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PubMed · 8521456

Calcium diffusion coefficient in Myxicola axoplasm.

N F al-Baldawi·R F Abercrombie
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Abstract

Calcium diffusion coefficients were measured in Myxicola axoplasm and in agar controls by two independent techniques: one utilizing 45Ca, and one utilizing Ca-specific mini-electrodes. The lowest value, approximately 0.1 x 10(-6) cm2.s-1, was measured, using the mini-electrode technique, in axoplasm with intact Ca-sequestering organelles. With ATP-depleted axoplasm, diffusion coefficients of 0.5-2 x 10(-6) cm2.s-1 were obtained by both isotope and mini-electrode techniques. In organelle-free axoplasm with a protein concentration roughly half that in the intact axoplasm, diffusion coefficients of 1.4-3 x 10(-6) cm2.s-1 were measured at 0.7 microM Ca and 7 x 10(-6) cm2.s-1 at 3-5 microM Ca. When compared with measurements of the calcium buffering capacity [Al-Baldawi NF. Abercrombie RF. (1995) Cytoplasmic Ca buffer capacity determined with Nitr-5 and DM-nitrophen. Cell Calcium, 17, 409-422], these diffusion coefficients require that part of the buffer capacity be located on mobile Ca-binding sites.

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AgarAnimalsAxonsCalciumDialysisDiffusionElectrochemistryElectrodesOrganellesPolychaetaComparative StudyJournal ArticleResearch Support, U.S. Gov't, P.H.S.

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N F al-Baldawi, R F Abercrombie. 1995. Calcium diffusion coefficient in Myxicola axoplasm.. https://doi.org/10.1016/0143-4160(95)90088-8

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