<b>Special Public Lecture</b><br>How Bacteria in Colonies Can Survive By Killing Siblings and Reversibly Changing Shape<br><b>Speaker: Professor Harry Swinney (University of Texas, Austin)</b><br>

Speaker: Professor Harry Swinney (University of Texas, Austin)

Please register for the talk by clicking here.

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.

About Professor Swinney:
Professor Harry Swinney is one of the pioneers of chaos theory, most notably for early experiments with Professor Jerry Gollub (Haverford College) on the onset of turbulence in fluid flow that provided the first experimental demonstration of deterministic chaos. He graduated from Rhodes College in 1961 with a Bachelor degree and obtained his Ph.D. from Johns Hopkins University in 1968. He is currently Sid Richardson Foundation Regents Chair and the director of the Center for Nonlinear Dynamics at the University of Texas at Austin. He is a fellow of the National Academy of Sciences.

His research is in the study of instabilities, chaos, pattern formation, and turbulence in a variety of different physical systems, with the goal of searching for an understanding of dynamical behavior that is similar in diverse systems. He is widely recognized as a leader in the study of nonlinear processes who is able to bridge the gap between dynamical systems theory, laboratory experiments and real-world applications. A few of his current research projects include the investigation of gravity waves like those that are internal to the atmosphere and oceans where the density decreases with height, which have a major effect on the Earth’s climate; instabilities in fluidized beds, where a fluid flows upward through a granular bed, such as in a gasoline refinery catalytic cracker; the formation of “viscous finger” patterns at the interface between non-mixing fluids such as oil and water; and the buckling of thin sheets such as plastic and plant leaves.

In his talk, Professor Swinney will discuss growth patterns and interactions between neighboring bacterial colonies and explain how nonlinear dynamics theory can help us understand them.

This public lecture is at the 12th Experimental Chaos and Complexity Conference. For more information on the conference please click here.