Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Summer Heat Too Hot for You? What Is Comfortable?

31.07.2008
Extreme heat or cold is not only uncomfortable, it can be deadly—causing proteins to unravel and malfunction.

For many years now, scientists have understood the molecular mechanisms that enable animals to sense dangerous temperatures; such as extremely high temperatures that directly trigger heat sensor proteins known as TRP channels. However, much more poorly understood is how animals sense very small temperature differences in the comfortable range, and choose their favorite temperature.

Reporting this week at Nature Neuroscience, Johns Hopkins researchers now have discovered that the fruit fly uses TRPA1 to sense single degree changes in the comfortable range. However, rather than sensing temperature changes directly, TRPA1 functions in the last step of a multistep process that uses many of the same proteins that function in vision. Just as the early events involved in vision allow animals to adapt to different light intensities, the multistep process involved in temperature detection potentially allows animals to adapt to different temperatures in the comfortable range as well.

“It’s an exciting discovery, yet in a lot of ways it just makes a lot of sense,” says Craig Montell, Ph.D., a professor of biological chemistry and member of Johns Hopkins’ new Center for Sensory Biology. “You clearly don’t want to hang around or adapt to a temperature that could kill you, but on the other hand, if you can't find your favorite temperature, it is OK to adapt to another comfortable temperature.”

... more about:
»Montell »Multistep »TRP »TRPA1 »adapt »differences »larvae »sense
Montell and his team use fruit flies as their experimental model because it is easy to perform genetic manipulations on these animals. Temperatures colder than 16 degrees Celsius (61 degrees Fahrenheit) or warmer than 26 degrees C (79 degrees F) are known to trigger an avoidance response. Fruit fly maggots (larvae), explains Montell, prefer 18 degrees C (64 degrees F), but are comfortable at temperatures ranging from 18 to 24 degrees C (64 to 75

degrees F).

To first figure out if the larvae could even sense small temperature differences in the 18 to 24 degree “comfort zone,” Montell’s team set up a preference test that consisted of a plastic plate where one half of the plate was kept at 18 degrees and the other half at a different temperature, from 19 to 24 degrees. After 15 minutes, they counted the number of larvae on each side of the plate.

“It turns out these larvae can discriminate one degree differences—they prefer 18 over 19 degrees” says Montell. “The question then was: How do they do this?”

Since TRP channels are known to open in response to changes in temperature, Montell’s team then tested flies containing mutations in 12 fruit fly TRP genes to see if any were required for the ability to sense temperature changes within the comfort zone.

Eleven of the 12 TRP mutants still preferred 18 degrees to other temperatures in this range. Only the TRPA1 mutant larvae showed no temperature preference, suggesting to the researchers that only TRPA1 is required for comfort zone temperature sensing.

The known “thermoTRPs” all open directly in response to changes in temperature. TRP proteins also are involved in other types of sensory biology, including vision, explains Montell. But rather than being directly triggered by light, a different light sensor molecule activates the TRP vision protein indirectly. Since TRPA1 is not turned on by changes in temperature in the comfortable range, Montell’s team reasoned that perhaps, in this range, TRPA1 might be triggered indirectly through a series of steps similar to those that function in vision.

The team then tested flies with mutations disrupting proteins known to work with TRP proteins required for fly vision and found that they, too, were unable to discern temperature differences in the 18 to 24 C range.

Thus, Montell and co-workers have found a new way that TRP channels function in thermosensation, and this “is quite reminiscent of how we detect light.”

“We think it’s important for adaptation; if a fly finds itself at 34 degrees (93 degrees F), it should never try to adapt to that temperature, because it will die,” says Montell. “But flies living at 22 degrees could adapt to this environment because, while this temperature isn’t their optimal choice, it still isn’t deleterious.” The multistep vision-like strategy for sensing changes in temperature could also be well suited for amplifying very small differences in temperature, such as 18 and 19 degrees C. This strategy could allow animals to respond to one degree changes that might otherwise not be possible through a process involving just one protein.

The team’s work raises the possibility that similar multistep processes may allow mammals to sense small changes in internal body temperature.

The research was funded by the National Eye Institute and the National Institute of General Medical Sciences.

Authors on the paper are Young Kwon, Hye-Seok Shim, Xiaoyue Wang and Montell, all of Hopkins.

Audrey Huang | Newswise Science News
Further information:
http://www.jhmi.edu
http://www.nature.com/neuro/index.html
http://biolchem.bs.jhmi.edu/members/facultydetail.asp?PersonID=674

Further reports about: Montell Multistep TRP TRPA1 adapt differences larvae sense

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>