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Full-Text Articles in Physics
Modulation Of Voltage-Gating And Hysteresis Of Lysenin Channels By Cu2+ Ions, Andrew Bogard, Pangaea W. Finn, Aviana R. Smith, Ilinca M. Flacau, Rose Whiting, Daniel Fologea
Modulation Of Voltage-Gating And Hysteresis Of Lysenin Channels By Cu2+ Ions, Andrew Bogard, Pangaea W. Finn, Aviana R. Smith, Ilinca M. Flacau, Rose Whiting, Daniel Fologea
Physics Faculty Publications and Presentations
The intricate voltage regulation presented by lysenin channels reconstituted in artificial lipid membranes leads to a strong hysteresis in conductance, bistability, and memory. Prior investigations on lysenin channels indicate that the hysteresis is modulated by multivalent cations which are also capable of eliciting single-step conformational changes and transitions to stable closed or sub-conducting states. However, the influence on voltage regulation of Cu2+ ions, capable of completely closing the lysenin channels in a two-step process, was not sufficiently addressed. In this respect, we employed electrophysiology approaches to investigate the response of lysenin channels to variable voltage stimuli in the presence …
Hypo-Osmotic Stress And Pore-Forming Toxins Adjust The Lipid Order In Sheep Red Blood Cell Membranes, Rose Whiting, Sevio Stanton, Maryna Kucheriava, Aviana R. Smith, Matt Pitts, Daniel Robertson, Jacob Kammer, Zhiyu Li, Daniel Fologea
Hypo-Osmotic Stress And Pore-Forming Toxins Adjust The Lipid Order In Sheep Red Blood Cell Membranes, Rose Whiting, Sevio Stanton, Maryna Kucheriava, Aviana R. Smith, Matt Pitts, Daniel Robertson, Jacob Kammer, Zhiyu Li, Daniel Fologea
Physics Faculty Publications and Presentations
Lipid ordering in cell membranes has been increasingly recognized as an important factor in establishing and regulating a large variety of biological functions. Multiple investigations into lipid organization focused on assessing ordering from temperature-induced phase transitions, which are often well outside the physiological range. However, particular stresses elicited by environmental factors, such as hypo-osmotic stress or protein insertion into membranes, with respect to changes in lipid status and ordering at constant temperature are insufficiently described. To fill these gaps in our knowledge, we exploited the well-established ability of environmentally sensitive membrane probes to detect intramembrane changes at the molecular level. …
The Ionic Selectivity Of Lysenin Channels In Open And Sub-Conducting States, Andrew Bogard, Pangaea W. Finn, Fulton Mckinney, Ilinca M. Flacau, Aviana R. Smith, Rosey Whiting, Daniel Fologea
The Ionic Selectivity Of Lysenin Channels In Open And Sub-Conducting States, Andrew Bogard, Pangaea W. Finn, Fulton Mckinney, Ilinca M. Flacau, Aviana R. Smith, Rosey Whiting, Daniel Fologea
Physics Faculty Publications and Presentations
The electrochemical gradients established across cell membranes are paramount for the execution of biological functions. Besides ion channels, other transporters, such as exogenous pore-forming toxins, may present ionic selectivity upon reconstitution in natural and artificial lipid membranes and contribute to the electrochemical gradients. In this context, we utilized electrophysiology approaches to assess the ionic selectivity of the pore-forming toxin lysenin reconstituted in planar bilayer lipid membranes. The membrane voltages were determined from the reversal potentials recorded upon channel exposure to asymmetrical ionic conditions, and the permeability ratios were calculated from the fit with the Goldman–Hodgkin–Katz equation. Our work shows that …
Rapid Production And Purification Of Dye-Loaded Liposomes By Electrodialysis-Driven Depletion, Gamid Abatchev, Andrew Bogard, Zoe Hutchinson, Jason Ward, Daniel Fologea
Rapid Production And Purification Of Dye-Loaded Liposomes By Electrodialysis-Driven Depletion, Gamid Abatchev, Andrew Bogard, Zoe Hutchinson, Jason Ward, Daniel Fologea
Physics Faculty Publications and Presentations
Liposomes are spherical-shaped vesicles that enclose an aqueous milieu surrounded by bilayer or multilayer membranes formed by self-assembly of lipid molecules. They are intensively exploited as either model membranes for fundamental studies or as vehicles for delivery of active substances in vivo and in vitro. Irrespective of the method adopted for production of loaded liposomes, obtaining the final purified product is often achieved by employing multiple, time consuming steps. To alleviate this problem, we propose a simplified approach for concomitant production and purification of loaded liposomes by exploiting the Electrodialysis-Driven Depletion of charged molecules from solutions. Our investigations show that …
Temporary Membrane Permeabilization Via The Pore-Forming Toxin Lysenin, Nisha Shrestha, Christopher A. Thomas, Devon Richtsmeier, Andrew Bogard, Rebecca Hermann, Malyk Walker, Gamid Abatchev, Raquel J. Brown, Daniel Fologea
Temporary Membrane Permeabilization Via The Pore-Forming Toxin Lysenin, Nisha Shrestha, Christopher A. Thomas, Devon Richtsmeier, Andrew Bogard, Rebecca Hermann, Malyk Walker, Gamid Abatchev, Raquel J. Brown, Daniel Fologea
Physics Faculty Publications and Presentations
Pore-forming toxins are alluring tools for delivering biologically-active, impermeable cargoes to intracellular environments by introducing large conductance pathways into cell membranes. However, the lack of regulation often leads to the dissipation of electrical and chemical gradients, which might significantly affect the viability of cells under scrutiny. To mitigate these problems, we explored the use of lysenin channels to reversibly control the barrier function of natural and artificial lipid membrane systems by controlling the lysenin’s transport properties. We employed artificial membranes and electrophysiology measurements in order to identify the influence of labels and media on the lysenin channel’s conductance. Two cell …
Ribonucleoprotein Purification And Characterization Using Rna Mango, Shanker Shyam S. Panchapakesan, Matthew L. Ferguson, Eric J. Hayden, Xin Chen, Aaron A. Hoskins, Peter J. Unrau
Ribonucleoprotein Purification And Characterization Using Rna Mango, Shanker Shyam S. Panchapakesan, Matthew L. Ferguson, Eric J. Hayden, Xin Chen, Aaron A. Hoskins, Peter J. Unrau
Physics Faculty Publications and Presentations
The characterization of RNA–protein complexes (RNPs) is a difficult but increasingly important problem in modern biology. By combining the compact RNA Mango aptamer with a fluorogenic thiazole orange desthiobiotin (TO1-Dtb or TO3-Dtb) ligand, we have created an RNA tagging system that simplifies the purification and subsequent characterization of endogenous RNPs. Mango-tagged RNP complexes can be immobilized on a streptavidin solid support and recovered in their native state by the addition of free biotin. Furthermore, Mango-based RNP purification can be adapted to different scales of RNP isolation ranging from pull-down assays to the isolation of large amounts of biochemically defined cellular …
Cytotoxicity Of Zno Nanoparticles Can Be Tailored By Modifying Their Surface Structure: A Green Chemistry Approach For Safer Nanomaterials, Alex Punnoose, Kelsey Dodge, John W. Rasmussen, Jordan Chess, Denise Wingett, Catherine Anders
Cytotoxicity Of Zno Nanoparticles Can Be Tailored By Modifying Their Surface Structure: A Green Chemistry Approach For Safer Nanomaterials, Alex Punnoose, Kelsey Dodge, John W. Rasmussen, Jordan Chess, Denise Wingett, Catherine Anders
Physics Faculty Publications and Presentations
ZnO nanoparticles (NP) are extensively used in numerous nanotechnology applications; however, they also happen to be one of the most toxic nanomaterials. This raises significant environmental and health concerns and calls for the need to develop new synthetic approaches to produce safer ZnO NP, while preserving their attractive optical, electronic, and structural properties. In this work, we demonstrate that the cytotoxicity of ZnO NP can be tailored by modifying their surface-bound chemical groups, while maintaining the core ZnO structure and related properties. Two equally sized (9.26 ± 0.11 nm) ZnO NP samples were synthesized from the same zinc acetate precursor …
The Influences Of Cell Type And Zno Nanoparticle Size On Immune Cell Cytotoxicity And Cytokine Induction, Cory Hanley, Aaron Thurber, Charles Hanna, Alex Punnoose, Jianhui Zhang, Denise G. Wingett
The Influences Of Cell Type And Zno Nanoparticle Size On Immune Cell Cytotoxicity And Cytokine Induction, Cory Hanley, Aaron Thurber, Charles Hanna, Alex Punnoose, Jianhui Zhang, Denise G. Wingett
Physics Faculty Publications and Presentations
Nanotechnology represents a new and enabling platform that promises to provide a range of innovative technologies for biological applications. ZnO nanoparticles of controlled size were synthesized, and their cytotoxicity towards different human immune cells evaluated. A differential cytotoxic response between human immune cell subsets was observed, with lymphocytes being the most resistant and monocytes being the most susceptible to ZnO nanoparticle-induced toxicity. Significant differences were also observed between previously activated memory lymphocytes and naive lymphocytes, indicating a relationship between cell-cycle potential and nanoparticle susceptibility. Mechanisms of toxicity involve the generation of reactive oxygen species, with monocytes displaying the highest levels, …