Molecular Biology Commons^™

Characterizing 4,4’-Methylene Diphenyl Diisocyanate Exposure In Primary Human Epidermal Keratinocytes: A Multi-Omics Approach, Brandon F. Law

Graduate Theses, Dissertations, and Problem Reports (ETD)

Exploring the routes of exposure and biological fate of 4,4’-methylene diphenyl diisocyanate (MDI) has been a challenge for many years. Occupational exposure to MDI can result in the development of occupational asthma (MDI-OA) which results in loss of productivity, large economic costs, and costs to the individual worker. Initially, it was thought that respiratory exposure to MDI was the most likely route leading to MDI-OA. Industries utilizing MDI have been successful at controlling airborne concentrations according to industrial hygiene assessment and newly diagnosed cases of MDI-OA decreased and plateaued. New research suggests that dermal exposures to MDI may explain this …

Personalized Molecular Therapies For Advanced Non-Small Cell Lung Cancer: Overcoming Heterogeneity To Optimize Treatment Response And Clinical Outcomes, Zuan-Fu Lim

Graduate Theses, Dissertations, and Problem Reports (ETD)

Lung cancer remains one of the deadliest cancers. Novel, paradigm shifting treatments including immunotherapy and targeted therapies have recently been developed to cull the deadly effects of lung cancer, but many challenges remain. There remains a significant unmet need to accurately predict and optimally select for patients who will respond to immune checkpoint inhibitors (ICI) treatment. In Chapter 2 of this dissertation, we investigated a novel live single cell cytokine profiling lab-on-chip platform, IsoLight, using peripheral CD4+ and CD8+ T-cells for ICI biomarker development. A total of 55,175 single T-lymphocytes were analyzed in this proof-of-concept study. We found that an …

The Function Of Protein Glutamylation In Vision, Rawaa Aljammal

Graduate Theses, Dissertations, and Problem Reports (ETD)

Posttranslational glutamylation of protein has emerged as a novel candidate for cellular integrity. In a dynamic process, Tubulin Tyrosine Ligase Like proteins (TTLLs) introduce glutamate groups to their substrates, while Cytosolic Carboxypeptidases members (CCP1-CCP6) remove these glutamate groups. The outcome of this interplay is a wide range of substrates; each is glutamylated to a level crucial for its function.

Protein glutamylation is particularly abundant in neurons and in the axoneme of cilia and flagella. This distribution, along with the correlation between imbalanced glutamylation levels and compromised cellular functions, underscores the significance of protein glutamylation in maintaining cellular viability. However, the …

Exploring 3d Genome Interaction And Epigenetic Regulation Via Swi/Snf Complex And Deep Learning Models, Ruoyun Wang

Dartmouth College Ph.D Dissertations

The three-dimensional organization of the genome is fundamental in regulating gene expression and maintaining cellular function. This organization's complexities, influenced by epigenetic marks and chromatin remodeling complexes, are crucial for understanding genomic regulation. Among these, the SWI/SNF complexes are key, facilitating chromatin accessibility and regulating gene activity across cell types. The first part of my dissertation focuses on SWI/SNF complexes, exploring their role in chromatin remodeling and their impact on 3D genome architecture. Utilizing next-generation sequencing (NGS) techniques, this section investigates the interplay between these complexes and chromatin structure. During my research on the SWI/SNF complex, I was intrigued by …

A Multimolecular Perspective On The Success Of Wolf Recovery And Relocation, Samuel D. Hervey

Dissertations, Master's Theses and Master's Reports

With global biodiversity in decline and many species isolated in fragmented habitats, conservation efforts increasingly rely on natural recolonization and translocation to restore ecosystems. These strategies face challenges such as genetic erosion and habitat limitations, highlighting the need for effective monitoring practices. This research assesses the success of wolf recovery initiatives by examining long-term genetic and genomic health using both traditional and advanced molecular methods. First, we investigated the genetic health of 19 gray wolves (Canis lupus) relocated to Isle Royale National Park to restore ecosystem balance. Initial genetic assessments with microsatellites found that these wolves had genetic diversity metrics …

Inactive Metallopeptidase Homologs: The Secret Lives Of Pseudopeptidases, Peter Lyons

Faculty Publications

Inactive enzyme homologs, or pseudoenzymes, are proteins, found within most enzyme families, that are incapable of performing catalysis. Rather than catalysis, they are involved in protein-protein interactions, sometimes regulating the activity of their active enzyme cousins, or scaffolding protein complexes. Pseudoenzymes found within metallopeptidase families likewise perform these functions. Pseudoenzymes within the M14 carboxypeptidase family interact with collagens within the extracellular space, while pseudopeptidase members of the M12 "a disintegrin and metalloprotease" (ADAM) family either discard their pseudopeptidase domains as unnecessary for their roles in sperm maturation or utilize surface loops to enable assembly of key complexes at neuronal synapses. …

Structural Basis For Dna Proofreading, Gina Buchel, Ashok Nayak, Karl Herbine, Azadeh Sarfallah, Viktoriia Sokolova, Angelica Zamudio-Ochoa, Dmitry Temiakov

Department of Biochemistry and Molecular Biology Faculty Papers

DNA polymerase (DNAP) can correct errors in DNA during replication by proofreading, a process critical for cell viability. However, the mechanism by which an erroneously incorporated base translocates from the polymerase to the exonuclease site and the corrected DNA terminus returns has remained elusive. Here, we present an ensemble of nine high-resolution structures representing human mitochondrial DNA polymerase Gamma, Polγ, captured during consecutive proofreading steps. The structures reveal key events, including mismatched base recognition, its dissociation from the polymerase site, forward translocation of DNAP, alterations in DNA trajectory, repositioning and refolding of elements for primer separation, DNAP backtracking, and displacement …

Characterization Of Trafficking And Metabolic Functions Of The Endocytic Regulator Ehd1 In Ewing Sarcoma, Sukanya Chakraborty

Theses & Dissertations

Ewing sarcoma (EWS) is the second most common bone malignancy in children and adolescents. Despite improvement in survival due to advances in multimodality treatment strategies, patients with metastatic or recurrent disease have very poor outcomes. Overexpression of the EPS15 Homology Domain containing 1 (EHD1) protein has been linked to tumorigenesis but whether its core function as a regulator of intracellular traffic of cell surface receptors plays a role in oncogenesis remains unknown.

Studies presented in this dissertation establish that EHD1 overexpression is a feature of nearly 90% EWS patient tumors with high EHD1 expression specifying shorter patient survival. ShRNA-knockdown and …

Deep Learning Image Analysis To Isolate And Characterize Different Stages Of S-Phase In Human Cells, Kevin A. Boyd, Rudranil Mitra, John Santerre, Christopher L. Sansam

SMU Data Science Review

Abstract. This research used deep learning for image analysis by isolating and characterizing distinct DNA replication patterns in human cells. By leveraging high-resolution microscopy images of multiple cells stained with 5-Ethynyl-2′-deoxyuridine (EdU), a replication marker, this analysis utilized Convolutional Neural Networks (CNNs) to perform image segmentation and to provide robust and reliable classification results. First multiple cells in a field of focus were identified using a pretrained CNN called Cellpose. After identifying the location of each cell in the image a python script was created to crop out each cell into individual .tif files. After careful annotation, a CNN was …

Using In Silico Tools To Analyze The 5ʹ Untranslated Regions Of The Alcohol Dehydrogenase Gene From Arabidopsis Thaliana And Omega Sequence, Reza Mohammadhassan, Tina Asadishad

Makara Journal of Science

The 5ʹ ends of protein-encoding genes contain 5ʹ untranslated regions (5ʹUTRs), which can effectively participate in regulating gene expression. The 5ʹUTRs of Arabidospis thaliana–derived alcohol dehydrogenase gene (AtADH) and omega (Ω) sequence from tobacco mosaic virus (TMV) are the most effective enhancers in biotechnology. In this study, bioinformatics techniques were employed to analyze the characteristics of the above sequences. After 5ʹUTR sequence collection, the inner ribosome entrance sites; small RNA (sRNA) target sequences; nucleotide contents; and upstream start and stop codons, ORFs, and coding DNA sequences of the Ω sequence and AtADH 5ʹUTR were identified. Moreover, the …

The Potential Of Endophytic Bacteria As The Biocontrol Agents Of Fusarium Proliferatum, Rima Ernia, Nisa Rachmania Mubarik, Lisdar Idwan Sudirman

Makara Journal of Science

Fusarium proliferatum decreases the productivity of shallot (Allium cepa L.). Endophytic bacteria are potential biocontrol agents in controlling the growth of F. proliferatum. This study aimed to select and characterize endophytic bacteria producing bioactive compounds that inhibit the growth of F. proliferatum. The endophytic bacteria used were isolated from the roots, stems, leaves, and soil of shallot plants from healthy and diseased shallot farming fields. The endophytic bacteria were selected using the dual culture method and extracted using ethyl acetate solvent. The results of the 16S rRNA identification suggested that isolate ABP5.2 is similar to Pseudomonas …

Increased Coding Potential Of Bovine Herpesvirus 1, Victoria Jefferson

Theses and Dissertations

Bovine respiratory disease (BRD) costs the cattle industry millions of dollars in costs in treatment and loss every year in the United States. A significant pathogen often contributes to BRD is Bovine Herpesvirus 1 (BoHV-1), a double stranded DNA virus with the ability to establish latency in the trigeminal ganglia and neurons. Primary infection with BoHV-1 results in immunosuppression that increases the risk of secondary bacterial infection and pneumonia. Because herpesviruses infect their hosts for life and can be reactivated in times of stress, BoHV-1 can present a recurring risk of BRD. The following research aims to expand the knowledge …

Diaryl Oxazoles As Cleavable Linkers For Drug Discovery Platforms, Elizabeth Taggart

Honors Theses

Within the field of medicine and pharmacology, discovering small molecule or biologic based molecules with therapeutic potential is a difficult task. Current methods involve individually screening hundreds of compounds on a potential target biomolecule, and recent technologies have explored peptide encoded libraries (PELs) as a means of making this screening process more high-throughput. These libraries produce a large number of small molecule drug candidates each conjugated to a unique peptide fragment, functioning as a barcode. Analysis of PELs requires the capture of hit small molecules and the subsequent release of their peptide tags; however, current approaches are limited in their …

Extraction Of Transcriptional Regulators For The Polyhydroxyalkanoate Depolymerase Gene From Streptomyces Nymphaeiformis, Kara B. Eppard, Stephen F. Baron

Honors Projects

Plastic waste has become an increasingly prevalent environmental pollutant. This problem is exacerbated by the inability of plastic to degrade under most natural conditions. In contrast, polyhydroxyalkanoates (PHAs) are biologically produced, plastic-like polymers that can be broken down and metabolized by bacteria. The bacterium Streptomyces nymphaeiformis can degrade the PHA, polyhydroxybutrate (PHB), using an extracellular PHB depolymerase, which is encoded by the phaZ gene. PHB depolymerase is synthesized only in the presence of PHB or its monomer, but not glucose, suggesting that transcription of phaZ is regulated, presumably by transcriptional regulatory proteins that bind to its promoter region. The DNA …

Biochemical Analyses Of Udgx-A Crosslinking Uracil-Dna Glycosylase, Chuan Liang

All Dissertations

DNA base damage is common due to exposure to various endogenous and exogenous factors. To repair the base lesions, such as uracil from cytosine deamination, enzymes from the uracil-DNA glycosylase (UDG) superfamily are critical, which can recognize the damaged base and initiate the base excision repair (BER) pathway. There used to be six families of proteins identified in the UDG superfamily until a new member, UDGX, was found in Mycobacterium smegmatis, which is a unique DNA-crosslinking UDG. In this dissertation work, a series of biochemical analyses of the newly found UDGX are performed, including the analyses of structures, functions, …

A Novel Role Of Tgfbi In Macrophage Polarization And Macrophage-Induced Pancreatic Cancer Growth And Therapeutic Resistance, Jing Zhou, Nan Lyu, Qiongling Wanga, Ming Yang, Eric T. Kimchi, Kun Chenge, Trupti Joshi, Adama R. Tukulif, Kevin F. Staveley-O’Carroll, Guangfu Li

Biomedical Sciences

Tumor-associated macrophages (TAMs), as a major and essential component of tumor microenvironment (TME), play a critical role in orchestrating pancreatic cancer (PaC) tumorigenesis from initiation to angiogenesis, growth, and systemic dissemination, as well as immunosuppression and resistance to chemotherapy and immunotherapy; however, the critical intrinsic factors responsible for TAMs reprograming and function remain to be identified. By performing single-cell RNA sequencing, transforming growth factor-beta-induced protein (TGFBI) was identified as TAM-producing factor in murine PaC tumors. TAMs express TGFBI in human PaC and TGFBI expression is positively related with human PaC growth. By inducing TGFBI loss-of-function in macrophage (MΦs) in vitro …

Identification Of Genes Conferring Resistance To 2-Amino-3-Methylimidazo [4,5-F] Quinoline Genotoxicity In Budding Yeast Using High-Throughput And Targeted Approaches, Michael J. Dolan

Legacy Theses & Dissertations (2009 - 2024)

Heterocyclic aromatic amines (HAAs) are potent carcinogenic agents found in charred read meat and cigarette smoke. We hypothesize that HAAs may contribute to red meat being a risk factor for colorectal cancer (CRC). At present, few eukaryotic genes conferring resistance to HAAs have been identified. In this research, the genome of Saccharomyces cerevisiae (budding yeast) was profiled using next-generation sequencing to identify genes conferring resistance to one such HAA, 2-amino-3-methylimidazo[4,5-f] quinoline (IQ).CYP1A2 and NAT2 activate IQ to become a mutagenic nitrenium compound. Deletion libraries expressing human CYP1A2 and NAT2 or no human genes were exposed to either 400 or 800 …

Identification And Characterization Of Geotrichum Candidum Isolates From Peach With Reduced Sensitivity To Propiconazole, Sara Price

All Theses

Geotrichum candidum Link (1809) is a yeast-like fungus that causes sour rot of stone fruits, including peach (Prunus persica). The disease caused damage between 2021 and 2023 to the peach crop kept in cold storage at a commercial farm in South Carolina despite preharvest and postharvest applications of fungicides. Isolates from 41 symptomatic fruit, from a South Carolina (SC) commercial packing house, as well as other isolates obtained from South Carolina were identified to be G. candidum based on species-specific PCR amplifications of the β tubulin gene. Commonly used postharvest fungicide fludioxonil had no effect on G. candidum mycelial growth …

Cell Aggregation Activates Small Gtpase Rac1 And Induces Cd44 Cleavage By Maintaining Lipid Raft Integrity, Dong Li, Younhee Park, Hami Hemati, Xia Liu

Markey Cancer Center Faculty Publications

Lipid rafts are highly ordered membrane domains that are enriched in cholesterol and glycosphingolipids and serve as major platforms for signal transduction. Cell detachment from the extracellular matrix (ECM) triggers lipid raft disruption and anoikis, which is a barrier for cancer cells to metastasize. Compared to single circulating tumor cells (CTCs), our recent studies have demonstrated that CD44-mediatd cell aggregation enhances the stemness, survival and metastatic ability of aggregated cells. Here, we investigated whether and how lipid rafts are involved in CD44-mediated cell aggregation. We found that cell detachment, which mimics the condition when tumor cells detach from the ECM …

Deficiency Of Acute-Phase Serum Amyloid A Exacerbates Sepsis-Induced Mortality And Lung Injury In Mice, Ailing Ji, Andrea C. Trumbauer, Victoria P. Noffsinger, Luke W. Meredith, Brittany Dong, Qian Wang, Ling Guo, Xiangan Li, Frederick C. De Beer, Nancy R. Webb, Lisa R. Tannock, Marlene E. Starr, Christopher M. Waters, Preetha Shridas

Saha Cardiovascular Research Center Faculty Publications

Serum amyloid A (SAA) is a family of proteins, the plasma levels of which may increase >1000-fold in acute inflammatory states. We investigated the role of SAA in sepsis using mice deficient in all three acute-phase SAA isoforms (SAA-TKO). SAA deficiency significantly increased mortality rates in the three experimental sepsis mouse models: cecal ligation and puncture (CLP), cecal slurry (CS) injection, and lipopolysaccharide (LPS) treatments. SAA-TKO mice had exacerbated lung pathology compared to wild-type (WT) mice after CLP. A bulk RNA sequencing performed on lung tissues excised 24 h after CLP indicated significant enrichment in the expression of genes associated …