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 Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine

nachricht New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>