September 28, 2009

Scientists watch E. coli bacteria move

Yale University scientists say they have, for the first time, observed and tracked E. coli bacteria moving in a liquid medium.

The researchers said their accomplishment will help lead to a better understanding of how bacteria move from place to place and, potentially, how to keep them from spreading.

Scientists have long theorized the cigar-shaped cell bodies of E. coli and other micro-organisms would follow periodic orbits that resemble the motion of a kayak paddle. But until now no one had directly observed or tracked those movements.

In the new study, Associate Professor Hur Koser, along with postdoctoral associate Tolga Kaya, said they used advanced computer and imaging technology, along with sophisticated algorithms, to take millions of high-resolution images of tens of thousands of individual, non-flagellated E. coli drifting in a water and glycerin solution, which amplified the bacteria's paddle-like movements.

The researchers characterized the bacteria's motion as a function of both their length and distance from the surface. The team said it found the longer and closer to the surface they were, the slower the E. coli paddled.

Understanding the physics of bacterial movement could potentially lead to breakthroughs in the prevention of bacterial migration and sickness, Koser said. This might be possible through mechanical means that make it more difficult for bacteria to swim upstream and contaminate water supplies, without resorting to antibiotics or other chemicals.

The study appears in the journal Physical Review Letters.