higher organisms.
Broader Impacts The results of this research will be incorporated in well-established educational programs to train high school teachers; graduate, undergraduate and high school students, many of whom are underrepresented minorities and women; as well as to provide community kindergarten-to-gray outreach, involving students of all ages. In the broadest sense, since nearly all swimming bacteria possess a homolog of FliL, an understanding of FliL function is likely to benefit a myriad of other investigations that involve flagellum-mediated swimming, biofilm formation, and regulation of the swim-or-stick lifestyle so prevalent amongst bacteria.
