Navigation Links
Psst! Coffee drinkers: Fruit flies have something to tell you about caffeine

In their hunt for genes and proteins that explain how animals discern bitter from sweet, a team of Johns Hopkins researchers began by testing whether mutant fruit flies prefer eating sugar over sugar laced with caffeine. Using a simple behavioral test, the researchers discovered that a single protein missing from the fly-equivalent of our taste buds caused them to ignore caffeine's taste and consume the caffeine as if it were not there.

"No, you won't see jittery Drosophila flitting past your bananas to slurp your morning java anytime soon," says Craig Montell, Ph.D., a professor of biological chemistry in the Institute of Basic Biomedical Sciences at Hopkins. "The bottom line is that our mutant flies willingly drink caffeine-laced liquids and foods because they can't taste its bitterness -- their taste receptor cells don't detect it."

The Hopkins flies, genetically mutated to lack a certain taste receptor protein, have been the focus of studies to sort out how animals taste and why we like the taste of some things but are turned off by the taste of others.

By color-coding sweet and bitter substances eaten by fruit flies and examining the coloring that shows up in their translucent bellies, the Hopkins team hoped to learn whether flies missing a specific "taste-receptor" protein changed their taste preferences.

"Normally," Montell explains, "when given the choice between sweet and bitter substances, flies avoid caffeine and other bitter-tasting chemicals. But flies missing this particular taste-receptor protein, called Gr66a, consume caffeine because their taste-receptor cells don't fire in response to it."

The discovery, which is the first ever example of a protein required for both caffeine tasting and caffeine-induced behavior, will be published Sept. 19 in Current Biology.

For the study, Montell and his colleagues kept 50 fruit flies away from food overnight and for breakfast gave the starved flies 90 minutes to eat as much as they wanted of either or both of two concoctions: a blue-colored mixture of sugar and agar and a red-colored mixture of caffeine, sugar and agar. The researchers then flipped the flies onto their backs and looked at the color of their bellies to see what they ate - blue indicating a preference for eating sugar, red indicating a preference for bitter caffeine, and purple indicating no preference.

Flies missing the critical taste receptor protein Gr66a consumed the bitter caffeine solution to the same extent as the sugar-only solution. Montell and colleagues conclude that Gr66a is crucial for the normal caffeine avoidance behavior and without it, flies are seemingly indifferent to the bitter taste.

The researchers went on to examine whether this indifference to bitter was due to the taste nerves on the fly's "tongue" or some malfunction in the fly's brain. Chemical stimulants trigger taste receptor cells to send an electrical current to the brain where the information is processed and often leads to a change in behavior, such as the decision to eat or avoid.

With fine tools, the research team recorded electrical currents in those cells known to contain the Gr66a caffeine taste receptor in the fly's equivalent of the taste buds - dubbed the taste bristles.

Applying sugar to the taste bristles of normal flies, or to mutant flies missing the Gr66a protein, causes the neurons to produce electrical current "spikes" at a frequency of about 20 spikes per second. Other bitter compounds like quinine generated electrical current spikes at about the same frequency in the mutants.

Only flies missing the Gr66a taste receptor protein were unable to generate any current spikes when given caffeine. "This is a clear demonstration that Gr66a is functioning in the taste receptor cells and is not a 'general sensor' for bitter compounds, but is required more specifically for the caffeine response," says Montell.

"This ind icates that flies have different receptors for the response to other types of bitter compounds," he says.

"We also tested whether the flies avoided the related bitter compounds found in tea and cocoa -- chocolate -- and found that Gr66a also is required for the response to the compound in tea, but not for the one in chocolate," he says.

Fruit flies often are used as experimental organisms because they grow quickly and are easy to manipulate genetically. Now that Montell and his colleagues have a mutant fly that is unable to taste caffeine, they hope to further examine the other genes and molecules involved in the caffeine response and better understand the biochemistry behind caffeine-induced behavior in other organisms, namely humans.


'"/>

Source:Johns Hopkins Medical Institutions


Related biology news :

1. Coffee makes us more likely to say yes
2. X-Ray Beams And Fruit Fly Flight Simulator Aid Scientists View Of Muscle Power
3. Fruit fly studies open new window on cancer research
4. Fruit fly research set to revolutionize study of birth defects
5. How Fruitflies Know Its Time for Lunch
6. Fruit flys beating heart helps identify human heart disease genes
7. Fruit fly reveals a potential connection between dementia and cancer
8. Fruit fly dating game provides clues to our reproductive prowess
9. Fruit fly aggression studies have relevance to humans, animals
10. Fruit fly study identifies gene mutation that regulates sensitivity to alcohol
11. Fruit flies and global warming -- Some like it hot
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/27/2017)... , March 27, 2017  Catholic Health ... and Management Systems Society (HIMSS) Analytics for achieving ... Adoption Model sm . In addition, CHS previously ... U.S. hospitals using an electronic medical record (EMR). ... its high level of EMR usage in an ...
(Date:3/23/2017)... DUBLIN , Mar. 23, 2017 Research ... Anti-Theft System Market Analysis & Trends - Industry Forecast to 2025" ... ... to grow at a CAGR of around 8.8% over the next ... This industry report analyzes the market estimates and forecasts for all ...
(Date:3/20/2017)... 2017 At this year,s CeBIT Chancellor Dr. ... DERMALOG. The Chancellor came to the DERMALOG stand together with the Japanese ... CeBIT partner country. At the largest German biometrics company the two government ... and iris recognition as well as DERMALOGĀ“s multi-biometrics system.   ... ...
Breaking Biology News(10 mins):
(Date:4/27/2017)... ... April 27, 2017 , ... ... internist, who will review how testing for 1,25-Dihydroxyvitamin D can enhance clinical practice. ... 25-OH-vitamin D and 1,25 dihydroxyvitamin D. , Dr. Gregory Plotnikoff, senior consultant with ...
(Date:4/27/2017)... , April 27, 2017  Pendant Biosciences, Inc. ... innovative surface modification and drug delivery technologies, today announced ... Innovation, JLABS @ Toronto . ... Officer of Pendant Biosciences, noted, "We are excited to ... community, and are honored to be the ...
(Date:4/26/2017)... Centennial, CO (PRWEB) , ... April 25, 2017 , ... ... test offerings were added to its extensive test menu: Nucleic Acid Testing (NAT) ... that time, LABS was only able to offer NAT screening for blood donors under ...
(Date:4/25/2017)... ... ... As part of the Stago EdVantage Virtual University Virtual Event, ... order to illuminate this clinical problem for people unfamiliar with the topic. , DIC ... high degree of morbidity and mortality. DIC is a confusing disorder from both diagnostic ...
Breaking Biology Technology: