Biomedical Beat - A monthly digest of research news from NIGMS

IN THIS ISSUE . . .
August 18, 2010

Check out the Biomedical Beat Cool Image Gallery.

Got research news to share? E-mail us at info@nigms.nih.gov.

To change your subscription options or unsubscribe, visit https://public.govdelivery.com/accounts/USNIGMS/subscriber/new?topic_id=USNIGMS_3.

Biomedical Beat RSS FeedSubscribe to the RSS version of Biomedical Beat by selecting this XML link and following your news reader's instructions for adding a feed.

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, Twitter or Facebook. To check out free NIGMS publications, go to the order form.

Cool Image: Cellular Loner

Courtesy of cell biologist Mary Anne Alliegro, Marine Biological Laboratory.

The nucleolinus is a cellular compartment that has been a lonely bystander in scientific endeavors. Although it’s found in a range of species, its function has been mysterious—mainly because the structure is hard to visualize. Now, a study shows that the nucleolinus is crucial for cell division. When researchers zapped the structure with a laser, an egg cell didn’t complete division. When the oocyte was fertilized after laser microsurgery (bottom right), the resulting zygote didn’t form vital cell division structures (blue and yellow). Perhaps now the nucleolinus has earned its rightful place inside the cell and in scientific research. Courtesy of cell biologist Mary Anne Alliegro, Marine Biological Laboratory.

Full story Link to external Web site
Article abstract (from the August 3 issue of PNAS)

More than Meets the Eye

Eye diagram. Courtesy of NIH’s National Eye Institute.
Eye diagram. Courtesy of NIH’s National Eye Institute.
High res. image
(JPG, 940 KB)

Special cells in the eye use light to set our circadian rhythms, the 24-hour cycles that dictate when we sleep and when we’re awake. It turns out that these cells also play other roles in vision, according to a new study led by neurobiologist Samer Hattar of Johns Hopkins University. The team found that the cells, at least in mice, have more widespread targets in the brain than previously thought and that they enabled mice lacking other light-sensing cells to discern spatial information about their surroundings. These findings challenge traditional views about vision and offer new hope for correcting blindness.

NIH’s National Eye Institute also supported this work.

Full story Link to external Web site
Hattar profile Link to external Web site
Article abstract (from the July issue of Neuron)

Quick Fix for Sunburn

Plants and most animals have a protein that helps protect them from DNA-damaging UV light.
Plants and most animals have a protein that helps protect them from DNA-damaging UV light.

Ultraviolet (UV) rays cause not just sunburns, but also genetic mutations, cancer and cell death. In plants and most animals (except placental mammals, like humans), the photolyase protein repairs the damage. Scientists, though, know little about how the process works. To find out, biophysicist Dongping Zhong at Ohio State University exposed DNA to UV light and then took ultrafast laser “snapshots” to catch photolyase in action. The protein complex delivered an electron and proton to the damaged DNA, reversing the effects in billionths of a second. Once done, the electron and proton returned to the photolyase complex. This information could lead to future remedies for healing UV damage.

Full story Link to external Web site
Zhong lab Link to external Web site
Article abstract (published online July 25 in Nature)

Enhancing Development

Fly embryos without gene enhancers lose their hair at extreme temperatures. Courtesy of Nicolás Frankel and David Stern.
Fly embryos without gene enhancers lose their hair at extreme temperatures. Courtesy of Nicolás Frankel and David Stern.
High res. image
(JPG, 44KB)

Individual genes often have multiple enhancers, regions of DNA that increase gene expression. Scientists suspected that some enhancers act as backups so that desired traits are expressed, even amidst unfavorable environmental and genetic conditions. A team led by Princeton University evolutionary biologist David Stern has found support for this idea. When the researchers removed two apparently redundant enhancers from a gene coding for fruit fly larvae hair development, they noticed that, at intermediate temperatures, the hairs formed correctly. But, at extreme temperatures, embryos without the enhancers lost much of their hair as larvae. The findings confirm that such enhancers make development resilient in the face of challenging conditions.

Full story Link to external Web site
Stern lab Link to external Web site
Article abstract (from the July 22 issue of Nature)



Modeling the Origin of Organisms

Model may help explain division of labor in social insects.
Model may help explain division of labor in social insects.
High res. image
(JPG, 36KB)

A multicellular organism consists of specialized cells with distinct functions that collectively ensure survival and reproductive success. Sergey Gavrilets, a theoretical biologist at the University of Tennessee, Knoxville, has developed a simple and biologically realistic model that shows how cells can become dedicated to such important functions. He found that the division of roles and responsibilities could occur relatively rapidly, depending on the mutation rate, the number of cells and other factors. The theoretical results may also explain the division of labor in social insects, the inception of organs and, more generally, the origin of biological complexity.

Full story
Gavrilets lab Link to external Web site
Article abstract (from the June issue of PLoS Computational Biology)