Education:

1. Wet electrostatics in hierarchical self-assembly of biological systemsGerard Wong, University of Illinois at Urbana-Champaign, DMR 0804363 Bacterial biofilms are multicellular communities responsible for a broad range of persistent infections. Knowing how free-swimming bacteria adapt their motility mechanisms near surfaces is crucial for understanding biofilm development. By translating microscopy movies into searchable databases of bacterial behavior, we identify fundamental type IV pili-driven mechanisms for P. aeruginosa surface motility that enable qualitatively distinct foraging strategies. We discover a new mechanism through which bacteria stand upright and ‘walk’ with trajectories optimized for 2-D surface exploration, and show that vertical orientation facilitates surface detachment and critically influences biofilm morphology (Gibiansky et al., Science 2010, accepted) Schematic representation of bacteria ‘walking’ upright on a surface using their Type IV pili. killing peptides and membranes. This walking motility mechanism is important for early stages of biofilm development.

2. Wet electrostatics in hierarchical self-asembly of biological systemsGerard Wong, University of Illinois at Urbana-Champaign, DMR 0804363 Education: This research was started as a collaborative senior design project with three undergraduates, led by 1st year graduate student Max Gibiansky. After the undergraduates made the initial discovery of ‘walking’ bacteria by using tracking algorithms adapted from colloid physics, three post-doc’s (Jaci Conrad, Fan Jin, Vernita Gordon) joined the collaboration to give the project a strong finish. This work involved researchers with diverse backgrounds. Jaci Conrad recently started as an assistant Professor of Chemical Engineering at the University of Houston, and Vernita Gordon started as an assistant professor in Physics at University of Texas at Austin in 2010. Societal Impact: Bacterial biofilms are responsible for a broad range of problems in human health, including lethal infections in cystic fibrosis, and failure of bioengineered implants. In this work, we elucidated how bacteria that swim in liquid cultures adapt their appendages for movement on a surface. We found that bacteria can stand, walk upright, and detach from the surface using their type IV pili. The long term goal of this work is to identify new drug targets for bacterial biofilms, since these new types of movements are important for the development of biofilm morphology.