Friday, May 30, 2008

Nanophotonics changes protein colours

Scientists of the University of Twente and the AMOLF Institute succeeded in changing the colour of light that is emitted by fluorescent protein molecules, without modifying the molecular structure. By placing the proteins in a photonic crystal, the colour of the light alters. This results in a powerful new tool for investigating the influence of light on biological systems. The coloured proteins are on the cover of April’s Small magazine.

Protein molecules emitting visible light, so called fluorescent proteins, are crucial in scientific research on processes within a living cell. Tuning the colour of light can, up to now, only be done by altering the molecular structure. By using a so-called photonic crystal, the UT scientists have found an attractive alternative. These are highly ordered air spheres with dimensions within the range of the wavelength of light. Because of this ordering, strong interference effects will show: this causes a ‘forbidden range’ of wavelengths, of which no light transmission will be possible inside the crystal. Any light source placed within the crystal will have to transmit its light in another colour or direction.

For the first time, a natural lightsource like a protein is now placed in a crystal. The structure of the crystal has systematically been varied to observe colour changes. Around the ‘forbidden zone’ or stop band, some colours will be enhanced and others suppressed. Thus, using photonic crystals, a whole new range of possibilities opens up for studying biological process, within a new discipline called biophotonic engineering.

The upper two pictures show which colours are reflected by the two crystals: inside the crystals there’s no propagation of light of these specific colours. The second row of pictures show the yellow-orange emission of the protein, shifting towards red and bright green. The spectra show the stop bands as a yellow zone. The ‘up’ arrow shows the amplification of light in the specified wavelength area.

The research has been done within the groups Biophysical Engineering of Prof. Vinod Subramaniam and Complex Photonic Systems of Prof. Willem Vos, both of them part of the MESA+ Institute for Nanotechnology of the University of Twente. This was a joint project with the Institute for Atomic and Molecular Physics (AMOLF) in Amsterdam.

SOURCE : University of Twente

Thursday, May 29, 2008

Jurassic Crocodile Is Unearthed From Blue Mountains In Eastern Oregon

An ancient sea-going crocodile has surfaced from the rocks of Crook County in eastern Oregon. Really.

It's discovery by the North American Research Group (NARG), whose members were digging for Jurassic-age mollusks known as ammonites, is another confirmation that the Blue Mountains consist of rocks that traveled from somewhere in the Far East, says retired University of Oregon geologist William Orr, who was called in to examine the find for the state.

The remains - about 50 percent of a 6- to 8-foot reptile, including long, needlepoint teeth - were found imbedded in Jurassic rock on private property in the Snowshoe Formation of the Izee Terrane south of Dayville, Ore. Rocks containing the fossils were slowly cut out of the rock, after NARG members realized that the linear appearance of the fossils in the region's hard r

ocks suggested that a whole creature had been found, Orr said.

"This taxon was a crocodile-like creature but had a fish tail," said Orr, a NARG adviser and director of the Thomas Condon State Museum of Fossils at the University of Oregon. "This creature lived in Jurassic times, so it's 150 to 180 million years old. It probably lived in an area from Japan to East Timor, somewhere in the western Pacific in a tropical estuarine environment."

The remains of the crocodile, believed to be from the species Thalattosuchia

and member of the Metriorhynchids group, now belong to the state, Orr said. The remains will be displayed on loan to the Rice Northwest Museum of Rocks and Minerals in Hillsboro, Ore., after undergoing an expected two-year analysis at the University of Iowa. The Hillsboro museum is operated by NARG, whose members are private researchers with experience and interests in paleontology, paleonbotany and geology who study the Pacific Northwest.

Andrew Bland, one of nine NARG members seeking fossils, first located the crocodile bones during a weekend trip in October 2005. "I followed the bone fragments I was finding up hill a few feet to the area they were weathering out of," Bland wrote in a group newsletter. "I started to dig and found more bone material. It was hard for me to stop digging, as I wanted to uncover more."

Thalattosuchia, a predator believed to have been common around much of the world during the Jurassic Period (142 million to 208 million years ago) was named in 1901 by German researcher Eberhard Fraas. Based on locations where fossils have been found, scientists have theorized that Thalattosuchians may have moved from semi-aquatic freshwater reptiles into fully ocean forms.

Fossils similar to the Oregon crocodile appear today in many areas around South China, Orr said.

Orr theorizes that the remains in Oregon migrated eastward in rock by continental drift, a theory of land movement in geological time now encompassed under plate tectonics. Terrane formations, such as those where these fossils were found, are believed to be portions of the earth's crust riding apart of a plate that is pushed upward at contact with another plate.

The reptiles' short stubby legs would have allowed them to move about land, where they may have laid eggs. But also, the creatures may have had webbed feet, which, in combination with the fish-like tail, would have made them rapid swimmers, allowing them to hunt along the surface of aquatic environments, scientists have theorized.

Fossils from other crocodile families and other reptiles, especially ichthyosoaurs, from the Mesozoic Era (65 million to 248 million years ago) have been found previously in Oregon, but none have been as old as the newly found crocodile, Orr said.

"While fossil marine crocodiles frequently occur in Jurassic rocks of Europe and Africa, they are scarce in North America," Orr and his wife Elizabeth L. Orr, a courtesy research assistant in the department of geological sciences, noted in their book "Oregon Fossils." And while these reptiles lived during the age of dinosaurs, only a single fragmentary dinosaur bone, from the Cretaceous Period (65 million to 144 million years ago), has been discovered in the state.

The new discovery, Orr said, suggests that dinosaur fossils "must be out there somewhere, but we just haven't looked hard enough."

SOURCE : University of Oregon, Science Daily

The monster is even bigger than earlier estimates

Natural History Museum in Oslo, Norway has announced the discovery of one of the largest dinosaur-era marine reptiles ever found – an enormous sea predator known as a pliosaur estimated to be almost 15 meters (50 feet) feet long.

The 150 million year-old Jurassic fossil was discovered on the remote Norwegian archipelago of Svalbard, at 78 degrees north latitude, approximately 1300 km (800 miles) from the North Pole. It was found in the summer of 2006 by a team of Norwegian paleontologists and volunteers from the University of Oslo Natural History Museum, led by Dr. Jørn Hurum. The fossil was excavated in the summer of 2007 and has until now been prepared and conserved by a team at the Natural History Museum in Oslo .

A pliosaur is a type of plesiosaur, a group of extinct reptiles that lived in the world's oceans during the age of dinosaurs. Pliosaurs had a tear-drop shaped body and two sets of powerful paddles that it used to “fly” through the water. Their short neck supported a massive skull full of an impressive set of teeth. Pliosaurs were the top predators in the sea at the time, preying upon squid-like animals, fish, and even other marine reptiles.
Pliosaurs were large reptiles that averaged 5-6 meters (16-20 feet) in length. One of the largest pliosaurs known is the Australian giant Kronosaurus , which measures in at 10-11 meters (33-36 feet) long. The new Norwegian find, named “The Monster” by team members, is estimated to be about 15 meters (50 feet) long, making it one of the longest and most massive plesiosaurs yet found.

“Not only is this specimen significant in that it is one of the largest and relatively complete plesiosaurs ever found, it also demonstrates that these gigantic animals inhabited the northern seas of our planet during the age of dinosaurs” said Dr. Patrick Druckenmiller, a plesiosaur specialist at the University of Alaska Museum, and a member of the expedition that found and excavated the fossil.

The team made the discovery in the summer of 2006, when parts of the skeleton, including skull fragments, were found weathering out of the side of a mountain.

“We knew immediately that this was something special. The large pieces of bone and the structure on the fragments told us immediately that this was something big” said Dr. Jørn Hurum.

A larger crew returned in August of 2007 to excavate the fossil. After removing about hundred tons of rock by hand the team was rewarded by uncovering a significant portion of the skeleton.

“Although we didn't get the entire skeleton, we found many of the most important parts, including portions of the skull, teeth, much of the neck and back, the shoulder girdle, and a nearly complete forelimb (paddle)” said Druckenmiller, “Amazingly, the paddle alone is nearly 10 feet long.”

During its excavation in the summer of 2007, the team of paleontologists and volunteers had to endure challenging arctic weather – high winds, rain and fog, and temperatures hovering around freezing. The team completed their fieldwork in a mid-August blizzard. Throughout the three-week field season the team also had to be constantly on the alert for polar bears.

Although the crew focused on removing the “The Monster”, parts of two other marine reptiles were also collected – a long-necked plesiosaur and an ichthyosaur, a type of extinct sea reptile form the age of dinosaurs that superficially resembled modern dolphins. Based on the wealth of finds, scientists now recognize Svalbard as home to one of the richest accumulations of marine reptiles in the world.

“The scientific value of such a large locality with unknown species of marine reptiles is just staggering” Jørn Hurum comments.

The bones collected last summer are currently undergoing the slow process of cleaning at the Natural History Museum in Oslo . (til lab side)

“From the bones we have finished stabilizing so far this absolutely looks like a new species” Jørn Hurum tells enthusiastically.

Last summer's field work ended on a high note; after the team finished excavating the new find, parts of a skull and skeleton from another gigantic pliosaur, possibly of the same new species, were found weathering out at a different site. The team is currently planning to return this upcoming summer in order to excavate the skull during Svalbard 's short summer field season. (want to be a sponsor? - please contact

“All together we have GPS-coordinates on 40 skeletons of different marine reptiles in the area. We will have work for many years to come” Jørn Hurum comments with a smile.

The scientific description of the monster and other new marine reptiles from the locality will be parts of a Ph.D. study by one of the members of the crew, Espen M. Knutsen.

SOURCE : University of Oslo

Wednesday, May 28, 2008

Origin Of Cells For Connective Tissues Of Skull And Face Challenged

With improved resolution, tissue-specific molecular markers and precise timing, University of Oregon biologist James A. Weston and colleagues have possibly overturned a long-standing assumption about the origin of embryonic cells that give rise to connective and skeletal tissues that form the base of the skull and facial structures in back-boned creatures from fish to humans.

Weston and co-authors from the Max Planck Institute of Immunology in Germany and the French National Scientific Research Centre at the Curie Institute document their potentially textbook-changing case in an article appearing online the week of May 19-23 ahead of regular publication in the Proceedings of the National Academy of Sciences.

The cells in question, they argue, do not come from a portion of embryonic neural epithelium called the neural crest, as widely believed, but rather from a distinct thin layer of epidermal epithelial cells next to it. "Our results," Weston said, "could lead to a better understanding of the etiology of craniofacial defects, as well as the evolution of the head that distinguishes vertebrates from other creatures."

The neural crest was first identified by classical embryologists in the late 19th and early 20th centuries and has been one of the most studied embryonic tissues. Conventional wisdom says that the neural crest gives rise to skeletal and connective tissue of the head and face, as well as a wide diversity of other stem cells that migrate to many places in the vertebrate embryo, where they spawn the cells that create the peripheral nervous system, and pigment cells in skin and hair (or scales and feathers).

The new study is part of research done over 25 years in Weston's quest to understand early development of the neural crest and explore alternative explanations for sometimes differing findings involving its assumed cell lineages. Weston noted that mutations in mice that adversely affected development of the peripheral nervous system or pigmentation did not affect craniofacial structures, whereas mutations that caused abnormal development of skeletal and connective tissue of the head and face did not alter neural crest-derived pigment or peripheral nervous system cells.

This paradox, he said, led him to wonder if different genetic programs were required to function in distinct embryonic precursors of these tissues. "In our new paper," he said, "we finally were able to re-examine some of the underlying assumptions that have led to the conventional wisdom about the source of the embryonic cell lineages that give rise to the skeleton and connective tissue of the head and face."

In the mouse embryo at eight days gestation, Weston and collaborators used high-resolution imaging and immunostaining techniques to identify and track the dispersal of cells known to jump start connective and skeletal tissue development. They were able to see clearly that these cells came from the non-neural layer of cells rather than from the neural crest. The same distinction also exists in chicken embryos during the first few days of gestation, Weston noted. "Looking at the right time is very important," he said.

Weston argues that this non-neural epithelium is indeed distinct from the neural crest, because its cells contain characteristically different molecules. He and colleagues dispute suggestions that this non-neural structure is simply a sub-domain of the neural crest. "These cells emerge at a different time in development and disperse in the embryo before neural crest cells begin to migrate," Weston said.

"New technologies let us see cell types more clearly than ever before," said Weston, a member of the UO's Institute of Neuroscience. "We previously had discovered that a molecule that marks cell surfaces in the non-neural epithelium reveals a very sharp boundary between this non-neural epithelium and the neural tissue connected to the neural crest. In this study, we took a closer look."

They located a population of cells in the non-neural epithelium that express other molecules that "do not appear to originate from the neural crest," said Weston, who retired in 2001 but continued to teach in the College of Arts and Sciences until 2006. He still collaborates in some research with colleagues at the UO and at various labs around the world.

"I think our results have two important messages," he said. "First, it is important to identify and validate -- rather than ignore -- assumptions; and second, because we identified an alternative embryonic cell lineage as the source of the head and facial structures, we can now more effectively analyze and understand the molecular-genetic mechanisms that regulate the normal and abnormal development of these structures."

Co-authors with Weston were Marie Anne Breau, Thomas Pietri, and Jean Paul Thiery, all of the Curie Institute, and Marc P. Stemmler of the Max Planck Institute of Immunobiology. Pietri was a graduate student in the Curie Institute, where the project began in 2002, while Weston was on a fellowship, and now is a postdoctoral researcher with Phil Washbourne in the UO Institute of Neuroscience. Thiery, now based at the Institute of Molecular and Cell Biology of the Agency for Science, Technology and Research in Singapore, is a corresponding author with Weston on the PNAS paper.

SOURCE : University of Oregon, Science Daily

Giant Flying Reptiles Preferred To Walk

New research into gigantic flying reptiles has found that they weren't all gull-like predators grabbing fish from the water but that some were strongly adapted for life on the ground.

Pterosaurs lived during the age of dinosaurs 230 to 65 million years ago. A new study by researchers at the University of Portsmouth on one particular type of pterosaur, the azhdarchids, claims they were more likely to stalk animals on foot than to fly.

Until now virtually all pterosaurs have been imagined by palaeontologists to have lived like modern seabirds: as gull- or pelican-like predators that flew over lakes and oceans, grabbing fish from the water. But a study of azhdarchid anatomy, footprints and the distribution of their fossils by Mark Witton and Dr Darren Naish shows that this stereotype does not apply to all flying reptiles and some were strongly adapted for terrestrial life.

Azhdarchids were probably better than any other ptersosaurs at walking because they had long limbs and skulls well suited for picking up small animals and other food from the ground.

Azhdarchids, named after the Uzbek word for 'dragon', were gigantic toothless pterosaurs. Azhdarchids include the largest of all pterosaurs: some had wingspans exceeding 10 metres and the biggest ones were as tall as a giraffe.

Dr Naish said: "Azhdarchids first became reasonably well known in the 1970s but how they lived has been the subject of much debate. Originally described as vulture-like scavengers, they were later suggested to be mud-probers (sticking their long bills into the ground in search of prey), and later still suggested to make a living by flying over the water's surface, grabbing fish.

"Other lifestyles have been suggested too. These lifestyles all seem radically divergent so Mark and I sat down and carefully examined the evidence and we argue that azhdarchids were specialised terrestrial stalkers. All the details of their anatomy, and the environment their fossils are found in, show that they made their living by walking around, reaching down to grab and pick up animals and other prey."

Animals like azhdarchids no longer exist but the closest analogues in the modern world are large ground-feeding birds like ground-hornbills and storks.

The researchers studied fossils in London, Portsmouth and Germany and compared the anatomy of azhdarchid with those of modern animals. This showed that azhdarchids were strikingly different from mud-probers and animals that grab prey from the water's surface while in flight.

Dr Naish said: "We also worked out the range of motion possible in the azhdarchid neck: this bizarrely stiff neck has previously been a problem for other ideas about azhdarchid lifestyle, but it fits with our model as all a terrestrial stalker needs to do its raise and lower its bill tip to the ground."

Other aspects of azhdarchid anatomy, such as their relatively small padded feet and long but weak jaws often pose problems in other proposed lifestyles but fit perfectly with the terrestrial stalker hypothesis. Mr Witton said: "The small feet of azhdarchids were no good for wading around lake margins or swimming should they land on water but are excellent for strutting around on land. As for what azhdarchids would eat, they'd have snapped up bite-size animals or even bits of fruit. But if your skull is over two metres in length then bite-size includes everything up to a dinosaur the size of a fox."

The researchers found that over 50 percent of azhdarchid fossils come from sediments that were laid down inland. Significantly, the only articulated azhdarchid fossils we have come from these inland sediments.

SOURCE : Public Library of Science, Science Daily

Bone repair using patient's own stem cells

Enzyme induces adult stem cells to grow bone

Hitherto it has been difficult to induce adult human stem cells to produce bone, e.g. in order to repair bone tissue. Researchers at the University of Twente have shown that if the enzyme PKA is previously activated in the stem cells in the lab, following implantation this results in substantial bone formation. This opens up new ways of repairing bone tissue using cell material from the patient. The researchers are publishing their work in the Proceedings of the National Academy of Sciences (PNAS).

In animals, ‘adult’ mesenchymal stem cells have already been used successfully to grow fresh bone. Bone formation using human adult stem cells, e.g. from bone marrow, has been less successful, which has hitherto limited the alternatives hospitals can offer for repairing damaged tissue other than spontaneous healing. Activating the PKA enzyme prior to implantation, however, produces a dramatic improvement in ‘in vivo’ bone growth. The cells can be observed maturing into bone cells already in the lab; once sown on a carrier and implanted in a mouse, the bone grows well.

Encouraging the neighbours

The enzyme protein kinase A (PKA) is responsible for many processes in a cell. The messenger ‘cyclic AMP’ activates PKA: adding it to the stem cells ensures that they stimulate one another, the researchers think. Not only does cyclic AMP promote maturation into bone cells; the cells themselves also secrete various substances that stimulate bone growth. This may explain why mesenchymal stem cells treated with cyclic AMP form significantly more bone than those without the stimulus.

The advantage of administering a bone-growth-stimulating substance in advance is that it can be removed just before implantation. Experiments to date have mainly used high concentrations of a bone-growth-stimulating hormone, e.g. incorporated in the carrier on which the cells are ‘sown’. In the new approach not only are the hormone concentrations lower, they also more closely resemble the cocktail of hormones normally involved in bone growth.

This is the second time in a short space of time that the researchers, led by Dr Jan de Boer, have published in PNAS: earlier this month they published an article on a major breakthrough in the use of embryonic stem cells to grow bone. Both methods are promising when it comes to repairing bone tissue in future using cells from the patient’s own body. Compact bioreactors will be developed to grow cells quickly into tissue that can be used in the operating theatre.

The research was carried out at the Tissue Regeneration Department of the University of Twente’s Institute for Biomechanical Technology (BMTI). The researchers collaborated with fellow scientists at UMC Utrecht and the Erasmus Medical Center in Rotterdam.

SOURCE : University of Twente

Sunday, May 25, 2008

Hissing Cockroaches Are Popular, But They Also Host Potent Mold Allergens

Ohio State University, Their gentle nature, large size, odd sounds and low-maintenance care have made Madagascar hissing cockroaches popular educational tools and pets for years. But the giant insects also have one unfortunate characteristic: Their hard bodies and feces are home to many mold species that could be triggering allergies in the kids and adults who handle the bugs, according to a new study.

Researchers have identified 14 different types of mold on and around this species of cockroach, including several molds associated with allergies and others that can cause secondary infections if they enter the lungs or an open wound.

“This is mainly a point of public awareness,” said Joshua Benoit, lead author of the study and a doctoral candidate in entomology at Ohio State University. “We are not criticizing their use. We are just saying that if you handle these cockroaches, you should wash your hands when you’re done.

“It’s also best to maintain the cage. It’s not a pet you can ignore,” he said. “Without regular cleaning, feces will build up, and the old exoskeletons they shed will build up. And that’s where a lot of the problems happen.”

The natural life of the Madagascar hissing cockroach, or Gromphadorhina portentosa, is not well understood. But in captivity, the insects thrive on dog food and fruit, reproduce plentifully and do not bite. They grow to between 2 and 3 inches long and 1 inch wide, and will make their characteristic hissing sound if they are squeezed or otherwise feel threatened.

Benoit, an allergy sufferer himself, suspected the insects’ large bodies and moist living environments might combine to create a prime breeding ground for mold.

Some people are allergic to the species of cockroaches that are household pests. In those cases, the bugs’ actual bodies contain allergens. In the case of the Madagascar hissing cockroaches, the most potent mold allergens live on and around the insects instead.

Benoit and colleagues examined the insects from an Ohio State-based colony as well as those found in home collections, zoos, pet stores and science classrooms across Ohio.

The research group tested the feces first, and, as expected, found mold in the bugs’ waste. Then the team examined the giant cockroaches themselves, both outside and inside their bodies, to see what other allergens might be present.

The most commonly found mold species found on the body surfaces of young and adult Madagascar hissing cockroaches were Rhizopus, Penicillium, Mucor, Trichoderma and Alternaria, several of which are listed by the Centers for Disease Control and Prevention (CDC) as common indoor molds. Colonies of the mold species Aspergillus niger, a common contaminant of food, were particularly plentiful in the feces and external shells that had been discarded as the insects molted.

Few molds were found inside the cockroaches’ bodies.

Molds are fungi that grow best in humid conditions, and spread and reproduce by making spores. Benoit said all of the mold species found on and around the hissing cockroaches are capable of producing huge quantities of spores. And the spores themselves can get on bug handlers’ skin or be inhaled, triggering allergic responses in those sensitive to the molds.

For people who are allergic to molds, exposure can cause symptoms such as nasal stuffiness, itchy or burning eyes, wheezing or skin irritation, according to the CDC. Some people with serious allergies to molds may have more severe reactions.

Benoit now is pursuing additional studies on one surprise among the findings: Symbiotic mites also live on the cockroaches, and help keep them clean.

“The mites sweep the surface and remove old food particles and debris, so they remove places on which fungi can grow,” Benoit said.

The research is published in the March issue of the journal Mycoses. Benoit conducted the project with Jay Yoder and Brian Glenn of Wittenberg University and Lawrence Zettler of Illinois College.

SOURCE : Ohio State University, ScienceDaily

Molecular Analysis Confirms Tyrannosaurus Rex's Evolutionary Link To Birds

Harvard University, Putting more meat on the theory that dinosaurs' closest living relatives are modern-day birds, molecular analysis of a shred of 68-million-year-old Tyrannosaurus rex protein -- along with that of 21 modern species -- confirms that dinosaurs share common ancestry with chickens, ostriches, and to a lesser extent, alligators.The work, published in the journal Science, represents the first use of molecular data to place a non-avian dinosaur in a phylogenetic tree that traces the evolution of species. The scientists also report that similar analysis of 160,000- to 600,000-year-old collagen protein sequences derived from mastodon bone establishes a close phylogenetic relationship between that extinct species and modern elephants."These results match predictions made from skeletal anatomy, providing the first molecular evidence for the evolutionary relationships of a non-avian dinosaur," says co-author Chris Organ, a postdoctoral researcher in organismic and evolutionary biology at Harvard University. "Even though we only had six peptides -- just 89 amino acids -- from T. rex, we were able to establish these relationships with a relatively high degree of support. With more data, we'd likely see the T. rex branch on the phylogenetic tree between alligators and chickens and ostriches, though we can't resolve this position with currently available data."The current paper builds on work reported in Science last year. In that paper, a team headed by John M. Asara and Lewis C. Cantley, both of Beth Israel Deaconess Medi-cal Center (BIDMC) and Harvard Medical School (HMS), first captured and sequenced tiny pieces of collagen protein from T. rex. For the current work, Organ and Asara and their colleagues used sophisticated algorithms to compare collagen protein from several dozen species. The goal: placing T. rex on the animal kingdom's family tree using molecu-lar evidence."Most of the collagen sequence was obtained from protein and genome databases but we also needed to sequence some critical organisms, including modern alligator and modern ostrich, by mass spectrometry," says Asara, director of the mass spectrometry core facility at BIDMC and instructor in pathology at HMS. "We determined that T. rex, in fact, grouped with birds -- ostrich and chicken -- better than any other organism that we studied. We also show that it groups better with birds than modern reptiles, such as alliga-tors and green anole lizards."While scientists have long suspected that birds, and not more basal reptiles, are di-nosaurs' closest living relatives, for years that hypothesis rested largely on morphological similarities in bird and dinosaur skeletons.The scraps of dinosaur protein were wrested from a fossil femur discovered in 2003 by John Horner of the Museum of the Rockies in a barren fossil-rich stretch of land that spans Wyoming and Montana. Mary H. Schweitzer of North Carolina State Univer-sity (NCSU) and the North Carolina Museum of Natural Sciences discovered soft-tissue preservation in the T. rex bone in 2005; Asara became involved in analysis of the colla-gen protein because of his expertise in mass spectrometry techniques capable of se-quencing minute amounts of protein from human tumors. While it appears impossible to salvage DNA from the bone, Asara was able to extract precious slivers of protein.The current work by Organ and Asara suggests that the extracted protein from the fossilized dinosaur tissue is authentic, rather than contamination from a living spe-cies."These results support the endogenous origin of the preserved collagen mole-cules," the researchers write.Organ, Asara, Schweitzer, and Cantley's co-authors on the Science paper are Wenxia Zheng of NCSU and Lisa M. Freimark of BIDMC. Their research was funded by the National Institutes of Health, the National Science Foundation, the Paul F. Glenn Foundation, and the David and Lucile Packard Foundation.

Saturday, May 24, 2008

Daily Glass Of Wine Could Improve Liver Health

University of California - San Diego Health Sciences
, Researchers at UC San Diego School of Medicine are challenging conventional thinking with a study showing that modest wine consumption, defined as one glass a day, may not only be safe for the liver, but may actually decrease the prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD).

The study, which appears in the June 2008 issue of the journal Hepatology, showed that for individuals who reported drinking up to one glass of wine per day, as compared to no alcohol consumption, the risk of liver disease due to NAFLD was cut in half. In contrast, compared with wine drinkers, individuals who reported modest consumption of beer or liquor had over four (4) times the odds of having suspected NAFLD.

NAFLD is the most common liver disease in the United States, affecting over 40 million adults. Previous research has shown that as many as five percent of adults with NAFLD will develop cirrhosis. The major risk factors for NAFLD are similar to many of the risk factors for cardiovascular disease—obesity, diabetes, high triglycerides, and high blood pressure. Multiple studies have shown that modest alcohol consumption may reduce the risk for heart disease. However, recommendations for modest alcohol consumption in individuals at risk for cardiovascular disease have overlooked that these same people are also at an increased risk for NAFLD. Thus, there exists a dilemma as to whether modest alcohol consumption for the heart is safe in regards to the liver. The UC San Diego investigators sought to clarify this important question.

“The results of this study present a paradigm shift, suggesting that modest wine consumption may not only be safe for the liver but may actually decrease the prevalence of NAFLD. The odds of having suspected NAFLD based upon abnormal liver blood tests was reduced by 50 percent in individuals who drank one glass of wine a day,” said Jeffrey Schwimmer, M.D., associate professor of gastroenterology, hepatology and nutrition, Department of Pediatrics, UC San Diego School of Medicine and Director, Fatty Liver Clinic at Rady Children’s Hospital San Diego. The result remained constant, even after adjusting for age, sex, race, education, income, diet, physical activity, body mass index, and other markers of health status.

Research did not provide any support for drinking larger amounts. “We want to emphasize that people at risk for alcohol abuse should not consider consuming wine or any other alcoholic beverage,” said Schwimmer, who also pointed out that, although this is the first study to address this important dilemma, the findings do not address those who already have liver disease and should not be drinking alcohol at all.

“Because this effect was only seen with wine, not in beer or liquor, further studies will be needed to determine whether the benefits seen were due to the alcohol or non-alcohol components of wine,” added Schwimmer.

The cross-sectional, population-based study of nearly 12,000 participants in the National Health and Nutrition Examination Survey (NHANES) included 7,211 nondrinkers and 4,543 modest alcohol drinkers. Modest alcohol consumption was defined as up to an average of one drink per day of either four ounces of wine, 12 ounces of beer, or one ounce of liquor. NHANES is a large epidemiological survey conducted by the Centers for Disease Control and Prevention (CDC). The alcohol history was obtained by a trained interviewer, in a private room, to ensure confidentiality.

The study was funded in part with grants from the National Institutes of Health National Research Service Award (NIH NRSA) and from the National Center for Research Resources of the National Institutes of Health for the General Clinical Research Center at UC San Diego.

The research team included Schwimmer, Winston Dunn, M.D., division of gastroenterology, Department of Medicine, UC San Diego and Ronghui Xu, Ph.D., Department of Family and Preventive Medicine and Department of Mathematics, UC San Diego.

SOURCE : University of California - San Diego Health Sciences, ScienceDaily

Possible link between baby swimming and breathing problems in children

Norwegian Institute of Public Health, Children with mothers who have allergies or asthma have an increased risk of wheezing in the chest if they take part in baby swimming before 6 months of age. This is shown in a new study using data from the Norwegian Mother and Child Study (MoBa) at the Norwegian Institute of Public Health (NIPH).

The results come from a study of 30 000 participants from MoBa. Approximately 25 percent of these children took part in baby swimming from 0-6 months of age.

Most children who take part in baby swimming show no increased incidence of lower respiratory tract infections, ear inflammation (otitis media) or tightness and wheezing in the chest. Between 6-18 months the incidence of lower respiratory tract infections and otitis media were 13 percent and 30 percent respectively, whilst the proportion of children who experienced tightness or wheezing in the chest was 40 percent.

Among children of mothers with asthma and allergy, 44 percent of those who did not go swimming had tightness or wheezing in the chest. This was compared to the 47 percent of children who swam and experienced tightness and wheezing who had mothers with asthma and allergies.

- The difference is not large but it indicates a tendency to respiratory problems, says Wenche Nystad, primary author and Department Director at the NIPH’s Division of Epidemiology.

Earlier studies indicated that there can be a link between baby swimming and airway infections in children. It has been suggested that indoor environmental factors (airway irritants) such as volatile chlorination products for indoor swimming pools can affect lung epithelium and contribute to the development of respiratory illnesses like asthma among children.

- The connection between respiratory problems and baby swimming was suggested by a paediatrician who asked whether children with increased risk of asthma, who took part in baby swimming, had a greater tendency to develop respiratory diseases. Earlier studies indicated a connection but the results were uncertain. Therefore we want to carry out a more thorough study, says Nystad.

- If mother and baby are healthy, the study shows that there is no increased risk of otitis media or respiratory problems with baby swimming before six months of age.

Reference : Nystad W, Håberg SE, London S, Nafstad P, Magnus P. Baby swimming and respiratory health. Acta Paediatric. 2008; 97: 657-62.

SOURCE : Norwegian Institute of Public Health

Whale of a Mystery: Why Those Ribs?

Jennifer Viegas - Discovery News, While dissecting a pygmy right whale at The Museum of New Zealand Te Papa, scientists there discovered that the creature possessed ribs unlike those of any other whale. Only one other animal is known to have a similar set: the anteater.

The ribs suggest pygmy right whales are stiffer in the water than previously thought, moving more like fast torpedoes than undulating fish.

"The international research team that just completed the dissection determined that the whale's ribs were flattened and overlapping," Te Papa museum spokesperson Jane Keig told Discovery News.

Sentiel Rommel, a lecturer in oceanography from the University of Maine, participated in the project.

He explained that a small amount of flesh between each of the ribs allows the otherwise packed ribcage "to move as the whale breathes and also accommodates changes in volume that occur as the air is compressed by water pressure when the whale dives through deep water."

Rommel added that the ribs' wide, flattened structure has only been observed before in certain types of anteaters. Studies on anteater ribs have indicated that the rib arrangement helps to stiffen their bodies as well.

"So, possibly, a stiffer body has advantages in the way (pygmy right whales) swim, but this is purely speculative at the moment," he said.

Keig also mentioned that two ribs from the upper ribcage broke, and then roughly healed, sometime during the 7.5-foot-long infant whale's short life. She suspects they broke when the six-month-old whale was stranded at Spirit's Bay in northern New Zealand, where it eventually died.

"We do not know the exact cause of death because our scientists performed a necropsy and not an autopsy," she said. "There are many possible causes for stranding."

One possibility, for example, is that the young whale became weakened and disoriented by a bacterial infection.

Brian Beatty, an assistant professor of anatomy at the New York College of Osteopathic Medicine, recently conducted one of the largest ever studies of modern and fossil whalebones.

Beatty told Discovery News that the analysis of the pygmy right whale is important because this species "is an unusual animal," even among the already unusual baleens.

Baleen whales, as opposed to toothed whales, feed by filtering water across a large, comb-like baleen structure.

"Being such a rare animal and hardly understood in terms of its anatomy and histology, this new specimen will significantly add to our understanding of the relationships between the modern baleen whales," Beatty said.

Although the official necropsy on the whale has ended, Keig said Te Papa scientists are still stripping the bones of flesh and muscle. Eventually the skeleton will go on display at the museum.

SOURCE : Discovery News

Friday, May 23, 2008

Environmental Groups Win Protection for Polar Bear

Faced With Scientific Evidence on Global Warming, Court Order, and
Public Pressure, Government Grants Polar Bear Endangered Species Act Listing
Due to Global Warming

Center for Biological Diversity, Following a three-year legal battle to protect the polar bear from extinction due to global warming, three environmental groups won protection for the species with the announcement today that the U.S. Fish and Wildlife Service is listing the polar bear as a federally “threatened” species.

The decision was issued in response to a 2005 scientific petition from the Center for Biological Diversity, Greenpeace, and the Natural Resources Defense Council, and was required by a court order in a lawsuit brought by the groups to end the administration's delay in issuing a final Endangered Species Act listing decision.

While the polar bear listing is one of the administration's clearest acknowledgments to date of the urgent threat posed by global warming, the administration is simultaneously attempting to reduce the protections the bear will receive under the Act. It claims in the listing decision that federal agencies need not consider the impact of global warming pollution on the polar bear; it has also proposed a separate regulation reducing the protections the polar bear would otherwise receive.

“This decision is a watershed event because it has forced the Bush administration to acknowledge global warming's brutal impacts,” said Kassie Siegel, climate program director at the Center for Biological Diversity and lead author of the 2005 petition. “It’s not too late to save the polar bear, and we'll keep fighting to ensure that the polar bear gets the help it needs through the full protections of the Endangered Species Act. The administration's attempts to reduce protection to the polar bear from greenhouse gas emissions are illegal and won't hold up in court.”

Polar bears live only in the Arctic and are totally dependent on the sea ice for all their essential needs. Global warming is an overwhelming threat to the polar bear, which is already suffering starvation, drowning, and population declines as the sea ice melts away.

"The polar bear is already on thin ice. Protecting the polar bear under the Endangered Species Act is a major step forward, but the Bush administration has proposed using loopholes in the law to allow the greatest threat to the polar bear — global warming pollution — to continue unabated," said Andrew Wetzler, director of the Endangered Species Project at NRDC. “If the key threats to the polar bear are not addressed soon, zoos will be the only place our grandchildren will be able to see a polar bear.”

“The administration's inclusion of this language exempts the impact of global warming on the polar bear and would gut any protections the ruling would have provided,” said Melanie Duchin, global warming campaigner for Greenpeace USA in Alaska. “Global warming threatens polar bears with extinction, so to exempt global warming pollution from the formula for protecting the species violates the spirit and intent of the ESA.”

Each step in the listing process has required legal action to enforce the Endangered Species Act's deadlines for protecting species. The three groups first sued the Bush administration in December 2005 because the government had ignored their petition to protect the polar bear. As a result of that lawsuit, in February 2006 the U.S. Fish and Wildlife Service found that protection of polar bears "may be warranted," and commenced a full status review of the species. A settlement agreement in the case committed the Service to make the second of three required findings by December 27, 2006, at which time the administration announced the proposal to list the species as “threatened.” By law, the administration was required to make today's final listing decision within one year of the proposal, or by January 9, 2008. When the administration failed to comply with that deadline, the groups filed suit on March 10, 2008 to end the delay. On April 28, the District Court issued an order requiring the administration to issue a decision by May 15.

Scientists predicted and have now documented the grim impacts to polar bears as the Arctic warms rapidly. Shrinking sea ice drastically restricts polar bears' ability to hunt their main prey, ice seals. In the spring of 2006, scientists located the bodies of several bears that had starved to death. Reduced food availability due to global warming has also caused polar bears to resort to cannibalism off the north coast of Alaska and Canada. In September, the U.S. Geological Survey predicted that, based on polar bear distribution and current global warming projections, two-thirds of the world's polar bear population would likely be extinct by 2050, including all polar bears within the United States.

The Arctic melt is also outpacing predictions. September 2007 shattered all previous records for sea-ice loss when the Arctic ice cap shrank to a record 1 million square miles — equivalent to an area six times the size of California — below the average summer sea-ice extent of the past several decades, reaching levels not predicted to occur until mid-century. Scientists already predict that this year's sea-ice minimum could shatter the record set in 2007, and several leading scientists have now stated that the Arctic Ocean could be ice-free in the summer by 2012.

Listing the polar bear guarantees that federal agencies will be obligated to ensure that any action they authorize, fund, or carry out will not jeopardize polar bears' continued existence or adversely modify their critical habitat, and the U.S. Fish and Wildlife Service will be required to prepare a recovery plan for the polar bear, specifying measures necessary for its protection.

SOURCE : Center for Biological Diversity

At One Undersea Volcano, Star Heaven

Ray Lilley - Discovery News, Marine scientists surveying a large undersea mountain chain were amazed to find millions of tiny brittle stars swirling their arms to capture food in the undersea current.

Brittlestar City

An expedition by 19 scientists studied the geology and biology of eight Macquarie Ridge sea mounts. They are part of a string of underwater volcanoes -- dormant for millions of years -- that stretches 875 miles from south of New Zealand toward Antarctica.

The scientists also investigated the world's biggest ocean current -- the Antarctic Circumpolar Current -- amid expectations they would find evidence of climate change in the Southern Ocean.

While the expedition's cameras found a wide range of corals and a high density of cardinal fish, the vast collection of brittle stars was the highlight of the voyage.

"I've personally never seen anything like this -- all these animals, the sheer volume -- all waiting for food from the current," expedition member and marine biologist Mireille Consalvey said Monday. "It challenged what we as scientists thought we knew."

Expedition leader and marine biologist Ashley Rowden said brittle stars usually cover only slopes away from the top of the undersea mountains.

"It got us excited as soon as we saw it," Rowden said of the site, dubbed "Brittle Star City."

The animals are about 0.4 inch across, with arms about 2 inches long.

The expedition began March 26 and returned to port in New Zealand's capital Wellington on April 26.

Brittle stars, or ophiuroid ophiacantha, are Echinoderms, as are starfish -- meaning they have a five-part body structure. But they're otherwise not related to starfish.

Melbourne-based marine biologist Tim O'Hara, a brittle star specialist, said the vast collection of brittle stars, or ophiuroid ophiacantha, is "like a relic of ancient times."

"Normally fish would prey on them and eat them ... so for whatever reason there's a lack of fish predation there and it's seen this particular animal flourish," he said.

O'Hara, who was not part of the voyage, said the speed of the sea current in the area may partly explain why fish were not feeding on the tiny animals.

The Circumpolar Current merges the waters of the Atlantic, Indian and Pacific oceans and carries up to 150 times the volume of water flowing in all the world's rivers, oceanographer Mike Williams said.

Australian oceanographer Steve Rintoul, who was not involved in the expedition, said there have been few measurements of the Antarctic Circumpolar Current, which "strongly influences regional and global climate" by carrying vast amounts of water and heat across oceans.

Fewer than 200 of the world's estimated 100,000 sea mounts that rise more than a half a mile above the sea floor have been studied in any detail.

SOURCE : Discovery News

New Blood Test Reveals Risk For Metabolic Syndrome

University of Minnesota researchers have discovered that people with high oxidation levels of the low-density lipoprotein (LDL) particle that carries cholesterol throughout the blood are much more likely to develop metabolic syndrome -- which can lead to a considerably increased risk of developing heart disease.

Researchers measured oxidized LDL in more than 2,000 generally healthy people aged 33-45 (average age 40) in an ongoing study, called CARDIA. After deleting those with metabolic syndrome, they followed the remaining 1,889 for five years. Those with the highest levels of oxidized LDL had 3.5 times the risk of developing metabolic syndrome five years later.

These findings are especially important for prevention of heart disease since the participants in this study were relatively young and few had any signs of it. Although neither diet, physical activity, nor smoking were directly studied, this finding bolsters the belief that all of these lifestyle factors need attention from youth onward to prevent heart disease.

"Smoking is one of the most common sources of oxidative stress. Optimal diet and an active lifestyle can keep the antioxidant defense system in balance and prevent oxidized LDL from forming," said David Jacobs, Ph.D., principal investigator of the study, and a professor in the School of Public Health.

In some people, cholesterol in the blood tends to deposit on arterial walls, leading to a building of plaque that causes atherosclerosis. Atherosclerosis damages artery walls, impedes flow of blood, and eventually causes heart attack. But cholesterol is also an important component of all cell walls and is therefore central to life. So why does excess cholesterol in the blood have a bad effect on health, when cholesterol itself is a fundamental building block of life?

Because cholesterol is a fat (lipid) that does not dissolve in blood, the body has devised a system of enveloping cholesterol in protein to transport it. These small bodies found in the blood are called lipoprotein particles. Many scientists believe that oxidation of the lipoprotein particles that carry cholesterol in the blood may answer the question of why cholesterol does damage. Oxidation is necessary to processing of oxygen and fueling the body. However, free radicals, formed as a product of oxidation, can be dangerous.

While free radicals can be used by the body to fight bacterial infections, if they are not kept in tight balance they can damage important molecules in the body. In particular, LDL particles are highly prone to oxidative damage (oxidized LDL). LDL particles are constantly zipping in and out of arterial walls, delivering cholesterol for needed biologic functions. If oxidized, the particle has trouble leaving the arterial walls, white cells are called in to attack the "invader," and before long an atherosclerotic plaque is developing, with the ultimate risk of heart attack.

With collaborators from Belgium and South Korea, University of Minnesota researchers have provided new information about how the process works.

Metabolic syndrome is a constellation of factors that predisposes people to conditions such as heart disease and diabetes. It includes obesity, mild glucose abnormalities, elevated blood pressure, and adverse alterations in blood lipids. It is complementary to other heart disease risk factors, such as smoking. Those with metabolic syndrome are at considerably increased risk for heart disease.

The blood test for oxidized LDL was invented by the first author of the paper, Professor Paul Holvoet, Ph.D., of Katholieke Universiteit, Leuven, in Belgium.

"If LDL particles are severely damaged, the body recognizes them and excretes them. But minimal oxidation is not as easily recognized. The test we devised identifies minimally oxidized LDL particles, which we theorized were the ones that are most likely to be incorporated into atherosclerotic plaque and cause health problems," Holvoet said. "The finding that oxidized LDL relates particularly to metabolic syndrome advances our understanding of how the atherosclerotic process works."

This study was funded by the National, Heart, Lung, and Blood Institute of the National Institutes of Health in the United States, the Belgian government, a Belgian foundation, and the University of Minnesota School of Public Health.

SOURCE : University of Minnesota, ScienceDaily

Thursday, May 22, 2008

Ancient Amphibian: Debate Over Origin Of Frogs And Salamanders Settled With Discovery Of Missing Link

University of Calgary, The description of an ancient amphibian that millions of years ago swam in quiet pools and caught mayflies on the surrounding land in Texas has set to rest one of the greatest current controversies in vertebrate evolution. The discovery was made by a research team led by scientists at the University of Calgary.

The examination and detailed description of the fossil, Gerobatrachus hottoni (meaning Hotton's elder frog), proves the previously disputed fact that some modern amphibians, frogs and salamanders evolved from one ancient amphibian group called temnospondyls.

The discovery is described for the first time in the journal Nature.

"The dispute arose because of a lack of transitional forms. This fossil seals the gap," says Jason Anderson, assistant professor, University of Calgary Faculty of Veterinary Medicine and lead scientist in the study.

The Gerobatrachus fossil provides a much fuller understanding of the origin and evolution of modern amphibians. The skull, backbone and teeth of Gerobatrachus have a mixture of frog and salamander features--the fossil has two fused bones in the ankle, which is normally only seen in salamanders, and a very large tympanic ear (ear drum). It also has a lightly built and wide skull similar to that of a frog. Its backbone is exactly intermediate in number between the modern frogs and salamanders and more primitive amphibians.

The new fossil also addresses a controversy over molecular clock estimates, or the general time salamanders and frogs evolved into two distinct groups.

"With this new data our best estimate indicates that frogs and salamanders separated from each other sometime between 240 and 275 million years ago, much more recently than previous molecular data had suggested," says Robert Reisz, professor, University of Toronto Mississauga and second author on the paper.

Gerobatrachus was originally discovered in Texas in 1995 by a field party from the Smithsonian Institution that included the late Nicholas Hotton, for whom the fossil is named. It remained unstudied until it was "rediscovered" by Anderson's team. It took countless hours of work on the small, extremely delicate fossil to remove the overlying layers of rock and uncover the bones to reveal the anatomy of the spectacular looking skeleton.

"It is bittersweet to learn about frog origins in this Year of the Frog, dedicated to informing the public about the current global amphibian decline," continues Anderson. "Hopefully we won't ever learn about their extinction."

SOURCE : University of Calgary

500 Million Years Ago, Jellyfish Left Their Mark in Fine Sea Sediments

The Cambrian fossil jellyfish, left, shows similarity to the modern jellyfish.

Henry Fountain - The New York Times, Your average jellyfish washed up on a beach is hardly recognizable — just an amorphous blob, fast decomposing in the sun. (They don’t call them jellyfish for nothing.)

Which makes the discovery in Utah of four types of well-preserved fossil jellyfish from the Middle Cambrian period, half a billion years ago, all the more remarkable.

In a paper in the open-access online journal PLoS ONE, Paulyn Cartwright of the University of Kansas and colleagues report that these are the oldest jellyfish fossils yet described, by about 200 million years.

The fossils were found in the Marjum Formation in the west-central part of the state. During the Cambrian period, what is now Utah was covered in warm shallow seas, so fossils of many ancient marine organisms are found there. But such well-preserved specimens of soft creatures like jellyfish are uncommon. What helped in this case was that they were compressed into very fine sediment, preserving images of what appear to be tentacles and even some internal features.

Some of those features, the researchers say, are comparable to modern ones, suggesting that jellyfish had already diversified greatly by 500 million years ago. It is not known whether they diversified quickly or got their start long before the Middle Cambrian.

SOURCE : The New York Times

Wednesday, May 21, 2008

Tasmanian Devil Endangered as Cancer Hits

Discovery News, Australia's Tasmanian devil will be listed as an endangered species this week as a result of a deadly and disfiguring cancer outbreak, the state government said Monday.

The disease, a fast-growing head tumor which spreads over the marsupial's face and mouth and prevents it from eating, often killing it within months, has cut the island's devil population in the wild by as much as 60 percent.

A spokeswoman for Tasmania's Primary Industries Minister David Llewellyn said the small, black-haired animal would be listed as an endangered species by state officials on Wednesday.

The minister told the Australian Broadcasting Corporation that the animal would be upgraded from a vulnerable to an endangered species so that the "appropriate resources and effort" can be poured into protecting it.

Photo by: Tim Dub

The government has also backed a plan to build an "insurance population" of healthy Tasmanian devils at wildlife reserves, zoos and other protected areas.

"If required, these animals could be utilized to help re-establish Tasmanian devil numbers in the wild," Llewellyn said.

The facial tumor is extremely unusual in that it is a contagious cancer, spread from devil to devil by biting.

The devil is the world's largest marsupial carnivore and now only lives in Australia's southern island state.

Early European settlers named the feisty marsupial the devil for its spine-chilling screeches, dark appearance and reputed bad temper which, along with its steeltrap jaw, made it appear incredibly fierce.

SOURCE : Discovery News

Tuesday, May 20, 2008


University of Minnesota,
University of Minnesota researchers show that adult bone marrow stem cells can be induced to differentiate into cells of the midbrain. The findings, published in the online early edition of the Proceedings of the National Academy of Sciences, suggest that adult bone-marrow-derived stem cells may one day be useful for treating diseases of the central nervous system, including Parkinson's disease.

The potential of these adult stem cells, termed multipotent adult progenitor cells (MAPCs), were the subject of research reported in Nature in June 2002. Today's published research findings show specific cell differentiation for a specific goal. While this type of cell differentiation has been shown to occur from embryonic and neural stem cells, this is the first time adult bone-marrow-derived cells have been shown to generate dopamine like neurons.

"We're able to show in vitro generation of functional dopamine producing cells from adult bone marrow stem cells needed for therapy of Parkinson's,"said lead investigator Catherine Verfaillie, M.D., director of the university's Stem Cell Institute. "This further proves similarity of the MAPCs with embryonic stem cells.

"Again, while adult stem cells hold great promise, side by side comparison of adult and embryonic stem cells must be done to determine which stem cells are most useful in treating a particular disease," said Verfaillie.

SOURCE : University of Minnesota

Monday, May 19, 2008

U-M researchers involved in oldest European human fossil find

University of Michigan - researcher Josep M. Pares,
is part of a team that has discovered the oldest known remains of human ancestors in Western Europe.

The find shows that members of the genus Homo, to which modern humans belong, colonized the region much earlier than previously believed. Details of the discovery were published in the
March 27 issue of the journal Nature.

The fossil—a small piece of jawbone with a few teeth—was found last year in a cave in the mountains of northern Spain, along with primitive stone tools and bones of animals that appear to have been butchered. The team, led by Spanish researchers Juan Luis Arsuaga, José María Bermúdez de Castro and Eudald Carbonell, used three separate techniques (including paleomagnetic analyses performed by Pares) to determine that the fossil is about 1.2 million years old. That's 500,000 years older than the previous oldest known humanlike fossils from the area. The new find bolsters the view that Homo reached Europe not long after leaving Africa almost 2 million years ago.

"It seems probable that the first European population came from the region of the Near East, the true crossroads between Africa and Eurasia, and that it was related to the first demographic expansion out of Africa," said Pares, who is a research scientist in the U-M Department of Geological Sciences and program director of the newly created National Research Center on Human Evolution (CENIEH) in Burgos, Spain, with which most of the authors are affiliated.

The researchers tentatively classified the new fossil as an earlier example Homo antecessor (Pioneer Man), the species represented by the previous oldest fossils and thought to be the last common ancestor of Neanderthals and modern humans.

"This is a very significant advance toward a better understanding of the nature, age and protagonists of the first European human settlement," Pares said.

SOURCE : University of Michigan

Sunday, May 18, 2008

Compound Has Potential For New Class Of AIDS Drugs

University of Michigan, Researchers have developed what they believe is the first new mechanism in nearly 20 years for inhibiting a common target used to treat all HIV patients, which could eventually lead to a new class of AIDS drugs.

Researchers at the University of Michigan used computer models to develop the inhibiting compound, and then confirmed in the lab that the compound does indeed inhibit HIV protease, which is an established target for AIDS treatment. The protease is necessary to replicate the virus, says Heather Carlson, U-M professor of medicinal chemistry and principal investigator of the study.

Carlson stresses this is a preliminary step, but still significant.

"It's very easy to make an inhibitor, (but) it's very hard to make a drug," said Carlson, who also has an appointment in chemistry. "This compound is too weak to work in the human body. The key is to find more compounds that will work by the same mechanism."

What's so exciting is how differently that mechanism works from the current drugs used to keep the HIV from maturing and replicating, she says. Current drugs called protease inhibitors work by debilitating the HIV-1 protease. This does the same, but in a different way, Carlson says.

A protease is an enzyme that clips apart proteins, and in the case of HIV drugs, when the HIV-1 protease is inhibited it cannot process the proteins required to assemble an active virus. In existing treatments, a larger molecule binds to the center of the protease, freezing it closed.

The new mechanism targets a different area of the HIV-1 protease, called the flap recognition pocket, and actually holds the protease open. Scientists knew the flaps opened and closed, but didn't know how to target that as a mechanism, Carlson says.

Carlson's group discovered that this flap, when held open by a very small molecule—half the size of the ones used in current drug treatments—also inhibits the protease.

In addition to a new class of drugs, the compound is key because smaller molecules have better drug-like properties and are absorbed much more easily.

"This new class of smaller molecules could have better drug properties (and) could get around current side effects," Carlson said. "HIV dosing regimes are really difficult. You have to take medicine several times in the day. Maybe you wouldn't have to do that with these smaller molecules because they would be absorbed differently."

Kelly Damm, a former student and now at Johnson & Johnson, initially had the idea to target the flaps in this new way, Carlson says.

"In a way, this works like a door jam. If you looked only at the door when it's shut, you'd not know you could put a jam in it," she said. "We saw a spot where we could block the closing event, but because everyone else was working with the closed form, they couldn't see it."

SOURCE : University of Michigan

Saturday, May 17, 2008

Dinosaur Bones Reveal Ancient Bug Bites

Jessica Witt - Brigham Young University, Paleontologists have long been perplexed by dinosaur fossils with missing pieces – sets of teeth without a jaw bone, bones that are pitted and grooved, even bones that are half gone. Now a Brigham Young University study identifies a culprit: ancient insects that munched on dinosaur bones.

BYU professor Brooks Britt will publish his study of these dinosaur bone-eating bugs in the May 8 issue of the scientific journal Ichnos. Britt’s idea for this study came when he first noticed the unique markings on the bones as an undergraduate at BYU.

“As students we noticed these marks and thought it might be due to algae or insects and we started calling them ‘bug bites,’ just for fun,” Britt said.

Years later, current BYU student Anne Dangerfield also wondered about the markings and teamed up with Britt to investigate the cause. They studied insect traces on the 148-million-year-old remains of a Camptosaurus, a plant-eating specimen discovered in Medicine Bow, Wyo., in 1995.

“I knew this trace was something different because I had been looking at fossil termite traces all summer, so I knew we needed to check it out,” Dangerfield said.

Their analysis revealed that beetles, from the family entomologists call Dermestidae, left the markings on the Camptosaurus. Dermestid beetles still exist today and are typically brown or black, oval-shaped and feed on flesh, hair, skin or horns of carcasses.

Information about the beetle’s typical habitat reveals the climate at the time of the Camptosaurus’ death probably had 60-80 percent relative humidity and a temperature of 77-86 F. By comparison, the average yearly temperature in Medicine Bow is now 43.5 F.

When the dinosaur died near what is now Medicine Bow, the carcass was consumed by other insects. The beetles then infested the Camptosaurus within months of its death.

In addition to shedding light on Wyoming’s ancient climate, Dangerfield and Britt’s work shows dermestid beetles existed much earlier than previously thought. The traces on this Camptosaurus predate the oldest body fossils for dermestid beetles by 48 million years.

“This information gives us an idea of the environment during the Jurassic period and the evolution of insects,” Dangerfield said.

To analyze the markings on the bones, Britt went to his family dentist for molding materials, allowing Britt to more quickly create replicas of the bone traces to work with.

He took the castings back to BYU’s Earth Science Museum where he used an electron microscope to look at the mandible markings in the bone, analyzing eating patterns and the width between the teeth marks. Britt and Dangerfield compared the marks to information about the mandibles of moths, termites, mayflies and dermestid beetles – all known to consume bone – to determine the identity of the insect.

“Other people have thought they have seen dermestid beetle marks, or they have interpreted termite marks as dermestids, but this paper provides a guide to identifying insects from the bone traces,” Britt said.

Britt and Dangerfield continued their research by looking at more than 7,000 bones from various quarries and found that insect traces on dinosaur bones are quite common, but dermestid beetle traces were found only on the Camptosaurus skeleton from Medicine Bow.

“Dr. Britt’s work is really exciting and delves into unique aspects of paleobiology that few scientists have yet explored,” said Eric Roberts, an expert in dinosaur decomposition who teaches at South Africa’s University of the Witwatersrand. “Insects are among the most diverse and abundant organisms on the planet, yet we know next to nothing about the fossil record of insects because of their extremely limited preservation potential.”

Dangerfield’s undergraduate and graduate mentored research experience has impressed many potential employers. After finishing her master’s degree in August, she will assume a position with Exxon Mobile as an exploration oil and gas geologist.

“Whenever I show my resume, employers are impressed with the amount of undergraduate research I’ve done,” Dangerfield said.

Britt received his bachelor’s and master’s degrees at BYU and his Ph.D. at the University of Calgary and is an assistant professor. Rodney Scheetz, another author on the study, is the curator at BYU’s Earth Science Museum.

SOURCE : Brigham Young University