Studies on the Cell Division of Heliozoans II. Active Role of Axopodia on Division Process and Transformation of Remnants of Cytoplasmic Connecting Bridge to New Axopodia

Abstract

The cell division of Echinosphaerium nucleofilum, strain MA, was carefully observed under differential interference optics and a polarizing microscope, by using a microchamber for side-viewing. The results were as follows : (i) organisms undergoing cell division always exhibited intensive adhesion to the glass substratum with remarkably shortened, supporting axopodia; (ii) motive force generated during cell division was considered to be derived mainly from retraction of supporting and leading axopodia located at both ends of the just-dividing organism; (iii) poly-L-lysine-coated substratum enhanced cell adhesion considerably but did not appear to result in cell division ; and (iv) remnants of cytoplasmic connecting bridges were often observed transformed to new axopodia, in which the filamentous structures showed positive birefringence.