BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Thermodynamic limits of sperm swimming precision - Andrea Puglisi 
 (Institute for Complex Systems\, Rome)
DTSTART:20231108T090000Z
DTEND:20231108T100000Z
UID:TALK203245@talks.cam.ac.uk
DESCRIPTION:Sperm swimming is crucial to fertilize the egg\, in nature and
  in assisted reproductive technologies. Modeling the sperm dynamics involv
 es elasticity\, hydrodynamics\, internal active forces\, and out-of-equili
 brium noise. Here we give experimental evidence in favor of the relevance 
 of energy dissipation for sperm beating fluctuations.\nFor each motile cel
 l\, we reconstruct the time evolution of the two main tail's spatial modes
 \, which together trace a noisy limit cycle characterized by a maximum lev
 el of precision p_max. Our results indicate p_max&sim\;10^2 s^(&minus\;1)\
 , remarkably close to the estimated precision of a dynein molecular motor 
 actuating the flagellum\, which is bounded by its energy dissipation rate 
 according to the thermodynamic uncertainty relation. Further experiments u
 nder oxygen deprivation show that p_max decays with energy consumption\, a
 s it occurs for a single molecular motor. Both observations are explained 
 by conjecturing a high level of coordination among the conformational chan
 ges of dynein motors. This conjecture is supported by a theoretical model 
 for the beating of an ideal flagellum actuated by a collection of motors\,
  including a motor-motor nearest-neighbor coupling of strength K: When K i
 s small the precision of a large flagellum is much higher than the single 
 motor one. On the contrary\, when K is large the two become comparable. Ba
 sed upon our strong-motor-coupling conjecture\, old and new data coming fr
 om different kinds of flagella can be collapsed together on a simple maste
 r curve.\n&nbsp\;
LOCATION:Seminar Room 1\, Newton Institute
END:VEVENT
END:VCALENDAR