Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Magnetic misfits: South seeking bacteria in the Northern Hemisphere

23.01.2006


Magnetotactic bacteria contain chains of magnetic iron minerals that allow them to orient in the earth’s magnetic field much like living compass needles. These bacteria have long been observed to respond to high oxygen levels in the lab by swimming towards geomagnetic north in the Northern Hemisphere and geomagnetic south in the Southern Hemisphere. In either hemisphere, this behavior would also lead them downward in the water column into areas with their preferred oxygen level. But an unusual bacterium in New England has been found doing just the opposite, a magnetic misfit of sorts.

Scientists have dubbed the bacterium the barbell for its appearance. In a study reported in this week’s issue of Science, researchers from the Woods Hole Oceanographic Institution (WHOI) and Iowa State University used genetic sequencing and other laboratory techniques to identify the barbell, which was found coexisting with other previously described magnetotactic bacteria in a local marine pond in Falmouth, MA. They also found dense populations of a small, unidentified rod-shaped bacterium that showed a similar "backwards" behavior.

Magnetotactic bacteria concentrate large amounts of iron within their cells, far more than all other marine bacteria. They could play a significant role in iron cycling in stratified marine environments, particularly ponds and salt marshes.

Lead author Sheri Simmons of the Woods Hole Oceanographic Institution says magnetotactic bacteria are found throughout the world in chemically stratified marine and freshwater environments. They can reach high densities under the right conditions and will swim along the magnetic field axis and up or down in the water column to locate their preferred or ideal living conditions. If oxygen levels are too high or too low, they will seek a layer in the water column where the level is just right.



The scientists collected samples of the barbells and rods at Salt Pond, a marine pond that is seasonally stratified near the Woods Hole Oceanographic Institution on Cape Cod, Massachusetts. Using a rowboat and a new water sampler designed and built by WHOI engineers, the team collected samples at various depths in the pond in the summers of 2003, 2004 and 2005. Much to their surprise, they found high concentrations of bacteria that swim toward geomagnetic south when exposed to high levels of oxygen, the opposite of all previously described swimming behavior in magnetotactic bacteria. They also found magnetotactic bacteria with a mixture of north and south polarities.

The coexistence of magnetotactic bacteria with north and south polarity in the same environment contradicts the currently accepted model of magnetotaxis, which says that all magnetotactic bacteria in the Northern Hemisphere swim north and downward to reach their desired habitat when exposed to high-oxygen conditions.

Simmons and colleagues Dennis Bazylinski of Iowa State University and Katrina Edwards of WHOI studied the bacteria under laboratory conditions, and say the behavior of the bacteria in situ could be different from laboratory behavior. Their results, however, suggest new models are needed to explain how these magnetotactic bacteria behave in the environment.

"Only a few species of magnetotactic bacteria have been cultivated in the lab," Simmons said. "We need to develop more methods to do that since we cannot observe their behavior directly in the environment. We are also interested in how much iron these bacteria sequester in nature. What is their distribution and abundance, and how does that affect the chemistry of their environment?"

Shelley Dawicki | EurekAlert!
Further information:
http://www.whoi.edu/science/MCG/edwards/
http://www.whoi.edu/oceanus/viewArticle.do?id=2460&archives=true&sortBy=printed
http://www.whoi.edu/oceanus/viewArticle.do?id=3807&archives=true&sortBy=printed

More articles from Life Sciences:

nachricht Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>