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Calcium

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Articles 1 - 30 of 37

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Alzheimer's And Amyloid Beta: Amyloidogenicity And Tauopathy Via Dyshomeostatic Interactions Of Amyloid Beta, Jordan Tillinghast Dec 2019

Alzheimer's And Amyloid Beta: Amyloidogenicity And Tauopathy Via Dyshomeostatic Interactions Of Amyloid Beta, Jordan Tillinghast

Senior Honors Theses

This paper reviews functions of Amyloid-β (Aβ) in healthy individuals compared to the consequences of aberrant Aβ in Alzheimer’s disease (AD). As extraneuronal Aβ accumulation and plaque formation are characteristics of AD, it is reasonable to infer a pivotal role for Aβ in AD pathogenesis. Establishing progress of the disease as well as the mechanism of neurodegeneration from AD have proven difficult (Selkoe, 1994). This thesis provides evidence suggesting the pathogenesis of AD is due to dysfunctional neuronal processes involving Aβ’s synaptic malfunction, abnormal interaction with tau, and disruption of neuronal homeostasis. Significant evidence demonstrates that AD symptoms ...


Smooth Muscle Cell-Specific Tmem16a Deletion Does Not Alter Ca2+ Signaling, Uterine Contraction, Gestation Length Or Litter Size In Micedagger, Mingzi Qu, Ping Lu, Karl D. Bellve, Kevin E. Fogarty, Lawrence M. Lifshitz, Fangxiong Shi, Ronghua Zhuge Jun 2019

Smooth Muscle Cell-Specific Tmem16a Deletion Does Not Alter Ca2+ Signaling, Uterine Contraction, Gestation Length Or Litter Size In Micedagger, Mingzi Qu, Ping Lu, Karl D. Bellve, Kevin E. Fogarty, Lawrence M. Lifshitz, Fangxiong Shi, Ronghua Zhuge

Program in Molecular Medicine Publications and Presentations

Ion channels in myometrial cells play critical roles in spontaneous and agonist-induced uterine contraction during the menstrual cycle, pregnancy maintenance and parturition; thus identifying the genes of ion channels in these cells and determining their roles are essential to understanding the biology of reproduction. Previous studies with in vitro functional and pharmacological approaches have produced controversial results regarding the presence and role of TMEM16A Ca2+-activated Cl- channels in myometrial cells. To unambiguously determine the function of this channel in these cells, we employed a genetic approach by using smooth muscle cell-specific TMEM16A deletion (i.e. TMEM16ASMKO) mice. We found ...


Renal Risk Variants Of Apolipoprotein L-1 Form Channels At The Plasma Membrane That Lead To A Cytotoxic Influx Of Calcium, Joseph A. Giovinazzo Sep 2018

Renal Risk Variants Of Apolipoprotein L-1 Form Channels At The Plasma Membrane That Lead To A Cytotoxic Influx Of Calcium, Joseph A. Giovinazzo

All Dissertations, Theses, and Capstone Projects

Apolipoprotein L-1 (APOL1) is a secreted protein that provides protection against several protozoan parasites due to its channel forming properties. Recently evolved variants, G1 and G2, increase kidney disease risk when present in two copies. In mammalian cells, overexpression of G1 and G2, but not wild-type G0, leads to swelling and eventual lysis. However, the mechanism of cell death remains elusive with multiple pathways being invoked, such as autophagic cell death mediated by a BH3 domain in APOL1, which we evaluated in this study. We hypothesized that the common trigger for these pathways is the APOL1 cation channel, which is ...


Amylin And Diabetic Cardiomyopathy – Amylin-Induced Sarcolemmal Ca2+ Leak Is Independent Of Diabetic Remodeling Of Myocardium, Miao Liu, Amanda Hoskins, Nirmal Verma, Donald M. Bers, Sanda Despa, Florin Despa May 2018

Amylin And Diabetic Cardiomyopathy – Amylin-Induced Sarcolemmal Ca2+ Leak Is Independent Of Diabetic Remodeling Of Myocardium, Miao Liu, Amanda Hoskins, Nirmal Verma, Donald M. Bers, Sanda Despa, Florin Despa

Pharmacology and Nutritional Sciences Faculty Publications

Amylin is a pancreatic β-cell hormone co-secreted with insulin, plays a role in normal glucose homeostasis, and forms amyloid in the pancreatic islets of individuals with type-2 diabetes. Aggregated amylin is also found in blood and extra-pancreatic tissues, including myocardium. Myocardial amylin accumulation is associated with myocyte Ca2+ dysregulation in diabetic rats expressing human amylin. Whether deposition of amylin in the heart is a consequence of or a contributor to diabetic cardiomyopathy remains unknown. We used amylin knockout (AKO) mice intravenously infused with either human amylin (i.e, the aggregated form) or non-amyloidogenic (i.e., monomeric) rodent amylin to ...


A Discrete Loop In Serca N-Domain Plays A Role In Serca Headpiece Dynamics And Function, Olga N. Raguimova Jan 2018

A Discrete Loop In Serca N-Domain Plays A Role In Serca Headpiece Dynamics And Function, Olga N. Raguimova

Dissertations

The sarco/endoplasmic reticulum calcium ATPase (SERCA) is the major regulator of Ca2+ levels in the cell. Deficient calcium handling in the heart has been linked to heart failure, a leading cause of death in developed countries. As of today, targeting SERCA to enhance cardiac function has not been successful due to lack of details about SERCA structural dynamics during Ca2+ transport.

In my research, I utilized MD simulations and variety of physical assays to determine the role of Nβ5-β6 loop in regulation of SERCA structural dynamics during Ca2+ transport. Previous MD simulations by our lab predicted that the Nβ5-β6 ...


Observing The Molecular Basis Of Thin Filament Activation With A Three Bead Laser Trap Assay, Thomas Longyear Jan 2018

Observing The Molecular Basis Of Thin Filament Activation With A Three Bead Laser Trap Assay, Thomas Longyear

Doctoral Dissertations

Muscle contracts after calcium (Ca++) is released into the muscle cell, resulting from a cascade of events which result in myosin, the molecular motor of muscle, to produce force and motion. Myosin cyclically binds to a regulated thin filament, using the chemical energy of ATP to produce force and motion. Perturbations in muscle, such as a build-up of metabolic by-products or point mutations in key contractile proteins, can inhibit these functions in both skeletal and cardiac muscle either acutely or chronically. Despite the many years we have studied skeletal and cardiac muscle, we still do not have a clear picture ...


Mutant Tdp-43 Does Not Impair Mitochondrial Bioenergetics In Vitro And In Viv, Hibiki Kawamata, Pablo Peixoto, Csaba Konrad, Gloria Palomo, Kirsten Bredvik, Meri Gerges, Federica Valsecchi, Leonard Petrucelli, John M. Ravits, Anatoly Starkov, Giovanni Manfredi May 2017

Mutant Tdp-43 Does Not Impair Mitochondrial Bioenergetics In Vitro And In Viv, Hibiki Kawamata, Pablo Peixoto, Csaba Konrad, Gloria Palomo, Kirsten Bredvik, Meri Gerges, Federica Valsecchi, Leonard Petrucelli, John M. Ravits, Anatoly Starkov, Giovanni Manfredi

Publications and Research

Background: Mitochondrial dysfunction has been linked to the pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Functional studies of mitochondrial bioenergetics have focused mostly on superoxide dismutase 1 (SOD1) mutants, and showed that mutant human SOD1 impairs mitochondrial oxidative phosphorylation, calcium homeostasis, and dynamics. However, recent reports have indicated that alterations in transactivation response element DNA-binding protein 43 (TDP-43) can also lead to defects of mitochondrial morphology and dynamics. Furthermore, it was proposed that TDP-43 mutations cause oxidative phosphorylation impairment associated with respiratory chain defects and that these effects were caused by mitochondrial localization of the mutant ...


Calcium's Role As Nuanced Modulator Of Cellular Physiology In The Brain, Hilaree N. Frazier, Shaniya Maimaiti, Katie L. Anderson, Lawrence D. Brewer, John C. Gant, Nada M. Porter, Olivier Thibault Feb 2017

Calcium's Role As Nuanced Modulator Of Cellular Physiology In The Brain, Hilaree N. Frazier, Shaniya Maimaiti, Katie L. Anderson, Lawrence D. Brewer, John C. Gant, Nada M. Porter, Olivier Thibault

Pharmacology and Nutritional Sciences Faculty Publications

Neuroscientists studying normal brain aging, spinal cord injury, Alzheimer’s disease (AD) and other neurodegenerative diseases have focused considerable effort on carefully characterizing intracellular perturbations in calcium dynamics or levels. At the cellular level, calcium is known for controlling life and death and orchestrating most events in between. For many years, intracellular calcium has been recognized as an essential ion associated with nearly all cellular functions from cell growth to degeneration. Often the emphasis is on the negative impact of calcium dysregulation and the typical worse-case-scenario leading inevitably to cell death. However, even high amplitude calcium transients, when executed acutely ...


Role Of Energy Metabolism In The Thermogenic Gene Program, Minwoo Nam Jan 2017

Role Of Energy Metabolism In The Thermogenic Gene Program, Minwoo Nam

GSBS Dissertations and Theses

In murine and human brown adipose tissue (BAT), mitochondria are powerful generators of heat. Emerging evidence has suggested that the actions of mitochondria extend beyond this conventional biochemical role. In mouse BAT and cultured brown adipocytes, impaired mitochondrial respiratory capacity is accompanied by attenuated expression of Ucp1, a key thermogenic gene, implying a mitochondrial retrograde signaling. However, few have investigated this association in the context of mitochondria-nucleus communication.

Using mice with adipose-specific ablation of LRPPRC, a regulator of respiratory capacity, we show that respiration-dependent retrograde signaling from mitochondria to nucleus contributes to transcriptional and metabolic reprogramming of BAT. Impaired respiratory ...


Mitochondrial Calcium Uniporter Is A Nodal Regulator Of Physiological And Pathological Stress Responses In Myocardium, Tyler Paul Rasmussen May 2016

Mitochondrial Calcium Uniporter Is A Nodal Regulator Of Physiological And Pathological Stress Responses In Myocardium, Tyler Paul Rasmussen

Theses and Dissertations

A long held hypothesis in mitochondrial biology holds that increases in mitochondrial Ca2+ levels stimulate the activity of matrix dehydrogenases that catalyze production of NADH and eventually donate electrons to electron transport in order to increase ATP formation. At the same time, mitochondrial Ca2+ overload is a deleterious event leading to opening of the mitochondrial permeability transition pore, increasing reactive oxygen species and initiating pathways that contribute to cell death. These fundamental hypotheses are best studied in the heart because of the critical energy supply-demand relationship in myocardium, but were untestable in vivo until the discovery of the ...


Protein-Ligand Interactions And Allosteric Regulation Of Activity In Dream Protein, Walter G. Gonzalez Mar 2016

Protein-Ligand Interactions And Allosteric Regulation Of Activity In Dream Protein, Walter G. Gonzalez

FIU Electronic Theses and Dissertations

Downstream regulatory antagonist modulator (DREAM) is a calcium sensing protein that co-assembles with KV4 potassium channels to regulate ion currents as well as with DNA in the nucleus, where it regulates gene expression. The interaction of DREAM with A-type KV4 channels and DNA has been shown to regulate neuronal signaling, pain sensing, and memory retention. The role of DREAM in modulation of pain, onset of Alzheimer’s disease, and cardiac pacemaking has set this protein as a novel therapeutic target. Moreover, previous results have shown a Ca2+ dependent interaction between DREAM and KV4 ...


Calcium (Ii) Catalyzed Nitrone Additions, Elizabeth A. Congdon Jan 2016

Calcium (Ii) Catalyzed Nitrone Additions, Elizabeth A. Congdon

Honors Theses

Calcium(II) complexes have be shown to be successful catalysts for nitrone reactions. The addition of n-­‐methyl and n-­‐phenyl nitrones to donor-­‐acceptor cyclopropanes was achieved with calcium triflate (Ca(OTf). Differentially substituted tetrahydro-­‐1,2-­‐oxazines were synthesized in good to excellent yields. Calcium triflate was also found to catalyze the addition of silyl enol ethers to n-­‐phenyl nitrones along the Mukaiyama-­‐Mannich addition pathway. B-­‐amino carbonyls were synthesized from a variety of substituted nitrones. Bulky and cyclic silyl enol ethers were also found to be reactive, the products of which were isolated in good ...


Calmodulin-Like Protein 38: A Component Of Ribonucleoprotein Particles During Hypoxic Stress Responses In Arabidopsis, Ansul Lokdarshi Aug 2015

Calmodulin-Like Protein 38: A Component Of Ribonucleoprotein Particles During Hypoxic Stress Responses In Arabidopsis, Ansul Lokdarshi

Doctoral Dissertations

Waterlogging stress leads to a crisis in energy metabolism and the accumulation of toxic metabolites due to the hypoxic and/or anoxic environment associated with this condition. To respond and adapt to this situation, higher plants employ an integrated genetic program that leads to the induction of anaerobic response polypeptide genes that encode metabolic and signaling proteins involved in altering metabolic flow and other adaptive responses. The study presented here shows that the Arabidopsis thaliana calmodulin-like protein CML38 is calcium sensor protein that serves as a member of the core anaerobic response gene family and is involved in modulating the ...


Gating Mechanisms Of The Canonical Trp Channel Isoform Trpc4, Dhananjay P. Thakur Aug 2015

Gating Mechanisms Of The Canonical Trp Channel Isoform Trpc4, Dhananjay P. Thakur

UT GSBS Dissertations and Theses (Open Access)

Non-selective cation channels formed by Transient Receptor Potential Canonical (TRPC) proteins play important roles in regulatory and pathophysiological processes. These channels are known to be activated downstream from phospholipase C (PLC) signaling. However, the mechanism by which the PLC pathway activates TRPC4/C5 remains unclear. Uniquely, TRPC4 is maximally activated only when two separate G protein pathways, Gq/11 and Gi/o, are co-stimulated, making it a coincidence detector of Gq/11- and Gi/o -coupled receptor activation. Using HEK293 cells co-expressing mouse TRPC4β and selected G protein-coupled receptors, I observed that coincident stimulation of G ...


Role Of Non-Muscle Myosin Ii And Calcium In Zebrafish Midbrain-Hindbrain Boundary Morphogenesis, Srishti Upasana Sahu May 2015

Role Of Non-Muscle Myosin Ii And Calcium In Zebrafish Midbrain-Hindbrain Boundary Morphogenesis, Srishti Upasana Sahu

Theses and Dissertations

Elucidating the molecular mechanisms that play a role in cellular morphogenesis is critical to our understanding of brain development and function. The midbrain-hindbrain boundary (MHB) is one of the first folds in the vertebrate embryonic brain and is highly conserved across species. We used the zebrafish MHB as a model for determining the molecular mechanisms that regulate these cell shape changes. Cellular morphogenesis is tightly regulated by signaling pathways that rearrange the cytoskeleton and produce mechanical forces that enable changes in cell and tissue morphology. The generation of force within a cell often depends on motor proteins, particularly non-muscle myosins ...


Chemical Biology-Based Probes For The Labeling Of Targets On Live Cells, Amanda M. Hussey Jan 2015

Chemical Biology-Based Probes For The Labeling Of Targets On Live Cells, Amanda M. Hussey

Doctoral Dissertations

Proper detection is the key to studying any processes on the cellular scale. Nowhere is this more evident than in the tight space which confines the synaptic cleft. Being able to ascertain the location of receptors on live neurons is fundamental to our understanding of not only how these receptors interact and move inside the cell but also how neurons function. Most detection methods rely on significantly altering the receptor; both tagging with a fluorescent protein or targeting the receptor by a fluorescent reporter in the form of a small molecule causes significant difficulties. These localization techniques often result in ...


A Novel Role For Nf-Κb In Proximal T Cell Signaling, Crystina Bronk Watson Nov 2014

A Novel Role For Nf-Κb In Proximal T Cell Signaling, Crystina Bronk Watson

Graduate Theses and Dissertations

The interrogation of T cell signaling over the past fifty years has led to the discovery of amazingly intricate cascade networks and elaborate descriptions of individual proteins' domains and functions. A complex landscape has been rendered in which proteins relay messages from the extracellular ligation of the TCR by a cognate peptide loaded MHC via changes in sub-cellular location, phosphorylation, and binding affinities and partners to enact nuclear localization of three key transcription factors required for cellular effector function and proliferation: AP-1, NF-AT, and NF-κB. Dogma has favored activation of each of these transcription regulating elements to be a linear ...


Bipolar Nanosecond Electric Pulses Are Less Efficient At Electropermeabilization And Killing Cells Than Monopolar Pulses, Bennett L. Ibey, Olga N. Pakhomova, Caleb C. Roth, Shu Xiao, Karl Schoenbach, Andrei G. Pakhomov Jan 2014

Bipolar Nanosecond Electric Pulses Are Less Efficient At Electropermeabilization And Killing Cells Than Monopolar Pulses, Bennett L. Ibey, Olga N. Pakhomova, Caleb C. Roth, Shu Xiao, Karl Schoenbach, Andrei G. Pakhomov

Bioelectrics Publications

Multiple studies have shown that bipolar (BP) electric pulses in the microsecond range are more effective at permeabilizing cells while maintaining similar cell survival rates as compared to monopolar (MP) pulse equivalents. In this paper, we investigated whether the same advantage existed for BP nanosecond-pulsed electric fields (nsPEF) as compared to MP nsPEF. To study permeabilization effectiveness, MP or BP pulses were delivered to single Chinese hamster ovary (CHO) cells and the response of three dyes, Calcium Green-1, propidium iodide (PI), and FM1-43, was measured by confocal microscopy. Results show that BP pulses were less effective at increasing intracellular calcium ...


Calcium-Mediated Pore Expansion And Cell Death Following Nanoelectroporation, Olga N. Pakhomova, Betsy Gregory, Iurii Semenov, Andrei G. Pakhomov Jan 2014

Calcium-Mediated Pore Expansion And Cell Death Following Nanoelectroporation, Olga N. Pakhomova, Betsy Gregory, Iurii Semenov, Andrei G. Pakhomov

Bioelectrics Publications

Opening of long-lived pores in the cell membrane is the principal primary effect of intense, nanosecond pulsed electric field (nsPEF). Here we demonstrate that the evolution of pores, cell survival, the time and the mode of cell death (necrotic or apoptotic) are determined by the level of external Ca2+ after nsPEF. We also introduce a novel, minimally disruptive technique for nsEP exposure of adherent cells on indium tin oxide (ITO)-coated glass coverslips, which does not require cell detachment and enables fast exchanges of bath media. Increasing the Ca2+ level from the nominal 2–5 μM to 2 ...


Characterization Of Caxck31, A Bacterial Calcium/Proton Antiporter, Marc Robert Ridilla Oct 2013

Characterization Of Caxck31, A Bacterial Calcium/Proton Antiporter, Marc Robert Ridilla

Open Access Dissertations

To better understand a class of transporters known as Calcium/Cation Antiporters (CaCAs), the bacterial calcium/proton antiporter CAXCK31 was purified and characterized. New methods were developed for its heterologous overexpression and purification. These methods help to define stress responses to toxic membrane overproduction in E. coli and may be broadly applicable to studies of membrane proteins. The results from a variety of biochemical and biophysical experiments demonstrated that CAXCK31 exists as a dimer in the membrane and can be purified in the dimeric state. The methods used include chemical cross-linking, FRET, and SEC-MALS. In addition, various transport properties of ...


Post-Injury Calcium Chelation Rescues Skeletal Muscle Regeneration In Mice, Matthew D. Magda Aug 2013

Post-Injury Calcium Chelation Rescues Skeletal Muscle Regeneration In Mice, Matthew D. Magda

Honors Scholar Theses

During aging the ability of skeletal muscle to regenerate after injury wanes until muscle integrity cannot be maintained. In this study it is shown that calcium chelation can restore young-like regenerative ability in an aged mouse model of skeletal muscle regeneration.


Estradiol Modulation Of Calcium Dynamics In Pituitary Mmq Lactotroph Cells, Monika Pauckova Jan 2012

Estradiol Modulation Of Calcium Dynamics In Pituitary Mmq Lactotroph Cells, Monika Pauckova

Electronic Theses and Dissertations

Pituitary lactotrophs are excitable cells that exhibit spontaneous, calcium influx triggering prolactin (PRL) secretion to stimulate lactation. Lactotrophs express estrogen receptors (ER) and are a well established estrogen-responsive cell system. 17B-estradiol (E2) is known to directly affect lactotrophs by increasing PRL transcription and biosynthesis, intracellular Ca2+ concentration ([Ca2+]i) and PRL secretion. This study demonstrates that the MMQ clonal cell line, isolated from the 7315a rat pituitary tumor, is a model lactotroph cell line that is E2-responsive. Spontaneous and evoked Ca2+ transients were especially sensitive to L-type channel block, but not affected by block of omega-conotoxin-GVIA-sensitive CaV channels or TTX-sensitive ...


The Csc Is Required For Complete Radial Spoke Assembly And Wild-Type Ciliary Motility, Erin E. Dymek, Thomas Heuser, Daniela Nicastro, Elizabeth F. Smith May 2011

The Csc Is Required For Complete Radial Spoke Assembly And Wild-Type Ciliary Motility, Erin E. Dymek, Thomas Heuser, Daniela Nicastro, Elizabeth F. Smith

Open Dartmouth: Faculty Open Access Scholarship

The ubiquitous calcium binding protein, calmodulin (CaM), plays a major role in regulating the motility of all eukaryotic cilia and flagella. We previously identified a CaM and Spoke associated Complex (CSC) and provided evidence that this complex mediates regulatory signals between the radial spokes and dynein arms. We have now used an artificial microRNA (amiRNA) approach to reduce expression of two CSC subunits in Chlamydomonas. For all amiRNA mutants, the entire CSC is lacking or severely reduced in flagella. Structural studies of mutant axonemes revealed that assembly of radial spoke 2 is defective. Furthermore, analysis of both flagellar beating and ...


An Apoptosis Targeted Stimulus With Nanosecond Pulsed Electric Fields (Nspefs) In E4 Squamous Cell Carcinoma, Wei Ren, Stephen J. Beebe Jan 2011

An Apoptosis Targeted Stimulus With Nanosecond Pulsed Electric Fields (Nspefs) In E4 Squamous Cell Carcinoma, Wei Ren, Stephen J. Beebe

Bioelectrics Publications

Stimuli directed towards activation of apoptosis mechanisms are an attractive approach to eliminate evasion of apoptosis, a ubiquitous cancer hallmark. In these in vitro studies, kinetics and electric field thresholds for several apoptosis characteristics are defined in E4 squamous carcinoma cells (SCC) exposed to ten 300 ns pulses with increasing electric fields. Cell death was [95% at the highest electric field and coincident with phosphatidylserine externalization, caspase and calpain activation in the presence and absence of cytochrome c release, decreases in Bid and mitochondria membrane potential (Δψm) without apparent changes reactive oxygen species levels or in Bcl2 and Bclxl levels ...


Altered Calcium Handling In Cerebellar Purkinje Neurons With The Malignant Hyperthermia Mutation, Ryr1-Y522s/+, George C. Talbott Jan 2011

Altered Calcium Handling In Cerebellar Purkinje Neurons With The Malignant Hyperthermia Mutation, Ryr1-Y522s/+, George C. Talbott

Electronic Theses and Dissertations

To investigate the etiology of malignant hyperthermia and central core disease, mouse models have recently been generated and characterized (Chelu et al., 2006). These RyRY522S/+ knock-in mutant mice provide an excellent tool to investigate calcium dysregulation, its pathological consequences, and potential therapeutic approaches. Skeletal muscle harboring this mutation exhibits calcium leak from internal stores and an increased sensitivity to activation by caffeine, voltage, and temperature (Durham et al., 2008). Although alterations in RyR1 channel function and resultant changes in cellular function have been characterized in skeletal muscle, the effects of MH mutations in RyR1 on central nervous system function have ...


Efficient Activation Of Reconstructed Rat Embryos By Cyclin-Dependent Kinase Inhibitors, Robin L. Webb, Kirk A. Findlay, Michael A. Green, Tina L. Beckett, M. Paul Murphy Mar 2010

Efficient Activation Of Reconstructed Rat Embryos By Cyclin-Dependent Kinase Inhibitors, Robin L. Webb, Kirk A. Findlay, Michael A. Green, Tina L. Beckett, M. Paul Murphy

Molecular and Cellular Biochemistry Faculty Publications

Background

Over the last decade a number of species, from farm animals to rodents, have been cloned using somatic cell nuclear transfer technology (SCNT). This technique has the potential to revolutionize the way that genetically modified animals are made. In its current state, the process of SCNT is very inefficient (<5% success rate), with several technical and biological hurdles hindering development. Yet, SCNT provides investigators with powerful advantages over other approaches, such as allowing for prescreening for the desired level of transgene expression and eliminating the excess production of undesirable wild-type animals. The rat plays a significant role in biomedical research, but SCNT has been problematic for this species. In this study, we address one aspect of the problem by evaluating methods of activation in artificially constructed rat embryos.

Principal Findings

We demonstrate that treatment with a calcium ionophore (ionomycin) combined with a variety of cyclin-dependent kinase inhibitors is an effective way to activate rat embryos. This is in contrast to methods developed for the mouse embryo, which tolerates much less specific chemical treatments. Methods developed to activate mouse ...


Ionic Selectivity In L-Type Calcium Channels By Electrostatics And Hard-Core Repulsion, Dezso Boda, Douglas Henderson, Monika Valisko, Bob Eisenberg, Dirk Gillespie Apr 2009

Ionic Selectivity In L-Type Calcium Channels By Electrostatics And Hard-Core Repulsion, Dezso Boda, Douglas Henderson, Monika Valisko, Bob Eisenberg, Dirk Gillespie

Faculty Publications

A physical model of selective "ion binding" in the L-type calcium channel is constructed, and consequences of the model are compared with experimental data. This reduced model treats only ions and the carboxylate oxygens of the EEEE locus explicitly and restricts interactions to hard-core repulsion and ion–ion and ion–dielectric electrostatic forces. The structural atoms provide a flexible environment for passing cations, thus resulting in a self-organized induced-fit model of the selectivity filter. Experimental conditions involving binary mixtures of alkali and/or alkaline earth metal ions are computed using equilibrium Monte Carlo simulations in the grand canonical ensemble. The ...


Calcium And Cell Volume Regulation In Alligator Mississippiensis Erythrocytes, Alina Spivak Apr 2008

Calcium And Cell Volume Regulation In Alligator Mississippiensis Erythrocytes, Alina Spivak

Eukaryon

Maintenance of proper cell volume is critical for cell survival and proliferation; consequently, animal cells routinely control their volume to maintain homeostasis. For instance, biological processes such as the response to ischemia (insufficient blood flow), lymphocyte activation, and apoptosis (programmed cell death) are associated with changes in cell volume. It has been well established that osmotic swelling associated with a hypotonic medium is followed by a regulated volume decrease (RVD) resulting from the efflux of specific solutes. However, the signaling mechanisms of RVD are ill defined. The effect of calcium on RVD was studied because this ion is a common ...


The Endocytic Protein Numb Regulates App Metabolism And Notch Signaling: Implications For Alzheimer's Disease, George Kyriazis Jan 2008

The Endocytic Protein Numb Regulates App Metabolism And Notch Signaling: Implications For Alzheimer's Disease, George Kyriazis

Electronic Theses and Dissertations

Increased production of amyloid beta (A-beta) peptide, via altered proteolytic cleavage of amyloid protein precursor (APP), and abnormalities in neuronal calcium homeostasis play central roles in the pathogenesis of Alzheimer's disease (AD). Notch1, a membrane receptor that controls cell fate decisions during development of the nervous system, has been linked to AD because it is a substrate for the gamma-secretase protein complex in which mutations cause early-onset inherited AD. Numb is an evolutionarily conserved endocytic adapter involved in the internalization of transmembrane receptors. Mammals produce four Numb isoforms that differ in two functional domains, a phosphotyrosine-binding domain (PTB) and ...


Light-Evoked Calcium Responses Of Isolated Melanopsin- Expressing Retinal Ganglion Cells, Andrew T. E. Hartwick, Jayne R. Bramley, Jianing Yu, Kelly T. Stevens, Charles N. Allen, William H. Baldridge, Patricia J. Sollars, Gary E. Pickard Dec 2007

Light-Evoked Calcium Responses Of Isolated Melanopsin- Expressing Retinal Ganglion Cells, Andrew T. E. Hartwick, Jayne R. Bramley, Jianing Yu, Kelly T. Stevens, Charles N. Allen, William H. Baldridge, Patricia J. Sollars, Gary E. Pickard

Papers in Veterinary and Biomedical Science

A small number (<2%) of mammalian retinal ganglion cells express the photopigment melanopsin and are intrinsically photosensitive (ipRGCs). Light depolarizes ipRGCs and increases intracellular calcium levels ( [Ca2+]i ) but the signaling cascades underlying these responses have yet to be elucidated. To facilitate physiological studies on these rare photoreceptors, highly enriched ipRGC cultures from neonatal rats were generated using anti-melanopsin-mediated plate adhesion (immunopanning). This novel approach enabled experiments on isolated ipRGCs, eliminating the potential confounding influence of rod/cone-driven input. Light induced a rise in [Ca2+]i (monitored using fura-2 imaging) in the immunopanned ipRGCs and the source of this Ca2+ signal was investigated. The Ca2+ responses were inhibited by 2-aminoethoxydiphenyl borate, SKF-96365 (1–2-(4-methoxyphenyl)-2-[3-(4-methoxyphenyl)propoxy]ethyl- ...