Transformation of the flagella and associated flagellar components during cell division in the coccolithophoridPleurochrysis carterae

Summary Immunofluorescence microscopy, conventional and high voltage transmission electron microscopy were used to describe changes in the flagellar apparatus during cell division in the motile, coccolithbearing cells ofPleurochrysis carterae (Braarud and Fagerlund) Christensen. New basal bodies appear alongside the parental basal bodies before mitosis and at prophase the large microtubular (crystalline) roots disassemble as their component microtubules migrate to the future spindle poles. By prometaphase the crystalline roots have disappeared; the flagellar axonemes shorten and the two pairs of basal bodies (each consisting of one parental and one daughter basal body) separate so that each pair is distal to a spindle pole. By late prometaphase the pairs of basal bodies bear diminutive flagellar roots for the future daughter cells. The long flagellum of each daughter cell is derived from the parental basal bodies; thus, the basal body that produces a short flagellum in the parent produces a long flagellum in the daughter cell. We conclude that each basal body in these cells is inherently identical but that a first generation basal body generates a short flagellum and in succeeding generations it produces a long flagellum. At metaphase a fibrous band connecting the basal bodies appears and the roots and basal bodies reorient to their interphase configuration. By telophase the crystalline roots have begun to reform and the rootlet microtubules have assumed their interphase appearance by early cytokinesis.Abbreviations CR1, CR2 crystalline roots 1 and 2 - CT cytoplasmic tongue microtubules - DIC differential interference contrast light microscopy - H haptonema - HVEM high voltage transmission electron microscopy - IMF immunofluorescence microscopy - L left flagellum/basal body - M metaphase plate - MT microtubule - N nucleus - R right flagellum/basal body - R1, R2, R3 roots 1, 2, and 3 - TEM transmission electron microscopy