Effects of Catalase Over-expression on Aging :: Biology Age

Introduction What exactly causes the infirmities of old age? According to the free-radical theory of aging, oxidative damage caused by ROS (reactive oxygen species) is the main culprit. This paper focuses on a study that partly supports this theory by showing that murine life span can be extended by an overexpression of human catalase in mitochondria. The specific paper that this is based on is Extension of Murine Life Span by Overexpression of Catalase Targeted to Mitochondria by Samuel E. Schriner et al. Another paper that was used in the construction of this paper is The Anti-Aging Sweepstakes: Catalase Runs for the ROSes by Richard A. Miller. These scientific papers are summaries of the experiments carried out by Schriner and his group dealing with the topic of catalase-overexpression and its effect on murine lifespan. However, it is important to remember that this is a topic still under much debate. Though these experiments do not provide us with a definat cureall for aging, it is believed by many that the data aquired from them point us to one of the major culprits of aging and age related diseases, ROS's. Why the fuss over R.O.S.? Attempts to prolong longevity have been a major endeavor in science and several hypotheses have been proposed about the major causes. Scientists have focused on the role of reactive oxygen species in longevity through investigations using mice models. Reactive oxygen species’ role in aging processes is also known as the free radical theory of aging. Scientists have found that reactive oxygen species attack molecules of biological systems and are the main cause for the functional decline of organ systems that lead to eventual death. Various experiments were conducted to investigate the role of reaction oxygen species using transgenic mouse models. Specifically, the purpose of these experiments are to determine if minimizing the level of ROS (reactive oxygen species) in certain organelles in mice have any effect on the overall health and lifespan of the mouse. The hypothesis was tested by amplifying a certain gene in mouse DNA that expresses catalase, an enzyme that breaks down the ROS’s. However, prior to beginning the experiments, transgenic mice are necessary for the experimentation. Development of a Transgenic Mouse A transgenic mouse is a mouse that has had a specific gene, in this case the human catalase gene, inserted into its genome.