Ref ID : 4754
Andrzej Grebecki; Bidirectional Transport of Extracellular Material by the Cell Surface of Locomoting Saccamoeba limax. Arch.Protistenk 136:139-151, 1988
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The movement of latex spheres and some other particles along a migrating S. limax has two components. The majority of particles flow forwards at the same rate as the cell locomotion rate or slightly faster. This anterograde transport is manifested by the particles which seem to be loosely attached to the cell surface and is transmitted even to those remaining in suspension. It is ectoplasm independent: the particles overtake the ectoplasmic granules and the outline of the cell contour. The second component, which may occur in the same time and in the same place is, on the contrary, ectoplasm-dependent. It is manifested only by the particles firmly attached to the surface (probably by adhesion), which move exactly in the same manner as the ectoplasmic layer on the opposite side of the membrane. Their transport is, therefore, always retrograde relatively to the cell position. In respect to the ground, they move backwards along the frontal fountain zone, are stationary at the intermediate cell-to-substratum attachment zone, and on the tail surface are transported forwards but slower than the cell locomotion rate. It is presumed that the first component reflects the flow of the fluid lipid fraction of the cell membrane, while the second the behaviour of surface receptors engaged in the adhesion of the particles, which are linked to the submembraneous contractile cell cortex.