Amphibian cross-fertilization and polyspermy.
A string of oocytes from Bufo arenarum (Ba) was inseminated with spermatozoa from Ba, Leptodactylus chaquensis (Lch), or Bufo paracnemis (Bp). Homologous insemination resulted in monospermic eggs and normal development, while in the case of heterologous fertilization both polyspermy and abnormal development were the rule. Oocytes from Ba inseminated with homologous spermatozoa, when reinseminated 30 sec after the first insemination with heterologous spermatozoa, exhibit a high rate of polyspermy and abnormal development. A lower rate of abnormalities was observed when reinsemination was carried out 60 sec after the first insemination. Normal development and an absence of polyspermy were observed in the case of eggs reinseminated 300 sec after initial insemination. This result indicated that the electrophysiological blockage of fertilization either was not triggered or was ineffective. The establishment of the permanent blockage of polyspermy, either by artificial activation of oocytes or as a result of their incubation with the products of the cortical granules, inhibited penetration of Ba eggs by heterologous sperm.
Gómez
M I
MI
Instituto de Biología, Facultad de Bioquímica, Química y Farmacia, San Miguel de Tucumán, Argentina.
Cabada
M O
MO
D000818:Animals; D001001:Anura; D002025:Bufonidae; D002462:Cell Membrane / Q000502:physiology; D003433:Crosses, Genetic; D003594:Cytoplasmic Granules / Q000502:physiology; D005260:Female; D005306:Fertilization; D006824:Hybridization, Genetic; D066298:In Vitro Techniques; D008297:Male; D013045:Species Specificity; D013094:Spermatozoa / Q000502:physiology*; D014817:Vitelline Membrane / Q000502:physiology