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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.

In This Issue... February 21, 2013

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Animation showing the changes in the structure of a T7 virus as it infects an E. coli bacterium.

Cool Video: How a Virus Infects

William Margolin • University of Texas Health Science Center at Houston Medical School

A virus can behave like a predator during its search for the ideal host. A new animation shows how it finds and infects a cell. Here, a T7 virus, with its head colored blue and tail colored red, searches for a suitable E. coli bacterium. While what we're about to see is specific to T7, a similar process may allow other viruses to infect cells. The details may offer future targets for drug development. The T7 virus has six ultra-thin fibers, shown here in yellow, that are folded at the base of the head. While roaming the cell, the virus extends a few of these fibers. This action allows the virus to move freely around the cell. The fibers "walk" across the surface of an E. coli until the virus locates an optimal site for infection. As it prepares to infect, all of the virus's fibers bind to the outer membrane of the cell. The virus then undergoes a major structural change as it ejects some of its proteins, represented in green, through the bacterium's cell membrane. This creates a path for the virus's genetic material, shown in purple, to enter and subsequently infect the cell. After the viral DNA has been released, the protein path collapses and the cell's membrane reseals. Animation developed by Bo Hu and Jun Liu, UT Health, and published in Science. Read more. Link to external Web site

This work also was supported by NIH's National Institute of Allergy and Infectious Diseases.

Illustration of a large intestine.

Getting to the Bottom of Intestinal Inflammation and Cancer

Sarah Spiegel • Virginia Commonwealth University

One of the dangers of inflammatory bowel disease (IBD) is the risk of developing intestinal cancers, such as colorectal cancer. Results from a recent study suggest that fingolimod, a drug already approved to treat multiple sclerosis, could decrease or possibly stop the progression of IBD-related cancers. Using a mouse model, researchers showed that increased production of an enzyme causes intestinal cells to produce more molecules that trigger intestinal inflammation and cancer. Giving fingolimod to the mice decreased these activities. The scientists are planning more experiments to understand the link between inflammatory disease and intestinal cancers and to help test the multiple sclerosis drug as a potential new treatment for IBD-related cancers. Read more... Link to external Web site

This work also was supported by NIH's National Cancer Institute; National Institute of Allergy and Infectious Diseases; National Heart, Lung, and Blood Institute; National Human Genome Research Institute; and National Institute of Neurological Disorders and Stroke.

Caption: Inflammatory bowel disease (IBD) refers to diseases that cause inflammation in the small intestine and colon. Credit: National Institute of Diabetes and Digestive and Kidney Diseases, NIH. High res. image (JPG, 91KB)
An artist's rendition of nerve cells monitoring the surface of the skin. Credit: Tim Phelps, Johns Hopkins University.

Explaining the Itch Factor

Xinzhong Dong • Johns Hopkins University School of Medicine

Eating hot peppers sets your mouth on fire, while getting stung makes you scratch. A group of sensory nerve cells signal such pain and itch. However, scientists have wondered whether these nerves actually communicate both sensations to the brain. A series of experiments using mice confirmed that a subset of these cells does send pain and itch signals but that mouse brains interpreted both as itch. So when mice with these cells were exposed to the fiery substance in hot peppers, they scratched their cheeks, instead of pawing away the pain. If confirmed in humans, the findings may help lead to treatments for chronic itch, including itch caused by medications. Read more... Link to external Web site

This work also was supported by NIH's National Institute of Neurological Disorders and Stroke.

Caption: An artist's rendition of nerve cells monitoring the surface of the skin where they may encounter pain stimulants like capsaicin, found in hot peppers, and itch stimulants like histamine. Credit: Tim Phelps, Johns Hopkins University.
Structure of the bacterium that causes MRSA infections. Credit: Wei Zhu and Eric Oldfield, University of Illinois at Urbana-Champaign.

New Compound Treats MRSA in Mice

Eric Oldfield • University of Illinois at Urbana-Champaign
J. Andrew McCammon • University of California, San Diego

MRSA, an antibiotic-resistant staph infection, can be deadly, especially to people with weakened immune systems. Researchers have discovered a new anti-MRSA compound and tested it in mice. All 20 infected mice that received the compound survived. The compound also boosted the power of methicillin against the bacterium, potentially reinstating the antibiotic as an effective drug against MRSA infections in people. The work could lead to new treatments for infections caused by MRSA, including combination therapies that involve methicillin, as well as completely new antibiotics. Read more... Link to external Web site

This work also was supported by NIH's National Institute of Allergy and Infectious Diseases, National Cancer Institute and Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Caption: A newly discovered compound (green and royal blue sticks) appears to block the action of a key enzyme (light blue ribbons) in the bacterium that causes MRSA infections. Credit: Wei Zhu and Eric Oldfield, University of Illinois at Urbana-Champaign. High res. image (JPG, 179KB)
Bottle labeled Folic Acid

Enzyme Plays a Role in Folic Acid's Effectiveness

Dean Appling • University of Texas at Austin

Scientists recently set out to discover how birth defects occur in the embryos of some women even though they supplement their diets with folic acid. They found that mice lacking a gene for a folic acid enzyme called Mthfd1l were unable to produce formate, which is essential for normal embryo development. The work also revealed that one way folic acid reduces birth defects is by contributing to the production of formate in mitochondria. Future studies could aid the design of folic acid substitutes for women lacking Mthfd1l. Read more... Link to external Web site

Caption: Folic acid can help prevent neural tube birth defects in embryos.

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This page last reviewed on February 21, 2013