Testing Direct Effects of Reproduction on Stress and Mortality via Ovariectomy

DESCRIPTION (provided by applicant): This project will examine how ingested nutrients are allocated, and cells are maintained, upon two experimental treatments that extend lifespan in grasshoppers. The experimental manipulations of reducing dietary intake or reducing reproductive output are two of the most common means of extending lifespan in simple animals. The predominant hypothesis (viz., the disposable soma hypothesis) suggests that both reducing dietary intake and reducing reproductive output extend lifespan by shifting allotment of ingested nutrients from reproduction to maintaining the body. This results in improved cellular maintenance of the body and thereby longer life. Despite the prevalence of this nutrient allocation hypothesis, it has been rigorously tested only once;that test lacked a measure of the level of cellular maintenance. Rigorous tracking of ingested nutrients in grasshoppers with reduced reproduction (Aim #1) or reduced diet (Aim #2), and simultaneously measurement of cellular maintenance are proposed. Nutrients will be tracked by feeding grasshoppers diets that have distinct non-radioactive isotopic signatures;if these signatures are seen in body tissues after feeding, it is evidence that these ingested nutrients have been incorporated into the body. Cellular maintenance will be measured by quantifying the activity of anti-oxidant enzymes in body cells. These enzymes remove molecules that cause wear-and-tear damage in cells. The disposable soma hypothesis predicts that either reduced reproduction or reduced diet will increase lifespan, increase allocation of ingested nutrients to the body (at the expense of reproduction), and increase anti-oxidant activity in those same parts of the body. PUBLIC HEALTH RELEVANCE: Understanding the internal mechanisms by which dietary restriction or reduced reproduction extend lifespan in simple animals may lead to development of other treatments to extend the healthy years of people. Slowing the aging process itself could delay the onset of the major killers in our society (e.g., heart disease, cancer) and increase the number of healthy years for people. Last but not least, this grant will have a profound effect on the research environment in biology at the University of North Florida, by increasing the quality and quantity of opportunites for student research in biomedical science.