On the Interrelations between the Macronucleus and the Cytoplasm in the Gymnostome Ciliate Chlamydodon pedarius

Some interrelations between the macronucleus and cytoplasm in the gymnostome ciliate Chlamydodon pedarius have been studied by means of the electron microscope.The aggregates of the small particles about 100Å to 200Å diameter located in the cytoplasm adjacent to the nuclear envelope are seen to be continuous with the loose and collapsing structures of the nucleoli through the pores of the nuclear envelope. The nucleoli are located beneath the nuclear envelope with the intercalary zones, through which the strand-like connections are found to be traversing from the nucleoli to the nuclear extrusions.The perinuclear cytoplasm of the macronucleus could be interpreted as a site of the organization of mitochondria or at least mitochondria precursors with the efficient materials from both the macronucleus and cytoplasm.The anterior part of the old macronucleus shows that a certain dissolving of the nucleolar structure might probably concur with a shrinkage of the nuclear membrane and it causes the extrusion of the nucleolar materials into the cytoplasm.The electron micrographs of the sections through the right and left plane of the macronucleus show that the contours on the right and left. surfaces of the macronucleus are dissimilar, in addition to a structural difference in the anterior and posterior halves of the macronucleus. These differences suggest that the morphologically and the physiologically complex nature of the cytoplasm might necessitate the local specializations of the phenomena in the macronucleus.