Recent advances in the social and developmental biology of the myxobacteria

The myxobacteria are gram-negative prokaryotes in the delta group of the Proteobacteria. They go through a complex developmental cycle that involves group behavior as well as rudimentary multicellularity. This review summarizes and evaluates the recent research on such areas as cell-cell signaling mediated by extracellular signals as well as by cellular appendages, social motility, rippling, tactic behavior, fruiting body and myxospore morphogenesis, retrons, developmental regulation, the role of light and carotenoids, phase variation, and antibiotic production. Although the myxobacteria are unequivocally prokaryotic, they manifest a number of properties more frequently found among the eukarya, such as serine-threonine kinases, calmodulin-like proteins, steroids, a phosphatidylinositol cycle, and reverse transcriptase. The myxobacteria may have been Nature's earliest experiment in multicellularity.