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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Video: As the Sperm Swims
17 September 2012 3:00 pm
Most sperm, it turns out, aren't straight swimmers: They tend to follow a curved path. A new imaging technique small enough to fit on a computer chip has yielded never-before-seen insights into the swimming patterns of the human sperm. High-powered microscopes can show cellular structures in exquisite detail, but those instruments' field of view is too small to follow the paths of swiftly moving microorganisms. So an engineering team from the University of California, Los Angeles, has sidestepped that obstacle by getting rid of the lens. Using their chip-based, holographic imaging method, the researchers tracked the swimming patterns of some 1500 human sperm cells over several hours. Reporting today in the Proceedings of the National Academy of Sciences, the researchers found that about 90% of sperm cells swim along a slightly curved axis. Another 4% to 5% follow a corkscrew path (see video). And for some reason, the vast majority of these helical swimmers (90%) like to form a helix that curves to the right. These right-handers, though, only began to appear when the sperm were extracted from the semen they typically swam in and placed into a laboratory fluid used for imaging. It's possible, the authors write, that for reasons unknown, human semen suppresses the sperm cells' more unusual swimming patterns. The new technique, the researchers say, isn't just useful for observing sperm locomotion—it can also open a window into the twists and turns taken by bacteria and other microorganisms.
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