Biomedical Beat - A monthly digest of research news from NIGMS

IN THIS ISSUE . . .
May 20, 2009

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Cool Image: Sleepy Head

Courtesy of University of Wisconsin-Madison neuroscientist Chiara Cirelli.
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(JPEG, 195 KB)

Hover over the image to see two snapshots of the fruit fly brain. In the first, the brain of a sleep-deprived fly glows orange, marking high concentrations of a synaptic protein involved in communication between neurons. The color also lights up three brain areas associated with learning. By contrast, the second image from a well-rested fly has lower levels of the protein. These pictures illustrate the results of a recent study showing that sleep reduces the protein’s levels, suggesting that such “downscaling” resets the brain to normal levels of synaptic activity and makes it ready to learn after a restful night. Courtesy of University of Wisconsin-Madison neuroscientist Chiara Cirelli.

Full story
Cirelli profile
Cirelli lab
Article abstract (from the April 3 issue of Science)

New, Long-Lasting Way to Numb Pain

Photograph of surgeons around a patient.
A long-lasting local anesthetic could revolutionize pain treatment.

Most anesthesia comes in two flavors: the long-acting, body-wide type that knocks you out for surgery, and the local type that wears off as you leave the dentist’s office. Now, researchers have created a long-sought third flavor. The scientists, led by pediatric critical care specialist Daniel Kohane of Children’s Hospital Boston, created tiny bubbles that slowly release a potent local anesthetic. In rats, the anesthetic lasted for several days and didn’t cause nerve damage or other side effects. If the technique works as well in humans, it could revolutionize the treatment of surgical pain and the management of chronic pain.

Full story (no longer available)
Kohane profile
Article abstract (from the April 13 online issue of PNAS)

Second Flu Antiviral Limits Drug Resistance

An influenza virus particle. Courtesy of Cynthia Goldsmith.
An influenza virus particle. Courtesy of Cynthia Goldsmith.
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The emerging H1N1 flu strain reminds us that an influenza pandemic is possible, and many countries have already stockpiled an antiviral medication. But widespread use of a single medicine could generate a drug resistant strain. A team, led by Joseph Wu of the University of Hong Kong and including MIDAS researcher Marc Lipsitch of the Harvard School of Public Health, used a mathematical model to show that treating a small number of infected individuals with a second drug during the early phase of a local epidemic could substantially delay the development of resistance. The model also showed that the localized strategy could benefit distant parts of the world.

Full story
Wu profile
Lipsitch profile
Models of Infectious Disease Agent Study (MIDAS)
Article (from the April 30 early edition of PLoS Medicine)

‘Extremophile’ Evolves Strange Molecular Trick

Structure of Methanopyrus kandleri's cytidine deaminase. Courtesy of Lennart Randau and Dieter Söll.
Structure of Methanopyrus kandleri’s cytidine deaminase. Courtesy of Lennart Randau and Dieter Söll.
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Making its home in boiling thermal vents under the sea, the single-celled Methanopyrus kandleri harbors a genetic mutation that scientists believe should be lethal. The mutation is found in the genes of 30 transfer RNAs, molecules that help assemble proteins in the cell. A team led by biochemist Dieter Söll of Yale University discovered that an editing enzyme, cytidine deaminase, corrects the mutation in the transfer RNA molecules, allowing them to function normally. This study highlights the role played by RNA editing in adding diversity to the sequences encoded in the genome and enhancing the survival of an organism.

NIH’s National Institute of Allergy and Infectious Diseases also supported this work.

Full story (Link no longer available)
Söll lab
Article abstract (from the May 1 issue of Science)

How HIV Infects Cells

HIV particle. Courtesy of NIAID.
HIV particle. Courtesy of NIAID.
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(JPEG, 173 KB)

New research provides a vivid look at how HIV infects cells. Scientists had thought that viruses like HIV that are encased in an “envelope” fused on contact with the membrane wrappers of host cells before emptying their contents into the cell. Virologist Gregory Melikyan of the University of Maryland School of Medicine watched time-lapse videos of HIV-treated cells and noticed something different: The virus slips through the cell’s outer membrane and then fuses with small compartments inside the cell called endosomes, where the virus releases its infectious contents. The findings suggest that the endosome may offer a promising target for designing anti-HIV drugs.

NIH’s National Institute of Allergy and Infectious Diseases also supported this work.

Full story
Melikyan profile
Article abstract (from the May 1 issue of Cell)