Featured Research

from universities, journals, and other organizations

A Better Way To Watch Bacteria Swim

Date:
October 5, 2009
Source:
University of Illinois at Urbana-Champaign
Summary:
Researchers have developed a new method for studying bacterial swimming, one that allows them to trap Escherichia coli bacteria and modify the microbes' environment without hindering the way they move. The new approach uses optical traps, microfluidic chambers and fluorescence to get an improved picture of how E. coli get around.

(Left to right) University of Illinois physics professor Yann Chemla, graduate student Patrick Mears, physics professor Ido Golding and graduate student Lance Min developed a technique that allows researchers to watch bacteria swim normally.

Researchers have developed a new method for studying bacterial swimming, one that allows them to trap Escherichia coli bacteria and modify the microbes' environment without hindering the way they move.

Related Articles


The new approach, described this month in Nature Methods, uses optical traps, microfluidic chambers and fluorescence to get an improved picture of how E. coli get around.

The microfluidic chambers provide a controlled environment in which the bacteria swim, and allow the researchers to introduce specific stimuli – such as chemical attractants – to see if the microbes change direction in response to that stimulus.

Optical traps use lasers to confine individual cells without impeding their rotation or the movement of their flagella. University of Illinois physics professor Yann Chemla, who co-led the study with physics professor Ido Golding, calls the optical traps "bacterial treadmills."

Movement of the bacterial cell alters the light from the laser, allowing the researchers to track its behavior.

Fluorescent markers enhance visualization of the bacteria and their flagella under a microscope.

Three to six helical flagella emerge from various points along E. coli's rod-shaped body. When they rotate in a counterclockwise fashion (as seen from behind), they gather into what looks like a coordinated bundle that pushes the bacterium forward, causing it to corkscrew through its environment. But when one or more flagella rotate in the opposite direction, they splay apart, reorienting the bacterium.

This "run and tumble" behavior has long been of interest to scientists for two reasons, Golding said. First, the elaborate mechanics of bacterial swimming "tell you a lot about biomechanics," he said. And second, "it serves as a paradigm for the way living cells process information from their environment."

Earlier studies have been unable to follow individual bacterial cells moving in three dimensions for more than about 30 seconds, the researchers said. And it is nearly impossible to determine what cues are spurring a cell to move in a given direction. The new method addresses both of these problems without altering the normal behavior of the bacterium, they found.

"Because the cell is immobilized, what we do is change the environment around it," Chemla said. "We can set up a flow cell that has two different concentrations of some chemical, for example, and see how the bacterium responds. Technically we're moving the swimming pool relative to the swimmer," he said.

The new approach allows the researchers to track a single bacterium as it swims for up to an hour, "which is orders of magnitude above what people could do before," Golding said. This will offer a new look at questions that so far have been unanswerable, he said.

"For example, some people have asked whether E. coli has a nose. Does it have a front and back?" Golding said. The team's observations indicate that while the bacterium can travel in either direction, most E. coli have "a pronounced preference" for one over the other, he said.

The researchers found that after most tumbles, a bacterium usually continued swimming in the same general direction, but that about one in six tumbles caused it to change direction completely. They were also able to quantify other features of bacterial swimming, such as changes in velocity and the time spent running and tumbling. The new technique will allow researchers to address many more questions about this model organism, they said.

"That's the typical way biology moves forward," Golding said. "You develop a new measurement capability and then you can use that to go back and look at fundamental questions that people had been looking at but had no way of answering."

The study is a project of the National Science Foundation's Center for the Physics of Living Cells at the University of Illinois, which promotes collaboration across disciplines, the researchers said.


Story Source:

The above story is based on materials provided by University of Illinois at Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University of Illinois at Urbana-Champaign. "A Better Way To Watch Bacteria Swim." ScienceDaily. ScienceDaily, 5 October 2009. <www.sciencedaily.com/releases/2009/10/091004141146.htm>.
University of Illinois at Urbana-Champaign. (2009, October 5). A Better Way To Watch Bacteria Swim. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2009/10/091004141146.htm
University of Illinois at Urbana-Champaign. "A Better Way To Watch Bacteria Swim." ScienceDaily. www.sciencedaily.com/releases/2009/10/091004141146.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Winter Can Cause Depression — Here's How To Combat It

Winter Can Cause Depression — Here's How To Combat It

Newsy (Nov. 23, 2014) Millions of American suffer from seasonal depression every year. It can lead to adverse health effects, but there are ways to ease symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Birds Around the World Take Flight

Birds Around the World Take Flight

Reuters - Light News Video Online (Nov. 22, 2014) An imperial eagle equipped with a camera spreads its wings over London. It's just one of the many birds making headlines in this week's "animal roundup". Jillian Kitchener 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