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Fibrous Flagellar Hairs of Chlamydomonas reinhardtii Do Not Enhance Swimming

The flagella of Chlamydomonas reinhardtii possess fibrous ultrastructures of a nanometer-scale thickness known as mastigonemes. These structures have been widely hypothesized to enhance flagellar thrust; however, detailed hydrodynamic analysis supporting this claim is lacking. In this study, we pres...

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Autores principales: Amador, Guillermo J., Wei, Da, Tam, Daniel, Aubin-Tam, Marie-Eve
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Biophysical Society 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7300311/
https://www.ncbi.nlm.nih.gov/pubmed/32502384
http://dx.doi.org/10.1016/j.bpj.2020.05.003
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author Amador, Guillermo J.
Wei, Da
Tam, Daniel
Aubin-Tam, Marie-Eve
author_facet Amador, Guillermo J.
Wei, Da
Tam, Daniel
Aubin-Tam, Marie-Eve
author_sort Amador, Guillermo J.
collection PubMed
description The flagella of Chlamydomonas reinhardtii possess fibrous ultrastructures of a nanometer-scale thickness known as mastigonemes. These structures have been widely hypothesized to enhance flagellar thrust; however, detailed hydrodynamic analysis supporting this claim is lacking. In this study, we present a comprehensive investigation into the hydrodynamic effects of mastigonemes using a genetically modified mutant lacking the fibrous structures. Through high-speed observations of freely swimming cells, we found the average and maximum swimming speeds to be unaffected by the presence of mastigonemes. In addition to swimming speeds, no significant difference was found for flagellar gait kinematics. After our observations of swimming kinematics, we present direct measurements of the hydrodynamic forces generated by flagella with and without mastigonemes. These measurements were conducted using optical tweezers, which enabled high temporal and spatial resolution of hydrodynamic forces. Through our measurements, we found no significant difference in propulsive flows due to the presence of mastigonemes. Direct comparison between measurements and fluid mechanical modeling revealed that swimming hydrodynamics were accurately captured without including mastigonemes on the modeled swimmer’s flagella. Therefore, mastigonemes do not appear to increase the flagella’s effective area while swimming, as previously thought. Our results refute the longstanding claim that mastigonemes enhance flagellar thrust in C. reinhardtii, and so, their function still remains enigmatic.
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spelling pubmed-73003112020-10-10 Fibrous Flagellar Hairs of Chlamydomonas reinhardtii Do Not Enhance Swimming Amador, Guillermo J. Wei, Da Tam, Daniel Aubin-Tam, Marie-Eve Biophys J Articles The flagella of Chlamydomonas reinhardtii possess fibrous ultrastructures of a nanometer-scale thickness known as mastigonemes. These structures have been widely hypothesized to enhance flagellar thrust; however, detailed hydrodynamic analysis supporting this claim is lacking. In this study, we present a comprehensive investigation into the hydrodynamic effects of mastigonemes using a genetically modified mutant lacking the fibrous structures. Through high-speed observations of freely swimming cells, we found the average and maximum swimming speeds to be unaffected by the presence of mastigonemes. In addition to swimming speeds, no significant difference was found for flagellar gait kinematics. After our observations of swimming kinematics, we present direct measurements of the hydrodynamic forces generated by flagella with and without mastigonemes. These measurements were conducted using optical tweezers, which enabled high temporal and spatial resolution of hydrodynamic forces. Through our measurements, we found no significant difference in propulsive flows due to the presence of mastigonemes. Direct comparison between measurements and fluid mechanical modeling revealed that swimming hydrodynamics were accurately captured without including mastigonemes on the modeled swimmer’s flagella. Therefore, mastigonemes do not appear to increase the flagella’s effective area while swimming, as previously thought. Our results refute the longstanding claim that mastigonemes enhance flagellar thrust in C. reinhardtii, and so, their function still remains enigmatic. The Biophysical Society 2020-06-16 2020-05-19 /pmc/articles/PMC7300311/ /pubmed/32502384 http://dx.doi.org/10.1016/j.bpj.2020.05.003 Text en © 2020 Biophysical Society. http://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Articles
Amador, Guillermo J.
Wei, Da
Tam, Daniel
Aubin-Tam, Marie-Eve
Fibrous Flagellar Hairs of Chlamydomonas reinhardtii Do Not Enhance Swimming
title Fibrous Flagellar Hairs of Chlamydomonas reinhardtii Do Not Enhance Swimming
title_full Fibrous Flagellar Hairs of Chlamydomonas reinhardtii Do Not Enhance Swimming
title_fullStr Fibrous Flagellar Hairs of Chlamydomonas reinhardtii Do Not Enhance Swimming
title_full_unstemmed Fibrous Flagellar Hairs of Chlamydomonas reinhardtii Do Not Enhance Swimming
title_short Fibrous Flagellar Hairs of Chlamydomonas reinhardtii Do Not Enhance Swimming
title_sort fibrous flagellar hairs of chlamydomonas reinhardtii do not enhance swimming
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7300311/
https://www.ncbi.nlm.nih.gov/pubmed/32502384
http://dx.doi.org/10.1016/j.bpj.2020.05.003
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