Freeze-fracture examination of the plasma membrane of the cellular slime mould Polysphondylium pallidum during microcyst formation and germination.

Freeze-fracture observations of the plasma membrane of the amoebae of the cellular slime mould Polysphondylium pallidum during encystment showed a rapid increase in the density of intramembrane particles, especially in the EF face. This density remained high during the formation of the microcyst wall and then fell abruptly to the much lower values typical of the resting microcyst. During germination there was a corresponding increase in intramembrane particle density which continued to a level typical of vegetative amoebae. These results are discussed in the light of recent biochemical studies of microcyst formation, cellulose biosynthesis and microcyst germination.