Molecular Biology Commons^™

Investigating The Role Of Tgf-Beta Signaling In Acoel Regeneration & Fission, Franchesca A. Aziz

Undergraduate Honors Theses

Whole-body regeneration and asexual reproduction are widespread in the Metazoa, yet little is known about the genetic systems that drive the regeneration process outside of a few model organisms. While many animals utilize fission followed by regeneration to accomplish asexual reproduction, Convolutriloba longifissura is unusual in performing a double fission, requiring significant anterior-posterior and medial-lateral regeneration that alters the orthogonal body axes in adult tissues. To better understand the process of axial re-specification during postembryonic development, we studied the genetic mechanisms used by C. longifissura to modify and respecify axial polarity during asexual reproduction and subsequent regeneration. Because conserved signaling …

Elucidating The Impact Of Sos-Response Timing In On Escherichia Coli Survival Following Treatment With Fluoroquinolone Topoisomerase Inhibitors, Stephanie Schofield

Honors Scholar Theses

Antibiotic treatment failure is a public health crisis, with a 2019 report stating that roughly 35,000 deaths occur in the United States yearly due to bacterial infections that are unresponsive to antibiotics (1). One complication in the treatment of bacterial infection is antibiotic persistence which further compromises our battle to effectively treat infection. Bacterial persisters can exist in clonal bacterial cultures and can tolerate antibiotic treatment by undergoing reversible phenotypic changes. They can survive drug concentrations that their genetically identical kin cannot. Some persisters remain in a slow growing state and are difficult to target with current antibiotics. A specific …

Long-Range Regulation By The Shigella Virulence Gene Regulator, Virb, Cody Cris

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nucleoid-structuring proteins (NSPs) in bacterial cells can exert gene regulatory effects over great distances on DNA. This contrasts with the traditional view of bacterial transcriptional regulation, where transcription factors bind cis-acting regulatory sites proximal (<250 bp) to promoters to influence gene expression. In Shigella species, the histone-like nucleoid-structuring protein (H-NS) transcriptionally silences many genes on the large (~220 kb) virulence plasmid. During host colonization, however, silencing by H-NS is alleviated by the anti-silencer protein, VirB, which remodels the H-NS:DNA complex. This transcriptional anti-silencing is mediated by VirB:DNA interactions and the modulation of DNA supercoiling, which lead to the up-regulation of virulence genes. VirB is a central regulator of Shigella virulence, but the mechanistic basis for transcriptional regulation is incompletely characterized. Here, I focus on the potential for VirB to regulate transcription from remotely located DNA binding sites. Employing complementary in vivo approaches, I assessed the spatial stringency of the VirB binding site and elucidated how varying cellular VirB levels impacts regulation over different distances. I also evaluated how a molecular roadblock on DNA influences remote regulation by VirB. Additionally, I developed control tools to validate the ability of VirB to spread along DNA, an activity of VirB that putatively drives transcriptional regulation. These data are consistent with transcriptional anti-silencing being driven by VirB spreading along DNA. Overall, these findings highlight how VirB is not a conventional transcriptional regulator and broaden our perspective on transcriptional control in bacteria. Furthermore, this work contributes to our understanding of long-range gene regulatory effects, which are frequently overlooked and poorly characterized in bacteria.

Neuronal Or Intestinal Knockdown Of C. Elegans Nadk-1 Decreases Oxygen Consumption And Reactive Oxygen Species, Jake Regan

Electronic Theses and Dissertations

Reactive oxygen species (ROS) such as H2O2 can damage cellular components and are formed as a byproduct of mitochondrial oxidative metabolism. Studies using the nematode C. elegans have found that increasing ROS during development or early adulthood can extend lifespan, while increasing ROS during later adulthood normally decreases lifespan. NADPH provides the reducing power for several cellular antioxidants and is synthesized in a two-step reaction from NAD+ with the first step being catalyzed by NAD kinase (NADK). In this study, the effects of knocking down C. elegans cytoplasmic NADK, nadk-1 globally or in a neuron or intestine-specific manner starting from …

Cyclic-Di-Gmp Regulates Salmonella Typhimurium Infection Of Epithelial Cells And Macrophages, Abdulafiz Musa

Electronic Theses and Dissertations

Regulation of the bacterial second messenger cyclic-di-GMP in Salmonella Typhimurium allows it to delicately alter phenotypes to optimize invasion and survive intracellularly in epithelial cells and macrophages to become virulent and cause infection. Cyclic-di-GMP concentration is regulated by the presence of external stimuli, sensory diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), and cyclic-di-GMP binding effectors. Previous studies established that maintenance of low cyclic-di-GMP concentrations is required for survival in macrophages, and that deletion of 3 active PDEs reduces this survival. Here I showed that these 3 PDEs also influenced the infection of epithelial cells. Further studies re-established the decreased survival in …

Gonads Without Glp-1: Silencing Glp-1 In The Male Somatic Gonad In Caenorhabditis Elegans, Matthew Titus

Undergraduate Theses

In C. elegans, the gene glp-1 encodes for a Notch receptor called GLP-1, one of two found in C. elegans’ genome. The gene has been previously implicated in the development of the hermaphroditic germline as well as playing a role in the mitosis/meiosis decision. Genetic screening has further identified it as potentially playing a role in the development of the male somatic gonad, making it an ideal candidate for a reverse genetic. We did this by silencing glp-1 and observing if any alterations to the gonad’s phenotype occur.

Normally this could be done by performing a gene knockout. …

Novel Plant Peroxidase Investigation For Use In Various Biochemical And Practical Applications, Sally Hess

Liberty University Research Week

Undergraduate

Basic

Characterization Of A Sas3 Homolog In The Human Pathogenic Yeast Cryptococcus Neoformans, Lillianne Bartone

Liberty University Research Week

Undergraduate

Basic

The Application Of Microbial Source Tracking To Aid In Site Prioritization For Remediation In Lower Michigan, John J. Hart

Masters Theses

Non-point source fecal pollution is a threat to both the environment and public health. Climate change, aging infrastructure, and intensified agricultural practices are predicted to accentuate this issue. In Michigan, due to the high instance of aging infrastructure and intensified agriculture, non-point source fecal pollution has caused many waterbodies to exceed the state standards posing a risk to recreational activities and source water. Due to this threat, there is an increased effort to identify and remediate these sources. My study focused on improving the identification of non-point source fecal pollution through a combination of culture-based and molecular fecal indicator bacteria …

Serving Justice Case By Case, Michael Becker

WRIT: Journal of First-Year Writing

Forensic Science is an integral part of serving justice in today's society, and majority of the world has little understanding of what forensics is. Read this article on forensic science and how it relates to writing in today's world.

In Vitro Characterization Of Fluorogenic Chemical Tools To Study Human Carboxylesterases (Cess), Taylor Parish Spidle

Undergraduate Honors Theses

Human carboxylesterases (CESs) are enzymes that are responsible for the metabolism of many important pharmaceuticals. Although CESs are key players in the hydrolysis of many ester-containing drugs, they remain understudied. Our group hypothesizes that this is primarily because there are few methods capable of reporting activity in live cells. Here, I report a new series of fluorogenic chemical tools to study the CES activity of one of the two major CESs in humans, CES1, in live cells. MCP-Me, MCP-Et, and MCP-iPr utilize the same carbonate group of a previously developed chemical tool in our group, FCP-1, and work to mimic …

Characterization And Genomic Analysis Of Two Escherichia Coli O157:H7 Bacteriophages Isolated From Pigeons, Mohamad I. Alolama

Dissertations

Enterohemorrhagic Escherichia coli, also known as EHEC, is a subset of Shiga toxin-producing E. coli (STEC), and it has recently been identified as one of the principal foodborne pathogens. E. coli O157:H7 is the most important serotype of STEC for its role in causing foodborne illnesses. E. coli O157:H7 could cause various gastroenteritis symptoms such as diarrhea, hemolytic uremic syndrome, hemorrhagic colitis, and thrombotic thrombocytopenic purpura and may cause death. Elimination of E. coli O157:H7 during food processing and storage is a possible solution. Bacteriophages have a significant impact on bacterial populations in nature due to their ability to …

Detection And Capture Of Nitrogen Fixing Bacteria From Soil And Roots Using Plant Specific Lectins, Alana Horton

Natural Sciences and Mathematics | Biological Sciences Master's Theses

Diazotrophs increase plant productivity by providing ammonia directly to plants in the rhizosphere or through association with the roots (Sun et al., 2021). Leveraging diazotrophs can aid in the reduction or application of harmful synthetic nitrogen fertilizers. This thesis aims to use plant root proteins, or lectins, to more rapidly recover viable diazotrophs that are likely to associate with crops. In this study, lectins, are used to recover bacteria from bulk soil by taking advantage of the binding relationship between lectins and bacterial cell surface polysaccharides. When commercially-available lectins were used with a magnetic pulldown to separate the lectin, bacterial …

Genetic Determinants Involved In Acquisition Of Iron In The Opportunistic Pathogen Mycobacterium Abscessus, Manal F. Farhat

Dissertations, Theses, and Capstone Projects

The opportunistic pathogen Mycobacterium abscessus subsp. abscessus (Mab) has become an emerging public health threat due to the increasing number of Mab-associated chronic pulmonary disease cases. Infection cure rates are only 50% due to the complex resistance of Mab to most antimicrobial drugs and chemotherapy.

Deeper knowledge of Mab biology is needed to illuminate potential candidates for development of improved therapeutics against Mab infections. The ESX-3 type VII protein secretion system of Mab plays an important role in host inflammatory and pathological responses during infection.

In this study, we demonstrate a functional link between the ESX-3 secretion …

Change And Stasis Of Distinct Sediment Microbiomes Across Port Everglades Inlet (Pei) And The Adjacent Coral Reefs, Lauren E. Krausfeldt, Jose V. Lopez, Catherine Bilodeau, Hyo Won Lee, Shelby L. Casali

Biology Faculty Articles

Deep water ports are human built coastal structures that by definition welcome ship traffic and disturbance. Evidence is accumulating that enhanced port activities such as dredging or deepening have negatively affected nearby natural habitats. Port Everglades Inlet (PEI) is a large active South Florida cargo port for over two million people and lies adjacent to coral reefs, dwindling mangroves, and recreational beaches. In this study, the microbial communities of PEI and adjacent reef sediments were characterized to serve as indicators for change due to dredging and assess anthropogenic influence on these sensitive ecosystems by sequencing the V4 region of 16S …

Molecular Regulation Of The Salicylic Acid Hormone Pathway In Plants Under Changing Environmental Conditions, Christina A. M. Rossi, Eric J. R. Marchetta, Jong Hum Kim, Christian Castroverde

Biology Faculty Publications

Salicylic acid (SA) is a central plant hormone mediating immunity, growth, and development. Recently, studies have highlighted the sensitivity of the SA pathway to changing climatic factors and the plant microbiome. Here we summarize organizing principles and themes in the regulation of SA biosynthesis, signaling, and metabolism by changing abiotic/biotic environments, focusing on molecular nodes governing SA pathway vulnerability or resilience. We especially highlight advances in the thermosensitive mechanisms underpinning SA-mediated immunity, including differential regulation of key transcription factors (e.g., CAMTAs, CBP60g, SARD1, bHLH059), selective protein–protein interactions of the SA receptor NPR1, and dynamic phase separation of the recently identified …

Interferon Gamma Signaling In Ovarian Cancer Cells, Bijaya Gaire

Theses and Dissertations

Interferon gamma (IFNγ) is a pleiotropic cytokine that can have, depending on the cellular and molecular context, both anti-tumor and pro-tumorigenic functions. IFNγ expression can be induced in cancer cells in response to radiation therapy or immune checkpoint blockade used in cancer treatment. We have previously shown that IFNγ induces expression of the Bcl3 proto-oncogene in ovarian cancer (OC) cells, resulting in their increased proliferation and migration, but the mechanisms are unknown. Here, I demonstrate that the IFNγ-induced Bcl3 expression is dependent on JAK1 and STAT1 signaling, and on p65 NFkB. Furthermore, my data show that the IFNγ-induced Bcl3 expression …

Role Of Integrins In Hiv Infection Of Resting Cd4+ T Cells Stimulated By Intestinal Endothelial Cells, Anding Shen, Sarah Logan, Tim Kim, Zihan Zhang

Summer Research

Eradicating HIV remains a formidable challenge due to the persistence of latent reservoirs within resting CD4+ T cells. Intestinal endothelial cells (IECs) have been shown to promote HIV infection and latent reservoir formation in resting CD4+ T cells. Our research investigates the role of integrins and their ligands, specifically ICAM, VCAM, and MAdCAM, in resting T cells and their impact on productive and latent HIV infection. Findings reveal that VCAM stimulation was the most effective in promoting productive HIV infection. MAdCAM and ICAM had minimal effect. Cytokine IL-6 consistently displayed synergy with all CAMs, amplifying effects on productive HIV infection. …

Regulation Of P53 By Trpm6 And Trpm7, Thomas Whitbread

Theses and Dissertations

TRPM6 and TRPM7 are two divalent metal cation channels that also possess a serine/threonine kinase domain. They both play critical roles in cellular and organismal metal homeostasis, and are necessary for proper embryonic development and human health. They may function independently in homomeric units, or act together as heterotetramers that display unique characteristics compared to the homomeric channels. These channel-kinases have increasingly been linked to cancer, displaying altered expression levels in a variety of human cancers and contributing to disease progression. Prior work has shown that TRPM6 and TRPM7 can participate in cancer-related signaling pathways. Here, the potential for TRPM6 …

Trichloroethylene (Tce) And Metabolite S-(1,2-Dichlorovinyl)-L-Cysteine (Dcvc) Alters Pregnancy Mediators In Rat Amniotic Fluid And Thp-1 Cells, Audrey Luce, Lyric Johnson, Karena Moleakunnel, Eleanor Scheeres, Emily Schellenboom, Sean Harris, Erica Boldenow

Summer Research

• Proinflammatory cytokines, such as TNF-α recruit immune cells to help fight infection and aid in cervical ripening (i.e. dilation).

• Matrix metalloproteinases (MMPs) such as MMP-9 help with rupture of the gestational membranes (i.e. breaking of the water).

• Prostaglandins, such as PGE2 contribute to myometrial contractions and labor induction.

• Working pregnant women are exposed to both toxicants and pathogens which can contribute to adverse birth outcomes such as preterm birth.

Analyzing Mex67 Interaction With The Ssa4 Transcript For Selective Export, Gretchen E. Stalnaker, Rebecca Adams

Science University Research Symposium (SURS)

In eukaryotic cells, such as the budding yeast Saccharomyces cerevisiae, mRNA export is the essential process in which mature mRNA is transported from its site of production, the nucleus, through the nuclear pore complex (NPC) to the cytoplasm, where it can then be translated into protein. This is accomplished when a transcript interacts with the mRNA export protein Mex67, which shuttles the message across the NPC. When the cell is under conditions of stress, such as heat shock, most mRNA export is prohibited, allowing for selective gene expression that prioritizes cell recovery. Specifically, SSA4, which encodes a protein that …

Testing Ssa4:Ade3 Reporters For Mcs Screening, Karah Edmonds, Rebecca Adams

Science University Research Symposium (SURS)

In eukaryotic cells, after transcription, mRNA is escorted from the nucleus to the cytoplasm to be translated. This process, called mRNA export, is essential for gene expression. However, when the cell exists in stressful conditions, mRNA export becomes regulated, and only select transcripts, including the stress-responsive SSA4 mRNA, can be exported. This project aims to uncover the mechanism of selective SSA4 mRNA export by generating a reporter that enables phenotypically visible expression under stressful conditions. Specifically, the ADE3 ORF was placed under the regulatory sequence of SSA4, which was anticipated to induce a red color for colonies only following stress. …

Dna Methylation And The Response To Infection In Introduced House Sparrows, Melanie Gibson

College of Graduate Studies: Theses & Dissertations

Epigenetics is the study of molecular modification of a genome without changing its base pairs. The most studied type of epigenetic mechanism is DNA methylation, which is capable of turning a gene “on” or “off.” Epigenetic potential is the capacity to which an individual can have methylation on its genome. The more CpGs available, the greater the epigenetic potential. In invasive species, genetic variation has been observed to be paradoxical: not much of it exists on a genomic level, but epigenetically, phenotypic variation can occur. The focus on shift in gene expression in this study is on Toll-Like Receptor 4 …

Characterization Of Parp1-Dependent Poly-Adp-Ribosylation Of Sprtn, Quincee Simonson

Electronic Theses and Dissertations

DNA-protein crosslinks (DPCs) are a type of DNA lesion that form when proteins become covalently linked to DNA. It is estimated that replicating cells experience approximately 6,000 DPCs per day per genome during exponential growth (Ruggiano & Ramadan, 2021). If left unrepaired, DPCs can be lethal to cells. For this reason, cells have evolved multiple pathways to repair or bypass DPCs to survive. One such pathway involves SPRTN, a nuclear metalloprotease that plays a key role in the repair of DPCs through direct proteolysis (Lopez-Mosqueda et al., 2016; Vaz et al., 2016). Once SPRTN degrades the bulky protein component of …

Producing Grnas For Use In Crispr-Cas9 Dna Editing Applications Via In Vivo T7 Rna Polymerase Transcription In Escherichia Coli., Christian A. Santiago

Honors Program Theses

The development of the CRISPR-Cas9 system is widely considered to be a breakthrough advancement in gene editing. Compared to traditional technologies, CRISPR is generally regarded as the most accessible, effective, and precise tool for inducing stable and inheritable gene edits in vivo. The CRISPR-Cas9 gene editing complex relies on the complementary binding of guide RNAs to specifically target a DNA sequence for endonuclease cleavage and mutagenesis. The production of gRNAs for use in CRISPR applications can become exceedingly complex and costly, as in vivo methodologies generally require the use of RNA polymerases that interfere with gRNA sequence identity and in …

Of Transcription Factor And Transformation: Elucidating Gene Function In The Common Ice Plant, Mesembryanthemum Crystallinum, Chinenye Lilian Izuegbunam

Dissertations and Theses

Abiotic stresses negatively affect plant growth and development across the globe, which also affect the production of food, feed, biofuel, and fiber to meet the demands of a growing population. Thus, developing novel strategies to increase abiotic stress tolerance in crops is necessary. One of these strategies is exploring transcription factors (TFs) in Crassulacean Acid Metabolism (CAM) plants to improve plant abiotic stress tolerances. Therefore, the first objective of this dissertation determine the abiotic stress tolerance function of a CAM TF, McHB7opt in Arabidopsis. This study found that McHB7opt increased stress-responsive pathways related to seed germination and early seedling development. …

Novel Mechanistic Insight Into Ciliary Regulation: Old Pathways Yield New Mechanisms, Larissa L. Dougherty

Dartmouth College Ph.D Dissertations

Cilia are structures present on most eukaryotic cells which provide important signaling and motile components to cells from early development to fully differentiated and matured cells. Regulation of these structures is critical to proper functioning of the cell and is known to be tied to the cell cycle. Preparation for ciliary assembly following cell cycle exit and ciliary disassembly following cell cycle reentry requires components throughout the cell body and within the cilium to facilitate this process. Here I identify how the cell adapts to ensure modifications to cilia occur for assembly or disassembly using the model organism Chlamydomonas reinhardtii. …

Tissue And Sex-Dependent Regulation Of Innate Immunity And Rna Editing In Mice, Kelsey R. Kendrick

Graduate Theses/Dissertations

Inflammation occurs as a result of insult or infection within the body. Individual cells respond to inflammation by upregulating genes that help mediate the immune response, such as ADAR1. ADAR1 helps regulate the immune response but also catalyzes a process called RNA editing. RNA editing alters the sequence of select mRNAs to alter the encoded proteins. The result is altered function of the encoded protein, which is often beneficial for the cell. Our goal was to determine how inflammation affects the function of ADAR1. Since we know that the effects of inflammation vary between different organs and sexes, we examined …

Molecular Investigation Of Minor Genomic Populations And Biological Exposures In Human Health, Brandon Ned Johnson

Dissertations and Theses

The study of genetics has contributed to countless discoveries related to human health and disease. However, the complexities of human biology reside not only in the genome but also in the contributions from environmental exposures, as measured via the classical twin design. To understand the influence of biological exposures, I implemented study designs to explore both the health associations and propagation of foreign genetic material. Microchimerism has been studied for association with several clinical conditions, and I further investigated if male microchimerism could elucidate the etiology of Mayer-Rokitansky-Küster-Hauser syndrome. Prevalence of male microchimerism in women with no history of pregnancy …

Use Of Foreign Edna Tracers To Resolve Site- And Time-Specific Edna Distributions In Natural Streams, Braden A. Herman

Cal Poly Humboldt theses and projects

Substantial uncertainty in how to interpret eDNA observations motivates a need for a technique to effectively and efficiently measure of system- and time-specific eDNA distributions. Using a technique to robustly calibrate eDNA dynamics in a given system would improve established eDNA methods such as presence and absence and has the potential to refine estimates of organism abundance using eDNA concentration that are less well understood. Particles of eDNA are present in a wide variety of size and type resulting in varying transport dynamics, persistence, decay, among others. This variation likely makes eDNA transport more complex than that of conservative tracers …