Ref ID : 4211
T. Suzaki and R.E. Williamson; Ultrastructure and Sliding of Pellicular Structures during Euglenoid Movement in Astasia longa Pringsheim (Sarcomastigophora, Euglenida). J.Protozool. 33(2):179-184, 1986
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The fine structure of cells and isolated pellicular sheets of Astasia longa is examined in relation to the sliding between neighboring pellicular strips believed to accompany euglenoid movement. Sonication break the repeating structure of the pellicle in the groove region where tannic acid fixation resolves separate but overlapping pellicular strips. All microtubules (including the two lying between the overlapping strips) remain with the inner strip. We therefore suggest that this fracture plane defines the boundary where sliding occurs between adjacent pellicular units. Consistent with this, traversing filaments running from groove to groove to connect the pellicular strips of adjacent units are displaced from transverse to oblique when elongated cells round up. In contrast, no changes suggestive of distortion within each unit are detected in the particle arrays of the ridge plasma membrane that overlies a single unit. The results are discussed in relation to previous ultrastructural studies, the site at which the force to cause sliding is generated, and the role of the traversing filaments.