Wave of free calcium at fertilization in the sea urchin egg visualized with fura-2.
A wave front of increased free calcium traversing the egg at fertilization is demonstrated in the sea urchin Lytechinus pictus. The use of the fluorescent calcium chelator fura-2 in combination with low-light-level TV microscopy and image processing allows the visualization of the Ca2+ wave front with high spatial and temporal resolution. Such a wave is demonstrated as increased fluorescence after an excitation of 340-nm wavelength and as the reciprocal image in form of a reduced fluorescence when excited at 380 nm. The band-like appearance of the wave resembles the Ca2+ wave described for larger eggs of other species. In a dispermic egg the high resolution of the system used allows us to recognize two waves of Ca2+ originating from the respective points of sperm entry.
Hafner
M
M
Institute of Cell Tumor Biology, German Cancer Research Center, Heidelberg, FRG.
Petzelt
C
C
Nobiling
R
R
Pawley
J B
JB
Kramp
D
D
Schatten
G
G
D000818:Animals; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D005260:Female; D005306:Fertilization; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives*; D010063:Ovum / Q000378:metabolism*; D012617:Sea Urchins
D001572:Benzofurans; D005456:Fluorescent Dyes; C049925:fura-2-am; D002118:Calcium; D016257:Fura-2