Hydrodynamic functionality of the lorica in choanoflagellates

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Hydrodynamic functionality of the lorica in choanoflagellates. / Asadzadeh, Seyed Saeed; Nielsen, Lasse Tor; Andersen, Anders; Dölger, Julia; Kiørboe, Thomas; Larsen, Poul S.; Walther, Jens H.

In: Journal of the Royal Society. Interface, Vol. 16, No. 150, 20180478, 2019.

Research output: Contribution to journalJournal article – Annual report year: 2019Researchpeer-review

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@article{37c70621dc8d47eab7d87c9c35001ebc,
title = "Hydrodynamic functionality of the lorica in choanoflagellates",
abstract = "Choanoflagellates are unicellular eukaryotes that are ubiquitous in aquatic habitats. They have a single flagellum that creates a flow toward a collar filter composed of filter strands that extend from the cell. In one common group, the loricate choanoflagellates, the cell is suspended in an elaborate basket-like structure, the lorica, the function of which remains unknown. Here, we use Computational Fluid Dynamics to explore the possible hydrodynamic function of the lorica. We use the choanoflagellate Diaphaoneca grandis as a model organism. It has been hypothesized that the function of the lorica is to prevent refiltration (flow recirculation) and to increase the drag and, hence, increase the feeding rate and reduce the swimming speed. We find no support for these hypotheses. On the contrary, motile prey are encountered at a much lower rate by the loricate organism. The presence of the lorica does not affect the average swimming speed, but it suppresses the lateral motion and rotation of the cell. Without the lorica, the cell jiggles from side to side while swimming. The unsteady flow generated by the beating flagellum causes reversed flow through the collar filter that may wash away captured prey while it is being transported to the cell body for engulfment. The lorica substantially decreases such flow, hence it potentially increases the capture efficiency. This may be the main adaptive value of the lorica.",
keywords = "Lorica, Choanoflagellates, Computational fluid dynamics, Low Reynolds number flow, Filter feeders, Microswimmers",
author = "Asadzadeh, {Seyed Saeed} and Nielsen, {Lasse Tor} and Anders Andersen and Julia D{\"o}lger and Thomas Ki{\o}rboe and Larsen, {Poul S.} and Walther, {Jens H.}",
year = "2019",
doi = "10.1098/rsif.2018.0478",
language = "English",
volume = "16",
journal = "Journal of the Royal Society. Interface",
issn = "1742-5689",
publisher = "The/Royal Society",
number = "150",

}

RIS

TY - JOUR

T1 - Hydrodynamic functionality of the lorica in choanoflagellates

AU - Asadzadeh, Seyed Saeed

AU - Nielsen, Lasse Tor

AU - Andersen, Anders

AU - Dölger, Julia

AU - Kiørboe, Thomas

AU - Larsen, Poul S.

AU - Walther, Jens H.

PY - 2019

Y1 - 2019

N2 - Choanoflagellates are unicellular eukaryotes that are ubiquitous in aquatic habitats. They have a single flagellum that creates a flow toward a collar filter composed of filter strands that extend from the cell. In one common group, the loricate choanoflagellates, the cell is suspended in an elaborate basket-like structure, the lorica, the function of which remains unknown. Here, we use Computational Fluid Dynamics to explore the possible hydrodynamic function of the lorica. We use the choanoflagellate Diaphaoneca grandis as a model organism. It has been hypothesized that the function of the lorica is to prevent refiltration (flow recirculation) and to increase the drag and, hence, increase the feeding rate and reduce the swimming speed. We find no support for these hypotheses. On the contrary, motile prey are encountered at a much lower rate by the loricate organism. The presence of the lorica does not affect the average swimming speed, but it suppresses the lateral motion and rotation of the cell. Without the lorica, the cell jiggles from side to side while swimming. The unsteady flow generated by the beating flagellum causes reversed flow through the collar filter that may wash away captured prey while it is being transported to the cell body for engulfment. The lorica substantially decreases such flow, hence it potentially increases the capture efficiency. This may be the main adaptive value of the lorica.

AB - Choanoflagellates are unicellular eukaryotes that are ubiquitous in aquatic habitats. They have a single flagellum that creates a flow toward a collar filter composed of filter strands that extend from the cell. In one common group, the loricate choanoflagellates, the cell is suspended in an elaborate basket-like structure, the lorica, the function of which remains unknown. Here, we use Computational Fluid Dynamics to explore the possible hydrodynamic function of the lorica. We use the choanoflagellate Diaphaoneca grandis as a model organism. It has been hypothesized that the function of the lorica is to prevent refiltration (flow recirculation) and to increase the drag and, hence, increase the feeding rate and reduce the swimming speed. We find no support for these hypotheses. On the contrary, motile prey are encountered at a much lower rate by the loricate organism. The presence of the lorica does not affect the average swimming speed, but it suppresses the lateral motion and rotation of the cell. Without the lorica, the cell jiggles from side to side while swimming. The unsteady flow generated by the beating flagellum causes reversed flow through the collar filter that may wash away captured prey while it is being transported to the cell body for engulfment. The lorica substantially decreases such flow, hence it potentially increases the capture efficiency. This may be the main adaptive value of the lorica.

KW - Lorica

KW - Choanoflagellates

KW - Computational fluid dynamics

KW - Low Reynolds number flow

KW - Filter feeders

KW - Microswimmers

U2 - 10.1098/rsif.2018.0478

DO - 10.1098/rsif.2018.0478

M3 - Journal article

VL - 16

JO - Journal of the Royal Society. Interface

JF - Journal of the Royal Society. Interface

SN - 1742-5689

IS - 150

M1 - 20180478

ER -