Biomedical Beat - A monthly digest of research news from NIGMS

IN THIS ISSUE . . .
April 18, 2006

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The National Institute of General Medical Sciences (NIGMS), one of the National Institutes of Health, supports all research featured in this digest. Although only the lead scientists are named, coworkers and other collaborators also contributed to the findings. To read additional news items, visit NIGMS News.

Cool Image: Tiny Points of Light

Courtesy of chemist Sandra Rosenthal and postdoctoral fellow James McBride, both at Vanderbilt University; and Stephen Pennycook, a physicist and electron microscopist at Oak Ridge National Laboratory.
High res. image (588 KB JPEG)

This fingertip-shaped group of lights is a microscopic crystal called a quantum dot. The entire dot is less than 20 nanometers across—or about 10,000 times thinner than a sheet of paper. Under ultraviolet light, a quantum dot radiates a brilliant color depending on its size. Biomedical researchers harness these dots to label and track individual molecules in living cells. They expect the dots will soon be used for speedy disease diagnosis, DNA testing, screening for illegal drugs, and the detection of biological weapons. Courtesy of chemist Sandra Rosenthal and postdoctoral fellow James McBride, both at Vanderbilt University; and Stephen Pennycook, a physicist and electron microscopist at Oak Ridge National Laboratory. Funding was provided by a grant to David W. Piston, a biophysicist at Vanderbilt University.

Rosenthal lab home page
Oak Ridge National Lab Group home page
Piston lab home page

Rave Reviews for a New Cell Movie

For scientists, it’s a blockbuster release: the first-ever action movie of a protein factory in living cells. Chemist X. Sunney Xie of Harvard University and his team developed a new way to watch single proteins as they emerge in real time from biological machines called ribosomes. The work is a technical breakthrough and promises a leap in scientists’ understanding of gene expression and other fundamental biological processes.

Full story
Xie lab home page
Article abstracts (from the March 16, 2006, issue of Nature and the March 17, 2006, issue of Science)

Getting Back to Nature

Nisin is an antibiotic that has been used for over 40 years to prevent food-borne infections like botulism and listeriosis. Despite its long use in the food industry as a preservative, nisin has not induced antibiotic resistance like many other drugs. Nisin’s resilience stems from its double punch against microbes. First, it pokes holes in them, draining vital components. It also makes bacteria vulnerable by blocking their ability to make a tough, protective cell wall. Chemist Wilfred van der Donk of the University of Illinois at Urbana-Champaign led a team that figured out how the natural enzyme makes nisin. This information enabled van der Donk to create nisin in a test tube in just a few steps. Mimicking nature’s approach trims time and effort from the 67-step method chemists used up until now to synthesize nisin. The team also identified the structure of the nisin enzyme. This work could point the way to developing other antibiotics not easily outwitted by bacteria.

Full story
Van der Donk lab home page
Article abstract (from the March 10, 2006, issue of Science)

Pin1 Provides New Clues to Alzheimer’s

Structure of the Pin1 enzyme. Courtesy of Lu.
High res. image (185 KB JPEG)
Structure of the Pin1 enzyme. Courtesy of Lu.

Alzheimer’s disease is characterized by the presence of tau protein tangles and amyloid peptide plaques in the brain, but the relationship between these two types of lesions has been unclear. New work led by molecular biologist Kun Ping Lu of the Beth Israel Deaconess Medical Center may provide the missing link. Lu’s group had previously shown that the enzyme Pin1 could help prevent tau protein tangles and protect against nerve damage. In new studies using mice, Lu and his team have uncovered a role for Pin1 in preventing plaque formation as well. The findings suggest that lack of Pin1 could play a key role in Alzheimer’s and that the enzyme could serve as a target for treating the disease.


Full story

Lu lab home page
Article abstract (from the March 23, 2006, issue of Nature)

Computer Model Strategizes Ways to Mitigate U.S. Flu Pandemic

Snapshots of hypothetical spread of a moderately contagious pandemic flu in the United States (top: no intervention; bottom: distribution of vaccine). Color changes from green to red as more people in the area become infected. Courtesy of PNAS.

Snapshots of hypothetical spread of a moderately contagious pandemic flu in the United States (top: no intervention; bottom: distribution of vaccine). Color changes from green to red as more people in the area become infected. Courtesy of PNAS.

If pandemic flu were to emerge in the United States, what interventions might slow its spread and minimize the impact? To explore possible answers, a team of researchers led by biostatistician Ira M. Longini, Jr., of the Fred Hutchinson Cancer Research Center and the University of Washington School of Public Health and Community Medicine developed a computer model that realistically represents the U.S. population. They used the model to simulate the spread of a potential pandemic flu outbreak in the United States to evaluate the effect of intervention strategies. The model indicated that, depending on the contagiousness of the virus, a variety of approaches could reduce the number of cases to less than that of an annual flu season. The project is part of the Models of Infectious Disease Agent Study (MIDAS), a research network funded by NIGMS.

Full story
MIDAS home page
Article abstract (from the April 3 online issue of PNAS)