February 5, 2010, 8:02 AM CT

Egyptian fruit bat finds a target

New research conducted at the University of Maryland's bat lab shows Egyptian fruit bats find a target by NOT aiming their guiding sonar directly at it. Instead, they alternately point the sound beam to either side of the target. The new findings by scientists from Maryland and the Weizmann Institute of Science in Israel suggest that this strategy optimizes the bats' ability to pinpoint the location of a target, but also makes it harder for them to detect a target in the first place.

"We believe that this tradeoff between detecting a object and determining its location is fundamental to any process that involves tracking an object whether done by a bat, a dog or a human, and whether accomplished through hearing, smell or sight," said coauthor Cynthia Moss, a University of Maryland professor of psychology, who directs interdisciplinary bat echolocation research in the university's Auditory Neuroethology Lab, better known as the bat lab.

Moss, colleagues Nachum Ulanovsky and Yossi Yovel of the Weizmann Institute, and Ben Falk, a graduate student of Moss's in Maryland's Neuroscience and Cognitive Science Program, published their findings in this week's edition of the journal Science. Ulanovsky, the paper's corresponding author, was a Maryland postdoctoral student under Moss......... Posted by: Kelly      Read more         Source

February 4, 2010, 8:22 AM CT

Viagra enhances fetal growth in female sheep

A joke among two Texas AgriLife Research researchers later turned into a fully-funded study found Viagra can aid fetal development in female sheep. Female sheep (ewes) are an agriculturally important species, which can serve as an excellent animal model for studying the physiology of human pregnancy, the scientists said.

Viagra (sildenafil citrate), which is used to treat male erectile dysfunction, enhanced blood flow in pregnant female sheep, helping send vital amino acids and other nutrients needed in fetal development. The study's results not only will assist with solving fetal development problems in other livestock, but possibly in humans, said Dr. Guoyao Wu, AgriLife Research animal nutritionist and Senior Faculty Fellow in the Department of Animal Science at Texas A&M University.

"Because 5 percent to 10 percent of infants are born as low birth-weight babies worldwide, and because fetal-growth retardation is also a significant problem in livestock species, our findings have important implications for both human health and animal agriculture," Wu said.

The findings are published in a recent edition of The Journal of Nutrition (http://www.nutrition.org/).

The study originated in 2003 after a chat between Wu and fellow AgriLife Research scientist Dr. Tom Spencer when they were working with pregnant ewes......... Posted by: Kelly      Read more         Source

February 3, 2010, 7:41 AM CT

Ancient crocodile likely food source for Titanoboa

A 60-million-year-old relative of crocodiles described this week by University of Florida scientists in the Journal of Vertebrate Paleontology was likely a food source for Titanoboa, the largest snake the world has ever known.

Working with researchers from the Smithsonian Tropical Research Institute in Panama, paleontologists from the Florida Museum of Natural History on the UF campus found fossils of the new species of ancient crocodile in the Cerrejon Formation in northern Colombia. The site, one of the world's largest open-pit coal mines, also yielded skeletons of the giant, boa constrictor-like Titanoboa, which measured up to 45 feet long. This is the first reported study of a fossil crocodyliform from the same site.

"We're starting to flesh out the fauna that we have from there," said main author Alex Hastings, a graduate student at the Florida Museum and UF's department of geological sciences.

Specimens used in the study show the new species, named Cerrejonisuchus improcerus, grew only 6 to 7 feet long, making it easy prey for Titanoboa. Its scientific name means small crocodile from Cerrejon.

The findings follow another study by scientists at UF and the Smithsonian providing the first reliable evidence of what Neotropical rainforests looked like 60 million years ago......... Posted by: Kelly      Read more         Source

February 1, 2010, 7:54 AM CT

New light on our earliest fossil ancestry

Decaying corpses are commonly the domain of forensic scientists, but palaeontologists have discovered that studying rotting fish sheds new light on our earliest ancestry.

The researchers, from the Department of Geology at the University of Leicester, devised a new method for extracting information from 500 million year old fossils -they studied the way fish decompose to gain a clearer picture of how our ancient fish-like ancestors would have looked. Their results indicate that some of the earliest fossils from our part of the tree of life may have been more complex than has previously been thought.

Their findings have been published recently, Sunday Jan 31, ahead of print in Advance Online Publication (AOP) of the science journal Nature on www.nature.com The work was funded by the Natural Environment Research Council (NERC).

Dr Rob Sansom, main author of the paper explains: "Interpreting fossils is in some ways similar to forensic analysis we gather all the available clues to put together a scientific reconstruction of something that happened in the past. Unlike forensics, however, we are dealing with life from millions of years ago, and we are less interested in understanding the cause or the time of death. What we want to get at is what an animal was like before it died and, as with forensic analysis, knowing how the decomposition that took place after death altered the body provides important clues to its original anatomy."........ Posted by: Kelly      Read more         Source

January 29, 2010, 8:07 AM CT

Bees recognize human faces

Going about their day-to-day business, bees have no need to be able to recognise human faces. Yet in 2005, when Adrian Dyer from Monash University trained the fascinating insects to associate pictures of human faces with tasty sugar snacks, they seemed to be able to do just that. But Martin Giurfa from the Universit de Toulouse, France, suspected that that the bees weren't learning to recognise people. 'Because the insects were rewarded with a drop of sugar when they chose human photographs, what they really saw were strange flowers. The important question was what strategy do they use to discriminate between faces,' explains Giurfa. Wondering whether the insects might be learning the relative arrangement (configuration) of features on a face, Giurfa contacted Dyer and suggested that they go about systematically testing which features a bee learned to recognise to keep them returning to Dyer's face photos. The team publish their discovery that bees can learn to recognise the arrangement of human facial features on 29 January 2010 in the Journal of Experimental Biology at http://jeb.biologists.org.

Teaming up with Aurore Avargues-Weber, the team first tested whether the bees could learn to distinguish between simple face-like images. Using faces that were made up of two dots for eyes, a short vertical dash for a nose and a longer horizontal line for a mouth, Avargues-Weber trained individual bees to distinguish between a face where the features were cramped together and another where the features were set apart. Having trained the bee to visit one of the two faces by rewarding it with a weak sugar solution, she tested whether it recognised the pattern by taking away the sugar reward and waiting to see if the bee returned to the correct face. It did......... Posted by: Kelly      Read more         Source

January 28, 2010, 8:07 AM CT

Figs and fig wasps

Figs and fig wasps have evolved to help each other out: Fig wasps lay their eggs inside the fruit where the wasp larvae can safely develop, and in return, the wasps pollinate the figs.

But what happens when a wasp lays its eggs but fails to pollinate the fig?

The trees get even by dropping those figs to the ground, killing the baby wasps inside, reports a Cornell University and Smithsonian Tropical Research Institute study reported in the Proceedings of the Royal Society B (published online Jan. 13).

The findings suggest that when one species in a mutually beneficial relationship fails to hold up its end of the bargain, sanctions appears to be a necessary part of maintaining the relationship.

"We want to know what forces maintain this 80 million-year-old mutualism between figs and their wasp pollinators," said main author Charlotte Jandr, a Cornell graduate student in neurobiology and behavior, who conducted the study as a Smithsonian Tropical Research Institute predoctoral fellow. Edward Allen Herre, a staff scientist at the Smithsonian institute in Panama, co-authored the paper.

"What prevents the wasps from cheating and reaping the benefits of the relationship without paying the costs?" Jandr added.

More than 700 species each of fig trees and wasps have co-evolved in the tropics worldwide, with each fig tree species having its own species of pollinating wasp. Jandr worked on six fig tree-fig wasp pairs for the study. Some wasp species passively carry pollen that sticks to their bodies, while others actively collect pollen in special pouches......... Posted by: Kelly      Read more         Source

January 28, 2010, 8:02 AM CT

Deadly fish virus now found in all Great Lakes

A deadly fish virus that was first discovered in the Northeast in 2005 has been found for the first time in fish from Lake Superior, report Cornell researchers. That means that the virus has now been documented in all of the Great Lakes.

The viral hemorrhagic septicemia virus (VHSV), which causes fatal anemia and hemorrhaging in a number of fish species, poses no threat to humans, said Paul Bowser, professor of aquatic animal medicine at Cornell's College of Veterinary Medicine.

Bowser and his colleagues recently tested 874 fish from seven sites in Lake Superior in collaboration with the U.S. Geological Survey (USGS) Western Fisheries Research Center in Seattle. Fish from Paradise and Skanee in Michigan and St. Louis Bay and Superior Bay in Wisconsin tested positive. Some of the results have been corroborated by other laboratories; others have tests still under way.

The virus, which has been identified in 28 freshwater fish species in the Great Lakes watershed, has reached epidemic proportions in the Great Lakes and threatens New York's sport-fishing industry, said Bowser, estimated to contribute some $1.4 billion annually to New York's economy.

"People come from all over the eastern United States to fish the Great Lakes," said Bowser, noting that the virus has also been found in a few inland waters as well, including lakes, streams and a family-owned earthen pond. "The economy of a number of of these areas ebbs and flows with the season and perceived value of outdoor recreational opportunities. The value of these opportunities is dependent on how successful we are at managing the health of wild fish. On a worldwide basis, VHSV is considered one of the most serious pathogens of fish, because it kills so a number of fish, is not treatable and infects a broad range of fish species"......... Posted by: Kelly      Read more         Source

January 27, 2010, 8:19 AM CT

The Low Calorie Pet Foods

Dog and cat owners buying weight-control diets for their overweight pets are faced with a confusing two hundred percent variation in calorie density, recommended intake, and wide range cost of low-calorie pet foods, as per a research studyby the Cummings School of Veterinary Medicine at Tufts University.

The study, published this month in the Journal of the American Veterinary Medical Association, examined nearly 100 commercially available diets with weight management claims. Among their findings is that dry dog foods range in calorie density from 217 to 440 kilocalories per cup (kcal/cup) and a recommended intake that ranged from 0.73 to 1.47 times the dog's resting energy requirement. The diets also varied wildly in price-from 4 cents to more than $1.10 per kilocalorie.

Similar findings were made in wet dog food (189-398 kcal/can) and cat food (235-480 kcal/cup) marketed for weight control. The results appears to be significant for owners whose cats or dogs are overweight or obese, as per Lisa M. Freeman, DVM, PhD, DACVN, the study's co-author along with 2010 Cummings School graduate Deborah E. Linder, DVM. Nearly 50% of domesticated animals are overweight or obese.

"There is so much information-and misinformation-about pet foods, it's understandable that people are confused about what to feed their dogs and cats," said co-author Dr. Lisa Freeman, professor of nutrition at Tufts University's Cummings School of Veterinary Medicine. "To counteract these myths, people are accustomed to turning to the labels on food-but, as this study shows, packaging might not always be a reliable source of information"......... Posted by: Kelly      Read more         Source

January 27, 2010, 8:14 AM CT

Environmental threats to blue crabs

The Atlantic blue crab, Callinectes sapidus, long prized as a savory meal at a summer party or seafood restaurant, is a multi-million dollar source of income for those who harvest, process and market the crustacean along the U.S. Atlantic and Gulf coasts. Unfortunately, the blue crab population has been declining in recent years under the assault of viruses, bacteria and man-made contaminants. The signs of the attack often are subtle, so scientists from the National Institute of Standards and Technology (NIST) and the College of Charleston (CofC) are at work trying to identify the clues that will finger specific, yet elusive, culprits.

Pathogens and pollutants impair the blue crab's metabolic processes, the chemical reactions that produce energy for cells. These stresses should cause tell-tale changes in the levels of metabolites, small chemical compounds created during metabolism. Working at the Hollings Marine Laboratory (HML) in Charleston, S.C., the NIST/CofC research team is using a technology similar to magnetic resonance imaging (MRI) to identify and quantify the metabolites that increase in quantity under common environmental stresses to blue crabsmetabolites that could be used as biomarkers to identify the specific sources.

In a recent paper in Metabolomics,* the HML research team describes how it used nuclear magnetic resonance (NMR) spectroscopy to study challenges to one specific metabolic process in blue crabs: oxygen uptake. First, the scientists simulated an environmentally acquired bacterial infection by injecting crabs with the bacterium Vibrio campbellii. This pathogen impairs the crab's ability to incorporate oxygen during metabolism. Using NMR spectroscopy to observe the impact on metabolite levels, the scientists observed that the yield of glucose, considered a reliable indicator of mild oxygen starvation in crustaceans, was raised......... Posted by: Kelly      Read more         Source

January 25, 2010, 8:04 AM CT

Bat researchers no longer flying blind

Scientists at The University of Western Ontario (Western) led an international and multi-disciplinary study that sheds new light on the way that bats echolocate. With echolocation, animals emit sounds and then listen to the reflected echoes of those sounds to form images of their surroundings in their brains.

The team used state-of-the-art micro-computed tomography systems at the Robarts Research Institute in London, Ontario to collect detailed 3D scans of the internal anatomy of 26 different bats, representing 11 different evolutionary lineages. This non-destructive technique allowed scientists to identify a bone that connects the larynx to the bones that surround and support the eardrum in bats. Some bats use their larynx to generate echolocation (biosonar) signals, allowing them to operate at night; other bats use tongue clicks to achieve the same purpose.

The research team discovered that the correlation between the larynx and the ear via the stylohyal bone in the hyoid chain was unique to bats that used laryngeal echolocation. This observation makes it possible to distinguish bats that produce echolocation signals with their larynx from bats that do not echolocate and those that use tongue clicks. The results of the research will appear this week in the journal Nature, entitled "A Bony Connection Signals Laryngeal Echolocation in Bats"......... Posted by: Kelly      Read more         Source

January 25, 2010, 0:04 AM CT

Risky business for toads under threat from fungus

Midwife toads that live in the mountains are highly likely to die from a serious fungal infection, called chytridiomycosis, whereas their infected relatives in the lowlands are not, as per new research published recently in Ecology Letters

The authors of the study, from Imperial College London, the Zoological Society of London and the BiodivERsA project RACE, say their findings suggest conservationists appears to be able to limit the impact of the disease in the mountains by ensuring tourists do not transfer it between lakes.

During the five year study, the scientists observed that no midwife toads at low altitudes died as a result of fungal infection, whereas up to 100 per cent of those at high altitudes died. The mortality rate of toads at high altitudes fluctuated over the five years.

The fungus Batrachochytrium dendrobatidis (Bd), also known as chytrid fungus, grows in the skin of amphibians, causing a disease called chytridiomycosis. The fungus has caused a number of species of frog and toad to become extinct and human activity has spread the fungus across the world, affecting an estimated 50 per cent of amphibian species.

Eventhough infection commonly is invisible to the naked eye, it can cause skin discolouration and ulceration and lead to convulsions. Prior research shows that infection kills amphibians by causing heart failure. The fungus is especially prevalent in Australia and the Americas, where its spread is well studied. However, little was known about Bd in Europe before today's study......... Posted by: Kelly      Read more         Source

Mon, 25 Jan 2010 05:35:42 GMT

Parasite of the Day

My colleague at the American Museum of Natural History, Susan Perkins, has started an ambitious new blog. She will be introducing a new parasite to the world each day in Parasite of the Day. Unfortunately, perhaps, for the hosts of the world, Susan has plenty of subject matter and should be busy for quite some time. A recent paper in PNAS (Dobson et al. 2008) states that although they "estimate that there are between 75,000 and 300,000 helminth species parasitizing the vertebrates. [They] have no credible way of estimating how many parasitic protozoa, fungi, bacteria, and viruses exist. At least the helminths parasites of vertebrates will keep Susan busy for the next 821 years or so.
The photo above is of Neoechinorhynchus emyditoides a species of acanthocephalan, or thorny-headed worm, by Mike Barger. Posted by: Dennehy      Read more     Source

Mon, 25 Jan 2010 05:05:52 GMT

Andrew Zuckerman's Bird

Turning his camera to the world of birds, Andrew Zuckerman has created a new body of work showcasing more than 200 stunning photographs of nearly 75 different species.



(via Neatorama) Posted by: Gerard      Read more     Source

January 22, 2010, 8:05 AM CT

Sexual reproduction versus asexual reproduction

Living organisms have good reason for engaging in sexual, rather than asexual, reproduction as per Maurine Neiman, assistant professor of biology in the UI College of Liberal Arts and Sciences and researcher in the Roy J. Carver Center for Genomics.

In an article published in a recent issue of the journal Molecular Biology and Evolution, she and her colleagues, including John M. Logsdon Jr., associate professor of biology, examined the theory that sexual reproduction, while requiring more time and energy than asexual reproduction, is also much more common among living organisms and, therefore, must be very beneficial.

The study looked at sexual, as well as asexual, varieties of a New Zealand freshwater snail (left), Potamopyrgus antipodarum, by sequencing mitochondrial genomes and observed that the sexually reproducing snails had accumulated harmful DNA mutations at about half the rate of the asexual snails.

"This is the first study to compare mutation accumulation in a species where sexual individuals and asexual individuals regularly coexist, and thus provides the most direct evidence to date that sex helps to counter the accumulation of harmful mutations," said Neiman.

Neiman plans to continue her evolutionary biology research such that a clearer understanding of the advantages of sex will offer a better understanding of the value of preserving genetic diversity within and among populations, species, and ecological communities......... Posted by: Kelly      Read more         Source

January 22, 2010, 8:03 AM CT

Zebrafish helps drug development

By combining the tools of medicinal chemistry and zebrafish biology, a team of Vanderbilt researchers has identified compounds that may offer therapeutic leads for bone-related diseases and cancer.

The findings, reported in ACS Chemical Biology, support using zebrafish as a novel platform for drug development.

In 2007, Charles Hong, M.D., Ph.D., and his colleagues described using fish embryos to screen for compounds that interfere with signaling pathways involved in early development pathways known to play roles in a variety of disease processes. They discovered the compound "dorsomorphin" and demonstrated that it blocked BMP (bone morphogenetic protein) signaling, which has been implicated in anemia, inflammatory responses and bone-related disorders.

But in examining dorsomorphin further, the researchers observed that it had other "off-target" effects it also blocked the VEGF (vascular endothelial growth factor) receptor and disrupted zebrafish blood vessel development, a process called angiogenesis.

"Off-target effects contribute to side effects and limit the therapeutic potential of small molecule signaling inhibitors," said Hong, assistant professor of Medicine and Pharmacology.

To find compounds that were more selective BMP inhibitors (didn't have the off-target effects), Hong and his colleagues opted to use their zebrafish drug discovery screen as a drug development/optimization tool......... Posted by: Kelly      Read more         Source

Mon, 18 Jan 2010 05:43:20 GMT

Green Sea Slug Is Part Animal, Part Plant

It"s easy being green for a sea slug that has stolen enough genes to become the first animal shown to make chlorophyll like a plant. Shaped like a leaf itself, the slug Elysia chlorotica already has a reputation for kidnapping the photosynthesizing organelles and some genes from algae.

Now it turns out that the slug has acquired enough stolen goods to make an entire plant chemical-making pathway work inside an animal body. The slugs can manufacture the most common form of chlorophyll, the green pigment in plants that captures energy from sunlight. Posted by: Gerard      Read more     Source

January 15, 2010, 8:09 AM CT

Plant-pollinator relationship

Figs and the wasps that pollinate them present one of biologists' favorite examples of a beneficial relationship between two different species. In exchange for the pollination service provided by the wasp, the fig fruit provides room and board for the wasp's developing young. However, wasps do not always pollinate the fig. Fig trees "punish" these "cheaters" by dropping unpollinated fruit, killing the wasp's offspring inside, report scientists working at the Smithsonian Tropical Research Institute.

Their results, reported in the Proceedings of the Royal Society, show that sanctions against cheaters appears to be critical to maintain the relationship.

"Relationships require give and take. We want to know what forces maintain this 80-million-year-old arrangement between figs and their wasp pollinators." said main author, Charlotte Jandr, graduate student in Cornell University's Department of Neurobiology and Behavior, who conducted the study as a Smithsonian pre-doctoral fellow. "What prevents the wasps from reaping the benefits of the relationship without paying the costs?".

Some wasp species passively carry pollen that sticks to their bodies. Others actively collect pollen in special pouches. Jandr reviewed the ability of six different fig tree-fig wasp species pairs to regulate cheating. She introduced either a single pollen-free wasp, or a wasp carrying pollen, into a mesh bag containing an unpollinated fig. The wasps entered the figs to lay their eggs. Jandr observed that trees often dropped unpollinated figs before young wasps could mature......... Posted by: Kelly      Read more         Source

January 14, 2010, 8:11 AM CT

Why leopards can't change their spots

The leopard cannot change its spots, nor can the tiger change its stripes, but a new research report reported in the January 2009 issue of the journal GENETICS tells us something about how cats end up with their spots and stripes. It demonstrates for the first time that at least three different genes are involved in the emergence of stripes, spots, and other markings on domestic cats. Scientists have also determined the genomic location of two of these genes, which will allow for further studies that could shine scientific light on various human skin disorders.

"We hope that the study opens up the possibility of directly investigating the genes involved in pattern formation (i.e., the establishment of stripes, spots, and other markings) on the skin of mammals, including their structure, function, and regulation," said Eduardo Eizirik, a researcher involved in the work from the Pontifical Catholic University of Rio Grande do Sul, Brazil. "From these studies, we hope to understand how the different coat patterns have evolved in different mammalian groups, and to be able to investigate their roles in adaptation to different environments, such as their importance for camouflage in wild cat species."

Researchers crossed domestic cats with different coat patterns, such as stripes and blotches, and tracked the inheritance of these patterns among their offspring. Genetic samples were collected and used to type various molecular markers. Results showed that specific markers were inherited by a kitten every time a given coat pattern appeared, suggesting that the marker and the gene causing the coat pattern were located in the same region of the genome. Using statistical procedures called linkage mapping, researchers determined the genomic location of two genes involved in these traits. By clarifying the inheritance of markings in one mammalian species, scientists hope to identify and characterize the implicated genes and then determine if they apply to other mammals, such as humans. The hope is that this discovery will shed new light on human skin diseases that appear to follow standardized patterns......... Posted by: Kelly      Read more         Source

January 14, 2010, 8:10 AM CT

Tracking paw prints of selective breeding

From the Dachshund's stubby legs to the Shar-Pei's wrinkly skin, breeding for certain characteristics has left its mark on the dog genome. Scientists have identified 155 regions on the canine genome that appear to have been influenced by selective breeding.

With more than 400 distinct breeds, dogs come in a wide range of shapes, sizes, fur-styles, and temperaments. The curly-haired toy poodle, small enough to sit in a teacup, barely looks or acts like the smooth-coated Great Dane tall enough to peer like a periscope out of a car's sunroof. Not so apparent are breed differences in how the dogs' bodies function and their susceptibility to various diseases.

Eventhough domestication of dogs began over 14,000 years ago, as per Dr. Joshua Akey, University of Washington (UW) assistant professor of genome sciences, the spectacular diversity among breeds is thought to have originated during the past few centuries through intense artificial selection of and strict breeding for desired characteristics. Akey is the main author of the effort to map canine genome regions that show signs of recent selection and that contain genes that are prime candidates for further investigation. Those genes are being examined for their possible roles in the most conspicuous variations among dog breeds: size, coat color and texture, behavior, physiology, and skeleton structure......... Posted by: Kelly      Read more         Source

January 13, 2010, 8:16 AM CT

Tilapia feed on Fiji's native fish

The poster child for sustainable fish farmingthe tilapiais actually a problematic invasive species for the native fish of the islands of Fiji, as per a newly released study by the Wildlife Conservation Society and other groups.

Researchers suspect that tilapia introduced to the waterways of the Fiji Islands appears to be gobbling up the larvae and juvenile fish of several native species of goby, fish that live in both fresh and salt water and begin their lives in island streams.

The recently published paper appears in Aquatic Conservation: Marine and Freshwater Ecosystems The authors include: Stacy Jupiter and Ingrid Qauqau of the Wildlife Conservation Society; Aaron P. Jenkins of Wetlands International-Oceania; and James Atherton of Conservation International.

"A number of of the unique freshwater fishes of the Fiji Islands are being threatened by introduced tilapia and other forms of development in key water catchment basins," said Dr. Jupiter, a co-author of the study and one of the researchers examining the effects of human activities on the native fauna. "Conserving the native fishes of the islands will require a multi-faceted collaboration that protects not only the waterways of the islands, but the ecosystems that contain them." .

The most surprising finding of the study centers on the tilapia, a member of the cichlid family of fishes from Africa that has become one of the most important kinds of fish for aquaculture, due in large part to its rapid rate of growth and palatability. Aside from its value as a source of protein, the tilapia is sometimes problematic to native fish species in tropical locations......... Posted by: Kelly      Read more         Source