INTRACELLULAR CALCIUM AND CELL CLEAVAGE IN EARLY EMBRYOS OF XENOPUS LAEVIS
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چکیده
منابع مشابه
Intracellular Calcium and Cell Cleavage in Early Embryos of Xenopus Laevis
There is growing evidence that cell cleavage involves contraction in the region of the furrow and relaxation above the most distant parts of the spindle (see references 15 and 16) . The contractile mechanism has been likened to that of muscle, mainly as a result of studies of glycerinated models of dividing cells (7, 9) and extraction of an actomyosin-like material (8, 11) . Muscular contractio...
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We have measured levels of intracellular free calcium ([Ca2+]i) in albino Xenopus laevis embryos using recombinant aequorin and a photon-counting system. We observed sinusoidal oscillations in [Ca2+]i that had the same frequency as cleavage, with cleavage occurring when [Ca2+]i was lowest. An increase in calcium was seen to precede first cleavage. The cyclic changes in calcium were superimposed...
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In Xenopus embryos, previous results failed to detect changes in the activity of free calcium ions (Ca2+i) during cell division using Ca2(+)-selective microelectrodes, while experiments with aequorin yielded uncertain results complicated by the variation during cell division of the aequorin concentration to cell volume ratio. We now report, using Ca2(+)-selective microelectrodes, that cell divi...
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Microinjection of calcium buffers into the two-cell Xenopus laevis embryo delays cell division in a dose-dependent manner. Four calcium buffers in the BAPTA series with different affinities for calcium were used to distinguish between a localized calcium gradient regulating cleavage and the global calcium concentration regulating this event. DibromoBAPTA (Kd = 1.5 microM) was found to delay cle...
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In Xenopus, experiments performed with isolated ectoderm suggest that neural determination is a 'by default' mechanism, which occurs when bone morphogenetic proteins (BMPs) are antagonized by extracellular antagonists, BMP being responsible for the determination of epidermis. However, Ca(2+) imaging of intact Xenopus embryos reveals patterns of Ca(2+) transients which are generated via the acti...
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ژورنال
عنوان ژورنال: Journal of Cell Biology
سال: 1972
ISSN: 1540-8140,0021-9525
DOI: 10.1083/jcb.53.2.579