Spindle birefringence of isolated mitotic apparatus analysed by treatments with cold, pressure, and diluted isolation medium.
نویسندگان
چکیده
Mitotic apparatus (MA) were isolated from sea-urchin zygotes using glycerol-dimethyl-sulphoxide. Cold treatment had no effect on MA birefringence when MA were in isolation medium, but caused a 10-15% reduction of MA birefringence when MA were in quarter-strength isolation medium. Pressure treatment also caused a reduction in MA birefringence, but the cold and pressure treatments were not additive, suggesting that both treatments affected the same MA component. MA were not stable in quarter-strength isolation medium, and birefringence gradually decayed, with a half-life of about 40 h. Electron microscopy after cold treatment, or after decay of 55% of the MA birefringence showed abundant, normal-looking microtubules, suggesting that alterations in non-microtubule components cause the reductions in birefringence. Addition of EGTA eliminates the effect of cold treatment, suggesting that Ca2+ has a role in maintenance of spindle structure. We discuss possible reasons why isolated MA do not respond to cold treatment like MA in vivo.
منابع مشابه
Spindle birefringence of isolated mitotic apparatus analysed by pressure treatment.
Sea-urchin zygote mitotic apparatus (MA) isolated in a glycerol/dimethylsulphoxide medium were treated with pressure. Pressure treatment had no effect on spindle birefringence when MA were in full-strength isolation medium. After placing MA in quarter-strength isolation medium, pressures of 4-0 X 10(3)-1-8 X 10(4) lbf in.-2 (2 X 76 X 10(4)-I X 24 X 10(5) k N m-2) for 15 min caused reduction of ...
متن کاملThe structure and some properties of the isolated mitotic apparatus.
The morphology of the isolated sea-urchin mitotic apparatus (MA) was examined by light and electron microscopy. With the polarization microscope and the Nomarski differential interference microscope, the isolated MAs appeared to be similar to in vivo MAs. Electron microscopy of the isolated MAs revealed the presence of microtubules, ribosome-like particles and vesicles. A close association betw...
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The sequence of mitosis in sea urchin eggs was investigated in the presence and absence of D2O. Direct observations of living cells under a polarizing microscope and observations with fixation-staining procedures were used. The duration of mitosis was extended by the presence of D2O. The slight extension of anaphase was due to elongation of the spindle in D2O, but the period from prophase to me...
متن کاملQuantitative Studies on the Polarization Optical Properties of Living Cells
Birefringence of the mitotic apparatus (MA) and its change during mitosis in sea urchin eggs were quantitatively determined using the birefringence detection apparatus reported in the preceding paper (Hiramoto et al ., 1981, J. Cell Biol. 89:115-120) . The birefringence and the form of the MA are represented by five parameters: peak retardation (SP), trough retardation (St), interpolar distance...
متن کاملCharacteristics of sea-urchin mitotic apparatus isolated using a dimethyl sulphoxide/glycerol medium.
A method for isolating sea-urchin zygote mitotic apparatus (MA) is described which is based on the Filner-Behnke method of isolating brain microtubules. MA were isolated in 50 % (v/v) glycerol, 10% (v/v) dimethyl sulphoxide, 5 mM MgCl2, o-i mM EGTA, and 5 mM Sorensen's phosphate buffer at a final pH of 6-8. MA stored at room temperature in isolation medium had stable birefringence, stable micro...
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ورودعنوان ژورنال:
- Journal of cell science
دوره 20 2 شماره
صفحات -
تاریخ انتشار 1976