Morphogenesis in dictyostelium: an orbital hypothesis.

Free-living amoebae of Dictyostelium discoideum aggregate when deprived food, guided by the intercellular transmission of signals of adenosine 3',5'-monophosphate. A succession of multicellular forms is then constructed, each with a circular cross section in every plane normal to its central axis. Amoebae are in constant circular and helical motion around the circumference of these structures. A theory is proposed wherein the sustained progagation of waves of cyclic adenosine 3',5'-monophosphate secretion in cellular loops determines their circumference and thereby organizes morphogenesis in this organism.