Bioinformatics Commons^™

The Hepatic Immunological Pattern Shaped By Dominant-Subdominant Cellular Interactions Creates A Collective Function Beyond The Function Of Each Cellular Constituent To Orchestrate Progression Of Hepatocellular Carcinoma, Nicholas J. Koelsch

Theses and Dissertations

Abundance of data on the role of inflammatory immune responses in the progression or inhibition of hepatocellular carcinoma (HCC) has failed to offer a curative immunotherapy for HCC. This is largely because of taking reductionist approaches and missing the collective function of the hepatic immune system by focusing on specific immune cell types. To this end, we propose that focusing on the dominant-subdominant patterns of the immune cells would allow understanding of the mechanism by which a collective immune function emerges. To identify the collective immune function through a systems immunology perspective, we performed high-throughput analysis of snRNAseq data collected …

Association Of Interpersonal Trauma And Polygenic Risk Scores With Depressive Symptoms In College Students, Rowan K. O'Hara

Theses and Dissertations

Major depression is considered a complex trait influenced by both polygenic risk factors and environmental exposures, such as childhood trauma. This study applied statistical genetic methods to calculate aggregate genetic risk for major depression to predict depressive symptoms scores in a college student sample. Data were from the Spit for Science (S4S) study in which college students from a large urban university self-reported interpersonal trauma (IPT) exposure prior to college and depressive symptoms from the past month (N = 7502; ancestry group: 20% African [AFR], 12% Admixed Americas [AMR], 10% East Asian [EAS], 49% European [EUR], 8% South Asian [SAS]). …

Genomic Comparison Of Dba/2j And C57bl/6j Strains Of Mus Musculus And Best Practice Of Genome Alignment For Bioinformatics Analyses, Dustin J. Zeliff

Theses and Dissertations

Alcohol use disorder is known to have significant genetic components that contribute to an individual’s susceptibility to the disease. Mouse models are commonly used to study the mechanisms underlying alcohol use disorder, with C57BL/6J (B6) and DBA/2J (D2) being two of the more prominently used inbred strains. Research in the Miles Laboratory has used these two strains, and genetic panels of mice derived from them, to identify potential genes associated with variance in ethanol-related behaviors using quantitative trait loci (QTL) analysis. For example, Ninein (Nin) was identified as a potential candidate gene for the anxiolytic effects of ethanol, discovered because …

A Standardized Pipeline For Isolation And Assembly Of Genomes From Symbiotic Bacteria In Whole Louse Genomic Sequence Data., Mohammad Mikail I. Bala

Theses and Dissertations

Many insects are known to harbour intracellular and heritable bacteria (endosymbionts), which provide their hosts with adaptive traits. Whole insect gDNA shotgun sequencing projects often sequence the genome of endosymbiont, in addition to the insect’s genome. There are approximately 600 whole genome shotgun libraries from insects available on the public repository (NCBI), which can be mined to obtain endosymbiont genomes. The assembly and annotation of endosymbiont genomes can contribute towards the exploration of their role as obligate symbiotic partners. However, de novo assembly of an endosymbiont genome, continues to be challenging, when the host and/or enteric bacterial gDNA is present …

Structure-Based Drug Discovery And Development Of Protein Structure Prediction Tools Using An Empirical Force Field, Noah B. Herrington

Theses and Dissertations

Traditional drug discovery has rapidly accelerated thanks to development of computational molecular modeling. The crucial component that these computational studies hinge upon is having a well-defined, and energetically favorable structure. Structures of proteins and ligands that meet these criteria are important for accurately simulating models used to study drug binding. To demonstrate the role of accurate structure simulation in the study of these events, this thesis presents, first, a story examining the problem of accurate structure modeling of ionizable residues within protein structures, specifically aspartic acid, glutamic acid, and histidine. I present our method, which uses the HINT force field …

Bioinformatic Pipeline For Determining Terminal Repeats In The Human Cytomegalovirus Genome Assembled With Pacbio Long Read Sequences, Ahmed Al Qaffas

Theses and Dissertations

Human Cytomegalovirus (HCMV) is a member of the betaherpesvirinae subfamily of the Herpesvirus family. HCMV infection is common among adults worldwide, with an estimated seroprevalence of 66 to 95%, depending on the geographic region (Zuhair et al., 2019). Although most of the virus genomic content has been studied extensively, the terminal repeating region sequences remain understudied. Two main challenges hindered the study of the region: a) limitations of sequencing technologies; and b) misassembly of the repeats due to its complex nature. Here I show a novel bioinformatics pipeline that takes advantage of PacBio's long reads to resolve the challenges mentioned …

Protein Structure And Interaction: The Role Of Aromatic Residues In Protein Structure And Interactions Between Pyridoxine 5'-Phosphate Oxidase/Dopa Decarboxylase, Mohammed H. Al Mughram

Theses and Dissertations

Naturally developed proteins are capable of carrying out a wide variety of molecular functions due to their highly precise three-dimensional structures, which are determined by their genetically encoded sequences of amino acids. A thorough knowledge of protein structures and interactions at the atomic level will enable researchers to get a deep foundational understanding of the molecular interactions and enzymatic processes required for cells, resulting in more effective therapeutic interventions. This dissertation intends to use structural knowledge from solved protein structures for two distinct objectives.

In the first project, we conducted a bioinformatics structural analysis of experimental protein structures using our …

Evaluating Population Genetic Structure And Potential Genomic Signals Of Natural Selection In A Migratory Songbird (Protonotaria Citrea), Tyler A. Hohenstein

Theses and Dissertations

In this study I attempted to further resolve the population genetic structure in the Prothonotary Warbler (Protonotaria citrea), and conducted an outlier SNP analysis and exploratory gene ontology analysis to investigate potential ongoing natural selection in the species. This analysis of population structure confirms previous work by DeSaix et al. (2019), where weak population structure was observed between eastern sites along the Atlantic Coastal Plain, and western sites in the Mississippi Alluvial Valley, possibly due to a genetic discontinuity across the Appalachian Mountains. I conducted two forms of outlier SNP analyses, a principal component analysis (PCA)-based approach to identify SNPs …

Computational Analysis Of Drug Targets And Prediction Of Protein-Compound Interactions, Sina Ghadermarzi

Theses and Dissertations

Computational prediction of compound-protein interactions generated a substantial amount of interest in the recent years owing to the importance of the knowledge of these interaction for drug discovery and drug repurposing efforts. Research suggests that the currently known drug targets constitute only a fraction of a complete set of drug targets, limiting our ability to identify suitable targets to develop new drugs or to repurpose current drugs for new diseases. These efforts are further thwarted by our limited knowledge of protein-drug (and more generally protein-compound) interactions, where only a subset of drug targets is typically known for the currently used …

Estimating Weighted Panel Sizes For Primary Care Providers: An Assessment Of Clustering And Novel Methods Of Panel Size Estimation On Electronic Medical Records, Martin A. Lavallee

Theses and Dissertations

Primary Care is on the frontlines of healthcare, thus they see the most diverse set of patients. In order to achieve high functioning primary care, a practice must establish empanelment, the pairing of patients to providers. Enumeration of empanelment, or estimating panel sizes, helps ensure that the demands of the patients demand the supply of providers and optimize the balance of primary care resources to improve quality of care. Further we can adjust panel sizes by using patient-level data on healthcare utilization and complexity extracted from the electronic medial record to determine the amount of care or burden of work …

Identifying The Human Homologs Of Yeast Rab Proteins Ypt10 & Ypt11 And A Global-Scale Louse Endosymbiont Genome Variation, Nathaniel P. Smith

Theses and Dissertations

Amyotrophic lateral sclerosis (ALS) is a late-onset fatal neurodegenerative disease that causes loss of upper and/or lower motor neurons, and currently has no treatment or cure available. Over 90% of cases occur spontaneously with unknown causes, highlighting the complexity of the disease, and only 10% of cases are linked to heritable genetic mutations. Numerous ALS-linked genes are conserved through evolution, and model organisms may therefore provide opportunities to understand disease pathology at a molecular or cellular level, proving instrumental in identifying therapeutic targets. ALS subtype 8 (ALS8) is caused by an autosomal dominant P56S mutation in the VAPB gene that …

Computational Analysis And Prediction Of Intrinsic Disorder And Intrinsic Disorder Functions In Proteins, Akila I. Katuwawala

Theses and Dissertations

COMPUTATIONAL ANALYSIS AND PREDICTION OF INTRINSIC DISORDER AND INTRINSIC DISORDER FUNCTIONS IN PROTEINS

By Akila Imesha Katuwawala

A dissertation submitted in partial fulfillment of the requirements for the degree of Engineering, Doctor of Philosophy with a concentration in Computer Science at Virginia Commonwealth University.

Virginia Commonwealth University, 2021

Director: Lukasz Kurgan, Professor, Department of Computer Science

Proteins, as a fundamental class of biomolecules, have been studied from various perspectives over the past two centuries. The traditional notion is that proteins require fixed and stable three-dimensional structures to carry out biological functions. However, there is mounting evidence regarding a “special” class …

Interspecific Gene Flow Potentiates Adaptive Evolution In A Hybrid Zone Formed Between Pinus Strobiformis And Pinus Flexilis, Mitra Menon

Theses and Dissertations

Species range margins are often characterised by high degrees of habitat fragmentation resulting in low genetic diversity and higher gene flow from populations at the core of the species range. Interspecific gene flow from a closely related species with abutting range margins can increase standing genetic diversity and generate novel allelic combinations thereby alleviating limits to adaptive evolution in range margin populations. Hybridization driven interspecific gene flow has played a key role in the demographic history of several conifer due to their life history characteristics such as weak crossability barriers and long generation times. Nevertheless, demonstrating whether introgression is adaptive …

Ndrg1 And Myelin-Related Disease: Alcoholism And Chemotherapy-Induced Neuropathy, Guy Harris

Theses and Dissertations

Alcohol use disorder (AUD) is a prevalent neuropsychiatric disease with profound health, social, and economic consequences. With an estimated 50% heritability, identifying genes that engender risk and contribute to the underlying neurobiological mechanisms represents an important first step in developing effective treatments. Gene expression studies are an important source of candidate genes for studying AUD, providing windows into the molecular machinery engaged by the brain in response to ethanol. Our laboratory has implicated N-myc down-regulated gene 1 (Ndrg1) as a potential candidate gene that modulates ethanol-induced changes in myelin-related gene expression and acute sensitivity to ethanol. Analysis of …

Methods For Joint Normalization And Comparison Of Hi-C Data, John C. Stansfield

Theses and Dissertations

The development of chromatin conformation capture technology has opened new avenues of study into the 3D structure and function of the genome. Chromatin structure is known to influence gene regulation, and differences in structure are now emerging as a mechanism of regulation between, e.g., cell differentiation and disease vs. normal states. Hi-C sequencing technology now provides a way to study the 3D interactions of the chromatin over the whole genome. However, like all sequencing technologies, Hi-C suffers from several forms of bias stemming from both the technology and the DNA sequence itself. Several normalization methods have been developed for normalizing …

Evaluating Predixcan’S Ability To Predict Differential Expression Between Alcoholics And Non-Alcoholics, John E. Drake Jr

Theses and Dissertations

PrediXcan is a recent software for the imputation of gene expression from genotype data alone. Using an overlapping set of transcriptome datasets from postmortem brain tissues of donors with alcohol use disorder and neurotypical controls, which were generated by two different platforms (e.g., Arraystar and Affymetrix), and an additional unrelated transcriptome dataset from lung tissue, we sought to evaluate PrediXcan’s ability to impute gene expression and identify differentially expressed genes. From the Arraystar platform, 1.3% of matched genes between the measured and imputed expression had a Pearson correlation ≥ 0.5. Our attempt to replicate this finding using the expression data …

Discovering Driver Mutations In Biological Data, Yahya Bokhari

Theses and Dissertations

Background

Somatic mutations accumulate in human cells throughout life. Some may have no adverse consequences, but some of them may lead to cancer. A cancer genome is typically unstable, and thus more mutations can accumulate in the DNA of cancer cells. An ongoing problem is to figure out which mutations are drivers - play a role in oncogenesis, and which are passengers - do not play a role. One way of addressing this question is through inspection of somatic mutations in DNA of cancer samples from a cohort of patients and detection of patterns that differentiate driver from passenger mutations. …

High-Throughput Prediction And Analysis Of Drug-Protein Interactions In The Druggable Human Proteome, Chen Wang

Theses and Dissertations

Drugs exert their (therapeutic) effects via molecular-level interactions with proteins and other biomolecules. Computational prediction of drug-protein interactions plays a significant role in the effort to improve our current and limited knowledge of these interactions. The use of the putative drug-protein interactions could facilitate the discovery of novel applications of drugs, assist in cataloging their targets, and help to explain the details of medicinal efficacy and side-effects of drugs. We investigate current studies related to the computational prediction of drug-protein interactions and categorize them into protein structure-based and similarity-based methods. We evaluate three representative structure-based predictors and develop a Protein-Drug …

Hub Proteins, Paralogs, And Unknown Proteins In Bacterial Interaction Networks, Neha Sakhawalkar

Theses and Dissertations

Proteins are the functional units of cells. However, a major portion of the proteome does not have a known functional annotation. This dissertation explores protein -protein interactions, involving these uncharacterized or unknown function proteins. Initially, protein – protein interactions were tested and analyzed for paralogous proteins in Escherichia coli. To expand this concept further and to get an overview, protein – protein interactions were analyzed using ‘comparative interactomics’ for four pathogenic bacterial species including Escherichia coli, Yersinia pestis, Vibrio cholerae and Staphylococcus aureus. This approach was used to study unknown function protein pairs as well as to …

In Search Of A Function For An Uncharacterized Conserved Protein In Streptococcus Sanguinis Sk36, Ayana Scott-Elliston

Theses and Dissertations

With the number of fully sequenced bacterial genomes increasing in the past 7 years, it has been discovered that a large percentage of the putative protein coding genes have no known function. This lack of knowledge leaves scientists with an incomplete understanding of bacteria. In this study, conserved hypothetical protein mutants from Streptococcus sanguinis SK36 were screened on solid media with various environmental conditions. From these screens, the candidate protein, SSA_2372, displayed a sensitivity to acidic conditions. Its homolog in Bacillus subtilis 168, BSU00030, also displayed a sensitivity to pH conditions at its acid tolerance extremes unlike its other homolog …

A Systems Biology Approach For Predicting Essential Genes And Deciphering Their Dynamics Under Stress In Streptococcus Sanguinis, Fadi El-Rami

Theses and Dissertations

Infectious diseases are the top leading cause of death worldwide. Identifying essential genes, genes indispensable for survival, has been proven indispensable in defining new therapeutic targets against pathogens, major elements of the minimal set genome to be harnessed in synthetic biology, and determinants of evolutionary relationships of phylogenetically distant species. Thus, essentiality studies promise valuable revenues that can decipher much of biological complexities.

Taking advantage of the available microbial sequences and the essentiality studies conducted in various microbial models, we proposed a framework for the prediction of essential genes based on our experimentally verified knowledge of the pathways involved in …

Power Analysis In Applied Linear Regression For Cell Type-Specific Differential Expression Detection, Edmund Glass

Theses and Dissertations

The goal of many human disease-oriented studies is to detect molecular mechanisms different between healthy controls and patients. Yet, commonly used gene expression measurements from any tissues suffer from variability of cell composition. This variability hinders the detection of differentially expressed genes and is often ignored. However, this variability may actually be advantageous, as heterogeneous gene expression measurements coupled with cell counts may provide deeper insights into the gene expression differences on the cell type-specific level. Published computational methods use linear regression to estimate cell type-specific differential expression. Yet, they do not consider many artifacts hidden in high-dimensional gene expression …

Interactomics-Based Functional Analysis: Using Interaction Conservation To Probe Bacterial Protein Functions, J. Harry Caufield

Theses and Dissertations

The emergence of genomics as a discrete field of biology has changed humanity’s understanding of our relationship with bacteria. Sequencing the genome of each newly-discovered bacterial species can reveal novel gene sequences, though the genome may contain genes coding for hundreds or thousands of proteins of unknown function (PUFs). In some cases, these coding sequences appear to be conserved across nearly all bacteria. Exploring the functional roles of these cases ideally requires an integrative, cross-species approach involving not only gene sequences but knowledge of interactions among their products. Protein interactions, studied at genome scale, extend genomics into the field of …

System Genetic Analysis Of Mechanisms Underlying Excessive Alcohol Consumption, Maren L. Smith

Theses and Dissertations

Increased alcohol consumption over time is one of the characteristic symptoms of Alcohol Use Disorder (AUD). The molecular mechanisms underlying this escalation in intake is still the subject of study. However, the mesocortical and mesolimbic dopamine pathways, and the extended amygdala, because of their involvement in reward and reinforcement are believed to play key roles in these behavioral changes. Multiple gene expression studies have shown that alcohol affects the expression of thousands of genes in the brain. The studies discussed in this document use the systems biology technique of co-expression network analysis to attempt to find

patterns within genome-wide expression …

Genomic Comparisons And Genome Architecture Of Divergent Trypanosoma Species, Katie Bradwell

Theses and Dissertations

Virulent Trypanosoma cruzi, and the non-pathogenic Trypanosoma conorhini and Trypanosoma rangeli are protozoan parasites with divergent lifestyles. T. cruzi and T. rangeli are endemic to Latin America, whereas T. conorhini is tropicopolitan. Reduviid bug vectors spread these parasites to mammalian hosts, within which T. rangeli and T. conorhini replicate extracellularly, while T. cruzi has intracellular stages. Firstly, this work compares the genomes of these parasites to understand their differing phenotypes. Secondly, genome architecture of T. cruzi is examined to address the effect of a complex hybridization history, polycistronic transcription, and genome plasticity on this organism, and study its highly …

Evaluating And Improving The Efficiency Of Software And Algorithms For Sequence Data Analysis, Hugh L. Eaves

Theses and Dissertations

With the ever-growing size of sequence data sets, data processing and analysis are an increasingly large portion of the time and money spent on nucleic acid sequencing projects. Correspondingly, the performance of the software and algorithms used to perform that analysis has a direct effect on the time and expense involved. Although the analytical methods are widely varied, certain types of software and algorithms are applicable to a number of areas. Targeting improvements to these common elements has the potential for wide reaching rewards. This dissertation research consisted of several projects to characterize and improve upon the efficiency of several …

A Mechanistic Study Of An Ipsc Model For Leigh’S Disease Caused By Mtdna Mutataion (8993 T>G), John P. Galdun

Theses and Dissertations

Mitochondrial diseases encompass a broad range of devastating disorders that typically affect tissues with high-energy requirements. These disorders have been difficult to diagnose and research because of the complexity of mitochondrial genetics, and the large variability seen among patient populations. We have devised and carried out a mechanistic study to generate a cell based model for Leigh’s disease caused by mitochondrial DNA mutation 8993 T>G. Leigh’s disease is a multi-organ system disorder that depends heavily on the mutation burden seen within various tissues. Using new reprogramming and sequencing technologies, we were able to show that Leigh’s disease patient fibroblasts …

A Pipeline For Creation Of Genome-Scale Metabolic Reconstructions, Shaun W. Norris

Theses and Dissertations

The decreasing costs of next generation sequencing technologies and the increasing speeds at which they work have lead to an abundance of 'omic datasets. The need for tools and methods to analyze, annotate, and model these datasets to better understand biological systems is growing. Here we present a novel software pipeline to reconstruct the metabolic model of an organism in silico starting from its genome sequence and a novel compilation of biological databases to better serve the generation of metabolic models. We validate these methods using five Gardnerella vaginalis strains and compare the gene annotation results to NCBI and the …

Dysregulation Of Micrornas In Blood As Biomarkers For Diagnosing Prostate Cancer, Rhonda W. Daniel

Theses and Dissertations

Prostate cancer is the most common noncutaneous cancer among men, yet current diagnostic methods are insufficient and more reliable diagnostic markers need to be developed. The answer that can bridge this gap and enable more efficient diagnoses may lie in microRNAs. These small, single stranded RNA molecules impact protein expression at the translational level and regulate important cellular pathways. Dysregulation of these small RNA molecules can have tumorigenic effects on cells and lead to many types of cancers.

Currently the Prostate-Stimulating Antigen (PSA) is used as a diagnostic marker for prostate cancer. However, many factors can elevate PSA levels such …

Mysteries Of The Trypanosomatid Maxicircles: Characterization Of The Maxicircle Genomes And The Evolution Of Rna Editing In The Order Kinetoplastida, Preethi Ranganathan Iyengar

Theses and Dissertations

The trypanosomatid protists belonging to Order Kinetoplastida are some of the most successful parasites ever known to mankind. Their extreme physiological diversity and adaptability to different environmental conditions and host systems make them some of the most widespread parasites, causing deadly diseases in humans and other vertebrates.

This project focuses on their unique mitochondrion, called the kinetoplast, and more specifically involves the characterization of a part of their mitochondrial DNA (also called kinetoplast DNA or kDNA), the maxicircles, which are functional homologs of eukaryotic mitochondrial DNA in the kinetoplastid protists. We have sequenced and characterized the maxicircle genomes of 20 …