Minipodia and rosette contacts are adhesive organelles present in free-living amoebae.

Using scanning electron microscopy, Amoeba proteus cells migrating on the glass have been shown to develop dense coats of minipodia, which are discrete microprotrusions up to 8 microm long and approximately 0.5 microm across. They cover the middle-anterior area of the ventral cell surface, i.

Reversible changes in size of cell nuclei isolated from Amoeba proteus: role of the cytoskeleton.

Micrurgically isolated interphasal nuclei of Amoeba proteus, which preserve F-actin cytoskeletal shells on their surface, shrink after perfusion with imidazole buffer without ATP, and expand to about 200% of their cross-sectional area upon addition of pyrophosphate. These changes in size may be reproduced several times with the same nucleus. The shrunken nuclei are insensitive to the osmotic effects of sugars and distilled water, whereas the expanded ones react only to the distilled water, showing further swelling.

Surface coat shedding and axopodial movements in Actinophrys sol.

Dyes specific to the glycoproteins of the mucous coat (Alcian Blue and Ruthenium Red) and ligands cross-linking the surface receptors (γ-globulin and Concanavalin A) provoke detachment of the surface coat and shedding of mucus conglomerates outwards along axopodia in Actinophrys sol. Moreover, the two receptor-specific ligands induce rearrangement of axopodia into unipolar fan-like bundles. They arise by inclination of axopodia in one direction, usually before shedding of the surface coat.

Dissociation of membrane-cortex contacts in the hyalospheres of Amoeba proteus exposed to light-shade differences.

The hyalospheres produced by a heat shock spontaneously separated successive sheets of the cortical actin layer from the plasma membrane and retracted them inward. This phenomenon was hampered or completely inhibited by 10(4) lux white light and restored in shade. The frequency of detaching the consecutive submembrane sheets was much higher in the shade than in full light.