Sperm Can Do Calculus, Officially Smarter Than I Am

We are masters of subtlety.

As all of us already know, myself included — and I’m totally not bluffing — an ovum releases chemicals which alter the calcium concentration inside sperm and changes how fast they wag their little tails. Scientists assumed for quite some time that the concentration level controlled the style of the sperm’s swimming, with a high calcium concentration making them swim in a curved path and a low calcium concentration making them swim straight ahead.

Now German researchers at three institutions (the Caesar Research Center in Bonn, the Max Planck Institute for the Physics of Complex Systems in Dresden, and the University of Göttingen) have discovered that the calcium concentration level doesn’t determine the swimming style of the sperm they studied. What they found was surprising: sperm can do calculus. They weren’t changing their swimming style based on the total concentration level of calcium, but rather by changes in the concentration level, allowing them to find the egg regardless of how high the calcium concentration gets (eggs love their calcium).

Using an ingenious stroboscopic laser illumination – similar to that used in discotheques – the project leader Luis Alvarez was able to trace the movement of sperm in detail, and simultaneously measure the changes in the calcium concentration. The result was astonishing: the sperm tail only reacted to the time derivative of the calcium concentration and the absolute concentration was of little relevance. To put it simply: sperm can perform calculus! Exactly how they do this is unclear. The Caesar scientists suspect that sperm detect calcium ions with the help of two proteins. Calcium binds to one protein fast and to the other slow. By comparing the amount of calcium bound on both proteins can compute a “chemical derivative”, so to speak. [Max Planck Gesellschaf via Medgadget]

Yes, they studied sperm in great detail using strobe lasers similar to the type in dance clubs. And to think, I’ve been unwittingly doing very similar field research for years. . . . I told you we were subtle.

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