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posted by martyb on Sunday August 02 2020, @12:11AM   Printer-friendly
from the they-otter-check-again dept.

Human sperm swim more like otters than eels, study finds:

For more than 300 years, most scientists have assumed that sperm "swim" through fluids by wriggling their tails back and forth like eels to propel themselves forward. But according to a new paper in Science Advances, this is actually an optical illusion—the result of viewing the creatures from above with 2D microscopes. New observations with 3D microscopy have revealed that human sperm actually roll as they swim, like otters, essentially corkscrewing themselves forward.

"With over half of infertility caused by male factors, understanding the human sperm tail is fundamental to developing future diagnostic tools to identify unhealthy sperm," said co-author Hermes Gadelha from the University of Bristol.

[...] Back in 1977, physicist Edward Purcell did some calculations that showed how animals of different sizes would swim at different Reynolds numbers. The number would be very high for a whale, for instance, which is able to coast a good distance with a single flap of its tail. According to Purcell's calculations, however, bacteria swim at low Reynolds numbers, so they can barely coast any distance at all if you push them to set them in motion. It's akin to a human trying to swim in molasses and moving their arms at slow speeds on par with the movement of a clock's hands. So eels and sperm (or bacteria) would adopt very different swimming strategies by necessity because they are dealing with different Reynolds numbers.

[...] One such strategy might be to break the symmetry of the stroke to create more drag on the power stroke than on the recovery stroke. A creature could do this by changing the shape of the "paddle"—for example, the cilia that cells use to propel themselves forward. Bacteria and sperm, in contrast, have helical tails they can use as a corkscrew-like propeller. This latest study sheds some intriguing light on precisely how this works for human sperm. (Of course, as Bhatia pointed out, "Don't expect to see human swimmers doing 'the corkscrew' anytime soon. This strategy works only at low Reynolds number, where water 'feels' as thick as cork, so you can push against it effectively.")

Fertility clinics today still rely on 2D views when examining sperm movement, so this new work provides a better understanding of how the sperm tail moves, which could in turn lead to better diagnostic tools. "This discovery will revolutionize our understanding of sperm motility and its impact on natural fertilization," said co-author Alberto Darszon from the Universidad Nacional Autonoma de Mexico, who pioneered the 3D microscopy technique with his colleague and co-author Gabriel Corkidi. "So little is known about the intricate environment inside the female reproductive tract and how sperm swimming impinge on fertilization. These new tools open our eyes to the amazing capabilities sperm have."

Journal Reference:
Osborne Reynolds. An experimental investigation of the circumstances which determine whether the motion of water shall be direct or sinuous, and of the law of resistance in parallel channels, Philosophical Transactions of the Royal Society of London (DOI: https://royalsocietypublishing.org/doi/10.1098/rstl.1883.0029)

E. M. Purcell. Life at low Reynolds number, American Journal of Physics (DOI: 10.1119/1.10903)

Hermes Gadêlha, Paul Hernández-Herrera, Fernando Montoya, et al. Human sperm uses asymmetric and anisotropic flagellar controls to regulate swimming symmetry and cell steering [open], Science Advances (DOI: 10.1126/sciadv.aba5168)


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  • (Score: -1, Spam) by Anonymous Coward on Sunday August 02 2020, @01:04AM (1 child)

    by Anonymous Coward on Sunday August 02 2020, @01:04AM (#1030112)

    Marissa Van Eck FAKENAME CUNT Azuma Hazuki: So "that was NOT me posting" https://soylentnews.org/comments.pl?noupdate=1&sid=37033&page=1&cid=985641#commentwrap [soylentnews.org] which YES, you said when you LIBELED me publicly BEFORE it with YOU saying "So that's a "yes" to schizophrenia/schizoaffective disorder and a "no" to "am taking meds for said disorder" LIBELING ME then...?" per YOUR https://soylentnews.org/comments.pl?noupdate=1&sid=37033&page=1&cid=982854#commentwrap [soylentnews.org] you stupid pitiful FAKENAME fuck online LIAR piece of fucking SHIT?

    OR

    Was it when I GOT YOUR REAL NAME & found you are a satanist/anti-god HERE https://redeeminggod.com/sermons/luke/luke_7_36-50/#comment-269796 [redeeminggod.com] also which most ALL you "LEFTIST" LOSER weirdos usually are (which YES, in THIS other exchange "Why do you assume that you finding discussion threads on other sites with me in them will scare me?" quoted from https://soylentnews.org/comments.pl?noupdate=1&sid=38720&page=1&cid=1028402#commentwrap [soylentnews.org] you DID admit FINALLY to saying it was you - ESPECIALLY AFTER dozens of doctors RECENTLY seconded me on Hydroxychloroquin + Zinc (& Vitamin D3 imo along w/ other things I noted that are anti-viral + antibacterial like RAW GARLIC too)).

    Do me a favor - DENY ANY OF THOSE, please & I will continue PROVING YOU ARE A SHITBAG LOSER, devil... as I already DID here https://soylentnews.org/comments.pl?noupdate=1&sid=38720&page=1&cid=1028211#commentwrap [soylentnews.org]

    The TRUE BEAUTY of SATANIST FUCKS like YOU (antigod assholes)? TRUTH & FACT DESTROYS LIBELOUS DEVILS LIKE YOU - just like I did you & OTHER AHOLES who doubted what I wrote on what is NOW PROVEN TRUE by DOCTORS, admitted in mainstream media etc. (as I showed in those links' exchanges above easily) & especially LATELY by DOZENS of doctors (I have proof from pros - NOT LIBEL like you did to me PUBLICLY & I can still FRY YOU FOR IT FUCKER, live in fear fuck) MINUS any psych pros backing you.

    SAY 1 THING, YOU STINKING LIBELOUS FUCK & I will CONTINUE LEVELLING YOU PUBLICLY with facts - not libel as you tried on me, stupid "Marissa von DUMBO", lol - please, say 1 thing & the BEATING on you, PUBLICLY will continue in this thread where you will have a HELL of a TIME "downmod burying it" via downmod brigades doubtless ONLY yourself via multiple sockpuppet accounts etc. (downodding to HIDE it? FORGET IT vs. me - everyone sees you @ it now, lol - thanks, just as I SAID "your kind", demonic SWINE/antigod LOSERS, always do).

    WHY SHOULD YOU FEAR LIBELING ME PROJECTING IT NOW, TRYING TO HIDE IT TOO?

    TOUGH HIDING YOU LIED about LIBELING ME, especially via INHERENTLY DAMAGING STATEMENTS libeling me as you did see GOLDWATER RULE below too fuckface CUNT you are (wikipedia proof https://soylentnews.org/comments.pl?noupdate=1&sid=37033&page=1&cid=985366#commentwrap [soylentnews.org] & you said "No jury or judge would back it" here https://soylentnews.org/comments.pl?noupdate=1&sid=37033&page=1&cid=985353#commentwrap? [soylentnews.org] Ok - like I said earlier here which you TRIED TO DOWNMOD HIDE as I knew you HAVE to (everyone sees it anyhow) - TRY ME FUCKER - say 1 thing you COWARDLY STUPID LITTLE FUCK & we'll SEE what happens to you, fuckface CUNT you are).

    As I said "DO YOU WANT TO BE SUED" for breaking the GOLDWATER RULE? See here again https://soylentnews.org/comments.pl?noupdate=1&sid=37033&page=1&cid=985329#commentwrap [soylentnews.org] for YOUR (& everyone else's) reference of YOUR LIBEL of myself

    APK

    P.S.=> Oh, I am going to have a FIELDDAY on YOUR ASS fucker - catching you not ONLY IN LIES above, but also in the fact you are a GODLESS fucking LOSER - come on, say something, question the above where you LIED fucker ("it was not me saying it" but it WAS in those links calling me a nutcase essentially when YOU SAID YOU DID NOT (because it IS grounds for SUING THE LIFE OUT OF YOUR WORTHLESS ASS because your statements are NOT BACKED BY actual psychiatric pros in professional psychiatric grounds LIBELING ME)) - oh, you are NEVER going to LIVE THIS DOWN & believe you me - I am going to MAKE SURE you don't - live with your HUMILIATION loser... apk

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  • (Score: 0) by Anonymous Coward on Sunday August 02 2020, @01:21AM

    by Anonymous Coward on Sunday August 02 2020, @01:21AM (#1030119)

    Dear psycho, when was the last time you had yourself tested?

    Be sure to show your shrink your posting history.