Biology Commons^™

Marine Population Connectivity: Range Boundaries And Climate Change, Rhiannon Leigh Rognstad

Theses and Dissertations

Population connectivity, particularly in open systems, is an important metric for understanding population-level processes on both ecological and evolutionary timescales. In coastal marine systems, adults are typically sedentary and dispersal occurs primarily during a larval stage when individuals are transported in ocean currents. Because coastal marine populations exist as networks of interconnected subpopulations, variation in the magnitude and extent of population connectivity can have profound effects on population dynamics and species distribution limits. Connectivity is a complex process, affected by a multitude of factors, including adult inputs and physical dispersal, which operate at multiple scales and may interact. This dissertation …

Ferric Reductases And Transporters That Contribute To Mitochondrial Iron Homeostasis, Anshika Jain

Theses and Dissertations

Iron (Fe) is the fourth most abundant element in the Earth’s crust, yet the availability of Fe to plants is often limited. This is because in most soil types, Fe precipitates as ferric-oxyhydroxy complexes, making it unavailable for uptake by plants. While the mechanisms involved in Fe uptake from the soil are relatively well understood, the mechanisms involved in its further distribution to the aerial portion of the plant and to subcellular compartments are not fully understood. During Fe deprivation, plants up-regulate root Fe acquisition machinery. How plants sense Fe deprivation and tie the Fe status of the plant to …

Molecular Mechanisms Of Gap Junction Regulation By The E3 Ubiquitin Ligase Wwp1, Measho Hagos Abreha

Theses and Dissertations

Ubiquitylation is a post-translational modification that influences a wide variety of cellular processes including protein degradation, protein subcellular localization, cell cycle progression, transcription, and DNA damage repair. Covalent attachment of the small ubiquitin molecule to a target protein involves the sequential action of three enzymes (E1, E2, and E3). In this process, substrate specificity is conferred by the E3 ligase. Our work has focused on the function of one such E3 ubiquitin ligase, WWP1. Known targets of WWP1 include cell cycle proteins, tumor suppressors, and transcription factors that promote differentiation of mesenchymal stem cells to the osteoid lineage. Recently, we …

The Role Of Lis1 In Adult Mammalian System, Xu Gao

Theses and Dissertations

Lis1 haploinsufficiency in humans results in a “smooth brain” phenotype called lissencephaly, and also causes severe cognitive and motor impairments and epilepsy. Seizure severity and frequency typically worsens with time; patients often die within the first decade due to seizure-induced aspiration and pneumonia. Various mouse models have been used to examine the role of Lis1 during brain development, and it is clear that Lis1 regulates a microtubule motor, cytoplasmic dynein. Intriguingly, Lis1 expression remains high in adult brains indicating that it plays a role in mature systems. Indeed, our group found that Lis1 and several related proteins regulate dynein-dependent axon …

Understanding The Evolutionary History Of Biochemical Innovation, Madeline Opal St. Julien

Theses and Dissertations

The serine protease (SP) gene family is an ecologically important gene family because of observed involvement in innate immunity, digestive processes, and embryological development of arthropods. In the past decade, all genes of the serine protease family have been classified in a number of arthropods, with the exception of crustacean. Possible evolutionary mechanisms have been observed based off of varying selectional pressures acting on recent SP expansions in respect to varying diets. Daphnia is the first crustacean to have its genome sequenced, and their genomes were analyzed in this study to elucidate the expansion and divergence of the SP gene …

Diversity, Genetics, And Health Benefits Of Sorghum Grain, Davina Rhodes

Theses and Dissertations

Staple cereal crops provide the majority of nutrients to the world's population, and thus, can significantly impact human nutrition and health. Phenotypic and genetic diversity within a crop can be useful for biofortification and crop improvement, but quantitative phenotyping is needed to identify varieties with high or low concentrations of a nutrient of interest, and to identify alleles responsible for quantitative trait variation of the nutrient. Sorghum [Sorghum bicolor (L.) Moench] is a diverse and widely adapted cereal crop that provides food for more than 500 million people in sub-Saharan Africa and Asia, and is becoming increasingly popular in specialty …

Thermal Ecology And Physiology Of An Intertidal Predator-Prey System: Pisaster Ochraceus And Mytilus Californianus, Cristian J. Monaco

Theses and Dissertations

Untangling natural systems’ complexity requires understanding the mechanisms responsible for organisms’ responses to environmental change. Recently, significant advances have been made by recognizing the relevance of direct and indirect effects, which take place when multiple biotic and abiotic factors influence each other. I examined potential direct effects of environmental variables on a predator-prey interaction, as well as potential indirect effects of these variables on the interaction itself. I placed emphasis on behavioral and physiological adaptations, which would potentially contribute/modify these effects. My study system was comprised of a rocky intertidal keystone predator, the sea star Pisaster ochraceus, and its main …

Compositional Traits In Sorghum Bicolor Characterized By Transcriptome, Ionome And Genome-Wide Association Analysis, Nadia Shakoor

Theses and Dissertations

To address the challenge of global mineral malnutrition, current biofortification research in crop plants aims to improve mineral concentration and micronutrient bioavailablity via genetic and traditional breeding methods. Many staple food crops are also used as biofuels, and the chemical and mineral composition of these energy crops directly affect biomass quality and subsequent energy output. Identification of genes and QTL that impact mineral and compositional traits in the grain and biomass of major cereals, including sorghum, is fundamental to developing breeding and selection methods aimed at increasing bioavailable minerals and improving biofuel suitability and seed nutritional quality. A combinatorial strategy …

The Roles Of Gsk-3ss And Apc In Cytoplasmic Dynein Regulation, Feng Gao

Theses and Dissertations

Dynein is a microtubule minus-end directed molecular motor, participating in a broad range of cellular functions, such as organelle transport, cell migration and mitosis. Dynein dysfunction is linked to many diseases including ALS, schizophrenia, Alzheimer’s disease, Parkinson’s disease and cancer. The mechanism of dynein regulation is largely unknown. We have provided evidence that glycogen synthase kinase 3β (GSK-3β) directly regulates dynein in both neurons and non-neuronal cells. GSK-3β interacts with and phosphorylates dynein in vitro. Dynein phosphorylation by GSK-3β reduces its interaction with Ndel1, a regulator contributing to dynein force generation. Dynein motility is stimulated both by pharmacological GSK-3β inhibitors …

Global Climate Change And The Southern Ocean: How Antarctic Fishes Physiologically Respond To A Changing Environment From The Cellular To The Organismal Level, Laura A. Enzor

Theses and Dissertations

Studies have projected that future changes in sea surface temperature and pCO2 levels will impact higher latitudes to a greater extent than in temperate regions. For notothenioid fishes of the Southern Ocean, evolution in extremely stable, cold waters has resulted in several adaptations which have left these fishes poorly prepared for global climate change. I have analyzed the metabolic and cellular response of Trematomus bernacchii, Pagothenia borchgrevinki and Trematomus newnesi to a long-term, multi-stressor scenario relevant to the predicted changes in the Southern Ocean. By combining whole animal respirometry with cellular level analysis of energy allocation, osmoregulatory mechanisms and cellular …

Muscarinic Modulation Of Basolateral Amygdala, Lei Liu

Theses and Dissertations

The basolateral amygdala (BL) receives a dense cholinergic innervation from the basal forebrain. Despite the importance of muscarinic acetylcholine receptors (mAChRs) in fear learning, consolidation, and extinction, there have been no studies that have systematically investigated the functional role of mAChRs in regulating emotional processing in the BL. To address this critical knowledge gap we combined brain slice whole-cell recording, optogenetics, and immunohistochemistry to determine how muscarine, acting on mAChRs, regulates neuronal oscillations, synaptic transmission and plasticity in the BL.

Neurons in the BL oscillate rhythmically during emotional processing, which are thought to be important to integrate sensory inputs, allow …

Differential Expression Of Snmps And Their Underlying Transcriptional Regulation In Chemosensory Pathways Of Drosophila, Richard A. Fandino

Theses and Dissertations

Insects possess complex and diverse chemosensory pathways which have specific phenotypes determined by the regulated expression of specific combinations of genes. While many of these genes (e.g. ORs and GRs) have very narrow expression patterns, associating with only a limited number of chemosensory sensilla, SNMPs show a very broad expression pattern. In Drosophila, SNMP1 and SNMP2 associate with the majority of olfactory and gustatory sensilla, but express in different cell types. In olfactory sensilla, SNMP1 and SNMP2 associate with trichoid or coeloconic neurons respectively, and both additionally express in a variety of sensilla support cells; in gustatory sensilla, SNMP2 expresses …

Functional Characterization Of Fro4 And Fro5: Two Members Of The Ferric Chelate Reductase Family Of Arabidopsis, Grandon Thomas Wilson

Theses and Dissertations

Iron (Fe) is the fourth most abundant element within the earth’s crust and is an essential micronutrient for plants and animals. Fe plays key roles in photosynthesis, respiration and chlorophyll biosynthesis in plants and in hemoglobin in animals. Like Fe, copper (Cu) is also an important micronutrient in plants and is needed for photosynthesis and respiration, especially in the important copper-containing protein plastocyanin. Copper also is important in scavenging reactive oxygen species and ethylene perception. The reduction of Fe3+ to Fe2+ at the root surface of Arabidopsis thaliana during times of Fe deficiency has been a well-characterized process; however, reduction …

An Investigation Of Mitochondrial Bioenergetics And The Turnover Of Succinated Proteins In The Adipocyte During Diabetes, Ross Tanis

Theses and Dissertations

We previously identified the chemical modification S-(2-succino)cysteine (2SC), which is formed when the Krebs cycle metabolite fumarate reacts with protein cysteine residues, also termed protein succination. Protein succination is increased in the adipose tissue of ob/ob and db/db mice in vivo and in 3T3-L1 adipocytes grown in high glucose in vitro. The increase in 2SC in the 3T3-L1 adipocyte occurs as a direct result of glucotoxicity and increased mitochondrial stress. We have shown that uncoupling agents, which lower mitochondrial stress, prevent the increase in succinated proteins.

In this study we examined the relationship between increased succination and mitochondrial bioenergetics in …

Role Of Apelin And Endothelin Systems In The Pain Associated With Sickle Cell Disease, Terika Smith

Theses and Dissertations

Sickle cell disease (SCD) is a common genetic blood disorders that is characterized by painful vaso-occlusive episodes (VOEs), which are the major cause of hospitalizations for these patients. One of the mechanisms that may contribute to the development of painful VOEs is the imbalance between vasoconstrictors and vasodilators. This thesis focuses on the vasoconstrictors endothelin-1 (ET-1), which is elevated during VOEs and is pro-nociceptive, and angiotensin II (Ang II) and the vasodilator apelin, which has anti-nociceptive properties. This thesis tested two hypotheses: 1) an imbalance between the vasoconstrictive and pro-nociceptive systems and vasodilatory and anti-nociceptive systems contributes to pain in …

Mechanical Properties Of Diet And Its Effect On Oral Health, Varsha Kapoor

Theses and Dissertations

The predominant diet fed to captive carnivores consists of ground meat formulated to provide full nutritional requirements. However, this ground meat diet completely lacks the mechanical properties such as toughness, hardness and stiffness of the foods the animals would eat in the wild. The goal of this research was to evaluate the effect of mechanical properties of diet on oral health by comparing prevalence of periodontal disease and calculus accumulation in wild and captive felids. One-way ANOVA analysis of variance indicated that these differences are statistically significant (P

Genetic Background Influences Behavior And Responses To Epigenetic Changes Induced By A Methyl-Donor Diet, Kimberly R. Shorter

Theses and Dissertations

With recent strides in epigenetics, mainstream media informs the public that we can “beat our genes” by, for instance, changing our diet. Genetics, however, still plays a role in phenotype. Folate and other methyl-donor pathway components are widely supplemented due to their ability to prevent neural tube defects during prenatal development. In addition to vitamins, these compounds are also added to commercial flour, energy drinks, and other supplements. Several lines of evidence suggest that these supplements act through epigenetic mechanisms, including altering DNA methylation. Increasing evidence suggests potential deleterious effects of excessive folate. Given the benefits of these compounds, risk …

Utilizing Next Generation Sequencing To Generate Bacterial Genomic Sequences For Evolutionary Analysis, Derrick C. Scott

Theses and Dissertations

Many important questions in the field of prokaryotic biology cannot be answered due to the low availability of sequenced and finished genomes. Recent improvements in technology and decreases in price have made the ambition of de novo bacterial genomic sequencing a reality for a wide range of researchers. However, with the advancement of sequencing technology comes the need for an evaluation to determine the most reliable bioinformatics methods in generating a complete and accurate assembly. Biases inherent in the sequencing technology and GC-rich genomes complicate genome assemblies. Here, we sequenced bacterial strains from the GC-rich Caulobacter genus and the closely …

Genome Sequence And Phenotypic Characterization Of Caulobacter Segnis, Sagar Patel

Senior Theses

Caulobacter segnis is a unique species of Caulobacter in that it is slow growing, found in soil samples, and has other phenotypic differences from the freshwater Caulobacter that it is most closely related to. Initially deemed Mycoplana segnis, it was reclassified after a 16s rRNA analysis and found to be most closely related to the Caulobacter NA1000 branch. Because the annotated sequence available in GenBank contained a large number of pseudogenes (126), we compared the original sequencing data to the GenBank sequence and determined that many of the pseudogenes were due to sequence errors in the Genbank sequence. Consequently, …

Determining A Correlation Between Individual Differences In Eye Movements And Working Memory, Mackenzie Sunday

Senior Theses

This study determined if a relationship exists between individual differences in eye movements and working memory measures. The eye movement system can provide insight into processes that occur in the mind as well as a better understanding of the relationship between quantifiable aspects of eye movements and the more abstract inner workings of the mind. Recently, consistent and reliable individual differences have been found in individuals’ eye movement behaviors. For example, individuals with longer fixation durations for one visual task have longer fixations across all other visual tasks. The eye movements of participants were collected during four different viewing tasks …

The Role Of Lipocalin 2 In Early Stage Colon Cancer Metastasis To The Liver, Fides Elamparo

Senior Theses

Metastasis, frequently from the colon to the liver, is the major cause of death with colorectal cancer, reducing the five-year survival to less than 6%. Metastasis occurs due to productive collaborations between tumor cells and host-derived cells in the tumor microenvironment, where a pre-metastatic niche is created to prime for cancer cell invasion into the target organ. In a highly metastatic colorectal cancer cell line implanted into the cecum of Balb/c mice, microarray analysis showed lipocalin 2 (Lcn2) is one of the most highly expressed proteins in the liver of tumor-bearing mice prior to metastasis.

When RT-PCR was performed, greater …

Identification Of Microrna Biomarkers In Her2-Positive Breast Cancer, Hossam Tashkandi

Theses and Dissertations

Human epidermal growth factor receptor 2 (HER2) is overexpressed in approximately 30% of breast cancer patients with poor prognosis. In addition, microRNAs are small non-coding RNA that have been linked to many cancers. Here we investigate which miRNAs are differentially regulated by HER2 overexpression. Using quantitative reverse-transcription prolymerase chain reaction (QRT-PCR) and matching it with the clinical data acquired from Dvinge, we find five candidate miRNAs. When comparing the miRNAs’ effect on patient survival, only three miRNAs stand as good predictors of patient survival outcome. These miRNAs are miR-146a-5p, miR-181d, and miR-195-5p. When miR-146a-5p is up-regulated, which is the case …