December 8, 2015

Researchers resolve structure of a key component of bacterial decision-making

Bacterial chemotaxis, the process by which a bacterium changes direction in response
to environmental cues, involves a complex array of chemical receptors
(red, elongated molecules) and other sensory proteins (blue and green molecules),
which work together to process sensory information. A new study offers
high-resolution details of the structure and function of the chemosensory array,
researchers report. Image and video courtesy C. Keith Cassidy

(December 8, 2015)  For bacteria that swim, determining whether to stay the course or head in a new direction is vital to survival. A new study offers atomic-level details of the molecular machinery that allows swimming bacteria to sense their environment and change direction when needed.

The study, reported in the journal eLife, represents a major step in understanding the “bacterial brain,” said University of Illinois physics professor Klaus Schulten, who led the new research.

“On its surface, a bacterium has thousands of receptors that scan the environment and then tell it what to do,” he said. This is very much like the sensory input that all animals must process. Of course, bacteria are single-celled organisms and don’t have brains, he said. But they nonetheless manage to organize and “remember” sensory signals long enough to respond to them in a way that aids their own survival.

University of Illinois physics professor Klaus Schulten, right; physics graduate student
Keith Cassidy, center; postdoctoral researcher Juan Perilla and their colleagues used
experimental data and computer simulations to determine the structure of key regions
of the “bacterial brain.” Photo by L. Brian Stauffer

The receptors on the surface of a bacterial cell detect light, chemicals, edible things and poisonous things, and transmit that information to a deeper layer of proteins, called kinases, which interpret this data and translate it into a simple choice: “Keep going” or “Change direction!”

journal reference >>