Peer into the deep recesses of an ant colony and you'll discover an extremely well organized community with thousands of workers quietly going about their jobs. Some dig nests while others gather food or tend the young. Remarkably, every chore is done without supervision or direction, and some workers even switch jobs to meet the ever-changing needs of the colony. How does an insect with a brain the size of a poppy seed decide to carry out a particular task? The answer, says a team of Stanford University biologists, has less to do with brainpower than with the ant`s extraordinary sense of smell. Writing in the journal Nature, the Stanford scientists found that, when a parade of patroller ants returns to the nest, their distinctive body odor cues other workers to go out and forage for food. This new insight into the behavior of social insects is the latest discovery to emerge from a 20-year field study of red harvester ants (Pogonomyrmex barbatus) in the southern Arizona desert - a project designed and led by Deborah M. Gordon, an associate professor of biological sciences at Stanford. "The question is, how does a worker know what to do?" said Gordon, coauthor of the May 1 Nature study. "There's nobody in charge, there's nobody telling it what to do."

Keyword: Chemical Senses (Smell & Taste); Animal Communication
Link ID: 3756 - Posted: 05.01.2003

DURHAM, N.C. -- Researchers have discovered that some iridescent butterflies use the polarization of light refracted from their intricate prismatic scales as a mating signal -- the first time that light polarization has been identified as a mating signal for any terrestrial animal species. The discovery was reported in an article in the May 1 Nature by Duke University biologists Alison Sweeney and Sönke Johnson, and Christopher Jiggins of the University of Edinburgh in Scotland. The research was sponsored by the National Science Foundation. The initial mystery that attracted her, said graduate student Sweeney, was why butterflies possessed such intricate iridescent structures on their wings.

Keyword: Sexual Behavior
Link ID: 3755 - Posted: 06.24.2010

Voltage-dependent channel structure reveals masterpiece responsible for all nerve, muscle activity Imagine evaluating sculptures without the privilege of sight. The task of analyzing visual art would shrink to partial, indirect descriptions that fail in conveying the object's true character. Some aspects of the work of art and its surroundings would still be accessible, but ultimately the analysis would be unsatisfying, inaccurate and misleading. The masterpiece is a voltage-dependent potassium ion channel, the first published picture of which illustrates the cover of Nature's May 1 edition, revealed by MacKinnon and his rainmaking group of biophysicist-crystallographers. Inside, Nature features two articles, co-authored by Vanessa Ruta, Alice Lee, Jiayun Chen, Brian Chait, D. Phil., and Martine Cadene, Ph.D. that correct the proposals of scientists who lacked the definitive picture showing a potassium channel with charge-triggered "paddles" responsible for opening and closing a passage for potassium ions to freely move through.

Keyword: Miscellaneous
Link ID: 3754 - Posted: 05.01.2003

Until now, doctors could only measure the physical spread of Alzheimer’s disease by examining the brains of deceased patients after it was too late to help them. But with a new brain scanning technique, now they can see the disease progressing in living patients, which will allow them to pinpoint where and how fast the disease is spreading, and reveal whether drugs and vaccines combat the brain damage that Alzheimer’s causes. Neuroscientists from the University of California Los Angeles (UCLA) and the University of Queensland in Australia used a new imaging analysis technique to track the spread of Alzheimer’s-related cell death in living patients. They detected changes in brain scans created using magnetic resonance imaging (MRI), and created the first 3-D, time-lapse video map showing the spread of Alzheimer’s disease. “This is the first technique to actually watch the physical spread of Alzheimer’s in the [living] brain,” says Paul Thompson, assistant professor of neurology at the David Geffen School of Medicine at UCLA, the study’s chief investigator. “You can use this to look at drug effects, whether they are helping a patient. You can use it for early diagnosis, to see if a person actually has Alzheimer’s. You can also use it to tell if a patient is aging healthily.” © ScienCentral, 2000-2003

Keyword: Alzheimers; Brain imaging
Link ID: 3753 - Posted: 06.24.2010

NewScientist.com news service Fish are capable of experiencing pain. This is the conclusion of researchers who observed rainbow trout behaviour after the animals were given injections that would be painful to people. Other scientists reject their interpretation, but the study could still be used by anti-angling campaigners. The argument over whether fishing is a "blood sport" in the same vein as fox hunting and hare coursing has hinged on whether fish feel pain in a similar way to animals. If they do not, as most researchers currently believe, then the animal welfare argument against angling largely falls apart. Lynne Sneddon at the Roslin Institute, near Edinburgh, Scotland, and her colleagues, took measurements from individual neurons in anaesthetised fish while they poked the fish's heads and applied acid and heat. © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch; Animal Rights
Link ID: 3752 - Posted: 06.24.2010

Most dog owners have experienced that moment when the soulful eyes of their companions look to their empty dog dishes, up into their humans' eyes, and back to the empty dog dish. That propensity to look at humans' faces may be the key difference between dogs and their wolf ancestors. Most researchers agree that dogs diverged from wolves and took up residence with humans over 10,000 years ago. But how the split occurred and how much dogs differ from wolves isn't known. Copyright © 2003 by the American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 3751 - Posted: 06.24.2010

Potential targets to slow disease The main pathological signature of Alzheimer disease (AD), which causes progressive memory loss in its victims, is plaques in the brain. Currently, massive research efforts are geared toward eliminating these plaques. In a new study published in the April issue of the Journal of Neuroscience, researchers at the Alzheimer Research Laboratory at Case Western Reserve University School of Medicine report finding the molecules that play a critical role in making the brain think it is under attack from these plaques, triggering immune cells in the brain. The inflammation mediated by these cells speeds up the debilitating consequences of AD. With the discovery of these molecules, researchers say new therapies could be devised aimed at blocking their action to slow down progression of AD. From previous studies looking at people with rheumatoid arthritis, scientists know that people on non-steroidal, anti-inflammatory drugs, such as ibuprofen, have a lower incidence of AD. Gary Landreth, Ph.D., professor of neurosciences at CWRU, and his team, are searching for why this happens.

Keyword: Alzheimers
Link ID: 3750 - Posted: 04.30.2003

By LAURIE TARKAN Without so much as a nick to her scalp, Cheryl Hogarth had major brain surgery on a tumor that had grown to nearly the size of a Ping-Pong ball deep within her brain. Ms. Hogarth, who at 37 was told her malignant tumor was inoperable and given a prognosis of six months to live, went under the Gamma Knife, no-knife surgery that blasts its target with hundreds of high-intensity radiation beams in a single session. There was none of the cutting, bleeding, general anesthesia, ear-to-ear scar or long recovery associated with traditional craniotomy. She went home that evening. Two years after the surgery, Ms. Hogarth, a Sacramento mother of two, is a survivor. She takes chemotherapy to supplement the treatment, and the tumor has not grown. "I now have hope that I will be here to watch my children grow up," she said. Copyright 2003 The New York Times Company

Keyword: Miscellaneous
Link ID: 3749 - Posted: 04.29.2003

By LES LINE In a rite of spring nearly as old as the Nebraska sandhills, greater prairie chickens and sharp-tailed grouse gather before dawn on their respective dancing grounds at Valentine National Wildlife Refuge in the north-central part of the state. While females watch, the males lower their heads, raise their tails, spread their wings, inflate colorful air sacs on their necks and stamp their feet while making hollow cooing or moaning sounds. The basic purpose of this elaborate display is to attract a mate. Indeed, the dancing ground, or lek, is the avian equivalent of a singles bar, said Dr. Robert Gibson, a behavioral ecologist and professor of biological sciences at the University of Nebraska. But Dr. Gibson, who has studied lekking behavior around the world, is convinced there is more going on. Copyright 2003 The New York Times Company

Keyword: Sexual Behavior
Link ID: 3748 - Posted: 04.29.2003

Migratory birds not only get to see the world. A new study finds that these globetrotters also have better long-term memories than stay-at-home relatives. The extra brain power could help ensure that the birds don’t get lost on their travels. Birds flying long distances use celestial cues, their sense of smell, and Earth’s magnetic field as rough guides to navigation. As they near their final destination, however, they switch strategies. They look for landmarks such as bushes and trees they have memorized during previous trips. That's how the birds return to the same breeding, wintering, and stopover sites year after year. Anatomical studies suggested that migrants do a lot of learning en route. Garden warblers, for example, return to central Europe from their first trip to Africa with a bigger hippocampus, a region of the brain involved in learning spatial information. Nonmigrating Sardinian warblers, on the other hand, show no such change. But direct evidence that life on the move makes birds remember better was missing. Copyright © 2003 by the American Association for the Advancement of Science.

Keyword: Animal Migration; Learning & Memory
Link ID: 3747 - Posted: 06.24.2010

Preliminary genome comparison points to primate individuality. HELEN PEARSON By studying chimpanzees, scientists are honing their genetic view of humanity, researchers told this week's meeting of the Human Genome Organisation in Cancun, Mexico. A group presented the first detailed comparison between a large chunk of human DNA and the equivalent from our closest relative. The genetic make-up of chimpanzee chromosome 22 is hot off the press, having just been sequenced, and matches human chromosome 21. The data call for some revision of the estimated genetic similarity between us and our closest relatives. Previously, human and chimp genetic sequences were quoted as being nearly 99% identical, with a difference of only a few DNA's letters. In fact, the similarity may be as low as 94-95%, says Todd Taylor of the RIKEN Genomic Sciences Center in Yokohama, Japan. © Nature News Service / Macmillan Magazines Ltd 2003

Keyword: Evolution
Link ID: 3746 - Posted: 06.24.2010

Charcot-Marie-Tooth and Distal Spinal Muscular Atrophy Gene May Shed Light on Carpel Tunnel Syndrome and Lou Gehrig's Disease Bethesda, Maryland — Scientists at the National Human Genome Research Institute (NHGRI) and at the National Institute of Neurological Disorders and Stroke (NINDS) have identified the gene responsible for two related, inherited neurological disorders, and have, for the first time, directly implicated this gene and its enzyme product in a human genetic disease. The discovery supports further investigation of this gene family for additional neurological disease genes, research that may shed light on a range of disorders, including carpel tunnel syndrome, which affects the hands and the wrists, and the fatal degenerative disease amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease. NHGRI and NINDS scientists, working together at the National Institutes of Health (NIH), found the gene responsible for Charcot-Marie-Tooth (CMT) disease type 2D and distal spinal muscular atrophy (dSMA) type V. The gene, called GARS — the glycyl tRNA synthetase gene — is located on chromosome 7 and encodes, or provides the instructions to make, one of the aminoacyl tRNA synthetases, a family of enzymes vital to the cell's ability to build proteins.

Keyword: Genes & Behavior; ALS-Lou Gehrig's Disease
Link ID: 3745 - Posted: 06.24.2010

Creation of signposts detected in the first non-human species Humans are not alone in creating ‘signposts’ to help them find their way, according to new research published in the open access journal BMC Ecology. Wood mice, say scientists, move objects from their environment around using them as portable signposts whilst they explore. The finding is significant as this is the first time such sophisticated behaviour has been identified in any mammal except humans. According to the authors, “This is precisely how a human might tackle the problem of searching efficiently in a homogeneous environment – for example by placing a cane in the ground as a reference point from which to search for a set of keys dropped on a lawn.” Quick, effective navigation is vital for the wood mouse. Home-ranges are vast in comparison to the mammal’s size and consist of uniform areas, like ploughed fields, without obvious landmarks. These environments are not the same all year round, and harvest time drastically changes the availability of any ‘fixed’ landmarks, food supplies and hiding places.

Keyword: Animal Migration; Intelligence
Link ID: 3744 - Posted: 06.24.2010

'Smartness' about social life is different from smartness about SAT scores What do the brain, ovaries and nose have in common? According to new research from The Rockefeller University, these three organs help orchestrate the complex behavior called social recognition in female mice through the interaction of four genes. The findings, reported in the April 29 issue of PNAS Early Edition, help explain social interactions among female animals, and may shed light on social phobias and disorders in humans. The researchers, led by Rockefeller professor Donald Pfaff, Ph.D., show that strains of female mice that lack the genes for oxytocin and the estrogen receptors alpha and beta fail to recognize normal female mice after repeated instances when the normal animal was placed in the same space. The gene "knockout" mice also failed to investigate a new "intruder mouse" under circumstances where a genetically normal mouse would do so.

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 3743 - Posted: 04.29.2003

A new mouse study suggests fasting every other day can help fend off diabetes and protect brain neurons as well as or better than either vigorous exercise or caloric restriction. The findings also suggest that reduced meal frequency can produce these beneficial effects even if the animals gorged when they did eat, according the investigators at the National Institute on Aging (NIA). "The implication of the new findings on the beneficial effects of regular fasting in laboratory animals is that their health may actually improve if the frequency of their meals is reduced," says Mark Mattson, Ph.D., chief of the NIA's Laboratory of Neurosciences. "However, this finding, while intriguing, will need to be explored further. Clearly, more research is needed before we can determine the full impact that meal-skipping may have on health." In the study*, published in the Proceedings of the National Academy of Sciences Online Early Edition the week of April 28, 2003, Dr. Mattson and his colleagues found mice that were fasted every other day but were allowed to eat unlimited amounts on intervening days had lower blood glucose and insulin levels than either a control group, which was allowed to feed freely, or a calorically restricted group, which was fed 30 percent fewer calories daily than the control group. Despite fasting, the meal-skipping mice tended to gorge when provided food so they did not eat fewer calories than the control group. This finding in mice suggests that meal-skipping improves glucose metabolism and may provide protection against diabetes, Dr. Mattson says.

Keyword: Obesity
Link ID: 3742 - Posted: 04.29.2003

STANFORD, Calif. - Scientists have finally laid hands on the first member of a recalcitrant group of proteins called the Wnts two decades after their discovery. Important regulators of animal development, these proteins were suspected to have a role in keeping stem cells in their youthful, undifferentiated state - a suspicion that has proven correct, according to research carried out in two laboratories at Stanford University Medical Center. The ability to isolate Wnt proteins could help researchers grow some types of stem cells for use in bone marrow transplants or other therapies. The gene coding for a protein usually reveals clues about how that protein will react in the lab and how best to isolate it from other molecules. The Wnts are unusual, however, because the way they behave in the lab differs from what the gene suggests. Roeland Nusse, PhD, professor of developmental biology at the School of Medicine and one of the first to isolate a Wnt (pronounced "wint") gene, reports how his lab members overcame these hurdles in the April 27 advance online edition of the journal Nature. "We found that the protein is modified, explaining why it has been difficult to isolate," said Nusse, who is also an investigator at the Howard Hughes Medical Institute. Although the protein's structure suggests it should dissolve easily in water, Karl Willert, PhD, a postdoctoral fellow in Nusse's lab, found that an attached fat molecule makes the protein shun water and prefer the company of detergents instead.

Keyword: Stem Cells
Link ID: 3741 - Posted: 04.29.2003

By EMILY EAKIN Thomas W. Laqueur is a scholarly gumshoe with a specialty in sex. His last book, "Making Sex: Body and Gender From the Greeks to Freud" (1990), was a highly original investigation of a tantalizing mystery he had stumbled on in the archives: Why did female orgasm, long considered essential to conception, all but disappear from the historical record during the Enlightenment? Now, in "Solitary Sex: A Cultural History of Masturbation," Mr. Laqueur, a professor of history at the University of California at Berkeley, tackles another enigma from the annals of sexual history: Why did masturbation, an activity regarded with benign indifference for millennia, provoke sweeping moral and medical panic around 1700? Mr. Laqueur's preoccupations are hardly the kind destined to endear him to the cultural right. In particular, his latest tome — which features a floating, naked woman wearing an expression of glazed-eyed ecstasy on its cover and a couple dozen graphic illustrations inside — seems designed to inflame critics convinced that the academy is populated by tenured radicals bent on selling students a morally suspect and intellectually trivial bill of goods. Copyright 2003 The New York Times Company

Keyword: Sexual Behavior
Link ID: 3740 - Posted: 06.24.2010

By Dr David Whitehouse BBC News Online science editor Australopithecus fossils from caves in South Africa may have been buried about 4 million years ago, as much as 1 million years earlier than previously thought. Australopithecus is an important hominid - human ancestor - that demonstrates the transition from ape-like features to human ones. Its kind were first discovered in East Africa and lived about four million years ago. Researchers used a technique that measured the decay of radioactive isotopes formed when the fossil was on the surface, but which declined when it was buried. The new dates make the South African fossils as old as similar specimens found in East Africa, forcing a revision of how far scientists believe Australopithecus ranged. The fossils were from the caves and quarries at Sterkfontein, 50 km northwest of Johannesburg, that are some of the richest hominid fossil sites in the world. About 500 specimens have been recovered there since the 1936 discovery of the first adult Australopithecus. (C) BBC

Keyword: Evolution
Link ID: 3739 - Posted: 04.27.2003

By DIRK OLIN Last month, a quartet of academics published ''What's Wrong With the Rorschach?'' -- attacking a test administered to more than a million people worldwide each year. According to recent surveys by the American Psychological Association, 82 percent of its members ''occasionally'' and 43 percent ''frequently'' use the test, in which subjects speculate about five colored and five black-and-white inkblots. Test-givers in turn interpret the answers to diagnose mental illness, predict violent behavior and reveal suppressed trauma. Their conclusions are applied to everything from child-custody disputes to parole reviews. According to James M. Wood, an associate professor of psychology at the University of Texas at El Paso and one author of the book, tarot cards would work almost as well. Wood and his colleagues level basic criticisms against the inkblot test's foundations. They say it lacks accurate norms to serve as benchmarks for comparing healthy and sick patients. Reliability is also at issue, because many scores are determined by test-givers' subjective interpretations. And last, they contend that virtually none of the scores are scientifically valid, because they neither measure what they claim nor can be consistently correlated with other tests or diagnoses. The Rorschachers simply harbor a ''romantic'' devotion to the test's efficacy, Wood says, one based on ''an uncritical, even gullible, acceptance of ridiculous claims that the Rorschach is like a medical test, a sort of brain scan.'' In the few years since the critics first began making their arguments, a sometimes visceral academic firefight has broken out. Rorschachers have hired a lobbyist, and one of the test's historic champions has been joined by younger acolytes in churning out hotly disputed studies in its defense. Copyright 2003 The New York Times Company

Keyword: Miscellaneous
Link ID: 3738 - Posted: 04.27.2003

NewScientist.com news service A mother's poor diet around the time of conception can cause premature birth, according to new research in sheep. If the same is true for humans, and there is some evidence that it is, bad nutrition could account for some of the 40 per cent of premature births that remain unexplained in developed countries. Premature birth is by far the most common cause of death in newborn babies, and its incidence in western societies has increased in the past decade. Previous studies have shown that reduced maternal nutrition - in women with anorexia, for example - can cause lower birthweight in babies born after a full-length pregnancy. © Copyright Reed Business Information Ltd.

Keyword: Development of the Brain
Link ID: 3737 - Posted: 06.24.2010