Sientists have discovered that sperm have a previously unrecognized skill –
they can swim in a “slither” mode when they are close to the wall of their environment.
The motion of a slithering sperm cell resembles that
of a snake wriggling across the desert floor – the head of the sperm points in o
ne direction and the long tail ripples back and forth behind it, propelling the cell in a straight line. All of the action happens in a two-dimensional plane.
This is in contrast to all other known modes of sperm locomotion, which
scientists have dubbed “typical,” “helical,” “hyper-helical,” “hyper-activated” and “chiral ribbons.” These swimming methods require the tail of a sperm cell to move in three dimensions, using a
corkscrew-type pattern.
A team of scientists from the University of Toronto uncovered the existence of slithering sperm by studying semen from humans and bulls. The scientists, led by engineering graduate student Reza Nosrati, used an imaging technique called total internal reflection fluorescence microscopy. This allowed them to measure the movements of sperm that were a mere one-trillionth of a meter away from
the bottom of a glass dish. (For the sake of comparison, that distance is 50 to 80 times smaller than the length of an entire sperm cell.)
The closer the sp
erm cells were to the edge of the dish, the more likely they were to swim in slither mode. For human sperm, viscosity was a factor too –
the more viscous the environment, the more likely they were to slither.
http://www.latimes.com/science/scien...110-story.html
Video at the website link
