Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Red pandas reveal an unexpected (artificial) sweet tooth

17.04.2009
Preference for artificial sweeteners previously thought to exist only in Old World primates

Researchers from the Monell Center report that the red panda is the first non-primate mammal to display a liking for the artificial sweetener aspartame. This unexpected affinity for an artificial sweetener may reflect structural variation in the red panda's sweet taste receptor.

The findings may shed light on how taste preferences and diet choice are shaped by molecular differences in taste receptors.

"The red panda's unique taste receptor gives us a tool to broaden our understanding of how we detect sweet taste," said the paper's senior author, Joseph G. Brand, PhD, a biophysicist at Monell. "Greater insight into why we like artificial sweeteners could eventually lead to the development of more acceptable sugar substitutes, potentially benefiting diabetics and other individuals on sugar-restricted diets."

Many species like sweet-tasting foods, but there are some exceptions. In an earlier study, Brand and Monell comparative geneticist Xia Li, PhD, reported that cats – both domestic and wild – can not taste sweets due to a defect in one of the genes that codes for the sweet taste receptor.

The current research extended those findings by relating sweet preferences to genetic analyses of sweet receptor structure in six related species. Like the cat, each of the species tested -- red panda, ferret, genet, meerkat, mongoose, and lion -- belongs to the Order Carnivora.

The species, although closely related, vary widely with regard to the types of foods they eat. For example, lions, like other cats, are obligate carnivores, meaning that they eat almost exclusively meat. Meerkrats are mainly insectivores, while red pandas are primarily herbivores that almost exclusively eat bamboo leaves and shoots.

By studying the structure and function of the sweet receptor gene across species and how this relates to differences in taste preferences and diet selection, the researchers seek to provide a framework to increase understanding of individual differences in human taste function, food choice and nutritional health.

"The taste world of every species, and even every individual, is unique, defined in part by the structure of their taste receptors," said Li. "We need to know more about these differences and how they influence our diet."

In the study, published online in the Journal of Heredity, preferences for six natural sugars and six artificial sweeteners were tested in a zoo setting. For each sweet molecule, the animal was given access to both the sweet solution and water for 24 hours. The animal was said to prefer the sweet solution when it drank much more sweet fluid than water.

DNA samples from each species were used to examine the structure of the sweet receptor gene Tas1r2, which codes for the T1R2 sweet taste receptor. T1R2 is one of two taste receptors that join together to recognize sweetness.

The sweet taste receptors contain binding sites for a variety of natural sugars and artificial sweeteners. However, species vary regarding which sites they possess, due to subtle differences in receptor structure.

As expected from the previous findings, the lion did not prefer any of the sweet solutions. This could be explained by its defective Tas1r2 gene, which prevents the lion from expressing a functional sweet taste receptor. With no sweet receptor, the lion is unable to detect – or prefer – sweet-tasting compounds.

Each of the remaining species preferred at least some of the natural sugars. Consistent with having a functional sweet receptor, Tas1r2 genes from these species did not show the defect found in lion and other cats.

Because only primates were believed to be able to taste aspartame, the researchers predicted that none of the Carnivore species tested would show a preference for the artificial sweeteners.

This indeed was the case for five of the species. However, the sixth species – the red panda – drank large amounts of the artificial sweeteners aspartame, neotame, and sucralose.

Seeking to explain this unexpected behavior, the researchers compared Tas1r2 genes from various species that can and cannot taste aspartame. They were surprised to find no consistent differences between aspartame tasters and nontasters.

However, the genetic analysis did reveal that the red panda's sweet receptor has a unique structure that is different from any of the other species examined.

"This may explain why the red panda is able to taste artificial sweeteners," said Li, who is the paper's lead author. "What we don't know is why this particular animal has this unusual ability. Perhaps the red panda's unique sweet receptor evolved to allow this animal to detect some compound in its natural food that has a similar structure to these sweeteners."

The findings suggest that the receptor mechanisms for sweet taste are more complex than previously suspected. "This is the essence of molecular science," remarked Brand, "Asking a behavioral question and getting a molecular answer."

Future studies will explore how protein structure of taste receptor genes predicts stimulus binding and ultimately provide insight into how variations in taste receptor genes affect taste perception, food choice and nutritional status.

Taste tests for the red panda and other animals in the study were conducted at two zoos in Switzerland by Dieter Glaser, PhD, from the University of Zurich. Also contributing to the study were Monell scientists Gary Beauchamp and Weihua Li, along with Warren Johnson and Stephen O'Brien from the National Cancer Institute.

The Monell Chemical Senses Center is an independent nonprofit basic research institute based in Philadelphia, Pennsylvania. Monell advances scientific understanding of the mechanisms and functions of taste and smell to benefit human health and well-being. Using an interdisciplinary approach, scientists collaborate in the programmatic areas of sensation and perception; neuroscience and molecular biology; environmental and occupational health; nutrition and appetite; health and well-being; development, aging and regeneration; and chemical ecology and communication.

Leslie Stein | EurekAlert!
Further information:
http://www.monell.org

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

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 pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>