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

Recombinant Gelonin: Purification And Functional Validation For Electroporation-Assisted Delivery, Eleni Zivla, Giedrė Šilkūnienė, Andrei G. Pakhomov, Mantas Šilkūnas, Olga N. Pakhomova Mar 2026

Recombinant Gelonin: Purification And Functional Validation For Electroporation-Assisted Delivery, Eleni Zivla, Giedrė Šilkūnienė, Andrei G. Pakhomov, Mantas Šilkūnas, Olga N. Pakhomova

Knowledge and Creativity Expo

Type I ribosome-inactivating proteins, such as gelonin, are enzymatically potent toxins but are effectively non-toxic under physiological conditions because they are unable to cross the plasma membrane[1]. Pulsed electric fields (PEF) overcome this delivery barrier by transiently permeabilizing the plasma membrane, allowing direct cytosolic entry. This enhances gelonin cytotoxicity by several thousand-fold, highlighting gelonin’s potential as an electrochemotherapy candidate[2]. Here, we present a recombinant gelonin (rGel) expression platform in E. coli with HPLC-based purification that enables reproducible protein production and structure-guided engineering.

The mature gelonin sequence (residues 47–297) was cloned into pET-32a(+) with an N-terminally fused Trx-6×His tag and TEV …


Mxene-Enabled Wearable Biosensors: A Design Framework For Autonomous Biosensing, Jegan Rajendran, Gymama Slaughter Jan 2026

Mxene-Enabled Wearable Biosensors: A Design Framework For Autonomous Biosensing, Jegan Rajendran, Gymama Slaughter

Center for Bioelectronics Publications

MXenes, a rapidly expanding family of two-dimensional transition metal carbides and nitrides, have emerged as leading materials for wearable bioelectronics due to their metallic conductivity, termination-rich surfaces, mechanical compliance, and tunable interlayer structures. However, wearable biosensor performance does not arise from conductivity alone, but from coupled interactions among surface termination chemistry, heterointerface engineering, hierarchical architecture, and device integration under dynamic physiological conditions. This review establishes a predictive structure-interface-device framework linking MXene chemistry to system-level performance across electrochemical, mechanical, gas, optical, and energy-storage modalities. We analyze how termination-controlled adsorption governs charge transfer and selectivity, how heterojunction formation modulates carrier density and …


Recirculated Submarine Groundwater Discharge Dominates Nutrient Inputs And Enhances Eutrophication Risk In A Coastal Lagoon, Júlia Rodriguez-Puig, Clara Ruiz-González, Marc Diego-Feliu, Irene Alorda-Montiel, Aaron Alorda-Kleinglass, Daniel Romano-Gude, Andrea G. Bravo, Júlia Dordal-Soriano, Javier Gilabert, Sophia Bergeler, Celine Lavergne, Gemma Casas, Marisol Manzano, Jordi Garcia-Orellana, Valentí Rodellas Jan 2026

Recirculated Submarine Groundwater Discharge Dominates Nutrient Inputs And Enhances Eutrophication Risk In A Coastal Lagoon, Júlia Rodriguez-Puig, Clara Ruiz-González, Marc Diego-Feliu, Irene Alorda-Montiel, Aaron Alorda-Kleinglass, Daniel Romano-Gude, Andrea G. Bravo, Júlia Dordal-Soriano, Javier Gilabert, Sophia Bergeler, Celine Lavergne, Gemma Casas, Marisol Manzano, Jordi Garcia-Orellana, Valentí Rodellas

OES Faculty Publications

Submarine groundwater discharge (SGD) is a widely recognized pathway for nutrient transport to coastal systems. Prior studies overlook the unique biogeochemical signatures of different SGD pathways, neglecting their differences in biogeochemical transformations and spatiotemporal factors. Here, we present an integrated assessment of nutrient delivery through three SGD pathways (fresh SGD, long‐scale recirculated SGD, and short‐scale porewater exchange), alongside surface water inputs, to evaluate their seasonality and impact on nutrient dynamics in a coastal lagoon. We conducted five field surveys in March, July, and November 2021, July 2024, and March 2025 in the Mar Menor lagoon, an ecosystem facing severe ecological …


Characterization Of Phytoplankton-Excreted Metabolites Mediating Carbon Flux Through The Surface Ocean, Yuting Zhu, Hanna S. Anderson, Eli Salcedo, Samuel E. Miller, Krista Longnecker, Melissa C. Kido Soule, Sheean T. Haley, Gretchen J. Swarr, Rogier Braakman, Sonya T. Dyhrman, Elizabeth B. Kujawinski Jan 2026

Characterization Of Phytoplankton-Excreted Metabolites Mediating Carbon Flux Through The Surface Ocean, Yuting Zhu, Hanna S. Anderson, Eli Salcedo, Samuel E. Miller, Krista Longnecker, Melissa C. Kido Soule, Sheean T. Haley, Gretchen J. Swarr, Rogier Braakman, Sonya T. Dyhrman, Elizabeth B. Kujawinski

Chemistry & Biochemistry Faculty Publications

The marine labile dissolved organic carbon (DOC) pool is a dynamic reservoir of thousands of molecules that cycles approximately one-quarter of Earth’s primary production within days to weeks. After excretion by phytoplankton and other microbes, metabolites are rapidly consumed, resulting in low standing concentrations (picomolar to low nanomolar). Despite the decades-long search for labile DOC sources and molecular identities, marine phytoplankton exometabolomes are not well characterized, largely due to difficulties in measuring small polar molecules in saline water. Here, we profiled the exometabolomes of six axenic phytoplankton species representing key functional groups including a diatom (Thalassiosira pseudonana CCMP1335), a …


Mitochondria-Mediated Epigenetic Transfer Between Chondrosarcoma And Wild-Type Cells, Caleb C. J. Wyckoff Dec 2025

Mitochondria-Mediated Epigenetic Transfer Between Chondrosarcoma And Wild-Type Cells, Caleb C. J. Wyckoff

Biomedical Sciences Theses & Dissertations

Glioblastoma (GB), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), cholangiocarcinoma, and chondrosarcoma (CS) cancers all contain mutations in the gene isocitrate dehydrogenase 2 (IDH2). The mutant IDH2 enzyme exhibits transformation of alpha-ketoglutarate (αKG) into the oncometabolite D-2-hydroxyglutarate (D2HG) in the mitochondria of these cancers. Mitochondrial-mediated transfer between cancer cells and recipient cells is a significant event that impacts the physiology of the receiving cell, specifically the epigenetic landscape. Previous experiments indicating increased DNA methylation in mesenchymal stem cells exposed to IDH1 or IDH2 conditioned medium underscore the potential role of D2HG to alter methylation states. Additionally, the presence of …


Tracing The Journey Of Dissolved Organic Matter: From Leaf Litter Photodegradation To Microbial Processing In Tropical Streams, Samantha Nicole Sullivan Dec 2025

Tracing The Journey Of Dissolved Organic Matter: From Leaf Litter Photodegradation To Microbial Processing In Tropical Streams, Samantha Nicole Sullivan

Chemistry & Biochemistry Theses & Dissertations

Dissolved organic matter (DOM) is a major reservoir of organic carbon in aquatic ecosystems and plays a central role in global carbon cycling through its transformation and remineralization to carbon dioxide (CO₂). As DOM moves from terrestrial environments into streams and rivers, its chemical composition is altered by a combination of microbial and photochemical oxidation processes that regulate both its reactivity and its persistence during transport. However, the molecular mechanisms governing these oxidative transitions, particularly in tropical ecosystems characterized by strong hydrologic seasonality and substantial inputs of plant-derived material, remain insufficiently resolved. This dissertation integrates ultrahigh-resolution mass spectrometry, optical characterization, …


Using Radium Isotopes To Compare Nutrient Inputs Via Submarine Groundwater Discharge To Offshore Export On The West Florida Shelf, Andrew L. Lindgren Jul 2025

Using Radium Isotopes To Compare Nutrient Inputs Via Submarine Groundwater Discharge To Offshore Export On The West Florida Shelf, Andrew L. Lindgren

OES Theses and Dissertations

Radium isotopes have been used to trace submarine groundwater discharge (SGD) and associated nutrient and metal inputs into the coastal ocean. They have also been used to estimate rates of diffusive mixing and export fluxes of dissolved constituents offshore. However, use of both approaches in tandem to determine the fate of groundwater inputs after they enter the coastal ocean is still relatively unexplored. Radium isotopes and nutrients were measured in two cross-shelf cruises on the West Florida Shelf in different seasons and in quarterly sampling of offshore wells. Through 226Ra mass balance and 223Ra-derived diffusive mixing rates, inputs of nutrients …


Expanding The Lexa Bacterial Two-Hybrid System For Human Protein-Protein Interaction Screening: Application To Tumor Suppressor Par-4, Rebecca M. Richardson Apr 2025

Expanding The Lexa Bacterial Two-Hybrid System For Human Protein-Protein Interaction Screening: Application To Tumor Suppressor Par-4, Rebecca M. Richardson

Chemistry & Biochemistry Theses & Dissertations

Protein-protein interactions (PPI) are fundamental to cellular function, influencing processes such as signaling, structural organization, and disease progression. Disruptions in PPIs are implicated in cancer and neurodegenerative diseases, highlighting their importance as therapeutic targets. However, traditional methods for studying human PPIs, such as yeast two-hybrid and co-immunoprecipitation mass spectrometry, are costly and technically demanding. This dissertation explores the LexA-based bacterial two-hybrid (LexA-B2H) system as a cost effective and accessible alternative for investigating human PPIs.

This study focuses on the interaction between glucose-regulated protein 78 (GRP78) and cleaved prostate apoptosis response-4 (cl-Par-4), a tumor suppressor protein involved in apoptosis and neurodegenerative …


Low Dissolved Oxygen Operation Enhances Biological Phosphorus Removal In Wastewater Treatment, Haley Morgan Apr 2025

Low Dissolved Oxygen Operation Enhances Biological Phosphorus Removal In Wastewater Treatment, Haley Morgan

Civil & Environmental Engineering Theses & Dissertations

Biological phosphorus (bio-P) removal occurs when bacteria are exposed to anaerobic/aerobic conditions that stimulate polyphosphate-accumulating organisms (PAOs) to uptake phosphorus. In most treatment plants, dissolved oxygen (DO) concentrations in the aeration tanks are commonly at or above 2.0 mg O2/L, which is often referred to as the most optimal aeration condition for bio-P. If bio-P can happen efficiently at lower DO (< 0.3 mg O2/L), then the energy demand of aeration can be decreased appreciably. This research was conducted in a biological nutrient removal (BNR) pilot plant to assess the performance of bio-P at progressively lower DO operation. This …


Development Of Flexible Lactate-Specific Molecularly Imprinted Polymers Based On Laser-Induced Graphene Electrochemical Biosensors For Disease Diagnosis, Christopher Animashaun Apr 2025

Development Of Flexible Lactate-Specific Molecularly Imprinted Polymers Based On Laser-Induced Graphene Electrochemical Biosensors For Disease Diagnosis, Christopher Animashaun

Biomedical Engineering Theses & Dissertations

Lactate is a critical biomarker linked to conditions such as sepsis, ischemia, cancer, and heart failure. Current lactate detection methods remain invasive, costly, and unsuitable for real-time, continuous monitoring. This study presents the development of a flexible, non-enzymatic electrochemical biosensor based on laser-induced graphene (LIG) electrodes modified with gold nanoparticles (AuNPs) and molecularly imprinted polymers (MIPs) for highly selective and sensitive lactate measurement. The integration of AuNPs enhanced surface conductivity and provided nanoscale heterogeneity, facilitating superior signal amplification. The optimized LIG/AuNP/MIP sensor achieved an extensive dynamic detection range from 0.1 μM to 1000 μM, with an outstanding detection limit of …


Traction Force Microscopy Using An Epifluorescence Microscope: Experimental Considerations And Caveats, Zaria Booth, Mazen Mezher, Rudra Patel, Venkat Maruthamuthu Jan 2025

Traction Force Microscopy Using An Epifluorescence Microscope: Experimental Considerations And Caveats, Zaria Booth, Mazen Mezher, Rudra Patel, Venkat Maruthamuthu

Mechanical & Aerospace Engineering Faculty Publications

Forces exerted by cells due to their internal contractility play fundamental roles in a host of processes, including adhesion, migration, survival and differentiation. Traction force microscopy (TFM) enables the determination of forces exerted by cells or cell collectives on their environment, which is typically taken to be an extra-cellular matrix (ECM)-coated substrate. Sample preparation for TFM involves the plating of cells onto an environment embedded with fiducial markers. The imaging of these fiducial markers in the presence and absence of the cells then enables calculation of the displacement of localized regions of the environment, and, consequently, the spatial distribution of …


Transient Transmembrane-Electrostatically Localized Protons And Transmembrane Potential In A Laser Flashed Bacteriorhodopsin Purple Membrane Open Flat Sheet - Summary, James Weifu Lee Jan 2025

Transient Transmembrane-Electrostatically Localized Protons And Transmembrane Potential In A Laser Flashed Bacteriorhodopsin Purple Membrane Open Flat Sheet - Summary, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

The transmembrane-electrostatically localized protons/cations charges (TELCs, also known as TELPs) model may serve as a unified framework to explain a wide range of bioenergetic phenomena. Transient transmembrane-electrostatically localized protons (TELPs) and transmembrane potential in a laser flash-energized bacteriorhodopsin (bR) purple membrane (PM) open flat sheet are now better analyzed. Under the Heberle et al. (1994) experimental conditions, the number of bR molecules is now calculated to be 8200 per PM open flat sheet with a diameter of 600 nm. With a single-turnover laser flash intensity of 3 mJ/cm² to photoexcite 10% of the bR molecules, the laser flash-induced peak TELCs …


Electrochemical Detection Of Prostate Cancer—Associated Mirna-141 Using A Low-Cost Disposable Biosensor, Alexander Hunt, Gymama Slaughter Jan 2025

Electrochemical Detection Of Prostate Cancer—Associated Mirna-141 Using A Low-Cost Disposable Biosensor, Alexander Hunt, Gymama Slaughter

Center for Bioelectronics Publications

Prostate cancer is the second leading cause of cancer-related deaths among men in the United States. The early detection of aggressive forms is critical. Current diagnostic methods, including PSA testing and biopsies, are invasive and often yield false results. MicroRNA-141 (miRNA-141) has emerged as a promising non-invasive biomarker due to its elevated levels in the urine of patients with metastatic prostate cancer. Here, a low-cost, paper-based electrochemical biosensor for the sensitive detection of miRNA-141 in synthetic urine is reported. The device employs inkjet-printed gold electrodes on photopaper, functionalized with thiolated single-stranded DNA-141 capture probes for specific target recognition. The biosensor …


Electrical Homeostasis Of The Inner Mitochondrial Membrane Potential, Peyman Fahimi, Lázaro A. M. Castanedo, P. Thomas Vernier, Cherif F. Matta Jan 2025

Electrical Homeostasis Of The Inner Mitochondrial Membrane Potential, Peyman Fahimi, Lázaro A. M. Castanedo, P. Thomas Vernier, Cherif F. Matta

Bioelectrics Publications

The electric potential across the inner mitochondrial membrane must be maintained within certain bounds for the proper functioning of the cell. A feedback control mechanism for the homeostasis of this membrane potential is proposed whereby an increase in the electric field decreases the rate-limiting steps of the electron transport chain (ETC). An increase in trans-membrane electric field limits the rate of proton pumping to the inter-membrane gap by slowing the ETC reactions and by intrinsically induced electroporation that depolarizes the inner membrane. The proposed feedback mechanism is akin to a Le Chatelier's-type principle of trans-membrane potential feedback control.


Organic Geochemical Evidence For Life In Archean Rocks Identified By Pyrolysis-Gc-Ms And Supervised Machine Learning, Michael L. Wong, Anirudh Prabhu, Conel O'D. Alexander, H. James Cleaves Ii, George D. Cody, Grethe Hystad, Marko Bermanec, Wouter Bleeker, C. Kevin Boyce, Andrea Corpolongo, Andrew D. Czaja, Souvik Das, Robert R. Gaines, Daniel D. Gregory, John A. Jaszczak, Emmanuelle J. Javaux, Jaganmoy Jodder, Andrew H. Knoll, Martin Van Kranendonk, Katie M. Maloney, Nora Noffke, Robert Rainbird, Emersyn Slaughter, Eva E. Stüeken, Roger E. Summons, Frances Westall, Jasmina Wiemann, Shuhai Xiao, Robert M. Hazen Jan 2025

Organic Geochemical Evidence For Life In Archean Rocks Identified By Pyrolysis-Gc-Ms And Supervised Machine Learning, Michael L. Wong, Anirudh Prabhu, Conel O'D. Alexander, H. James Cleaves Ii, George D. Cody, Grethe Hystad, Marko Bermanec, Wouter Bleeker, C. Kevin Boyce, Andrea Corpolongo, Andrew D. Czaja, Souvik Das, Robert R. Gaines, Daniel D. Gregory, John A. Jaszczak, Emmanuelle J. Javaux, Jaganmoy Jodder, Andrew H. Knoll, Martin Van Kranendonk, Katie M. Maloney, Nora Noffke, Robert Rainbird, Emersyn Slaughter, Eva E. Stüeken, Roger E. Summons, Frances Westall, Jasmina Wiemann, Shuhai Xiao, Robert M. Hazen

OES Faculty Publications

Throughout Earth’s history, organic molecules from both abiogenic and biogenic sources have been buried in sedimentary rocks. Most of these organic molecules have been significantly altered by geologic processes through deep time. Nonetheless, the nature and distribution of those ancient fragmentary organic remains have the potential to reveal diagnostic biomolecular information after billions of years of burial. Here, we analyzed 406 fossil, modern biological, meteoritic, and synthetic samples using pyrolysis gas chromatography and mass spectrometry. We explored these analytical data via supervised machine-learning methods to discriminate samples of biogenic vs. abiogenic origin, plant vs. animal phylogenetic affinity, and photosynthetic vs. …


Green Chelation Strategy For Deashing Of Algal Biomass, Agyare Asante, George Daramola, Ryan W. Davis, Sandeep Kumar Jan 2025

Green Chelation Strategy For Deashing Of Algal Biomass, Agyare Asante, George Daramola, Ryan W. Davis, Sandeep Kumar

Civil & Environmental Engineering Faculty Publications

This study investigated a green chelation strategy for deashing algal biomass using nitrilotriacetic acid (NTA) and deionized water (DI) to enhance its suitability for biofuel and bioproduct applications. Solid-state algal turf scrubber (SS ATS), green algal turf scrubber (ATS), and Scenedesmus were analyzed, with Scenedesmus selected for detailed evaluation due to its high ash removal efficiency. The objective was to optimize a purification process that minimizes ash and heavy metal content while preserving biochemical integrity. Algal biomass underwent sequential washing with DI, NTA, and NTA+DI under varying temperatures (90-130 °C). Analytical techniques including Fourier Transform Infrared (FTIR) spectroscopy, Inductively Coupled …


Environmentally Friendly Chelation For Enhanced Algal Biomass Deashing, Agyare Asante, George Daramola, Ryan W. Davis, Sandeep Kumar Jan 2025

Environmentally Friendly Chelation For Enhanced Algal Biomass Deashing, Agyare Asante, George Daramola, Ryan W. Davis, Sandeep Kumar

Civil & Environmental Engineering Faculty Publications

High ash content in algal biomass limits its suitability for biofuel production by reducing combustion efficiency and increasing fouling. This study presents a green deashing strategy using nitrilotriacetic acid (NTA) and deionized (DI) water to purify Scenedesmus algae, which was selected for its high ash removal potential. The optimized sequential treatment (DI, NTA chelation, and DI+NTA treatment at 90–130 °C) achieved up to 83.07% ash removal, reducing ash content from 15.2% to 3.8%. Elevated temperatures enhanced the removal of calcium, magnesium, and potassium, while heavy metals like lead and copper were reduced below detection limits. CHN analysis confirmed minimal …


Extended Inter-Laboratory Characterization Of The New Coastal Seawater Dissolved Organic Matter Reference Material Trm-0522, Alexander J. Craig, Lydia Babcock-Adams, Maxime C. Bridoux, Charlotte Brun, Juliana D'Andrilli, Aleksandar I. Goranov, Patrick G. Hatcher, Oliver Lechtenfeld, Hang Li, Rebecca Matos, Garrett Mckay, Amy M. Mckenna, Madelyn Miller, Sasha Wagner, Margot E. White, Alexander Zherebker, Jeffrey A. Hawkes Jan 2025

Extended Inter-Laboratory Characterization Of The New Coastal Seawater Dissolved Organic Matter Reference Material Trm-0522, Alexander J. Craig, Lydia Babcock-Adams, Maxime C. Bridoux, Charlotte Brun, Juliana D'Andrilli, Aleksandar I. Goranov, Patrick G. Hatcher, Oliver Lechtenfeld, Hang Li, Rebecca Matos, Garrett Mckay, Amy M. Mckenna, Madelyn Miller, Sasha Wagner, Margot E. White, Alexander Zherebker, Jeffrey A. Hawkes

Chemistry & Biochemistry Faculty Publications

Dissolved organic matter (DOM) reference materials are critical to ensuring reliable comparability of measurements across experiments and between labs. TRM-0522, isolated in 2022 from 45 m deep seawater off of Sweden’s west coast, fills the niche of a previously unavailable coastal marine DOM reference material. After its isolation, we detailed a limited number of metrics for TRM-0522, initially disclosing Orbitrap high-resolution mass spectrometry, nuclear magnetic resonance, carbon proportion, absorbance, and fluorescence data. With TRM-0522 becoming more widely used, a variety of labs have generated different metrics that help to characterize and define the chemical properties of this coastal reference material. …


From Biophysics To Cellular Function: Neural Telcs-Membrane-Anions Capacitor Transmembrane Potential, James Weifu Lee Jan 2025

From Biophysics To Cellular Function: Neural Telcs-Membrane-Anions Capacitor Transmembrane Potential, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

Based on the transmembrane-electrostatically localized protons/cations charges (TELCs) theory, neural transmembrane potential including both resting and action potential is now well elucidated as the voltage contributed by the TELCs-membrane-anions capacitor biophysics in a neuron. Accordingly, neural transmembrane potential has an inverse relationship with TELCs surface density, which may represent a substantial progress in bettering the fundamental understanding of neuroscience. In this article, I will present a review on the latest development of the TELCs neural transmembrane potential theory and address Silverstein’s interesting arguments regarding the TELCs model that may constitute a complementary development to both the Hodgkin-Huxley classic cable theory …


Experimental Demonstration And Study Of Transmembrane-Electrostatically Localized Protons Prevail, James Weifu Lee Jan 2025

Experimental Demonstration And Study Of Transmembrane-Electrostatically Localized Protons Prevail, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

In this review in relation to some interesting arguments from Silverstein, it is now reaffirmed that the experimental demonstration of transmembrane-electrostatically localized protons (TELPs) was successfully accomplished through 1) using an aluminum film as a TELPs sensor in a biomimetic anode water-membrane-water cathode system, 2) analyzing the water-electrolysis current curve, and 3) measuring bulk liquid phase pH. Formation of induced TELPs was subsequently discovered in an anode water-membrane-water-membrane-water cathode system. The discovery of induced TELPs enabled clean experimental tests on the cation-TELPs exchange process by using sodium bicarbonate or potassium bicarbonate solution in the central liquid chamber. The sodium/TELPs exchange …


Validating A Novel Capability Of Assessing Pathways Of Animal Water Gain And Loss, Zachary T. Steele, Karen Caceres, Zachary A. David, Lisa M. Shollenberger, Alexander R. Gerson, Seth D. Newsome, John P. Whiteman Jan 2025

Validating A Novel Capability Of Assessing Pathways Of Animal Water Gain And Loss, Zachary T. Steele, Karen Caceres, Zachary A. David, Lisa M. Shollenberger, Alexander R. Gerson, Seth D. Newsome, John P. Whiteman

Biological Sciences Faculty Publications

Understanding variations in the routes by which wild animals gain and lose water is challenging, and common methods require longitudinal sampling, which can be prohibitive. However, a new approach uses Δ′¹⁷OBW (Δ′¹⁷O of animal body water), calculated from measurements of δ′¹⁷O and δ′¹⁸O in a single sample, as a natural tracer of water flux. Δ′¹⁷OBW is promising, but its relationship to organismal variables such as metabolic rate and water intake have not been validated. Here, we continuously measured oxygen influxes and effluxes of captive deer mice (Peromyscus maniculatus), and manipulated their water intake and metabolic rate. We used …


Swinging Lever Mechanism Of Myosin Directly Shown By Time-Resolved Cryo-Em, David P. Klebl, Sean N. Mcmillan, Cristina Risi, Eva Forgacs, Betty Virok, Jennifer L. Atherton, Sarah A. Harris, Michele Stofella, Donald A. Winkelmann, Frank Sobott, Vitold E. Galkin, Peter J. Knight, Stephen P. Muench, Charlotte A. Scarfi, Howard D. White Jan 2025

Swinging Lever Mechanism Of Myosin Directly Shown By Time-Resolved Cryo-Em, David P. Klebl, Sean N. Mcmillan, Cristina Risi, Eva Forgacs, Betty Virok, Jennifer L. Atherton, Sarah A. Harris, Michele Stofella, Donald A. Winkelmann, Frank Sobott, Vitold E. Galkin, Peter J. Knight, Stephen P. Muench, Charlotte A. Scarfi, Howard D. White

Department of Biomedical and Translational Sciences Faculty Publications

Myosins produce force and movement in cells through interactions with F-actin1. Generation of movement is thought to arise through actin-catalysed conversion of myosin from an ATP-generated primed (pre-powerstroke) state to a post-powerstroke state, accompanied by myosin lever swing2,3. However, the initial, primed actomyosin state has never been observed, and the mechanism by which actin catalyses myosin ATPase activity is unclear. Here, to address these issues, we performed time-resolved cryogenic electron microscopy (cryo-EM)4 of a myosin-5 mutant having slow hydrolysis product release5,6. Primed actomyosin was predominantly captured 10 ms after …


The Importance Of Solution Studies For The Structural Characterization Of The Enterovirus 5' Cloverleaf, Morgan G. Daniels, Meagan E. Werner, Xiaobing Zuo, Steven M. Pascal Jan 2025

The Importance Of Solution Studies For The Structural Characterization Of The Enterovirus 5' Cloverleaf, Morgan G. Daniels, Meagan E. Werner, Xiaobing Zuo, Steven M. Pascal

Chemistry & Biochemistry Faculty Publications

Enteroviruses initiate genomic replication via a highly conserved mechanism that is controlled by an RNA platform, also known as the 5' cloverleaf (5'CL). Here, we present a biophysical analysis of the 5'CL conformation of three enterovirus serotypes under various ionic conditions, utilizing CD spectroscopy, size-exclusion chromatography, and small-angle X-ray scattering. In general, a tendency toward a smaller monomeric hydrodynamic radius in the presence of salts was observed, but the exact structural signature of each 5'CL varied depending upon the serotype. Rhinovirus B14 (RVB14) exhibited at least two monomeric conformations and a low propensity for dimerization, while poliovirus 1 (PV1) showed …


The Anaerobic Rose Chamber (Arc): Novel Applications For Probing Clostridioides Difficile Dynamics, Tatiana Zvonareva Oct 2024

The Anaerobic Rose Chamber (Arc): Novel Applications For Probing Clostridioides Difficile Dynamics, Tatiana Zvonareva

Chemistry & Biochemistry Theses & Dissertations

Clostridioides difficile infection (CDI) is an urgent public health threat with a high rate of recurrence and limited treatment options. Caused by the anaerobic intestinal pathogen C. difficile, this disease affects up to 500,000 Americans annually. Despite progress in our understanding of CDI pathophysiology, the lack of effective and accessible experimental platforms compatible with obligate anaerobe physiology hinders the advancement of treatment therapy. The application of in vivo models has been indispensable in understanding CDI pathophysiology, probing the complexity of the host response to the microbe, and establishing treatment protocols, and it continues to be essential in preclinical testing. …


Intercellular Mitochondrial Transfer Contributes To Microenvironmental Fate Redirection Of Mammary Cancer Cells, Julie Sofie Bjerring Oct 2024

Intercellular Mitochondrial Transfer Contributes To Microenvironmental Fate Redirection Of Mammary Cancer Cells, Julie Sofie Bjerring

Biomedical Sciences Theses & Dissertations

The dynamic cellular microenvironment, made up of resident cells and various macromolecules, differs markedly across tissues in the body. The multidirectional signals that cells receive from this microenvironment, along with the signaling they send back, heavily influence their physiology and behavior. Recent important findings have further validated this notion as the mammary microenvironment has been shown to suppress tumor progression by redirecting cancer cells to adopt a normal mammary epithelial progenitor fate in vivo. However, the mechanism(s) driving changes in metabolic reprogramming and cancer fate redirection is understudied. The work presented in this dissertation focuses on exploring the impact of …


Use Of Cobalt(Iii) And Copper(Ii) Complexes With Thiosemicarbazone Ligands And Berberine Chloride As Anti-Cancer Agents Against Triple Negative Breast Cancer, Duaa Rashad Alajroush Jul 2024

Use Of Cobalt(Iii) And Copper(Ii) Complexes With Thiosemicarbazone Ligands And Berberine Chloride As Anti-Cancer Agents Against Triple Negative Breast Cancer, Duaa Rashad Alajroush

Chemistry & Biochemistry Theses & Dissertations

It is a worrying fact that chemotherapeutic options for treating triple negative breast cancer are limited in nature, including the use of inorganic pharmaceuticals such as cisplatin and its analogues. It has been reported that cisplatin has undesirable side effects when used as a chemotherapeutic drug. As such, there is a need to use non-platinum-containing complexes as chemotherapeutic agents. Based on that issue, it has been reported by our research group and others that cobalt- and copper-containing complexes have shown great potential in anti-cancer properties when compared to cisplatin. In this research project, the cytotoxic effects of the following complexes: …


Study Of Atypical Alarmone Synthesis In Clostridioides Difficile, Declan Nathaniel Butler Jul 2024

Study Of Atypical Alarmone Synthesis In Clostridioides Difficile, Declan Nathaniel Butler

Chemistry & Biochemistry Theses & Dissertations

Clostridioides difficile is a Gram-positive anaerobic bacterium that causes infections in humans that costs healthcare systems billions per year. C. difficile infection has high rates of recurrence due to multiple antibiotic resistance. When bacteria are in stressful environments, they produce hyperphosphorylated guanosine ribonucleotide signaling molecules called alarmones. The accumulation of alarmones activates the stringent response (SR), in which bacterial cells induce transcription of stress survival genes to delay growth and replication. The C. difficile SR is regulated by enzymatic activity of a bifunctional synthetase/hydrolase, RelA/SpoT homolog (RSH), and a monofunctional small alarmone synthetase (RelQ). Additionally, the SR is potentially regulated …


Exploring Cation Exchange: Unveiling Its Significance In Biochar And Bioenergetics Applications, Gyanendra Kharel Apr 2024

Exploring Cation Exchange: Unveiling Its Significance In Biochar And Bioenergetics Applications, Gyanendra Kharel

Chemistry & Biochemistry Theses & Dissertations

Cation exchange, a cornerstone of soil chemistry and nutrient cycling, is a fundamental chemical process that occurs in soils, sediments, membranes, and other solid materials. It involves the interchange of positively charged ions, or cations, between a solid matrix and a surrounding solution. This process is crucial in various natural and engineered systems, leading to a range of applications across different fields.

This dissertation presents an extensive investigation into the applications of cation exchange in the fields of biochar and bioenergetics, encompassing three distinct aims. The first aim concentrates on the surface oxygenation of biochar through ozonization, aiming to achieve …


Decreasing The Antibiotic Survival Of Multi-Drug Resistant Gram-Positive Organisms, Areej Malik Apr 2024

Decreasing The Antibiotic Survival Of Multi-Drug Resistant Gram-Positive Organisms, Areej Malik

Biomedical Sciences Theses & Dissertations

Biofilm production plays a crucial role in bacterial antibiotic tolerance and novel approaches are needed to combat it. The stringent response (SR), activated by nucleotide alarmones (pp)pGpp, is crucial for bacterial transcriptional reprogramming. In Clostridioides difficile, the SR is implicated in antibiotic survival, contributing to infection recurrence. Despite its known roles in sporulation and biofilm production in other bacterial species, the broader influence of the SR on C. difficile physiology remains undiscovered. This study deletes the C. difficile SR gene relQ, revealing the pivotal role of RelQ in regulating SR-dependent phenotypes in this organism. The absence of RelQ …


A Comparison Of In Vitro Studies Between Cobalt(Iii) And Copper(Ii) Complexes With Thiosemicarbazone Ligands To Treat Triple Negative Breast Cancer, Duaa R. Alajroush, Chloe B. Smith, Brittney F. Anderson, Ifeoluwa T. Oyeyemi, Stephen J. Beebe, Alvin A. Holder Mar 2024

A Comparison Of In Vitro Studies Between Cobalt(Iii) And Copper(Ii) Complexes With Thiosemicarbazone Ligands To Treat Triple Negative Breast Cancer, Duaa R. Alajroush, Chloe B. Smith, Brittney F. Anderson, Ifeoluwa T. Oyeyemi, Stephen J. Beebe, Alvin A. Holder

Undergraduate Research Symposium

Triple negative breast cancer (TNBC) is one of the most aggressive forms of breast cancer, and disproportionately affects African American women. TNBC cells lack the common hormone receptors that many pre-existing cancer treatments target. Fortunately, metal-based complexes with thiosemicarbazone ligands have gained significant attention for their potential as anti-cancer agents. Cobalt(III) complex ([Co(phen)2(MeATSC)](NO3)3•1.5H2O•C2H5OH]) and Copper(II) complex ([Cu(acetylethTSC)Cl]Cl•0.25C2H5OH) specifically have properties of high toxicity, which can contribute to decreased cancer cell activity. The effects of these complexes are currently being investigated on cancerous and non-cancerous breast cell lines. The cytotoxic effect of the cobalt(lll) complex and the copper(ll) complex was analyzed …