ABSTRACT
Investigating the roles of chemical factors stimulating and inhibiting sperm motility is required to understand the mechanisms of spermatozoa movement. In this study, we described the composition of the seminal fluid (osmotic pressure, pH, and ions) and investigated the roles of these factors and salinity in initiating spermatozoa movement in the Pacific oyster, Crassostrea gigas. The acidic pH of the gonad (5.82±0.22) maintained sperm in the quiescent stage and initiation of flagellar movement was triggered by a sudden increase of spermatozoa external pH (pHe) when released in seawater (SW). At pH 6.4, percentage of motile spermatozoa was three times higher when they were activated in SW containing 30 mM NH4Cl, which alkalinizes internal pH (pHi) of spermatozoa, compared to NH4Cl-free SW, revealing the role of pHi in triggering sperm movement. Percentage of motile spermatozoa activated in Na+-free artificial seawater (ASW) was highly reduced compared to ASW, suggesting that change of pHi triggering sperm motility was mediated by a Na+/H+ exchanger. Motility and swimming speed were highest in salinities between 33.8 and 42.7‰ (within a range of 0 to 50 ‰), and pH values above 7.5 (within a range of 4.5 to 9.5).
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: M.B., M.S., J.C.; Methodology: E.J.A.-P., F.M., I.Q., P.P., D.R., J.L.G., M.H.; Formal analysis: M.S., E.J.A.-P., F.M., I.Q., P.P.; Writing - original draft: M.B., M.S., J.C.; Writing - review & editing: M.B., M.S., J.C.; Funding acquisition: M.S.
Funding
This work was supported by CRB-anim (ANR-11-INBS-003) and Reproseed (FP7-KBBE-2009-3). Additional funding (to M.S.) was provided by Jihočeská Univerzita v Českých Budějovicích and the South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses (CENAKVA, CZ.1.05/2.1.00/01.0024).
Supplementary information
Supplementary information available online at http://bio.biologists.org/lookup/doi/10.1242/bio.031427.supplemental
- Received November 22, 2017.
- Accepted February 20, 2018.
- © 2018. Published by The Company of Biologists Ltd
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
Article Navigation
Related articles
Cited by...
More in this TOC section
Similar articles
Other journals from The Company of Biologists
Biology Open and COVID-19
We are aware that the COVID-19 pandemic is having an unprecedented impact on researchers worldwide. The Editors of all The Company of Biologists’ journals have been considering ways in which we can alleviate concerns that members of our community may have around publishing activities during this time. Read about the actions we are taking at this time.
Please don’t hesitate to contact the Editorial Office if you have any questions or concerns.
2020 at The Company of Biologists
Despite 2020’s challenges, we achieved a lot at The Company of Biologists. In the midst of the pandemic, we have seen long-term projects and new ventures come to fruition. Read our full lowdown of 2020.
Interview- Sebastian Markert
Sebastian Markert is first author of a paper in BiO using C. elegans to model amyotrophic lateral sclerosis. In an interview, he talks about the potential implications of his work and his future plans.
Three communities to support biologists to everywhere
Online communities have never been more important. If you’re looking for somewhere to meet fellow scientists, take part in topical discussions and find virtual events in your field, take a look at each of our community sites:
- The Node: the community site for and by developmental biologists
- preLights: the preprint highlights service run by the biological community
- FocalPlane: the community site for microscopists and biologists alike