350 likes | 484 Views
Lecture 16: Fertilization. Animal Science 434 John J. Parrish. Capacitation. 1951 Austin - rat Chang - rabbit Fertilization does not occur until several hours after sperm are placed in the uterus or oviduct. Chang Experiment - 1951. Ovulation. After. Before. Percent Fertilization.
E N D
Lecture 16: Fertilization Animal Science 434 John J. Parrish
Capacitation • 1951 • Austin - rat • Chang - rabbit • Fertilization does not occur until several hours after sperm are placed in the uterus or oviduct
Chang Experiment - 1951 Ovulation After Before Percent Fertilization
Capacitation The changes within sperm that confer upon the sperm the ability to acrosome react in response to the appropriate stimulus. • Zona Pellucida • Cumulus Cells • Follicular Fluid
Epididymal Ejaculated Capacitated Seminal Plasma and/or Epididymal Secretions Female Tract + + Effect of Capacitation
Model of Capacitation D F Acrosome Nucleus Cytoplasm Plasma Membrane
GAG D F Acrosome Nucleus Cytoplasm Plasma Membrane
Chol-Acceptor GAG D F Ca2+ pH cAMP Ca2+ Cholesterol Acrosome Nucleus Activity of Enzymes Cytoplasm Plasma Membrane
Capacitation • No change in sperm morphology • Motility change • hyperactivation cAMP Power output
Fused Plasma Membrane and Outer Acrosomal Membrane The Acrosome Reaction Plasma Membrane Acrosin Hyaluronidase Acrosome Nucleus
Modification of the Equitorial Region
The Zona Pellucida ZP1 ZP2 ZP3
Sperm Interaction with the Zona Attachment Zona Pellucida Binding ZP3 Acrosome Reaction Induction Acrosome Reaction
ZP2 ZP2 ZP2 ZP2 Secondary Binding Zona Pellucida Zona Penetration Motility
6-12 hr 18-24 hr
MPF MPF MPF MPF Maturation Promoting Factor(MPF) LH Surge Metaphase Promoting Factor Primary Oocyte GVBD Metaphase I GV-Intact PB-1 Ovulation Metaphase II Secondary Oocyte
Ca2+ Ca2+ Ca2+ Ca2+ Zona Pellucida Oocyte Perivitelline Space
Ca2+ Ca2+ Ca2+ Ca2+ Zona Pellucida Oocyte Perivitelline Space
Ca2+ Ca2+ Ca2+ Ca2+ Zona Pellucida Oocyte Perivitelline Space
Ca2+ Ca2+ Ca2+ Ca2+ Zona Pellucida Oocyte Perivitelline Space
Ca2+ Ca2+ Ca2+ Ca2+ Zona Pellucida Oocyte Perivitelline Space
Initiation of Calcium Pulse by Soluble Sperm Component DAG Oocyte PIP2 PLCzeta IP3 Ca2+ Ca2+ Endoplasmic Reticulum
Sperm Receptor - Calcium Pulse Initiation PLC Ca++ IP3 ER
Pronuclei Ca2+ AII X TII MII PBII Zona Pellucida Oocyte MPF Perivitelline Space
Decondensation Pronuclei Pronuclei Ca2+ AII X TII MPF MII PBII Zona Pellucida Oocyte Zygote Perivitelline Space
Ca2+ Cortical Granules Zona Pellucida Oocyte Zona Block to Polyspermy Perivitelline Space
Ca2+ Zona Pellucida Oocyte Zona Block to Polyspermy Cortical Granules Perivitelline Space
Blocks to Polyspermy Species 1. Mammals 3. InvertebratesAmphibiansFishRabbits 4. AmphibiansAvians 1 2 3 4