Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers reveal mystery of bacterial magnetism

24.10.2006
Scientists at the Naval Research Laboratory (NRL) and Purdue University have shed light on one of microbiology's most fascinating mysteries--why some bacteria are naturally magnetic. Their description of how being magnetic "helps" the bacteria is reported in the August 2006 issue of the Biophysical Journal.

Magnetic bacteria are found in a variety of aquatic environments, such as ponds and lakes. The strain of bacterium the research team studied, Magnetospirillum magneticum, was originally found in a pond in Tokyo, Japan. Magnetic bacteria typically live far below the surface, where oxygen is scarce. (They do not grow well where oxygen is plentiful.) What makes them fascinating is that they naturally grow strings of microscopic magnetic particles called magnetosomes. When placed in a magnetic field, the bacteria align like tiny swimming compass needles, a phenomenon call magnetotaxis.

The research team is using genetic engineering to create a strain of the bacteria that become magnetic only when exposed to specific toxic chemicals, with the goal of using them as living chemical sensors. As a first step, they have created a strain that cannot make magnetosomes and therefore is not magnetic. Dr. Lloyd Whitman from NRL, who led the research team, explains that "during the course of our research, we realized that nobody had ever really demonstrated that being magnetic actually helps the bacteria." "Genetic modification allowed us to directly observe differences in behavior between magnetic and non-magnetic versions of the same bacterium," adds Professor Bruce Applegate. Professor Applegate directed the genetic engineering at Purdue, with the assistance of Professor Lazlo Csonka, Dr. Lynda Perry, and Ms. Kathleen O'Connor.

In the past, scientists had suspected that being magnetic helps a bacterium find the oxygen concentrations it prefers more quickly by swimming only up and down in the earth's magnetic field rather than randomly in all directions. An analogy would be a blind-folded mountain climber searching for a specific altitude. If she only climbs straight up or down the mountain, she should find it more quickly. "But by observing how the bacteria moved away from oxygen that we added to their environment," reports Dr. McRae Smith, a member of the team while a postdoctoral researcher at NRL, "we directly measured how much magnetotaxis helps." NRL researcher Dr. Paul Sheehan adds, "by mathematically modeling their motion, we determined that being magnetic actually makes the bacteria much more sensitive to oxygen when in a magnetic field, so that they swim away from oxygen at much lower concentrations." It is as if the climber gets tired and turns around sooner when heading up the mountain, keeping her from heading too far in the wrong direction. And the stronger the magnetic field, the bigger the effect. The scientists do not yet know how the magnetic field has this affect on the bacteria, and are currently conducting additional experiments to help answer that question.

... more about:
»Magnetic »NRL »bacteria »magnetic field

What was particularly interesting to the scientists was that the affect of being magnetic was too small for them to measure in the earth's natural, but weak, magnetic field. "Therefore," concludes Dr. Whitman, "the advantage to these bacteria in nature must be very small." "But over millions of years, this very subtle advantage has somehow produced bacterial magnetism."

NRL Public Affairs | EurekAlert!
Further information:
http://www.nrl.navy.mil

Further reports about: Magnetic NRL bacteria magnetic field

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>