Featured Research

from universities, journals, and other organizations

Bacteria are more capable of complex decision-making than thought

Date:
January 19, 2010
Source:
University of Tennessee at Knoxville
Summary:
It's not thinking in the way humans, dogs or even birds think, but new findings show that bacteria are more capable of complex decision-making than previously known.

E. coli culture.
Credit: iStockphoto/Linde Stewart

It's not thinking in the way humans, dogs or even birds think, but new findings from researchers at the University of Tennessee, Knoxville, show that bacteria are more capable of complex decision-making than previously known.

Related Articles


The discovery sets a landmark in research to understand the way bacteria are able to respond and adapt to changes in their environment, a trait shared by nearly all living things, and it could lead to innovations in fields from medicine to agriculture.

In the long-term, the researchers think that scientists will be able to take the findings, published in the Proceedings of the National Academy of Sciences, and use them to tailor medicines in new ways to fight harmful bacteria or to find enhanced ways to use bacteria in agricultural or other applications.

Biology typically looks at the common bacteria Escherichia coli as the model for bacteria's ability to move actively and independently, but Gladys Alexandre, an associate professor of biochemistry, cellular and molecular biology at UT Knoxville, decided to look at the more complex soil bacterium, Azospirillum brasilense.

"As bacteria's ability to make decisions goes, E. coli is kind of dumb, which makes it easy for researchers to study sensing and information processing -- essentially, decision making -- in this bacterium," says Alexandre.

It helps to understand the way that bacteria "think." Their cells contain a number of receptors, and each one affects a certain behavior or trait in the bacteria, for example where to move, how to function, even whether to become virulent. The advent of genetic sequencing means we know more about how many receptors bacteria have, and the more receptors, the more ways a bacterium has to sense its surroundings.

E. coli has only five receptors that direct its decision-making process about movement, while Azospirillum brasilense has 48, making it comparatively much "smarter" in its ability to detect changes in its environments and as a result, to make complex decisions regarding where to move.

What scientists have not known and have been unable to study until now is how the individual receptors, by sensing their environment, directly affect the bacteria's behavior and ability to adapt to their environment. Alexandre's study is one of the first to isolate and study a receptor in this way.

She and her colleagues focused on a receptor they suspected was related to the way bacteria convert nitrogen gas from the atmosphere into a form -- ammonium -- that can be used by all organisms. This ability is called nitrogen fixation and while it is uniquely found in bacteria, it is critically important to all living organisms, as it is the only way nitrogen can eventually be incorporated into building blocks of cells.

The process is carried out by an enzyme which is damaged in the presence of high concentrations of oxygen, which presents a dilemma for the bacterium, as the energy needed for the process is usually acquired in the presence of oxygen.

When Alexandre and her team created mutant versions of the bacteria without the receptor, the mutant bacteria were unable to detect where the right position in oxygen concentration was, affecting the nitrogen fixation reaction. In other words, the mutant bacteria were somewhat "blind" and could not detect the right position, showing them their hunch was correct about the receptor's purpose. But their curiosity expanded: if they were able to uncover the receptor's purpose, would they be able to out exactly how it functioned?

For that, they enlisted the help of UT-Oak Ridge National Laboratory distinguished scientist Igor Jouline, an expert in carrying out complex computations of biological systems, such as the one governing the receptor at the heart of Alexandre's research. Working with Alexandre's data, Jouline was able to generate a model of the receptor's structure and compare it to other structures on a nearly atom-by-atom basis.

This enabled them to predict which one of the more than 100 amino acids in the sensory part of the receptor is responsible for sensing the precise oxygen concentration that this bacterium needs for nitrogen fixation. It's a process that, using normal genetic techniques, would have taken a substantial commitment of hours and resources, but was made simpler and less labor-intensive by using computing.

Alexandre hopes that other scientists and researchers can use a similar technique to look at receptor sites on other bacteria of interest. She noted that the ability to work with Jouline and with the resources available through UT Knoxville's partnership with ORNL was key to her discovery.

"Partnering with Igor provided us great insight," said Alexandre. "We would not have been able to fully understand how this receptor works without him."

Alexandre says there's good long-term potential for the knowledge gained in the study.

"We see now that bacteria are, in their way, big thinkers, and by knowing how they 'feel' about the environment around them, we can look at new and different ways to work with them."


Story Source:

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


Journal Reference:

  1. A PAS-domain containing chemoreceptor couples dynamic changes in metabolism and chemotaxis. Proceedings of the National Academy of Sciences, January 12, 2010

Cite This Page:

University of Tennessee at Knoxville. "Bacteria are more capable of complex decision-making than thought." ScienceDaily. ScienceDaily, 19 January 2010. <www.sciencedaily.com/releases/2010/01/100114143310.htm>.
University of Tennessee at Knoxville. (2010, January 19). Bacteria are more capable of complex decision-making than thought. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2010/01/100114143310.htm
University of Tennessee at Knoxville. "Bacteria are more capable of complex decision-making than thought." ScienceDaily. www.sciencedaily.com/releases/2010/01/100114143310.htm (accessed October 24, 2014).

Share This



More Plants & Animals News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. 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


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