Contractile basis of ameboid movement. VII. Aequorin luminescence during ameboid movement, endocytosis, and capping.
D L Taylor,J R Blinks,G Reynolds +2 more
TLDR
The localization of both distinct actin structures and sites where [Ca++] increases suggests cellular sites of contractile activity, which can be viewed in relation to the solation-contraction coupling hypothesis defined in vitro.Abstract:
Aequorin luminescence has been utilized to determine the spatial and temporal fluctuations of the free calcium ion concentration [Ca++] in Chaos carolinensis during ameboid movement, pinocytosis, and capping. The [Ca++] increases above approximately 10(-7) M during normal ameboid movement. Three types of luminescent signals are detected in cells: continuous luminescence, spontaneous pulses, and stimulated pulses. Continuous luminescence is localized in the tails of actively motile cells, and spontaneous pulses occur primarily over the anterior regions of cells. We are sometimes able to correlate the spontaneous pulses with extending pseudopods, whereas stimulated pulses are induced by mechanical damage, electrical stimulation, concanavalin A-induced capping, and pinocytosis. The localization of both distinct actin structures and sites where [Ca++] increases suggests cellular sites of contractile activity. The independent evidence from localizing actin structures and the distribution of [Ca++] can also be viewed in relation to the solation-contraction coupling hypothesis defined in vitro.read more
Citations
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Measurement of Ca2+ concentrations in living cells
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Microtubules and the endoplasmic reticulum are highly interdependent structures.
TL;DR: It is concluded that microtubules and the ER are highly interdependent in two ways: polymerization of individual micro Tubules and extension of individual ER tubules occur together at the level of resolution of the fluorescence microscope, and depolymerization of micro Tubule leads to a slow retraction of the ER network towards the cell center, indicating that over longer periods of time, the extended state of the entire ER network requires the microtubule system.
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Fluorescence and bioluminescence measurement of cytoplasmic free calcium.
Peter H. Cobbold,T J Rink +1 more
TL;DR: The technique has been rapidly developed with the invention of the superior dyes, fura-2 and indo1, and technologies for monitoring [Ca2], in single cells, whole fields of identified cells, and even localized areas within cells, with improvements in time resolution down to the millisecond range.
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Calcium-dependence of catecholamine release from bovine adrenal medullary cells after exposure to intense electric fields.
D. E. Knight,P. F. Baker +1 more
TL;DR: By subjecting isolated adrenal medullary cells to intense electric fields of brief duration it is possible to gain access to the cell interior without impairing the ability of the cell to undergo exocytosis.
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Migration of zebrafish primordial germ cells: a role for myosin contraction and cytoplasmic flow.
Heiko Blaser,Michal Reichman-Fried,Irinka Castanon,Karin Dumstrei,Florence L. Marlow,Koichi Kawakami,Lilianna Solnica-Krezel,Carl-Philipp Heisenberg,Erez Raz +8 more
TL;DR: It is demonstrated that zebrafish primordial germ cells whose migration is guided by SDF-1 generate bleb-like protrusions that are powered by cytoplasmic flow.
References
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Control of cytoplasmic actin gel–sol transformation by gelsolin, a calcium-dependent regulatory protein
Helen L. Yin,Thomas P. Stossel +1 more
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A free calcium wave traverses the activating egg of the medaka, Oryzias latipes.
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Calcium transients in isolated amphibian skeletal muscle fibres: detection with aequorin.
TL;DR: There was a progressive reduction in both the amplitude and the rate of decline of the aequorin response during trains of isometric contractions, an observation consistent with the theory that Ca is redistributed from sites of release to sites of sequestration under such circumstances.
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Calcium transients in aequorin-injected frog cardiac muscle.
TL;DR: The Ca2+-sensitive bioluminescent protein aequorin was microinjected into cells of frog at rial trabeculae to study intracellular calcium transients associated with excitation–contraction coupling.
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Aequorin luminescence: relation of light emission to calcium concentration--a calcium-independent component.
TL;DR: Light emission from the calcium-sensitive bioluminescent protein aequorin was measured at calcium ion concentrations of 10(-9) to 10(-2) molar and the complete relation is well described by a two-state model involving three calcium-binding sites.