The mechanochemical basis of amoeboid movement. I. Ionic requirements for maintaining viscoelasticity and contractility of amoeba cytoplasm

D. L. Taylor, P. L. Moore, J. S. Condeelis, R. D. Allen

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16 Scopus citations


Glycerination of intact specimens and of isolated cytoplasm of Chaos carolinensis has permitted identification of the requirements for Ca2+- and Mg2+-ATP for contraction. The observed loss of some calcium sensitivity during glycerination could be explained as a combination of the extraction of an unidentified calcium sensitive factor(s), low substrate (Mg2+-ATP) contractions, or a loss of polymerizable actin. In addition, the "rigor" condition induced by complete glycerination destroyed the ability of isolated cytoplasm to stream. Decreases in cytoplasmic birefringence, in visible fibrils and in cytoplasmic contractility were observed both in glycerinated cytoplasm and in freshly isolated cytoplasm after incubation in solutions containing mM concentrations of EGTA. These results suggest that filament disassembly could be involved in the loss of birefringence and contractility of cytoplasm at low divalent cation concentrations. Furthermore, it is suggested that filament disassembly could be involved in cytoplasmic streaming if the free Ca2+ concentration were lowered below ca 1.0 × 10-7 M by an efficient calcium sequestering system.

Original languageEnglish (US)
Pages (from-to)127-133
Number of pages7
JournalExperimental Cell Research
Issue number1
Publication statusPublished - Aug 1976
Externally publishedYes


ASJC Scopus subject areas

  • Cell Biology

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