ISSN:
0003-276X
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
The fine structural appearance of eight spontaneously polyspermic rabbit zygotes was studied. The zygotes were considered polyspermic only after they met all criteria that excluded other possibilities of the trinucleate state. The presence of accessory male pronuclei, with varying degrees of disintegration of their chromatin in zygotes of similar age, suggests that refertilization can occur during an interval of several hours after penetration of the primary sperm. All of the polyspermic zygotes contained cortical granules intermittently beneath the vitelline (plasma) membrane. One zygote possessed cortical granule-like structures with ill-defined or no limiting membrane. Formation of enveloping membranes around the incorporated accessory sperm head was precocious since it occurred prior to disintegration of the chromatin. Advanced stages of accessory pronuclei morphologically resembled the primary pronuclei in the same zygote. In seven out of eight zygotes the accessory male pronucleus was separated from the apposing male and female pronuclei. It was concluded that although the fully expanded accessory male pronucleus is similar to the pronuclei of monospermic fertilization, the temporal events of nuclear envelope formation were disturbed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ar.1091790210
