Malter are testing a microinjection method similar to that of the Australian groups, using a microneedle to suction up several sperm and inject them into the perivitelline space
. They have also developed a new method called zona dissection, using tiny instruments to grind and opening through the zona.
Abnormal eggs were characterized by the tearing of vitelline envelopes or rupture of yolk matrices into perivitelline spaces
. These eggs did not undergo cleavage.
On fertilization, these granules opened onto the cell surface and discharged the contents into the perivitelline space
After enucleation, the nuclear donor cells were deposited into the perivitelline space
of enucleated oocytes to facilitate close membrane contact for subsequent fusion.
However, once the fertilization membrane is raised, the perivitelline space
exceeds the length of the nuclear filament, preventing other sperm from penetrating the egg.
Fertilized eggs had a 50-[mu]m-wide perivitelline space
between the oolemma and the fertilization envelope (Fig.
Table II Permeability of the embryonic coat of Palaemonetes pugio to FITC-labeled dextrans FITC-labeled dextran molecular weight (kDa) Day of development 4.3 9.3 19.6 38.9 71.2 148.3 3 + + + [+ or -] - - 4 + + - - - - 5 + + - - - - 7 + + + [+ or -] - - 10 + + + + + - 12 + + + + + + Permeability is recorded as + (permeable) or - (nonpermeable) on the basis of the presence or absence of fluorescent dye in the perivitel-line space; [+ or -] indicates that fluorescence was found in the perivitelline space
of 50% of the eggs.
The perivitelline space
contained a refractile material that is believed to add to the HE until the next extra-embryonic envelope is formed.
In previous research, the microinjection of hexachlorobenzene into the perivitelline space
of Japanese medaka gastrulae resulted in similar heart defects[3, 4].
The fertilization membrane and a fertilization cone [ILLUSTRATION FOR FIGURE 2B OMITTED] lift off from the surface of the egg after about 34 min at 6 [degrees] C, leaving a large perivitelline space
of 65 [[micro]meter].