Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New microscope technology allows study of biomolecules interacting with minerals

05.08.2002


Virginia Tech student presents first findings at international geochemistry conference

Every living thing needs iron. The strategies some organisms use to accumulate iron can impact the quality of our environment and could be adapted for our use.

Imagine a falconer releasing his falcon to nab pigeons for his dinner. That is somewhat how the bacteria, Azotobacter vinelandii, acquire iron. They release siderophore molecules, called azotobactin, which nabs iron out of minerals.



"The molecule extracts the iron from the mineral and is expected to eventually return with the iron to the bacterial cell," says Treavor Kendall, a Ph.D. candidate in the mineral-microbe group in Virginia Tech’s Department of Geological Sciences.

Azotobacter vinelandiihas two things going for it. It releases millions of siderophores and these molecules have "a huge affinity for iron -- some of the highest affinities observed in nature," says Kendall.

Kendall studies how bacteria acquire iron. There have been a lot of studies on siderophores in the aqueous phase. "We do know how siderophores behave with iron in water," Kendall states, "But we don’t know how they interact with iron that is locked up in a mineral structure. This is important because minerals are a primary source of iron in the environment."

Kendall’s research is looking specifically at the affinity or forces between azotobactin and the mineral goethite -- an important iron oxide in soils worldwide.

He has been invited to present his research at the 12th Annual V.M. Goldschmidt Conference, an international geochemistry conference, Aug. 18-23, 2002 in Davos, Switzerland. His paper will be presented Thursday morning, Aug. 22, during the symposium on "Biogenic substances and their effect on trace metal cycling and mineral weathering" (S36 Wednesday p.m. and Thursday a.m.).

Kendall explains that when the molecule removes the iron from the mineral, it actually dissolves the mineral. "What happens if that mineral also contains lead or some other toxic metal? The siderophore can knock off those toxic metals, which then pollute the fresh water, marine environment, or semi-humid soil where these interactions most frequently occur."

Kendall has attached a siderophore to the microscopic plank or cantilever used in an atomic force microscope (AFM). The siderophore molecule is lowered toward the mineral surface to measure how it interacts. "The attraction is so high, that the cantilever actually snaps down to attach the molecule to the mineral," Kendall says. "When we pull it apart, like lifting your shoe off hot gum on the sidewalk, the molecule actually stretches until it breaks loose.

"Based on how much the molecule sticks, we can comment on how well siderophore likes that surface," says Kendall.

"The excitement is being able to measure the affinity between the siderophore molecule and the iron in the mineral structure."

At the conference, Kendall will report on three experiments.

"First, we are able to measure forces between the siderophore molecule and the goethite, and compare that with how siderophore interacts with diaspore, a mineral that contains aluminum. It works out as you would expect," says Kendall. "There is a higher affinity with the iron mineral.

"Next, we introduce a soluble or free form of iron. All of a sudden, the affinity goes away. This tells us that the siderophore is satisfied and no longer needs the iron in the mineral. It confirms that we are measuring what we thought," says Kendall. "So we have demonstrated the relationships and how we can make it go away.

"Third we demonstrate that the relationship doesn’t change when we alter the solution by changing the pH and ionic strength," says Kendall. "Thus, we are confident that we are measuring a specific interaction."

Potential environmental applications include anticipating toxic metal release and studying iron availability in soils.

Presently, siderophores are used in medicine to treat people who have too much iron in their blood. The siderophore locks up the iron so it is no longer toxic. The ability to measure iron affinity at the molecular level may allow researchers to refine siderophore medicinal use and detect iron concentrations in very small amounts by using them as a chemosensor. There has already been a paper exploring siderophores as chemosensors by other researchers, Kendall says.

Kendall’s major professor is Michael Hochella. Research funding is provided by the U.S. Department of Education, Kendall’s GAAN fellowship, the National Science Foundation, and the Department of Energy. The talk in Switzerland is Kendall’s first invited talk.

Originally from Houston, Kendall did his undergraduate work at the University of Texas at Austin and his master’s degree work at the University of Montana, Missoula.


Reach Kendall at tkendall@vt.edu or 540.231.8575.
He is in the lab most days from 8 a.m. to 7p.m. He leaves Aug. 17, but will be available by e-mail while in Switzerland.

Learn more about the Goldschmidt Conference at http://www.goldschmidt-conference.com/2002/gold2002/


Treavor Kendall | EurekAlert!
Further information:
http://www.technews.vt.edu/
http://www.goldschmidt-conference.com/2002/gold2002/

More articles from Life Sciences:

nachricht NUI Galway highlights reproductive flexibility in hydractinia, a Galway bay jellyfish
24.02.2020 | National University of Ireland Galway

nachricht Shaping the rings of molecules
24.02.2020 | University of Montreal

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

Im Focus: Skyrmions like it hot: Spin structures are controllable even at high temperatures

Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices

The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...

Im Focus: Making the internet more energy efficient through systemic optimization

Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.

Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.

Im Focus: New synthesis methods enhance 3D chemical space for drug discovery

After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.

"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

NUI Galway highlights reproductive flexibility in hydractinia, a Galway bay jellyfish

24.02.2020 | Life Sciences

KIST researchers develop high-capacity EV battery materials that double driving range

24.02.2020 | Materials Sciences

How earthquakes deform gravity

24.02.2020 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>