Navigation Links
Team finds a better way to watch bacteria swim
Date:10/4/2009

CHAMPAIGN, Ill. 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, 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."


'/>"/>

Contact: Diana Yates
diya@illinois.edu
217-333-5802
University of Illinois at Urbana-Champaign
Source:Eurekalert  

Related biology news :

1. University of Oregon researcher finds that on waters surface, nitric acid is not so tough
2. Study finds environmental tests help predict hospital-acquired Legionnaires disease risk
3. Study finds blocking angiogenesis signaling from inside cell may lead to serious health problems
4. Study finds Viagra increases release of key reproductive hormone
5. Survey finds elevated rates of new asthma among WTC rescue and recovery workers
6. St. Jude finds factors that accelerate resistance to targeted therapy in lymphoblastic leukemia
7. Study finds a high rate of asthma in college athletes
8. Ecologist finds dire devastation of snake species following floods of 93, 95
9. Men shed light on the mystery of human longevity, study finds
10. JILA finds flaw in model describing DNA elasticity
11. Americans remain pessimistic about the environment, Stanford-AP survey finds
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Team finds a better way to watch bacteria swim
(Date:2/11/2016)... 2016  Vigilant Solutions announces today that its license plate ... by Lee,s Summit Police Department to ... arrest of a homicide suspect. Kansas City ... 65 square miles and is home to roughly 100,000 residents. ... single mobile license plate reader system and also leverages Vigilant,s ...
(Date:2/8/2016)... PRAGUE, Czech Republic , February 8, 2016 ... first EU-regulated global payment platform which presents innovation ... Voice Biometrics Authentication feature called VoiceKey. --> ... payment platform which presents innovation for clients, comfort ... feature called VoiceKey. --> Worldcore ...
(Date:2/3/2016)... , February 3, 2016 ... market research report "Automated Fingerprint Identification System Market by ... Search), Application (Banking & Finance, Government, Healthcare, and Transportation) ... MarketsandMarkets, the market is expected to be worth USD ... 21.0% between 2015 and 2020. The transformation and technology ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... Feb. 11, 2016  Neurocrine Biosciences, Inc. (NASDAQ: NBIX ) ... December 31, 2015. --> --> ... net loss of $29.3 million, or $0.34 loss per share, compared ... share for the same period in 2014. For the year ended ... million, or $1.05 loss per share, as compared to a net ...
(Date:2/11/2016)... and GERMANTOWN, Maryland , ... Frankfurt Prime Standard: QIA) today announced the introduction of ... gene expression profiling, expanding QIAGEN,s portfolio of Sample to ... researchers to select from over 20,000 human genes and ... between genes, cellular phenotypes and disease processes. --> ...
(Date:2/11/2016)... ATLANTA , Feb. 11, 2016  Spectra BioPharma ... Organization (CSO) that provides biopharma companies the experience, ... implement and deploy outsourced sales teams. Created in ... team addresses both the strategic and tactical needs ... innovative sales solutions through both personal and non-personal ...
(Date:2/11/2016)... (PRWEB) , ... February 11, ... ... business-to-business publication dedicated to delivering cutting-edge information focused on the development and ... Sciences to become a premier sponsor of the 2016 BioProcess International Awards ...
Breaking Biology Technology: