Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Protective Shield against the Heavy Metal Uranium

06.06.2016

Microorganisms can better withstand the heavy metal uranium when glutathione is present, a molecule composed of three amino acids. Scientists from the German based Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Bern in Switzerland have now proven this resilience by closely examining cell heat balance. They discovered that glutathione is an effective decontamination agent. The studies provide important insights into bioremediation of mining waste piles and other contaminated areas with the help of bacteria or plants.

Living cells are small power stations in which various chemical reactions take place, releasing tiny amounts of heat. Metabolism is stimulated when the cells are exposed to uranium, without, however, leading to increased growth.


If uranium is built into the molecule glutathione, the chemical toxicity of the heavy metal decreases.

HZDR / Karim Fahmy

This extra effort is detectable in the organisms as increased heat emission – signaling their fight against the toxin. The four-person team from Dresden and Bern (Dr. Muhammad H. Obeid, Dr. Jana Oertel, Prof. Marc Solioz, Prof. Karim Fahmy) established a highly sensitive method, known as microcalorimetry, with which this power can be measured – even if it lies only in the microwatt (a millionth of a watt) range.

Through their tests, the researchers furthermore determine the culture cell count and thus register how the cells divide and grow. Karim Fahmy summarizes the results: “We have found out that the metabolism with uranium becomes less efficient. The cells produce more heat but not more cells. They’re virtually running a temperature!”

The organisms clearly use their energy for defense mechanisms rather than for growth. A completely different picture emerges when glutathione is present. In this case, the cells continue to grow. “Glutathione lowers uranium’s chemical toxicity. The cells better withstand the contamination," says the biophysicist.

A bacterium from cheese production, Lactococcus lactis, was chosen for the studies. The researchers used a strain with an artificially introduced hereditary predisposition for glutathione production. The gene can be selectively switched on or off. This allows precise control of whether the cells produce glutathione or not. Karim Fahmy explains, “We thereby have a clean model and do not need to add the glutathione from the outside.” Disruptive factors are thus excluded.

These new insights on the protective effects of glutathione are important for innovative strategies in biological heavy metal decontamination in the environment. The process known as bioremediation attempts to harness plants or bacteria for the removal of toxins from contaminated sites. The organisms absorb the contaminants, which are removed from the site under controlled conditions through a subsequent “harvest”. The procedure also appears suitable for uranium decontamination. As is clear from the HZDR researchers’ findings, a preference should be given to organisms with their own glutathione biosynthesis.

Glutathione has already been discussed for quite a long time as a decontaminant because it is an antioxidant and, for example, renders free radicals harmless. Until now, however, strong proof of its protective effects against uranium has been lacking. The Dresden researchers have now made up for this lack. The results are particularly significant because they were obtained from living organisms.

An insoluble and therefore non-toxic complex

The researchers could also gain further insights on how the interaction between heavy metals and glutathione works. Karim Fahmy says, “We see that uranium binds to the carboxyl group of glutathione. This results in an insoluble complex that is no longer toxic.” This applies to the concentrations studied, 10 to 150 micromolar uranium – a content which is typically found at contaminated sites in the German Ore Mountains. Comparative measurements showed that for copper, entirely different reactions occur within the cells. Glutathione fails to deploy any protective effects here.

Measuring metabolic warming for environmentally relevant risk evaluation of heavy metals is intensely promoted at the Institute of Resource Ecology at the HZDR. The unique opportunity to also work with radioactive materials at the institute results in entirely new insights on the effects of low concentrations of radionuclides in organisms, relevant in the fields of medicine and environmental biology.

Publication: Muhammad H. Obeid, Jana Oertel, Marc Solioz, Karim Fahmy, „Mechanism of attenuation of uranyl toxicity by glutathione in Lactococcus lactis“, in: Applied and Environmental Microbiology, June 2016 (doi:10.1128/AEM.00538-16)

Further information:
Prof. Dr. Karim Fahmy
Institute of Ressource Ecology at the HZDR
Phone +49 0351 260-2952 | Email k.fahmy@hzdr.de

Media contact:
Christine Bohnet | Press spokesperson
Phone +49 351 260-2450 | Email c.bohnet@hzdr.de
Helmholtz-Zentrum Dresden-Rossendorf | Bautzner Landstr. 400 | 01328 Dresden, Germany | www.hzdr.de

The Helmholtz-Zentrum Dresden-Rossendorf (HZDR) conducts research in the sectors energy, health, and matter. It focuses its research on the following topics:
• How can energy and resources be used efficiently, safely, and sustainably?
• How can malignant tumors be visualized and characterized more precisely and treated effectively?
• How do matter and materials behave in strong fields and in the smallest dimensions?
The HZDR has been a member of the Helmholtz Association, Germany’s largest research organization, since 2011. It has four locations (Dresden, Leipzig, Freiberg, Grenoble) and employs about 1,100 people – approximately 500 of whom are scientists, including 150 doctoral candidates.

Weitere Informationen:

https://www.hzdr.de/presse/bioremediation

Dr. Christine Bohnet | Helmholtz-Zentrum Dresden-Rossendorf

More articles from Life Sciences:

nachricht Small but ver­sat­ile; key play­ers in the mar­ine ni­tro­gen cycle can util­ize cy­anate and urea
10.12.2018 | Max-Planck-Institut für Marine Mikrobiologie

nachricht Carnegie Mellon researchers probe hydrogen bonds using new technique
10.12.2018 | Carnegie Mellon 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: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

Im Focus: The force of the vacuum

Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.

The vacuum is not empty. It may sound like magic to laypeople but it has occupied physicists since the birth of quantum mechanics.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Small but ver­sat­ile; key play­ers in the mar­ine ni­tro­gen cycle can util­ize cy­anate and urea

10.12.2018 | Life Sciences

New method gives microscope a boost in resolution

10.12.2018 | Physics and Astronomy

Carnegie Mellon researchers probe hydrogen bonds using new technique

10.12.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>