Abstract: | The way in which cells in multicellular organisms communicate and inform each other of their presence and relative position is an intriguing but mysterious problem. The form of communication used during the phase of aggregation in the cellular slime moulds represents a particularly amenable system for study. When these organisms run short of nutrients, some of the cells of the amoebal population emit rhythmic pulses of cyclic adenosine monophosphate. These chemical signals are slowly relayed to all the other amoebae within range and bring about an ordered migration of them towards the pulsating centre and the triggering of cellular development. |