How bacteria in colonies can survive by killing siblings and reversibly changing shape

Harry L. Swinney, University of Texas at Austin
Thursday, May 17th, 7:30 pm, Michigan League Ballroom

Short Abstract
A few bacteria on a surface (e.g., skin or a medical instrument) can grow into a colony consisting of a billion bacteria and spanning several centimeters. What happens when neighboring colonies of bacteria grow and approach one another? Studies of Paenibacillus dendritiformis (a bacterium found commonly in soil) reveal that neighboring bacterial colonies mutually inhibit growth through secretions of a lethal protein. An immediate question is why doesn't this toxin kill the bacteria secreting it? A mathematical model helps answer this question. Further, sub-lethal concentrations of the toxin are found to induce the rod-shaped bacteria to switch shape to cocci, a spherical shape that is resistant to the toxin and to other antibiotics. But if the cocci encounter persistent favorable growth conditions, they switch back to rods. Thus the bacteria adapt to adverse environmental conditions by a reversible change in form.

Please register for the Public Talk on Thursday, May 17, 2012 at 7:30 pm in the Michigan League Ballroom