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September 19, 2006
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Cool Image: Cellular Polarity
As an egg cell develops, a process called polarization controls
what parts ultimately become the embryo's head and tail. This
picture shows an egg of the fruit fly Drosophila.
Red and green mark two types of signaling proteins involved
in polarization. Disrupting these signals can scramble the
body plan of the embryo, leading to severe developmental disorders.
Courtesy of Wu-Min Deng, a developmental biologist at Florida
lab home page
Article abstract (from the August 22, 2006, issue of PNAS)
Catching Cancer Before it Kills
Many cancers aren't discovered until they've formed large tumors or spread to other organs, making them difficult to treat. A research team led by Weihong Tan, a chemist at the University of Florida, has developed a technique that spots cancer's molecular signature long before the disease can be detected by current methods. The technique uses short strands of DNA called aptamers that can distinguish cancer cells from healthy ones based on differences in molecules on their surfaces. If the technique works in further tests, it could help improve cancer diagnosis and treatment.
Full story (no longer available)
lab home page
Article abstract (from the August 8, 2006, issue of PNAS)
Genome Sequence Reveals Basis of Tetrahymena's Versatility
Caption: Tetrahymena thermophila with the cilia shown in green and one of the organism's two nuclei, shown in blue. Courtesy of Eduardo Orias.
For a single-celled organism, the microscopic, pond-living
creature Tetrahymena thermophila is remarkably sophisticated.
It can forage for food using diverse sensory systems, protect
itself from radiation, and defend against predators. The recent
completion of a Tetrahymena genome sequence, led
by evolutionary biologist Jonathan Eisen while at The Institute
for Genomic Research in Maryland, sheds light on the basis
for this impressive versatility. Tetrahymena has
more than 25,000 genes—roughly the same number as humans—and
many are devoted to sensing and responding to the environment.
The availability of Tetrahymena's genome sequence
promises further insights into this popular model organism
for studying eukaryotic cell biology.
Article (from the September 2006 issue of PLoS Biology)
Important Step Toward RNA-Based Cancer Drug
Understanding—and harnessing—RNA's many abilities is one of the hottest fields in biomedical research. Recently, molecular biologist Bruce Sullenger and his research team at Duke University Medical Center overcame major technical hurdles to develop an experimental, RNA-based drug that kills cancer cells in mice while leaving neighboring normal cells alone. The drug is made up of two kinds of RNA that work in tandem. A "targeting" RNA coerces cancer cells to let the drug in, and a "silencing" RNA marks for destruction a specific protein needed for the cancer cell to survive. The drug shrank mouse prostate tumors by half without causing any adverse side effects, while untreated tumors more than tripled in size. If scientists can solve challenges in administering therapeutic RNA and Sullenger's drug works equally well in humans, this work could represent an important first step toward developing an RNA-based anticancer medicine.
Sullenger home page
Article abstract (from the August 2006 issue of Nature Biotechnology)
Zebrafish Reveal New Path for Treating Rare Disorder
Normal zebrafish embryo (top); zebrafish embryo with mutation disrupting copper metabolism (bottom). Courtesy of Solnica-Krezel.
A hardy, tropical fish striped like a zebra is popular with aquarists, but the creature's unique features—like transparent eggs and embryos—also make it a favorite among scientists. A research team that included developmental geneticist Lilianna Solnica-Krezel of Vanderbilt University and geneticist Stephen Johnson of Washington University in St. Louis recently found that a specific mutation in a zebrafish gene disrupts the metabolism of copper, an important nutrient. The disruption impedes normal development and causes a number of defects resembling those seen in children with Menkes disease, a rare but fatal genetic disorder caused by improper copper metabolism. The research also showed that both humans and zebrafish have similar molecular mechanisms for copper metabolism, suggesting that the striped fish could be used to screen potential new drugs to treat the human disorder.
story (No longer available)
lab home page
Article abstract (from the August 2006 issue of Cell Metabolism)