Featured Research

from universities, journals, and other organizations

Paramecia Adapt Their Swimming To Changing Gravitational Force

Date:
September 20, 2006
Source:
Brown University
Summary:
Using a high-powered electromagnet, Brown University physicists Karine Guevorkian and James Valles have created a topsy-turvy world for the single-celled paramecium. They have managed to increase, eliminate and even reverse the effects of gravity on the tiny protozoan, changing its swimming behavior and indirectly measuring its swimming force.

A high-powered electromagnet allowed researchers to increase, eliminate and even decrease the effects of gravity on live paramecia in a vial of pond water. (The paramecia swim harder when gravity increases.) Methods for studying a biological response to altered gravity had been few and troublesome in Earth-based laboratories.
Credit: Image : Karine Guevorkian and James Valles

For many single-celled organisms living in water, the force is always against them. The classic example is the slipper-shaped paramecium, which consistently swims harder going up than going down, just to keep from sinking. Now physicists Karine Guevorkian and James Valles of Brown University have worked out a way to turn gravity on its head and see how the creatures respond.

Related Articles


The researchers placed a vial with pond water and live paramecia inside a high-powered electromagnet at the National High Magnetic Field Laboratory in Tallahassee, Fla. The organisms are less susceptible to a magnetic field than plain water is, so the magnetic field generated inside the vial “pulls” harder on the water than on the cells. If the field is pulling down, the cells float. If it’s pulling up, they sink.

Using water alone, Valles and Guevorkian were able to increase the effect of gravity by about 50 percent. To increase the effect even further, they added a compound called Gd-DTPA* to the water. Gd-DPTA is highly susceptible to induced magnetic fields such as those generated in electromagnets. This allowed the researchers to make the water much “heavier” or “lighter,” relative to the paramecia, achieving an effect up to 10 times that of normal gravity. The magnetic field is continuously adjustable, so Valles and Guevorkian were also able to create conditions simulating zero-gravity and inverse-gravity.

By dialing the magnetic field up or down, the researchers could change the swimming behavior of the paramecia dramatically. In high gravity, the organisms swam upward mightily to maintain their place in the water column. In zero gravity, they swam up and down equally. And in reverse gravity, they dove for where the sediments ought to be.

“If you want to make something float more,” said Valles, “you put it in a fluid and you pull the fluid down harder than you pull the thing down. And that’s what we basically do with the magnet. That causes the cell to float more – and that turns gravity upside down for the cell.”

Cranking the field intensity even higher, Valles and Guevorkian could test the limits of protozoan endurance. At about eight times normal gravity, the little swimmers stalled, swimming upward, but making no progress. At this break-even point, the physicists could measure the force needed to counter the gravitational effect: 0.7 nano-Newtons. For comparison, the force required to press a key on a computer keyboard is about 22 Newtons or more than 3 billion times as strong.

Space-based research has demonstrated many puzzling biological effects related to reduced gravity, such as changes in bone cell development and gene expression. But methods for manipulating gravity in the Earth-based laboratory have been few and troublesome, hindering further research in these areas. This new method will allow researchers to subject small biological systems to gravitational effects similar to those encountered in space, allowing less expensive and more complex experiments on the biological response to altered gravity.

Valles is professor of physics at Brown University. Guevorkian, who recently received her Ph.D. at Brown, has accepted a postdoctoral position at Institut Curie in Paris. Their work on paramecia and the effects of gravity was funded by the National Aeronautics and Space Administration (NASA).

* Gadolinium-diethylene-triamine-pentaacetate


Story Source:

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


Cite This Page:

Brown University. "Paramecia Adapt Their Swimming To Changing Gravitational Force." ScienceDaily. ScienceDaily, 20 September 2006. <www.sciencedaily.com/releases/2006/09/060918163615.htm>.
Brown University. (2006, September 20). Paramecia Adapt Their Swimming To Changing Gravitational Force. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2006/09/060918163615.htm
Brown University. "Paramecia Adapt Their Swimming To Changing Gravitational Force." ScienceDaily. www.sciencedaily.com/releases/2006/09/060918163615.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA's First 3-D Printer In Space Creates Its First Object

NASA's First 3-D Printer In Space Creates Its First Object

Newsy (Nov. 26, 2014) The International Space Station is now using a proof-of-concept 3D printer to test additive printing in a weightless, isolated environment. Video provided by Newsy
Powered by NewsLook.com
Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Blu-Ray Discs Getting Second Run As Solar Panels

Blu-Ray Discs Getting Second Run As Solar Panels

Newsy (Nov. 26, 2014) Researchers at Northwestern University are repurposing Blu-ray movies for better solar panel technology thanks to the discs' internal structures. Video provided by Newsy
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. 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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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