Evidence for the Regulation of the Shift in Cellulose Microfibril Orientation in Freeze-Fractured Plasma Membrane of Boergesenia forbesii

Morphological evidence regarding the regulation of the directionof movement of the cellulose-synthesizing complexes in Boergeseniawas obtained by observing the distribution of intramembranousparticles (IMPS) around the complexes. In complexes with straightconfigurations, the distribution of IMPS on both sides of thecomplexes was almost equal. In complexes characterized by acurved configuration, however, the IMPS density was greaterin the outer half-circle of the curve. Some particles on thisside were attached to or intruded into the complex, and theirsizes were no different from those of the IMPS on the fracturedplane. These results indicate that the distribution and orientationof the particles in relation to the complex have been affectedby membrane fluidity and, that membrane fluidity might playa key role in determining the regulation of the direction ofmovement of the complex. (Received July 16, 1984; Accepted October 12, 1984)