p66Shc Aging Protein in Control of Fibroblasts Cell Fate

Reactive oxygen species (ROS) are wieldy accepted as one of the main factors of the aging process. These highly reactive compounds modify nucleic acids, proteins and lipids and affect the functionality of mitochondria in the first case and ultimately of the cell. Any agent or genetic modification that affects ROS production and detoxification can be expected to influence longevity. On the other hand, genetic manipulations leading to increased longevity can be expected to involve cellular changes that affect ROS metabolism. The 66-kDa isoform of the growth factor adaptor Shc (p66Shc) has been recognized as a relevant factor to the oxygen radical theory of aging. The most recent data indicate that p66Shc protein regulates life span in mammals and its phosphorylation on serine 36 is important for the initiation of cell death upon oxidative stress. Moreover, there is strong evidence that apart from aging, p66Shc may be implicated in many oxidative stress-associated pathologies, such as diabetes, mitochondrial and neurodegenerative disorders and tumorigenesis. This article summarizes recent knowledge about the role of p66Shc in aging and senescence and how this protein can influence ROS production and detoxification, focusing on studies performed on skin and skin fibroblasts

Nitrate Reductase Activity in Tall Fescue

An in vitro assay for tall fescue leaf nitrate reductase activity (NRA) was established that required either O.5 % casein or polyvinylpyrrolidone in the extraction medium for maximal activity. Leaf NRA was proportional to light intensity and fertility levels. Mature tissue and high temperature decreased NRA. NRA showed significant genetic variability in broadly based genotypes and genotypes selected for photosynthetic rates and forage yields. However, progeny of the latter did not show significant genetic variability. High coefficients of variation (30-50%) among the heterogeneous progeny may have masked true genetic differences. No significant correlations were found between NRA and photosynthesis or yield in the parents