Visualization of Bacterial Chemical Signal

First visualization of the bacterial chemical signal c-di-GMP, that regulates the bacteria's movement. Green bacteria within the aggregate of the bacteriaPseudomonas aeruginosa have higher levels of the chemical.

In reproduction of some species of bacteria, a single-celled organism will split in two and the daughter cell--the swarmer--inherits a propeller to swim freely, while the mother cell builds a stalk to cling to surfaces. Researchers at the University of Washington (UW), along with a colleague at Stanford University, designed biosensors to observe how a bacterium gets the message to divide into these two, functionally and structurally different cells. The biosensors can measure biochemical fluctuations inside a single bacteria cell, which is smaller than an animal or plant cell.

During cell division, a signaling chemical, found only in bacteria, helps determine the fate of the resulting two cells. The signal is a tiny circular molecule called cyclic diguanosine monophosphate or c-di-GMP. By acting as an inside messenger responding to information about the environment outside the bacteria cell, c-di-GMP is implicated in several bacterial survival strategies. In harmless bacteria, some of these tactics keep them alive through harsh conditions. In disease-causing bacteria, c-di-GMP is thought to regulate antibiotic resistance, adhesiveness, biofilm formation and cell motility.

The research was supported by grants from the National Institute of Allergy and Infectious Diseases of the National Institutes of Health, the Swiss National Foundation, the Novartis Foundation, the Cystic Fibrosis Foundation, and a graduate research fellowship from the National Science Foundation.