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Why stress damages our DNA

Researchers at Duke University Medical Centre have discovered a mechanism that could explain why stress causes DNA damage.

“We believe this paper is the first to propose a specific mechanism through which a hallmark of chronic stress, elevated adrenaline, could eventually cause DNA damage that is detectable,” said senior author Robert J. Lefkowitz, James B. Duke Professor of Medicine and Biochemistry and a Howard Hughes Medical Institute (HHMI) investigator at Duke University Medical Centre.

“This could give us a plausible explanation of how chronic stress may lead to a variety of human conditions and disorders, which range from merely cosmetic, like greying hair, to life-threatening disorders like malignancies,” Lefkowitz said.

P53 is a tumour suppressor protein and is considered a “guardian of the genome” — one that prevents genomic abnormalities.

“The study showed that chronic stress leads to prolonged lowering of p53 levels,” said Makoto Hara, a postdoctoral fellow in the Lefkowitz laboratory. “We hypothesize that this is the reason for the chromosomal irregularities we found in chronically stressed mice.”

Saltwater to make microbial life on Mars possible?
Scientists in the United States are set to create Mars conditions in lab chambers to see if microbial life exists in droplets of saltwater on the red planet.

A new million-dollar NASA project led by the University of Michigan will begin three years after beads of liquid brine were first photographed on one of the Mars Phoenix lander's legs.

The Phoenix photos are believed to be the first pictures of liquid water outside the Earth.
“On Earth, everywhere there's liquid water, there is microbial life,” said Nilton Renno, a professor in the Department of Atmospheric, Oceanic and Space Sciences who is the principal investigator.

Once scientists create Mars conditions of atmospheric pressures and temperatures in the lab, they will study how and when brines form.

Their colleagues overseas will seed similar chambers with salt-loving “extremophile” microorganisms from deep in Antarctic lakes and the Gulf of Mexico. The will observe whether these organisms survive, grow and reproduce in brines just below the surface of the soil. All known forms of life need liquid water to live. But microbes don't need much. A droplet or a thin film could suffice, researchers say.
 
Scientists manipulate sugar to improve efficiency of drugs
Sugars attached to drugs can enhance, change or neutralize their effects, a US scientist has said.

Jon Thorson, a professor of pharmaceutical sciences at the University of Wisconsin-Madison School of Pharmacy, an expert in the attachment and function of these sugars, said that understanding and controlling them has major potential for improving drugs, but that researchers have been stymied because many novel sugars are difficult to create and manipulate.

“The chemistry of these sugars is difficult, so we have been working on methods to make it more user friendly,” he said.  Now, Thorson, graduate student Richard Gantt and postdoctoral fellow Pauline Peltier-Pain have described a simple process to separate the sugars from a carrier molecule, then attach them to a drug or other chemical.

 The process also causes a colour change only among those molecules that have accepted the sugar. The change in colour should support a screening system that would easily select out transformed molecules for further testing.

The new molecules included 11 variants of vancomycin, a powerful antibiotic, each distinguished by the nature and number of attached sugars.

In a single test tube, the new technique is able to detach the sugar from its carrier and reattach it to the biological target molecule, Thorson says.

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