In combination with earlier evidence, the findings suggest the so-called muscarinic acetylcholine pathway might play a conserved role in animals’ starvation response, the researchers said. The new findings might ultimately yield insights into the connection between eating disorders and an abnormal response to hunger or starvation, they suggest.
"In the nematode worm C. elegans, starvation causes a variety of changes in development, longevity, and behavior," said Young-jai You of the University of Texas Southwestern Medical Center. One such behavioral change involves alterations to the animals’ main feeding organ, the pharynx.
The worms eat by "pumping" bacteria in via relaxation and contraction of their pharyngeal muscle--an activity controlled by their internal feeding status. However, the signal responsible for changes in pumping rate had yet to be found.
The research team now reports that starvation activates the enzyme MAPK in the pharyngeal muscles of C. elegans through a muscarinic acetylcholine receptor. Mutations and drugs that prevented any step of the signal from muscarinic receptor to MAPK blocked the effects of starvation on the feeding muscle, they found. Furthermore, an excess of MAPK in normal worms mimicked the effect of starvation on the muscle.
"In mammals, muscarinic acetylcholine receptors regulate heart muscle and smooth muscle of the [digestive] tract, and MAPK signaling activation downstream of muscarinic acetylcholine receptors has been widely noted," wrote Kaveh Ashrafi in a Preview. "Moreover, there are intriguing but conflicting reports on the role of the receptors in growth rate and body weight of rodents.
"It is therefore plausible that molecular mechanisms that mediate starvation responses of C. elegans pharyngeal muscle are conserved across phylogeny," Ashrafi said.
The findings might help to unravel the factors underlying eating disorders, the researchers said.
"Despite the prevalence of feeding disorders from obesity to anorexia, the identity and mechanism of action of starvation signals are largely unknown," You’s team added. "Our study of starvation sensitivity of gpb-2 mutants and the downstream signaling pathway in feeding muscles suggests that feeding disorders may result from inappropriate behavioral responses to starvation signals."
Heidi Hardman | EurekAlert!
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21.11.2017 | Allen Institute
Nanoparticles help with malaria diagnosis – new rapid test in development
21.11.2017 | Fraunhofer-Institut für Silicatforschung ISC
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
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The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
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Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
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