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 Solving the efficiency of Gram-negative bacteria
22.03.2019 | Harvard University

nachricht Bacteria bide their time when antibiotics attack
22.03.2019 | Rice 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: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>