Developmental Biology Commons^™

Development Of Peripheral Innervation In The Frog Xenopus Laevis, Mitali A. Gandhi

Theses and Dissertations

The skin in Xenopus laevis is innervated by two different sets of mechanosensory neurons at different times during development. Rohon Beard (RB) neurons start differentiating during gastrulation, innervate the embryonic skin and mediate sensory function during hatching. Dorsal Root Ganglion (DRG) neurons start differentiating after neural crest migration, innervate adult epidermal targets and mediate mechanosensory function during larval and adult stages and eventually replace RB neurons. The change in sensory neurons occurs during the transformation of skin, sensory structures, and behavior from their embryonic to their larval forms. We hypothesized that developmental changes in either the sensory end organs or …

Role Of Msaa Gene In Regulation Of The Msaabcr Operon And Biofilm Development In Staphylococcus Aureus, Ahmed Alzuway

Master's Theses

Staphylococcus aureus is an important human pathogen that causes wide variety of diseases ranging from chronic biofilm associated infection to acute life threatening infection such as bacteremia, pneumonia, osteomyelitis, or endocarditis, despite the progress with antibiotics used in the treatment of bacterial infections. Furthermore, increased use of prosthetic and indwelling devices in modern medical practices has led to increased infections due to S. aureus. Treating S. aureus infections have become difficult owing to its ability to resist most of the antibiotics; this problem is further exacerbated by ability of MRSA strains to form biofilms. Emergence of community-acquired methicillin resistance …

Zebrafish As A Model For Determining The Mechanisms Causing Deafness In Myh9-Related Disease, Luke David Spychalla

Theses and Dissertations

Approximately 1 in 500 infants are diagnosed with hearing loss, and about half of these cases can be traced to genetic defects. Several hundred genes have been implicated in deafness, including MYH9, which codes for the conventional motor protein non-muscle myosin IIA (NMIIA). Mutations in MYH9 lead to syndromic MYH9-related diseases, which include deafness as a variable symptom, as well as non-syndromic autosomal deafness DFNA17. Despite its identification as a deafness gene, the functions of MYH9 in ear development and hearing remain unknown. To study this role, we will use zebrafish as a model. Zebrafish offer significant advantages including established …

Ngn3 Expression In Definitive Endoderm Progenitors Specifies Pancreatic Endocrine Precursors, Ahmed Shah

Electronic Thesis and Dissertation Repository

Our lab previously demonstrated that expression of the lineage-determining transcription factor SOX17 in human embryonic stem cells was sufficient to specify stable definitive endoderm progenitors (DEPs). The current study was aimed at generating pancreatic precursors from SOX17-DEPs through controlled expression of the transcription factor NGN3. We generated hESC lines with inducible SOX17 and NGN3 and compared the effects of high and low levels of NGN3 expression. NGN3 expression in DEPs induced markers of pancreatic differentiation (PAX4, PAX6, NKX6.1, ISL1). While high NGN3 expression induced the β cell marker PDX1, low NGN3 expression induced the δ cell markers (CCK_BR, …

Lateral Line Analogue Aids Vision In Successful Predator Evasion For The Brief Squid, Lolliguncula Brevis, Carly A. York, Ian K. Bartol

Biological Sciences Faculty Publications

Cephalopods have visual and mechanoreception systems that may be employed to sense and respond to an approaching predator. While vision presumably plays the dominant role, the importance of the lateral line analogue for predator evasion has not been examined in cephalopods. To test the respective roles of vision and the lateral line analogue, brief squid, Lolliguncula brevis, were observed in the presence of summer flounder, Paralichthys dentatus, under light and dark conditions with their lateral line analogue intact and ablated. Hair cell ablation was achieved through a pharmacological technique used for the first time on a cephalopod. The …

Ontogenetic Investigation Of Underwater Hearing Capabilities In Loggerhead Sea Turtles (Caretta Caretta) Using A Dual Testing Approach, Ashley L. Lavender, Soraya M. Bartol, Ian K. Bartol

Biological Sciences Faculty Publications

Sea turtles reside in different acoustic environments with each life history stage and may have different hearing capacity throughout ontogeny. For this study, two independent yet complementary techniques for hearing assessment, i.e. behavioral and electrophysiological audiometry, were employed to (1) measure hearing in post-hatchling and juvenile loggerhead sea turtles Caretta caretta (19-62 cm straight carapace length) to determine whether these migratory turtles exhibit an ontogenetic shift in underwater auditory detection and (2) evaluate whether hearing frequency range and threshold sensitivity are consistent in behavioral and electrophysiological tests. Behavioral trials first required training turtles to respond to known frequencies, a multi-stage, …

Vitamin A Deficiency Causes Ovulation Abnormalities In Mice, Rebecca Ursin

DePaul Discoveries

Retinoic acid (RA) is an active metabolite of vitamin A (VA) and is involved in tissue organization, patterning, and growth. RA has been shown to regulate male reproduction, however information on its role in ovary development is limited. To investigate the functions of RA in the ovary, we examined its role in ovary development and ovulation using an in vivo dietary VA-deprivation animal model. Our preliminary results have shown that VA deficiency causes a variety of ovarian pathologies, including reduced numbers of total follicles and corpus lutea, formation of hemorrhagic and atretic follicles, and formation of bursa and follicular cysts. …

Determining The Potential Activity Of Wnt Signaling During Zebrafish Oocyte Maturation, Nathan Pincus

Honors Program Theses

During maturation, the oocyte (immature egg) progresses from prophase I to metaphase II of meiosis and a multitude of cellular changes occur. In zebrafish, oocyte maturation is triggered by 17α,20β-dihydroprogesterone (DHP), which binds to a membrane-bound receptor, however the extent of communication between the oocyte and its environment is not fully understood. Wnt signaling pathways are known to regulate gene expression, cell behavior, cell adhesion, and cell polarity, as well as play an essential role in embryonic development. In this study, I investigated the potential activity of Wnt signaling pathways during zebrafish oocyte maturation by examining the gene expression of …

Role Of Nitric Oxide In Embryonic Heart Development And Adult Aortic Valve Disease, Yin Liu

Electronic Thesis and Dissertation Repository

Congenital heart disease (CHD) is the most common birth defect in infants. Identifying factors that are critical to embryonic heart development or CHDs in general could further our understanding of the disease and may lead to new strategies of its prevention and treatment. Endothelial nitric oxide synthase (NOS3/eNOS) is known for many important biological functions including vasodilation, vascular homeostasis and angiogenesis. Previous studies have shown that deficiency in NOS3 results in congenital septal defects, cardiac hypertrophy and postnatal heart failure. In addition, NOS3 is pivotal to morphogenesis of aortic valve and myocardial capillary development. The aim of my thesis was …

Transcriptome Analysis Of Sea Lamprey Embryogenesis, Zakary Ilya Yermolenko

Seton Hall University Dissertations and Theses (ETDs)

The sea lamprey (Petromyzon marinus) has survived throughout evolution for hundreds of millions of years. It is considered an invasive species to the Great Lakes that has caused dramatic changes in the ecosystem for fish communities resulting in the collapse of a fishing industry that was previously valued at billions of dollars. Successful management of the sea lamprey is essential to a sustainable fishing industry and biodiversity. Therefore sea lamprey embryos were studied at various stages of development by growing them in a simulated habitat. RNAs from adult female ovaries and embryos at different time points during embryogenesis …

P53 Maintains Hepatic Cell Identity During Liver Regeneration, Zeynep Hande Coban Akdemir

Dissertations & Theses (Open Access)

p53 MAINTAINS HEPATIC CELL IDENTITY DURING LIVER REGENERATION

Zeynep Hande Coban Akdemir, B.S.,M.A.

Advisory Professor: Michelle Craig Barton, Ph.D.

p53 is a tumor suppressor that has been well studied in tumor-derived, cultured cells. However, its functions in normal proliferating cells and tissues are generally overlooked. We propose that p53 functions during the G1-S transition can be studied in normal, differentiated cells during surgery-induced liver regeneration. Two-thirds partial hepatectomy (PH) of mouse liver offers a unique model to compare p53 functions in regenerating versus sham (control) cells. My hypothesis is that intersection of global expression analyses (microarray and RNA sequencing) and …

Functional Study Of The Suppressor Of Hairy-­Wing Insulator Protein In Drosophila Melanogaster, Shih-Jui Hsu

Doctoral Dissertations

Eukaryotic chromatin insulators play an essential role in regulating gene expression and modifying nuclear architecture by organizing the higher-order chromatin structure in response to cellular and developmental cues. The details on how insulators function in this capacity are not completely understood.

Five different types of insulators have been identified in Drosophila. Each functional insulator consists of an insulator DNA response element bound by an insulator protein, which recognizes specific DNA sequences. Each type of insulator functions individually as well as collaboratively. Except for the Su(Hw) insulator protein, the other insulator proteins are necessary for viability considering loss of Su(Hw) …

Regulation Of Mammary Gland Development And Tumorigenesis By 14-3-3 Zeta, Sumaiyah Rehman

Dissertations & Theses (Open Access)

Signaling pathways that play critical roles in organ development are often aberrantly regulated during cancer initiation and progression. 14-3-3z is overexpressed in more than 40% of breast cancers and is associated with poor patient prognosis. Therefore, the function of 14-3-3z in cancer and normal mammary gland development was investigated utilizing multiple in vivo and in vitro approaches. 14-3-3z is a chaperone protein that interacts with a multitude of oncogenes and tumor suppressor genes, thereby functioning as a critical node in multiple oncogenic signaling networks. Mammary gland-specific 14-3-3z transgenic mouse models showed that 14-3-3z overexpression was sufficient to induce mammary tumorigenesis. …

Characterization Of Ftsa-Ftsn Interaction During Escherichia Coli Cell Division, Kimberly.Busiek@Gmail.Com K. Busiek

Dissertations & 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 …

Transcriptomic Insights Into The Diplontic Life History Of Diatoms, Colton Richard Kessenich

Graduate Theses and Dissertations

An organism's life cycle is the direct result of its evolutionary history and represents a fundamental aspect of its ancestry and ecology. Yet the process of linking alternating life-history stages has proven to be challenging, if not impossible in some cases. Diatoms (Bacillariophyceae) are no exception to this challenge, and their diversity of life stages and reproductive strategies add further challenges. A central focus of diatom research has been to unravel the evolutionary events that led to their extraordinary diversity, a line of inquiry that has been greatly aided by the availability of next-generation sequence data. Yet without proper taxonomic …

Investigating The Co-Regulatory Role Of Midline And Extramacrochaetae In Regulating Eye Development And Vision In Drosophila Melanogaster, Lillian M. Forstall

Honors Theses

The Honors thesis research focused on the roles of extramacrochaetae and midline in regulating eye development and the vision of Drosophila melanogaster. It is known from previous studies that extramacrochaetae (emc) and midline (mid) independently regulate the formation of ommatidial units in the Drosophila compound eye. However, the thesis focuses on the interaction of these two genes and their co-dependent roles in regulating eye development. This study also attempts to explain the recovered formation of ommatidial units and interommatidial bristles when the expression of both of these genes is reduced and whether flies doubly mutant …

The Grass Shrimp, Palaemonetes, Pugio: Hypoxic Influences On Embryonic Development, Christensen C. Javier

UNLV Theses, Dissertations, Professional Papers, and Capstones

Grass shrimp,Palaemonetes pugio, can survive in brackish waters and estuarine ecosystems despite the frequent oscillations and fluctuations in salinity, temperature and oxygen. AdultP. pugiohave the ability to osmoregulate (Romney and Reiber 2011), change cardiac parameters to tolerate temperatures (not yet published, Mika and Reiber) and oxyregulate (Guadagnoli and Reiber 2013). Manipulation of cardiac parameters allows for these methods of regulation. However, cardiac contraction and internal convection of oxygen do not occur until later stages of embryonic development. Studies focused on these morphological and physiological advantages may provide further understanding of the regulatory mechanisms within grass shrimp embryos, larvae and adults. …

Maternal Control Of Genomic Imprinting: Effects Of Infertility And Ovarian Stimulation In A Mouse Model, Michelle M. Denomme

Electronic Thesis and Dissertation Repository

Gametogenesis and early embryogenesis are important stages in which genome-wide epigenetic transitions required for early mammalian development are orchestrated. This is exemplified by the occurrence of genomic imprinting, where epigenetic mechanisms lead to the monoallelic expression of a subset of genes. Parental-specific DNA methylation in the gametes results in the distinct nonequivalence of the parental genomes in the early embryo. Changes from normal gamete and embryo development by impaired fertility or assisted reproductive technologies (ARTs) may disrupt the processes of imprint acquisition and imprint maintenance. My hypothesis is that aberrant imprinted methylation arises from impaired maternal fertility or ovarian stimulation …

Signaling Events During Extraembryonic Endoderm Differentiation, Jason Taek Ki Hwang

Electronic Thesis and Dissertation Repository

Mouse F9 cells differentiate into primitive endoderm (PrE) when treated with retinoic acid (RA) and into parietal endoderm (PE) following subsequent treatment with dibutyryl cAMP. Wnt6 is up-regulated in PrE cell, and although it is sufficient to induce differentiation by signaling through the canonical WNT/β-catenin pathway, the mechanism by which the Wnt6 gene is regulated is not known. In addition to WNT signaling, PrE differentiation is accompanied by an increase in reactive oxygen species (ROS). ROS have been implicated in regulating the canonical WNT/β-catenin signaling pathway through Nucleoredoxin (NRX), but whether they are sufficient to induce extraembryonic endoderm in vitro …

Photobiostimulation In C. Elegans As A Model For Low Level Light Therapy, Michael J. Spoto, Daryl D. Hurd

Science Scholars

Low-Level Laser Therapy (LLLT) is a developing therapeutic technique that has been gaining recognition in the scientific community in recent years. Previous experiments performed in LLLT research projects have been primarily mammalian and cell culture based. These experiments have produced results showing accelerated tissue repair. In this experiment, we introduce a new model, Caenorhabitidis elegans, a free-living soil nematode, to be used in LLLT research by testing the effects of exposure of the organism to various wavelengths and intensities of light commonly used in LLLT. C. elegans was shown to respond to photobiostimulation when exposed to specific wavelengths of …