Bitter love and heart

Bitter taste receptors found on human hearts

TNN | May 5, 2015, 08.15 PM IST

READ MORE taste receptors|Smell and taste receptors

MELBOURNE: Smell and taste receptors normally found in the nose and mouth can also be present on the human heart, scientists have found.

University of Queensland researchers found that around 12 taste receptors, particularly those that respond to bitter compounds, were expressed in human hearts.

"This is quite remarkable, as the human genome only has 25 of these bitter taste receptors, and we wanted to find out why half of them were located in the heart," said Professor Walter Thomas, from The School of Biomedical Sciences.

"When we activated one of the taste receptors with a specific chemical that we all taste as bitter, the contractile function of the heart was almost completely inhibited.

"While the underlying physiology behind this phenomenon remains unclear, this is now a major area of ongoing investigation," Thomas said.

The research team's primary focus is on how the heart grows normally as well as abnormally in disease.

"After hypertension or a heart attack, the heart frequently undergoes compensatory growth in order to maintain the circulation of blood around the body," Thomas said.

"During laboratory tests, we were looking at all the genes that are regulated in the heart in this growth phase.

"We found the rodent heart cells we were working with contained smell and taste receptors, which are normally considered to be only present in the nose and mouth," he said.

"Using heart tissue from humans undergoing heart surgery, such as valve replacement and coronary arterial bypass, we replicated the rodent laboratory experiments and found taste receptors were also present in the human heart," he said.

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Tiny beetle’s explosive spray mechanism revealed by X-rays

Mumbai Mirror | May 2, 2015, 03.28 AM IST

Many beetles secrete foulsmelling or bad-tasting chemicals from their abdomens to ward off predators, but bombardier beetles take it a step further. When threatened, they combine chemicals in an explosive chemical reaction chamber in their abdomen to simultaneously synthesise, heat and propel their defensive load as a boiling hot spray, complete with "gun smoke." They can even precisely aim the nozzle at the attacker.

Wendy Moore, an assistant professor in the Department of Entomology at the University of Arizona, just published a paper together with a multidisciplinary team of scientists that not only reveals the beetle's firing apparatus in never-before-seen detail, but also solves a long-standing mystery of how the animals achieve their insane rapid-fire capabilities.

"Understanding how these beetles produce - and survive - repetitive explosions could provide new design principles for technologies such as blast mitigation and propulsion," said the lead authors of the study about the motivation for their research.

The study was led by Eric Arndt and Christine Ortiz from the Massachusetts Institute of Technology.

Using enzymes that digest away muscle and fat, Moore could clean the reaction chamber and examine it with optical microscopy in detail. While studying the shape of the reaction chamber, she noticed that some regions of the chamber wall were thin and not as strong as others, and that one region near the mixing valve looked particularly thin. She predicted that this thin cuticle would be displaced by the force of the reactions in such a way that it would impinge upon the valve, temporarily shutting off the flow of reactants. To investigate this hypothesis, the team decided to directly observe the internal dynamics of spray pulsation in live beetles.

The team took hundreds of the species Brachinus elongatulus beetles to co-author Wah-Keat Lee, he helped set up an experiment to obtain X-ray video of beetles firing their smoking rounds at up to 2,000 frames per second. They team set up the beetles in a tightly sealed room next to the synchrotron - a particle accelerator that can produce intense X-rays.

The researchers observed how the beetles regulate the ultrafast micropulses, something that had never been achieved before. It turns out the pulses are generated in a passive way, not through an active process involving muscle contraction, as had been hypothesised before. As the chemicals pass through a valve into the reaction chamber, they mix with enzymes and explosively liberate oxygen gas, water vapor and heat, propelling a hot, noxious spray down the nozzle and out the exit pore. Each explosion inside the chamber forces a highly elastic region of the chamber wall to expand and impinge on the valve that separates the two chambers, temporarily cutting off the flow of reactants and resulting in a pulsed delivery.

While it is still not completely clear why it might be beneficial to the beetle to have a pulsed delivery, Moore suspects that dividing the spray into very short, rapid pulses allows the beetle to sustain the energy of the blast and its small body size at the same time. MM

New test can predict cancer up to 13 years before it hits

Henry Austin,The Independent | May 1, 2015, 06.40 PM IST

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READ MORE telomeres|cancer prediction

New test can predict cancer up to 13 years before it hits

The discovery of tiny but significant changes taking place in the body more than a decade before cancer was diagnosed helped researchers at Harvard and Northwestern University make the breakthrough. (The Independent)

Scientists have developed a new test that can predict with 100 per cent accuracy whether someone will develop cancer up to 13 years in the future.

The discovery of tiny but significant changes taking place in the body more than a decade before cancer was diagnosed helped researchers at Harvard and Northwestern University make the breakthrough.

Their research, published in the online journal Ebiomedicine, found protective caps on the ends of chromosomes, which prevent DNA damage were more worn down those who went on to develop cancer.

Known as telomeres, these were much shorter than they should have been and continued to get shorter until around four years before the cancer developed, when they suddenly stopped shrinking.

"Because we saw a strong relationship in the pattern across a wide variety of cancers, with the right testing these procedures could be used eventually to diagnose a wide variety of cancers," said Dr Lifang Hou, the lead study author, told The Telegraph.

"Understanding this pattern of telomere growth may mean it can be a predictive biomarker for cancer....We found cancer has hijacked the telomere shortening in order to flourish in the body."