Salmonella bacteria cause millions of cases of food poisoning each year. Like many bacteria, Salmonella species can form biofilms – where the bacteria aggregate together in a thick extracellular matrix, or goo. Biofilms make the bugs more resistant, persistent and ultimately more virulent – in short: more difficult to kill. A bacterial protein called cyclic-di-GMP regulates biofilm formation, but it’s not known what regulates this regulator. To find out, researchers have developed a fluorescent sensor that tells them when cyclic-di-GMP levels go up or down. In the confetti-like Salmonella pictured, for example, the cells glow red when cyclic-di-GMP is low and turn yellow, then green, then blue as levels rise. Using this sensor, scientists have discovered a number of molecules that promote production of cyclic-di-GMP, including one that was particularly potent: the amino acid L-arginine. Interfering with the L-arginine to cyclic-di-GMP pathway to prevent biofilm formation could be a novel antimicrobial strategy.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC Laboratory of Medical Sciences until Jul 2023, it is now run independently by a dedicated team of scientists and writers. The website aims to engage everyone, young and old, in the wonders of biology, and its influence on medicine. The ever-growing archive of more than 4000 research images documents over a decade of progress. Explore the collection and see what you discover. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.