The fine structure of ceratium tripos, a marine armored dinoflagellate: II. Cytokinesis and development of the characteristic cell shape

Abstract

Cytokinesis and the subsequent development of the cell shape is examined in Ceratium tripos. Division is by binary fission with each daughter cell retaining approximately one-half of the parent theca. Separation of adjacent plates is along predetermined sutures. The cleavage furrow is bounded by the four unit membranes of the future cell covering which are continuous with those of the parent theca. Development of the cell shape proceeds concurrently with cytokinesis, and it is impossible to distinguish between the two processes. A distinct layer of microtubules located beneath the differentiating cell covering is apparently active in determining both the direction of division and pattern of development. The actual separation of daughter cells may occur subsequent to the completion of cell shape development. Formation of a new apical horn by one daughter cell, and the posterior horns by the other, is achieved in slightly different ways. Development of cell shape appears to result from an extension of the cell covering in a manner determined by the biogenesis of microtubules.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22160/1/0000591.pd