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Livestock are recognized as a significant source of the world's greenhouse gas emissions. To address this issue, scientists in Australia and New Zealand are working to develop a new type of grass designed to reduce the amount of methane produced by cows. When cellulose, the structural component of the primary cell wall of green plants, is digested in the cow gut, methane gas is created as a by-product. It is estimated that one dairy cow can produce between 550-700 liters of methane in a single day. To reduce these emissions, scientists are trying to create more easily digestible grass by suppressing the expression of a specific grass enzyme (O-methyl transferase). The modification should not compromise the structural properties of the grass and may allow it to grow in hotter climates. While some researchers believe that this strategy could lead to reduced methane production in cows, others are skeptical, and some even have suggested that this approach will lead to an increase in the absolute levels of methane released by cows. Field tests are being planned to investigate whether or not this will be an effective approach to combat greenhouse gas emissions of the agricultural industry.

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The first complete draft of the human genome sequence was released in 2003 as part of the Human Genome Project. Now, Evan Eichler and his colleagues at the University of Washington have produced the first high-resolution map revealing the structural variation that exists in the human genome. The team examined the complete DNA sequences of eight individuals: four of African decent, two of Asian descent, and two of Western European descent, and compared these sequences with the "reference sequence" derived from the Human Genome Project. Rather than focusing on differences in specific DNA base pairs that exist among individuals, Eichler's group investigated genetic differences involving larger segments of DNA - structural changes including insertions, duplications and deletions of DNA. Their analyses revealed tremendous variation across the nine genomes, including 1,695 regions where structural differences of greater than approximately 6,000 base pairs were found in one or more of the individual genomes investigated. Learning about these structural differences in the human genome will help scientists understand the role of genetic variation in human health and may lead to the development of new technologies aimed at detecting genetic differences among individuals.

Primary Source: Kidd, J. M. et al. (2008). Mapping and sequencing of structural variation from eight human genomes. Nature, 453: 56-64.

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The world's largest and most ancient freshwater lake is becoming warmer as revealed in an analysis of sixty years of monitoring data. The 25 million-year-old Lake Baikal contains 20 percent of the world's fresh water and is located in Siberia. The lake is home to more than 2,500 species, including the world's only species of freshwater seals. A single family of biologists has measured temperatures and sampled microscopic life at different depths in the lake since 1945. The data show significant warming of the surface temperatures and important changes in the lake's food webs. Ecologists interpret these changes to be the result of global warming, which is affecting even the most remote locations on the planet.

Primary Source: Hampton, S.E. et al. 2008. Sixty years of environmental change in the world's largest freshwater lake - lake Baikal, Siberia. Global Change Biology.

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New genetic sequencing data has grouped Tyrannosaurus rex most closely with modern birds, ostrich and chicken. The analysis was performed on collagen protein extracted from a 68-million-year-old T. rex femur. Collagen sequences from 21 extant (existing) species, such as alligator, elephant and green anole, and also mastodon (Mammut americanum), were included in the study. The investigators used several different mathematical approaches to generate trees of evolutionary relationships among the organisms. Mastodon was grouped consistently with elephant. T. rex clustered most closely with modern birds, instead of with reptiles, such as alligator. These results are consistent with conclusions that have been drawn from the careful examination of skeletal structures. 

Primary Source: Organ, C. et al. (2008). Molecular phylogenetics of mastodon and Tyrannosaurus rex. Science, 320: 499.

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Solar energy is one of the most abundant forms of energy on earth. It can be converted into other forms of energy including heat and electricity. Yet, there are challenges associated with the use of solar power as an energy source: the amount of sunlight that reaches the earth's surface is inconsistent, and solar power has proven difficult to store. As a result, even those who choose to use this renewable energy source often must turn to traditional fossil fuels for their energy needs at night or on cloudy days. The solar power industry has been trying to find new ways to make solar energy a viable alternative energy source for use when the sun is not out, a mission fueled by recent public concern about greenhouse gas emissions. Solar energy typically is made useful in one of three ways: as a heating source for hot water, through photovoltaic cells (which directly convert solar energy into electricity ) or through thermal solar power (which involves heating water to create high temperature steam which, in turn, is used to power a turbine for electricity production). All three processes suffer inefficiencies due to the inconsistent nature of solar energy. The industry is now experimenting with several ways to store solar energy as heat for longer periods before using it to generate electricity. One possible solution: using the sun's energy to heat tens of thousands of gallons of molten salt held in a giant, insulated tower.

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The body of a 37,000-year-old baby woolly mammoth was discovered in the frozen Arctic in 2007. The well-preserved specimen, named Lyuba, recently underwent several computer tomography (CT) scans at The Jikei University School of Medicine in Tokyo. The scans produced three-dimensional images of Lyuba's internal organs, images that provide insight into the anatomy of the woolly mammoth as well as hints about how Lyuba died. As a next step, researchers are interested in analyzing tissue and bone samples from the specimen. Such studies are likely to provide information about the structure of the internal organs, glands, and muscle tissue of the woolly mammoth. In addition, scientists predict that ancient viruses, pollen and spore samples may be found in the preserved tissue and organs of this animal. The potential to decode the woolly mammoth genome also may lie in the samples taken from this prehistoric mammal.

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Amphibians are a group of cold-blooded animals that generally spend time both in water and on land. Like most animals, amphibians such as frogs and salamanders normally have lungs that allow them to inhale air and supply the body with oxygen. Recently, scientists identified a rare exception - a lungless frog named Barbourula kalimantanensis that gets all of its oxygen through its skin. The frog was discovered in a stream on the island of Borneo in Indonesia and researchers speculate that its lunglessness may be an adaptation to the high oxygen content of the cold, fast-moving water of the stream. In addition, "having lungs makes you more likely to be swept away in a fast-flowing stream," points out David Bickford, lead author of the study. Other interesting features of the frog include a low metabolic rate, which means it requires less oxygen, and a flat body type, which increases the surface area of its skin.

Primary source: Bickford, D., Iskandar, D., & Barlian, A. (2008). A lungless frog discovered in Borneo. Current Biology, 18.

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Horses suffer from arthritis and many other chronic leg and hoof ailments. Researchers in Texas used gene therapy to treat laminitis, a serious foot and hoof condition. The well-known racehorse, Barbaro, for example, suffered severe laminitis in the months following his catastrophic leg fracture. In a pilot study to be reported in the Journal of Gene Medicine, veterinary scientists injected a plasmid (a small, nonreplicating fragment of DNA) containing a gene for the production of growth hormone-releasing hormone (GHRH) into the muscles of horses with lameness. Afterwards, electric pulses were delivered through the skin of the horses to "open" pores in the horses' cells to promote uptake of the plasmids. After six months, the experimental horses' lameness improved, as compared to control horses. GHRH promotes the production of hormones that play roles in reducing inflammation.

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Researchers speaking at the 2008 meeting of the Society for General Microbiology announced that "friendly" bacteria isolated from raw milk Feta cheese naturally produce compounds that may protect humans from various food pathogens. These compounds, known as bacteriocins, are toxins produced by bacteria that inhibit the growth of other bacteria. The strains of bacteriocin producing bacteria found in raw milk Feta cheese appear capable of surviving and growing in conditions that often are hazardous to other bacteria, including the low temperature of the refrigerator and the salty conditions of much of the cheese. Scientists hope to use the bacteriocin producing bacteria to fight disease-causing bacteria, including Listeria, a particularly dangerous pathogen which can cause food poisoning or even death in vulnerable populations such as the elderly, small children, and people with weakened immune systems. Scientists believe it may be possible to use naturally produced bacteriocins as a replacement for many of the "not-so-friendly" synthetic preservatives and additives commonly used today.

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Since emerging in 1997, the H5N1 influenza A virus, also known as the avian influenza virus, has proven to be a highly pathogenic microbe associated with a fatality rate of approximately 60% in humans. The H5N1 virus is resistant to most of the antiviral drugs currently available to treat the flu. Because of the potential danger of this microbe, researchers have been working towards the creation of a vaccine against the virus. Scientists have demonstrated that removing a specific part of one of the H5N1 virus proteins disrupts replication of the virus. More recently, scientists from the University of Wisconsin-Madison and the University of Tokyo found that vaccination with a mutant H5N1 virus that is missing this portion of the protein protects mice from a lethal dose of influenza virus. These findings may lead to the development of an effective vaccine against the H5N1 influenza A virus.

Primary Source: Watanabe, T. et al. (2008). Novel approach to the development of effective H5N1 influenza A virus vaccines: use of M2 cytoplasmic tail mutants. Journal of Virology, 82:2486-2492.

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For centuries, practitioners of traditional Chinese medicine have used a vegetable known as bitter melon as a cure for fatigue and other health issues. More recently, there has been speculation that bitter melon may be useful as a treatment for Type 2 diabetes. Now, researchers at the Garvan Institute of Medical Research and the Shanghai Institute of Materia Medica have uncovered what may be the molecular basis for the vegetable's reported efficacy as a diabetes treatment. They identified four compounds in bitter melon that appear to activate an enzyme known as 5'AMP-activated protein kinase (AMPK). This enzyme is known to play an important role in the transport of glucose (sugar) from the blood into cells. Individuals with Type 2 diabetes often produce low levels of insulin (a hormone that helps the body use glucose for energy) and are "insulin resistant," meaning their bodies do not respond effectively to normal insulin levels. By activating AMPK, thereby increasing the amount of glucose that enters cells, the compounds in bitter melon may help counteract the low insulin levels and insulin resistance that characterize Type 2 diabetes.

Primary Source: Tan, M. J. et al. (2008). Antidiabetic activities of triterpenoids isolated from bitter melon associated with activation of the AMPK pathway. Chemistry & Biology, 15: 263-273.

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Scientists at the Riken Institute in Tokyo report that, for the first time, rodents have been trained to use tools. The group trained South American rodents called degus (Octodon degus) to reach through a fence and use a tiny, rake-like tool to pull food within reach of their mouths. Once the degus had mastered the procedure, scientists performed further tests that indicated that the rodents not only could use the tools, they also had developed an understanding of the tool's functional and physical properties. The researchers have performed a series of similar experiments with Japanese macaques, a species that doesn't generally use tools in the wild. Their data suggests that as the monkeys learn to use tools, genes become active in a region of the brain that is important for the integration of vision and touch.  They will look for similar activity in the degu, an animal with excellent paw-and-eye coordination. Through these experiments, scientists hope to learn about the changes in the brain associated with the evolution of tool use and human intelligence.

Primary Source: Okanoya, K. et al. (2008). Tool-use training in a species of rodent: The emergence of an optimal motor strategy and functional understanding. PLoS ONE 3(3): e1860. doi:10.1371/journal.pone.0001860

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In recent years there has been growing concern about the unintended spread of genetically modified (GM) plants and the subsequent contamination of conventional crops. Now, researchers at Zhejiang University in China have discovered a simple and inexpensive method to selectively eliminate transgenic rice plants, thereby preventing the spread of their engineered genes. The strategy involves linking a small piece of genetic material, called an RNA interference (RNAi) cassette, with genes of interest in the transgenic rice. The RNAi cassette specifically suppresses the expression CYP81A6, an enzyme that is responsible for detoxification of the herbicide Bentazon in rice. While traditional rice is tolerant of Bentazon, which is commonly used for weed control in rice fields, genetically altered rice that lacks CYP81A6 is extremely vulnerable to the herbicide. As a result of this new technology, farmers can contain transgenic rice plants without additional cost or the need to introduce new, potentially harmful herbicides.

Primary source: Lin, C. et al. (2008). A built-in strategy for containment of transgenic plants: Creation of selectively terminable transgenic rice. PLoS ONE 3(3): e1818. doi:10.1371/journal.pone.0001818

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Although neuroscientists have known for years that people who have had a stroke have nearly double the risk of developing Alzheimer's disease, there was only speculation about possible mechanisms behind this correlation. Following stroke, there is an increase in the production of a toxic peptide known as amyloid beta (ABeta), which believed to cause Alzheimer's disease. Now, a team at Columbia University has discovered that this increase may result from enhanced activity of a specific molecular pathway. After an individual has a stroke, the production of another peptide, known as p25, also is increased in the brain. Higher levels of p25 appear to enhance the activity of an enzyme known as cyclin-dependent kinse 5 (cdk5). Researchers have evidence that the activation of this p25/cdk5 pathway may be behind the increased levels of toxic ABeta peptide seen in stroke victims and the associated risk of developing Alzheimer's disease.

Primary source: Wen, Y. et al. (2008). Transcriptional regulation of B-Secretase by p25/cdk5 leads to enhanced amyloidogenic processing. Neuron, 57: 680-690.

Mosquitoes are attracted to the scent of humans, specifically to sweaty body odor and carbon dioxide in breath. Now, scientists have determined that the most widely used insect repellent, DEET, works because it blocks the ability of mosquitoes to smell humans, thus providing humans with a chemical cloak that makes them invisible to mosquitoes and other blood sucking insects. This discovery may help guide the creation of new insect repellents based on the same principle, but without possible health concerns.

The insect repellent DEET has been around since 1946 when it was developed during World War II to prevent bites from mosquitoes and other blood-sucking insects in tropical warfare. DEET is very important in many developing countries because it repels mosquitoes that carry malaria, a leading killer of humans. It also repels ticks that spread Lyme disease.

Original Publication: Ditzen, M., Pellegrino, M. & Vosshall, L.B. (2008). Insect odorant receptors are molecular targets of the insect repellent DEET. Science.

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