Genetics and Genomics Commons^™

The Evolution Of Genomic Imprinting: Theories, Predictions And Empirical Tests, M M. Patten, L Ross, J P. Curley, David C. Queller, R Bonduriansky, J B. Wolf

Biology Faculty Research

The epigenetic phenomenon of genomic imprinting has motivated the development of numerous theories for its evolutionary origins and genomic distribution. In this review, we examine the three theories that have best withstood theoretical and empirical scrutiny. These are: Haig and colleagues’ kinship theory; Day and Bonduriansky’s sexual antagonism theory; and Wolf and Hager’s maternal–offspring coadaptation theory. These theories have fundamentally different perspectives on the adaptive significance of imprinting. The kinship theory views imprinting as a mechanism to change gene dosage, with imprinting evolving because of the differential effect that gene dosage has on the fitness of matrilineal and patrilineal relatives. …

Potential Roles Of Peroxidases In Caenorhabditis Elegans Innate Immunity, George R. Tiller, George R. Tiller

Dissertations and Theses (Open Access)

The production of ROS (reactive oxygen species) in response to pathogen detection is a rapid, nonspecific response that is evolutionarily conserved from nematodes to humans. ROS serve as direct and indirect effectors of innate and adaptive immunity. In Caenorhabditis elegans, a ROS burst is observed during infection and is mediated by the dual oxidase BLI-3, which produces H₂O₂. RNAi (RNA interference) to reduce the amount of BLI-3 results in a significant increase in susceptibility to pathogens, suggesting BLI-3 has a role in the immune response. However, H₂O₂ by itself is not a …

Development Of Chimeric Type Iv Secretion Systems For Transfer Of Heterologous Substrates Across The Gram-Negative Cell Envelope, Trista M. Berry

Dissertations and Theses (Open Access)

Many bacteria use Type IV Secretion Systems (T4SSs) to aid in pathogenesis by translocating virulence factors across the cell envelope and into eukaryotic cells. These systems are structurally and functionally diverse, but are often compared to the archetypal VirB/VirD4 T4SS of Agrobacterium tumefaciens. This system is composed of the VirD4 type IV coupling protein (T4CP) and 11 VirB subunits (VirB1-11) that assemble as the secretion channel and an extracellular pilus. The T4CP is an inner membrane ATPase that interacts with T4SS substrates and the secretion channel, and is thought to link substrates with the secretion channel and possibly energize …

Development Of A Molecular Gram-Stain Assay For The Diagnosis Of Blood Stream Infections Associated With Sepsis, Douglas Bryan Litwin

Dissertations and Theses (Open Access)

Sepsis is a serious medical condition resulting from the severe dysregulation of the immune response that is generally triggered by infection. It affects more than 1.1 million Americans, has an average mortality rate of 30%, and is estimated to cost $24.3 billion annually. Currently, blood culture followed by Gram-stain analysis is the gold standard for diagnosing bacterial infections associated with sepsis. This method generates a high rate of false negative results and, in general, requires 20 to 48 hr to provide results. Both of these problems are related to the requirement that the bacterial pathogens grow under defined laboratory conditions. …

Regulation Of Strand-Specific Processing In Human Pre-Mir-371 And Its Mouse Homologs, Jianting Shi

Graduate School of Biomedical Sciences Theses and Dissertations

MicroRNAs (miRNAs) are small noncoding RNAs, known to regulate genes by inducing target mRNA degradation or translational repression. This regulatory function has been shown to assist developmental timing control and increasingly more evidence reveals some of the miRNAs may have tissue/cell type-specific function, showing the potential to assist cell differentiation. Mouse miR-290-295 cluster is embryonic stem cell (ESCs)-specific miRNA cluster and human miR-371-373 cluster has been verified to be its functional homolog. We have previously demonstrated that human pre-miR-371 is processed into multiple miRNA species, which represent the seeds of the mouse of miR-290-5p, miR-292-5p, miR-292-3p-iso2 and miR-293-3p. Deep sequencing …

Functional Genomics Of Maize Endosperm Maturation And Protein Quality, Lingling Yuan

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Maize is one of the most important cereal crops and widely cultivated throughout the world. The study on maize kernel development including protein quality improvement is essential for removing dietary protein deficiency because of the lack of essential amino acids, especially lysine and tryptophan, in maize kernel. Quality Protein Maize (QPM) is a hard kernel variant of the high-lysine mutant, opaque-2. We created opaque QPM variants to identify opaque-2 modifier genes and to investigate deletion mutagenesis combined with Illumina sequencing as a maize functional genomics tool. A K0326Y-QPM deletion mutant, line 107, was null for the 27- and 50-kD …

Vcam-1/Α4Β1 Integrin Interaction Is Crucial For Prompt Recruitment Of Immune T Cells Into The Brain During The Early Stage Of Reactivation Of Chronic Infection With Toxoplasma Gondii To Prevent Toxoplasmic Encephalitis, Qila Sa, Eri Ochiai, Tomoko Sengoku, Melinda E. Wilson, Morgan Brogli, Stephen Crutcher, Sara A. Michie, Baohui Xu, Laura Payne, Xisheng Wang, Yasuhiro Suzuki

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Reactivation of chronic infection with Toxoplasma gondii can cause life-threatening toxoplasmic encephalitis in immunocompromised individuals. We examined the role of VCAM-1/α4β1 integrin interaction in T cell recruitment to prevent reactivation of the infection in the brain. SCID mice were infected and treated with sulfadiazine to establish a chronic infection. VCAM-1 and ICAM-1 were the endothelial adhesion molecules detected on cerebral vessels of the infected SCID and wild-type animals. Immune T cells from infected wild-type mice were treated with anti-α4 integrin or control antibodies and transferred into infected SCID or nude mice, and the animals received the same antibody every other …

Secretory Iga Is Concentrated In The Outer Layer Of Colonic Mucus Along With Gut Bacteria, Eric W. Rogier, Aubrey L. Frantz, Maria E. C. Bruno, Charlotte S. Kaetzel

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Antibodies of the secretory IgA (SIgA) class comprise the first line of antigen-specific immune defense, preventing access of commensal and pathogenic microorganisms and their secreted products into the body proper. In addition to preventing infection, SIgA shapes the composition of the gut microbiome. SIgA is transported across intestinal epithelial cells into gut secretions by the polymeric immunoglobulin receptor (pIgR). The epithelial surface is protected by a thick network of mucus, which is composed of a dense, sterile inner layer and a loose outer layer that is colonized by commensal bacteria. Immunofluorescence microscopy of mouse and human colon tissues demonstrated that …

Cd21 And Cd24 Co-Expression: A Translational Model Between Mouse And Human, Abigail Benitez

Loma Linda University Electronic Theses, Dissertations & Projects

Systemic Lupus Erythematosus and Rheumatoid Arthritis are B cell-mediated autoimmune diseases that afflict millions of people worldwide. B cell-targeted therapies for these diseases result in variable clinical outcomes. Thus, a need exists to better understand the dynamics of human B cell production and function. The mouse model has provided a foundation for understanding the mechanisms involved in human B cell development and autoimmune disease. However, differences in mouse and human B cells are not fully understood. Our work shows that the co-expression of CD21 and CD24, determined by 7-color flow cytometry, can be used to demarcate developmental subsets of B …

The Evolution Of Respiratory O2/No Reductases: An Out-Of-The-Phylogenetic-Box Perspective, Anne-Lise Ducluzeau, Barbara Schoepp-Cothenet, Robert Van Lis, Frauke Baymann, Michael J. Russell, Wilfgang Nitschke

Department of Biochemistry: Faculty Publications

Complex life on our planet crucially depends on strong redox disequilibria afforded by the almost ubiquitous presence of highly oxidizing molecular oxygen. However, the history of O₂-levels in the atmosphere is complex and prior to the Great Oxidation Event some 2.3 billion years ago, the amount of O₂ in the biosphere is considered to have been extremely low as compared with present-day values. Therefore the evolutionary histories of life and of O₂-levels are likely intricately intertwined. The obvious biological proxy for inferring the impact of changing O₂-levels on life is the evolutionary history …

An Examination Of The Phylogenetic Diversity Of Green Algae (Chlorophyceae) That Symbiose With Spotted Salamanders (Ambystoma Maculatum) In The Egg Stage., Crystal Xue

Honors Scholar Theses

In 1909, the species Oophila amblystomatis Lambert ex Wille was described for green algae that symbiose with salamanders in the egg stage (Wille). There are two hypotheses about the source of algae: 1) that algae enter from the surrounding water once the egg clutch is laid in a pond, and 2) that they are acquired from the maternal reproductive tract. We developed a third hypothesis developed to account for the salamander reproductive cycle. Male salamanders lay spermatophores, which are protein-filled capsules, on plant matter in and around ponds. Spermatophores are exposed to the environment before use by females in internal …

The Development Of A Comprehensive Antifungal Susceptibility Testing Assay For Vulvovaginal Candidiasis Therapy, David Hardaker

Graduate School of Biomedical Sciences Theses and Dissertations

Vulvovaginal candidiasis is the most common fungal infection of the female urogenital tract, commonly caused by Candida albicans and C. glabrata. However, treatment can be difficult when caused by non-albicans strains due to resistance to the oral antifungal drug fluconazole. The mechanism through which strains of Candida, particularly C. glabrata, develop resistance to different antifungal classes has not been completely characterized. The ergosterol biosynthesis pathway, an important component of the cell membrane, is the major target of antifungals such as fluconazole, an inhibitor of the ERG 11 gene. Current research shows that an upregulation of specific genes in C. glabrata …

Modulated Functions Of The Fanconi Anemia Core Complex, Yaling Huang

Dissertations and Theses (Open Access)

Cells derived from Fanconi anemia (FA) patients are characterized by hypersensitivity to DNA interstrand crosslinks (ICLs), suggesting that FA genes play a role in ICL repair. Fanconi anemia core complex (including A, B, C, E, F, G, L, FAAP20, and FAAP100) activates the Fanconi pathway by providing the essential E3 ligase activity for FANCD2 mono-ubiquitination. Previous studies suggested the existence of three protein-protein interaction groups. However, the functions of most FA core complex protein are still limited to their presence in the complex. How the spatially-defined FANCD2 ubiquitination is accomplished by the core complex remains unknown.

To elucidate the roles …

Natural And Exogenous Genome Editing In Wiskott-Aldrich Syndrome Patient Cells, Tamara J. Laskowski

Dissertations and Theses (Open Access)

Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency disease characterized by thrombocytopenia, recurrent infections and increased autoimmunity. This disease is caused by mutations in the WAS gene (WAS) which encodes for the WAS protein (WASp), exclusively expressed in hematopoietic cells and required for proper platelet production and lymphoid cell function. Approximately 11% of patients with WAS exhibit a phenomenon called Somatic Revertant Mosaicism which is characterized by the presence of lymphocytes which naturally revert back to normal phenotype by restoring WASp expression. To date, the mechanisms of this naturally-occurring gene therapy remains poorly understood, and the full extent …

Characterization Of Ftsa-Ftsn Interaction During Escherichia Coli Cell Division, [email protected] K. Busiek

Dissertations and Theses (Open Access)

Division of a bacterial cell into two equal daughter cells requires precise assembly and constriction of the division machinery, or divisome. The Escherichia coli divisome includes nearly a dozen essential cell division proteins that assemble at midcell between segregating sister chromosomes. FtsZ, a homolog of eukaryotic tubulin, is the first essential cell division protein to localize at midcell where it polymerizes into a ring-shaped scaffold (Z ring). Establishment of the Z ring is required for recruitment of downstream cell division proteins including FtsA, a cytoplasmic protein that tethers the Z ring to the inner membrane. Following localization of FtsA and …

The Mechanism Of Small Rna Biogenesis, Degradation, And Function In Arabidopsis, Meng Xie

School of Biological Sciences: Dissertations, Theses, and Student Research

Eukaryotic small RNAs play important roles in many biological processes through sequence-specific RNA silencing. In plants, there are mainly two small RNAs triggering gene silencing: microRNAs (miRNAs) and small interfering RNAs (siRNAs). The biogenesis and precise regulation of small RNA abundance are crucial for plant growth, development, genomic stability, and the resistance to both abiotic and biotic stresses. In this study, we used Arabidopsis thaliana, the model plant, to study the mechanism of RNA-directed DNA methylation (RdDM), in which siRNAs can trigger DNA methylation and gene silencing. In addition, we investigated the mechanism of miRNA biogenesis and degradation. For …

Combined Metagenomic And Phenomic Approaches Identify A Novel Salt Tolerance Gene From The Human Gut Microbiome, Eamon Culligan, Julian R. Marchesi, Colin Hill, Roy D. Sleator

Department of Biological Sciences Publications

In the current study, a number of salt-tolerant clones previously isolated from a human gut metagenomic library were screened using Phenotype MicroArray (PM) technology to assess their functional capacity. PM's can be used to study gene function, pathogenicity, metabolic capacity and identify drug targets using a series of specialized microtitre plate assays, where each well of the microtitre plate contains a different set of conditions and tests a different phenotype. Cellular respiration is monitored colorimetrically by the reduction of a tetrazolium dye. One clone, SMG 9, was found to be positive for utilization/transport of L-carnitine (a well-characterized osmoprotectant) in the …

A Morphological And Genetic Analysis Of Forensically Important Blow Flies, From Georgia: The Genus Lucilia, Katie S. Googe

Honors College Theses

Identification of Blow flies (Diptera: Calliphoridae) to species is important for estimating postmortem intervals, because insect species develop at different rates. Three Blow fly species in Georgia; Lucilia coeruleiviridis, L. cuprina, and L. sericata are similar morphologically, making identification difficult. Furthermore, the status of L. cuprina is in doubt; this species may be a complex of true L. cuprina, and L. cuprina x L. sericata hybrids. The objective of this study was to survey the Georgia Blow fly community and validate the statuses of L. coeruleiviridis, L. cuprina, and L. sericata, through morphological and …

Structural And Functional Analysis Of Harv1 Lipid Binding, Jamie Francisco

Graduate School of Biomedical Sciences Theses and Dissertations

Cardiovascular disease (CVD) has the highest mortality rate worldwide and is considered epidemic in the United States. Statins as the primary and almost sole method of treatment for cholesterol-related CVD, but they have limitations. Proper sterol transport is needed to maintain normal blood lipid levels. Studies have shown that misregulation of lipid trafficking aids in the progression of CVD and in the activation of the unfolded protein response (UPR). Misregulation of lipid and sterol homeostasis also results in the loss of lipid rafts, known cellular signaling hubs and major components of ER associated membrane contact sites. Arv1 is a highly …

An Lnvestigation Using Saccharornyces Cereylslae During Growth With Haloperidol On Different Carbon Sources, Elizabeth Garza

Honors Program Theses and Research Projects

Haloperidol is a first generation antipsychotic that is used to treat symptoms of psychosis in patients affected by schizophrenia. This class of antipsychotics is associated with neurological side effects. On the other hand, atypical antipsychotics, such as Clozapine, are associated with metabolic side effects. Ln order to better understand the metabolic basis for the different side effects, we compared the two classes of antipsychotics. Yeast was grown in the presence of Haloperidol on both fermentable and non fermentable carbon sources at concentrations of 0 uM, 1 uM, 5 uM, and 10 uM. The resultant cell viability and the reactive oxygen …

Cluster M Mycobacteriophages Bongo, Pegleg, And Rey With Unusually Large Repertoires Of Trna Isotopes, Welkin H. Pope, Kirk R. Anders, Madison Baird, Charles A. Bowman, Michelle M. Boyle, Gregory W. Broussard, Tiffany Chow, Kari L. Clase, Shannon Cooper, Kathleen A. Cornely, Randall J. Dejong, Veronique A. Delesalle, Lisa Deng, David Dunbar, Nicholas P. Edgington, Christina M. Ferreira, Kathleen Weston Hafer, Grant A. Hartzog, J. Robert Hatherill, Lee E. Hughes, Khristina Ipapo, Gregory P. Krukonis, Christopher G. Meier, Denise L. Monti, Matthew R. Olm, Shallee T. Page, Craig L. Peebles, Claire A. Rinehart, Michael R. Rubin, Daniel A. Russell, Erin R. Sanders, Morgan Schoer, Christopher D. Shaffer, James Wherley, Edwin Vazquez, Han Yuan, Daiyuan Zhang, Steven G. Cresawn, Deborah Jacobs-Sera, Roger W. Hendrix, Graham F. Hatfull

Biology Faculty Publications

Genomic analysis of a large set of phages infecting the common hostMycobacterium smegmatis mc²155 shows that they span considerable genetic diversity. There are more than 20 distinct types that lack nucleotide similarity with each other, and there is considerable diversity within most of the groups. Three newly isolated temperate mycobacteriophages, Bongo, PegLeg, and Rey, constitute a new group (cluster M), with the closely related phages Bongo and PegLeg forming subcluster M1 and the more distantly related Rey forming subcluster M2. The cluster M mycobacteriophages have siphoviral morphologies with unusually long tails, are homoimmune, and have larger than average …

Chip-Seq And Rna-Seq Reveal An Amrz-Mediated Mechanism For Cyclic Di-Gmp Synthesis And Biofilm Development By Pseudomonas Aeruginosa, Christopher J. Jones, David Newsom, Benjamin Kelly, Yasuhiko Irie, Laura K. Jennings, Binjie Xu, Dominique H. Limoli, Joe J. Harrison, Matthew R. Parsek, Peter White, Daniel J. Wozniak

Biology Faculty Publications

The transcription factor AmrZ regulates genes important for P. aeruginosa virulence, including type IV pili, extracellular polysaccharides, and the flagellum; however, the global effect of AmrZ on gene expression remains unknown, and therefore, AmrZ may directly regulate many additional genes that are crucial for infection. Compared to the wild type strain, a ΔamrZ mutant exhibits a rugose colony phenotype, which is commonly observed in variants that accumulate the intracellular second messenger cyclic diguanylate (c-di-GMP). Cyclic di-GMP is produced by diguanylate cyclases (DGC) and degraded by phosphodiesterases (PDE). We hypothesized that AmrZ limits the intracellular accumulation of c-di-GMP through transcriptional repression …

B Cell Tolerance In Health And Disease, Murali Gururajan, Vishal J. Sindhava, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

B lymphocyte receptors are generated randomly during the bone marrow developmental phase of B cells. Hence, the B cell repertoire consists of both self and foreign antigen specificities necessitating specific tolerance mechanisms to eliminate self-reactive B cells. This review summarizes the major mechanisms of B cell tolerance, which include clonal deletion, anergy and receptor editing. In the bone marrow presentation of antigen in membrane bound form is more effective than soluble form and the role of dendritic cells in this process is discussed. Toll like receptor derived signals affect activation of B cells by certain ligands such as nucleic acids …

Direct-To-Consumer Genetic Testing In The College Classroom: Knowledge, Attitudes, And Concerns Of Introductory Biology Students, Nicanor Austriaco

Biology Faculty Publications

Pioneered by companies like 23andMe.com, deCODEme.com, and Navigenics.com, direct-to-consumer genetic testing refers to genetic tests that are marketed directly to consumers via television, print media, or the Internet. This kind of testing provides access to a customer’s genetic information without necessarily involving either a medical health care professional or a genetic counselor in the process. In recent years, a course offered to medical and graduate students at Stanford University has included an option for students to undergo personal genotyping, raising the possibility that direct-to-consumer genetic testing could also be incorporated into undergraduate biology courses to enhance student learning. In this …

Epicatechin Stimulates Mitochondrial Activity And Selectively Sensitizes Cancer Cells To Radiation, Hosam A. Elbaz, Icksoo Lee, Deborah A. Antwih, Jenney Liu, Maik Hüttemann, Steven P. Zielske

Center for Molecular Medicine and Genetics

Radiotherapy is the treatment of choice for solid tumors including pancreatic cancer, but the effectiveness of treatment is limited by radiation resistance. Resistance to chemotherapy or radiotherapy is associated with reduced mitochondrial respiration and drugs that stimulate mitochondrial respiration may decrease radiation resistance. The objectives of this study were to evaluate the potential of (-)-epicatechin to stimulate mitochondrial respiration in cancer cells and to selectively sensitize cancer cells to radiation. We investigated the natural compound (-)-epicatechin for effects on mitochondrial respiration and radiation resistance of pancreatic and glioblastoma cancer cells using a Clark type oxygen electrode, clonogenic survival assays, and …

Deletion Of Aif1 But Not Of Yca1/Mca1 Protects Saccharomyces Cerevisiae And Candida Albicans Cells From Caspofungin-Induced Programmed Cell Death, Nicanor Austriaco, Christopher Chin, Faith Donaghey, Kathrine Helming, Morgan Mccarthy, Stephen Rogers

Biology Faculty Publications

Caspofungin was the first member of a new class of antifungals called echinocandins to be approved by a drug regulatory authority. Like the other echinocandins, caspofungin blocks the synthesis of β(1,3)-D-glucan of the fungal cell wall by inhibiting the enzyme, β(1,3)-D-glucan synthase. Loss of β(1,3)-D-glucan leads to osmotic instability and cell death. However, the precise mechanism of cell death associated with the cytotoxicity of caspofungin was unclear. We now provide evidence that Saccharomyces cerevisiae cells cultured in media containing caspofungin manifest the classical hallmarks of programmed cell death (PCD) in yeast, including the generation of reactive oxygen species (ROS), the …

The Role Of Angiotensinogen In Atherosclerosis And Obesity, Congqing Wu

Theses and Dissertations--Nutritional Sciences

Angiotensinogen is the only known precursor in the renin-angiotensin system, a hormonal system best known as an essential regulator of blood pressure and fluid homeostasis. Angiotensinogen is sequentially cleaved by renin and angiotensin- converting enzyme to generate angiotensin II. As the major effector peptide, angiotensin II mainly function through angiotensin type 1 receptor.

Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and more recently renin inhibitors are widely known as the 3 classic renin-angiotensin system inhibitory drugs against hypertension and atherosclerosis. Here, we developed an array of regents to explore the effects of angiotensinogen inhibition. First, we demonstrated that genetic deficiency of …

Structural And Functional Characterization Of The Mbd2-Nurd Co-Repressor Complex, Megha Desai

Theses and Dissertations

The MBD2-NuRD co-repressor complex is an epigenetic regulator of the developmental silencing of embryonic and fetal β-type globin genes in adult erythroid cells as well as aberrant methylation-dependent silencing of tumor suppressor genes in neoplastic diseases. Biochemical characterization of the MBD2-NuRD complex in chicken erythroid cells identified RbAp46/48, HDAC1/2, MTA1/2/3, p66α/β, Mi2α/β and MBD2 to comprise this multi-protein complex.

In the work presented in Chapter 2, we have pursued biophysical and molecular studies to describe a previously uncharacterized domain of human MBD2 (MBD2_IDR). Biophysical analyses show that MBD2_IDR is an intrinsically disordered region (IDR). Despite this inherent …

The Distribution Of Fitness Effects Of Spontaneous Mutations In Vibrio Fischeri, Chelsea K. Jones

Honors Theses and Capstones

Mutations are the ultimate source of the biological diversity on which natural selection acts, but the vast majority of these mutations are harmful. As such, mutations lead to disease states like cancer, extinction of small populations, and can drive pathogen evolution. Unfortunately, because mutations are rare and past studies have been subject to detection biases, very little is known about the distribution of fitness effects from naturally occurring mutations. In this study, we used mutation accumulation and full genome sequencing to capture naturally occurring mutations before they were exposed to the sieve of natural selection in Vibrio fischeri. We …

The Prevalence And Effect Of Wolbachia Infection On The Brown Widow Spider (Latrodectus Geometricus), Brittany Dane' Arrington

College of Graduate Studies: Theses & Dissertations

Wolbachia was recently identified in the Brown Widow Spider (Latrodectus geometricus). This symbiont has not previously been found in this genus, therefore the consequences on the host’s population dynamics are unknown. The frequency of endosymbiont infection can provide insight into the population dynamics of the host as this bacteria is known to alter host life history. In my 1^st chapter I determine the prevalence of Wolbachia pipentis infection in in the Brown Widow Spider (Latrodectus geometricus) from five locations in the Southeastern United States. Infection frequency differed significantly among sampling locations, ranging from 20% to …