I think Beata has given the correct assumption, and actually I also think you should disaggregate the cumulus cells if you want to achieve a better IVF rate

Thank you Beata, Randy and Vickram for your reply. But really it is my observation in all microdrops of IVF and also others observation. Please see this link and you will find oocyte spins "anti-clockwise"

http://pathwaybalancing.co.uk/your-conception-journey-as-a-sperm/ (Line#8)

http://www.asiaandro.com/archive/1008-682x/8/273.htm (section 2.4)

Perhaps, the anticlockwise rotation is significant and not merely a co-incidence. This movement may be helpful in bringing the egg closer to sperm and interact with ZP3? It may also be related to a gradual movement of female pronucleus toward the sperm?Again, polarity of egg may be important to bring a particular molecule on zona pellucida like a chemoattractant-a predetermined point of fertilization near to sperm.

Cumulus cells serve important functions in the human. They modify sperm-attached contraceptive glycodelin-A glycome to proconceptive glycodelin-C, which stimulates sperm-egg binding (see Chiu PC et al JBC 2007; 282: 5378). This results in charge difference of the sperm as they pass the cumulus cell layer. Any effect on the rotation?

Thank you Dr Manjeet and Dr Markku for your reply. I guess the movement of bovine oocyte that I and others observed is due to the collective group movements of the spermatozoa. Bull and human spermatozoa flagellar movement was found to be counter clockwise (in bovine it ranges from 75-100%),

http://jeb.biologists.org/content/163/1/15.full.pdf

So, imagine, millions of sperms rotate at the same time anti-clockwise, so it can generate a collective currents (waves) which are anti-clockwise too, that force the oocyte to rotate anti-clockwise.

Just a thought: do they rotate clockwise in the southern hemisphere?

I would like to share what I have found

http://www.youtube.com/watch?v=QK64Zilc0CM

Thanks to ALL

Valentin I like your question and I'll send the answer next week. My impression is they do (like that whirlpool you get as water going down the drain does) but next week when I do a run I'll quantify it.

My apologies for spraying a little water on this fire: the rotation of the oocyte is a known fact. We used to show a Japanese educational video on egg fertilization and implantation to the undergraduate students 30 years ago. The oocyte spinning was shown there very clearly and was mentioned in the comments.

And thanks Michael for testing my idea: I am really curious

In my run of 28 complexes which were spinning (4 were not - not a good sign I believe)23 were clockwise and 5 were VERY slowly anticlockwise. I tried to be careful not to do anything to induce or prevent spinning in any direction but the masses would occassionally stick together and separating them influenced things I think. Stck together masses did not spin but it takes some time for them to start.

Michael

Why would the whirlpool or even whirlwind rotate only anti-clockwise? As Holland M says, only 5 out of 28 were spinning anticlockwise and rest 23 were clockwise. Absence of spin I understand signified bad eggs?

My answer is not an answer to the question, but it's to clarify a situation I've been observing about this question for the scientific honesty of the community.

With all due respect, I believe this question is generated from an Islamic myth that anti-clockwise is preferred in natural phenomena. This question is being linked in articles claiming that the direction of rotation around "Kaaba" in Mecca, which is anti-clock, is the right way that nature "intended it" as commanded by their God "Allah". Now since the poster of the question is apparently Muslim (judging by the name and the looks and the country he's from), I can't really say he didn't intend this. But since he looks like, presumably, a well-achieving scientist, I hope he writes a clear disclaimer (especially after Holland's comment that disproves the whole claim, which begs the question on how couldn't the asker have noticed this with a 23-5 ratio!), that he never intended for this question to be taken in this direction and that this has turned out not to be true. Thank you all and sorry for the long comment.

 Thanks Dr Afach for your feedback. The question carries no religious intention as I am an embryologist and sharing my observation with my peers in this field and they also share their notions and observations. Anyway, there is a consensus that during bovine IVF, the immotile oocytes is a predictor for low fertilization ratio.

Thank you again and best wishes.