Biomedical Beat - A monthly digest of research news from NIGMS

IN THIS ISSUE . . .
December 19, 2007

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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. To read additional news items, visit NIGMS News. To check out free NIGMS publications, go to the order form.

Cool Image: Protein Wreath

Structure formed by a plant pathogen protein. Courtesy of Ken Schwinn and Sonia Espejon-Reynes, New York SGX Research Center for Structural Genomics.

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The wreath-like structure formed by a plant pathogen protein inspired a team of structural biologists to dress it up for the holidays. The structure, whose function is unknown, is the first to represent a region shared by a family of proteins. It's among more than 2,700 protein structures generated by the Protein Structure Initiative—an international effort to make the shapes of nearly all proteins readily available from their DNA sequences. Courtesy of Ken Schwinn and Sonia Espejon-Reynes, New York SGX Research Center for Structural Genomics.

New York SGX Research Center for Structural Genomics home page
Protein Structure Initiative home page

Cholera's Chemical Line of Communication

Cholera bacteria accumulate in human intestines until they’ve overpopulated their surroundings and expel themselves from their hosts by triggering severe vomiting and diarrhea. When the bacteria decide to leave and how they broadcast the "abandon ship" command has remained a mystery. Until now. Molecular biologist Bonnie Bassler and colleagues at Princeton University have identified and manufactured the chemical signal, CAI-1, that tells cholera to evacuate the host. The research team’s next step: to see if the molecule cures cholera in laboratory mice. The work could point to new ways of treating cholera and other diseases caused by bacteria that use similar communication strategies.

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

Full story
Bassler lab home page
Article abstract (from the November 14 online issue of Nature)
Bugging the Bugs

DNA Unwinds at Night

Blue-green algae containing a protein that fluoresces in response to the microbe’s biological clock. Courtesy of the Johnson lab.
Blue-green algae containing a protein that fluoresces in response to the microbe’s biological clock. Courtesy of the Johnson lab.
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When we go to sleep at night, our bodies have a chance to unwind. Our DNA may be doing the same thing. Vanderbilt University biologist Carl Johnson has discovered that the DNA of tiny blue-green algae—a simple organism with a biological clock—is coiled tightly during the day and more relaxed at night. This pattern allows certain genes to change their activity in light or darkness, essentially helping the organism tell time and suggesting why biological clocks influence so many biochemical processes. Although more research needs to be done, Johnson speculates that human DNA may also wind and unwind according to time of day.

Full story
Johnson lab home page
Article abstract (from the November 20 issue of PNAS)

Software to Track Infectious Disease Outbreaks

Health authorities at the site of an infectious disease outbreak have a new tool to help them track cases and speed the implementation of interventions. By downloading a free software program called TranStat, they can systematically enter and store disease-related data about infected individuals and their close contacts. The program, developed by Ira Longini of the Fred Hutchinson Cancer Research Center and Diane Wagener of RTI International, also calculates the probability of person-to-person transmission. Such information could help health officials develop and swiftly implement strategies that thwart further spread while they conduct additional studies.

Full story
TranStat home page
Longini home page
Wagener home page

Skin Cells Yield Embryonic Stem Cell Stand-Ins

Scientists have produced what appear to be embryonic stem cells (center) from human skin cells (periphery). Courtesy of Junying Yu.
Scientists have produced what appear to be embryonic stem cells (center) from human skin cells (periphery). Courtesy of Junying Yu.
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Hailed as a scientific breakthrough, University of Wisconsin-Madison cell biologist James Thomson has used human skin cells to create ones that appear to be indistinguishable from embryonic stem cells. Thomson reset the skin cells to the embryonic state by supplying them with four genes, giving them the potential to become any of the 220 cell types in the body. The new technique is expected to bring stem cells within easier reach of more scientists, providing them with better models for studying many human diseases and possibly speeding the advent of cell-based therapies for conditions such as diabetes and arthritis.

This work also was supported by NIH's National Center for Research Resources.

Full story
Thomson home page
Article abstract (from the November 20 issue of Science)