have

Increased risk of osteoporosis associated with gene that one in five people have

About nineteen percent of people have a genetic variation that may increase susceptibility to osteoporosis, a new study reveals. Researchers at Washington University School of Medicine in St. Louis demonstrated that in women the variant gene speeds up the breakdown of estrogen and is associated with low density in the bones of the hip. The study will be reported in the February issue of t...

Migratory songbirds have a specialized night-vision brain area

Neurobiologists have discovered a specialized night-vision brain area in night-migratory songbirds. They believe the area might enable the birds to navigate by the stars, and to visually detect the earth's magnetic field through photoreceptor molecules, whose light-sensitivity is modulated by the field. The researchers published their findings May 23, 2005, in the early online edition of t...

Red delicious, Northern Spy apples have most antioxidants, chemists find

Some apples might do a better job of keeping the doctor away than others, according to Canadian researchers who analyzed eight popular varieties of the fruit. Red Delicious, Northern Spy and Ida Red, they say, pack a greater wallop of disease-fighting antioxidants than other apples studied. The researchers, led by Rong Tsao, Ph.D., of Agriculture and Agri-Food Canada in Guelph, Ontario, a...

Findings have implications for tracking disease, drugs at the molecular level

Researchers in the laboratory of Boston College Chemistry Professor John T. Fourkas have demonstrated that gold particles comparable in size to a molecule can be induced to emit light so strongly that it is readily possible to observe a single nanoparticle. Fourkas, in collaboration with postdoctoral researcher Richard Farrer and BC undergraduates Francis Butterfield and Vincent Chen, coaxed the...

Certain fish have a special mating preference

A biologist at Washington University in St. Louis has shown that for some fish species, females prefer males with larger sexual organs, and actually choose them for mating. That does not exclude males with an average-sized sex organ, called a gonopodium. These fish out-compete the larger-endowed males in a predator-laden environment because they have a faster burst speed than the males with large...

Late peak may have prevented severe flu season from becoming worse

The 2004-2005 flu season was at least as severe as the 2003-2004 season, but peaked later according to data from Solucient, a leading provider of healthcare information. This later peak may have prevented the most recent flu season from being even worse. A flu season's severity is reflected in hospital admissions for community-acquired pneumonia (CAP), one of the most common complications...

Study shows humans have ability to track odors, much like bloodhounds

Though humans may never match the tracking ability of dogs, we apparently have the ability to sniff out and locate odors, according to a new study by scientists from the University of California, Berkeley. Student volunteers presented with odors to one nostril or the other could reliably discern where the odor was coming from, and functional magnetic resonance images of their brains showed...

Evolution of taste receptor may have shaped human sensitivity to toxic compounds

Researchers have found new evidence suggesting that the ability to taste bitter compounds has been strongly advantageous in human evolution. Animals rely on chemical perception, including the senses of taste and smell, for protection against the harmful compounds found in nature. It is widely believed that behavioral and dietary choices may have reduced the importance of such chemical perc...

Purdue scientists may have found key to halting spinal cord damage

Purdue University researchers may have isolated the substance most responsible for the tissue damage that follows initial spinal cord injury, a discovery that could also improve treatments for a host of other neurodegenerative conditions. A research team led by Riyi Shi (REE-yee SHEE) has found that a chemical called acrolein, a known carcinogen, is present at high levels in spinal tissue...

Could better mangrove habitats have spared lives in the 2004 tsunami?

Accounts of the tsunami that killed over a quarter of a million people in Southeast Asia on the 26th of December, 2004, slowly disappear from the media, but the event is nevertheless heavily burned into the memories of those who are directly involved. In the aftermath of the disaster, academics and politicians alike are trying to investigate how the number of casualties could have been reduced an...

Human embryonic stem cells have the potential to develop into eggs and sperm in the laboratory

Scientists in the UK have proved that human embryonic stem cells can develop in the laboratory into the early forms of cells that eventually become eggs or sperm. Their work opens up the possibility that eggs and sperm could be grown from stem cells and used for assisted reproduction, therapeutic cloning and the creation of more stem cells for further research and for the improved treatments for...

Plants have a double line of defence

Max Planck researchers in Cologne, Germany demonstrate that a multi-step defence system underlies the durable resistance of plants to fungal parasitesPlants are exposed to many different pathogens in the environment. Only a few of these pathogens, however, are able to attack a species of plant and "make it sick". If a particular pathogen is unable to attack a plant, that means that the plant is r...

Tetanus toxin found to have therapeutic properties

A team of researchers from the Department of Biochemistry and Molecular Biology and the Institute of Neuroscience at the Universitat Autònoma de Barcelona has discovered that tetanus toxin, which causes tetanus, could be extremely useful as a therapy against psychological disorders such as depression, anxiety and anorexia, and to slow the progress of neurodegenerative disorders such as Parkinson'...

Treatments have same target, different responses for lung cancer patients with genetic mutation

The gene mutation that identifies the lung cancer patients most likely to respond to the drug gefitinib (Iressa) is not associated with a response to the drug cetuximab (Erbitux), according to a new study published in the August 17 issue of the Some patients with non�small-ce...

Identical twins may have more differences than meet the eye

Identical twins lose some fundamental similarities as they grow older, a new study reports. Researchers report in this week's Proceedings of the National Academy of Sciences that these differences may stem from changes in the epigeno...

Elusive salamanders have role in developing new sampling models

Rare salamanders at a Georgia military base are the guinea pigs for Oak Ridge National Laboratory researchers whose goal is to develop methods to better determine whether a species has vanished. After not finding any flatwoods salamanders since 2001, Fort Stewart biologists were a bit concerned and were looking for a better survey method, said Mark Bevelhimer, an aquatic ecologist and mem...

DDT-resistant insects have additional genetic advantage that helps resistance spread

Insects that can withstand the powerful pesticide DDT that was banned in the 1970s have an additional genetic advantage over their rivals that has helped them spread across the globe ever since, according to research published in Current Biology tomorrow (9 August 2005). This discovery overturns current theories that resistance to pesticides burdens insects with a genetic disadvantage tha...

MicroRNAs have shaped the evolution of the majority of mammalian genes

RNA continues to shed its reputation as DNA's faithful sidekick. Now, researchers in the lab of Whitehead Institute Member David Bartel have found that a class of small RNAs called microRNAs influence the evolution of genes far more widely than previous research had indicated. "MicroRNAs are affecting the majority of protein-coding genes, either at a functional level or an evolutionary lev...

Plants, too, have ways to manage freeloaders

Many, if not all, plants maintain relationships with bacteria, and like any hardworking homeowner, they have developed ways to get rid of freeloaders, University of California, Berkeley, biologists have found. In a study of a coastal California lupine that harbors nitrogen-fixing bacteria in its roots, UC Berkeley researchers have shown that the roots respond differently to bacteria that e...

Have a taste for fat? Yes! A sensor in the mouth promotes preference for fatty foods

The sense of taste informs the organism about the quality of ingested food. It comprises five sub-modalities that perceive sweet, salt, sour, bitter, and umami stimuli. The possibility for an additional taste modality directed to lipid has often been suggested because many animals exhibit a spontaneous attraction for fats, but the existence of an actual sensor remained a matter of debate. <...

MicroRNA may have fail-safe role in limb development

A tiny strand of molecules plays a role in how our arms and legs develop and grow - a finding that sheds light on perplexing bits of material once dismissed as genetic "junk," say scientists at the University of Florida and Harvard University. The research, available today in the online edition of Nature, may help scientists understand whether bits of RNA called microRNAs act as protective...

Genetic study shows humans have pushed orangutans to the brink of extinction

A new study published in the open-access journal PLoS Biology shows strong genetic evidence of a catastrophic collapse in orangutan populations living in the fragmented forests of the Kinabatangan Wildlife Sanctuary in Sabah, Malaysia. Benoit Goossens, Lounès Chikhi, Michael Bruford, and their colleagues report that the collapse occurred within the past hundred years, and most likely wit...

Medical experts: US unlikely to have enough vaccines to stop avian flu

A group of medical experts who attended a national avian flu conference last fall believe there is little chance the United States will be able to manufacture and stockpile enough vaccine or antiviral medication to stop a bird flu pandemic should the virus mutate into a form that can be spread easily from human to human, according to a survey led by researchers at Carnegie Mellon University. The...

Deep-rooted plants have much greater impact on climate than experts thought

Trees, particularly those with deep roots, contribute to the Earth's climate much more than scientists thought, according to a new study by biologists and climatologists from the University of California, Berkeley. While scientists studying global climate change recognize the importance of vegetation in removing carbon dioxide from the atmosphere and in local cooling through transpiration,...

Parts of the Caribbean and Central America are likely to have less summer rain

Parts of the Caribbean and Central America are likely to experience a significant summer drying trend by the middle of this century, UCLA atmospheric scientists will report in the April 18 issue of Proceedings of the National Academy of Sciences (PNAS). Their research is based on an analysis of 10 global climate computer simulations, from the U.S. National Center for Atmospheric Research,...

Study shows that cells have a natural defense against HIV

Scientists here have discovered a previously unknown mechanism that cells use to fight off the human immunodeficiency virus (HIV), the cause of AIDS. The study was led by...

Do plants have the potential to vaccinate against HIV?

Scientists have developed a new kind of molecule which they believe could ultimately lead to the development of a vaccine against HIV using genetically modified tobacco. Writing in Plant Biotechnology Journal, Dr Patricia Obregon and colleagues from St George's, University of London along with researchers at the University of Warwick say they have overcome a major barrier that has so far frustrat...

Males with elevated levels of testosterone lead shorter lives but have more success siring offspring

Comparative studies have studied testosterone levels and related them to mating systems and aggression, but very few studies have attempted to relate testosterone to fitness, that is, the combination of lifetime reproductive success and survival, in the wild or experimentally. Over nine breeding seasons, Wendy Reed (North Dakota State University) and her colleagues followed a group of dark-eyed j...

Statins have neutral effect on risk of cancer

The cholesterol-lowering medications called statins do not appear to reduce the incidence of cancer or cancer deaths, according to a meta-analysis of previous studies in the January 4 issue of JAMA. Other studies have suggested that statins reduce the risk of developing cancer, the authors provide as background information in the review article. "Statins have been studied in numerous larg...

Stable polymer nanotubes may have a biotech future

Scientists at the National Institute of Standards and Technology (NIST) have created polymer nanotubes that are unusually long (about 1 centimeter) as well as stable enough to maintain their shape indefinitely. Described in a new p...

One-third of adults with diabetes still don't know they have it

The prevalence of diagnosed diabetes in U.S. adults age 20 and older has risen from about 5.1 percent to 6.5 percent, according to researchers at the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC), who analyzed national survey data from two periods--1988 to 1994 and 1999 to 2002. However, the percentage of adults with undiagnosed diabetes did not cha...

Patients and their doctors have different perceptions about HIV and its treatment

According to results of a nation-wide study published in the latest issue of SAGE Publications' Journal of the International Association of Physicians in AIDS Care (JIAPAC), HIV positive patients and their doctors have very different views about the disease and how it's treated. The study uncovered differences of opinion between patients and physicians about the initiation of treatment, th...

Breast stem cells have features similar to 'basal' tumors

The most aggressive form of breast cancer may originate from breast stem cells that have undergone genetic mishaps. Victorian Breast Cancer Research Consortium scientists from The Walter and Eliza Hall Institute, using mouse models, have discovered that breast stem cells do not express receptors for the female hormones oestrogen or progesterone. These and otherfeatures of the stem cell re...

Global warming may have damaged coral reefs forever

Global warming has had a more devastating effect on some of the world's finest coral reefs than previously assumed, suggests the first report to show the long-term impact of sea temperature rise on reef coral and fish communities. Large sections of coral reefs and much of the marine life they support may be wiped out for good, say the international team of researchers, who surveyed 21 sit...

Bacteria have their own immune system protecting against outside DNA

Bacteria like Salmonella have a complicated immune system that helps them recognize and isolate foreign DNA trying to invade their cell membrane, according to a University of Washington-led study in the June 8 issue of Science Express. The research, which also included scientists at the Sidney Kimmel Cancer Center in San Diego, could have major implications for understanding the evolution of dise...

Where have all the butterflies gone?

Cold, wet conditions early in the year mean that 2006 is shaping up as the worst year for California's butterflies in almost four decades, according to Art Shapiro, professor of evolution and ecology at UC Davis. That's a turnaround from last spring, when millions of painted lady butterflies migrated through the Central Valley. But other species have seen steep declines in recent years and...

Man may have caused pre-historic extinctions

New research shows that pre-historic horses in Alaska may have been hunted into extinction by man, rather than by climate change as previously thought. The discovery by Andrew Solow of Woods Hole Oceanographic Institute, US, David Roberts of the Royal Botanic Garden, Kew and Karen Robbirt of the University of East Anglia (UEA) is published this week in Proceedings of the National Academy o...

Protowings may have helped bird ancestors cover rough terrain

Biologists have long argued about how birds evolved the ability to fly, because it is not immediately evident what improvement in fitness would result from ancestral, partly evolved wings. Two theories have recently dominated the debate: one postulates that flight evolved in tree-dwelling ancestors that used their forelimbs to help them glide, while the other considers ancestral birds to be terre...

Humpback whales have brain cells also found in humans

Cetaceans, the group of marine mammals that includes whales and dolphins, have demonstrated remarkable auditory and communicative abilities, as well as complex social behaviors. A new study published online November 27, 2006 in The Anatomical Record, the official journal of the American Association of Anatomists,compared a humpback whale brain with brains from several other cetacean species and f...

Oldest animal fossils may have been bacteria

The oldest-known animal eggs and embryos, whose first pictures made the cover of Nature in 1998, were so small they looked like bugs ?which, it now appears, they may have been. The discovery "complicates our understand...