( Scientists have discovered a new phenom...)One bacteria stops another on contact

The discovery by a team of scientists working in the laboratory of David Low, professor of biology at the University of California, Santa Barbara, is reported in the August 19 issue of the journal Science. The findings indicate that Escherichia coli, one culprit in urinary tract infections, contains genes that when turned on block the growth of other E. coli bacteria that they touch. The finding was a complete surprise to the scientists, said Low.

The discovery may eventually lead to new antimicrobial agents to halt bacterial growth which would be an entirely new system to shut bacteria down, according to the scientists. "This has potential implications for new antibiotics," said Low. "If bacteria can do this, then maybe we can do it."

Doctoral student and first author Stephanie Aoki, and a team of scientists working in the Low lab, made the discovery while studying other aspects of E. coli. After working for two years, the team identified two genes required for this "stop on contact" phenomenon.

"We don't know if these 'stopped' cells are dead or alive," said Low. "They don't grow after they've been touched. They don't grow on plates, but laboratory stains show they may be alive. You might call them dead, but they don't break apart the way dead cells do. These cells appear to stay intact, perhaps in a quiescent mode, or dormant state."

Aoki explained, "We are currently exploring how contact between bacteria can inhibit cell growth �� and determining what this contact-dependent inhibition of growth (CDI) system is used for. These genes are present in E. coli, including uropathogenic E. coli that cause urinary tract infections, a
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Source:University of California - Santa Barbara