Sperm chemotaxis is driven by the slope of the chemoattractant concentration field
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Mexico
- European Molecular Biology Laboratory, Germany
- Instituto Gulbenkian de Ciência, Portugal
- Universidad Nacional Autónoma de México, Mexico
- IMEDEA (UIB-CSIC), Spain
Abstract
Spermatozoa of marine invertebrates are attracted to their conspecific female gamete by diffusive molecules, called chemoattractants, released from the egg investments in a process known as chemotaxis. The information from the egg chemoattractant concentration field is decoded into intracellular Ca2+ concentration ([Ca2+]i) changes that regulate the internal motors that shape the flagellum as it beats. By studying sea urchin species-specific differences in sperm chemoattractant-receptor characteristics we show that receptor density constrains the steepness of the chemoattractant concentration gradient detectable by spermatozoa. Through analyzing different chemoattractant gradient forms, we demonstrate for the first time that Strongylocentrotus purpuratus sperm are chemotactic and this response is consistent with frequency entrainment of two coupled physiological oscillators: i) the stimulus function and ii) the [Ca2+]i changes. We demonstrate that the slope of the chemoattractant gradients provides the coupling force between both oscillators, arising as a fundamental requirement for sperm chemotaxis.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting files.
Article and author information
Author details
Héctor Vicente Ramírez-Gómez
Vilma Jimenez Sabinina
Funding
Consejo Nacional de Ciencia y Tecnología (Fronteras 71,Ciencia basica 252213 y 255914)
- Adán Guerrero
Consejo Nacional de Ciencia y Tecnología (Fronteras 71,Ciencia basica 252213 y 255914)
- Alberto Darszon
Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México (IA202417,IN205516,IN206016,IN215519 and IN112514)
- Adán Guerrero
Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México (IA202417,IN205516,IN206016,IN215519 and IN112514)
- Alberto Darszon
Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México (IA202417,IN205516,IN206016,IN215519 and IN112514)
- Carmen Beltran
Ministerio de Economía y Competitividad (FIS2013-48444-C2-1-P,FIS2016-77692-C2-1- P)
- Idan Tuval
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All of the animals were handled according to approved institutional animal care and use committee protocols (# 44, 142, 188, 193, 285) of the Instituto de Biotecnología of the Universidad Nacional Autónoma de México.
Copyright
© 2020, Ramírez-Gómez et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Sperm chemotaxis is driven by the slope of the chemoattractant concentration field
eLife 9:e50532.
https://doi.org/10.7554/eLife.50532
Further reading
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Explaining biodiversity is a fundamental issue in ecology. A long-standing puzzle lies in the paradox of the plankton: many species of plankton feeding on a limited variety of resources coexist, apparently flouting the competitive exclusion principle (CEP), which holds that the number of predator (consumer) species cannot exceed that of the resources at a steady state. Here, we present a mechanistic model and demonstrate that intraspecific interference among the consumers enables a plethora of consumer species to coexist at constant population densities with only one or a handful of resource species. This facilitated biodiversity is resistant to stochasticity, either with the stochastic simulation algorithm or individual-based modeling. Our model naturally explains the classical experiments that invalidate the CEP, quantitatively illustrates the universal S-shaped pattern of the rank-abundance curves across a wide range of ecological communities, and can be broadly used to resolve the mystery of biodiversity in many natural ecosystems.
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- Computational and Systems Biology
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