Electron Microscopic Studies on the Silver-stained Nucleolar Cycle of Physarum polycephalum Actin Is Localized in the Nucleolar Skeleton of Physarum polycephalum Morphological Studies on the Process of Chromosome Construction in Physarum polycephalum Actin is a Constituent of the Nuclear Matrix and Chromosome Scaffold in Physarum poly cephalum A p34cdc2-like Protein Is Localized in Both Nuclei and Cytoplasm of Physarum polycephalum Studies on RNA Transcription Activity in Interphase Nuclei in Physarum polycephalum