Biophysics Commons^™

Microorganisms In Extreme Environmental Conditions, Khanh Mai Nguyen

Graduate Theses and Dissertations

Organisms are known to be able to prosper under normal and extreme environmental conditions, which are classified as mesophile and extremophile, respectively. Extremophiles can thrive under a large array of conditions, from pressures, temperatures, salinity, and pH to a combination of them. For example, to survive on the ocean floor, marine biomass must have its biomolecular machinery adapted to the high pressures and high salinity environment. Moreover, around the hydrothermal vents, aside from pressure and salinity, the microbes that live there also need to adjust to the temperature as well as the pH level. Aside from high temperatures, researchers also …

Physics 422 Spring 2023 Syllabus, Ronald Koder

Open Educational Resources

Spring 2023 course syllabus for Physics 422, Biophysics, at the City College of New York

Physics 422 Spring 2023 Syllabus - Medical Physics, Ronald Koder

Open Educational Resources

This is the Spring 2023 syllabus for Physics 315, Medical Physics, at CCNY

Small Gtpase Regulated Intracellular Protein Trafficking In Endothelium, Caitlin Francis

Electronic Theses and Dissertations

Intracellular protein trafficking is the movement of membrane-bound organelles to and from requisite locations within the cell. Small GTPases are a critical component to the spatiotemporal accuracy of intracellular trafficking pathways as they determine the specificity and direction of organelle transport. There exists over 150 small GTPases categorized into 5 sub-families and are employed across all cell types. Despite their universal expression and relevance to cellular function, small GTPases remain incompletely understood across tissue types. In various instances, the trafficking pathway of a particular Rab in one cell type may belong to a completely disparate pathway in another cell type. …

Abstract 1858: Active And Allosteric Site Evolution Directs Ordered Water Use In Kinesin Catalysis, Micquel Downs, David Worthylake, Jessica Richard, Courtney Parke, Elizabeth Kim, Edward J. Wojcik, Sunyoung Kim

School of Graduate Studies Faculty Publications

2023 American Society for Biochemistry and Molecular Biology (ASBMB) Annual Meeting; March 25 - 28, 2023; Seattle, WA

Probing Amyloid-Beta Protein Structure And Dynamics With A Selective Antibody, Shikha Grover

Dissertations

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder. The AD brain is characterized by significant neuronal loss and accumulation of insoluble fibrillar amyloid-β protein (Aβ) plaques and tau protein neurofibrillary tangles in the brain. However, over the last decade, many studies have shown that the neurodegenerative effect of Aβ may in fact be caused by various soluble oligomeric forms as opposed to the insoluble fibrils. Furthermore, the data suggest that a pre-fibrillar aggregated form, termed protofibrils, mediates direct neurotoxicity, and triggers a robust neuroinflammatory response.

Antibodies targeting the various conformation of Aβ are important therapeutic agents to prevent the progression …

Contouring Quality Assurance Methodology Based On Multiple Geometric Features Against Deep Learning Auto-Segmentation, Jingwei Duan, Mark E. Bernard, James Castle, Xue Feng, Chi Wang, Mark C. Kenamond, Quan Chen

Markey Cancer Center Faculty Publications

Background: Contouring error is one of the top failure modes in radiation treatment. Multiple efforts have been made to develop tools to automatically detect segmentation errors.Deep learning-based auto-segmentation (DLAS) has been used as a baseline for flagging manual segmentation errors, but those efforts are limited to using only one or two contour comparison metrics.

Purpose: The purpose of this research is to develop an improved contouring quality assurance system to identify and flag manual contouring errors.

Methods and materials: DLAS contours were used as a reference to compare with manually segmented contours. A total of 27 geometric agreement metrics were …

Quantification Of Nuclear Dynamics During Epithelial Remodeling, Noah De Leeuw

Electronic Theses and Dissertations

The morphogenesis of developing tissues is contingent on an extensive array of rearrangements in cellular shape, position and identity at large and small scales. One commonly used process to reshape tissues is the cell intercalation-driven elongation of a tissue in a common axis, in which rows of epithelial cells undergo oriented intercalation in a directional fashion. In most models of intercalation, cells are treated as homogeneous objects directed in their shape changes by cortical forces localized along cell-cell interfaces or tricellular junctions. However, less attention has been paid to how inhomogeneities in mechanical resistance of their own internal structures affects …

Identifying The Role Of Phospholipase D1 And Phosphatidic Acid In Exocytosis, Broderick L. Bills

Electronic Theses and Dissertations

Exocytosis is an essential process for intercellular communication in eukaryotic cells. This process involves significant changes in membrane curvature, and lipids and curvature-sensing proteins can assist these processes. One protein in particular, phospholipase D1 (PLD1), and its product, the lipid phosphatidic acid (PA), are involved in multiple exocytic processes. However, PLD1 and PA’s role in this process has remained unclear. In this work, PLD1 and the production of PA were visualized during exocytosis, and PA localization to regions of membrane curvature was established. Together, these results support the hypothesis that PLD1 production of PA stabilizes negative curvature during membrane fusion. …

Detecting Linc Complex Mps3 And Nuclear Pore Complex Ndj1 Protein Interactions On Yeast Nuclear Membrane S Through Fluorescence Microscopy, Dean Boecher, Rebecca Adams

Science University Research Symposium (SURS)

Though cancer cells have been shown to have abnormal nuclear morphologies and responses to mechanical forces, the mechanisms of how mechanical stress is translated into cellular action and structural reorganization within the nuclear envelope are largely unexplored. The Linker of Nucleoskeleton and Cytoskeleton (LINC) complex is a transmembrane protein complex that connects the actin cytoskeleton to the lamin nucleoskeleton, enabling mechanical forces to be translated between the cytoplasm and the nucleus. In cells exposed to physical stress, nuclear pore complexes (NPCs) –which control the exchange of biochemical signals and macromolecules in and out of the nucleus through mRNA export –have …

Arginine-178 Is An Essential Residue For Itpa Function, Nicholas E. Burgis, Caitlin April, Kandise Vanwormer

Chemistry and Biochemistry Faculty Publications

The inosine triphosphate pyrophosphatase (ITPA) enzyme plays a critical cellular role by removing noncanonical nucleoside triphosphates from nucleotide pools. One of the first pathological ITPA mutants identified is R178C (rs746930990), which causes a fatal infantile encephalopathy, termed developmental and epileptic encephalopathy 35 (DEE 35). The accumulation of noncanonical nucleotides such as inosine triphosphate (ITP), is suspected to affect RNA and/or interfere with normal nucleotide function, leading to development of DEE 35. Molecular dynamics simulations have shown that the very rare R178C mutation does not significantly perturb the overall structure of the protein, but results in a high level of structural …

Impact Of Sample Conditions On Dna Phosphodiester Backbone Bi/Bii Conformational Equilibrium Dynamics, Autumn C. Pilarski

Graduate Theses/Dissertations

DNA damage, such as single base lesions and mismatches, is highly prevalent within cells. If these DNA damage events are not repaired, they could lead to mutations and thus disease and cancer. Intricate repair mechanisms are in place to fix these damage events, one such being Base Excision Repair (BER) and associated enzyme: Thymine DNA Glycosylase (TDG). The first step of this repair process, recognition of the lesion by TDG, is not well understood. The following thesis presents results to better understand the fundamental biophysical question of how a DNA lesion within a mismatch context is recognized in a million …

Molecular Mechanisms Of Wild-Type And Mutant Prion Formation, Daniel J. Walsh

Dartmouth College Ph.D Dissertations

Prion diseases are a class of infectious neurodegenerative disorders which affect humans and many other mammalian species. The causative agent is a unique pathogen known as a prion or PrPSc, a misfolded form of a host-encoded glycoprotein which replicates by templated conformational change. Distinct strains of prions with unique phenotypic and pathologic presentations appear to be encoded by subtle conformational changes within the misfolded protein. While the general manner of prion transmission is known, our detailed understanding of these mechanisms remains incomplete, limiting efforts for the discovery or design of therapeutic treatments for these fatal diseases. In vitro synthesis of …

Lipid Binding Properties Of Huntingtin As A Novel Therapeutic Target, Chathuranga Siriwardhana

Graduate Theses, Dissertations, and Problem Reports (ETD)

As protein aggregation is the defining hallmark of all amyloid diseases, a common therapeutic strategy is to develop molecules that inhibit aggregation. However, this approach has yielded limited success. Many amyloid proteins directly interact with lipid membranes. These interactions promote distinct aggregation pathways and often result in membrane damage leading to toxicity. As a result, directly targeting the ability of amyloids to bind lipid membranes represents a novel therapeutic strategy. As a proof of principle, the interaction between lipid membranes and mutant huntingtin protein (htt) aggregates was used to test this strategy. Mutant htt containing an expanded polygulatmine (polyQ) domain …

Exogenous Factors That Impact Huntingtin Aggregation, Adam Skeens

Graduate Theses, Dissertations, and Problem Reports (ETD)

While expansion of a polyglutamine (polyQ) domain is the immediate cause of huntingtin (htt) aggregation associated with Huntington’s Disease (HD), other cellular factors modify aggregation. These include interactions with cellular membranes, protein biding partners, molecular crowding, and proteinaceous seeds. Here, two important factors are biophysically characterized: 1) the interaction of htt with endomembranes and 2) proteinaceous seeds obtained from a variety of htt-derived peptides. In the first project, the aggregation of htt at bilayer interfaces and in the presence of divalent cations was investigated. A major cellular factor implicated in altered htt aggregation is the binding of lipids. Furthermore, the …

Analysis Of Biologically Effective Dose For Retroactive Yttrium-90 Trans-Arterial Radioembolization Treatment Optimization, Mj Lindsey

CMC Senior Theses

Trans-arterial radioembolization (TARE) is a protracted modality of radiation therapy where radionuclides labeled with Yttrium-90 (⁹⁰Y) are inserted inside a patient's hepatic artery to treat hepatocellular carcinoma (HCC). While TARE has been shown to be a clinically effective and safe treatment, there is little understanding of the radiobiological relationship between absorbed dose and tissue response, and thus there is no dosimetric standard for treatment planning. The Biologically Effective Dose (BED) formalism, derived from the Linear-Quadratic model of radiobiology, is used to weigh the absorbed dose by the time pattern of delivery. BED is a virtual dose that can …

Raw Data Files For The Manuscript 'Elastin Recoil Is Driven By The Hydrophobic Effect', Nour M. Jamhawi, Ronald Koder, Richard J. Wittebort

Publications and Research

These are the raw data files associated with the manuscript 'Elastin Recoil is Driven by the Hydrophobic Effect' by Nour M. Jamhawi, Ronald L. Koder, and Richard J. Wittebort

A Biophysical Approach To Modeling Elevational Range Shifts In Colorado Mammal Communities, Ryan T. Mahar

Graduate Student Theses, Dissertations, & Professional Papers

Species geographic ranges are shifting in the face of contemporary climate warming, and documenting range shifts is crucial to our understanding of the underlying drivers mediating movement in geographic range limits. Studies on elevational range shifts with climate change are beginning to accrue within the literature, though observed shifts are idiosyncratic and difficult to predict. Some species may respond to warming temperatures by shifting their range limits upslope, where temperatures are cooler owing to the adiabatic lapse rate. However, species may also respond to warming temperatures in an elevation-dependent manner: if changes in snow depth expose overwintering organisms to colder …

Exploring The Membrane Protein And Peptide Interactions Of Mitochondrial And Bacterial Lipid Systems, George Saudan

Theses and Dissertations (Comprehensive)

This study aims to expand the understanding of interactions between membrane lipids and proteins, and relate it to their biological functions in two experimental systems. The first system focuses on the interaction and conformation of a membrane protein Uncoupling Protein 4 (UCP4) in mitochondrial inner membrane lipids, in the absence and presence of cardiolipin; a lipid specific to mitochondrial inner membranes. The second system considers the interaction and conformation of a cell penetrating peptide, Penetratin, which can interact with both mammalian and bacterial cells. A N- and C-termini protected form of this 16-meric peptide (Pen2) was used to explore its …

Application Of Computational Biophysics Techniques To Characterize Cell Membrane-Associated Events, Kyle Billings

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cell membranes are crowded environments which can modulate protein structure-function relationships through interaction with lipids, other proteins, carbohydrate structures and so on. This work focuses the impact of the membrane environment on two varieties of peptides: Microbial rhodopsin proteins, and cyclic peptides.

Life on Earth is dependent on the ability of plants and microbes to harness sunlight for energy production. Their ability to transform light into carbohydrates requires tailor-made machinery, and for a wealth of microorganisms, microbial rhodopsin proteins (MR) are critical for maintaining the concentration gradients used to produce the energy molecule Adenosine triphosphate (ATP). The central retinal molecule …