缅北强奸

When it comes to slowing aging, the much ballyhooed properties of antioxidants may have some surprise wrinkles. For more than 40 years, prevailing wisdom has linked aging to cellular oxidative stress. This theory postulates that a build-up of reactive oxygen species, or ROS, molecules overwhelms a cell鈥檚 ability to repair damage鈥攃ausing the cell to age. The theory spawned an industry of alternative antioxidant therapies (such as megadosing on Vitamin E) and gladdened fans of antioxidant-rich tipples like red wine. It just might not be, well, true.

In a study published in the February 2009 issue of the journal PLoS Genetics, 缅北强奸 professor Siegfried Hekimi, the Strathcona Chair of Zoology and Robert Archibald & Catherine Louise Campbell Chair in Developmental Biology, and postdoctoral fellow Jeremy Van Raamsdonk show that oxidative stress may just as easily be the result鈥攏ot the cause鈥攐f aging. The researchers genetically modified Caenorhabditis elegans worms so they were progressively less able to produce a group of proteins called superoxide dismutases (SOD), which detoxify one of the main ROS molecules. Previous studies seemed to show that decreased SOD production shortened an organism鈥檚 lifespan, but the researchers found the opposite to be true: Even though oxidative stress was elevated, none of the mutant worms showed decreased lifespan鈥攁nd some even lived longer than their unmodified kin.