January 22, 2010, 8:03 AM CT

Zebrafish helps drug development

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

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

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

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

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

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

January 15, 2010, 8:09 AM CT

Plant-pollinator relationship

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

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

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

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

January 15, 2010, 8:04 AM CT

Impact of eucalyptus plantations on the ecology of rivers

A team from the Department of Plant Biology and Ecology at the University of the Basque Country (UPV/EHU) are focusing their research on the study of the ecology of rivers. The person in charge is Mr Jesús Pozo. For more than twenty years this team has been trying to identify links between the ecology and functioning of rivers and the surrounding terrestrial environment because, when all is said and done, rivers are like the excretory apparatus of the continents, just like the kidney is to the human body. River water often reflect the state of health of the external environment.

Within this line of research, the UPV/EHU team is focusing on studying the possible impact of the afforestation of exotic species on the functioning of rivers, both on the chemistry of the water as well as on the communities of organisms therein. An exotic species is a species introduced outside its normal area of distribution, for example, the eucalyptus - the case in hand.

Rivers of any specific geographical environment have a natural riverside type of vegetation and the community of organisms in the river is accustomed to consuming the dead leaves and foliage that enter the water from this surrounding vegetation. When this natural vegetation (in this case deciduous woods) are substituted by exotic plantations the quality of this plant material changes and the community of river organisms have to deal with the use or otherwise of this non-autochthonous organic material. This use or not by the aquatic organisms of the new material entering the river system can have certain repercussions, both on the organisms themselves and on processes occurring in the river......... Posted by: Erica      Read more         Source

January 14, 2010, 8:11 AM CT

Why leopards can't change their spots

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

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

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

January 14, 2010, 8:10 AM CT

Tracking paw prints of selective breeding

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

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

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

January 14, 2010, 8:00 AM CT

Sequencing of soybean genome

Soybean, one of the most important global sources of protein and oil, is now the first major crop legume species with a published complete draft genome sequence. This sequence, which essentially provides a parts list of the soybean genome, will help researchers use the plant's genes to improve its characteristics. The soybean sequencing study appears as the cover story of the January 13 edition of Nature



Value of the new soybean sequence

Researchers will use the new sequence to identify which genes are responsible for particular plant characteristics, and then target specific genes to produce desired characteristics. These desired characteristics may include increases in the plant's oil content to promote the use of soybean oil as a biofuel; bigger crops; improved resistance to pests and diseases that currently claim large percentages of soybean crops; improvements in the digestibility of soybeans by animals and humans; and reductions in contaminants present in the manure of soybean-fed swine and poultry that may pollute farm runoff.

The research team plans to identify which soybean genes warrant targeting by:

• Comparing the genomes of different varieties of soybean plants to one another.
• Resequencing 20,000 soybean lines that are currently stored in the National Plant Germplasm System to identify desired variances of genes that are not currently captured by domesticated soybean lines.

........ Posted by: Erica      Read more         Source

January 13, 2010, 8:16 AM CT

Tilapia feed on Fiji's native fish

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

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

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

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

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

January 12, 2010, 8:47 AM CT

Impacts of Climate and Development

California butterflies are reeling from a one-two punch of climate change and land development, says an unprecedented analysis led by UC Davis butterfly expert Arthur Shapiro.

The new analysis, scheduled to be published online this week in the journal Proceedings of the National Academy of Sciences, gives insights on how a major and much-studied group of organisms is reacting to the Earth's warming climate.

"Butterflies are not only charismatic to the public, but also widely used as indicators of the health of the environment worldwide," said Shapiro, a professor of evolution and ecology. "We found a number of lowland species are being hit hard by the combination of warmer temperatures and habitat loss".

The results are drawn from Shapiro's 35-year database of butterfly observations made twice monthly at 10 sites in north-central California from sea level to tree line. The Shapiro butterfly database is unique in science for its combination of attributes: one observer (which reduces errors), very long-term, multiple sites surveyed often, a large number of species (more than 150), and attendant climatological data.

Shapiro's co-authors include three other UC Davis scientists and two former Shapiro graduate students, including lead analyst Matthew Forister, now an assistant professor of biology at the University of Nevada, Reno......... Posted by: Kelly      Read more         Source

January 12, 2010, 8:43 AM CT

Cricket as an orchid pollinator

An orchid researcher based on the island of Reunion in the Indian Ocean and collaborating with scientists at the Royal Botanic Gardens, Kew (RBG Kew) has used motion sensitive night cameras to capture the first known occurrence of a cricket functioning as a pollinator of flowering plants. Not only is this the first time this behaviour has been documented in a member of the Orthoptera order of insects who are better known for eating plants but the 'raspy cricket' is also entirely new to science. The discovery is revealed in a paper published recently (12 January 2010) in Annals of Botany

In 2008 Claire Micheneau, a RBG Kew-associated PhD student studying how the epiphytic orchid genus Angraecum has adapted to different pollinators on Reunion Island, and Jacques Fournel, her collaborator, shot the remarkable footage. It shows a raspy cricket (Glomeremus sp) carrying pollen on its head as it retreats from the greenish-white flowers of Angraecum cadetii

The genus Angraecum is best known for Darwin's study of the comet orchid, Angraecum sesquipedale of Madagascar, and his hypothesis that it was pollinated by a bizarre, long-tongued moth pollinator a theory that was later proved to be true a number of years after his death......... Posted by: Kelly      Read more         Source

January 11, 2010, 8:05 AM CT

About salmon migration

A new acoustic telemetry system tracks the migration of juvenile salmon using one-tenth as a number of fish as comparable methods, suggests a paper reported in the January edition of the American Fisheries Society journal Fisheries The paper also explains how the system is best suited for deep, fast-moving rivers and can detect fish movement in more places than other tracking methods.

The Juvenile Salmon Acoustic Telemetry System (JSATS) estimated the survival of young, ocean-bound salmon more precisely than the widely used Passive Integrated Transponder (PIT) tags during a 2008 study on the Columbia and Snake rivers, as per the results of a case study discussed in the paper. The paper also concludes that fish behavior is affected least by light-weight JSATS tags in comparison to larger acoustic tags.

"Fisheries managers and scientists have a number of technologies to choose from when they study fish migration and survival," said main author Geoff McMichael of the Department of Energy's Pacific Northwest National Laboratory.

"JSATS was specifically designed to understand juvenile salmon passage and survival through the swift currents and noisy hydroelectric dams on the Columbia River," McMichael continued. "But other systems might work better in different circumstances. This paper demonstrates JSATS' strengths and helps scientists weigh the pros and cons of the different fish tracking methods available today"......... Posted by: Kelly      Read more         Source