The effect of inhibitors of microtubule and microfilament function on the cellular slime mould Dictyostelium discoideum

Colchicine, vinblastine, griseofulvin and isopropyl N-phenyl carbamate (IPC) (agents which inhibit microtubule function) inhibit division of the amoebae of the cellular slime mould Dictyostelium discoideum. These inhibitors also either inhibit or delay the aggregation process characteristic of these amoebae as does cytochalasin B (CB) (an inhibitor of microfilament function). Even when apparently normal fruiting bodies are formed in the presence of these inhibitors the spores may have a diminished heat resistance (CB and IPC) and a volume which is either larger (CB), very much larger (IPC) or smaller (colchicine, vinblastine) than normal. Some of the spores that are formed in the presence of IPC resemble in shape, as well as size, those typical of diploid strains.