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:11/22/2016)... MINNETONKA, Minn. , Nov. 22, 2016   ... that supports the entire spectrum of clinical research, is ... by Medical LiveWire Healthcare and Life Sciences Awards ... This award caps off an unprecedented year of recognition ... clinical trials for over 15 years. iMedNet ...
(Date:11/17/2016)... -- Global Market Watch: Primarily supported by ownership ... and Academics) market is to witness a value of US$37.1 ... highest Compounded Annual Growth Rate (CAGR) of 10.75% is foreseen ... period 2014-2020. North America is not ... Europe at 9.56% respectively. Report Focus: ...
(Date:11/15/2016)... ROCKVILLE, Md. , Nov. 15, 2016 /PRNewswire/ ... clinical company developing therapeutics focused on the gut ... public offering of 25,000,000 shares of its common ... its common stock at a price to the ... gross proceeds to Synthetic Biologics from the offering, ...
Breaking Biology News(10 mins):
(Date:12/4/2016)... ... 03, 2016 , ... Microbial genomics leader uBiome is awarding ... been made to Dr. Renato Polimanti of Yale University School of Medicine, who ... Grant proposals have been vetted by the company’s scientific review committee. , ...
(Date:12/2/2016)... ... 2016 , ... In anticipation of AxioMed’s exclusive cleanroom manufacturing ... President, Jake Lubinski will be traveling to Switzerland from December 5-10. Mr. Lubinski ... and Zurich to discuss the benefits of a viscoelastic disc. AxioMed received CE ...
(Date:12/2/2016)... Amgen (NASDAQ: AMGN ) and Allergan ... of a Marketing Authorization Application (MAA) to the European Medicines ... ® (bevacizumab). The companies believe this submission is the ... "The submission of ABP 215 to the EMA is ... portfolio," said Sean E. Harper , M.D., executive vice ...
(Date:12/2/2016)... ... 2016 , ... ACEA Biosciences, Inc. announced today that it will be presenting ... the World Conference on Lung Cancer 2016, taking place in Vienna, Austria December 3rd-8th. ... trials for AC0010 in patients with advanced non-small cell lung cancer harboring the EGFR ...
Breaking Biology Technology: