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Physiological Characterization Of Prochlorococcus Under Abiotic Stressors Temperature And Hydrogen Peroxide, Lanying Ma Dec 2015

Physiological Characterization Of Prochlorococcus Under Abiotic Stressors Temperature And Hydrogen Peroxide, Lanying Ma

Doctoral Dissertations

Cyanobacteria of the genus Prochlorococcus are the smallest and most abundant phytoplankters in the ocean. Temperature is a major influence on Prochlorococcus abundance and distribution in the ocean, but the physiological basis for this relationship is not well understood. In other microbes, lipid and fatty acid composition have been shown to be influenced by temperature, and temperature has also been proposed as a relevant factor for setting the elemental allocation in marine phytoplankton. In this study, we found that percentage of fatty acids unsaturation was negatively related with temperature in some Prochlorococcus strains, but this was not universal. Temperature had …


Health Assessment Of Two Reintroduced Populations Of American Martens (Martes Americana) In Michigan, Maria Catherine Spriggs Dec 2015

Health Assessment Of Two Reintroduced Populations Of American Martens (Martes Americana) In Michigan, Maria Catherine Spriggs

Doctoral Dissertations

The American marten (Martes americana) was extirpated from Michigan during the early-20th century due to loss of vast areas of mature conifer forest and unregulated trapping. The species was reintroduced into the Upper Peninsula (UP) and Northern Lower Peninsula (NLP) during the mid-20th century. While the American marten population in the UP has grown and is doing well, the population in the NLP has been less successful. The reasons for the limited success of the NLP population are unknown, but may include lack of suitable habitat, limited reproductive success, poor genetic diversity, disease, or negative environmental impacts. American …


Systematics And Diversification Patterns Of Morphologically And Ecologically Diverse Lineages Of Agaricomycetes: Clavariaceae And Cantharellales, Joshua Mark Birkebak Dec 2015

Systematics And Diversification Patterns Of Morphologically And Ecologically Diverse Lineages Of Agaricomycetes: Clavariaceae And Cantharellales, Joshua Mark Birkebak

Doctoral Dissertations

The recent advent of molecular tools and methods to understand the diversity of living organisms allows for exploration of former untestable theories concerning the diversity of fungi. Here we assess the morphologically based classification of the family Clavariaceae in light of molecular phylogenetic reconstruction and propose a revised classification base on natural assemblages. We used stable isotope ratios to uncover a biotrophic nutritional mode for much of the family, which had not been well understood historically. We also investigate several enigmatic lineages of agaricoid or cantharelloid fruiting body producing fungi within a clade of otherwise clavarioid fruiting bodies. We provide …


Linking Physiology And Biogeography: Disentangling The Constraints On The Distributions Of Ant Species, Lacy Danikas Chick Dec 2015

Linking Physiology And Biogeography: Disentangling The Constraints On The Distributions Of Ant Species, Lacy Danikas Chick

Doctoral Dissertations

Understanding the factors that limit the distribution of species is at the core of ecological and biogeographical research, and is critical if we are to predict the responses of key ecosystem components to ongoing climatic changes. My doctoral research seeks to provide an understanding of how thermal physiology influences species’ distributions and better define the mechanisms underlying geographic variation in biodiversity. By using natural temperature gradients (both elevational and latitudinal) and coupling controlled laboratory experiments with field observations and null modeling approaches, I was able to document the role of inter-specific variation in thermal physiology and, more interesting, inter-population variation …


Molecular Breeding Strategies For Improvement Of Complex Traits In Soybean, Christopher Joseph Smallwood Dec 2015

Molecular Breeding Strategies For Improvement Of Complex Traits In Soybean, Christopher Joseph Smallwood

Doctoral Dissertations

Soybean [Glycine max (L.) Merrill] is the leading oilseed crop grown in the world. Yield, fatty acids, protein, and oil are commercially important soybean traits; thus evaluation of breeding strategies for improvement of these traits is merited. To accomplish this, a comparison of molecular and phenotypic breeding strategies from progeny row selections was performed. From this it was determined that molecular strategies consistently outperformed phenotypic selections (PS) in the progeny row stage for soybean yield, fatty acids, protein, and oil. For yield, Epistacy was the preferred selection method. For fatty acids, protein, and oil, the genomic selection (GS) strategies were …


Multipartite Graph Algorithms For The Analysis Of Heterogeneous Data, Charles Alexander Phillips Dec 2015

Multipartite Graph Algorithms For The Analysis Of Heterogeneous Data, Charles Alexander Phillips

Doctoral Dissertations

The explosive growth in the rate of data generation in recent years threatens to outpace the growth in computer power, motivating the need for new, scalable algorithms and big data analytic techniques. No field may be more emblematic of this data deluge than the life sciences, where technologies such as high-throughput mRNA arrays and next generation genome sequencing are routinely used to generate datasets of extreme scale. Data from experiments in genomics, transcriptomics, metabolomics and proteomics are continuously being added to existing repositories. A goal of exploratory analysis of such omics data is to illuminate the functions and relationships of …


Brown And Beige Adipocytes: Effects Of Inflammation And Nutritional Intervention, Jiyoung Bae Dec 2015

Brown And Beige Adipocytes: Effects Of Inflammation And Nutritional Intervention, Jiyoung Bae

Doctoral Dissertations

Recent findings of brown adipocytes and brown-like or beige adipocytes, capable of dissipating energy as heat, in adult humans have promised new hope for obesity treatment and prevention. Understanding of the regulation of brown and beige adipocytes will provide novel strategies to reach the goal. Pattern recognition receptors (PRR) are responsible for inflammation in adipose tissue, which leads to adipose dysfunction and obesity associated chronic diseases. It has been shown that PRR activation induces inflammation, leading to insulin resistance in white adipocytes and white adipose tissue (WAT). However, the roles of PRR activation in brown adipocytes and brown adipose tissue …


Application Of Hidden Markov Model Based Methods For Gaining Insights Into Protein Domain Evolution And Function, Amit Anil Upadhyay Dec 2015

Application Of Hidden Markov Model Based Methods For Gaining Insights Into Protein Domain Evolution And Function, Amit Anil Upadhyay

Doctoral Dissertations

With the explosion in the amount of available sequence data, computational methods have become indispensable for studying proteins. Domains are the fundamental structural, functional and evolutionary units that make up proteins. Studying protein domains is an important part of understanding protein function and evolution. Hidden Markov Models (HMM) are one of the most successful methods that have been applied for protein sequence and structure analysis. In this study, HMM based methods were applied to study the evolution of sensory domains in microbial signal transduction systems as well as functional characterization and identification of cellulases in metagenomics datasets. Use of HMM …


Bacterial Diversity And Function Within An Epigenic Cave System And Implications For Other Limestone Cave Systems, Kathleen Merritt Brannen-Donnelly Dec 2015

Bacterial Diversity And Function Within An Epigenic Cave System And Implications For Other Limestone Cave Systems, Kathleen Merritt Brannen-Donnelly

Doctoral Dissertations

There are approximately 48,000 known cave systems in the United States of America, with caves formed in carbonate karst terrains being the most common. Epigenic systems develop from the downward flow of meteoric water through carbonate bedrock and the solutional enlargement of interconnected subsurface conduits. Despite carbonate karst aquifers being globally extensive and important drinking water sources, microbial diversity and function are poorly understood compared to other Earth environments. After several decades of research, studies have shown that microorganisms in caves affect water quality, rates of carbonate dissolution and precipitation, and ecosystem nutrition through organic matter cycling. However, limited prior …


Applications Of Evolutionary Bioinformatics In Basic And Biomedical Research, Ogun Adebali Dec 2015

Applications Of Evolutionary Bioinformatics In Basic And Biomedical Research, Ogun Adebali

Doctoral Dissertations

With the revolutionary progress in sequencing technologies, computational biology emerged as a game-changing field which is applied in understanding molecular events of life for not only complementary but also exploratory purposes. Bioinformatics resources and tools significantly help in data generation, organization and analysis. However, there is still a need for developing new approaches built based on a biologist’s point of view. In protein bioinformatics, there are several fundamental problems such as (i) determining protein function; (ii) identifying protein-protein interactions; (iii) predicting the effect of amino acid variants. Here, I present three chapters addressing these problems from an evolutionary perspective. Firstly, …


Epidemiology Of Select Species Of Filarial Nematodes In Free-Ranging Moose (Alces Alces) Of North America, Caroline Mae Grunenwald Dec 2015

Epidemiology Of Select Species Of Filarial Nematodes In Free-Ranging Moose (Alces Alces) Of North America, Caroline Mae Grunenwald

Doctoral Dissertations

North American moose (Alces alces) are a culturally and economically valued species. Recent population declines raise concern for the survivability of this natural resource. The Minnesota population has experienced the most dramatic decline, with a 60% loss in total numbers since 2006. Nematode parasites, particularly some species of filarids, are important pathogens of moose and could be contributing to morbidity and mortality. This study investigates the eco-epidemiology of two filarial parasites of moose: Rumenfilaria andersoni and Elaeophora schneideri. By surveying cervid species from six U.S. states, we discovered R. andersoni was present in moose from all sample locations …


Evaluation Of Reproductive Efficiency In Lactating Dairy Cows Through Physiologic Evaluation And Synchronization Modification, Charles Dexter Young Dec 2015

Evaluation Of Reproductive Efficiency In Lactating Dairy Cows Through Physiologic Evaluation And Synchronization Modification, Charles Dexter Young

Doctoral Dissertations

Reproductive performance of lactating dairy cows has decreased as milk production has increased as a result of genetic selection. Milk production alone is not the reason for decreased reproductive performance, as fertility issues are multifactorial and collaborative. Research chapters contained within have taken an applied approach focusing in two different areas of fertility. One approach was development of an evaluation system to identify lactating cows with decreased fertility prior to breeding; while another approach was to modify an ovulation synchronization protocol during periods of heat stress in order to improve fertility. The first focus was development and evaluation of a …


Biotransformation Of Polymethoxyflavones By Gut Microbiome And Molecular Characterization Of Polymethoxyflavones By Surface Enhanced Raman Spectroscopy, Changchu Ma Nov 2015

Biotransformation Of Polymethoxyflavones By Gut Microbiome And Molecular Characterization Of Polymethoxyflavones By Surface Enhanced Raman Spectroscopy, Changchu Ma

Doctoral Dissertations

Polymethoxyflavones (PMFs), a unique class of flavonoids found in citrus fruits has shown beneficial bioactivities. Biological fate of PMFs in the gastrointestinal tract is critical for their bioactivities. PMFs can be biotransformed to produce various metabolites with different bioactivities, and PMFs can also interact with the food matrix, which in turn affects their bioactivities. Therefore, we investigated the biotransformation of two PMFs, namely nobiletin (NBT) and 5-hydroxylnobiletin (5HN) by the gut microbiome. Mice were fed with NBT or 5HN, and small intestinal contents were collected and subjected to anaerobic fermentation by gut microbiome isolated from mice and human volunteers. HPLC …


The Chemopreventive Effect Of Polymethoxyflavones: Targeting The Colorectal Cancer Stem Cells, Fei Xu Nov 2015

The Chemopreventive Effect Of Polymethoxyflavones: Targeting The Colorectal Cancer Stem Cells, Fei Xu

Doctoral Dissertations

Among all the cancers, the death rate of colorectal cancer is one of the highest. Evidence from both murine xenograft model and human trials have shown cancer stem cells (CSCs) are responsible for the initiation, metastasis and recurrence of multiple cancers therefore targeting colorectal CSCs would be a promising chemo-preventive/ therapeutic strategy. Polymethoxyflavones including nobiletin (NBT) and 5-demethylatednobiletin (5DN) are exclusively found in citrus peels and have been shown to have anti-cancer effects. Our previous studies in the biotransformation and tissue distribution of NBT and 5DN have shown that in order to fuller evaluate the biological impact of those two …


Association Of Dietary Factors With Menstrual Cycle Characteristics, Radhika Natarajan Nov 2015

Association Of Dietary Factors With Menstrual Cycle Characteristics, Radhika Natarajan

Doctoral Dissertations

Abnormal menstrual cycle length, pattern and bleed duration are associated with reduced fecundity and increased risk of miscarriage. The menstrual cycle is governed by the hypothalamus-pituitary-ovarian (HPO) axis, and nutritional factors may affect menstrual characteristics by influencing the HPO axis. Identifying these factors may lead to cost effective ways to improve reproductive outcomes. In a cross-sectional analysis of 164 18- to 30-year-old women, we examined the association of adiposity, dietary fat intake and vitamin D status with menstrual cycle characteristics. Adiposity was measured using dual-energy X-ray absorptiometry (DXA); dietary intake was assessed using a food frequency questionnaire, and fasting venous …


Evaluation Of Spring Frost Control Methods And An Assessment Of Cold Hardiness In Cranberry (Vaccinium Macrocarporn Ait.), Faith Ndlovu Nov 2015

Evaluation Of Spring Frost Control Methods And An Assessment Of Cold Hardiness In Cranberry (Vaccinium Macrocarporn Ait.), Faith Ndlovu

Doctoral Dissertations

The American cranberry (Vaccinium macrocarpon Ait.) is an important temperate woody shrub crop whose fruit has human health benefits. Cranberry acquires cold hardiness in the autumn and loses it in spring, following deacclimation. Frost protection is necessary in cranberry production as a means to reduce bud damage due to low spring temperatures. The objectives of the field studies were to evaluate two methods of sprinkler irrigation for frost protection, the conventional approach consisting of continuous irrigation throughout the night (CON) and intermittent cycling of sprinklers (INT) incorporating cycling on and off throughout the night, by (i) assessing bud damage …


Utilizing In Silico And/Or Native Esi Approaches To Provide New Insights On Haptoglobin/Globin And Haptoglobin/Receptor Interactions, Ololade Fatunmbi Nov 2015

Utilizing In Silico And/Or Native Esi Approaches To Provide New Insights On Haptoglobin/Globin And Haptoglobin/Receptor Interactions, Ololade Fatunmbi

Doctoral Dissertations

Haptoglobin (Hp), an acute phase protein, binds free hemoglobin (Hb) dimers in one of the strongest non-covalent interactions known in biology. This interaction protects Hb from causing potentially severe oxidative damage and limiting nitric oxide bioavailability. Once Hb/Hp complexes are formed, they proceed to bind CD163, a cell surface receptor on macrophages leading to complex internalization and catabolism. Myoglobin, (Mb) a monomeric protein, that is normally found in the muscle but can be released into the blood in high concentrations during myocardial injury, is homologous to Hb and shares many conserved Hb/Hp interface residues. Both monomeric Hb and Mb species …


Fabrication, Characterization And Biological Fate Of Phytochemical Delivery System, Jingjing Chen Nov 2015

Fabrication, Characterization And Biological Fate Of Phytochemical Delivery System, Jingjing Chen

Doctoral Dissertations

Polymethoxyflvones (PMFs) are a group compounds with promising cancer preventing activities and many other health benefits. There's a growing interest in fabricating delivery systems for PMFs as well as other phytochemicals due to their low water solubility. Firstly, we use nanoemulsion delivery system to encapsulate β-carotene. Sonication assisted method was developed to dissolve β-carotene to ensure minimum degradation. Powdered nanoemulsion was obtained after spray dry and freeze dry. Sample obtained after freeze dry showed better physiochemical characteristics. Then we use protein nanoparticle delivery system to encapsulate PMFS. The nanoparticle delivery system was fabricated by mixing the aqueous phase …


Estimation Problems In Complex Field Studies With Deep Interactions: Time-To-Event And Local Regression Models For Environmental Effects On Vital Rates, Krzysztof M. Sakrejda Nov 2015

Estimation Problems In Complex Field Studies With Deep Interactions: Time-To-Event And Local Regression Models For Environmental Effects On Vital Rates, Krzysztof M. Sakrejda

Doctoral Dissertations

Field studies that measure vital rates in context over extended time periods are a cornerstone of our understanding of population processes. These studies inform us about the relationship between biological process and environmental noise in an irreplaceable way. These data sets bring ``big data'' and ``big model'' challenges, which limit the application of standard software (e.g., \textbf{BUGS}). The environmental sensitivity of vital rates is also expected to exhibit interactions and non-linearity, which typically result in difficult model selection questions in large data sets. Finally, long-term ecological data sets often contain complex temporal structure. In commonly applied discrete-time models complex temporal …


Behavioral, Neurobiological, And Genetic Analysis Of The Circadian Mutant Duper, Emily Nicole Corbett Manoogian Nov 2015

Behavioral, Neurobiological, And Genetic Analysis Of The Circadian Mutant Duper, Emily Nicole Corbett Manoogian

Doctoral Dissertations

The recently discovered circadian mutant hamster duper has a short period of ~23 hours and exhibits exaggerated phase shifts in response to a 15-min light pulse. To increase the understanding of the duper mutation, I performed behavioral, neurobiological, and genetic experiments. Behavioral studies using photic and non-photic stimuli found that large phase shifts exhibited by duper hamsters are specific to photic cues, but not to phase. Additionally, 2/3 of duper hamsters, but no WTs, displayed transient ultradian wheel-running patterns when transferred from light to dark at CT 18. This suggests that the mutation may weaken coupling among components of the …


How To Build A Spinal Cord: Exploring Radial Glial Proliferation And Their Contribution To Embryonic Neurogenesis, Kimberly A. Johnson Nov 2015

How To Build A Spinal Cord: Exploring Radial Glial Proliferation And Their Contribution To Embryonic Neurogenesis, Kimberly A. Johnson

Doctoral Dissertations

During embryonic neural development, the concerted actions of neural stem cells (NSCs) populate and pattern the tissues that will give rise to the brain and spinal cord. This heterogeneous NSC population initially consists of neuroepithelial cells, which will generate the first neurons present in the central nervous system (CNS) prior to transitioning into radial glial cells. Classically, radial glial cells are known to play a wide range of roles during CNS development, from maintaining neuronal homeostasis, as a scaffold for neuronal migration, and as a permissive growth substrate for directed axon pathfinding. Recently, radial glial cells have been proposed to …


Gestational Diabetes, Infant Feeding Practices, And Early Indicators Of Obesity Risk In A Sample Of Mother-Infant Dyads In The U.S., Kimberly N. Doughty Nov 2015

Gestational Diabetes, Infant Feeding Practices, And Early Indicators Of Obesity Risk In A Sample Of Mother-Infant Dyads In The U.S., Kimberly N. Doughty

Doctoral Dissertations

Research suggests that the trajectory to obesity and its associated metabolic disorders begins early in life. Prenatal exposure to maternal gestational diabetes mellitus (GDM) is associated with increased risk, while breastfeeding is associated with reduced risk. Breastfeeding may influence obesity risk by preventing rapid postnatal weight gain. Mothers with gestational diabetes may not breastfeed as intensely as healthy mothers, potentially exacerbating the risk to their infants. We conducted three distinct investigations related to gestational diabetes, breastfeeding, and infant weight gain. All used data from the U.S. Infant Feeding Practices Study II. Multivariate logistic regression was used to estimate associations between …


Cover Crop And Nitrogen Fertilizer Management For Potato Production In The Northeast, Emad Jahanzad Nov 2015

Cover Crop And Nitrogen Fertilizer Management For Potato Production In The Northeast, Emad Jahanzad

Doctoral Dissertations

Potato (Solanum tuberosum L.) rates fourth among the world’s agricultural products in terms of production volume and human consumption and worldwide demand for potatoes will exceed that of rice, wheat, or corn by 2020. Potato consumption has been a major part of the North American diet since early in the 17th century and as a dominant arable crop in the Northeastern United States. There are over 2700 potato fields in the Northeast United States and potato growers often over apply nitrogen (N) fertilizer to ensure against loss of yield. High mobility of nitrate form N fertilization in the …


An Integrative, Cost-Benefit Analysis On Animal Perturbations: Autotomy And Life-History Related Weight Gain, Chi-Yun Kuo Nov 2015

An Integrative, Cost-Benefit Analysis On Animal Perturbations: Autotomy And Life-History Related Weight Gain, Chi-Yun Kuo

Doctoral Dissertations

The variation in behavioral traits and the adaptive significance behind such variation has been a classic question in behavioral ecology. Traits that enhance while simultaneously impose high fitness costs are particularly suitable for addressing this fundamental question, as their expressions are likely under strong selection. In this dissertation, I investigate the variation in a costly antipredator behavior and the underlying cost-benefit mechanisms. The trait of interest is the voluntary shedding of the tail, or tail autotomy, in lizards. Tail autotomy allows lizards to survive close-range encounters with predators but also has severe fitness consequences, including increased energetic demand for regeneration …


Assessing Kiln-Produced Hardwood Biochar For Improving Soil Health In A Temperate Climate Agricultural Soil, Emily J. Cole Nov 2015

Assessing Kiln-Produced Hardwood Biochar For Improving Soil Health In A Temperate Climate Agricultural Soil, Emily J. Cole

Doctoral Dissertations

Soil quality has become a major factor used in assessing sustainable land management and the overall environmental quality, food security, and economic viability of agricultural lands. Recently, biochar has been touted as having many potential uses as a soil amendment for improving soil quality, specifically improving cation exchange capacity, pH and nutrient availability. However, soil biology also plays a significant role in biogeochemical processes that influence soil health and should be included in a more comprehensive study of soil health. This dissertation describes 4 projects within the same 3-year field study with the cumulative purpose of better understanding the effect …


Effects Of Overexpression Of Sap12 And Sap13 In Providing Tolerance To Multiple Abiotic Stresses In Plants, Parul R. Tomar Nov 2015

Effects Of Overexpression Of Sap12 And Sap13 In Providing Tolerance To Multiple Abiotic Stresses In Plants, Parul R. Tomar

Doctoral Dissertations

Environmental stresses are the one of the main reasons for the decline of crop production worldwide. In the past years, a major focus has been on improving plant species and their tolerance towards these stresses but not much has been achieved because of the limited knowledge of the gene/network of genes that might be involved in providing tolerance to such multiple abiotic stresses. Recently, members of Stress Associated Protein (SAP) family in plants have been shown to impart tolerance to multiple abiotic stresses. There are 14 SAP genes in Arabidopsis thaliana and these proteins contain A20, AN1 and C2H2 zinc …


Biophysical Characterization Of Katanin’S Regulation Of Microtubules, Megan E. Bailey Nov 2015

Biophysical Characterization Of Katanin’S Regulation Of Microtubules, Megan E. Bailey

Doctoral Dissertations

Microtubules, as an essential part of the cytoskeleton, require proper function as well as correct spatial and temporal localization. In order to achieve correct organization, microtubule-associated proteins (MAPs) regulate microtubule dynamics. Katanin, a known microtubule-severing enzyme from the AAA family of proteins, plays a role in regulating microtubules, but the mechanisms of microtubule control and the mechanism of severing activity remain to be elucidated. In the following studies I examine mechanisms of katanin-based regulation of microtubule dynamics using a single molecule biophysics approach. I use this simplified in vitro approach to change specific parameters to investigate how katanin targets microtubules …


Energetic Limitations Of Thermophilic Methanogens And Thiosulfate Reducers In The Subsurface Biosphere At Deep-Sea Hydrothermal Vents, Lucy C. Stewart Nov 2015

Energetic Limitations Of Thermophilic Methanogens And Thiosulfate Reducers In The Subsurface Biosphere At Deep-Sea Hydrothermal Vents, Lucy C. Stewart

Doctoral Dissertations

This dissertation examined the substrate and energetic limitations of hydrogenotrophic thermophiles from deep-sea hydrothermal vents. Thermophilic and hyperthermophilic organisms in diffuse hydrothermal venting are thought to represent a hot subsurface biosphere associated with deep-sea hydrothermal vents, where primary production is dominated by hydrogenotrophy rather than sulfide oxidation as at the vent/seawater interface of hydrothermal sulfide chimneys. Methanogens and sulfur-reducers are known to compete for hydrogen in mesophilic, freshwater systems, and likely do so in deep-sea hydrothermal vent environments as well. However, the exact size and biomass of the subsurface biosphere is difficult to determine through direct sampling. Firstly, the distribution …


Pro- And Antioxidant Effects Of Phospholipids On Lipid Oxidation In Bulk Oil, Leqi Cui Nov 2015

Pro- And Antioxidant Effects Of Phospholipids On Lipid Oxidation In Bulk Oil, Leqi Cui

Doctoral Dissertations

The aim of this thesis is to explore how phospholipids at concentrations similar as in refined vegetable oils impact bulk oil lipid oxidation. The possible formation of association colloids and synergism with primary antioxidants are considered. The results provided a better understanding of the pro- and antioxidant activities of phospholipids. Lipid oxidation leads to quality deterioration by generating off-flavor, nutrient loss, color alteration, texture changes, and even generation of potential toxic products. Phospholipids are important minor components in edible oil that play a role in lipid oxidation. Surface active phospholipids have an intermediate hydrophilic–lipophilic balance value, which allows them to …


Characterization Of The Role Of Intrinsic And Extrinsic Factors During Murine Endoderm Development, Siyeon Rhee Nov 2015

Characterization Of The Role Of Intrinsic And Extrinsic Factors During Murine Endoderm Development, Siyeon Rhee

Doctoral Dissertations

Yin Yang1 (YY1) is a ubiquitously expressed factor that plays multiple roles in early mouse development. We have found that an essential role of YY1 in the visceral endoderm (VE) of the yolk sac is the maintenance of VEGF. Furthermore, we have demonstrated that paracrine signals downstream of VEGF support the VE, assessed by maintenance of HNF4α. Because the VE is essential for yolk sac development, and thus for embryonic survival, we used an inducible-knockout strategy to demonstrate that YY1 is essential in the definitive endoderm (DE) for invasion of hepatoblasts into the surrounding mesenchyme. By E14.5 YY1-/- livers are …