In This Issue... November 17, 2010

High res. image (JPG, 51KB)

Cool Image: Triggering Cell Death

Hermann Steller • Rockefeller University

What look like yellow-green flames show a mitochondrion (blue) in its death throes. Its red-soaked neighbors are already dead. The image comes from research on programmed cell death, or apoptosis, revealing that two proteins, Reaper and Hid (green), join together and travel to mitochondria, the cell's power plants. There, they trigger the release of cytochrome c (red), which in turn activates a fatal chain reaction. The yellow areas show the chromatic mix of the Reaper-Hid complex and cytochrome c. Read more...

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Waking a Dormant Virus

Kazuko Nishikura • The Wistar Institute

People infected with Epstein-Barr virus (EBV) can harbor the pathogen inside their cells for years after the illness. The dormant virus is a major barrier to clearing the infection, which can resurge to trigger diseases like cancer. Scientists have now shown that EBV keeps a low profile during this phase by deploying microRNAs, snippets of RNA that silence its genes. By targeting EBV's microRNAs, we may be able to arouse the virus, exposing it to the immune system and eliminating it from the body. Read more...

NIH's National Cancer Institute and National Heart, Lung, and Blood Institute also supported this work.

Caption: Two Epstein-Barr virus particles (top left; bottom right). Credit: Liza Gross. High res. image (JPG, 127KB)

Cellular Wakes and Eddies Slow Down Molecules

Jeffrey Skolnick • Georgia Institute of Technology

Like a busy shipping port, cells are crowded with different molecules that maneuver around each other to reach their destination. So what physical forces have the most impact on these molecular movements? A new simulation suggests that it's the wakes and eddies the molecules generate as they move through the cellular water. The results come from a small-scale study—15 types of molecules packed at realistic concentrations inside a model E. coli cell—but they set the stage for whole-cell simulations to study everything from cell division to drug side effects. Read more...

Caption: Proteins, RNA, DNA and other molecules crowd cells. Credit: Jeffrey Skolnick. High res. image (JPG, 63KB)

For Prions, Size Does Matter

Tricia Serio • Brown University

Researchers have thought that how fast mad cow disease and its human variant, Creutzfeldt-Jakob disease, spread in the body depends mainly on the number of misfolded proteins called prions that accumulate in cells. A new study based on the mathematical modeling of prion movement between yeast cells suggests that the size of those prion clumps matters more: Big clumps can't spread from cell to cell. The findings could improve understanding of prion diseases in mammals and help inform future treatment strategies. Read more...

NIH's National Institute on Aging also supported this work.

Caption: Prion clumps tagged fluorescent green in an infected yeast cell. Credit: Serio Lab. High res. image (JPG,27KB )

Improved Method for Making Anti-Cancer Drug

Gregory Stephanopoulos • MIT

A pacific yew tree provides enough ingredient to produce just one dose of the cancer-fighting drug Taxol. Now scientists have found a way to metabolically engineer E. coli to produce mass quantities of taxadiene, the precursor to Taxol. By adding two plant genes to a compound found in E.coli, they discovered that they could use the bacteria to synthesize taxadiene. This finding could make Taxol cheaper and lead to new methods for generating enough material to develop therapeutic variations of the anti-cancer drug. Read more...

Caption: A close-up view of E. coli. High res. image (JPG,52KB)