Featured Research

from universities, journals, and other organizations

Amoeboid swimming: Crawling in a fluid

Date:
December 4, 2013
Source:
CNRS
Summary:
Researchers have developed a particularly simple model that reproduces the swimming mechanism of amoebas. They show that, by changing shape, these single cell organisms propel themselves forward in a viscous fluid at the same speed as when they crawl on a solid substrate. The way microorganisms swim is fundamentally different to that of fish since, at their scale, viscosity effects dominate and make fins totally inefficient.

Cell shape deformations during a swimming cycle.
Credit: © LIPhy, CNRS/UJF Grenoble

Researchers from CNRS, Inserm and Université Joseph Fourier -- Grenoble have developed a particularly simple model that reproduces the swimming mechanism of amoebas. They show that, by changing shape, these single cell organisms propel themselves forward in a viscous fluid at the same speed as when they crawl on a solid substrate.

This work has recently been published in the journal Physical Review Letters.

The way microorganisms swim is fundamentally different to that of fish since, at their scale, viscosity effects dominate and make fins totally inefficient. Various strategies are employed. The majority of such organisms propel themselves forward by beating their flagella or cilia while others, such as amoebas, deform their bodies in the same way as they would for crawling. However the efficiency of this method of propulsion remains poorly understood.

Physicists from the Laboratoire Interdisciplinaire de Physique (LIPhy, CNRS/Université Joseph Fourier Grenoble), Oslo University and the Institut Albert Bonniot (Inserm/Université Joseph Fourier -- Grenoble) have elucidated the key elements of this method of locomotion by analyzing a simplified theoretical model. They determined the necessary morphological deformations and the speed of propulsion and showed that incompressibility of the cell membrane is essential.

To conduct this study, the researchers modeled the cell using an inextensible fluid membrane (in other words, able to deform while maintaining its membrane area) containing a viscous fluid and located within a viscous fluid. Surface deformations in this model are uniquely due to forces perpendicular to the surface of the membrane. Among all the possible deformations, the physicists favored those that maintain symmetry of revolution around the axis of movement. Cell deformations induce stresses in the external fluid, which, in return, exerts a force on the cell. To simulate a swimming motion, the researchers considered elementary movements during which the forces exerted on the surface remain constant. These forces alter the shape of the cell and calculations show that motion depends solely on these shapes and not on the speed of movement.

Swimming is thus uniquely determined by the succession of shapes adopted by the cell and the distance covered only depends on the geometry of the surfaces. The model described reproduces certain swimming cycles observed in nature. It will certainly improve our knowledge of cell mobility and make it possible to envisage novel types of artificial micro-swimmers.


Story Source:

The above story is based on materials provided by CNRS. Note: Materials may be edited for content and length.


Journal Reference:

  1. Alexander Farutin, Salima Rafaï, Dag Kristian Dysthe, Alain Duperray, Philippe Peyla, Chaouqi Misbah. Amoeboid Swimming: A Generic Self-Propulsion of Cells in Fluids by Means of Membrane Deformations. Physical Review Letters, 2013; 111 (22) DOI: 10.1103/PhysRevLett.111.228102

Cite This Page:

CNRS. "Amoeboid swimming: Crawling in a fluid." ScienceDaily. ScienceDaily, 4 December 2013. <www.sciencedaily.com/releases/2013/12/131204090954.htm>.
CNRS. (2013, December 4). Amoeboid swimming: Crawling in a fluid. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2013/12/131204090954.htm
CNRS. "Amoeboid swimming: Crawling in a fluid." ScienceDaily. www.sciencedaily.com/releases/2013/12/131204090954.htm (accessed April 19, 2014).

Share This



More Matter & Energy News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Small Reactors Could Be Future of Nuclear Energy

Small Reactors Could Be Future of Nuclear Energy

AP (Apr. 17, 2014) — After the Fukushima nuclear disaster, the industry fell under intense scrutiny. Now, small underground nuclear power plants are being considered as the possible future of the nuclear energy. (April 17) Video provided by AP
Powered by NewsLook.com
Horseless Carriage Introduced at NY Auto Show

Horseless Carriage Introduced at NY Auto Show

AP (Apr. 17, 2014) — An electric car that proponents hope will replace horse-drawn carriages in New York City has also been revealed at the auto show. (Apr. 17) Video provided by AP
Powered by NewsLook.com
Honda's New ASIMO Robot, More Human-Like Than Ever

Honda's New ASIMO Robot, More Human-Like Than Ever

AFP (Apr. 17, 2014) — It walks and runs, even up and down stairs. It can open a bottle and serve a drink, and politely tries to shake hands with a stranger. Meet the latest ASIMO, Honda's humanoid robot. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
German Researchers Crack Samsung's Fingerprint Scanner

German Researchers Crack Samsung's Fingerprint Scanner

Newsy (Apr. 16, 2014) — German researchers have used a fake fingerprint made from glue to bypass the fingerprint security system on Samsung's new Galaxy S5 smartphone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins