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These stories describe NIGMS-funded medical research projects. Although only the lead scientists are named, they work together in teams to do this research.

Does Cholesterol Play a Role in Alzheimer's?

Cholesterol might contribute to the development of Alzheimer's disease.

Cholesterol might contribute to the development of Alzheimer's disease

Scientists have long known that cholesterol plays a number of roles—both good and bad—in the body. Now, they suspect it might also contribute to the development of Alzheimer's disease.

To visualize how this might happen, a team of researchers determined the structure of an Alzheimer's-related protein known as APP. To study the protein under normal conditions, the scientists placed it into laboratory-made membranes, which mimic its natural environment.

The scientists, led by Charles Sanders at Vanderbilt University Medical Center in Nashville, Tennessee, showed that APP can hook up with cholesterol in the artificial membranes. Based on other studies, the researchers believe that cholesterol then drives APP into specialized membrane areas known as lipid rafts. There, enzymes hack off pieces of APP, transforming it into a substance called amyloid beta, which accumulates in the brains of those with Alzheimer's.

If this process promotes the disease, as the scientists believe, a drug that prevents APP from connecting to cholesterol might forestall Alzheimer's, a condition that affects up to 5 million people in the United States.
—Alisa Zapp Machalek

How Bacteria Defend Themselves Against Fluoride

Mouth wash

Mouth wash

For decades, people have prevented tooth decay using fluoride, which is found naturally in the environment and added to toothpaste, mouthwash and public water supplies. Fluoride works by strengthening tooth enamel and attacking the bacteria that cause cavities.

But scientists have recently discovered that many bacteria—including those that decay teeth—can defend themselves against fluoride.

A research team led by Ronald Breaker of Yale University in New Haven, Connecticut, found that bacteria use a bit of RNA called a riboswitch to sense and respond to high levels of fluoride. When fluoride attaches to it, the riboswitch activates specific genes that appear to encode proteins called fluoride transporters. The researchers suspect that bacteria use these transporters to rid themselves of fluoride, avoiding its effects.

To parry this bacterial defense system, scientists could try to block the fluoride transporters or disable the fluoride riboswitch. Either way, the goal would be to stop bacteria from escaping a fluoride build-up.
—Amber Dance

Other Spotlights

Bread mold. Credit: Namboori B. Raju, Stanford UniversityFive Foul Things That Are Also Good for You
Usually, we think of mold, feces, nitric oxide, hydrogen sulfide and rat poison as rank, toxic or both. But scientists are learning more about the helpful roles these substances can play.

The 46 human chromosomes are shown in blue, with the telomeres appearing as white pinpoints. The DNA has already been copied, so each chromosome is actually made up of two identical lengths of DNA, each with its own two telomeres. Courtesy of Hesed Padilla-Nash and Thomas Ried, National Institutes of HealthChromosomal Caps in Sickness and in Health
Every cell in your body has a clock called a telomere that ticks down the number of times it can safely divide. If scientists could make drugs to control telomeres, they could perhaps treat diseases of aging as well as cancer.

This cell is undergoing apoptosis, as indicated by the presence of caspase-3 (green), a key tool in the cell's destruction. Credit: Hermann Steller, Rockefeller UniversityCellular Stress Relievers
Find out how cells respond to rising temperatures, toxins, infections, resource shortages and other stressors.

Cilia. Credit: Juliette Azimzadeh, University of California, San Francisco Cilia: Biology's Brooms
Learning more about basic cilia biology is leading to new insights into how problems with cilia cause diseases.

This page last reviewed on September 28, 2012