September 1, 2010, 7:11 AM CT

Free as a bird?

It may seem like birds have the freedom to fly wherever they like, but scientists at the University of Missouri have shown that what's on the ground has a great effect on where a bird flies. This information could be used by foresters and urban planners to improve bird habitats that would help maintain strong bird populations.

"Movement of individuals influences nearly every aspect of biology, from the existence of a single population to interactions within and among species," said Dylan Kesler, assistant professor in fisheries and wildlife at the University of Missouri's School of Natural Resources. "Movement determines where individual birds procreate. How they spread across the landscape affects who meets whom, which in turn dictates how genes are spread".

Kesler has observed that non-migrating resident birds tend to travel over forest "corridors," which are areas protected by trees and used by wildlife to travel. Birds choose to travel over forests because they can make an easier escape from predators as well as find food. Man-made features such as roads, as well as gaps forests from agriculture or rivers, can restrict birds to certain areas. When forests are removed, bird populations become isolated and disconnected, which can lead to inbreeding and weaker, more disease-prone birds......... Posted by: Kelly      Read more         Source

September 1, 2010, 7:08 AM CT

Effects of Sound on Marine Life

A combination of the biology of marine mammals, mechanical vibrations and acoustics has led to a breakthrough discovery allowing researchers to better understand the potential harmful effects of sound on marine mammals such as whales and dolphins.

An international team of scientists from San Diego State University, UC San Diego, and the Kolmården Zoo in Sweden has developed an approach that integrates advanced computing, X-ray Computerized axial tomography scanners, and modern computational methods that give a 3D simulated look inside the head of a Cuvier's beaked whale.

"Our numerical analysis software can be used to conduct basic research into the mechanism of sound production and hearing in these whales, simulate exposure at sound pressure levels that would be impossible on live animals, or assess various mitigation strategies," said Petr Krysl, a UC San Diego structural engineering professor who developed the computational methods for this research. "We think that our research can enable us to understand, and eventually reduce, the potential negative effects of high intensity sound on marine organisms."

The results of this research were recently published in a PLoS ONE article entitled, "A New Acoustic Portal into the Odontocete Ear and Vibrational Analysis of the Tympanoperiotic Complex" by Krysl, Ted W. Cranford, an adjunct professor of research in biology at San Diego State University; and Mats Amundin, a researcher at Sweden's Kolmården Zoo. Sponsors of the research include the office of the Chief of Naval Operations (CNO), Environmental Readiness Division......... Posted by: Kelly      Read more         Source

August 27, 2010, 7:28 AM CT

Complex interactions keep pests under control

Proponents of organic farming often speak of nature's balance in ways that sound almost spiritual, prompting criticism that their views are unscientific and naïve. At the other end of the spectrum are those who see farms as battlefields where insect pests and plant diseases must be vanquished with the magic bullets of modern agriculture: pesticides, fungicides and the like.

Which view is more accurate? A 10-year study of an organic coffee farm in Mexico suggests that, far from being romanticized hooey, the "balance and harmony" view is on the mark. Ecologists John Vandermeer and Ivette Perfecto of the University of Michigan and Stacy Philpott of the University of Toledo have uncovered a web of intricate interactions that buffers the farm against extreme outbreaks of pests and diseases, making magic bullets unnecessary. Their research is described in the July/recent issue of the journal BioScience.

The major players in the system-several ant species, a handful of coffee pests, and the predators, parasites and diseases that affect the pests-not only interact directly, but some species also exert subtle, indirect effects on others, effects that might have gone unnoticed if the system had not been studied in detail.

A key species in the complex web is the tree-nesting Azteca ant (Azteca instabilis). The ants aren't particular about the kind of tree they live in, but for some reason their nests are found in only about 3 percent of shade trees on the farm, and ant-inhabited trees aren't randomly distributed-they're found in clumps......... Posted by: Erica      Read more         Source

August 26, 2010, 11:16 PM CT

Ants use multiple antibiotics as weed killers

Research led by Dr Matt Hutchings and published recently in the journal BMC Biology shows that ants use the antibiotics to inhibit the growth of unwanted fungi and bacteria in their fungus cultures which they use to feed their larvae and queen.

These antibiotics are produced by actinomycete bacteria that live on the ants in a mutual symbiosis.

Eventhough these ants have been studied for more than 100 years this is the first demonstration that a single ant colony uses multiple antibiotics and is reminiscent of the use of multidrug treatment to treat infections in humans.

The work, which was funded by the UK Medical Research Council, has also identified a new antibiotic that could be used to treat fungal infections.

Fungiculture in the insect world is practiced by ants, termites, beetles and gall midges.

Dr Hutchings' research investigates the Acromyrmex octospinosus leaf cutter ant, endemic in South and Central America and the southern US. These ants form the largest and most complex animal societies on earth with colonies of up to several million individuals. The garden worker ants researched were collected from three colonies in Trinidad and Tobago.

Dr Hutchings said: "This was really a fun project which started with a PhD student, Joerg Barke, streaking leaf-cutting ants onto agar plates to isolate antibiotic producing bacteria. Joerg, with his colleagues Ryan Seipke and Sabine Gruschow, really pushed this project forwards and made these major discoveries. They really deserve most of the credit for this work"......... Posted by: Kelly      Read more         Source

August 26, 2010, 11:06 PM CT

Genome Comparison of Ants

By comparing two species of ants, Shelley Berger, PhD, the Daniel S. Och University Professor at the University of Pennsylvania, and his colleagues Danny Reinberg, PhD, New York University, and Juergen Liebig, PhD, Arizona State University, have established an important new avenue of research for epigenetics -- the study of how the expression or suppression of particular genes affects an organism's characteristics, development, and even behavior.

Ants, the new model system used in this study, organize themselves into caste-based societies in which most of the individuals are sterile females, limited to highly specialized roles such as workers and soldiers. Only one queen and the relatively small contingent of male ants are fertile and able to reproduce. Yet despite such extreme differences in behavior and physical form, all females within the colony appear to be genetically identical.

Berger, who directs Penn's Epigenetics program, and his colleagues think that epigenetic mechanisms - chemical modifications to DNA and its supporting proteins that affect gene expression - appears to be critical in establishing such broad variations in behavior and morphology that arise in individuals, despite having the same genome.

As per a research findings published in Science this week, Berger, her Penn colleagues, and a diverse international team of collaborators including ant biologists, geneticists, and biochemists from Arizona State, NYU, Howard Hughes Medical Institute, and the Chinese Academy of Sciences, showed how differences in gene expression between two ant species, the Florida carpenter ant (Camponotus floridanus) and Jerdon's jumping ant (Harpegnathos saltator), correlate with separate castes in each......... Posted by: Kelly      Read more         Source

August 26, 2010, 7:22 AM CT

Move closer to making any crop drought-tolerant

Drought-tolerant crops have moved closer to becoming reality.

A collaborative team of researchers has made a significant advance on the discovery last year by the University of California, Riverside's Sean Cutler of pyrabactin, a synthetic chemical that mimics a naturally produced stress hormone in plants to help them cope with drought conditions.

Led by scientists at The Medical College of Wisconsin, the researchers report in Nature Structural & Molecular Biology (online) on Aug. 22 that by understanding how pyrabactin works, other more effective chemicals for bringing drought-resistance to plants can be developed more readily.

Abscisic acid versus pyrabactin

Plants naturally produced a stress hormone, abscisic acid (ABA), in modest amounts to help them survive drought by inhibiting growth. ABA has already been commercialized for agricultural use. But it has at least two disadvantages: it is light-sensitive and costly to make.

Pyrabactin, conversely, is relatively inexpensive, easy to make, and not sensitive to light. But its drawback is that, unlike ABA, it does not turn on all the "receptors" in the plant that need to be activated for drought-tolerance to fully take hold.

Lock and key

A receptor is a protein molecule in a cell to which mobile signaling molecules such as ABA or pyrabactin, each of which turns on stress-signaling pathways in plants may attach. Commonly at the top of a signaling pathway, the receptor functions like a boss relaying orders to the team below that then proceeds to execute particular decisions in the cell......... Posted by: Erica      Read more         Source

August 25, 2010, 7:08 AM CT

Make Way for Ducklings

Parent birds know best when it comes to taking care of their babies. But, when food gets scarce and they are forced to fly longer distances to grab a bite, "egg sitting" time drops off. What impact does this have on their brood?

"I guess everybody, from a human health perspective, knows that what a mother does during pregnancy can have all sorts of effects on her babies," says Bill Hopkins, an associate professor in the Department of Fisheries and Wildlife Sciences at Virginia Tech. He is holding a duckling in his hand. It's one of a number of he and his team are studying. "We study how these little guys can be affected by the things that mom does".

A member of his research team, Sarah DuRant, examines an egg. "If you look really closely," she says, "you can see the embryo moving".

With the support of the National Science Foundation (NSF), ecologists Hopkins and DuRant are studying wood ducks to better understand the impact of mom's nesting behavior on her ducklings and their ability to survive.

"How much time a female spends on her nest is going to influence the temperature that the nest is at," notes DuRant. The scientists incubate eggs at different temperatures to simulate warmer and cooler nesting conditions. "What we're interested in are very, very subtle changes in temperature, maybe a degree Celsius at most," adds Hopkins......... Posted by: Kelly      Read more         Source

August 25, 2010, 7:06 AM CT

Glue That Holds Oyster

Oyster reefs are on the decline, with over-harvesting and pollution reducing some stocks as much as 98 percent over the last two centuries.

With a growing awareness of oysters' critical roles filtering water, preventing erosion, guarding coasts from storm damage, and providing habitat for other organisms, scientists have been investigating how oyster reefs form in order to better understand the organisms and offer potential guidance to oyster re-introduction projects.

At the same time, scientists have been studying marine animals' various adhesives, uncovering fundamental properties that could yield new innovations from replacements for medical sutures to surface coatings that keep waterborne craft from picking up marine hitchhikers.

Now, scientists from Purdue University and the University of South Carolina have shown that oysters produce a unique adhesive material for affixing themselves to each other, a cement that differs from the glues used by other marine organisms.

The scientists are presenting their findings at the 2010 Annual Meeting of the American Chemical Society in Boston, Mass., on Aug. 24, and will publish their results in the Sept. 15, 2010, issue of the Journal of the American Chemical Society. (The article is available online now.)......... Posted by: Kelly      Read more         Source

August 25, 2010, 7:01 AM CT

Evolutionary response to climate change

Researchers at the University of Oregon have determined the fine-scale genetic structure of the first animal to show an evolutionary response to rapid climate change.

They used a high-throughput sequencing technique called Restriction-site Associated DNA (RAD) tagging to make the discovery.

Their results, which focus on the pitcher plant mosquito, Wyeomyia smithii, are published this week in the journal Proceedings of the National Academy of Sciences (PNAS).

RAD tagging is an effective and straightforward way of barcoding sections of genomic material, much as grocery items are coded at the local supermarket, say the scientists.

"This project demonstrates the power of genomics technologies, which can provide new knowledge about the vast array of Earth's species," says Sam Scheiner, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research.

"Eventhough this small mosquito has become the poster child for genetic response to climate change," says William Bradshaw, one of the paper's co-authors, "its evolution during post-glacial invasion of North America has been a question."

Using the RAD-Tag approach, the researchers have demonstrated that post-glacial populations of Wyeomyia smithii originated from a southern Appalachian Mountain refugium after recession of the Laurentide Ice Sheet some 22,000 to 19,000 years ago......... Posted by: Janet      Read more         Source

August 25, 2010, 6:44 AM CT

Light particles to accelerate algae growth

Researchers and engineers seek to meet three goals in the production of biofuels from non-edible sources such as microalgae: efficiency, economical production and ecological sustainability. Syracuse University's Radhakrishna Sureshkumar, professor and chair of biomedical and chemical engineering in the L.C. Smith College of Engineering and Computer Science, and SU chemical engineering Ph.D. student Satvik Wani have uncovered a process that is a promising step toward accomplishing these three goals.

Sureshkumar and Wani have discovered a method to make algae, which can be used in the production of biofuels, grow faster by manipulating light particles through the use of nanobiotechnology. By creating accelerated photosynthesis, algae will grow faster with minimal change in the ecological resources required. This method is highlighted in the August 2010 issue of Nature Magazine.

The SU team has developed a new bioreactor that can enhance algae growth. They accomplished this by utilizing nanoparticles that selectively scatter blue light, promoting algae metabolism. When the optimal combination of light and confined nanoparticle suspension configuration was used, the team was able to achieve growth enhancement of an algae sample of greater than 30 percent as in comparison to a control......... Posted by: Janet      Read more         Source

August 24, 2010, 7:08 AM CT

Understanding root and seedling development

A biosensor utilizing black platinum and carbon nanotubes developed at Purdue University will help give researchers a better understanding of how the plant hormone auxin regulates root growth and seedling establishment.

Marshall Porterfield, an associate professor of agricultural and biological engineering and biomedical engineering, created a new sensor to detect the movement of auxin along a plant's root surface in real time without damaging the plants.

The nanomaterials at the sensor's tip react with auxin and create an electrical signal that can be measured to determine the auxin concentration at a single point. The sensor oscillates, taking concentration readings at different points around a plant root. An algorithm then determines whether auxin is being released or taken in by surrounding cells.

"It is the equilibrium and transport dynamics that are important with auxin," said Porterfield, whose findings were reported in the early online version of The Plant Journal.

A current focus of auxin research is understanding how this hormone regulates root growth in plants growing on sub-optimal soils. Angus Murphy, a Purdue professor of horticulture and the paper's co-author, said that worldwide pressure on land for food and energy crops drives efforts to better understand how plant roots adapt to marginal soils. Auxin is a main hormones involved in that adaptive growth......... Posted by: Erica      Read more         Source

August 10, 2010, 7:19 AM CT

Hitchhiking bacteria can go against the flow

A newly released co-author of studyed by professor Kam Tang of the Virginia Institute of Marine Science reveals that tiny aquatic organisms known as "water fleas" play an important role in carrying hitchhiking bacteria to otherwise inaccessible lake and ocean habitats.

The article, "Bacteria dispersal by hitchhiking on zooplankton," appeared in the June 29 issue of the Proceedings of the National Academy of Sciences. It was co-authored by researchers from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries in Stechlin, Gera number of.

Bacteria and other microorganisms are key components of aquatic ecosystems, nurturing the base of the food web and recycling organic matter into carbon, nitrogen, and other elemental constituents of global biogeochemical cycles. Some, like Vibrio, can cause disease. Vibrio is responsible for cholera and other water- and shellfish-borne illnesses.

Aquatic microbes are also some of the most abundant, widespread, and diverse organisms on Earth. Researchers estimate that a single tablespoon of seawater holds 5 million marine bacteria, and that a liter can hold tens of thousands of microbial species. Aquatic microbes occur from the deep seafloor to polar lakes, and pretty much everywhere in between.

Yet despite their ubiquity throughout aquatic ecosystems, Tang says the manner by which microbes move from one habitat to another has been somewhat of a mystery. That's because for animals of this small size, water has the viscosity of honey, and the boundary between water masses of different temperature and salinity may as well be a brick wall......... Posted by: Janet      Read more         Source

August 10, 2010, 6:37 AM CT

What Happens Between Mica Sheets

View a video of Helen Hansma of the University of California, Santa Barbara.

That age-old question, "where did life on Earth start?" now has a new answer. If the life between the mica sheets hypothesis is correct, life would have originated between sheets of mica that were layered like the pages in a book.

The so-called "life between the sheets" mica hypothesis was developed by Helen Hansma of the University of California, Santa Barbara, with funding from the National Science Foundation (NSF). This hypothesis was originally introduced by Hansma at the 2007 annual meeting of the American Society for Cell Biology, and is now fully described by Hansma in the September 7, 2010 issue of Journal of Theoretical Biology.

As per the "life between the sheets" mica hypothesis, structured compartments that usually form between layers of mica--a common mineral that cleaves into smooth sheets--may have sheltered molecules that were the progenitors to cells. Provided with the right physical and chemical environment in the structured compartments to survive and evolve, the molecules eventually reorganized into cells, while still sheltered between mica sheets.

Mica chunks embedded in rocks could have provided the right physical and chemical environment for pre-life molecules and developing cells because:........ Posted by: Janet      Read more         Source

August 10, 2010, 6:33 AM CT

Fluorescence Shed New Light

A lot has changed about the way researchers study sexual selection and reproduction. Some of it has to do with new tools; some of it has to do with new attitudes. There is a lot more going on than just "sperm meets egg".

"It was simply thought of as "this army of sperm competing," so it functioned as a raffle; the more tickets you bought, the more sperm you transferred, the more likely you were to win out in that competition," explains Scott Pitnick, a professor of biology at Syracuse University. "Females were perceived as these passive vessels in which this competition played out--that females didn't play an active role. That's really not the case."

With help from the National Science Foundation (NSF), Pitnick studies reproduction and sexual selection in fruit flies.

"A sea change came in the mid-'90s in earnest when people started paying attention to the female side of things, and sperm-female interactions, and it turns out that's really where all the action is," he continues. "There has been a real male bias in this field, as in most fields of science. And now, in the sperm competition field, there are as a number of female as male [scientists], and it really has changed the focus considerably and in a very positive way".

For example, modern DNA technology that can confirm paternity opened scientists' eyes to the reality that monogamy is more the exception than the rule in most species......... Posted by: Kelly      Read more         Source

August 8, 2010, 11:45 PM CT

Flower-Dwelling Yeast

A beneficial yeast that tolerates fungicide may offer a "one-two punch" against Fusarium graminearum, the fungal culprit behind Fusarium head blight ("scab").

U.S. Department of Agriculture (USDA) and Ohio State University (OSU) researchers isolated an improved variant of the yeast Cryptococcus flavescens about two years ago, and are evaluating its potential as a biocontrol agent.

In susceptible wheat and barley varieties, scab-afflicted kernels appear shrunken and chalky-white. The fungus can also produce a mycotoxin that can diminish the grain's value or make it less safe to eat.

Spraying fungicide can reduce scab by 50 to 60 percent; however, farmers are mandatory to stop using the chemicals soon after wheat starts to flower. Eventhough this measure keeps fungicide residues to a minimum, it can leave the grain vulnerable to new invasions by the scab fungus, notes David Schisler, a plant pathologist with USDA's Agricultural Research Service (ARS). He works at the ARS Crop Bioprotection Research Unit in Peoria, Ill. ARS is USDA's chief intramural scientific research agency.

Since 1998, he has teamed with OSU professor Mike Boehm and others to exploit the ability of some microorganisms to outcompete F. graminearum for space and nutrients in wheat's flowers and seed heads......... Posted by: Erica      Read more         Source

August 8, 2010, 11:31 PM CT

As crops wither in Russia's severe drought

As the fate of Europe's largest collection of fruit and berries hangs in the balance of a Russian court decision, the Global Crop Diversity Trust issued an urgent appeal for the Russian government to embrace its heroic tradition as protector of the world's crop diversity and halt the planned destruction of an incredibly valuable crop collection near St. Petersburg. Pavlovsk Experiment Station is the largest European field genebank for fruits and berries, and is part of the N.I. Vavilov Research Institute of Plant Industry, where Russian researchers famously starved to death rather than eat the seeds under their protection during the 900-day siege of Leningrad during World War II.

At issue is an effort by residential real estate developers to build houses on land occupied by Pavlovsk Station. The take-over would involve bulldozing Pavlovsk's field collections amassed over the last centurycollections that contain thousands of varieties of apples, strawberries, cherries, raspberries, currants and other crops90 percent of which are not found anywhere else in the world.

"It is a bitter irony that the single most deliberately destructive act against crop diversity, at least in my lifetime, could be about to happen in Russia of all placesthe country that invented the modern seed bank," said Cary Fowler of the Global Crop Diversity Trust, which aims to ensure the conservation and availability of crop diversity for food security worldwide and supports the operations of the Svalbard Global Seed Vault in the Arctic Circle......... Posted by: Erica      Read more         Source

July 23, 2010, 6:50 AM CT

Ancient "stress hormone" in pre-historic fish

A University of British Columbia zoologist has discovered a new corticosteroid hormone in the sea lamprey, an eel-like fish and one of the earliest vertebrates dating back 500 million years. These findings have shed light on the evolution of steroid hormones and may help conservation and management efforts for lampreys.

"This new discovery has significant scientific implications and application for lamprey conservation," says principal investigator and main author David Close, an assistant professor in the UBC Department of Zoology and director of the Aboriginal Fisheries Research Unit at UBC's Fisheries Centre.

Close and his colleagues at Michigan State University identified a corticosteroid hormone - called 11-deoxycortisol - in the sea lamprey that plays dual roles in balancing ions and regulating stresses, similar to aldosterone and cortisol in humans. The findings are published online this week in the Proceedings of National Academy of Sciences Early Edition.

Native to the Pacific Coast of North America and Asia, Pacific lampreys are an important ceremonial and subsistence food for Aboriginal peoples in the Columbia River basin. They are born in freshwater, swim out to the ocean as adults and return to freshwater to reproduce in similar habitats to Pacific salmon and trout. Adult lampreys can grow to approximately 75 cm long and use their sucker-like mouth to attach to other fish while in the ocean......... Posted by: Kelly      Read more         Source

July 16, 2010, 7:14 AM CT

How Cranberry Juice Fights Bacteria

Revealing the science behind the homespun advice, a team of scientists at Worcester Polytechnic Institute (WPI) has identified and measured the molecular forces that enable cranberry juice to fight off urinary tract infections in people.

The data is published in the paper "Direct adhesion force measurements between E. coli and human uroepithelial cells in cranberry juice cocktail," which was published on-line, ahead of print, by the journal Molecular Nutrition and Food Research. The research illuminates the basic mechanics of E. coli infections, which has implications for developing new antibiotic drugs and infection-resistant materials for invasive medical devices.

The research team led by Terri Camesano, professor of chemical engineering at WPI, focuses on the virulent form of E. coli bacteria that is the primary cause of most urinary tract infections. This strain of E. coli is covered with small hair-like projections known as fimbriae which act like hooks and latch onto cells that line the urinary tract. When enough of the virulent E. coli adhere to cells in this way, they cause an infection. Prior work by Camesano has shown that exposure to cranberry juice causes the fimbriae on E. coli to curl up, reducing their ability to attach to urinary tract cells. In the newly released study, Camesano's team presents the first specific measurements of the mechanical forces involved in the attachment of the virulent E. coli to human urinary tract cells. The study also documents how the force of attachment is reduced in the presence of cranberry juice cocktail. "This is not a clinical study-it's a mechanical study that shows us the direct forces that can lead to infection," Camesano said......... Posted by: Erica      Read more         Source

July 14, 2010, 7:40 AM CT

Rapidly-disappearing ancient plant cycads

Cycads, "living fossil" descendents of the first plants that colonized land and reproduced with seeds, are rapidly going extinct because of invasive pests and habitat loss, particularly those species endemic to islands. But new research on Cycas micronesica published recently as the cover article in Molecular Ecology calls into question the characterization of these plants as relicts (leftovers of formerly abundant organisms), and gives a glimpse into how the remaining plantsthose that survived the loss of more than 90% of their populationcan be conserved and managed. By sampling what is left of C. micronesica on Guam, researchers, including some from the American Museum of Natural History, found moderate genetic variation within local populations and different levels of gene flow between populations.

"Cycas micronesica is one of the most ecologically important plants on Guam and nearby islands, and it is now rapidly disappearing," says Anglica Cibrin-Jaramillo, a researcher at the American Museum of Natural History and at The New York Botanical Garden. "But with new genomic tools we developed microsatellite markers to quickly assess individual plants. This technique is ideal for species that need quick answers for conservation reasons." Microsatellite markers are short genetic sequences typically used to determine how individuals are correlation to each other (kinship) and other population studies......... Posted by: Erica      Read more         Source

July 13, 2010, 7:17 AM CT

Breaking biomass better

One of the challenges in making cellulosic biofuels commercially viable is to cost-effectively deconstruct plant material to liberate fermentable energy-rich sugars. The U.S. Department of Energy (DOE) is funding several projects focused on identifying enzymes in organisms that optimally degrade cellulosic feedstocks. One such source are fungi, which break down dead wood and leaf litter in forests; in fact, some pest management companies consider wood rot more destructive for homes than termites.

The DOE Joint Genome Institute (JGI) previously sequenced and published the genomes of two wood-decaying fungi. Now a team of scientists led by researchers from the DOE JGI and the University of Utrecht announce the analysis of a third such genome as per a research findings published online July 11 in Nature Biotechnology (http://bit.ly/cjkaxO). All told, DOE JGI has sequenced and annotated 40 fungal genomes, and 40 more are currently in the works.

"When we go into a forest we don't see layers of dead branches because wood decay fungi take care of them," said Igor Grigoriev, head of the DOE JGI's Fungal Genomics Program and a senior author on the study. "So when we think about bioenergy and degrading biomass and converting that into biofuel, we would like to learn the most efficient ways of doing that from fungi, which have invented a number of ways of doing that in nature. Schizophyllum commune is the second white rot fungus and third wood degrader we've sequenced. The DOE JGI sequenced the first white rot fungal genome Phanerochaete chrysosporium in 2004. Then last year we sequenced the first brown rot fungal genome Postia placenta." Postia was found to utilize a unique arsenal of small oxidizing agents that blast through plant cell walls to decompose cellulose into simple sugars......... Posted by: Erica      Read more         Source

July 12, 2010, 7:17 AM CT

New virus may pose risk to wild salmon

Farmed fish are an increasingly important food source, with a global harvest now at 110 million tons and growing at more than 8 percent a year. But epidemics of infectious disease threaten this vital industry, including one of its most popular products: farmed Atlantic salmon. Perhaps even more worrisome: these infections can spread to wild fish coming in close proximity to marine pens and fish escaping from them.

Heart and skeletal muscle inflammation (HSMI), an often fatal disease, was first detected in salmon on a farm in Norway in 1999, and has now been reported in 417 fish farms in Norway as well as in the United Kingdom. The disease destroys heart and muscle tissue and kills up to 20 percent of infected fish. Eventhough studies have indicated an infectious basis, recent efforts to identify the pathogen causing the disease have been unsuccessful. Now, using cutting-edge molecular techniques, an international team led by W. Ian Lipkin, MD, the John Snow Professor of Epidemiology and director of the Center for Infection and Immunity at Columbia University's Mailman School of Public Health, has found evidence that the disease appears to be caused by a previously unknown virus. The newly identified virus is related but distinct from previously known reoviruses, which are double-stranded RNA viruses that infect a wide range of vertebrates......... Posted by: Kelly      Read more         Source

July 12, 2010, 7:10 AM CT

Mexican salamander and mysteries of stem cells

Dr Andrew Johnson is speaking today (12 July) at the UK National Stem Cell Network annual conference. He and his team from the University of Nottingham have been using a Mexican aquatic salamander called an axolotl to study the evolution and genetics of stem cells - research that supports the development of regenerative medicine to treat the consequences of disease and injury using stem cell therapies. This team has observed that there are extraordinary similarities in the development of axolotls and mammals that provide unique opportunities to study the properties of embryonic stem cells and germ cells. These findings are underpinned by a novel theory of evolution that unifies the diversity of mechanisms in animal developmental into a single conceptual framework.

Dr Johnson said "We've produced evidence that pluripotency the ability of an embryonic stem cell to become absolutely any kind of cell is actually very ancient in evolutionary terms. Even though received wisdom is that it evolved with mammals, our research suggests that it was there all along, just not in a number of of the species that people use in the lab. In fact, pluripotent cells probably exist in the embryos of the simple animals from which amphibians evolved.

"Axolotls, unlike a number of of the frogs, fish, flies and worms that are used in the lab, have pluripotent cells in their embryos that are the equivalent to those found in embryos from mammals, in that they can produce germ cells, in addition to somatic cells, a property known as ground-state pluripotency. And from a practical perspective, axolotl embryos will provide a very useful tool for understanding how to manipulate embryonic stem cells for modern regenerative medicine"......... Posted by: Kelly      Read more         Source

July 9, 2010, 7:26 AM CT

Refuting conventional thinking on evolution

Long before TV's campy Fantasy Island, the isolation of island communities has touched an exotic and magical core in us. Darwin's fascination with the Galapagos island chain and the evolution of its plant and animal life is just one example.

Think of the extensive lore surrounding island-bred creatures like Komodo dragons, dwarf elephants, and Hobbit-sized humans. Conventional wisdom has it that they - and a horde of monster-sized insects - are all products of island evolution.

But are they?

Dr. Shai Meiri of Tel Aviv University's Department of Zoology says "yes," they are a product of evolution, but nothing more than one would expect to see by "chance," citing research that shows there's nothing extraordinary about evolutionary processes on islands. He and colleagues have conducted many scientific studies comparing evolutionary patterns of island and mainland ecosystems, and the results refute the idea that islands operate under different, "magical" rules.

Man bites evolutionary dog

"My findings are a bit controversial for some evolutionary biologists," says Dr. Meiri, the author of several papers and essays on island evolution. His research is based on statistical models he developed.

"There is a tendency to think that big animals become very small on islands, and small animals become very big, due to limited resources or lack of competition. I've shown that this is just not true, at least not as a general rule. Evolution operates on islands no differently than anywhere else"......... Posted by: Janet      Read more         Source

July 9, 2010, 6:50 AM CT

Ferns and fog on the forest floor

As the mercury rises outdoors, it's a fitting time to consider the effects of summertime droughts and global warming on ecosystems. Complex interactions among temperature, water cycling, and plant communities create a tangled web of questions that need to be answered as we face a rapidly changing climate.

Drs. Emily Limm and Todd Dawson (University of California, Berkeley) recently tackled one aspect of the challenging question of how climate change can impact plant communities that obtain water from fog. Their results are reported in the recent issue of the American Journal of Botany

Fog is an important source of water to ecosystems around the world, because fog allows plants to stay hydrated even during times without rain. Fog may condense and drip to the soil, where it can be taken up by roots. Alternatively, some plants are able to absorb the water from fog through their leaves, allowing these plants to immediately benefit from the atmospheric moisture that may never reach the forest floor. The fern Polystichum munitum covers the forest floors of the redwood forests in northern California. Limm and Dawson examined variation in the ability of the leaves of P. munitum to absorb the water from fog.

The scientists observed that the quantity of water the plants absorbed varied in the different regions of the redwood forest. "Today, summertime drought conditions are greater in the southern end of the redwood forest ecosystem of Northern California, and this reduces P. munitum abundance and plant size. These smaller ferns in the south are less able to capture fog water that drips to the forest floor during the summer, and they may therefore suffer more drought stress than ferns in the northern end of the redwood forest ecosystem," Limm stated......... Posted by: Erica      Read more         Source

July 8, 2010, 6:53 AM CT

What plant genes tell us

Anyone who has seen teosinte, the wild grass from which maize (corn) evolved, might be forgiven for assuming a number of genetic changes underlie the transformation of one plant to the other.

However, a method for exploring the genetics of domestication called Quantitative Trait Locus (QTL) mapping has revealed that only modest modifications are needed to convert a wild plant to a crop plant. Some major transitions in phenotype can even be achieved by a single genetic change.

The few artificial experiments in domestication that have been conducted have also shown that it is possible to achieve domesticate-like plants in fewer than 20 generations.

None of this pleases archaeobotanists, who try to piece together the history of plant domestication from scraps of ancient plant remains.

Their data are sparse and unimpressive - a 10,000-year-old squash seed found in a cave in Oaxaca, Mexico, or four 12,000-year-old grains of rice recovered from a rock shelter in Hunan Province in China - but they have their own irrefutable reality.

"There's been an argument in the recent archeological literature that genetics gives a false picture of domestication as a rapid, geographically localized process," comments Kenneth M. Olsen, PhD, assistant professor of biology in Arts & Sciences at Washington University in St. Louis. "They argue instead that domestication likely involved much trial and error in a number of different geographic regions over a long period of time"......... Posted by: Erica      Read more         Source

July 8, 2010, 6:47 AM CT

Crop development won't satisfy future demand

Eventhough global grain production must double by 2050 to address rising population and demand, new data from the University of Illinois suggests crop yields will suffer unless new approaches to adapt crop plants to climate change are adopted. Improved agronomic traits responsible for the remarkable increases in yield accomplished during the past 50 years have reached their ceiling for some of the world's most important crops.

"Global change is happening so quickly that its impact on agriculture is taking the world by surprise," said Don Ort, U of I professor of crop sciences and USDA/ARS scientist. "Until recently, we haven't understood the urgency of addressing global change in agriculture".

The need for new technologies to conduct global change research on crops in an open-field environment is holding the commercial sector back from studying issues such as maximizing the elevated carbon dioxide advantage or studying the effects of ozone pollution on crops.

However, U of I's Free Air Concentration Enrichment (FACE) research facility, SoyFACE, is allowing scientists to conduct novel studies using this technology capable of creating environments of the future in an open-field setting.

"If you want to study how global change affects crop production, you need to get out of the greenhouse," Ort said. "At SoyFACE, we can grow and study crops in an open-field environment where carbon dioxide and ozone levels can be raised to mimic future atmospheric conditions without disturbing other interactions"......... Posted by: Erica      Read more         Source

July 7, 2010, 7:06 AM CT

Deworming lambs

Deworming lambs can be minimized with rotational grazing and checking the animals' eye color, as per an Agricultural Research Service (ARS) study.

Animal scientist Joan Burke at the ARS Dale Bumpers Small Farms Research Center in Booneville, Ark., and his colleagues made this finding as part of a continuing collaboration with scientists, veterinarians, and extension agents from the Southern Consortium for Small Ruminant Parasite Control.

The consortium was formed in response to the threats posed by worms resistant to parasiticides. Unnecessary de-worming speeds development of resistant worms. Reducing the use of conventional parasiticides fits well into organic and grass-fed management systems and meets consumer preferences of minimizing chemical residues in meat.

The blood-sucking worm, Haemonchus contortus, can cause severe anemia in animals. It is called the barber pole worm for the spiraling of its white, egg-filled ovaries around blood-filled intestines. Worldwide, they cost farmers and ranchers millions of dollars in losses. Animals shed worm eggs with their manure, and the larvae that hatch can be eaten by other livestock.

Burke and his colleagues observed that gel capsules filled with copper oxide wire particles eliminated the need for conventional dewormers in all but one case. And lambs that also rotated pastures needed fewer dewormings with the copper oxide pills......... Posted by: Kelly      Read more         Source

July 7, 2010, 6:59 AM CT

Lone whales shout to overcome noise

noise increases; and just like humans, at a certain point, it appears to become too costly to continue to shout, as per marine and acoustic scientists.

"The impacts of increases in ocean noise from human activities are a concern for the conservation of marine animals like right whales," said Susan Parks, assistant professor of acoustics and research associate, Applied Research Laboratory, Penn State. "The ability to change vocalizations to compensate for environmental noise is critical for successful communication in an increasingly noisy ocean".

Right whales are large baleen whales that often approach close to shore. They may have been given the name because they were the right whales to hunt as they are rich in blubber, slow swimming and remain afloat after death. Consequently, whalers nearly hunted these whales to extinction. Currently right whales are monitored to determine the health and size of the population. The northern and southern right whales are on the endangered species list.

"Right whale upcalls are used extensively for passive acoustic monitoring in conservation efforts to protect this endangered species," said Parks.

Whales produce upcalls, sometimes called contact calls, when they are alone or in the process of joining with other whales. An upcall begins low and rises in pitch. It is the most frequent call produced by right whales......... Posted by: Kelly      Read more         Source

July 6, 2010, 7:16 AM CT

Salmon in hot water

Rearing juvenile salmon at the relatively high temperature of 16C causes skeletal deformities in the fish. Scientists writing in the open access journal BMC Physiology investigated both the magnitude and mechanisms of this effect, which occurs when salmon farmers use warmed water to increase fish growth rates.

Harald Takle worked with a team of scientists from NOFIMA (the Norwegian Institute of Food, Fisheries and Aquaculture Research), Norway, to carry out the studies. He said, "The data presented here indicate that both production of bone and cartilage were disrupted when promoting fast growth using elevated temperature. It is very likely that higher temperatures result in the increased rate of deformities observed in the 16C group".

The scientists reared 400 fish in 10C water and another 400 at 16C. The fish in the 16C water grew faster, but 28% were found to show some signs of skeletal deformity, in comparison to 8% of the fish reared in the cooler tank. Takle said, "Our results strongly indicate that temperature induced fast growth is severely affecting gene transcription in osteoblasts and chondrocyte bone cells, leading to a change in the tissue structure and composition".

In a second related study, fish with vertebral deformities were studied in detail. Takle said, "The deformity process involves molecular regulation and cellular changes similar to those found in mammalian intervertebral disc degeneration"......... Posted by: Kelly      Read more         Source

July 6, 2010, 7:13 AM CT

Digital embryo gains wings

The researchers at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Gera number of, who 'fathered' the Digital Embryo have now given it wings, creating the Fly Digital Embryo. In work published recently in Nature Methods, they were able to capture fruit fly development on film, and were the first to clearly record how a zebrafish's eyes and midbrain are formed. The improved technique will also help to shed light on processes and organisms, which have so far been under-studied because they could not be followed under a microscope.

"Non-transparent samples like the fruit fly embryo scatter light, so the microscope picks up a mixture of in-focus and out-of-focus signal good and bad information, if you like," says Ernst Stelzer, whose group carried out the project at EMBL. "Our new technique enables us to discriminate between that good and bad information, so it allows us to record organisms which have so far been poorly studied, because of their unfortunate optical properties".

Philipp Keller, who co-led and conducted the work, and Ernst Stelzer overcame the difficulties caused by thick, opaque samples, by shining patterns of light on them, instead of the usual continuous light sheet. This generates an image with alternating light and dark stripes, unless the light bounces off the sample and changes direction, in which case this stripy pattern will be blurred. By taking multiple images of different phases of the light pattern, and combining them, a computer can filter out the effects of scattered light and generate an accurate image of the sample, thus enabling researchers to record images that were previously unobtainable......... Posted by: Kelly      Read more         Source

July 1, 2010, 7:04 AM CT

Improving Freezing Tolerance in Wheat

New research by UC Davis wheat geneticist Jorge Dubcovsky and colleagues could lead to new strategies for improving freezing tolerance in wheat, which provides more than one-fifth of the calories consumed by people around the world.

The new findings, published June 22 in the Online First issue of the journal Plant Physiology, shed light on the correlation between flowering and freezing tolerance in wheat.

In winter wheat and barley varieties, long exposures to non-freezing cold temperatures accelerate flowering time in a process known as vernalization. These exposures also prepare the wheat to better tolerate freezing, a process known as cold acclimation.

In their newly released study, Dubcovsky and colleagues at UC Davis, The Ohio State University and in Hungary, demonstrated that when the main vernalization gene, VRN1, is expressed in the leaves, it initiates a process that leads to decreased expression of the freezing tolerance genes. (In genetics, "expression" refers to the process by which information carried by the gene is used to create a protein.).

"This system enables wheat and other temperate grasses to respond differently to cool temperatures in the fall than they would to cool temperatures in the spring," said Dubcovsky, a professor in UC Davis' Department of Plant Sciences......... Posted by: Erica      Read more         Source

June 30, 2010, 6:50 AM CT

Deaths in the family cause bacteria to flee

The deaths of nearby relatives has a curious effect on the bacterium Caulobacter crescentus -- surviving cells lose their stickiness.

Indiana University Bloomington biologists report in an upcoming issue of Molecular Microbiology that exposure to the extracellular DNA (eDNA) released by dying neighbors stops the sticky holdfasts of living Caulobacter from adhering to surfaces, preventing cells from joining bacterial biofilms. Less sticky cells are more likely to escape established colonies, out to where conditions appears to be better.

Harmless Caulobacter live in nutrient-poor, aqueous environments like lakes, rivers, and even tap water. Like a number of other bacteria, Caulobacter form biofilms, aggregations of cells held in place by a sticky matrix produced by the bacteria themselves. Bacteria in biofilms are more resistant to predators and to antibiotics, and are less affected by environmental stress. However, if environmental conditions worsen, it becomes advantageous for the bacteria to get away.

That presents a special problem for Caulobacter In 2006, microbiologist Yves Brun, the project's principal investigator, and Brown University colleagues learned that the sugar-protein glue the bacteria use to attach themselves to the biofilm matrix is the strongest adhesive known in nature. Once a cell joins the collective, it is stuck there......... Posted by: Janet      Read more         Source

June 29, 2010, 7:23 AM CT

Longer shelf life for tomatoes

A Purdue University researcher has found a sort of fountain of youth for tomatoes that extends their shelf life by about a week.

Avtar Handa, a professor of horticulture, observed that adding a yeast gene increases production of a compound that slows aging and delays microbial decay in tomatoes. Handa said the results, reported in the early online version of The Plant Journal, likely would transfer to most fruits.

"We can inhibit the aging of plants and extend the shelf life of fruits by an additional week for tomatoes," Handa said. "This is basic fundamental knowledge that can be applied to other fruits".

The organic compound spermidine is a polyamine and is found in all living cells. Polyamines' functions aren't yet fully understood. Handa and Autar Mattoo, a research plant physiologist with the U.S. Department of Agriculture's Agricultural Research Service and collaborator in the research, had shown earlier that polyamines such as spermidine and spermine enhance nutritional and processing quality of tomato fruits.

"At least a few hundred genes are influenced by polyamines, maybe more," Mattoo said. "We see that spermidine is important in reducing aging. It will be interesting to discover what other roles it can have".

Savithri Nambeesan, who was a graduate student in Handa's laboratory, introduced the yeast spermidine synthase gene, which led to increased production of spermidine in the tomatoes. Fully ripe tomatoes from those plants lasted about eight days longer before showing signs of shriveling compared with non-transgenic plants. Decay and rot symptoms linked to fungi were delayed by about three days......... Posted by: Erica      Read more         Source

June 24, 2010, 11:19 PM CT

Plants demonstrate complex ability to integrate information

A University of Alberta research team has discovered that a plant's strategy to capture nutrients in the soil is the result of integration of different types of information.

U of A ecologist J.C. Cahill says the plant's strategy mirrors the daily risk-versus-reward dilemmas that animals experience in their quest for food.

Biologists established long ago that an animal uses information about both the location of a food supply and potential competitors to determine an optimal foraging strategy. Its subsequent behavioral response is based on whether the food supply is rich enough to accept the risks linked to engaging in competition with other animals.

Cahill found plants also have the ability to integrate information about the location of both food and competitors. As a result, plants demonstrate unique behavioural strategies to capture soil resources.

Prior studies show plants alter the growth of their roots in relation to the placement of food or a competing plant. Cahill and colleagues now show an integration of both location and competition information in plants. "This ability to integrate information is a level of complexity never seen in plants before," said Cahill. "This is something we assumed only happened with animals." .

Using a mini-rhizotron camera, referred to by Cahill's team as a "camera on a stick," the scientists compared the root movement of potted plants in relation to various positions of nutrients and competing plants......... Posted by: Erica      Read more         Source

June 24, 2010, 11:15 PM CT

System that controls sleep

In a novel mathematical model that reproduces sleep patterns for multiple species, an international team of scientists has demonstrated that the neural circuitry that controls the sleep/wake cycle in humans may also control the sleep patterns of 17 different mammalian species. These findings, reported by scientists from Brigham and Women's Hospital (BWH), the University of Sydney, and the Center for Integrated Research and Understanding of Sleep (Camperdown, Australia), suggest that fundamental physiological mechanisms are at work across diverse species, even though sleep patterns vary drastically. This research published June 24th in the open-access journal PLoS Computational Biology.

"These findings show that eventhough mammalian sleep is remarkably diverse in expression, from dolphins who sleep with one brain half at a time to rodents who have a number of short naps, it is very likely universal in origin, which suggests that this simple system is both highly flexible and evolutionarily conserved," said Andrew Phillips, main author of the paper and researcher in the Division of Sleep Medicine at BWH.

Over the past decade, scientists have reported findings correlation to the structures in the brain that are critical to sleep regulation, but these findings have been limited to a small number of species. Until now, it was unclear to what extent these physiological mechanisms are universal across all mammals, particularly given such large interspecies differences in sleep patterns......... Posted by: Kelly      Read more         Source

June 24, 2010, 11:11 PM CT

How light receptors get their message across

-For a plant, light is life. It drives everything from photosynthesis to growth and reproduction. Yet the chain of molecular events that enables light signals to control gene activity and ultimately a plant's architecture had remained in the dark. Now a team of scientists from the Salk Institute for Biological Studies and Duke University have identified the courier that gives the signal to revamp the plant's gene expression pattern after photoreceptors have been activated by light.

"Light is probably the most important environmental cue for a plant," says Howard Hughes Medical Institute investigator Joanne Chory, Ph.D., professor and director of the Plant Molecular and Cellular Biology Laboratory and holder of the Howard H. and Maryam R. Newman Chair. "Understanding how light signaling triggers morphological changes in the plant will have a really big impact on every facet of plant biology".

Most animals are able to move away from unfavorable conditions, but plants are sessile and must cope with whatever comes their way. "They have developed an amazing plasticity to deal with varying environmental conditions," says first author Meng Chen, Ph.D., formerly a postdoctoral researcher in the Chory laboratory and now an assistant professor in the Department of Biology at Duke University......... Posted by: Erica      Read more         Source

June 24, 2010, 11:09 PM CT

Genetics in bloom

Some of the molecular machinery that governs flower formation has been uncovered in the daisy-like Gerbera plants. Scientists writing in the open access journal BMC Plant Biology have published a pair of articles detailing how the complex Gerbera inflorescence is formed and how this process differs from other model plants, such as the more simple flowers of Arabidopsis species.

Teemu Teeri, from the University of Helsinki, Finland, worked with a team of scientists to carry out the studies. He said, "Gerbera, a member of the sunflower family, bears compressed inflorescence heads with three different flower types characterized by differences in both sex and floral symmetry. To understand how such a complex inflorescence structure is achieved at the molecular level, we have characterized the array of Gerbera MADS box genes".

The scientists analyzed the expression and evolutionary relationships of six Gerbera genes (GSQUA1-6) that are closely correlation to flower architecture genes in other model species. It seems that this group of genes has expanded in the daisy plant family probably reflecting new functions for these genes in the formation of the complex Gerbera inflorescence. Teeri said, "Our data indicate that none of the GSQUA genes are, by themselves, likely to play a role in defining floral organ identity in the sense of the 'A' function of the floral ABC model. Based on these results, Gerbera can be added to the growing list of plant species that lack the 'A' function comparable to Arabidopsis"......... Posted by: Erica      Read more         Source

June 24, 2010, 10:47 PM CT

Ecological change in the abyss

Even in the dark abyss of the deep ocean animal communities can undergo rapid, widespread and radical changes. Researchers at the National Oceanography Centre are at the forefront of monitoring these changes and understanding the mechanisms responsible. Their latest research is published in a special issue of the journal Deep Sea Research II.

We often think of the deep ocean floor as stable, relatively unvarying environment untroubled by surface climate conditions. But long-term monitoring has shown that animal communities living at great depth on the seafloor can change radically over remarkably short periods, and that these events are ultimately driven by climate.

Such faunal changes are exemplified by the 'Amperima Event' the sudden mass occurrence of the sea cucumber (holothurian) Amperima rosea recorded on the Porcupine Abyssal Plain (PAP) situated off the southwest coast of Ireland in the northeast Atlantic. Communities of animals living on the seabed there at depths of nearly 5000 metres have been monitored from 1989 to the present day.

A major change occurred in the PAP community between 1996 and 1999 involving many animal groups, including sea anemones, segmented worms, sea spiders, sea squirts, brittle stars, and sea cucumbers, all of which increased in abundance......... Posted by: Janet      Read more         Source

June 24, 2010, 10:36 PM CT

Even brooding female birds are sensitive to visual stimulation

In a breeding experiment with Houbara bustards - a North African bird species with a very distinctive courtship behaviour, researchers have concluded that visual stimulation from attractive males of the same species positively affects brooding females, improving offspring growth. Females that observed highly displaying male birds in the experiment were more fertile and had a greater breeding success due to an increased allocation of testosterone into their eggs, leading to an increase in the growth rate in chicks. The results showed that using artificial insemination without appropriate stimulation of breeding females probably has negative impacts on their breeding performance and can therefore even affect the survival of a species, as per Adeline Loyau and Frederic Lacroix in the online edition of Proceedings of the Royal Society B

For the experiment, Loyau of the Helmholtz Center for Environmental Research (UFZ) and the French CNRS station for experimental ecology and her colleague Lacroix (ECWP) confronted 90 brooding Houbara bustard females (Chlamydotis undulata undulata) with various individuals of the same species. In the Emirates Center for Wildlife Propagation (ECWP) in Moroccan Missour, 30 female birds were visually confronted with either highly displaying male birds, poorly displaying male birds, or females. During the experiment the female birds under investigation were artificially inseminated and kept isolated in aviaries five meters apart from birds of the same species in other aviaries. That way the researchers were able to exclude any other factors from playing a role in the experiment other than that of visual stimulation. "To my knowledge our study is the first example in species conservation of a successful manipulation of maternal allocation of resources through sensory stimulation ", explains behavioural biologist Adeline Loyau from the UFZ, "Our results show that it is possible to control maternal allocation of resources independent of the quality of male genes." Male display courtship constitutes an effective signal thereby providing conservationists with a simple and inexpensive means. The results could therefore be very significant for the improvement of captive breeding programs of other threatened bird species......... Posted by: Kelly      Read more         Source

June 24, 2010, 10:27 PM CT

Climate change complicates plant diseases

Human-driven changes in the earth's atmospheric composition are likely to alter plant diseases of the future. Scientists predict carbon dioxide will reach levels double those of the preindustrial era by the year 2050, complicating agriculture's need to produce enough food for a rapidly growing population.

University of Illinois scientists are studying the impact of elevated carbon dioxide, elevated ozone and higher atmospheric temperatures on plant diseases that could challenge crops in these changing conditions.

Darin Eastburn, U of I associate professor of crop sciences, reviewed the effects of elevated carbon dioxide and ozone on three economically important soybean diseases under natural field conditions at the soybean-free air-concentrating enrichment (SoyFACE) facility in Urbana.

The diseases downy mildew, Septoria brown spot, and sudden death syndrome were observed from 2005 to 2007 using visual surveys and digital image analysis. While changes in atmospheric composition altered disease expression, the responses of the three pathosystems varied considerably, Eastburn said.

Elevated carbon dioxide levels are more likely to have a direct effect on plant diseases through changes to the plant hosts rather than the plant pathogens.

"Plants growing in a high carbon dioxide environment tend to grow faster and larger, and they have denser canopies," Eastburn said. "These dense plant canopies favor the development of some diseases because the low light levels and reduced air circulation allow higher relative humidity levels to develop, and this promotes the growth and sporulation of a number of plant pathogens"......... Posted by: Erica      Read more         Source

June 24, 2010, 10:16 PM CT

Plant growth hormones

The two most important growth hormones of plants, so far considered antagonists, also work synergistically. The activities of auxin and cytokinin, key molecules for plant growth and the formation of organs, such as leaves and buds, are in fact more closely interwoven than previously assumed. Researchers from Heidelberg, Tbingen (Gera number of) and Umea (Sweden) made this surprising discovery in a series of complex experiments using thale cress (Arabidopsis thaliana), a biological reference organism. The international team of researchers, led by Jan Lohmann, stem cell biologist at Heidelberg University, have now published their results in the scientific journal "Nature". (Nature, 24. Juni 2010).

All the above-ground parts of a plant leaves, buds, stems and seeds ultimately arise from a small tissue at the shoot tip, which contains totipotent stem cells. Since plant stem cells remain active over the entire life of the organism, plants, unlike animals, are able to grow and develop new organs over a number of decades. On the periphery of the tip, auxin triggers cells to leave the pool of stem cells, differentiate and form organs like leaves and buds. Cytokinin stimulates stem cells to divide and proliferate; it maintains the number of cells and thus the plant's growth potential......... Posted by: Erica      Read more         Source

June 24, 2010, 10:15 PM CT

3D Models of Whole Mouse Organs

Yale University engineers have for the first time created 3D models of whole intact mouse organs, a feat they accomplished using fluorescence microscopy. The team reports its findings in the May/recent issue of the Journal of Biomedical Optics, as per a research findings published online this week.

Combining an imaging technique called multiphoton microscopy with "optical clearing," which uses a solution that renders tissue transparent, the scientists were able to scan mouse organs and create high-resolution images of the brain, small intestine, large intestine, kidney, lung and testicles. They then created 3D models of the complete organs-a feat that, until now, was only possible by slicing the organs into thin sections or destroying them in the process, a disadvantage if more information about the sample is needed after the fact.

With traditional microscopy, scientists are only able to image tissues up to depths on the order of 300 microns, or about three times the thickness of a human hair. In that process, tissue samples are cut into thin slices, stained with dyes to highlight different structures and cell types, individually imaged, then stacked back together to create 3D models. The Yale team, by contrast, was able to avoid slicing or staining the organs by relying on natural fluorescence generated from the tissue itself......... Posted by: Kelly      Read more         Source

June 21, 2010, 7:12 AM CT

Increasing Potato Production

Despite sophisticated nutrient management of potato crops, quality and yield still see wide variability. Eventhough nutrients are already well understood, the influence of other environmental factors remains understudied.

A research team from Michigan State University conducted a study to determine how the chemical and physical properties of soil, along with the light waves the plant absorbs and reflects, affect potato yield and variability. These findings were integrated with known factors to provide a more complete understand of the influences on potato growth.

Sieglinde Snapp and Alexandra Kravchenko from Michigan State University, and Edgar Po from the University of Missouri reported their findings in the May-June 2010 Agronomy Journal, published by the American Society of Agronomy. Measured across a number of different soil chemical and physical properties, they observed that soil structure was a significant variable that contributed to positive potato yield across coarse-textured commercial field sites.

The study demonstrated the need to supplement monitoring of soil chemical properties, which is a common practice, with data on soil structure and spectral profiles. Soil structure improvement requires dedicated management, but stable soil particle size and their stability in water was a sensitive predictor of field-level variability in potato tuber yield......... Posted by: Erica      Read more         Source

June 17, 2010, 11:23 PM CT

Caribbean coral reef protection efforts

Conservation efforts aimed at protecting endangered Caribbean corals appears to be overlooking regions where corals are best equipped to evolve in response to global warming and other climate challenges.

That's the take-home message of a paper published in this week's issue of the journal Science by scientists Ann Budd of the University of Iowa and John Pandolfi of the University of Queensland, Australia.

Budd and Pandolfi focus on understanding the biodiversity of reef-building corals--organisms that are highly diverse and seriously threatened.

Their work focuses on evolutionary processes documented in the fossil record over long time periods, a history that encompasses and shows the effects of global environmental change.

"The research demonstrates that the predominance of evolutionary innovation occurs at the outlying edges of Caribbean coral species ranges, as opposed to the well-connected central part of the Caribbean," said H. Richard Lane, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research along with NSF's Division of Environmental Biology.

The researchers conclude that if coral reef conservation strategies protect only the centers of high species richness, they will miss important sources of evolutionary novelty during periods of global change......... Posted by: Janet      Read more         Source

June 14, 2010, 10:08 PM CT

Sequencing the salmon genome

The economically important, environmentally sensitive Atlantic salmon species is one step closer to having its genome fully sequenced, thanks to an international collaboration involving researchers, funding agencies and industry from Canada, Chile and Norway.

Genome BC partnered with the Chilean Economic Development Agency, InnovaChile, Norwegian Research Council, Norwegian Fishery and Aquaculture Industry Research Fund to form the International Cooperation to Sequence the Atlantic Salmon Genome (the Cooperation).

Together they are well underway on a multi-million dollar, multi-phased project that will produce a genome sequence that identifies and maps all of the genes in the Atlantic salmon genome and can act as a reference/guide sequence for the genomes of other salmonids (e.g. Pacific salmon, rainbow trout and more distantly related fish such as smelt and pike.).

Phase one of the project was awarded to Beckman Coulter Genomics to produce a 4X coverage genome using paired-end, plasmid, fosmid and BAC Sanger sequences. It is expected that this phase will be complete in January, 2011.

The Cooperation is gearing up for phase two which will result in a high definition and well-annotated genome using primarily next generation sequencing technologies. The Cooperation is seeking interested parties (publically or privately funded genome sequencing centres, or public/private partnerships) to undertake phase two......... Posted by: Kelly      Read more         Source

June 9, 2010, 11:25 PM CT

Impact of fishing on remote coral reefs

Coral reefs - kaleidoscopes of pink anemones and silver sharks - are the planet's most colorful ecosystems and among its most endangered, say marine scientists.

As global warming raises ocean temperatures, a number of corals blanch and die, a phenomenon called "coral bleaching." And pumping large amounts of carbon dioxide into the atmosphere could make the ocean more acidic, further decimating corals and the fish that depend on them for food and shelter.

Millions of people inhabit coral reefs around the world, putting additional pressure on reef menageries. Establishing sustainable fisheries, even at remote islands and atolls, could significantly slow the decline of a number of reefs, say marine ecologists.

"We know that fishing can dramatically change the composition of a reef ecosystem," said Fiorenza Micheli, a professor of biology at Stanford University's Hopkins Marine Station. "By confronting overfishing immediately, we may increase the resilience of coral reefs to global warming and other threats".

To gain new insights on the ecology of reef fishing, Micheli and a team of Stanford scientists are taking advantage of an ongoing "natural experiment" at two isolated Pacific atolls - Palmyra and Tabuaeran (or Fanning Island) - located about 1,000 miles south of Hawaii. The project is funded by Stanford's Woods Institute for the Environment......... Posted by: Kelly      Read more         Source

June 9, 2010, 6:49 AM CT

Arsenic hyperaccumulating ferns

Arsenic is toxic to most forms of life, and occurs naturally in soil and ground water in a number of regions of the world. Chronic exposure to arsenic has been associated with lung, bladder and kidney cancer, and thus there are strict limits on allowable levels or arsenic in drinking water. Chemically similar to phosphorus, arsenic forms arsenate (AsO43-), which closely resembles phosphate (PO43-). Arsenate interferes with a number of phosphate-requiring metabolic reactions, including synthesis of adenosine triphosphate (ATP), a ubiquitous and essential source of cellular energy. Thus, exposure to even low levels of arsenic can be extremely toxic.

In well-aerated soils, arsenic exists mainly as arsenate, which is taken up by plant roots using a phosphate transporter protein. Plant tissues rapidly reduce arsenate to arsenite (AsO33-), which is transported to the aerial portions of the plant. In aquatic environments or water-logged soils, arsenic exists primarily as arsenite. Whereas rice grains can accumulate up to 60 µg/g arsenic, the fern Pteris vittata (see figure) can hyperaccumulate arsenic to levels 1000-fold greater than this. A team of scientists led by David Salt and Jo Ann Banks of Purdue University have recently isolated a gene encoding an arsenite transporter protein. This transporter allows these ferns to sequester arsenic in the vacuole, a cellular storage compartment isolated from the cytoplasm by the vacuolar membrane......... Posted by: Erica      Read more         Source

May 15, 2010, 8:49 PM CT

Boosting benefits of broccoli and tomatoes

A University of Illinois study has demonstrated that agronomic practices can greatly increase the cancer-preventive phytochemicals in broccoli and tomatoes.

"We enriched preharvest broccoli with different bioactive components, then assessed the levels of cancer-fighting enzymes in rats that ate powders made from these crops," said Elizabeth Jeffery, a U of I professor of food science and human nutrition.

The highest levels of detoxifying enzymes were found in rats that ate selenium-treated broccoli. The amount of one of the cancer-fighting compounds in broccoli was six times higher in selenium-enriched broccoli than in standard broccoli powder, she said.

Selenium-treated broccoli was also most active in the liver, reaching a level of bioactivity that exceeded the other foods used in the experiment.

"We were intrigued to find that selenium initiated this amount of bioactivity," she said.

Along with garlic and other plants of the allium family, broccoli and other plants of the brassica family are unique in having a methylating enzyme that enables plants to store high concentrations of selenium, she said.

"Our bodies need a certain amount of selenium, but a number of areas of the world, including parts of the United States and vast areas of China, have very little selenium in the soil," she said......... Posted by: Erica      Read more         Source

May 6, 2010, 6:44 AM CT

Mammal Diversity Patterns

Travel from the tropics to the poles, and you'll notice that the diversity of mammals declines with distance from the equator. Move from lowland to mountains, and you'll see diversity increase as the landscape becomes more varied. Ecologists have proposed various explanations for these well-known "biodiversity gradients," invoking ecological, evolutionary and historical processes.

New findings by University of Michigan scientists John A. Finarelli and Catherine Badgley suggest that the elevational patterns of diversity we see today have appeared, disappeared and reappeared over Earth's history and that these patterns arise from interactions between climate change and mountain building.

The results, published online in the journal Proceedings of the Royal Society B, also have implications for conservation efforts in the face of modern-day global warming, said Finarelli, a visiting assistant professor in the Department of Geological Sciences.

In their study, focused on the Miocene Epoch, which began around 23 million years ago and ended about 5 million years ago, Finarelli and Badgley reviewed diversity for more than 400 rodent species from adjacent regions that differed in geologic history and topography. The geologically "active region," which extends from the Front Range of the Rocky Mountains to the Pacific coast, has experienced several episodes of mountain-building and volcanic activity, and as a result has a topographically complex landscape. In contrast, the relatively flat Great Plains, has been more stable geologically......... Posted by: Kelly      Read more         Source