Abstract
In axenic strains of Dictyostelium discoideum, approximately one-fourth of vegetative amoebae were multinucleated throughout the growth phase, and synchronous mitosis were observed in these cells. In contrast to vegetative amoebae, all spores of these strains were mononucleated. The percentage of multinucleated amoebae in strain A-3 increased to nearly 70 % when the temperature was raised to 27°C from 22°C, but it decreased during prolonged incubation at 27°C. Karyokinesis proceeded at a constant rate even at 27°C. These results indicate that cytokinesis in this strain is not co-ordinated with karyokinesis. The number of multinucleated cells was drastically reduced in amoebae grown on both live and dead bacteria. Polystyrene latex particles, the diameter of bacteria, did not affect the rate of production.
