Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Revolutionary nanotechnology illuminates brain cells at work

31.05.2005


Until now it has been impossible to accurately measure the levels of important chemicals in living brain cells in real time and at the level of a single cell. Scientists at the Carnegie Institution’s Department of Plant Biology and Stanford University are the first to overcome this obstacle by successfully applying genetic nanotechnology using molecular sensors to view changes in brain chemical levels. The sensors alter their 3-dimensional form upon binding with the chemical, which is then visible via a process known as fluorescence resonance energy transfer, or FRET. In a new study, the nanosensors were introduced into nerve cells to measure the release of the neurotransmitter glutamate--the major brain chemical that increases nerve-cell activity in mammalian brains. It is involved in everything from learning and memory to mood and perception. Too much glutamate is believed to contribute to conditions such as Alzheimer’s and Parkinson’s disease. The research is published in the May 30-June 3 on-line early edition of the Proceedings of the National Academy of Sciences.



"The fluorescent imaging technique allows us to see living cells do their jobs live and in color," explained Sakiko Okumoto, lead author of the study at Carnegie. "Understanding when and how glutamate is produced, secreted, reabsorbed, and metabolized in individual brain cells, in real time, will help researchers better understand disease processes and construct new drugs."

"FRET is like two musical tuning forks, which have the same tone," Okumoto continued. "If you excite one, it gives a characteristic tone. If you bring the second fork close to the first one, it will also start to give you a tone even though they do not touch. This is resonance energy transfer."


FRET is used to track the form of proteins that specifically bind metabolites such as sugars and amino acids. A protein of interest is genetically fused with two differently colored tags made from variants of the jellyfish Green Fluorescent Protein (GFP). The colored tags are placed at each end of the molecule making a "biosensor." When the substance of interest binds to the sensor, the sensor backbone becomes reoriented, and the reorientation can be detected. Since light is a vibration, the same response occurs with two fluorescent dyes that have overlapping, but slightly different colors–in this case cyan and yellow versions of GFP. The cyan is excited and, if the distance between the colored proteins changes, more or less energy is transferred to the yellow protein. In this study, the cyan and yellow proteins behave as if they move away from one another when the sensor recognizes glutamate. Thus, there is more cyan and less yellow light than in the absence of glutamate. The sensors are encoded by genes and genetic ZIP codes can be used to target the sensors to any location in the cell and to its surface.

"We used a protein called ybeJ from the common bacterium E. coli. We first predicted the structure of this protein, and then placed the two fluorophores at specific positions on the binding protein," commented co-author Loren Looger. "After fusion to the fluorescent proteins, we placed the sensor on the surface of rat hippocampal cells. The hippocampus is the part of the brain that is involved with emotional reactions, and it helps store learned information in memory. When neurons are activated, they secrete glutamate, and we could see this activity under the microscope by watching the color change. We stimulated the neurons and watched them secrete glutamate in response. We also saw the removal of the glutamate as the neurons returned to normal ready to fire again."

"This is a tremendously exciting technology," remarked Wolf Frommer, leader of the FRET team at Carnegie. "I’m anxious to see what we can learn about the vast complexities of the brain over the coming years, such as the role of glial cells in the process of glutamate removal from the synaptic cleft. It’s fascinating to see a tool that we are using in plant biology open new areas in neuroscience."

Wolf Frommer | EurekAlert!
Further information:
http://www.carnegieinstitution.org

More articles from Life Sciences:

nachricht Immune Defense Without Collateral Damage
23.01.2017 | Universität Basel

nachricht The interactome of infected neural cells reveals new therapeutic targets for Zika
23.01.2017 | D'Or Institute for Research and Education

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>