Transmission and scanning electron microscopy of changes associated with microcyst formation in the myxamoebae of Physarum polycephalum.

Surface and internal changes associated with transition from myxamoebal to microcyst stages in Physarum polycephalum have been observed with transmission and scanning electron microscopy. Nuclear morphology, granules studded with ribosomal-like particles, synthesis of polysaccharides which are deposited exterior to the cell, and origin of material for the cell wall appear to be similar in the amoeba and in the plasmodium. In addition, the viability of the strain used in this research after being allowed to remain in a quiescent or encysted stage was observed to be approximately six months.