Life Sciences Commons^™

Stretch Activation During Fatigue Improves Relative Force Production In Fast-Contracting Mouse Skeletal Muscle Fibers, Philip C. Woods

Masters Theses

Stretch activation (F_SA) is the delayed increase in fiber specific tension (force per cross-sectional area) following a rapid stretch and can improve muscle performance during repetitive cyclical contractions. Historically considered minimal in skeletal muscle, our recent work showed the ratio ofstretch- to calcium-activated specific tension (F_SA/F₀) increased from 10 to 40% with greater inorganic phosphate (Pi) levels in soleus muscle fibers (Straight et al., 2019). Given Pi increases with muscle fatigue, we hypothesize that F_SA helps maintain force generation during fatigue. To test this, F_SA, induced by a stretch of 0.5% …

Deciphering The Role Of Mitochondrial Physiology And Thermal Acclimation In Shaping Whole Organismal Performance Of An Invasive Forest Pest, Essa Alrashdi

Masters Theses

Environmental factors such as temperature are substantial determinants of the spongy moth, L. dispar, distribution, reproduction, and growth. Accumulating energy reserves at the larval stage is particularly important to L. dispar, since the larvae metamorphose into a fully-grown, non-feeding adult. As non-feeding adults, the energy balance of the pupae must be adequate, to ensure enough energy reserves for adult dispersal, egg maturation and overall persistence of the species in the region. At this stage, environmental temperature also determines daily metabolic demands, and the overall cost of sustaining ecologically relevant activities. Various hypotheses describing a mismatched growth and metabolic …

Does Epa Cause A Decrease In Inflammation Of Bend.3 Cells Through Ffar4?, Clay J. Weidenhamer

Masters Theses

Atherosclerosis is an inflammatory disease initiated by low and oscillatory shear stress on the endothelium. The inflammatory process recruits leukocytes to the vessel wall by expression of the adhesion molecule VCAM-1. Activation of the NF-κB inflammatory signaling pathway is responsible for the increase in VCM-1 expression. Omega 3 FAs, such as EPA, reduce the risk of atherosclerosis by decreasing this inflammatory response. The pathway by which omega 3 FAs is proposed to inhibit inflammation includes activating FFAR4 to decrease NF-κB activation thereby reducing expression of adhesion molecules. We hypothesized that treatment of endothelial cells with 30 μM EPA would decrease …

Link Between Muscle And Whole-Body Energetic Responses To Exercise, Christopher M.T. Hayden

Masters Theses

Substantial evidence exists regarding how skeletal muscles use energy and how this affects muscular performance. What remains unclear is how characteristics of muscle energetics affect whole-body energetics during daily living, and what effects this may have on mobility. The goal of this study was to determine the associations between muscle and whole-body energetics including the relationships between: 1) muscle PCr depletion (∆PCr) in response to light intensity isotonic contractions and the oxygen deficit at the onset of a 30-min treadmill walk (30MTW), and, 2) muscle oxidative capacity and excess post-exercise oxygen consumption (EPOC; 30MTW), respiratory exchange ratio (RER; 30MTW), and …

Seasonal Temperature Changes In Three Midwestern Wastewater Streams And The Effects On Fish Assemblages And Physiology, Ryan William Sparks

Masters Theses

Midwestern United States undergo extreme temperature and precipitation fluctuations throughout the year, which leads to changing habitats within Illinois river systems. Wastewater treatment facilities have long been used to treat sewage and reduce the organic products in sewage before releasing it into aquatic environments. Wastewater treatment facilities must maintain optimal conditions, especially temperature, for reproduction and growth of facilitated bacteria that break down organic materials in wastewater. The objectives for this study were to determine the thermal effects of wastewater treatment facilities on receiving waters; and secondly, to investigate the influence of these wastewater facilities on fish abundance and assemblages. …

The Effects Of Acidosis On Calcium Dependent Binding Of A Single Crossbridge, Matthew Unger

Masters Theses

Intracellular acidosis is a putative agent of skeletal muscle fatigue, in part, because acidosis depresses the calcium (Ca²⁺) sensitivity and force production of muscle (18, 50). However, the molecular mechanisms behind this depression in Ca²⁺ sensitivity and force production are unknown. This gap in knowledge poses a significant challenge in generating a complete understanding of the fatigue process. To close this gap, the ability of myosin to bind to a single actin filament was measured under acidic conditions, in a laser trap assay, with and without regulatory proteins. Decreasing pH from 7.4 to 6.5 reduced the frequency …

Mechanisms And Mitigation Of Skeletal Muscle Fatigue In Single Fibers From Older Adults, Aurora Foster

Masters Theses

Skeletal muscle fatigue is the contraction-induced decline in whole muscle force or power, and can be greater in older versus young adults. Fatigue primarily results from increased metabolism elevating phosphate (P_i) and hydrogen (H⁺), which alters myosin-actin interactions; however, which steps of the myosin-actin cross-bridge cycle are changed and their reversibility are unclear. PURPOSE: This study sought to: 1) Examine the effects of elevated P_i and H⁺ on molecular and cellular function, and 2) Test the ability of deoxyadenosine triphosphate (dATP), an alternative energy to adenosine triphosphate (ATP), to reverse the contractile changes induced …

The Role Of Creg1 As A Master Regulator Of Liver Function, Abdulrahman Siran Aldaghmi

Masters Theses

The liver is known as the chemical factory of the body because it performs a wide range of biochemical functions required for life. Since the liver has such an important role in regulation of normal physiological processes, liver diseases cause a high rate of morbidity and mortality. Therefore, understanding the mechanisms of liver development will shed light on the causes of liver disease. In this study, a cell line model that utilizes rat hepatoma cells (Fg14) and hepatoma variant cells (H11) was used to identify master regulators of liver gene expression. Whole genome expression studies identified the gene CREG1 (Cellular …

Metabolic And Morphologic Shifts In Neuro2a Cells Cultured In Galactose Medium, Leah Welker

Masters Theses

It has been observed that highly-proliferating cells, such as cancer cells, rely mainly on glycolysis for ATP production, regardless of presence of oxygen. This effect, however, can be reversed by changing the main energy substrate in the medium from glucose to galactose. The oxidation of galactose in glycolysis yields less net ATP, presumably forcing the cell into OXPHOS. This has been established in many cell lines, including HeLA, HepG2, and skeletal muscle cells. As of yet, this has not been reproduced in neuronal cells. Using Neuro2a, a murine neuroblastoma cell line, this study exposes neuronal cells to galactose medium, and …

Modifications Of Myofilament Structure And Function During Global Myocardial Ischemia, Mike K. Woodward

Masters Theses

Cardiac arrest is a prevalent condition with a poor prognosis, attributable in part to persistent myocardial dysfunction following resuscitation. The molecular basis of this dysfunction remains unclear. We induced cardiac arrest in a porcine model of acute sudden death and assessed the impact of ischemia and reperfusion on the molecular function of isolated cardiac contractile proteins. Cardiac arrest was electrically induced, left untreated for 12 min, and followed by a resuscitation protocol. With successful resuscitations, the heart was reperfused for 2 h (IR2) and the muscle harvested. In failed resuscitations, tissue samples were taken following the failed efforts (IDNR). Actin …

D-Galactose Decreases Mitoneet Levels In Liver Cancer Cells: Impact On Cellular Bioenergetics, Sudip Paudel

Masters Theses

Galactose is a simple sugar that at supraphysiological concentrations accelerates aging and age-related complications, which lead to impaired mitochondrial functions. MitoNEET is a small mitochondrial membrane protein with a molecular mass of 12.2 kDa that functions in diabetes, iron metabolism, regulation of oxidative phosphorylation (OXPHOS) and reactive oxygen species (ROS) homeostasis. MitoNEET knockdown increases cellular respiration rates and ROS levels similar to galactose treatment. Pioglitazone, an antidiabetic drug, binds to mitoNEET and ameliorates galactose toxicity. Cellular mitoNEET levels, exposure of cells to galactose medium, and pioglitazone treatment directly influence cellular respiration. To elucidate the role of mitoNEET in galactose induced …

Rapid Method Of Processing Sperm For Nucleic Acid Extraction In Clinical Research, Matthew K. De Gannes

Masters Theses

Background: Sperm contain highly compact nuclei, inhibiting DNA extraction using traditional techniques. Current methods extracting sperm DNA involve lengthy lysis and no means of stabilizing DNA, hindering clinical research.

Objective: We sought to optimize an efficient method of extracting high quality human sperm DNA.

Methods: Sperm from three volunteers were isolated using PureCeption. We tested 1) proteinase K with DNA/RNA Shield, 2) DTT and TCEP as reducing agents, 3) QIAshredder homogenization, and 4) stability of sperm DNA fresh (baseline) or after 4 weeks of storage at 4^OC in DNA/RNA Shield using modified Quick-gDNA MiniPrep. DNA was PCR amplified …

The Effect Of Ergosterol On The Desaturation Of 14c-Labeled Oleic Acid In Tetrahymena, Maynard E. Neville Jr.

Masters Theses

The ciliated protozoan Tetrahymena pyriformis-Strain W desaturated ¹⁴C-labeled fatty acid substrate in both sterol supplemented (ergosterol) and nonsupplemented cultures. Cis-octadecenoic acid (¹⁴C-9-18:1), when added to the medium during the log phase of growth, was incorporated into the cells and also desaturated at the Δ⁶ and Δ¹² positions. The ¹⁴C labeled substrate and products, linoleate (9,12-18:2) or linolenate (6,9,12-18:3) were recovered and separated by silver-nitrate Unisil column chromatography. Initially, recovery of ¹⁴C compounds varied widely when expressed as the percent of total counts per minute recovered from column chromotography, and a variety of …