Bacteria are simple, single-cell organisms that lack the nervous systems and brains of higher life forms. Strange as it may seem, however, the little creatures have a rudimentary form of memory, according to two researchers at the Berkeley campus of the University of California. After performing an intriguing series of experiments, the scientists reported to the annual meeting of the American Chemical Society that the common intestinal bacterium Salmonella typhimurium can recall things in its past.
Biochemists Robert M. Macnab and Daniel Koshland were investigating a characteristic that S. typhimurium shares with many other bacteria: it responds strongly to changes in external...