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Full-Text Articles in Physiology

The Effects Of Resistance Exercise Training On Insulin Resistance Development In Female Rodents With Type 1 Diabetes, Mitchell James Sammut Aug 2023

The Effects Of Resistance Exercise Training On Insulin Resistance Development In Female Rodents With Type 1 Diabetes, Mitchell James Sammut

Electronic Thesis and Dissertation Repository

The etiology of insulin resistance (IR) development in type 1 diabetes mellitus (T1DM) remains unclear; however, impaired skeletal muscle metabolism may play a role. While IR development has been established in male T1DM rodents, female rodents have yet to be examined in this context. Resistance exercise training (RT) has been shown to improve IR and is associated with a lower risk of hypoglycemia onset in T1DM compared to aerobic exercise. Additionally, the molecular mechanisms mediating RT-induced improvements in insulin sensitivity remain unclear. Therefore, the purpose of this study was to investigate the effects of RT on IR development in female …


The Effect Of Breathing Patterns Common To Competitive Swimming On Gas Exchange And Muscle Deoxygenation During Heavy-Intensity Fartlek Exercise, Kevin J. Grossman May 2022

The Effect Of Breathing Patterns Common To Competitive Swimming On Gas Exchange And Muscle Deoxygenation During Heavy-Intensity Fartlek Exercise, Kevin J. Grossman

Electronic Thesis and Dissertation Repository

The purpose of this study was to compare the respiratory and muscle deoxygenation (HHb) responses of regulated breathing versus free-breathing, during continuous exercise (CONLD) and intermittent 5s breath holds (BH) (CONLD-BH), intermittent 5s sprint (FLK) and combined 5s BH and sprint (FLK-BH) followed by 25s of free-breathing. Oxygen uptake(V̇O2)was unchanged between CONLD (2.12±0.35L/min) and CONLD-BH (2.15±0.42L/min; p=0.116), and FLK (2.24±0.40L/min) and FLK-BH (2.20±0.45L/min; p=0.861). Δ[Hbtot]: CONLD (3.3±1.6µM) > CONLD-BH (-2.5±1.2µM; ∆177%; p<0.001), but unchanged between FLK (2.0±1.6µM) and FLK-BH (0.82±1.4µM; p=0.979). Δ[HHb]: CONLD (7.3±1.8µM) > CONLD-BH (7.0±2.0µM; ∆4%; p=0.011), and FLK (6.7±1.8µM) < FLK-BH (8.7±2.4µM; p<0.001). It is suggested that the unchanged V̇O2 between CONLD and CONLD-BH was supported by increased deoxygenation, reflected by decreased ∆[Hbtot] and blunted …


Biochemistry Of Trehalose Accumulation In The Spring Field Cricket, Gryllus Veletis, Alyssa R. Stephens May 2022

Biochemistry Of Trehalose Accumulation In The Spring Field Cricket, Gryllus Veletis, Alyssa R. Stephens

Electronic Thesis and Dissertation Repository

The freeze tolerant spring field cricket, Gryllus veletis, accumulates trehalose in the blood and tissues during cold acclimation. Trehalose is the main blood sugar in insects, thus its blood concentration is tightly regulated, and trehalose is readily metabolized. How do crickets modify their metabolism to accumulate trehalose in their hemolymph and tissues? I hypothesized that trehalose production, transport, and consumption were modified during the cold acclimation to facilitate trehalose accumulation. Trehalose and the trehalose-specific transporter, TRET-1, are distributed among all tissues, and trehalose accumulates in the hemolymph, fat body, Malpighian tubules, and gut. Trehalose production increases during cold acclimation …


The Hydrophobic Residues In Amino Terminal Domains Of Cx46 And Cx50 Are Important For Their Gap Junction Channel Ion Permeation And Gating, Roa'a Jaradat May 2022

The Hydrophobic Residues In Amino Terminal Domains Of Cx46 And Cx50 Are Important For Their Gap Junction Channel Ion Permeation And Gating, Roa'a Jaradat

Electronic Thesis and Dissertation Repository

Connexins are ubiquitous transmembrane proteins that assemble to form intercellular channels, called gap junctions (GJs). The amino terminal (NT) domain and residues within this domain have been shown to be important for both Vj-gating and single channel conductance (γj) of several GJs including Cx46 and Cx50. High-resolution structures of Cx46 and Cx50 GJs were recently resolved showing that NT domain folds into the inner pore where hydrophobic residues are packed against M1/2 domains stabilizing open-state conformation. We studied functional properties of GJs formed by several point variants at NT (Cx46 L10I, N13E, A14V, Q15N and Cx50 …


Characterizing The Structural, Biophysical And Functional Effects Of S-Glutathionylation On Stim1 Ca2+ Sensing, Christian Michael Sirko Aug 2021

Characterizing The Structural, Biophysical And Functional Effects Of S-Glutathionylation On Stim1 Ca2+ Sensing, Christian Michael Sirko

Electronic Thesis and Dissertation Repository

Stromal interaction molecule 1 (STIM1) is an endo/sarcoplasmic reticulum (ER/SR) calcium (Ca2+) sensing protein that initiates cytoplasmic Ca2+ influx via store-operated calcium entry (SOCE). STIM1, in conjunction with Orai, a plasma membrane (PM) protein, function as mediators of SOCE through the formation of calcium-release activated calcium (CRAC) channels. S-Glutathionylation of STIM1 at Cys56 has been shown to evoke constitutive Ca2+ entry in DT40 cells, however no studies have carefully investigated the biophysical and structural effects of this covalent modification to the luminal domain, which are critical for understanding the molecular mechanism underlying the regulation of …


Characterization Of Mechanotransduction In Annulus Fibrosus Cells, Min Kyu M. Kim Aug 2020

Characterization Of Mechanotransduction In Annulus Fibrosus Cells, Min Kyu M. Kim

Electronic Thesis and Dissertation Repository

IVD degeneration is a multifactorial pathological process associated with back pain. While biomechanical factors are important regulators of IVD homeostasis, mechanical loading also contribute to the onset of IVD degeneration. Importantly, the mechanotransduction pathways that mediate cell type-specific responses to mechanical loading are not well understood. Transient receptor potential vanilloid 4 (TRPV4) is a multimodally activated cell surface cation channel implicated as a mechanoreceptor regulating the mechano-response in other musculoskeletal cell types. Using both in vitro and in vivo models, the current study aimed to characterize the role of TRPV4 in annulus fibrosus (AF) cell mechanotransduction. Using a mechanically dynamic …


The Amino Terminal Domains Of Sheep Cx46 Or Cx50 Determine Their Gap Junction Channel Open Stability And Unitary Channel Conductance, Benny Yue Jun 2020

The Amino Terminal Domains Of Sheep Cx46 Or Cx50 Determine Their Gap Junction Channel Open Stability And Unitary Channel Conductance, Benny Yue

Electronic Thesis and Dissertation Repository

Connexins form intercellular communication channels known as gap junctions (GJs), which are found throughout the vertebrate species. GJs formed by different connexins harbor unique channel properties that have not been fully defined. High-resolution structures of native Cx46 and Cx50 GJs from sheep (sCx46 and sCx50) were recently resolved. Molecular dynamics studies identified the NT domains, especially the 9th position, as key determinants in the differences of energetic barrier to K+ permeation in sCx46 and sCx50 GJs. We studied functional properties of GJs formed by sCx46, sCx50, NT domain swapped chimeras (sCx46-50NT and sCx50-46NT), and point variants at the …


Excess No Stabilizes The Luminal Domain Of Stim2 In A Cys-Specific Manner Thereby Regulating Basal Calcium Homeostasis And Store-Operated Calcium Entry, Matthew Novello Sep 2019

Excess No Stabilizes The Luminal Domain Of Stim2 In A Cys-Specific Manner Thereby Regulating Basal Calcium Homeostasis And Store-Operated Calcium Entry, Matthew Novello

Electronic Thesis and Dissertation Repository

Stromal-interaction molecule 2 (STIM2) is an endoplasmic reticulum (ER) membrane-inserted Ca2+-sensing protein which, together with the plasma membrane Ca2+ channel Orai1, regulates basal Ca2+ homeostasis and store-operated Ca2+ entry (SOCE). Recent evidence suggests that S-nitrosylation, which is the covalent attachment of a nitric oxide (NO) moiety to a cysteine thiol, can attenuate the function of the paralog STIM1 protein. Compared to STIM1, STIM2 also functions as a basal Ca2+ homeostatic feedback regulator. Therefore, the objective of my study was to evaluate the susceptibility of STIM2 to S-nitrosylation and the effects that this …


Assessing The Structure-Function Relationships Of The Apolipoprotein(A) Kringle Iv Sub-Type 10 Domain, Matthew J. Borrelli Aug 2019

Assessing The Structure-Function Relationships Of The Apolipoprotein(A) Kringle Iv Sub-Type 10 Domain, Matthew J. Borrelli

Electronic Thesis and Dissertation Repository

Elevated plasma lipoprotein(a) (Lp(a)) is the most prevalent heritable risk factor in the development of cardiovascular disease. The apolipoprotein(a) (apo(a)) component of Lp(a) is strongly implicated in the pathogenicity of Lp(a). It is hypothesized that the inflammatory potential of Lp(a)/apo(a) is mediated by the lysine binding ability of the apo(a) kringle IV10 (KIV10) domain, along with its covalently bound oxidized phospholipid (oxPL). Using targeted mutagenesis, two novel null alleles for the LPA gene that generate non-secretable apo(a) species have been identified, resulting from amino acid substitutions in the KIV10 domain. A potential mechanism by which KIV10 oxPL modification is enriched …


Effects Of Maternal Protein Restriction On The Pulmonary Surfactant System During The Early Life And Adulthood, Reza Khazaee Oct 2018

Effects Of Maternal Protein Restriction On The Pulmonary Surfactant System During The Early Life And Adulthood, Reza Khazaee

Electronic Thesis and Dissertation Repository

Fetal growth restriction (FGR) is defined by low birth weight and contributes to a variety of adult-onset diseases with different severities between males and females. However, the effects of FGR on the pulmonary surfactant are not fully elucidated. In this thesis, first, we investigated the FGR effects on the lung function and the surfactant system at the early postnatal life. It was hypothesized that FGR contributes to alterations of lung mechanics and the surfactant system during the neonatal period. Second, we assessed the FGR effects on the surfactant system in response to sepsis in adulthood. It was hypothesized that FGR …


Defective Aba-Mediated Sugar Signalling Pathway In An Established Arabidopsis Thaliana Cell Suspension Culture Explains Its Stay-Green Phenotype At High Sugar Concentrations, Avery Mccarthy Jun 2018

Defective Aba-Mediated Sugar Signalling Pathway In An Established Arabidopsis Thaliana Cell Suspension Culture Explains Its Stay-Green Phenotype At High Sugar Concentrations, Avery Mccarthy

Electronic Thesis and Dissertation Repository

An unusual sugar insensitive phenotype was identified in an established cell suspension culture of Arabidopsis thaliana. We characterized the physiology, biochemistry and genetics of the sugar insensitive cell culture, in order to identify factors contributing to the phenotype. Chlorophyll levels of the cell suspension culture were insensitive to high sucrose (6-15% w/v) and maintained a green phenotype. Immunoblotting indicated that levels of key photosynthetic proteins (PsaA, Lhcb2 and Rubisco) increased as a function of external sucrose concentration. The green cell culture was photosynthetically competent based on light-dependent, CO2-saturated rates of O2 evolution as well as Fv/Fm …


Regulation Of Liver Mitochondrial Metabolism During Hibernation By Post-Translational Modification, Katherine E. Mathers Dec 2017

Regulation Of Liver Mitochondrial Metabolism During Hibernation By Post-Translational Modification, Katherine E. Mathers

Electronic Thesis and Dissertation Repository

Hibernation, characterized by a seasonal reduction in metabolism and body temperature, allows animals to conserve energy when environmental conditions (e.g. temperature, food availability) are unfavourable. During hibernation, small mammals such as the 13-lined ground squirrel (Ictidomys tridecemlineatus) cycle between two distinct metabolic states: torpor, where metabolic rate is suppressed by >95% and body temperature falls to ~5 °C, and interbout euthermia (IBE), where metabolic rate and body temperature rapidly increase and are maintained at euthermic levels several hours. Suppression of metabolism during entrance into torpor is paralleled by rapid suppression of liver mitochondrial metabolism. In my thesis, I …


Cal And Magi Pdz Protein Regulation Of Crfr1 And 5-Ht2ar Trafficking And Signaling, Maha Mahmoud Hammad Aug 2016

Cal And Magi Pdz Protein Regulation Of Crfr1 And 5-Ht2ar Trafficking And Signaling, Maha Mahmoud Hammad

Electronic Thesis and Dissertation Repository

PDZ (PSD95/Disc Large/Zona Occludens) domain-containing proteins are scaffolding proteins that play important roles in regulating the activity of G protein-coupled receptors. Corticotropin Releasing Factor Receptor 1 (CRFR1) and Serotonin 2A Receptor (5-HT2AR) are two GPCRs that are commonly associated with mental disorders. Both receptors also contain a class I PDZ-binding motif at the carboxyl terminal tail. In the first chapter, we investigate the effects of CAL (CFTR-associated ligand) on regulating the trafficking and signaling of CRFR1. We demonstrate a role for CAL in inhibiting CRFR1 endocytosis, cell surface expression, and CRF-mediated ERK1/2 signaling via the CRFR1 PDZ-binding motif. …


Molecular Mechanisms Underlying The Early Life Programming Of The Liver, Gurjeev Sohi Jul 2013

Molecular Mechanisms Underlying The Early Life Programming Of The Liver, Gurjeev Sohi

Electronic Thesis and Dissertation Repository

Clinical studies have demonstrated that intrauterine growth restriction (IUGR) offspring, faced with a nutritional mismatch postpartum, have an increased risk of developing the metabolic syndrome. The maternal protein restriction (MPR) rat model has been extensively studied to investigate the adverse effects of a nutritional mismatch in postnatal life of IUGR offspring. Previous studies have demonstrated that MPR leads to impaired function of the liver, an important metabolic organ. However the underlying mechanisms which predispose these offspring to the metabolic syndrome remain elusive. In the following studies, low protein diet during pregnancy and lactation led to IUGR offspring with decreased liver …


Elongation Factor 1a-1 And Hepatocyte Response To Fatty Acid Excess, Alexandra M. Stoianov Apr 2013

Elongation Factor 1a-1 And Hepatocyte Response To Fatty Acid Excess, Alexandra M. Stoianov

Electronic Thesis and Dissertation Repository

Obesity is associated with elevated levels of serum fatty acids, which accumulate in nonadipose tissues including the liver. Elongation factor 1A-1 (EF1A-1) has previously been shown to participate in the cell stress and death response of cardiomyocytes to excess saturated fatty exposure, and in steatotic mouse myocardium. In this thesis, the hypothesis that the hepatocyte response to fatty acid overload involves EF1A-1 was tested. EF1A-1 expression was induced in the livers of obese mice in association with severe hepatic steatosis, and in HepG2 human hepatoma cells in response to excess palmitate. Partial translocation of EF1A-1 from the ER to polymerized …


Identification And Characterization Of The Arabidopsis Homolog Of The Yeast Trex-2 Complex, Gang Tian May 2012

Identification And Characterization Of The Arabidopsis Homolog Of The Yeast Trex-2 Complex, Gang Tian

Electronic Thesis and Dissertation Repository

Nuclear pore complexes (NPCs) are vital to nuclear-cytoplasmic communication in eukaryotes. The yeast Thp1-Sac3-Cdc31-Sus1 complex, also known as the TREX-2 complex, is anchored to the NPC via the nucleoporin Nup1, and is essential for mRNA export. In this study, the Arabidopsis homolog of the yeast TREX-2 complex was discovered. Physical and functional evidence support the identification of the Arabidopsis orthologs of the yeast Thp1 and Nup1. Of three Sac3 Arabidopsis homologs, two are putative TREX-2 components. Surprisingly, none are required for mRNA export as is the yeast Sac3. Physical association with TREX-2 was observed for the two Cdc31 homologs, but …


Mitochondrial Metabolic Suppression And Reactive Oxygen Species Production During Hypometabolism In Mammals, Jason Cl Brown Jul 2011

Mitochondrial Metabolic Suppression And Reactive Oxygen Species Production During Hypometabolism In Mammals, Jason Cl Brown

Electronic Thesis and Dissertation Repository

During hibernation, daily torpor, and fasting, mammals reduce metabolic rate (MR) up to 99%, 95%, and 30%, respectively, compared to resting levels. Mitochondrial metabolic suppression likely contributes to this MR reduction, and the first objective of this study was to determine the relative contributions of active, regulated inhibition and passive thermal effects as body temperature (Tb) falls, to mitochondrial metabolic suppression, and to examine the mechanisms involved using top-down elasticity analysis and novel statistical approach. The second objective of this study was to determine how mitochondrial metabolic suppression affects mitochondrial reactive oxygen species (ROS) production, a topic which …