ULTRASTRUCTURAL ASPECTS OF THE NUCLEO-CYTOPLASMIC RELATIONSHIP OF INVAGINATED NUCLEI IN THE EPIDERMAL CELLS OF THE AXOLOTL

Abstract

The epidermal cells of axolotl possess nuclei which often show deep identations; their nuclear membrane was examined by light and electron microscopy. The nuclear envelope consists of 2 electron opaque membranes separated by an interspace and contains pores. Associated with the envelope are clouds of particles, vacuoles and bubbles of various sizes and of differing electron density. The frequency and variety of these structures suggest the passage of material of heterogeneous composition across the membrane. The structure of the envelope is similar in vesicular nuclei and in those which are deeply grooved. While the plication of the membrane seems to have little effect on its ultrastructure it may denote an increase in the nucleo-cytoplasmic interaction within its vicinity. Although the axolotl cells are considerably bigger than those of other species, cellular organelles such as the nuclear membrane, mitochondria and desmosomes are about the same size as those of human or animal cells.