title: In vitro fertilization and embryo culture in the grey short-tailed opossum, Monodelphis domestica.
abstract: In vitro fertilization and early embryo culture was undertaken in the South American marsupial, the grey short-tailed opossum, Monodelphis domestica. Adult females were induced into oestrus by a system of pairing with an unfamiliar male and mature oocytes were recovered from the ovary 15-18 h after mating and placed in pre-warmed modified MEM medium at 33 degrees C (basal body temperature) or 37 degrees C. Spermatozoa recovered from the cauda epididymides of adult males were preincubated in medium for 2 h during which time paired spermatozoa separated and initiated hyperactivated motility. Oocytes were transferred to 0.4 ml drops of spermatozoa containing 0.5-1.0 x 10(6) spermatozoa ml-1. Only single spermatozoa bound to the zona pellucida, and fertilization occurred within 1-2 h as indicated by a breach in the zona and confirmed by electron microscopy. At 37 degrees C, 95 of 152 (62.5%) oocytes were fertilized and 64 (67%) developed to two-cell stage or beyond. At 33 degrees C, 5 of 28 (18%) oocytes were fertilized. This is the first report of complete in vitro fertilization in a marsupial.
authors.affiliation: Institute of Zoology, Regent's Park, London, UK.
authors.forename: H D
authors.initials: HD
authors.lastname: Moore
authors.forename: D A
authors.initials: DA
authors.lastname: Taggart
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D008297:Male; D008854:Microscopy, Electron; D008858:Microscopy, Phase-Contrast; D009893:Opossums; D010063:Ovum / Q000166:cytology / Q000648:ultrastructure; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000166:cytology / Q000648:ultrastructure