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Human sperm steer with second harmonics of the flagellar beat
Sperm are propelled by bending waves traveling along their flagellum. For steering in gradients of sensory cues, sperm adjust the flagellar waveform. Symmetric and asymmetric waveforms result in straight and curved swimming paths, respectively. Two mechanisms causing spatially asymmetric waveforms h...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5680276/ https://www.ncbi.nlm.nih.gov/pubmed/29123094 http://dx.doi.org/10.1038/s41467-017-01462-y |
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author | Saggiorato, Guglielmo Alvarez, Luis Jikeli, Jan F. Kaupp, U. Benjamin Gompper, Gerhard Elgeti, Jens |
author_facet | Saggiorato, Guglielmo Alvarez, Luis Jikeli, Jan F. Kaupp, U. Benjamin Gompper, Gerhard Elgeti, Jens |
author_sort | Saggiorato, Guglielmo |
collection | PubMed |
description | Sperm are propelled by bending waves traveling along their flagellum. For steering in gradients of sensory cues, sperm adjust the flagellar waveform. Symmetric and asymmetric waveforms result in straight and curved swimming paths, respectively. Two mechanisms causing spatially asymmetric waveforms have been proposed: an average flagellar curvature and buckling. We image flagella of human sperm tethered with the head to a surface. The waveform is characterized by a fundamental beat frequency and its second harmonic. The superposition of harmonics breaks the beat symmetry temporally rather than spatially. As a result, sperm rotate around the tethering point. The rotation velocity is determined by the second-harmonic amplitude and phase. Stimulation with the female sex hormone progesterone enhances the second-harmonic contribution and, thereby, modulates sperm rotation. Higher beat frequency components exist in other flagellated cells; therefore, this steering mechanism might be widespread and could inspire the design of synthetic microswimmers. |
format | Online Article Text |
id | pubmed-5680276 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-56802762017-11-15 Human sperm steer with second harmonics of the flagellar beat Saggiorato, Guglielmo Alvarez, Luis Jikeli, Jan F. Kaupp, U. Benjamin Gompper, Gerhard Elgeti, Jens Nat Commun Article Sperm are propelled by bending waves traveling along their flagellum. For steering in gradients of sensory cues, sperm adjust the flagellar waveform. Symmetric and asymmetric waveforms result in straight and curved swimming paths, respectively. Two mechanisms causing spatially asymmetric waveforms have been proposed: an average flagellar curvature and buckling. We image flagella of human sperm tethered with the head to a surface. The waveform is characterized by a fundamental beat frequency and its second harmonic. The superposition of harmonics breaks the beat symmetry temporally rather than spatially. As a result, sperm rotate around the tethering point. The rotation velocity is determined by the second-harmonic amplitude and phase. Stimulation with the female sex hormone progesterone enhances the second-harmonic contribution and, thereby, modulates sperm rotation. Higher beat frequency components exist in other flagellated cells; therefore, this steering mechanism might be widespread and could inspire the design of synthetic microswimmers. Nature Publishing Group UK 2017-11-10 /pmc/articles/PMC5680276/ /pubmed/29123094 http://dx.doi.org/10.1038/s41467-017-01462-y Text en © The Author(s) 2017 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
spellingShingle | Article Saggiorato, Guglielmo Alvarez, Luis Jikeli, Jan F. Kaupp, U. Benjamin Gompper, Gerhard Elgeti, Jens Human sperm steer with second harmonics of the flagellar beat |
title | Human sperm steer with second harmonics of the flagellar beat |
title_full | Human sperm steer with second harmonics of the flagellar beat |
title_fullStr | Human sperm steer with second harmonics of the flagellar beat |
title_full_unstemmed | Human sperm steer with second harmonics of the flagellar beat |
title_short | Human sperm steer with second harmonics of the flagellar beat |
title_sort | human sperm steer with second harmonics of the flagellar beat |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5680276/ https://www.ncbi.nlm.nih.gov/pubmed/29123094 http://dx.doi.org/10.1038/s41467-017-01462-y |
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