October 1, 2006, 8:09 PM CT

Cloned mice created from non-stem cell

Did you know that stem cells are not actually required for cloning?

New research dismisses the notion that adult stem cells are necessary for successful animal cloning, proving instead that cells that have completely evolved to a specific type not only can be used for cloning purposes, but they may be a better and more efficient starting point. As proof, researchers report they created two mouse pups from a type of blood cell that itself is incapable of dividing to produce a second generation of its own kind.

This is the first demonstration that an animal can be derived directly from a fully differentiated cell, report lead researchers Xiangzhong (Jerry) Yang, Ph.D., of the University of Connecticut, and Tao Cheng, M.D., of the University of Pittsburgh, in the journal Nature Genetics. Moreover, they say results of their studies provide compelling evidence that Dolly the sheep and other mammals cloned by somatic cell nuclear transfer were most likely derived from fully differentiated cells, not adult stem cells, as most have argued in the nine years since Dolly was first created. Because stem cells have the ability to self-renew and differentiate into any specialized cell type, they have been heralded for their promise for treating a variety of diseases and conditions. Yet, even for cloning of an embryo to the blastocyst stage, from which embryonic stem cells can be generated, adult stem cells have yielded disappointing results, with success rates in the range of 1 to 5 percent.........

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October 1, 2006, 7:12 PM CT

Stellar Birth Control

Is birth control in effect in the universe?

An international team of astronomers based at Yale and Leiden University in The Netherlands observed that "old stars" dominated a number of large galaxies in the early universe, raising the new question of why these galaxies progressed into "adulthood" so early in the life of the universe.

Every year only a handful of new stars are born out of the gas that fills the space between the stars in galaxies like the Milky Way. To account for the large number of stars in the Universe today, about 400 billion in the Milky Way alone, it was thought that the "stellar birth rate" must have been much higher in the past.

Surprisingly, in this study appearing in the October 2 issue of Astrophysical Journal, astronomers using the 8.1m Gemini telescope in Chile report that a number of of the largest galaxies in the Universe had a very low stellar birth rate even when the Universe was only about 20 percent of its present age.

"Our new results imply that the stars in a number of large galaxies were born when the Universe was in its infancy, in the first few billion years after the Big Bang," said team leader Mariska Kriek, a PhD student from Leiden University and Yale. "The results confirm what some astronomers had suspected -- galaxies seem to have some method of 'birth control' that is very effective".........

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September 28, 2006, 9:30 PM CT

Live Oak Trees Struggle For Survival

The majestic live oak is losing its battle for survival to suburban sprawl and the encroachment of taller trees, a new University of Florida study finds.

An icon in American history and literature, broad-crowned live oaks thrive in open savannas but are dying off as they are crowded and overshadowed by the encroachment of taller trees, said Francis Putz, a UF botanist and the study's co-author.

It is an irony of nature that the successes of reforestation and urban forestry threaten live oaks, which in the past maintained the elbow room they needed from logging, cattle grazing and frequent fires, said Putz, whose work is published in the recent issue of Forest Ecology and Management. "We are confusing our natural savanna heritage with forested landscapes and the tragedy is that the forest is killing live oaks," he said. "If we allow other trees to grow up too close to the live oak, the live oak will die. Our research clearly establishes this fate in both rural and suburban landscapes".

The live oak's broad crown, with long arching limbs that spread horizontally rather than vertically, as most trees do, give it a distinctive architectural makeup, said Tova Spector, who did the study with Putz as part of her master's degree in ecology. "Trees that grow straight and tall crowd the live oaks, causing their crowns to die back," she said.........

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September 28, 2006, 9:26 PM CT

Improbable Buckyegg Hatched

An egg-shaped fullerene, or "buckyball egg" has been made and characterized by chemists at UC Davis, Virginia Tech and Emory and Henry College, Va. The unexpected discovery opens new possibilities for structures for fullerenes, which could have a wide range of uses.

"It was a total surprise," said Christine Beavers, a chemistry graduate student working with Professors Alan Balch and Marilyn Olmstead at UC Davis. Beavers is first author on the paper, published this month in the Journal of the American Chemical Society.

Fullerenes, sometimes called "buckyballs," are usually spherical molecules of carbon, named after the futurist R. Buckminster Fuller, inventor of the geodesic dome. The carbon atoms are arranged in pentagons and hexagons, so their structures can resemble a soccer ball. An important rule -- until now -- is that no two pentagons can touch, but are always surrounded by hexagons.

The "buckyegg" compound was made by collaborating scientists at Virginia Tech, led by Professor Harry Dorn. They heated a mixture of carbon and other ingredients under special conditions to make a mixture of fullerenes, then shipped the products to UC Davis, where Balch's group worked on characterizing their structures.

When Beavers started to map out the structure, she found two pentagons next to each other, making the pointy end of the egg. Initially she thought that the results were a mistake, but she showed the data to Marilyn Olmstead, an expert on X-ray crystallography, and they decided that the results were real. The egg contains a molecule of triterbium nitride inside.........

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September 28, 2006, 8:38 PM CT

Membranes At The Nanoscale

The composition of lipid membranes, similar to those that surround living cells, can now be mapped at the nanometer scale. The work, by researchers at Stanford University, the Lawrence Livermore National Laboratory and UC Davis, is published in the Sept. 29 issue of the journal Science.

All living cells are wrapped in a double-layered membrane of fatty lipid molecules. Components of the membrane can move sideways and organize into patches or other structures. This organization can affect, for example, important cell functions and vulnerability to viruses.

But it is very difficult to study these structures because they are so small, measured in tens of nanometers, said Marjorie Longo, professor of chemical engineering and materials science at UC Davis. A nanometer is a billionth of a meter, or about a thirty-millionth of an inch. Scientists want to address questions such as how dynamic or active the membrane is and how small the lipid patches are, she said. An atomic force microscope, which uses a fine needle to probe surfaces, can give a contour map of the surface but without chemical information.

The research group, led by Steven Boxer of Stanford University, used a highly focused beam of charged particles to scan the surface of artificial lipid membranes containing lipid patches developed in Longo's lab. Components of the membrane were previously labeled with heavy isotopes of carbon and nitrogen, mounted on silicon wafers and flash-freeze-dried to preserve structure.........

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September 26, 2006, 8:48 PM CT

Quantum Encryption Over Record Distances

Using an innovative sensor for detecting single photons, the smallest particles of light, scientists from Los Alamos National Laboratory (LANL), the National Institute of Standards and Technology (NIST) and Albion College (Albion, Mich.) have set two significant distance records for distributing "keys" (or codes) for quantum encryption, the most secure method known for protecting the privacy of information.

As described in the recent issue of New Journal of Physics,* the team generated and transmitted secret quantum keys over 184.6 kilometers (km) of fiber-optic cable, the longest distance ever recorded for quantum key distribution (QKD). The previous record was 122 km. Secret quantum key is a code for encrypting data that not only have been transmitted and detected successfully, but also processed to correct for errors and enhance privacy, steps considered essential for practical applications. The keys are then used to encrypt ordinary digital data for transmission over conventional communications channels.

"This work extends the potential range of one link of a quantum communications system," says Sae Woo Nam, the NIST physicist who designed the photon detectors. "Experiments like this are interesting because they establish new thresholds for the distance between repeaters," or devices that re-send and boost fading signals between links in far-reaching networks.........

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September 25, 2006, 10:16 PM CT

Most Complex Protein Knot Ever Seen

An MIT team has discovered the most complicated knot ever seen in a protein, and they believe it may be linked to the protein's function as a rescue agent for proteins marked for destruction.

"In proteins, the three-dimensional structure is very important to the function, and this is just one example," said Peter Virnau, a postdoctoral fellow in physics and an author of a paper on the work that appears in the Sept. 15 issue of the Public Library of Science, Computational Biology.

Knots are rare in proteins - less than 1 percent of all proteins have any knots, and most are fairly simple. The researchers analyzed 32,853 proteins, using a computational technique never before applied to proteins at this scale.

Of those that had knots, all were enzymes. Most had a simple three-crossing, or trefoil knot, a few had four crossings, and the most complicated, a five-crossing knot, was initially found in only one protein - ubiquitin hydrolase.

That complex knot may hold some protective value for ubiquitin hydrolase, whose function is to rescue other proteins from being destroyed - a dangerous job.

When a protein in a cell needs to be destroyed, it gets labeled with another protein called ubiquitin. "It's a death mark for the protein," said Leonid Mirny, an author of the paper and an associate professor in the MIT-Harvard Division of Health Sciences and Technology.........

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September 25, 2006, 9:43 PM CT

Avian Flu Vaccine Provokes Strong Immune Response

When combined with an immune-boosting substance called an adjuvant, low doses of an experimental vaccine against a strain of avian influenza (H9N2) provoked a strong antibody response in human volunteers, report researchers supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

The clinical trial of 96 adults was conducted at the NIAID-supported Viral Respiratory Pathogens Research Unit at Baylor College of Medicine, Houston, and was led by Robert L. Atmar, M.D. The results are now online in Clinical Infectious Diseases.

"The results of this clinical trial add to the growing body of information demonstrating the potential value of adjuvanted avian influenza vaccines," says NIAID Director Anthony S. Fauci, M.D. An adjuvant is a substance that is added to a vaccine to boost the body's immune response to the vaccine's antigen. "In the event of an influenza pandemic, adjuvanted vaccines could provide a way to extend a limited vaccine supply to more people," he adds.

In 1999, two children in Hong Kong became infected with H9N2, a strain of avian influenza that had not previously been detected in humans. Humans have little or no natural immunity to a virus--such as H9N2 or the more deadly H5N1 avian influenza--that historically has circulated only in birds. If H9N2 or H5N1 were to acquire the ability to spread easily from person to person, an influenza pandemic could result, health experts say.........

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September 25, 2006, 9:37 PM CT

New Study For Multiple Sclerosis

Acorda Therapeutics, Inc. today announced positive results from its Phase 3 clinical trial of Fampridine-SR on walking in people with multiple sclerosis (MS). Statistical significance was achieved on all three efficacy criteria defined in the Special Protocol Assessment (SPA) by the Food and Drug Administration (FDA). A significantly greater proportion of people taking Fampridine-SR had a consistent improvement in walking speed, the study's primary outcome, compared to people taking placebo (34.8 percent vs. 8.3 percent) as measured by the Timed 25-Foot Walk (p less than 0.001). In addition, the effect was maintained in this study throughout the 14-week treatment period (p less than 0.001) and there was a statistically significant improvement in the 12-Item MS Walking Scale (MSWS-12) for walking responders vs. non-responders (p less than0.001).

The average increase in walking speed over the treatment period compared to baseline was 25.2 percent for the drug group vs. 4.7 percent for the placebo group. Increased response rate on the Timed 25-Foot Walk was seen across all four major types of MS. In addition, statistically significant increases in leg strength were seen in both the Fampridine-SR Timed Walk responders (p<0.001) and the Fampridine-SR Timed Walk non-responders (p=0.046) compared to placebo. The Company intends to present comprehensive data at an upcoming medical meeting.........

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September 25, 2006, 9:27 PM CT

World Warmth Going To Ancient Levels

A new study by NASA climatologists finds that the world's temperature is reaching a level that has not been seen in thousands of years.

The study appears in the current issue of the Proceedings of the National Academy of Sciences, authored by James Hansen of NASA's Goddard Institute for Space Studies, N.Y. and colleagues from Columbia University, Sigma Space Partners, Inc., and the University of California at Santa Barbara (UCSB). The study concludes that, because of a rapid warming trend over the past 30 years, the Earth is now reaching and passing through the warmest levels in the current interglacial period, which has lasted nearly 12,000 years. This warming is forcing a migration of plant and animal species toward the poles.

The study includes worldwide instrumental temperature measurements during the past century. These data reveal that the Earth has been warming at the remarkably rapid rate of approximately 0.2 degree Celsius (.36 degree Fahrenheit) per decade for the past 30 years. This observed warming is similar to the warming rate predicted in the 1980s in initial global climate model simulations with changing levels of greenhouse gases.

"This evidence implies that we are getting close to dangerous levels of human-made (anthropogenic) pollution," said Hansen. In recent decades, human-made greenhouse gases (GHGs) have become the dominant climate change factor.........

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