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 Shedding light on the brown color of algae
14.07.2020 | Johannes Gutenberg-Universität Mainz

nachricht New substance library to accelerate the search for active compounds
14.07.2020 | Helmholtz-Zentrum Berlin für Materialien und Energie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron cryo-microscopy: Using inexpensive technology to produce high-resolution images

Biochemists at Martin Luther University Halle-Wittenberg (MLU) have used a standard electron cryo-microscope to achieve surprisingly good images that are on par with those taken by far more sophisticated equipment. They have succeeded in determining the structure of ferritin almost at the atomic level. Their results were published in the journal "PLOS ONE".

Electron cryo-microscopy has become increasingly important in recent years, especially in shedding light on protein structures. The developers of the new...

Im Focus: The spin state story: Observation of the quantum spin liquid state in novel material

New insight into the spin behavior in an exotic state of matter puts us closer to next-generation spintronic devices

Aside from the deep understanding of the natural world that quantum physics theory offers, scientists worldwide are working tirelessly to bring forth a...

Im Focus: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

Shedding light on the brown color of algae

14.07.2020 | Life Sciences

Color barcode becomes ISO standard

14.07.2020 | Information Technology

New substance library to accelerate the search for active compounds

14.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>