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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... January 19, 2012

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Caulobacter crescentus

Cool Image: Bacterial Glue

Yves Brun and Clay Fuqua • Indiana University

The tiny water bacterium Caulobacter crescentus secretes a sugary substance so sticky that just a tiny bit could hold several cars together. First, it attaches to a surface at the end of its cell body, which has a propeller-like flagellum. On contact, the flagellum stops moving with help from nearby cable-like structures called pili. This arrest stimulates production of the sugary adhesive, which then is released at the attachment site and immediately binds the cell to the surface. Since binding helps some bacteria form slimy residues and hard-to-treat infections, knowing how this occurs could help us better understand how to treat and prevent such outcomes. Read more... Link to external Website
Network representation of HIV/human protein interactions. Credit: Nevan Krogan

HIV's Pathogenic Landscape

Nevan Krogan • University of California, San Francisco

While HIV has only a handful of proteins of its own, a new study shows that the virus makes the most of its small repertoire. Researchers used a comprehensive approach to uncover nearly 500 interactions between HIV and human proteins. The study has produced one of the most detailed surveys to date of how HIV interacts with human cells. Most of these interactions were previously unknown, opening up a vast new territory of potential drug targets for treating people infected with HIV. Read more... Link to external Website

NIH's National Institute of Allergy and Infectious Diseases and National Center for Research Resources also supported this work.

Caption: Network representation of HIV/human protein interactions. Credit: Nevan Krogan High res. image (JPG, 210KB)
Hydrogen sulfide molecule

Malodorous Molecule an Accessory in Cellular Suicide

Nicholas K. Tonks • Cold Spring Harbor Laboratory

A factory's assembly line goes haywire, and products in various stages of completion spill out until the line shuts down. When cells, most of which are constantly making proteins, face this challenge, they have two choices: slow down production or, if the situation is bad enough, commit suicide. Cells decide using a tightly controlled process that involves the nasty-smelling molecule hydrogen sulfide (H2S). Better known as an explosive, highly toxic gas that reeks like rotten eggs, H2S might help researchers understand diseases linked to excess cellular suicide like Alzheimer's and Parkinson's. Read more... Link to external Website

Caption: Hydrogen sulfide, whose structure looks nearly identical to water, can cause irritated eyes, headache and, at high levels, death. It's also an important signaling molecule in our bodies.

Riboswitch Prevents Fluoride from Fighting Bacteria

Ronald Breaker • Yale University

The fluoride in toothpaste and tap water helps protect teeth from cavity-causing bacteria. Scientists recently learned about the events that happen when bacteria come into contact with fluoride. By mixing bacterial RNA with a variety of chemicals in a test tube, scientists discovered a group of riboswitches (sections of RNA) in bacteria that bind to fluoride. When this occurs, the fluoride-sensing riboswitch activates genes coding for ion channels that pump fluoride back out of the cell. The finding may help scientists increase the potency of fluoride and make it more toxic to bacteria. Read more... Link to external Website

Caption: Riboswitches help bacteria survive when exposed to fluoride.
mRNA molecules (red)

mRNA: Marked for Destruction

Robert Singer • Albert Einstein College of Medicine

Many of the proteins that control cell division appear for a single step of the process and then vanish until the next round of division. A team of researchers working in yeast has now discovered how certain transient proteins are marked for destruction. As soon as they're made, the messenger RNA molecules that serve as the proteins' blueprints get tagged with a special protein. These tagged mRNAs later degrade in response to a cellular signal, triggering the disappearance of the proteins they encode. This work offers new insights into how cells control division and may lead to new ways to combat the runaway cell division that characterizes cancer. Read more... Link to external Website

Caption: Some mRNA molecules (red) are marked for destruction from the moment they are born. Credit: Robert Singer High res. image (JPG, 26KB)

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This page last reviewed on January 19, 2011