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Articles 1 - 15 of 15
Full-Text Articles in Life Sciences
Tracking The Progression Of Defects At The Neuromuscular Junction In Huntington's Disease, Katherine A. Trittschuh
Tracking The Progression Of Defects At The Neuromuscular Junction In Huntington's Disease, Katherine A. Trittschuh
Browse all Theses and Dissertations
Huntington’s disease (HD) is a genetic disorder associated with progressive cognitive and motor decline. Recent studies in HD models suggest primary peripheral pathologies arise independent of changes in the central nervous system. Our lab found defects in skeletal muscle occurring early in the progression of disease in transgenic R6/2 HD mice, resulting in membrane hyperexcitability. Additionally, there is evidence of decreased quantal content in late-stage R6/2 mice. Here, we investigate pre-synaptic and post-synaptic function at single neuromuscular junctions (NMJ) to make direct comparisons of disease progression in the muscle membrane and motor nerve terminal. We hypothesize that muscle membrane defects …
Tracking The Progression Of Defects At The Neuromuscular Junction In Huntington's Disease, Katherine A. Trittschuh
Tracking The Progression Of Defects At The Neuromuscular Junction In Huntington's Disease, Katherine A. Trittschuh
Browse all Theses and Dissertations
Huntington’s disease (HD) is a genetic disorder associated with progressive cognitive and motor decline. Recent studies in HD models suggest primary peripheral pathologies arise independent of changes in the central nervous system. Our lab found defects in skeletal muscle occurring early in the progression of disease in transgenic R6/2 HD mice, resulting in membrane hyperexcitability. Additionally, there is evidence of decreased quantal content in late-stage R6/2 mice. Here, we investigate pre-synaptic and post-synaptic function at single neuromuscular junctions (NMJ) to make direct comparisons of disease progression in the muscle membrane and motor nerve terminal. We hypothesize that muscle membrane defects …
Intracellular Hemin Is A Potent Inhibitor Of The Voltage-Gated Potassium Channel Kv10.1, Nirakar Sahoo, Kefan Yang, Alisa Bernert, Sandip M. Swain, Guido Gessner, Reinhard Kappl, Toni Kühl, Diana Imhof, Toshinori Hoshi, Roland Schönherr, Stefan H. Heinemann
Intracellular Hemin Is A Potent Inhibitor Of The Voltage-Gated Potassium Channel Kv10.1, Nirakar Sahoo, Kefan Yang, Alisa Bernert, Sandip M. Swain, Guido Gessner, Reinhard Kappl, Toni Kühl, Diana Imhof, Toshinori Hoshi, Roland Schönherr, Stefan H. Heinemann
Biology Faculty Publications and Presentations
Heme, an iron-protoporphyrin IX complex, is a cofactor bound to various hemoproteins and supports a broad range of functions, such as electron transfer, oxygen transport, signal transduction, and drug metabolism. In recent years, there has been a growing recognition of heme as a non-genomic modulator of ion channel functions. Here, we show that intracellular free heme and hemin modulate human ether à go-go (hEAG1, Kv10.1) voltage-gated potassium channels. Application of hemin to the intracellular side potently inhibits Kv10.1 channels with an IC50 of about 4 nM under ambient and 63 nM under reducing conditions in a weakly voltage-dependent manner, …
Modulation Of Kras Structure And Dynamics By Kras Ubiquitination And Membrane Depolarization, Vinay Nair
Modulation Of Kras Structure And Dynamics By Kras Ubiquitination And Membrane Depolarization, Vinay Nair
Dissertations & Theses (Open Access)
KRAS, a 21 kDa small GTPase protein, functions as a molecular switch playing a key role in regulating cell proliferation. Dysregulation of KRAS signaling by oncogenic mutations leads to uncontrolled cell proliferation, a hallmark of cancer cells. Attempts to therapeutically target oncogenic KRAS have led to limited success resulting in a need to identify new mechanisms to targeting KRAS. The interaction of KRAS with its regulators, effectors, and the membrane present one such avenue. In this study, we investigated how post-translational covalent and environmental modifications could modulate these interactions of KRAS. Using computational molecular dynamics simulations, nuclear magnetic resonance spectroscopy …
The Role Of Ehd2 In Endothelial Cells, Rachael Judson
The Role Of Ehd2 In Endothelial Cells, Rachael Judson
Electronic Theses and Dissertations
The role of EHD2 in terms of Cav1 interaction had not been previously characterized and was the main goal of this research. Cav1 has been shown to lead to the ubiquitination of Rac1. Because of this, the role of EHD2 in Rac1 regulation was investigated. An increase in long-term migration in endothelial cells was observed and suggested that EHD2 impacts the RhoA pathway instead of the Rac1 pathway. This lead to the hypothesis that EHD2 controls a part of the RhoA pathway. This hypothesis is supported by the loss of filamentous actin and an increase in serrated junctions in cells …
The Effect Of Diode Laser On The Life And Appearance Of White Ant (Psammotermes Hypostoma), Estabraq Mahmood Mahdi Msc, Sahar Naji Rashid Msc., Saeed Maher Lafta Ph.D., Arshad Mahdi Hamad Msc
The Effect Of Diode Laser On The Life And Appearance Of White Ant (Psammotermes Hypostoma), Estabraq Mahmood Mahdi Msc, Sahar Naji Rashid Msc., Saeed Maher Lafta Ph.D., Arshad Mahdi Hamad Msc
Karbala International Journal of Modern Science
This work focused on studying effect of diode laser on external appearance of white ants, and finding the percentage of mortality resulting from this beam of (650nm),(5mW),exposure times (60,70,80,90,100)sec at (3,5)cm for each exposure. The results recorded showed a clear increase in death rates, and increase in deformations as laser exposure times increased (higher percentage at lower distance), where laser was used to capture results of this therapeutic effect after passage time periods (12,24,48,72)hours. These results, show laser thermal effects resulting from its interaction with tissues, thermal propagation leads to ravage to the structures, thus to an increase death rates.
Quantitative Super-Resolution Microscopy To Assess Adhesion Of Neuronal Cells On Single-Layer Graphene Substrates, Silvia Scalisi, Francesca Pennacchietti, Sandeep Keshavan, Nathan D. Derr, Alberto Diaspro, Dario Pisignano, Agnieszka Pierzynska-Mach, Silvia Dante, Francesca Cella Zanacchi
Quantitative Super-Resolution Microscopy To Assess Adhesion Of Neuronal Cells On Single-Layer Graphene Substrates, Silvia Scalisi, Francesca Pennacchietti, Sandeep Keshavan, Nathan D. Derr, Alberto Diaspro, Dario Pisignano, Agnieszka Pierzynska-Mach, Silvia Dante, Francesca Cella Zanacchi
Biological Sciences: Faculty Publications
Single Layer Graphene (SLG) has emerged as a critically important nanomaterial due to its unique optical and electrical properties and has become a potential candidate for biomedical applications, biosensors, and tissue engineering. Due to its intrinsic 2D nature, SLG is an ideal surface for the development of large-area biosensors and, due to its biocompatibility, can be easily exploited as a substrate for cell growth. The cellular response to SLG has been addressed in different studies with high cellular affinity for graphene often detected. Still, little is known about the molecular mechanism that drives/regulates the cellular adhesion and migration on SLG …
Linking Ecomechanical Models And Functional Traits To Understand Phenotypic Diversity, T. E. Higham, L. A. Ferry, L. Schmitz, D. J. Irschick, S. Starko, P. S L Anderson, P. J. Bergmann, H. A. Jamniczky, L. R. Monteiro, D. Navon, J. Messier, E. Carrington, S. C. Farina, K. L. Feilich, L. P. Hernandez, Michele A. Johnson, S. M. Kawano, C. J. Law, S. J. Longo, C. H. Martin, P. T. Martone, A. Rico-Guevara, S. E. Santana, K. J. Niklas
Linking Ecomechanical Models And Functional Traits To Understand Phenotypic Diversity, T. E. Higham, L. A. Ferry, L. Schmitz, D. J. Irschick, S. Starko, P. S L Anderson, P. J. Bergmann, H. A. Jamniczky, L. R. Monteiro, D. Navon, J. Messier, E. Carrington, S. C. Farina, K. L. Feilich, L. P. Hernandez, Michele A. Johnson, S. M. Kawano, C. J. Law, S. J. Longo, C. H. Martin, P. T. Martone, A. Rico-Guevara, S. E. Santana, K. J. Niklas
Biology Faculty Research
Physical principles and laws determine the set of possible organismal phenotypes. Constraints arising from development, the environment, and evolutionary history then yield workable, integrated phenotypes. We propose a theoretical and practical framework that considers the role of changing environments. This 'ecomechanical approach' integrates functional organismal traits with the ecological variables. This approach informs our ability to predict species shifts in survival and distribution and provides critical insights into phenotypic diversity. We outline how to use the ecomechanical paradigm using drag-induced bending in trees as an example. Our approach can be incorporated into existing research and help build interdisciplinary bridges. Finally, …
Electrostatically Localized Proton Bioenergetics: Better Understanding Membrane Potential, James Weifu Lee
Electrostatically Localized Proton Bioenergetics: Better Understanding Membrane Potential, James Weifu Lee
Chemistry & Biochemistry Faculty Publications
In Mitchell's chemiosmotic theory, membrane potential Δψ was given as the electric potential difference across the membrane. However, its physical origin for membrane potential Δψ was not well explained. Using the Lee proton electrostatic localization model with a newly formulated equation for protonic motive force (pmf) that takes electrostatically localized protons into account, membrane potential has now been better understood as the voltage difference contributed by the localized surface charge density ([H-+L] + nΣ i=1 [M(i+)L]) at the liquid-membrane interface as in an electrostatically localized protons/cations-membrane-anions capacitor. That is, the origin of membrane …
A Structural And Dynamic Model For The Assembly Of Replication Protein A On Single-Stranded Dna, Luke A. Yates, Ricardo J. Aramayo, Nilisha Pokhrel, Colleen C. Caldwell, Joshua A. Kaplan, Rajika L. Perera, Maria Spies, Edwin Antony, Xiaodong Zhang
A Structural And Dynamic Model For The Assembly Of Replication Protein A On Single-Stranded Dna, Luke A. Yates, Ricardo J. Aramayo, Nilisha Pokhrel, Colleen C. Caldwell, Joshua A. Kaplan, Rajika L. Perera, Maria Spies, Edwin Antony, Xiaodong Zhang
Biological Sciences Faculty Research and Publications
Replication Protein A (RPA), the major eukaryotic single stranded DNA-binding protein, binds to exposed ssDNA to protect it from nucleases, participates in a myriad of nucleic acid transactions and coordinates the recruitment of other important players. RPA is a heterotrimer and coats long stretches of single-stranded DNA (ssDNA). The precise molecular architecture of the RPA subunits and its DNA binding domains (DBDs) during assembly is poorly understood. Using cryo electron microscopy we obtained a 3D reconstruction of the RPA trimerisation core bound with ssDNA (∼55 kDa) at ∼4.7 Å resolution and a dimeric RPA assembly on ssDNA. FRET-based solution studies …
Microenvironment Regulates Fusion Of Breast Cancer Cells, Peiran Zhu
Microenvironment Regulates Fusion Of Breast Cancer Cells, Peiran Zhu
Masters Theses
Fusion of cancer cells has been observed in tumors for more than a century and is thought to contribute to tumor development and drug resistance. The low frequency of cell fusion events and the instability of fused cells have hindered our ability to understand the molecular mechanisms that govern cell fusion. We have developed a patterned gel system that can isolate cell fusion events and we demonstrate that several breast cancer cell lines can fuse into multinucleated giant cells in vitro, and the initiation and longevity of fused cells can be regulated solely by biophysical factors. Dynamically tuning the adhesive …
Utilizing Phluorin-Tagged Receptors To Monitor Subcellular Localization And Trafficking, Ashley M. Fox-Loe, Brandon J. Henderson, Christopher I. Richards
Utilizing Phluorin-Tagged Receptors To Monitor Subcellular Localization And Trafficking, Ashley M. Fox-Loe, Brandon J. Henderson, Christopher I. Richards
Chemistry Faculty Publications
Understanding membrane protein trafficking, assembly, and expression requires an approach that differentiates between those residing in intracellular organelles and those localized on the plasma membrane. Traditional fluorescence-based measurements lack the capability to distinguish membrane proteins residing in different organelles. Cutting edge methodologies transcend traditional methods by coupling pH-sensitive fluorophores with total internal reflection fluorescence microscopy (TIRFM). TIRF illumination excites the sample up to approximately 150 nm from the glass-sample interface, thus decreasing background, increasing the signal to noise ratio, and enhancing resolution. The excitation volume in TIRFM encompasses the plasma membrane and nearby organelles such as the peripheral ER. Superecliptic …
Ric-8a, A G Protein Chaperone With Nucleotide Exchange Activity Induces Long-Range Secondary Structure Changes In Gα, Ravi Kant, Baisen Zeng, Celestine J. Thomas, Brian Bothner, Stephen R. Sprang
Ric-8a, A G Protein Chaperone With Nucleotide Exchange Activity Induces Long-Range Secondary Structure Changes In Gα, Ravi Kant, Baisen Zeng, Celestine J. Thomas, Brian Bothner, Stephen R. Sprang
Biological Sciences Faculty Publications
Cytosolic Ric-8A has guanine nucleotide exchange factor (GEF) activity and is a chaperone for several classes of heterotrimeric G protein α subunits in vertebrates. Using Hydrogen-Deuterium Exchange-Mass Spectrometry (HDX-MS) we show that Ric-8A disrupts the secondary structure of the Gα Ras-like domain that girds the guanine nucleotide-binding site, and destabilizes the interface between the Gαi1 Ras and helical domains, allowing domain separation and nucleotide release. These changes are largely reversed upon binding GTP and dissociation of Ric-8A. HDX-MS identifies a potential Gα interaction site in Ric-8A. Alanine scanning reveals residues crucial for GEF activity within that sequence. HDX confirms that, …
Isolation And Biophysical Study Of Fruit Cuticles, Subhasish Chatterjee, Sayantani Sarkar, Julia Oktawiec, Zhantong Mao, Olivia Niitsoo, Ruth E. Stark
Isolation And Biophysical Study Of Fruit Cuticles, Subhasish Chatterjee, Sayantani Sarkar, Julia Oktawiec, Zhantong Mao, Olivia Niitsoo, Ruth E. Stark
Publications and Research
The cuticle, a hydrophobic protective layer on the aerial parts of terrestrial plants, functions as a versatile defensive barrier to various biotic and abiotic stresses and also regulates water flow from the external environment.1 A biopolyester (cutin) and long-chain fatty acids (waxes) form the principal structural framework of the cuticle; the functional integrity of the cuticular layer depends on the outer 'epicuticular' layer as well as the blend consisting of the cutin biopolymer and 'intracuticular' waxes.2 Herein, we describe a comprehensive protocol to extract waxes exhaustively from commercial tomato (Solanum lycopersicum) fruit cuticles or to remove epicuticular and intracuticular waxes …
Species Boundaries And Evolutionary Lineages In The Blue Green Damselfishes Chromis Viridis And Chromis Atripectoralis (Pomacentridae), Philadelphia University
Species Boundaries And Evolutionary Lineages In The Blue Green Damselfishes Chromis Viridis And Chromis Atripectoralis (Pomacentridae), Philadelphia University
Philadelphia University, Jordan
No abstract provided.