Quantitative studies on polarization optical properties of living cells III: Cortical birefringence of the dividing sea urchin egg

Cell Motility ◽  
1981 ◽  
Vol 1 (3) ◽  
pp. 387-397 ◽  
Author(s):  
Yôko Shôji ◽  
Yukihisa Hamaguchi ◽  
Y. Hiramoto
1981 ◽  
Vol 89 (1) ◽  
pp. 121-130 ◽  
Author(s):  
Y Hiramoto ◽  
Y Hamaguchi ◽  
Y Shóji ◽  
T E Schroeder ◽  
S Shimoda ◽  
...  

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 el al., 1981, J. Cell Biol. 89:115-120). The birefringence and the form of the MA are represented by five parameters: peak retardation (delta p), through retardation (delta t), interpolar distance (D1), the distance (D2) between chromosome groups moving toward poles, and the distance (D3) between two retardation peaks. Distributions of birefringence retardation and the coefficient of birefringence in the spindle were quantitatively determined in MAs isolated during metaphase and anaphase. The distribution of microtubules (MTs) contained in the spindle is attributable to the form birefringence caused by regularly arranged MTs. The distribution coincided fairly well with the distribution of MTs in isolated MAs determined by electron microscopy. Under the same assumption, the distribution of MTS in the spindle in living cells during mitosis was determined. The results show that the distribution of MTs and the total amount of polymerized tubulin (MTs) in the spindle change during mitosis, suggesting the assembly and disassembly of MTs as well as the dislocation of MTs during mitosis.


2000 ◽  
Vol 346 (3) ◽  
pp. 743-749 ◽  
Author(s):  
Keith T. JONES ◽  
Miho MATSUDA ◽  
John PARRINGTON ◽  
Matilda KATAN ◽  
Karl SWANN

A soluble phospholipase C (PLC) from boar sperm generates InsP3 and hence causes Ca2+ release when added to sea urchin egg homogenate. This PLC activity is associated with the ability of sperm extracts to cause Ca2+ oscillations in mammalian eggs following fractionation. A sperm PLC may, therefore, be responsible for causing the observed Ca2+ oscillations at fertilization. In the present study we have further characterized this boar sperm PLC activity using sea urchin egg homogenate. Consistent with a sperm PLC acting on egg PtdIns(4,5)P2, the ability of sperm extracts to release Ca2+ was blocked by preincubation with the PLC inhibitor U73122 or by the addition of neomycin to the homogenate. The Ca2+-releasing activity was also detectable in sperm from other species and in whole testis extracts. However, activity was not observed in extracts from other tissues. Moreover recombinant PLCβ1, -γ1, -γ2, -∆1, all of which had higher specific activities than boar sperm extracts, were not able to release Ca2+ in the sea urchin egg homogenate. In addition these PLCs were not able to cause Ca2+ oscillations following microinjection into mouse eggs. These results imply that the sperm PLC possesses distinct properties that allow it to hydrolyse PtdIns(4,5)P2 in eggs.


2020 ◽  
Vol 61 (44) ◽  
pp. 152460
Author(s):  
Jing Nie ◽  
Wenhao Sun ◽  
Yun Zhao ◽  
Baoxi Miao ◽  
Zhonghai Ni

Embryologia ◽  
1966 ◽  
Vol 9 (3) ◽  
pp. 170-183 ◽  
Author(s):  
TOMIO YANAGISAWA ◽  
NAOHIDE ISONO
Keyword(s):  

1954 ◽  
Vol 6 (2) ◽  
pp. 491-496 ◽  
Author(s):  
B. Hagström ◽  
Britt Hagström
Keyword(s):  

1996 ◽  
Vol 24 (1) ◽  
pp. 100S-100S
Author(s):  
Kay Ohlendieck ◽  
William J. Lennarz
Keyword(s):  

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