September 17, 2009, 11:54 PM CT

Salmon migration mystery explored

Temperature differences and slow-moving water at the confluence of the Clearwater and Snake rivers in Idaho might delay the migration of threatened juvenile salmon and allow them to grow larger before reaching the Pacific Ocean.

A team of Northwest scientists are examining the unusual life cycle of the Clearwater's fall Chinook salmon to find out why some of them spend extra time in the cool Clearwater before braving the warm Snake. The Clearwater averages about 53 degrees Fahrenheit in the summer, while the Snake averages about 71. The confluence is part of the Lower Granite Reservoir - one of several sections of slow water that are backed up behind lower Snake and Columbia river dams - that could reduce fish's cues to swim downstream.

The delayed migration could also mean Clearwater salmon are more robust and survive better when they finish their ocean-bound trek, said Billy Connor, a fish biologist with the U.S. Fish & Wildlife Service.

"It may seem counterintuitive, but the stalled migration of some salmon could actually help them survive better," Connor said. "Juvenile salmon may gamble on being able to dodge predators in reservoirs so they can feast on the reservoirs' rich food, which allows them to grow fast. By the time they swim toward the ocean the next spring, they're bigger and more likely to survive predator attacks and dam passage"......... Posted by: Kelly      Read more         Source

September 15, 2009, 9:23 PM CT

Unlocking genetic secrets of date palm

Scientists at Weill Cornell Medical College in Qatar have mapped a draft version of the date palm genome, unlocking a number of of its genetic secrets.

"We have generated a draft DNA sequence and initial assembly of the date palm using the most advanced technology," says Joel Malek, director of the Genomics Laboratory at WCMC-Q. Genetic information about the date palm is extremely valuable to scientists who are working to improve fruit yield and quality and to better understand susceptibility and resistance to disease.

"This is an important step for our biomedical research program," says Khaled Machaca, Ph.D., professor of physiology and biophysics and associate dean for basic science research. "It clearly demonstrates the feasibility and success of the most advanced genomics technologies in Qatar and represents a milestone towards establishing Qatar and Weill Cornell as a regional research center of excellence. In addition, this achievement by the WCMC-Q research team holds great promise for the application of the genomics technology to a better understanding of biomedical problems".

The date palm sequencing work was a proof of concept study, as per Malek, who established the genomics laboratory last year. The goal was to establish and validate the capabilities of the core lab for large-scale genomics projects. The lab is an integral part of a large biomedical research program launched last year by WCMC-Q with support from the Qatar Foundation that aims to make Qatar a hub for research in the Middle East......... Posted by: Erica      Read more         Source

September 15, 2009, 9:19 PM CT

Drug-free Cannabis plant

In a first step toward engineering a drug-free Cannabis plant for hemp fiber and oil, University of Minnesota scientists have identified genes producing tetrahydrocannabinol (THC), the psychoactive substance in marijuana. Studying the genes could also lead to new and better drugs for pain, nausea and other conditions.

The finding is reported in the recent issue of the Journal of Experimental Botany Main author is David Marks, a professor of plant biology in the College of Biological Sciences.

The study revealed that the genes are active in tiny hairs covering the flowers of Cannabis plants. In marijuana, the hairs accumulate high amounts of THC, whereas in hemp the hairs have little. Hemp and marijuana are difficult to distinguish apart from differences in THC.

With the genes identified, finding a way to silence themand thus produce a drug-free plant comes a step closer to reality. Another desirable step is to make drug-free plants visually recognizable. Since the hairs can be seen with a magnifying glass, this could be accomplished by engineering a hairless Cannabis plant.

The scientists are currently using the methods of the latest study to identify genes that lead to hair growth in hopes of silencing them.

"We are beginning to understand which genes control hair growth in other plants, and the resources created in our study will allow us to look for similar genes in Cannabis sativa," said Marks......... Posted by: Erica      Read more         Source

September 15, 2009, 2:45 PM CT

Exotic timber plantations use water

Ecologists have discovered that timber plantations in Hawaii use more than twice the amount of water to grow as native forests use. Particularly for island ecosystems, these findings suggest that land management decisions can place ecosystems and the people who depend on them at high risk for water shortages.

"Researchers used to believe that forests in same environments use water in the same way," says Lawren Sack of The University of California at Los Angeles, who coauthored the study with graduate student Aurora Kagawa in the recent issue of the ESA journal Ecological Applications "Our work shows that this is not the case. We need to know the water budget of our landscape, from gardens to forests to parks, because water is expensive".

Eventhough forests like these Hawaiian timber plantations can be valuable for their contributions to human society, such as fiber, fuel and carbon sequestration, they are dominated by non-native vegetation.

Kagawa, Sack and their colleagues compared the water use of trees in native forests, composed mostly of native ohia trees, with water use in timber plantations containing exotic eucalyptus and tropical ash. The team inserted heated and unheated probes into the trees' trunks and monitored the temperature differences between the two as sap flowed past them. This technique allowed them to determine the rate of sap flow through the tree. A faster flow rate means that the tree is using more water......... Posted by: Erica      Read more         Source

September 15, 2009, 2:36 PM CT

New Sequencing Technique Could Boost Pine Beetle Fight,

September 15, 2009.

UBC scientists have helped developed a cheaper, faster way to compile draft genome sequences that could advance the fight against mountain pine beetle (MPB) infestation and improve cancer research.

Current sequencing methods have a variety of advantages and disadvantages--including the cost involved. Dr Steven Jones and his colleagues at UBC, the BC Cancer Agency and Simon Fraser University have combined cutting edge hardware with novel software to compile genome sequences at a fraction of the cost of prior methods.

The technique is outlined in the current issue of the journal Genome Biology.

Using the new approach, the research team--which also includes UBC's Joerg Bohlmann, Colette Breuil and Richard Hamelin--has compiled the first complete genome sequence of a fungus (Grosmannia clavigera) that is key to the mountain pine beetle infestation process.

"The key to better preparedness for future forest health crises such as the current mountain pine beetle epidemic lies in better understanding of the three main players-the trees, the bark beetles and a fungus-and their complex interactions," said Bohlmann, Distinguished University Scholar and professor at UBC's Michael Smith Laboratories.

"The infestation has affected 10 to 14 million hectares of pine forests in British Columbia. We can't fight an enemy if we don't know what it's made of. The complete genome of the fungus brings us one step closer to winning the battle"......... Posted by: Kelly      Read more         Source

September 15, 2009, 2:29 PM CT

More tamarisk invasion in future

If the future warming trends that researchers have projected are realized, one of the country's most aggressive exotic plants will have the potential to invade more U.S. land area, as per a newly released study reported in the current issue of the journal Invasive Plant Science and Management The study observed that tamariskprevalent today in some parts of the region, but generally limited to warm and dry environmentscould expand its range into currently uninvaded areas.

"Results of our study suggest that a little over 20 percent of the Northwest east of the Cascade Mountains supports suitable tamarisk habitat, but less than one percent of these areas is currently occupied by the species," said Becky Kerns, a research ecologist with the Western Wildland Environmental Threat Evaluation Center (WWETAC) who led the study. "That means the remainder is highly vulnerable to invasion right now with the situation potentially getting worse as favorable conditions for tamarisk may expand under climate change".

These findings translate into a two- to ten-fold increase in highly suitable tamarisk habitat in Oregon, Washington, and Idaho by the end of the century.

Tamarisk, also known as "saltcedar," is a deciduous shrub or small tree that grows quickly, reproduces profusely, and tolerates drought and salty conditions, making it capable of easily displacing native species. It also sheds flammable leaves that serve as potential fuel, significantly increasing an area's wildfire risk. The plant was intentionally introduced to the West in the 1800s as an ornamental, windbreak, shade, and erosion control species and today can be found growing prolifically in the Northwest in the central Snake River Plain, Columbia Plateau, and Northern Basin and Range......... Posted by: Erica      Read more         Source

September 15, 2009, 7:51 AM CT

Clues into the evolution of the first flowers

Approximately 120-130 million years ago, one of the most significant events in the history of the Earth occurred: the first flowering plants, or angiosperms, arose. In the late 1800s, Darwin referred to their development as an "abominable mystery." To this day, researchers are still challenged by this "mystery" of how angiosperms originated, rapidly diversified, and rose to dominance. (See the January 2009 issue of the American Journal of Botany at www.amjbot.org/content/vol96/issue1.).

Studies of key features of angiosperm evolution, such as the evolution of the flower and development of the endosperm, have contributed to our current understanding of relationships among the early families of flowering plants. Examining the development of seeds and embryos among early angiosperms may help to improve our understanding of how flowering plants evolved from the nonflowering gymnosperms.

A recent study by Dr. Paula Rudall and his colleagues reported in the recent issue of the AJB (www.amjbot.org/cgi/content/full/96/9/1581) explores a piece of this mystery: the microscopic anatomy of seed development in Trithuria, a genus in the plant family Hydatellaceae, believed to be one of the earliest families of angiospermsthe so-called "basal angiosperms".

Rudall and his colleagues' observations of the development of the embryo and endosperm (tissue that surrounds the embryo and provides nutrition) in Trithuria suggest that double fertilization occurs. Double fertilization is a unique feature of flowering plants where one sperm nucleus unites with the egg, producing the embryo, while another sperm nucleus unites with a separate nucleus from the female, producing the endosperm. The endosperm is divided into two regionsthe micropylar and chalazal regions......... Posted by: Erica      Read more         Source

September 15, 2009, 7:47 AM CT

Barcoding endangered sea turtles

Conservation geneticists who study sea turtles have a new tool to help track this highly migratory and endangered group of marine animals: DNA barcodes. DNA barcodes are short genetic sequences that efficiently distinguish species from each othereven if the samples from which the DNA is extracted are minute or degraded. Now, a recently published research paper by researchers from the American Museum of Natural History and the University of Canberra, among other organizations, demonstrates that this technology can be applied to all seven sea turtle species and can provide insight into the genetic structure of a widely-dispersed and ancient group of animals.

"This is the first study to document DNA barcodes of all species of sea turtles from around the world," says Eugenia Naro-Maciel, Marine Biodiversity Scientist at the Center for Biodiversity and Conservation at the Museum and first author of the paper reported in the early online edition of Molecular Ecology Resources "These barcodes can be used to document biological diversity in a standardized fashion and for the conservation of these charismatic and ecologically important marine animals".

DNA barcodes are relatively short segments of mitochondrial DNA. A region of the COI, or cox1 gene (cytochrome c oxidase subunit 1) has been agreed-upon by scientists as appropriate for barcoding, given that it is both highly variable and very specific. This portion of the genome mutates quickly enough to distinguish a number of closely related species but also slowly enough so that individuals within a species may have similar barcodes. Barcoding has been used to check the accuracy of caviar and red snapper labeling and to identify the presence of endangered whales in Asian markets, as well as other applications......... Posted by: Kelly      Read more         Source

September 15, 2009, 7:45 AM CT

Conflict between plant and animal hormones

Cis-OPDA (12-oxophytodienoic acid) is a highly reactive plant hormone which simultaneously serves as a precursor molecule of the metabolic "master switch" jasmonic acid. Both signal herbivory in leaves and shoots of plants and activate the plants' defense reaction against caterpillars. Cis-OPDA, when reaching the hemolymph of the caterpillar, has a negative effect on the animal, leading to premature pupation and, apparently, an impaired immune system.

Paulina Dabrowska, one of the very first PhD students of the Jena International Max Planck Research School (IMPRS) who meanwhile earned her PhD, studied the whereabouts of plant hormones after they had been consumed by the caterpillars and had passed the insect gut. Are the hormones, which are known to severely influence development and metabolism of organisms even in the slightest dose, fully metabolized in the insect gut, just converted, or not influenced at all?

Studying the plant hormone cis-OPDA it became quickly evident that a conversion of the molecule must have taken place in the insect gut. The young chemist, originally from Poland, discovered that an enzyme must play a role in the chemical reaction observed: "First, we observed that cis-OPDA was not present in the insect feces anymore. Instead of cis-OPDA, our mass spectrometers suggested iso-OPDA. However, iso-OPDA is only constituted by means of enzyme catalysis." Control experiments, solely performed in strong alkaline solutions as present in the insect gut (pH approx. 10), did not cause a cis-iso conversion. The test animals were Spodoptera littoralis (cotton leaf worm) and Helicoverpa armigera (cotton bollworm) larvae; both species are major cotton pests worldwide......... Posted by: Erica      Read more         Source

September 15, 2009, 7:43 AM CT

'Metacognition' in Some Animals

J. David Smith, Ph.D., a comparative psychology expert at the University at Buffalo who has conducted extensive studies in animal cognition, says there is growing evidence that animals share functional parallels with human conscious metacognition -- that is, they may share humans' ability to reflect upon, monitor or regulate their states of mind.

Smith makes this conclusion in an article published the recent issue of the journal Trends in Cognitive Science (Volume 13, Issue 9). He reviews this new and rapidly developing area of comparative inquiry, describing its milestones and its prospects for continued progress.

He says "comparative psychology experts have studied the question of whether or not non-human animals have knowledge of their own cognitive states by testing a dolphin, pigeons, rats, monkeys and apes using perception, memory and food-concealment paradigms.

"The field offers growing evidence that some animals have functional parallels to humans' consciousness and to humans' cognitive self-awareness," he says. Among these species are dolphins and macaque monkeys (an Old World monkey species).

Smith recounts the original animal-metacognition experiment with Natua the dolphin. "When uncertain, the dolphin clearly hesitated and wavered between his two possible responses," he says, "but when certain, he swam toward his chosen response so fast that his bow wave would soak the researchers' electronic switches......... Posted by: Kelly      Read more         Source