Tuesday, February 23, 2010

UF RESEARCHERS FIND GENES THAT TUNE FLOWER FRAGRANCES

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Shakespeare famously wrote, “That which we call a rose by any other name would smell as sweet.” With all due respect to the Bard, University of Florida researchers may have to disagree: no matter what you call a flower, its scent can be changed.

A team at UF’s Institute of Food and Agricultural Sciences has uncovered some of the genes that control the complex mixture of chemicals that comprise a flower’s scent, opening new ways of “turning up” and “tuning” a flower’s aromatic compounds to produce desired fragrances.

“For a long time, breeders have mostly focused on how flowers look, their size, color and how long blooms last,” said David Clark, a professor of environmental horticulture. “But scent has gotten left behind. Go to a florist and try to smell the flowers. You probably won’t get what you expect.”

Over the years, Clark says, breeders have selected flowering plants that produce bigger, more attractive flowers with long vase lives; but in doing so, they may have been inadvertently selecting plants that were willing to devote less to producing fragrance.

That may change. For example, a customer may someday be able to walk into a florist and select from scented or unscented varieties of the same flower.

In work published in the January issue of The Plant Journal and the February issue of Phytochemistry, the researchers describe how various genes in petunias help regulate the amount of the 13 major aromatic compounds in that flower’s fragrance.

The work will help researchers control the levels of these compounds, adjusting a flower’s fragrance while also producing more or less of it.

In the papers, the researchers also describe some of the more fundamental aspects of how flowers produce scent. For example, they observed that the scents are largely manufactured in the petunia flower’s petals, and that scent production is activated when the flower opens.

The studies are part of an ongoing effort to isolate the chain reaction responsible for producing scent, so that fragrances can be modified without interfering with other flower qualities, said Thomas Colquhoun, a UF environmental horticulture researcher and first author on both papers.

For more than a decade, Clark and his colleagues have combed through more than 8,000 petunia genes. The search has yielded some interesting finds.

For example, the gene that produces the compound that gives rose oil its distinctive scent also makes tomatoes taste good.

By manipulating this gene, UF researchers led by horticulture professor Harry Klee have been able to create tomatoes with more flavor. Klee, Clark and colleagues are now working with plant breeders and taste specialists to prepare the tomato for the marketplace. Better smelling roses are also in the pipeline.

“The taste of food, the smell of a flower — these are things that enrich our lives in ways we don’t fully understand yet,” Clark said. “Learning how plants interact with us and their environment brings us closer to truly appreciating what the natural world has to offer.”

(Photo: Tyler Jones, UF/IFAS)

University of Florida

SILVER NANOPARTICLES MAY ONE DAY BE KEY TO DEVICES THAT KEEP HEARTS BEATING STRONG AND STEADY

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Diamonds and gold may make some hearts flutter on Valentine's Day, but in a University at Buffalo laboratory, silver nanoparticles are being designed to do just the opposite.

The nanoparticles are part of a new family of materials being created in the laboratory of SUNY Distinguished Professor and Greatbatch Professor of Advanced Power Sources Esther Takeuchi, PhD, who developed the lithium/silver vanadium oxide battery. The battery was a major factor in bringing implantable cardiac defibrillators (ICDs) into production in the late 1980s. ICDs shock the heart into a normal rhythm when it goes into fibrillation.

Twenty years later, with more than 300,000 of these units being implanted every year, the majority of them are powered by the battery system developed and improved by Takeuchi and her team. For that work she has earned more than 140 patents, believed to be more than any other woman in the United States. Last fall, she was one of four recipients honored in a White House ceremony with the National Medal of Technology and Innovation.

ICD batteries, in general, now last five to seven years. But she and her husband and co-investigator, SUNY Distinguished Teaching Professor of Chemistry Kenneth Takeuchi, PhD, and Amy Marschilok, PhD, UB research assistant professor of chemistry, are exploring even-better battery systems, by fine-tuning bimetallic materials at the atomic level.

Their research investigating feasibility for ICD use is funded by the National Institutes of Health, while their investigation of new, bimetallic systems is funded by the U.S. Department of Energy.

So far, their results show that they can make their materials 15,000 times more conductive upon initial battery use due to in-situ (that is, in the original material) generation of metallic silver nanoparticles. Their new approach to material design will allow development of higher-power, longer-life batteries than was previously possible.

These and other improvements are boosting interest in battery materials and the revolutionary devices that they may make possible.

"We may be heading toward a time when we can make batteries so tiny that they -- and the devices they power -- can simply be injected into the body," Takeuchi says.

Right now, her team is exploring how to boost the stability of the new materials they are designing for ICDs. The materials will be tested over weeks and months in laboratory ovens that mimic body temperature of 37 degrees Celsius.

"What's really exciting about this concept is that we are tuning the material at the atomic level," says Takeuchi. "So the change in its conductivity and performance is inherent to the material. We didn't add supplements to achieve that, we did it by changing the active material directly."

She explains that new and improved batteries for biomedical applications could, in a practical way, revolutionize treatments for some of the most persistent diseases by making feasible devices that would be implanted in the brain to treat stroke and mental illness, in the spine to treat chronic pain or in the vagal nerve system to treat migraines, Alzheimer's disease, anxiety, even obesity.

And even though batteries are an historic technology, they are far from mature, Takeuchi notes. This spring, she is teaching the energy storage course in UB's School of Engineering and Applied Sciences and the class is filled to capacity. "I've never seen interest in batteries as high as it is now," she says.

(Photo: U. Buffalo)

University at Buffalo

MOTHER BATS EXPERT AT SAVING ENERGY

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In order to regulate their body temperature as efficiently as possible, wild female bats switch between two strategies depending on both the ambient temperature and their reproductive status. During pregnancy and lactation, they profit energetically from clustering when temperatures drop. Once they have finished lactating, they use torpor to a greater extent, to slow their metabolic rate and drop their body temperature right down so that they expend as little energy as possible.

These findings by Iris Pretzlaff, from the University of Hamburg in Germany, and colleagues, were just published online in Springer’s journal Naturwissenschaften – The Science of Nature.

When energy demands are high, such as during pregnancy and lactation, female bats need to efficiently regulate their body temperature to minimize energy expenditure. In bats, energy expenditure is influenced by environmental conditions, such as ambient temperature, as well as by social thermoregulation – clustering to minimize heat and energy loss. Torpor, another common temperature regulation strategy, has disadvantages for reproductive females, such as delayed offspring development and compromised milk production.

Pretzlaff and team investigated, for the first time in the wild, the thermoregulation strategies used by communally roosting Bechstein’s bats during different periods of their reproductive cycle – pre-lactation, lactation, and post-lactation. They collected data from two maternity colonies roosting in deciduous forests near Würzburg in Germany, predominantly in bat boxes. The authors measured ambient temperature over those three periods as well as the bats’ metabolic rate by using respirometry (measuring the rate of oxygen consumption).

They found that the bats’ metabolic rate was strongly influenced by the ambient temperature. However, by roosting in groups (social thermoregulation), the bats were able to regulate their body temperature more effectively, despite changes in daily ambient temperature.

The bats also used torpor to minimize energy expenditure, particularly post-lactation - more than twice as often than during the other two periods. This suggests that they predominantly use torpor once they can afford to do so without compromising offspring development and milk production. They also formed much smaller groups post-lactation when temperatures were lower because roosting in smaller groups reduces the risk of disturbances by conspecifics. This resulted in longer torpor bouts and therefore longer periods of energy saving.

The authors conclude: “We were able to demonstrate on wild Bechstein’s bats, during different reproductive periods, the significance of behavioral and physiological flexibility for optimal thermoregulatory behavior. Our study also highlights the importance of field studies, where the animals can use their behavioural and physiological repertoire, which is often not possible under the generally more controlled regimes in laboratory studies.”

Springer Science+Business Media

STUDY FINDS SURPRISING NEW BRANCHES ON ARTHROPOD FAMILY TREE

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In a scientific and technological tour de force that was nearly a decade in the making, a team of scientists from Duke University, the University of Maryland and the Natural History Museum of Los Angeles County have compared genetic sequences from 75 different species to draw a new family tree that includes every major arthropod lineage. Some of the relationships are so surprising that new names had to be coined for five newly-discovered groupings.

The work, which was supported by the National Science Foundation, appears early online Wednesday in the journal Nature.

A big surprise to tumble out of the new tree is that the closest living relatives of insects include a small and obscure group of creatures called remipedes that were only discovered in the late 1970s living in a watery cave in the Bahamas. With linear bodies like centipedes, simple legs and no eyes, it was thought that this small group -- now placed with cephalocarids in the newly-named Xenocarida or "strange shrimp" -- would be found at the base of the crustacean family tree.

Now, after analyzing 62 shared genetic sequences across all the arthropods, the researchers are putting the strange shrimp together with the six-legged insects, Hexapoda, to form a new group they dubbed Miracrustacea, or "surprising crustaceans." As a "sister clade" to hexapods, the Xenocarida likely represent the sort of creature that came onto land to start the spectacular flowering of the insect lineage, said Cliff Cunningham, a professor of biology at Duke who led the study.

Triops, a 2-inch crustacean that looks like a cross between a horseshoe crab and a mayfly, had also been thought of as an early crustacean, but it too was shown to have a relatively modern origin in the new analysis, Cunningham said.

"Taxonomists have been arguing about these things for decades, and people kept coming at this with one data set after another," Cunningham said. This latest study has created a fuller picture of the arthropod family tree by using more species and more genes, he said.

Beginning in 2001, Jeffrey Shultz, an associate professor of entomology at Maryland, led the efforts to figure out which species needed to be sequenced for a robust comparison, and then to round up suitable specimens of each. The study included nematodes, scorpions, dragonflies, barnacles, copepods and centipedes.

Remipedes, one of the two species of Xenocarida in the study, had to be fetched from partially submerged limestone caves in the Yucatan Peninsula and preserved just so. Bitty creatures called mystacocarids that live between grains of sand were captured by the Natural History Museum's Regina Wetzer, using a microscope on a Massachusetts beach.

Once assembled, the 75 species were then stripped down to their DNA for a painstaking search to find genetic sequences that would appear across all arthropods, enabling statistical comparisons.

The lab of Jerome Regier at Maryland's Center for Biosystems Research combed through 2,500 different combinations of PCR primers to find 62 protein-coding gene sequences that could be compared across all 75 species. Regier was an early proponent of using protein coding genes to sort out the arthropod tree, while most other researchers were using relatively less complex analyses from the DNA found in ribosomes and mitochondria.

The researchers ran four different statistical approaches, including two new ones invented at Maryland, "and they all came up with the same answer," Cunningham said. Earlier studies had not used as many genes or as many species, making this study about four times larger than anything done previously.

The spiders, ticks and scorpions of the subgroup Chelicerata are shown to have split from the line leading to insects and crustaceans even before the millipedes and centipedes of the subphylum Myriapoda. Most recent molecular studies had grouped these arachnids in Chelicerata together with millipedes and centipedes of the Myriapoda. But the new analysis puts millipedes and centipedes together with crustaceans and insects in a group taxonomists had long ago named Mandibulata.

"The only thing people thought they knew before molecular data was available was that the Myriapods were with the insects," Shultz said. But that turned out to be wrong. Even the grouping Crustacea is no longer correct, since it includes the six-legged insects.

Within the insect group Hexapoda, the good news for taxonomists who have grouped insects according to body shape and features is that they were pretty much on the mark, Shultz added.

There are still many holes that need to be filled in, Cunningham said, but at least the shape of the tree seems right. "Now the developmental biologists can really piece things together."

(Photo: Simon Richards)

Duke University

RESEARCHERS FIND HOW BRAIN HEARS THE SOUND OF SILENCE

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A team of University of Oregon researchers have isolated an independent processing channel of synapses inside the brain's auditory cortex that deals specifically with shutting off sound processing at appropriate times. Such regulation is vital for hearing and for understanding speech.

The discovery, detailed in the Feb. 11 issue of the journal Neuron, goes against a long-held assumption that the signaling of a sound's appearance and its subsequent disappearance are both handled by the same pathway. The new finding, which supports an emerging theory that a separate set of synapses is responsible, could lead to new, distinctly targeted therapies such as improved hearing devices, said Michael Wehr, a professor of psychology and member of the UO Institute of Neuroscience.

"It looks like there is a whole separate channel that goes all the way from the ear up to the brain that is specialized to process sound offsets," Wehr said. The two channels finally come together in a brain region called the auditory cortex, situated in the temporal lobe.

To do the research, Wehr and two UO undergraduate students -- lead author Ben Scholl, now a graduate student at the Oregon Health and Science University in Portland, and Xiang Gao -- monitored the activity of neurons and their connecting synapses as rats were exposed to millisecond bursts of tones, looking at the responses to both the start and end of a sound. They tested varying lengths and frequencies of sounds in a series of experiments.

It became clear, the researchers found, that one set of synapses responded "very strongly at the onset of sounds," but a different set of synapses responded to the sudden disappearance of sounds. There was no overlap of the two responding sets, the researchers noted. The end of one sound did not affect the response to a new sound, thus reinforcing the idea of separate processing channels.

The UO team also noted that responses to the end of a sound involved different frequency tuning, duration and amplitude than those involved in processing the start of a sound, findings that agree with a trend cited in at least three other studies in the last decade.

"Being able to perceive when sound stops is very important for speech processing," Wehr said. "One of the really hard problems in speech is finding the boundaries between the different parts of words. It is really not well understood how the brain does that."

As an example, he noted the difficulty some people have when they are at a noisy cocktail party and are trying to follow one conversation amid competing background noises. "We think that we've discovered brain mechanisms that are important in finding the necessary boundaries between words that help to allow for successful speech recognition and hearing," he said.

The research -- funded in part by the UO's Robert and Beverly Lewis Center for Neuroimaging Fund -- aims to provide a general understanding of how areas of the brain function. The new findings, Wehr said, could also prove useful in working with children who have deficits in speech and learning, as well as in the design of hearing aids and cochlear implants. He also noted that people with dyslexia have problems defining the boundaries of sounds in speech, and tapping these processing areas in therapy could boost reading skills.

(Photo: U. Oregon)

University of Oregon

SELECTIVE BRAIN DAMAGE MODULATES HUMAN SPIRITUALITY

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New research provides fascinating insight into brain changes that might underlie alterations in spiritual and religious attitudes. The study, published by Cell Press in the February 11 issue of the journal Neuron, explores the neural basis of spirituality by studying patients before and after surgery to remove a brain tumor.

Although it is well established that all behaviors and experiences, spiritual or otherwise, must originate in the brain, true empirical exploration of the neural underpinnings of spirituality has been challenging. However, recent advances in neuroscience have started to make the complex mental processes associated with religion and spirituality more accessible.

"Neuroimaging studies have linked activity within a large network in the brain that connects the frontal, parietal, and temporal cortexes with spiritual experiences, but information on the causative link between such a network and spirituality is lacking," explains lead study author, Dr. Cosimo Urgesi from the University of Udine in Italy.

Dr. Urgesi and colleagues were interested in making a direct link between brain activity and spirituality. They focused specifically on the personality trait called self-transcendence (ST), which is thought to be a measure of spiritual feeling, thinking, and behaviors in humans. ST reflects a decreased sense of self and an ability to identify one's self as an integral part of the universe as a whole.

The researchers combined analysis of ST scores obtained from brain tumor patients before and after they had surgery to remove their tumor, with advanced techniques for mapping the exact location of the brain lesions after surgery. "This approach allowed us to explore the possible changes of ST induced by specific brain lesions and the causative role played by frontal, temporal, and parietal structures in supporting interindividual differences in ST," says researcher Dr. Franco Fabbro from the University of Udine.

The group found that selective damage to the left and right posterior parietal regions induced a specific increase in ST. "Our symptom-lesion mapping study is the first demonstration of a causative link between brain functioning and ST," offers Dr. Urgesi. "Damage to posterior parietal areas induced unusually fast changes of a stable personality dimension related to transcendental self-referential awareness. Thus, dysfunctional parietal neural activity may underpin altered spiritual and religious attitudes and behaviors."

These results may even lead to new strategies for treating some forms of mental illness. "If a stable personality trait like ST can undergo fast changes as a consequence of brain lesions, it would indicate that at least some personality dimensions may be modified by influencing neural activity in specific areas," suggests Dr. Salvatore M. Aglioti from Sapienza University of Rome. "Perhaps novel approaches aimed at modulating neural activity might ultimately pave the way to new treatments of personality disorders."

Cell Press

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