Monday, February 1, 2010

GENETIC ANALYSIS GIVES HOPE THAT EXTINCT TORTOISE SPECIES MAY LIVE AGAIN

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Thanks to genetic data gleaned from the bones found in a several museum collections, an international team of researchers led by scientists from Yale believes it may be possible to resurrect a tortoise species hunted to extinction by whalers visiting the Galapagos Islands during the early 19th century, before Charles Darwin made his famous visit.

A genetic analysis of 156 tortoises living in captivity and the DNA taken from remains of specimens of the now-extinct Chelonoidis elephantopus revealed that nine are descendents of the vanished species, which once made its home on Floreana Island in the Galapagos. Over a few generations, a selective breeding program among these tortoises should be able to revive the C. elephantopus species, said Adalgisa Caccone, senior research scientist in the department of ecology and evolutionary biology at Yale and senior author of the piece published this week in the online journal PLoS ONE.

“Theoretically, we can rescue a species that has gone extinct,’’ Caccone said. “Our lab calls it the Lazurus project.”

In 2007, Caccone and others discovered genetic relatives to “Lonesome George” the last known survivor of another species of Galapagos tortoise and an icon of the conservation movement. The team believes that the similar genetic hybrids living in captivity on the Galapagos were descendents of tortoises that were taken by whalers as future meals but then thrown overboard to make room for the more lucrative cargo of whale blubber. These tortoises then swam to nearby islands and mated with natives there. Floreana’s flat topography made it a popular spot for whalers to stop and snatch tortoises for meals, leading to the extinction of C. elephantopus.

The comparison of genetic data from remains in museums to data banks with DNA sequences of living tortoises made it possible to identify relatives of extinct animals, Caccone said. However, it will take at least four generations of selective breeding – about 100 years - to bring a genetically identical member of C. elephantopus “back to life.”

“We won’t be around to see it, but it can be done,” she said.

(Photo: Yale U.)

Yale University

MOVING THROUGH TIME

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Although we can’t technically travel through time (yet), when we think of the past or the future we engage in a sort of mental time travel. This uniquely human ability to psychologically travel through time arguably sets us apart from other species. Researchers have recently looked at how mental time travel is represented in the sensorimotor systems that regulate human movement. It turns out our perceptions of space and time are tightly coupled.

University of Aberdeen psychological scientists Lynden Miles, Louise Nind and Neil Macrae conducted a study to measure this in the lab. They fitted participants with a motion sensor while they imagined either future or past events. The researchers found that thinking about past or future events can literally move us: Engaging in mental time travel (a.k.a. chronesthesia) resulted in physical movements corresponding to the metaphorical direction of time. Those who thought of the past swayed backward while those who thought of the future moved forward.

These findings reported online in Psychological Science, a journal of the Association for Psychological Science, suggest that chronesthesia may be grounded in processes that link spatial and temporal metaphors (e.g., future= forward, past= backward) to our systems of perception and action. “The embodiment of time and space yields an overt behavioral marker of an otherwise invisible mental operation,” explains Miles and colleagues.

The Association for Psychological Science

CAN MODERN-DAY PLANTS TRACE THEIR NEW ZEALAND ANCESTRY?

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One hundred million years ago the earth looked very different from how it does today. Continents were joining and breaking apart, dinosaurs were roaming the earth, and flowering plants were becoming more widespread.

The southern hemisphere supercontinent known as Gondwana formed around 180-200 mya during the breakup of Pangaea and then began to split apart about 167 mya. As scientists reconstruct the history of these land masses and life during this period, many questions arise. For example, is the current flora of New Zealand derived from plants that grew on Gondwana before its breakup, or derived from plants that more recently dispersed to New Zealand?

Recent research published in the January issue of the American Journal of Botany (http://www.amjbot.org/cgi/content/full/97/1/59) by Dr. Gregory Jordan of the University of Tasmania and a team of researchers from New Zealand and Austria explore the answer to these questions based on observations of two macrofossils from the Late Oligocene/Early Miocene time period (28-15 mya) in New Zealand.

Based on observations and evolutionary analyses, Jordan and colleagues identified the two fossils as members of the epacrid subfamily of the plant family Ericaceae, known as the heath family. Their data demonstrate that by the Early Miocene, New Zealand was home to at least two different lineages of epacrids. Past examples of Ericaceae fossil pollen in New Zealand have suggested that the family's presence in New Zealand dates back to the Late Cretaceous period (66.5-99.6 mya), but these recent evolutionary analyses suggest a much younger history for most groups of plants in that region.

"The epacrids encapsulate many of the problems that have fascinated botanists in the southern hemisphere," Jordan said. "How important was Gondwana? Why do we have so many sclerophylls? How do sclerophylls work? We have only just started to work these plants out."

Cyathodophyllum novae-zelandiae is the first unambiguous, pre-Pleistocene macrofossil from the tribe Styphelieae identified, and it appears to be from a lineage of plants that is now extinct. Richeaphyllum waimumuensis was identified as a member of the tribe Richeeae, but the scientists are unsure about whether it is from an extant or extinct lineage.

Although pollen from the fossil record has demonstrated that members of the Ericaceae plant family have been present in New Zealand since the Late Cretaceous, this research demonstrates that the presence of ancient fossils from a plant family may not provide evidence regarding the history of modern members of the family, providing a cautionary note to other researchers trying to reconstruct the history of a group of plants. Discovery of new macrofossils and/or detailed examinations of fossil pollen combined with evolutionary analyses may help to answer questions of whether the ancestors of current plants coexisted with dinosaurs in New Zealand.

"Delving into the details of plant fossils can give you surprises," Jordan said. "The fossil record of pollen could be read to say that this group of plants is a relic from the breakup of Gondwana—but by combining the leaf fossils and evidence from molecular biology, it looks like exactly the opposite is true."

American Journal of Botany

AN ELECTRIFYING ADVANCE TOWARD TOMORROW'S POWER SUITS

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Could powering an iPod or cell phone become as easy as plugging it into your tee shirt or jeans, and then recharging the clothing overnight? Scientists in California are reporting an advance in that direction with an easier way of changing ordinary cotton and polyester into "conductive energy textiles" — e-Textiles that double as a rechargeable battery. Their report on the research appears in ACS' Nano Letters, a monthly journal.

"Wearable electronics represent a developing new class of materials with an array of novel functionalities, such as flexibility, stretchability, and lightweight, which allow for many applications and designs previously impossible with traditional electronics technology," Yi Cui and colleagues note. "High-performance sportswear, wearable displays, new classes of portable power, and embedded health monitoring systems are examples of these novel applications."

The report describes a new process for making E-textiles that uses "ink" made from single-walled carbon nanotubes — electrically conductive carbon fibers barely 1/50,000 the width of a human hair. When applied to cotton and polyester fabrics, the ink produced e-Textiles with an excellent ability to store electricity. The fabrics retained flexibility and stretchability of regular cotton and polyester, and kept their new e-properties under conditions that simulated repeated laundering.

(Photo: American Chemical Society)

American Chemical Society

OLDER BRAINS MAKE GOOD USE OF 'USELESS' INFORMATION

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A new study has found promising evidence that the older brain's weakened ability to filter out irrelevant information may actually give aging adults a memory advantage over their younger counterparts.

A long line of research has already shown that aging is associated with a decreased ability to tune out irrelevant information. Now scientists at Baycrest's world-renowned Rotman Research Institute have demonstrated that when older adults "hyper-encode" extraneous information – and they typically do this without even knowing they're doing it – they have the unique ability to "hyper-bind" the information; essentially tie it to other information that is appearing at the same time.

The study, which appears online in the journal Psychological Science, was led by Karen Campbell, a PhD student in psychology at the University of Toronto, with supervision from Rotman senior scientist Dr. Lynn Hasher, a leading authority in attention and inhibitory functioning in younger and older adults.

"We found that older brains are not only less likely to suppress irrelevant information than younger brains, but they can link the relevant and irrelevant pieces of information together and implicitly transfer this knowledge to subsequent memory tasks," said Campbell.

In the study, 24 younger adults (17 – 29 years) and 24 older adults (60 – 73 years) participated in two computer-based memory tasks that were separated by a 10-minute break. In the first task, they were shown a series of pictures that were overlapped by irrelevant words (e.g. picture of a bird and the word "jump"). They were told to ignore the words and concentrate on the pictures only. Every time they saw the same picture twice in a row, they were to press the space bar. After completing this task and following a 10-minute break, they were tested on a "paired memory task" which essentially challenged them to recall how the pictures and words were paired together from the first task. They were shown three kinds of paired pictures – preserved pairs (pictures with overlap words that they saw in the first task), disrupted pairs (pictures they saw in the first task but with different overlap words) and new pairs (new pictures and new words they hadn't seen before).

The older adults showed a 30% advantage over younger adults in their memory for the preserved pairs (the irrelevant words that went with the pictures in the first task) relative to the new pairs.

"This could be a silver lining to aging and distraction," said Dr. Hasher, senior scientist on the study. "Older adults with reduced attentional regulation seem to display greater knowledge of seemingly extraneous co-occurrences in the environment than younger adults. As this type of knowledge is thought to play a critical role in real world decision- making, older adults may be the wiser decision-makers compared to younger adults because they have picked up so much more information."

Baycrest

BARROW RESEARCHER REPORTS THAT SLOW BREATHING REDUCES PAIN

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Research performed by a scientist at Barrow Neurological Institute at St. Joseph's Hospital and Medical Center has shown that controlled breathing at a slowed rate can significantly reduce feelings of pain.

Chronic pain sufferers, specifically fibromyalgia (FM) patients, also reported less pain while breathing slowly, unless they were overwhelmed by negative feelings, sadness or depression.

The research was led by Arthur (Bud) Craig, PhD, at Barrow, and was done in collaboration with investigators in the Department of Psychology at Arizona State University. It was published recently in PAIN, the refereed journal of the International Association for the Study of Pain (IASP). The findings offer an explanation for prior reports that mindful Zen meditation has beneficial effects on pain and that yogic breathing exercises can reduce feelings of depression. These results also underline the role that a person's positive or negative attitude can have on their feelings of pain.

The study involved two groups of women aged 45 to 65. One group was composed of women previously diagnosed with fibromyalgia, and the other group was "healthy controls."

During the trial, participants were subjected to moderately painful heat pulses on their palms. The heat pulses were administered while they were breathing at normal rates and when participants reduced their breathing rates by 50 percent. After each heat pulse, participants were asked to report their feelings three ways: how strong the pain was (pain intensity), how uncomfortable it was (pain unpleasantness) and how their mood varied (affect).

The researchers analyzed the participants' ratings of pain intensity and unpleasantness and found an overall reduction in reported pain when the healthy control participants were paced to breathe slowly. However, fibromyalgia patients benefited from slow breathing only if they reported positive affect.

Other studies have shown that depression is a hallmark of fibromyalgia and that the connection between pain and emotion is particularly evident in people diagnosed with the fibromyalgia syndrome.

Results of the Barrow study showed that FM patients as a whole did not show a lessening of pain when breathing slowly, but those FM patients with strong positive affect as a trait (meaning it is an aspect of their personality, not simply the situation) did show some improvement. "This fits with the idea that FM patients in general have low positive affect, or energy reserves. Those who do have some positive energy left in their "mental battery" can use it to reduce pain by breathing slowly, just like healthy normals," says Dr. Craig.

St. Joseph's Hospital

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