Investigation into the relationships between molecular chaperones, mitochondrial antioxidant enzymes, and endothermic vertebrate longevity
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The maximum lifespan (MLSP) of endothermic vertebrates can range from as little as a year to over two centuries, yet the underlying phenotype of aging is very similar amongst this group of organisms. One organelle that may be important in the phenotype of aging is the mitochondrion. When damaged, this organelle is thought to contribute to many of the neurodegenerative diseases of aging. For this thesis, mitochondria from brain tissues of 7 mammalian and 2 avian species were isolated to assess whether the antioxidant glutathione system and major molecular chaperone, HSP60, is correlated to species MLSP. Furthermore, HSP60, and the major endoplasmic reticulum chaperone, GRP78, were measured under basal conditions, and following the introduction of an oxidative stress (hydrogen peroxide) in cultured mammalian myoblasts from 10 different species. My results indicate that the enzymes involved in the glutathione defense system are not correlated to species MLSP in brain mitochondria; however HSP60 levels are indeed higher in the longer-lived species. HSP60 levels are also higher at the basal level in cultured mammalian myoblasts and after 1 hour of hydrogen peroxide exposure. GRP78 induction is not correlated to species MLSP at the basal level or following hydrogen peroxide exposure. Therefore, these results suggest that HSP60 is a correlate of longevity in endothermic vertebrate species, but neither the glutathione antioxidant defense system, nor GRP78, correlates to species longevity.