Sperm cells "smell" the egg,
i.e. they sense a chemical, called chemoattractant, produced by the egg.

The literature says that chemoattractant is contained in the egg
jelly, and diffuses into space.

My Question is now:
What is the chemoattractant concentration in the vicinity of the egg?
I am happy with an order of magnitude for a sample species
(say ~ 100 fM, ~ 10 pM, etc.)

What I already know:
* most research in on sea urchin sperm, i.e. Arbacia punctulata
* chemoattractants are resact, speract, ...

---

Request for Question Clarification by pafalafa-ga on 05 May 2006 09:59 PDT

Sperm appear to respond to concentration gradients of
chemoattractants, and have been shown to be responsive to picomolar
concentrations in laboratory settings.

I'm not aware of any work that has measured concentrations or
gradients in vivo, however.

Would laboratory studies do the trick?


pafalafa-ga

---

Clarification of Question by mam99hej-ga on 05 May 2006 12:08 PDT

No, I hoped that someone had measured the amount
of chemoattractant released by one egg, say in 1h.

I heard about these in-vitro experiments with sperm,
and of course one can argue that the eggs should produce
exactly the chemoattractant concentration gradient 
that elicited a chemotatic reponse in the lab.
However: If one could show independently, that eggs produce
the same concentration of chemoattractant as used in the
experiments, this would show that the chemotaxis mechanism
seen in the in-vitro experiments is indeed the same as used by nature
to attract sperms to the egg.

Bye Ben



My question is about concentration of chemoattractant,
when it is produced by the egg.


since I want to compare these in-vitro experiments
with the real situation.

---

Clarification of Question by mam99hej-ga on 05 May 2006 12:11 PDT

please ignore the stuff below 'bye ben'