Featured Research

from universities, journals, and other organizations

New bacterial behavior: Puzzling 'dance' of electricity-producing bacteria near energy sources

Date:
December 16, 2009
Source:
University of Southern California
Summary:
Geobiologists have observed a new behavior of metal-metabolizing bacteria, with implications for design of microbial fuel cells. The bacterial 'dance' has been dubbed the electric slide, officially named electrokinesis.

Shewanella oneidensis.
Credit: Courtesy of Pacific Northwest National Laboratory

Bacteria dance the electric slide, officially named electrokinesis by the USC geobiologists who discovered the phenomenon.

Related Articles


Their study, published online in the Proceedings of the National Academy of Sciences (Early Edition), describes what appears to be an entirely new bacterial behavior.

The metal-metabolizing Shewanella oneidensis microbe does not just cling to metal in its environment, as previously thought. Instead, it harvests electrochemical energy obtained upon contact with the metal and swims furiously for a few minutes before landing again.

Electrokinesis is more than a curiosity. Laboratory director and co-author Kenneth Nealson, the Wrigley Professor of Geobiology at USC and discoverer of Shewanella, hopes to boost the power of microbe-based fuel cells enough to produce usable energy.

The discovery of electrokinesis does not achieve that goal directly, but it should help researchers to better tune the complex living engines of microbial fuel cells.

"To optimize the bacteria is far more complicated than to optimize the fuel cell," Nealson said.

Electrokinesis was discovered in 2007 by Nealson's graduate student Howard Harris, an undergraduate at the time.

Nealson had given Harris what seemed an ideal assignment for a double major in cinema and biophysics.

"I had asked him if he would just take some movies of these bacteria doing what they do," Nealson said.

Filming through a microscope is hardly simple, but with the help of co-author and biophysics expert Moh El-Naggar, assistant professor of physics and astronomy at USC, Harris was able to make a computer analysis of a time-lapse sequence of bacteria near metal oxide particles.

"Every time the bacteria were around these particles … there was a great deal of swimming activity," Nealson recalled.

Harris then discovered that bacteria displayed the same behavior around the electrode of a battery. The swimming stopped when the electrode turned off, suggesting that the activity was electrical in origin.

As is often true with discoveries, this one raises more questions than it answers. Two in particular intrigue the researchers:

  • Why do the bacteria expend valuable energy swimming around?
  • How do the bacteria find the metal and return to it? Do they sense it through an electric field or the behavior of other bacteria?

Nealson and his team so far have only educated guesses.

For the first question, Nealson believes that the bacteria may swim away from the metal because they have too many competitors.

Bacteria get energy in two steps: by absorbing dissolved nutrients and then by converting those nutrients into biologically useful forms of energy through respiration, or the loss of electrons to an electron acceptor such as iron or manganese (humans also respire through the loss of electrons to oxygen, one of the most powerful electron acceptors).

"If electrons don't flow, it doesn't matter how much food you have," Nealson said.

However, he added, "in some environments, the food is much more precious than the electron acceptors."

If a metal surface became too crowded for bacteria to absorb nutrients easily, they might want to swim away and come back.

For the second question, Harris and co-author Mandy Ward, assistant professor of research in earth sciences at USC, are planning other experiments to understand exactly how Shewanella find electron acceptors.

They expect the experiments to keep Harris busy through his doctoral thesis.

The other co-authors on the PNAS paper were Orianna Bretschger of the J. Craig Venter Institute in San Diego, Margaret Romine of Pacific Northwest National Laboratory, and Anna Obraztsova, staff scientist in the Nealson laboratory at USC.


Story Source:

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


Cite This Page:

University of Southern California. "New bacterial behavior: Puzzling 'dance' of electricity-producing bacteria near energy sources." ScienceDaily. ScienceDaily, 16 December 2009. <www.sciencedaily.com/releases/2009/12/091215141518.htm>.
University of Southern California. (2009, December 16). New bacterial behavior: Puzzling 'dance' of electricity-producing bacteria near energy sources. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2009/12/091215141518.htm
University of Southern California. "New bacterial behavior: Puzzling 'dance' of electricity-producing bacteria near energy sources." ScienceDaily. www.sciencedaily.com/releases/2009/12/091215141518.htm (accessed October 31, 2014).

Share This



More Plants & Animals News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How A Chorus Led Scientists To A New Frog Species

How A Chorus Led Scientists To A New Frog Species

Newsy (Oct. 30, 2014) A frog noticed by a conservationist on New York's Staten Island has been confirmed as a new species after extensive study and genetic testing. Video provided by Newsy
Powered by NewsLook.com
Surfer Accidentally Stands on Shark, Gets Bitten

Surfer Accidentally Stands on Shark, Gets Bitten

AP (Oct. 30, 2014) A 20-year-old competition surfer said on Thursday he accidentally stepped on a shark's head before it bit him off the Australian east coast. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Ebola Inflicts Heavy Toll on Guinean Potato Trade

Ebola Inflicts Heavy Toll on Guinean Potato Trade

AFP (Oct. 30, 2014) The Ebola epidemic has seen Senegal and Guinea Bissau close its borders with Guinea and the economic consequences have started to be felt, especially in Fouta Djallon, where the renowned potato industry has been hit hard. Duration: 02:01 Video provided by AFP
Powered by NewsLook.com
Genetically Altered Glowing Flower on Display in Tokyo

Genetically Altered Glowing Flower on Display in Tokyo

Reuters - Innovations Video Online (Oct. 30, 2014) Just in time for Halloween, a glowing flower goes on display in Tokyo. Instead of sorcery and magic, its creators used science to genetically modify the flower, adding a naturally fluorescent plankton protein to its genetic mix. Ben Gruber reports. Video provided by Reuters
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


Plants & Animals

Earth & Climate

Fossils & Ruins

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