Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

On the Tip

10.12.2003


USC researcher Liman investigates taste buds -- made up of bundles of 50 to 100 taste cells -- to better understand how animals detect sweet, bitter and umami flavors.

Photo/Rudy Moro


Put a caramel in your mouth and your taste buds detect the sugary substance, instantly sending a message to the brain, which interprets the signal - sweet!

Trying to figure out what happens in the split-second between eating something and recognizing its sweet or bitter flavor - between detecting a taste and a signal reaching the brain - led USC neuroscientist Emily Liman to take a closer look inside the cells in the taste buds.

Her findings reveal new details about how the sense of taste works.



And calcium, said Liman, plays a key role in the detection of tastes by taste cells in the tongue.

The research by Liman, an assistant professor of biological sciences in the USC College of Letters, Arts & Sciences, and graduate student Dan Liu will be published in the Proceedings of the National Academy of Sciences this month. The paper also offers a molecular model of how taste cells reset so they are ready to detect new tastes.

The study appeared online Dec. 1 in the journal’s early edition.

Until recently, scientists have known little about how taste works on a cellular or molecular level. Just four years ago, scientists officially added a unique taste, called umami, to the list of the better known: sweet, bitter, salty and sour.

Umami receptors are sensitive to the amino acid glutamate, which most think serves as a marker for protein-rich foods.

Glutamate also is the main ingredient in the commonly used flavor additive MSG (monosodium glutamate), which may explain the additive’s appeal.

Taste research has attracted the attention of researchers like Liman who are interested in unraveling how cellular signaling works.

Food and drug industry scientists also are very interested in understanding the molecular details of taste, especially bitter and sweet, Liman said.

“It’s important to know how taste works and to identify the molecules involved,” she said. “These molecules can be targets for designing chemicals that activate taste - for example, a better artificial sweetener - or that block taste, such as an additive that could be used to block bitter tastes.”

In the study, Liman and Liu looked closely at a protein necessary for detecting sweet, bitter and umami tastes.

Without the protein, called TRPM5, mice can’t discern between the flavors.

Once activated, the protein appears to play a key role in the taste-signaling pathway, somehow sending a message to the brain about what’s been tasted..

Liman, who has investigated similar issues relating to the sense of smell and pheromone detection, studied how this protein worked in an experimental cell system.

She found that the protein acts like a gated bridge on the cell’s membrane, connecting the inside and outside of the cell. The gate opened when the researchers added calcium ions.

In general, proteins like TRPM5 are considered good potential drug targets because their position on the cell surface makes them more accessible than proteins inside the cell.

In other experiments, Liman and Liu figured out that the protein TRPM5 closes as it undergoes desensitization to taste.

Desensitization is what allows a person to adapt to a strong taste or smell over time, perhaps barely noticing it after a while.

The researchers also found that the TRPM5 protein gate opens up again through an interaction with another cellular molecule called PIP2.

Liman cautioned that her team has yet to show conclusively that calcium is responsible for the initiation of the signal to the brain.

To prove this, she will have to see whether her laboratory studies apply to taste cells in living animals, experiments she hopes to start soon.

Eva Emerson | USC
Further information:
http://www.usc.edu/uscnews/story.php?id=9616

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>