PT  - JOURNAL ARTICLE
AU  - H.V. Ramírez-Gómez
AU  - V. Jiménez-Sabinina
AU  - I. Tuval
AU  - M. Velázquez-Pérez
AU  - C. Beltrán
AU  - J. Carneiro
AU  - C.D. Wood
AU  - A. Darszon
AU  - A. Guerrero
TI  - Sperm chemotaxis is driven by the slope of the chemoattractant concentration field
AID  - 10.1101/148650
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 148650
4099  - http://biorxiv.org/content/early/2017/06/10/148650.short
4100  - http://biorxiv.org/content/early/2017/06/10/148650.full
AB  - Spermatozoa are attracted to their conspecific female gamete by diffusive molecules released from the egg investments, a process called chemotaxis. The decapeptide speract induces metabolic and permeability changes in Strongylocentrotus purpuratus sea urchin sperm. In spite of decades since speract purification from S. purpuratus egg investments, sperm chemotaxis has not been demonstrated in this species. By studying how the stimulus function, which spermatozoa experience during the accumulation of bound chemoattractants throughout their trajectory, influences both their motility response and their internal Ca2+ oscillations, we were able to show, for the first time, that S. purpuratus spermatozoa exhibit chemotaxis under sufficiently steep speract concentration gradients. We demonstrate that this process arises through frequency entrainment of the coupled metabolic oscillators.