Cell and Developmental Biology Commons^™

The Intracellular Behaviour Of Burkholderia Cenocepacia In Murine Macrophages, Jennifer S. Tolman

Electronic Thesis and Dissertation Repository

Burkholderia cenocepacia is an opportunistic pathogen causing life-threatening infections in cystic fibrosis and other immunocompromised patients. The bacterium survives within macrophages by interfering with typical endocytic trafficking, resulting in delayed maturation of a B. cenocepacia-containing phagosome. We hypothesize that B. cenocepacia alters gene expression after internalization by macrophages, inducing genes involved in intracellular survival and host adaptation. Furthermore, we hypothesize that specialized bacterial secretion systems are involved in the interactions between intracellular bacteria and macrophages. In this work, we characterize later-stage infection of macrophages by B. cenocepacia, showing replication within an acidified endosomal compartment suggestive of a phagolysosome. …

Brassinosteroid-Mediated Stress Tolerance In Arabidopsis Thaliana, Tawhidur Rahman

Electronic Thesis and Dissertation Repository

Brassinosteroids (BRs) are a group of steroidal plant hormones that are essential for proper plant development and also promote stress tolerance. Without BRs, plants are dwarfs and infertile. To understand the molecular mechanisms underlying BR-mediated stress tolerance, global gene expression analysis of untreated and 24-epibrassinolide (EBR)-treated Arabidopsis thaliana seedlings under non-stress and heat stress (HS) conditions was carried out. Microarray data analysis indicated that stress-related genes were predominant within the EBR up-regulated gene data set. Furthermore, several of these genes were abscisic acid (ABA) and jasmonic acid (JA) related. Measurements of endogenous hormones showed significant increases in the levels ABA …

The Evolution And Mechanics Of Translational Control In Plants, Justin N. Vaughn

Doctoral Dissertations

The expression of numerous plant mRNAs is attenuated by RNA sequence elements located in the 5' and 3' untranslated regions (UTRs). For example, in plants and many higher eukaryotes, roughly 35% of genes encode mRNAs that contain one or more upstream open reading frames (uORFs) in the 5' UTR. For this dissertation I have analyzed the pattern of conservation of such mRNA sequence elements. In the first set of studies, I have taken a comparative transcriptomics approach to address which RNA sequence elements are conserved between various families of angiosperm plants. Such conservation indicates an element's fundamental importance to plant …

Nuclear Receptors In Ecdysone-Mediated Programmed Cell Death In Drosophila Melanogaster, Ritika Sehgal

Masters Theses

The steroid hormone ecdysone plays vital roles during Drosophila development. Pulses of 20E during Drosophila life cycle function as temporal cues, signaling the onset of metamorphic processes, including the stage specific programmed cell death of larval tissues. Ecdysone is the critical developmental cue orchestrating the metamorphic reformation of CNS, resulting in the formation of adult-specific neural circuitry. Ecdysone signaling is transduced by a heterodimeric receptor complex formed between two nuclear receptors: EcR and Ultraspiracle (USP). There are 18 nuclear receptors known in Drosophila and EcR is the only receptor whose functions in neuronal PCD have been well recognized. Therefore, the …

Gene Discovery In Nonsyndromic Cleft Lip With Or Without Cleft Palate, Brett T. Chiquet

Dissertations & Theses (Open Access)

Nonsyndromic cleft lip with or without cleft palate (NSCLP), a common, complex orofacial birth defect that affects approximately 4,000 newborns each year in the United States, is caused by both genetic and environmental factors. Orofacial clefts affect the mouth and nose, causing severe deformity of the face, which require medical, dental and speech therapies. Despite having substantial genetic liability, less than 25% of the genetic contribute to NSCLP has been identified. The studies described in this thesis were performed to identify genes that contribute to NSCLP and to demonstrate the role of these genes in normal craniofacial development. Using genome …

Cell Polarity Regulates Organ Growth Through The Hippo Pathway, Chiao-Lin Chen

Dissertations & Theses (Open Access)

Defects in apical-basal cell polarity and abnormal expression of cell polarity determinants are linked to human cancer. Loss of polarity is highly correlated with malignancy. In Drosophila, perturbation of apical-basal polarity, including overexpressing the apical determinant Crumbs, can lead to uncontrolled tissue growth. Cells mutant for the basolateral determinant scribble overproliferate and can form neoplastic tumors. Interestingly, scribble mutant clones that arise in wild-type tissues are eliminated and therefore do not manifest their tumorigenic potential. However, the mechanisms by which cell polarity coordinates with growth control pathways in developing organs to achieve appropriate organ size remain obscure.

To investigate …

Axogial Communication Mediated By Soluble Neuregulin-1 And Bdnf, Zhenzhong Ma

Wayne State University Dissertations

During peripheral nervous system development, successful communication between axons and glial cells including Schwann cells in peripheral nervous system and oligodendrocytes in central nervous system, is required for the proper functions of both neurons and glia. Three types of alternatively-spliced proteins belonging to the neuregulin1 (NRG1) gene family of growth and differentiation factors are essential for Schwann cell survival and peripheral nerve development. While membrane-bound NRG1 forms (type III) has been strongly implicated in the regulation of myelination process at late stage of Schwann cell development, little is known about the role of soluble, heparin-binding forms of NRG1 (type I/II) …

Loss Of Bloom Syndrome Protein Causes Destabilization Of Genomic Architecture And Is Complemented By Ectopic Expression Of Escherichia Coli Recg In Human Cells, Michael Wayne Killen

University of Kentucky Doctoral Dissertations

Genomic instability driven by non-allelic homologous recombination (NAHR) provides a realistic mechanism that could account for the numerous chromosomal abnormalities that are hallmarks of cancer. We recently demonstrated that this type of instability could be assayed by analyzing the copy number variation of the human ribosomal RNA gene clusters (rDNA). Further, we found that gene cluster instability (GCI) was present in greater than 50% of the human cancer samples that were tested. Here, data is presented that confirms this phenomenon in the human GAGE gene cluster of those cancer patients. This adds credence to the hypothesis that NAHR could be …

A Breast Cancer Stem Cell Model Created From Mmtv-Pymt Mice Applicable To Human Breast Cancer, Denise Grant Lanza

Legacy Theses & Dissertations (2009 - 2024)

Cancer stem cells are the seeds of tumor growth, but there are limited cell-based methods that exist to study the properties of these cells. To create a model of breast cancer stem cells, we isolated tumors from MMTV-PyMT mice. Two out of the four different cell types isolated survived in culture, CD44+CD24- and CD24+CD49f+CD44low. We found that we could initiate tumors with as few as 10 cells injected subcutaneously in the hind leg or orthotopically in the cleared fat pad with CD24+ cells. However, we could not initiate tumors with injection of CD24- cells. We found a requirement for TICs …

The Role Of Trm9 In Stress Responses, Ashish Ravindra Patil

Legacy Theses & Dissertations (2009 - 2024)

Cells need to respond appropriately to environmental changes in order to maintain homeostasis. The cellular response to an environmental stress is regulated at transcriptional, translational and post translational levels. The tRNA, which acts as an adaptor molecule between the mRNA and the protein, plays an important role in the translational regulation of cellular responses to stress and is one of the most heavily modified biomolecules. In Saccharomyces cerevisiae , the wobble uracil of the tRNA(3'-UCU-5') Arg, tRNA(3'-UUC-5') Glu and certain other specific tRNAs are modified to 5-methoxycarbonylmethyluridine (mcm5U) and 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) residues by the tRNA methyltransferase 9 (Trm9). Modifications at …

From Dna To Protein: A Study Of Genomic Instability Candidate Genes During Zebrafish Development, Kristine Griffett

USF Tampa Graduate Theses and Dissertations

The zebrafish, Danio rerio, is a type of freshwater minnow often used to model human diseases including cancer, anxiety and aging diseases. The overall biology of zebrafish is strikingly similar to that of humans, allowing these fish to be used for drug discovery and toxicology studies for preclinical trials. In this study, zebrafish embryos were used to identify and characterize several candidate genes within two known regions of genomic instability on chromosome 18 and chromosome 4. This fish that were used in this study had been previously classified as genomic instability (gin) mutants due to increased incidence of somatic mutation …