AS 434 – Gamete Transport, Capacitation and Fertilization
Student 1:
Student 2:
Student 3:
Student 4:
Date:
1. What is the speed of sperm migration in cervical mucus that you observe?
2. How long would it take sperm to migrate through a cow cervix of 10 cm?
3. Would the speed have been different if we had used diestrus mucus?
4. Sperm migration tests are often used to evaluate quality of a human ejaculate. What types of
infertility could be detected with this test and could you use bovine mucus as a substitute for human
mucus? If you did use human mucus, when during the menstrual cycle would you collect the
mucus?
5. Given the nature of random collisions between sperm and oviduct cells in the co-culture such as you
were shown, over sufficient time, would the sperm saturate all binding sites on the oviduct cells?
6. What intracellular changes in sperm do you think could trigger such a dramatic change in motility
pattern to the hyperactivated state? Consider the second messenger system that the hormone
epinephrine uses in your answer. In google, I found the following site on how epinephrine works.
Once on the site, click on the narrated version so it will play through without you needing to keep
clicking.
7. Why is there a need to use LH, FSH and estradiol during the in vitro maturation protocol?
8. During in vivo fertilization, in what part of the mammalian reproductive tract does sperm-oocyte
binding occur?
9. Does the movie of sperm-oocyte interaction in vitro accurately reflect what happens in vivo in the
reproductive tract? Why or why not?
10. After isolating sperm with the swimup procedure, you used the hemocytometer to determine the
sperm concentration? Why do you even need to bother with this and why not use the
spectrophotometer?
11. Fill in the motility table from the Percol column results.
Fraction
Medium
1 top
extender
2
45% Percoll
% Motile
3
45% Percoll
4
45% Percoll
5
45% Percoll
6
90% Percoll
7
90% Percoll
8
90% Percoll
9 bottom
90% Percoll,
sperm pellet
12. Describe in your own words what happened to the sperm in the different fractions of the Percol
gradient?
13. Why do you think the sperm separated on the Percol gradient as they did?
14. What was added to the fertilization medium to capacitate bovine sperm? What would happen to the
success of fertilization if this substance was omitted?
15. During IVF it is often neccessary to add 1000 to 10,000 sperm per oocyte in order to get
fertilization. What does this tell you about the ability to capacitate sperm in vitro and the efficiency
of the oocyte to block polyspermy during IVF?
16. Determine the status of each object available for evaluation and report the percentage of objects in
each sample that were germinal vesicle (GV), metaphase (MI or MII), fertilized (monospermic and
polyspermic) and polyspermic fertilized. Did your group agree on all objects and their status? What
percentage of your oocytes placed with sperm have a chance of development to term?
17. What are the symptoms of this disease in dogs, cats and pigs?
18. Define the acronym SMEDI.
19. Why is this disease of such importance in the pig industry?
20. What are the relationship between the dog and cat versions of this virus?
21. After viewing the Wikipedia links, do you think humans can be infected with the canine parvovirus?