Sperm navigation along helical paths in 3D chemoattractant landscapes.
Sperm require a sense of direction to locate the egg for fertilization. They follow gradients of chemical and physical cues provided by the egg or the oviduct. However, the principles underlying three-dimensional (3D) navigation in chemical landscapes are unknown. Here using holographic microscopy and optochemical techniques, we track sea urchin sperm navigating in 3D chemoattractant gradients. Sperm sense gradients on two timescales, which produces two different steering responses. A periodic component, resulting from the helical swimming, gradually aligns the helix towards the gradient. When incremental path corrections fail and sperm get off course, a sharp turning manoeuvre puts sperm back on track. Turning results from an 'off' Ca(2+) response signifying a chemoattractant stimulation decrease and, thereby, a drop in cyclic GMP concentration and membrane voltage. These findings highlight the computational sophistication by which sperm sample gradients for deterministic klinotaxis. We provide a conceptual and technical framework for studying microswimmers in 3D chemical landscapes.
Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
Jan F
JF
Jikeli
Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
Luis
L
Alvarez
Biological Physics, Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany.
Benjamin M
BM
Friedrich
Department of Physics, University of York, YO10 5DD Heslington, York, UK.
Laurence G
0000000166596001
LG
Wilson
Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
René
R
Pascal
Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Straße 16, 35043 Marburg, Germany.
Remy
0000000190518003
R
Colin
Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
Magdalena
M
Pichlo
Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
Andreas
A
Rennhack
Centre of Reproductive Medicine and Andrology, University of Muenster, 48149 Muenster, Germany.
Christoph
C
Brenker
Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
U Benjamin
UB
Kaupp
D000818:Animals; D047308:Arbacia / Q000502:physiology*; D002630:Chemotactic Factors / Q000494:pharmacology*; D002633:Chemotaxis / Q000502:physiology*; D008297:Male; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology*
D002630:Chemotactic Factors