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Intracellular pressure is a motive force for cell motion inAmoeba proteus

1996; Wiley; Volume: 33; Issue: 1 Linguagem: Inglês

10.1002/(sici)1097-0169(1996)33

1097-0169

M. Yanai, Christopher M. Kenyon, James P. Butler, Peter T. Macklem, Suzanne Kelly,

Spaceflight effects on biology

The cortical filament layer of free-living amoebae contains concentrated actomyosin, suggesting that it can contract and produce an internal hydrostatic pressure. We report here on direct and dynamic intracellular pressure (Pic) measurements in Amoeba proteus made using the servo-null technique. In resting apolar A. proteus, Pic increased while the cells remained immobile and at apparently constant volume. Pic then decreased approximately coincident with pseudopod formation. There was a positive correlation between Pic at the onset of movement and the rate of pseudopod formation. These results are the first direct evidence that hydrostatic pressure may be a motive force for cell motion. We postulate that contractile elements in the amoeba's cortical layer contract and increase Pic and that this Pic is utilized to overcome the viscous flow resistance of the intracellular contents during pseudopod formation. © 1996 Wiley-Liss, Inc.