SEQUENTIAL EVENTS IN BACTERIAL COLONY MORPHOGENESIS

Bacterial colonies are organized, differentiated multicellular communities expressing genetically controlled patterns. These patterns can be seen in mature colonies by staining for differential gene expression, by visualization of surface textures, and by microscopic examination of cellular morphologies and multicellular arrays. Colony morphogenesis involves many sequential processes of cellular growth, differentiation and movement which are regulated, at least in part, by cell-cell interactions and communication between groups of cells. These morphogenetic processes can be followed by periodic microscopic examination of developing colonies and by time-lapse video recordings. Since the final colony structure is the integrated product of many steps, pattern formation cannot realistically be explained by assumptions about autonomous cell behaviors. Instead, colony growth is best viewed as a developmental process in which the cells interact and adjust their individual and collective behaviors as morphogenesis proceeds.