Cellular slime mold, Dictyostelium discoideum, is unicellular amoebae. When bacterial food is available in the soil, Dictyostelium amoebae grow and divide individually. When starved, they aggregate into a multicellular slug and finally form a fruiting body, whose spores germinate into amoebae, completing the cycle. It takes about 24 hours from aggregation to spore formation. During aggregation, the amoebae communicate by periodically producing and relaying cyclic adenosine 3',5'-monophosphate (cAMP) signals. They also react chemotactically to cAMP and move towards aggregation centers.