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Role of reactive oxygen species on animal lifespans

By Tim Sandle     Feb 21, 2015 in Science
Reactive oxygen species (ROS) are chemically reactive molecules containing oxygen. There is an on-going debate to the extent that such chemicals are harmful to animals, including people. This is tied in with the debate around antioxidants.
Reactive Oxygen Species (ROS) have long been known to be a component of the killing response of immune cells to microbial invasion. ROS is a phrase used to describe a number of reactive molecules and free radicals derived from molecular oxygen. Detoxification of reactive oxygen species is paramount to the survival of all life forms. There are also reports that suggest high levels of ROS in the body contribute to ageing (and this has led to a branch of medicine which is looking at whether reducing ROS in the human body can help to extent lifespan).
A new study has shown that the risks are slightly more complex than previously thought. Reactive oxygen species have opposing effects on roundworm longevity depending on whether these molecules are in the mitochondria or the cytoplasm.
Scientists previously found evidence that the effects of ROS in mitochondria can be life span-extending or life span-shrinking, depending on ROS levels. Now, researchers show ROS can also act in opposing ways depending on cellular location. In particular, upping ROS quantities in mitochondria of the roundworm Caenorhabditis elegans actually increased the roundworms’ life spans. However, in the cytoplasm this had the opposite effect.
Researchers looked at the effect of ROS in different cellular compartments by selectively eliminating a C. elegans antioxidant gene in either mitochondria or cytoplasm, thereby boosting ROS levels.
In a research note, the lead scientist, Jeremy Van Raamsdonk of the Van Andel Research Institute’s Laboratory of Aging and Neurodegenerative Disease in Grand Rapids, Michigan, said: “ROS are neither good nor bad. They have functional roles in the cell and it appears that it is crucial to have the right levels of ROS in the right location. This means that treatments with antioxidants may need to be targeted to maximize beneficial effects and minimize possible detrimental effects.”
The findings have been published in the journal PLOS Genetics. The paper is titled “Mitochondrial and Cytoplasmic ROS Have Opposing Effects on Lifespan.”
More about reactive oxygen, oxidation, oxidants, Antioxidants, Lifespan
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