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November 21, 2006, 5:13 AM CT

Clues From Dragonfly About Human Obesity

Clues From Dragonfly About Human Obesity Among dragonfly (Libellula pulchella) a supposedly harmless parasite triggers metabolic disorders similar to those found in humans afflicted with insulin resistance, type 2 diabetes and obesity.
Parasite-infected dragonflies suffer the same metabolic disorders that have led to an epidemic of obesity and type-2 diabetes in humans, reveal the findings of research conducted at Penn State University that are due would be published in the 5 December 2006 issue of the Proceedings of the National Academy of Science and also in the PNAS early online edition at www.pnas.org on 21 November. The discovery expands the known taxonomic breadth of metabolic disease and suggests that the study of microbes found in human intestines may provide a greater understanding of the root causes of human metabolic dysfunction.

James Marden, professor of biology and an insect physiologist at Penn State, and Ruud Schilder, who in August 2006 earned his doctorate in biology at Penn State and is now a postdoctoral fellow at the University of Nebraska, are the first to show a non-mammalian species suffering from metabolic dysfunction in ways similar to humans. "Metabolic disease isn't some strange thing having just to do with humans," said Marden. "Animals in general suffer from these symptoms".

The work is also novel because it links metabolic disease to a supposedly harmless parasite living in the dragonfly's gut. The parasites, known as gregarines, belong to the Apicomplexa, a group of microorganisms that includes protozoa, which cause diseases like malaria and cryptosporidiosis. The dragonfly species that Marden and Schilder studied is Libellula pulchella. The microbes disrupting the dragonfly metabolism may hold clues for scientists looking for the root causes of metabolic diseases in humans, according to Marden and Schilder's paper.........

Posted by: Kelly      Permalink         Source


November 20, 2006, 5:16 AM CT

Origins of Life

Origins of Life
The origin of life lies in unique ocean reefs, and researchers from the University of Miami's Rosenstiel School of Marine & Atmospheric Science have developed an approach to help investigate them better. A new article reported in the recent issue of Geology reveals how Dr. Miriam Andres' stromatolite investigation - the first of its kind - has begun to "fingerprint" ancient microbial pathways, increasing the understanding of how these reef-like structures form and offering a new way to explore the origins of these living records, which are considered to be the core of most living organisms.

Modern marine stromatolites are living examples of one of the earth's oldest and most persistent widespread ecosystems. Eventhough rare today, these layered deposits of calcium carbonate are found in shallow marine seas throughout 3.4 billion-year-old geologic records. Ancient stromatolites represent a mineral record of carbonate chemistry and the evolution of early life. In the Geology paper, Dr. Andres and his colleagues point out that incorrect assumptions have been made in interpreting stromatolite data: phototrophs, or oxygen-producers, were actually dominated by heterotrophs, or oxygen-consumers, in their contribution to stromatolite formation.

"The motivation for this study is that in ancient stromatolites, direct evidence of microbial activity is lacking," Dr. Andres explained. "Stable isotopes have provided a powerful tool to 'fingerprint' microbial pathways and better understand the sedimentary structures we see in the geologic record. Surprisingly, no study to date has documented this process for modern marine stromatolites."........

Posted by: Erica      Permalink         Source


November 20, 2006, 5:12 AM CT

Monarch Butterfly Migration And Forest Restoration

Monarch Butterfly Migration And Forest Restoration
USDA Forest Service (FS) research in the Ouachita Mountains of Arkansas suggests that decades of fire suppression have reduced the area's food supply for migrating monarch butterflies-and that restoration efforts that include prescribed burning can reverse this trend. Craig Rudolph and Ron Thill, research ecologists with the FS Southern Research Station (SRS), along with SRS ecologists Charles Ely, Richard Schaefer and J. Howard Williamson, report their findings in the latest issue of the Journal of the Lepidopterists' Society.

Every fall, masses of monarch butterflies migrate across eastern North America to remote sites in central Mexico-a long flight fuelled only by nectar from flowers still blooming on the way. In recent years, there have been concerns about the continued health of monarch populations, and of the migration itself, as land use change has altered both breeding habitat and migratory pathways.

Studies have focused on food availability for larvae, pesticides, and loss of overwintering sites in Mexico as possible threats. Less attention has been paid to how landscape-level changes affect the availability of the butterfly's preferred nectar sources along their migratory routes. In September and October, large numbers of monarchs pass through the Ouachita Mountains, a largely forested area in Arkansas and Oklahoma where fire suppression, logging, and pine production practices have altered forest structure, leading to a drastic reduction in the quality and abundance of the flowering plants the butterflies rely on for nectar.........

Posted by: Kelly      Permalink         Source


November 19, 2006, 9:30 PM CT

Wnt Reactivates Dormant Limb Regeneration

Wnt Reactivates Dormant Limb Regeneration
Chop off a salamander's leg and a brand new one will sprout in no time. But most animals have lost the ability to replace missing limbs. Now, a research team at the Salk Institute for Biological Studies has been able to regenerate a wing in a chick embryo a species not known to be able to regrow limbs - suggesting that the potential for such regeneration exists innately in all vertebrates, including humans.

Their study, reported in the advance online edition of Genes and Development on Nov. 17, demonstrates that vertebrate regeneration is under the control of the powerful Wnt signaling system: Activating it overcomes the mysterious barrier to regeneration in animals like chicks that can't normally replace missing limbs while inactivating it in animals known to be able to regenerate their limbs (frogs, zebrafish, and salamanders) shuts down their ability to replace missing legs and tails.

"In this simple experiment, we removed part of the chick embryo's wing, activated Wnt signaling, and got the whole limb back - a beautiful and perfect wing," said the lead author, Juan Carlos Izpisa Belmonte, Ph.D., a professor in the Gene Expression Laboratory. "By changing the expression of a few genes, you can change the ability of a vertebrate to regenerate their limbs, rebuilding blood vessels, bone, muscles, and skin - everything that is needed".........

Posted by: Janet      Permalink         Source


November 19, 2006, 9:01 PM CT

Which Wasps Are Bad Losers

Which Wasps Are Bad Losers Wasps fighting over larvae on which to lay their eggs release potent chemicals if they are defeated.
Wasps have more than just a sting in their tail as per new research published this week in the Proceedings of the Royal Society B, they also carry the insect version of pepper spray in their heads, which they can release when fighting other wasps. The research not only gives us a fascinating insight into insect behaviour but could also help us to use wasps to kill crop destroying pests.

For the first time scientists, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), have recorded 'chemical exchanges' undetectable by the human nose which take place between females of a species of bethylid wasp - Goniozus legneri, when they fight over larvae on which they lay their eggs. Not only have they discovered that chemical exchanges take place, but also that it is always the losing wasp that releases the potent gas.

While the research was primarily aimed at improving the understanding of animal behaviour, lead researcher Dr Ian Hardy, from the University of Nottingham, explains that there is great potential for applied spin-offs: "Bethylid wasps kill the larvae of a number of insects that are pests of crops, such as almonds, coffee and coconut, ruining harvests and costing industry thousands of pounds. These wasps could be used as a cheap and effective biological control to kill the larvae, avoiding the use of expensive and polluting pesticides. But for successful biological control, we need a good knowledge of wasp behaviour, including how wasps from the same and different species interact. Understanding these patterns can inform us of the best combinations of species to release against a given crop pest." .........

Posted by: Kelly      Permalink         Source


November 19, 2006, 8:57 PM CT

Fighting Like A Girl Or Boy

Fighting Like A Girl Or Boy Flies reading to fight
Fighting like a girl or fighting like a boy is hardwired into fruit fly neurons, as per a research studyin the Nov. 19 Nature Neuroscience advance online publication by a research team from Harvard Medical School and the Institute of Molecular Pathology in Vienna. The results confirm that a gene known as "fruitless" is a key factor underlying sexual differences in behavior. The findings mark a milestone in an unlikely new animal model for understanding the biology of aggression and how the nervous system gives rise to different behaviors.

"Aggression is a very serious problem in society, and it's a problem with a biological and genetic component," said co-author Edward Kravitz, the George Packer Berry professor of neurobiology at HMS, who developed the fruit fly fighting model used. "We want to understand that. I can't think of a better system to study than fruit flies. And no one gets hurt".

The fruitless gene is known for its role in male courtship. The large gene makes a set of male-specific proteins found exclusively in the nervous system of fruit flies, in about 2 percent of neurons. The proteins are necessary for normal courting. Males missing the proteins do not court females, and they sometimes court males, other research groups have shown. Females with a male version of the gene perform the male courting ritual with other females.........

Posted by: Kelly      Permalink         Source


November 16, 2006, 9:53 PM CT

Emperor Penguin Physiology

Emperor Penguin Physiology
Long before they lit up movie screens in animated feature films or enthralled documentary film audiences worldwide with the story of their endless struggle to survive and reproduce, Emperor penguins intrigued early Antarctic explorers.

As movie makers prepare this weekend to release "Happy Feet," about an animated Emperor who loves to dance, and the Hallmark Channel readies the cable-television premier of the documentary "March of the Penguins" on Sat., Nov. 25, 2006, the National Science Foundation (NSF) is making available B-roll of the penguins in Antarctica. The agency is also offering journalists the opportunity to ask Antarctic scientists questions about why the birds still challenge the scientific mind.

On the eve of International Polar Year (IPY), Emperor penguins, which can dive unharmed to depths that no human could survive unaided, still fascinate researchers.

By studying the animals' physiology and the way their bodies respond to the crushing pressure of deep dives, these NSF-funded scientists, who also are medical doctors, may one day provide clues to help improve surgical procedures and anesthesia. The study of Emperors also is very much in the spirit of NSF's IPY theme of attempting to understand what makes the processes of life in the cold and dark unique.........

Posted by: Kelly      Permalink         Source


November 16, 2006, 9:45 PM CT

Different Coat Color doesn't Mean Different Species

Different Coat Color doesn't Mean Different Species The mouse lemurs of Madagascar are the smallest known living primates (credit photo L.R. Godfrey)
Scientists have observed that lemurs suspected to belong to different species because of their strikingly different coat colors, are not only genetically alike, but belong to the same species.

Historically, species classification has been based on comparison of visible physical characteristics of plants or animals. Kellie Heckman, a post-doctoral fellow in ecology and evolutionary biology at Yale, and her colleagues at other universities, used analysis of a mitochondrial gene, cytochrome b, to test the genetic relationship of 70 lemurs that were believed to be long to up to three different species. Their report was reported in the open access journal BMC Evolutionary Biology.

"Our study combined morphological, genetic, geographic, and ecological data giving a multidimensional, and hopefully more accurate picture of species diversity," said Heckman. "Over the past decade, the number of proposed species of these lemurs has jumped from two to fifteen, based on physical differences. It pointed to the need for caution when identifying new species solely on the basis of visual or genetic characteristics."

The lemurs they tested had three extremely different coat colors and lived in different types of forest locations in southern Madagascar - classic characteristics of separate species. These scientists chose to compare mitochondrial cytochrome b as a gene marker that is known to change at a rate similar to that of speciation. Other common nuclear genes may evolve more slowly or more rapidly with population drift.........

Posted by: Kelly      Permalink         Source


November 16, 2006, 4:58 AM CT

Key To Controlling Gypsy Moth Spread

Key To Controlling Gypsy Moth Spread
Controlling population peaks on the edges of the gypsy moth range may help to slow their invasion into virgin territory, as per a team of researchers.

"Slowing the spread of the gypsy moth is a priority in forest management in the U.S.," says Ottar Bjornstad, associate professor of entomology and biology, Penn State. "Understanding the underlying patterns in the spread of invasive species is important for successful management".

The accidental release of the gypsy moth in 1869 in Massachusetts has led to an infestation covering more than 386,000 square miles of the U.S. Northeast. Native to Europe and Asia, gypsy moths are currently found from Maine to North Carolina and west into Wisconsin where they defoliate trees and occasionally, cause extensive damage to northern deciduous forests.

"We analyzed historical data on the spread of the gypsy moth in the U.S. and observed that its invasion has been characterized by regular periods of rapid spread interspersed between periods of little expansion," says Bjornstad. "This is the first identification of pulsed invasions for an invading species".

Bjornstad; Derek M. Johnson, Department of Biology, University of Louisiana, and Andrew M. Liebhold and Patrick C. Tobin, U.S. Forest Service, used historical, county-level quarantine records as well as forest service data from more than 100,000 pheromone traps set along the expanding gypsy moth population front for their theoretical model. The pheromone trap data were collected from 1988 to 2004.........

Posted by: Kelly      Permalink         Source


November 15, 2006, 9:35 PM CT

New Way To Manipulate DNA

New Way To Manipulate DNA
Polymers, large molecules comprised of chains of repeating structures, are used in everything from the coatings on walls of ships and pipes to reduce flow drag to gene treatment.

But long polymer chains are subject to breakage, called scission, and a new study by the University of Michigan shows that as it turns out, much of what researchers previously thought about why polymers break when subjected to strong flows, such as waves crashing against a ship's bow, was wrong.

This is important for a few reasons, said Michael Solomon, associate professor in the Department of Chemical Engineering, Macromolecular Science and Engineering Program. Broken polymers don't function as intended, and if researchers don't know what causes them to break, they can't keep them from breaking, nor can they design them to break in specific places.

For the past 40 years, researchers have not understood exactly which forces caused scission, said Solomon, who is the co-author on a paper published last week in the Proceedings of the National Academy of Sciences. The paper, "Universal scaling for polymer chain scission in turbulence," defines which flow forces and at what levels those forces cause polymers to break in turbulence.

"This paper understands how they are breaking in a new way that resolves some issues that have been present for 40 years," Solomon said.........

Posted by: Janet      Permalink         Source

   

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