Life Sciences Commons^™

The Effects Of Nesting Environment On Neonatal Hypoxic-Ischemic Injury, Laura Grace Rollins

Graduate Masters Theses

Term neonates with hypoxic-ischemic (HI) injury are at risk for devastating neurological sequelae. The objective of this study is to determine if altering the early environment for maternal care-taking impacts the immediate and long-term sequelae of HI offspring. The Rice-Vannucci model was used to induce HI in postnatal day (PND) 7 Long-Evans pups. Litters were assigned to a closed nest (CN) or normal standard housing (SH) condition. Neurobehavioral development, cognitive ability, and stress response were assessed to establish any benefits of the CN condition. Finally, postmortem brain tissue was analyzed for morphometric markers of injury.

Prenatal Programming Of Hepatic Glucose And Cholesterol Regulation In Male Rat Offspring By Chronic Intermittent Hypoxia, Waseem Iqbal

Electronic Thesis and Dissertation Repository

Obstructive sleep apnea (OSA) is a chronic disorder involving repetitive interruptions in breathing during sleep. Sufferers of OSA are exposed to chronic intermittent hypoxia (CIH), characterized by cyclical reductions in oxygen availability. A number of studies have established a link between OSA and various cardiovascular and metabolic comorbidities in adulthood, including hypertension, obesity, and type II diabetes. While the consequences of OSA in adults have been well described, the cross-generational impact of this condition and potential effects on fetal development are not known. Epidemiological and animal studies have demonstrated that physiological insults during pregnancy lead to diminished growth of offspring …

Investigating Potential Bioactive Compounds From Rhodococcus And Their Effects On Mcf7 Breast Cancer Cells, Megan N. Crabtree

Electronic Theses and Dissertations

Many drugs used in the treatment of various cancers are derived from or influenced by compounds from nature. The soil bacterium Rhodococcus is of interest because of its identified secondary metabolic pathways and the production of novel natural antibiotics from several strains. In this study, a solid agar extraction method was used to collect compounds from strains of Rhodococcus. These bacterial compound extracts were then tested using a MTT assay in order to evaluate their effectiveness in augmenting MCF7 breast cancer cell death. The results of two way ANOVA analyses revealed 18 compound extracts from 15 strains of Rhodococcus that …

Development Of Novel Subunit Vaccine Against H5n1 Influenza, Lu Zhang

Graduate Theses and Dissertations

Influenza is a common infectious disease resulting from a frequently mutated RNA virus. Vaccination is currently the most effective method to prevent people from seasonal or pandemic influenza. The production of traditional egg-based influenza vaccine is time-consuming and provides limited effect against new strains. Therefore, it is necessary to develop a rapid method to produce influenza vaccines. We proposed a novel influenza vaccine based on the E.coli expression system. Hemagglutinin (HA) is the major target surface protein of influenza virus for vaccine development. In this study, we sub-cloned the HAs encoding gene into an E. coli expression vector; the signal …

Investigation Of The Role Of Tor And Nutrient Restriction On Lifespan Of Arabidopsis Thaliana, Debashree Banerjee

Dissertations, Masters Theses, Capstones, and Culminating Projects

The Target of Rapamycin (TOR) kinase is evolutionarily conserved and is a key regulator, controlling many cellular functions to promote survival and growth in all eukaryotes. Several model organisms have indicated a relationship between TOR signaling and life expectancy, such as yeast, fruit flies and mice. Abundant nutrient availability promotes rapid growth and development, whereas depletion of nutrients reduces the activity of the pathways that are involved in growth and nutrient processing. This reduction in activity increases life expectancy, which is supported by evolutionary theories. The confirmed presence of the TOR homolog (a major regulator of growth and cell proliferation) …

Investigating Apoptosis Pathway In Chronic Lymphocytic Leukemia: Stromal Influence And Therapeutic Activation, Viralkumar M. Patel

Dissertations & Theses (Open Access)

Chronic lymphocytic leukemia (CLL) is a B-cell malignancy. High levels of Bcl-2 and IAP family proteins are responsible for apoptotic-resistance and accumulation of mature CLL lymphocytes in bone-marrow, lymph nodes and peripheral blood. Besides pro-survival proteins, supporting stromal cells as well as soluble factors in the microenvironment of bone-marrow and lymph nodes provide survival advantage to CLL leukemic cells.

Though the stromal – leukemia cell interactions has been studied extensively, in-depth-knowledge on the regulation of apoptotic pathway proteins in the context of microenvironment is still limited. To address this, the first part of our study focused on comprehensive analysis of …

C-Jun N-Terminal Kinases Regulate Adenovirus-Mediated Autophagy And Antigen Presentation, Sarah R. Klein

Dissertations & Theses (Open Access)

Targeted immunotherapy with recombinant, oncolytic adenoviruses is under investigation for the treatment of cancer. Evidence indicates adenoviruses induce autophagy that is required for oncolysis, but the molecular regulation of autophagy in infected cells remains under investigation. Our data suggested the canonical pathway regulating starvation-induced autophagy was not implemented in adenovirus-induced autophagy; however, adenovirus infection triggered phosphorylation of c-Jun N-terminal kinases (JNK) that was essential for autophagy. Adenoviral replication within the host cell elicited JNK pathway activation leading to B cell lymphoma-2 (Bcl-2) phosphorylation. JNK-dependent Bcl-2 phosphorylation stimulated the dissociation of Bcl-2/beclin 1 heterodimers, enabling beclin 1 to initiate autophagy. Moreover, …

The Development Of An In Vivo Microdialysis Collection Method Of Cytokines From Brain Tissue, Anthony W. Herbaugh

Graduate Theses and Dissertations

In this thesis, different methods to improve the microdialysis collection procedure for cytokines from brain tissue are presented. The first method was based on stopped flow and results indicating that no significant difference in relative recovery between stopped flow and continuous flow are shown. The second method is an antibody bead-based enhancement method. With the antibody bead-based method, a 3.5 fold increase in the collected concentrations of Chemokine (C-C motif) Ligand 2 (CCL2) were observed. However, there was no significant increase in the in vivo collection efficiency of Interleukin-6 (IL-6) using the antibody enhancement. Finally the development of an in-house …

Fgf4 Induced Wnt5a Gradient In The Limb Bud Mediates Mesenchymal Cell Directed Migration And Division, John C. Allen

Theses and Dissertations

The AER has a vital role in directing embryonic limb development. Several models have been developed that attempt to explain how the AER directs limb development, but none of them are fully supported by existing data. I provide evidence that FGFs secreted from the AER induce a gradient of Wnt5a. I also demonstrate that limb mesenchyme grows toward increasing concentrations of Wnt5a. We hypothesize that the changing shape of the AER is critical for patterning the limb along the proximal to distal axis. To better understand the pathway through which Wnt5a elicits its effects, we have performed various genetic studies. …

New Insights Into The Roles Of Human Dna Damage Checkpoint Protein Atr In The Regulation Of Nucleotide Excision Repair And Dna Damage-Induced Cell Death, Zhengke Li

Electronic Theses and Dissertations

Integrity of the human genome is frequently threatened by endogenous and exogenous DNA damaging reagents that may lead to genome instability and cancer. Cells have evolved multiple mechanisms to repair DNA damage or to eliminate the damaged cells beyond repair and to prevent diverse diseases. Among these are ataxia telangiectasia and Rad3-related (ATR)-mediated DNA damage checkpoint and nucleotide excision repair (NER) that are the major pathways by which cells handle ultraviolet C (UV-C)- or other exogenous genotoxin-induced bulky DNA damage. However, it is unclear how these 2 pathways may be coordinated. In this study we show that ATR physically interacts …

Endocannabinoid-Dependent Long-Term Depression Of Ventral Tegmental Area Gaba Neurons, Jared Mark Weed

Theses and Dissertations

GABA neurons in the ventral tegmental area of the midbrain are important components in the brain's reward circuit. Long term changes in this circuit occur through the process of synaptic plasticity. It has been shown that high frequency stimulation, as well as treatment with endocannabinoids, can cause GABA neurons in the ventral tegmental area to undergo long term depression, a form of synaptic plasticity that decreases excitability of cells. The present study elaborates on the mechanism whereby high frequency stimulation can result in long term depression of ventral tegmental area GABA neurons. Using the whole cell patch clamp technique in …

Involvement Of Ampk And Ap-1 Biochemical Pathways In Il-6 Regulation Of Steroidogenic Enzymes In The Adrenal Cortex, Matharage Shenali De Silva

Theses and Dissertations

The adrenal cortex is a crucial endocrine gland in the mammalian stress response. In chronic inflammatory stress, cortisol is elevated whereas adrenal androgens are decreased. Furthermore, ACTH levels have poor correlation with the plasma cortisol in these conditions, thus suggesting that other factors are driving the stress response during chronic inflammatory stress. Interleukin-6 (IL-6), a cytokine which is released during chronic inflammatory stress, is assumed to be one such factor. Thus the biochemical pathways by which IL-6 increases cortisol release from the zona fasciculata (ZF), and decreases adrenal androgen release from the zona reticularis (ZR) were investigated. Since IL-6 activates …

Ezh2 T416 Phosphorylation Enhances Breast Cancer Tumorigenesis, Adam M. Labaff, Adam M. Labaff

Dissertations & Theses (Open Access)

Enhancer of zeste homologue 2 (EZH2) is the catalytic subunit of Polycomb repressive complex 2 (PRC2) and catalyzes the trimethylation of histone H3 on lysine 27 (H3K27Me3), to repress gene transcription. Many types of cancer stem and progenitor cells, including breast, have demonstrated EZH2 to be fundamental in the biology and promoting the expansion of their cellular populations. How EZH2 regulates each of these respective tumor initiating cells (TICs) populations has been studied, but the signaling transduction mechanisms that regulate EZH2 in these TIC populations is yet to be elucidated. Phosphorylation of EZH2 by cyclin dependent kinases (CDK) has been …

Developmental And Molecular Functions Of Plakophilin-3, William A. Munoz

Dissertations & Theses (Open Access)

Plakophilin-3, the less studied member of the plakophilin-catenin subfamily, and the larger catenin family, binds directly to desmosomal cadherin cytoplasmic domains and enhances desmosome formation and stability. In mammals, plakophilin-3 is expressed at the highest levels in desmosome-enriched tissues such as epithelia, with the knock-out in mice producing corresponding reductions in ectodermal integrity. In tissue, cellular and intracellular contexts where plakophilin-3 is not at the desmosomal plaque, little is known about its functions in the cytoplasm or nucleus, where it also localizes.

My work employed embryos of the amphibian, Xenopus laevis, to examine plakophilin-3’s developmental roles. I first evaluated …

Protective Effects Of Sphingomyelin Against Uv Photodamage In Human Keratinocytes, Kathleen De Guzman

Master's Theses

Ultraviolet (UV) radiation has been demonstrated in numerous studies to be a major risk factor for non-melanoma skin cancer development. Despite the emergence of current UV-preventative strategies, such as sunscreens and skin-protective clothing, the incidence of non-melanoma skin cancer has continued to rise. This has encouraged investigations on alternative methods for UV prevention. In particular, bovine milk sphingomyelin has been studied for its potential in protecting human skin against UV photodamage. While the previous studies have suggested that sphingomyelin exhibits UV-protective properties in a human skin equivalent model, the exact mechanisms behind sphingomyelin’s photoprotective effects are yet unknown.

This thesis …

Transforming Growth Factor-Beta Receptor Signalling Is Modulated By Integrin-Linked Kinase, Stellar H. Boo

Electronic Thesis and Dissertation Repository

Transforming growth factor-beta 1 (TGF-β1) modulates regeneration after injury through induction of fibroblast proliferation, migration, and differentiation into myofibroblasts. Induction of myofibroblast differentiation by TGF-β1 requires expression of integrin-linked kinase (ILK). I now show that ILK interacts with TGF-β receptor type II (TβRII) in primary dermal fibroblasts. Further, colocalization of ILK and TβRII can be observed at the cell membrane and in intracellular vesicles. The association of TβRII and ILK does not require TGF-β1 stimulation, kinase activity of TGF-β1 receptor type I or TβRII, and it does not involve interactions between ILK and focal adhesion-associated proteins. When this interaction is …

The Mechanism Of The Gastric Epithelial Stem Cell Response To Metaplastic Injury, Shradha Sachin Khurana

All Theses and Dissertations (ETDs)

Almost nothing is known about the identity of the epithelial stem cell of the gastric corpus, either during normal turnover or in response to injury. Our lab has shown that injection of the selective estrogen receptor modulator tamoxifen leads to near complete atrophy of parietal cells by 3 days and induces expansion of an undifferentiated cell population within the normal stem cell niche in the isthmus of the gastric unit. Here we show that CD44 labels the membranes of such undifferentiated isthmal cells, both in the normal gastric epithelium and when those cells expand fourfold upon injury with tamoxifen. Loss …

Measuring And Modeling The Response Characteristics Of The Environmental Phosphate Transducer In Escherichia Coli, Chetan Sood

Open Access Dissertations

The PhoR/PhoB two-component system in Escherichia coli is a biological transducer that senses the limitation of environmental inorganic orthophosphate, the bacteria's preferred source of the essential nutrient phosphate, and transmits that information to the interior of the cell initiating a response that mitigates phosphate starvation. In the first part of this study, we present and apply a fluorescence microscopy technique to measure, in vivo, the dynamic response characteristics of the transducer with single-cell resolution. We report that the transience in the PhoR/PhoB TCS response is consistent with the transducer having a threshold sensitivity to the concentration of environmental phosphate, …

Establishing The Role Of The Pancreatic Transcription Factor Mist1 In Xbp1-Mediated Maintenance Of Pancreatic Acinar Cell Homeostasis, David Alan Hess

Open Access Dissertations

Pancreatic acinar cells (PACs) continuously produce more protein than any other cell type in the human body. As a result, PACs and other specialized secretory cells have a constant demand placed on their protein synthetic and packaging machinery. When demand for secreted products exceeds the capacity of the cell's basal protein production facilities, dangerous accumulations of misfolded proteins can build up, resulting in a condition known as ER stress. To ameliorate this stress, secretory cells activate a coordinated, three-part compensatory network collectively known as the unfolded protein response (UPR) to both expand the capacity of the ER and directly assist …

Developmental Characterization Of Tissue Inhibitor Of Metalloproteinase Domain Functions In Xenopus Laevis, Michelle A. Nieuwesteeg

Electronic Thesis and Dissertation Repository

During development the extracellular matrix is cleaved and remodeled to facilitate the large-scale cell rearrangements that are necessary for processes like gastrulation, neurulation, angiogenesis and organogenesis. ECM remodeling occurs primarily through secreted enzymes called matrix metalloproteinases (MMPs). Regulation of MMP activity is achieved through the tissue inhibitor of metalloproteinases (TIMPs), a small family of secreted proteins that bind MMPs in a 1:1 manner to inhibit their activity. Although TIMPs were originally characterized based on their MMP-inhibitory activities, in vitro studies have revealed that TIMPs are multifunctional proteins, with structurally and functionally distinct N- and C-terminal domains. TIMP N-terminal domains bind …

The Role Of Ykl-40 In The Progression Of Glioblastoma, Ralph Anthony Francescone

Open Access Dissertations

Glioblastoma Multiforme (GBM) is the most common brain cancer and one of the most fatal forms of cancer overall. The average survival time is 10-14 months, and less than 10% of patients survive more than 5 years after diagnosis. It is characterized by extreme vasculature, chemo/radioresistance, and invasiveness into the normal brain. The current standard of care, which includes surgical removal of tumor, radiation, and the chemotherapeutic agent temozolomide, initially stunt tumor growth. Nevertheless, the tumor invariably rebounds and the patient succumbs to the disease. Therefore, there is an urgent need to develop new therapies for this devastating disease.

YKL-40 …

Effects Of Phytochemicals From Rhodiola Crenulata On Highly Invasive Breast Cancer Cell Lines And Embryonic Models Of Migration, Adaris Rodriguez-Cortes

Open Access Dissertations

The root of the Tibetan plant Rhodiola crenulata is part of eastern traditional medicine. Studies have suggested that members of the Rhodiola genus display anticancer properties. In this study we examine the effect of R. crenulata in a cellular model of invasive breast cancer, this disease being the second cause of cancer death among women in the US. Deregulation of the Wnt/β-catenin pathway has been frequently observed in breast cancers and appears to have a key role in the transformation of benign cells to a malignant form. Although mutations of the Wnt growth factor are rarely observed in cancer, the …

Analysis Of Subcellular Localization Patterns Suggest Non-Enzymatic Roles For Select Arogenate Dehydratases, Travis R. Howes

Electronic Thesis and Dissertation Repository

The final step of phenylalanine biosynthesis in planta is catalyzed by arogenate dehydratases (ADTs). Previously cloned ADT-CFP fusion genes were used to provide an in depth study of the subcellular localization of all six ADTs from Arabidopsis thaliana. Through co-localization of ADT-CFPs with a stroma-marker it is shown that most ADTs localize to stroma-filled projections from chloroplasts called stromules. The localization of ADT5 and ADT2 provide evidence for additional, non-enzymatic roles. In the case of ADT5, it is found to localize to the nucleus, suggestive of an uncharacterized nuclear role. The localization patterns of ADT2 are suggestive of a …

Cx43 Reduces Melanoma Growth Within A Keratinocyte Microenvironment And During Tumorigenesis In Vivo, Mark J. Ableser

Electronic Thesis and Dissertation Repository

Connexins have been frequently identified as tumor suppressors in many cancers, however, their role in melanoma tumorigenesis remains controversial. Here, we show that B16-BL6 mouse melanoma cells express low levels of Cx26 and Cx43, rendering them gap junctional intercellular communication (GJIC) deficient. Following ectopic expression of Cx26 and Cx43, gap junction-like plaques were evident at the cell surface and the incidence of dye transfer was significantly increased similar to connexin-rich keratinocytes. The expression of Cx43, but not Cx26, significantly reduced proliferation and anchorage-independent growth relative to controls, whereas migration was unaffected. Additionally, Cx43-expressing melanoma cells displayed significantly reduced growth amongst …

Exploring Tissue Engineering: Vitamin D3 Influences On The Proliferation And Differentiation Of An Engineered Osteoblast Precursor Cell Line During Early Bone Tissue Development, Shelley S. Mason

Dissertations and Theses

Most of the load-bearing demand placed on the human body is transduced by skeletal tissue, and the capacity of the skeleton to articulate in various opposing directions is essential for body movement and locomotion. Consequently, cartilage and bone defects due to trauma, disease, and developmental abnormalities result in disabling pain and immobility for millions of people worldwide. A novel way of promoting cartilage and bone regeneration is through the incorporation of either primary cells or multipotent progenitor cells in a three-dimensional (3D) biomaterial scaffold, and/or the addition of exogenous growth and differentiation factors. The first part of this study reports …

Shroom3 Deficient Mice Show Congenital Heart Defects, Rami R. Halabi

Electronic Thesis and Dissertation Repository

Congenital heart defects (CHDs) are associated with a number of genetic and environmental risk factors affecting approximately 1% of newborns. Shroom3 is an actin binding and microtubule organizing protein essential for neural tube closure in mouse, Xenopus and chick. In Xenopus shroom3 expression is found within the forming heart and loss of activity results in malformed hearts. In addition, SHROOM3 has recently been associated with heterotaxy in a human patient. Mice homozygous for the Shroom3 gene trap die at birth due to exencephaly and here, I provide evidence that the majority of these mice have CHDs, including septal defects, semilunar …

Chromatin Insulators: Master Regulators Of The Eukaryotic Genome, Todd Andrew Schoborg

Doctoral Dissertations

Proper organization of the chromatin fiber within the three dimensional space of the eukaryotic nucleus relies on a number of DNA elements and their interacting proteins whose structural and functional consequences exert significant influence on genome behavior. Chromatin insulators are one such example, where it is thought that these elements assist in the formation of higher order chromatin loop structures by mediating long-range contacts between distant sites scattered throughout the genome. Such looping serves a dual role, helping to satisfy both the physical constraints needed to package the linear DNA polymer within the small volume of the nucleus while simultaneously …

Developmental Expression Profile Of Bric Á Brac 2, Midline And H15 In The Developing Eye And Central Nervous System Of Drosophila Melanogaster, Petra Visic

Honors Theses

Aberrant activity of a single gene can lead towards development of cancerous cells. Drosophila melanogaster is a useful model system to study cancer because there is high degree of evolutionary conservation in signaling pathways between humans and flies that play major roles in regulating cell proliferation and growth (Miles et al., 2011). At The University of Southern Mississippi (USM), Dr. Leal’s lab has gathered evidence suggesting that bab1 and bab2 interact with the T-box gene midline (mid) and its paralog H15, while the early developmental function of bab1 and bab2 remains unknown. That is why elucidating the early …

Identification Of Actin Cytoskeletal Protein Interactions With The Fission Yeast Scaffold, Mid1, Marian Testori

Masters Theses

Cancer is a disease of uncontrolled cell division. Cell division in eukaryotic cells occurs by the formation of a contractile ring, predominantly composed of filamentous actin (F-actin). During mitosis, actin filaments polymerize to form rings at the medial plane of the cell that constrict causing the cell membrane to pinch and divide. Proteins that regulate this process are essential because dysregulation can lead to uninhibited cell growth and division. In fission yeast, the protein Mid1 functions as a scaffold to recruit regulatory proteins required for actin filament formation and simultaneously anchors the contractile ring at the cell division site. The …

Characterization Of A Glycosyphosphatidylinositol Anchor Transamidase In Arabidopsis Thaliana And The Function Of Gpi Anchored Proteins In Stomatal Development, Mark Gerald Ronald Bundy

Masters Theses

In plants stomata play a vital role for survival by allowing the gas exchange of CO₂ [carbon dioxide] and water vapor to occur. A stoma is a central pore flanked by two kidney shaped guard cells and in wild type there is at least one pavement cell between each stoma. The ERECTA (ER) gene family consisting of ER, ERL1, ERL2 is involved in regulation of stomata development, where a triple mutant of er erl1 erl2 displays an increased stomata index and clusters of stomata that disobey the one cell spacing rule. To better understand the pathway of stomata development, …