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Cross-Bridge Mechanisms Of Skeletal Muscle Fatigue: Effects Of Hydrogen Ion, Inorganic Phosphate, And Age, Cassandra Rae Nelson Jul 2014

Cross-Bridge Mechanisms Of Skeletal Muscle Fatigue: Effects Of Hydrogen Ion, Inorganic Phosphate, And Age, Cassandra Rae Nelson

Dissertations (1934 -)

Intense muscle contraction induces high rates of glycolysis and ATP hydrolysis with resulting increases in inorganic phosphate (Pi) and H+, factors thought to induce fatigue by interfering with steps in the cross-bridge cycle. Force inhibition is less at physiological temperatures; thus the role of low pH in fatigue has been questioned. Effects of pH 6.2 and collective effects with 30 mM Pi on the pCa-force relationship were assessed in skinned fast and slow rat skeletal muscle fibers at low (15°C) and near-physiological temperatures (30°C). At Ca2+ levels characteristic of fatigue, low pH significantly depressed force at both temperatures and in …


Understanding How Honey Bee Flight And Senescence Are Connected Through Oxidative Stress., Joseph Margotta May 2014

Understanding How Honey Bee Flight And Senescence Are Connected Through Oxidative Stress., Joseph Margotta

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this dissertation was to exploit the tractability of the honey bee (Apis mellifera) to understand how the physiological and cellular mechanisms that determine the onset and duration of senescence are shaped by behavioral development and behavioral intensity. These data reveal how behavior can damage cells and consequently limit lifespan. The honey bee represents the ideal model to address these factors because age, behavior, functional senescence, and lifespan are easily manipulated independently of each other while in its natural environment. I determined if there was a cause-effect relationship between honey bee flight and oxidative stress by comparing damage …


Circadian Regulation Of Mtor Signaling Via Bmal1 Dependent Mechanism, Rohini Vishal Khapre Jan 2014

Circadian Regulation Of Mtor Signaling Via Bmal1 Dependent Mechanism, Rohini Vishal Khapre

ETD Archive

Understanding mechanisms of aging is important for the treatment and prevention of age-associated pathologies. However, these mechanisms are not well understood. Recently we have demonstrated that the circadian clock (an internal time keeping system) regulates longevity in mammals, but the molecular mechanisms are not known. The aim of our current study is to investigate a possible interconnection between the circadian clock and mTORC1 (mammalian target of Rapamycin) signaling pathway. mTORC1 pathway is a nutrient response pathway involved in many cellular processes many recent studies indicate a role of mTORC1 pathway in aging. Here we demonstrate that circadian system regulates mTORC1 …


An Analysis Of The Effect Of Ss-Hydroxy-Ss-Methylbutyrate On The Flight Ability And Lifespan Of Drosophila Melanogaster, Alexandra Elizabeth Beattie Jan 2014

An Analysis Of The Effect Of Ss-Hydroxy-Ss-Methylbutyrate On The Flight Ability And Lifespan Of Drosophila Melanogaster, Alexandra Elizabeth Beattie

Graduate College Dissertations and Theses

As muscle function deteriorates with age, the discovery of new ways to enhance the quality of human life by stunting inevitable aging processes, such as sarcopenia, is a subject of great interest to aging populations, to health care professionals and to nutritional companies. β-hydroxy-β-methylbutyrate (HMB) enhances muscle strength in humans and attenuates disease-induced and disuse-dependent atrophy in rodents. We investigated the feasibility of utilizing Drosophila as a model organism to study the biological effects of HMB in aging muscle. Using flight ability as an index of muscle function and monitoring the lifespan of flies, we found that normal food supplemented …