Cell Biology Commons^™

Recovery From Social Isolation In Drosophila: The Role Of Dopamine And The Autism-Related Gene Nlg3., Ryley T. Yost

Electronic Thesis and Dissertation Repository

Within a group, individuals establish their preferred distance from each other, or social space, a form of social behaviour. The resulting distance depends on the exchange of social cues from others that needs to be perceived and integrated within the organism’s neural circuitry. In humans, social spacing can be impaired in neuropsychiatric disorders such as autism and schizophrenia. When organisms are subject to social isolation, profound changes in social behaviour are observed in a variety of species from insects to mammals, including social space. However, the genetic and molecular mechanisms modulating a behavioural response to isolation and possible recovery remain …

Characterization Of Mechanotransduction In Annulus Fibrosus Cells, Min Kyu M. Kim

Electronic Thesis and Dissertation Repository

IVD degeneration is a multifactorial pathological process associated with back pain. While biomechanical factors are important regulators of IVD homeostasis, mechanical loading also contribute to the onset of IVD degeneration. Importantly, the mechanotransduction pathways that mediate cell type-specific responses to mechanical loading are not well understood. Transient receptor potential vanilloid 4 (TRPV4) is a multimodally activated cell surface cation channel implicated as a mechanoreceptor regulating the mechano-response in other musculoskeletal cell types. Using both in vitro and in vivo models, the current study aimed to characterize the role of TRPV4 in annulus fibrosus (AF) cell mechanotransduction. Using a mechanically dynamic …

Regulators Of Ectopic Calcification In A Mouse Model Of Dish: A Multi-Omics Perspective, Matthew A. Veras

Electronic Thesis and Dissertation Repository

Diffuse idiopathic skeletal hyperostosis (DISH) is a non-inflammatory spondyloarthropathy and the second most common form of arthritis characterized by formation of ectopic mineral along the spine. Pathological findings in DISH include regional calcification of the anterior longitudinal ligament, paraspinal connective tissues, and annulus fibrosus (AF) of the intervertebral disc (IVD). Clinical symptoms of DISH include increased spine stiffness, decreased spinal range of motion, and in severe cases dysphagia and spinal cord/nerve root compression. The molecular pathways responsible for DISH have not been delineated and as such, there are no disease-modifying treatments. Clinical treatment for DISH is limited to surgical resection …

Thyroxine-Dependent And -Independent Effects On Premature Aging And Myelination In Atrx Mutant Mice, Megan E. Rowland

Electronic Thesis and Dissertation Repository

ATRX is an ATP-dependent chromatin remodeler required to safeguard genomic integrity. Conditional deletion of Atrx in the mouse embryonic forebrain and anterior pituitary in Atrx^Foxg1Cre mice phenocopies mouse models of progeria which display increased DNA damage, coupled with reduced lifespan, growth and subcutaneous fat. These mice also have severely low circulating levels of insulin like growth factor 1 (IGF-1) and (T4) which have been reported in models of premature aging. Based on evidence that Igf1 is activated by the ligand-bound thyroid hormone receptor, I tested whether T4 supplementation could restore IGF-1 levels and ameliorate premature aging phenotypes in Atrx …

Characterization Of Plant-Spider Mite Interactions And Establishment Of Tools For Spider Mite Functional Genetic Studies, Nicolas Bensoussan

Electronic Thesis and Dissertation Repository

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most polyphagous herbivores feeding on cell contents of over 1100 plant species including more than 150 crops. However, despite its important pest status and a growing understanding of the molecular basis of its interactions with plant hosts, knowledge of the way mites interface with the plant while feeding and the plant damage directly inflicted by mites is lacking. Likewise, while the use of the reverse genetic tools in plants facilitated our understanding of the establishment of defense mechanisms against spider mite herbivory, such tools are lacking for …

Characterization Of Acaricide Resistance, Plant-Mediated Rnai Against Two-Spotted Spider Mites (Tetranychus Urticae Koch), And Assessing Off- And Non-Target Effects, Hooman Hosseinzadeh Namin

Electronic Thesis and Dissertation Repository

The two-spotted spider mite (TSSM), Tetranychus urticae (Koch), is one of the most damaging agricultural pests in the world. It feeds on over 150 crops, causing considerable yield losses in greenhouses and agricultural fields. Currently, using synthetic acaricides is the main method to control TSSM. However, it can develop resistance to acaricides with repeated exposure, and typically resistance can occur within two to four years. To understand the underlying mechanisms of spider mite adaptation to acaricides is an essential part of resistance management strategy. The resistance ratio of the pyridaben-selected strain compared with the pre-selection strain was estimated at greater …

The Effect Of Diet On Midgut And Resulting Changes In Infectiousness Of Acmnpv Baculovirus In Trichoplusia Ni, Elizabeth Chen

Electronic Thesis and Dissertation Repository

The cabbage looper, Trichoplusia ni, a global generalist lepidopteran pest, has developed resistance to many synthetic and biological insecticides, requiring effective and environmentally acceptable alternatives. One possibility is the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). This baculovirus is highly infectious for T. ni, with potential as a biocontrol agent, however, its effectiveness is strongly influenced by dietary context. In this study, microscopy and transcriptomics were used to examine how the efficacy of this virus was affected when T. ni larvae were raised on different diets. Larvae raised on potato host plants had lower chitinase and chitin deacetylase transcript levels …

Cellular/Molecular Analysis Of Interspecies Sterile Male Hybrids In Drosophila, Rachelle L. Kanippayoor

Electronic Thesis and Dissertation Repository

Over time, genetic differences can accumulate between populations that are geographically separated. This genetic divergence can lead to the evolution of reproductive isolating mechanisms that reduce gene flow between the populations and, upon secondary contact, result in distinct species. The process of speciation is, thus, what accounts for the multitude of species that contribute to the rich biodiversity on Earth. Interspecies hybrid sterility is a postzygotic isolating mechanism that affects the development of hybrids, rendering them sterile. A notable trend, known as Haldane's Rule, describes that heterogametic individual (e.g. males in Drosophila) are more susceptible to sterility than homogametic …

Nucleoporin-Mediated Regulation Of The Kcnq1ot1 Imprinted Domain, Saqib Sachani

Electronic Thesis and Dissertation Repository

Genomic imprinting is an epigenetic phenomenon that restricts gene expression to one parental allele while the other copy is silent. How this duality is regulated is not fully understood. Using the Kcnq1ot1 imprinted domain as a model, previous work in the laboratory identified nucleoporin 107 as a candidate regulator of imprinted domain regulation. Within the Kcnq1ot1 domain resides the imprinting control region, the paternally expressed Kcnq1ot1 (Kcnq1 opposite transcript 1) noncoding RNA, nine maternal-expressed protein-coding genes, as well as genes that escape imprint regulation. On the maternal allele, the Kcnq1ot1 imprinting control region is methylated, silencing the embedded Kcnq1ot1 …

Hd2d Is A Regulator Of Abscisic Acid Responses In Arabidopsis, Joshua A. Farhi

Electronic Thesis and Dissertation Repository

Histone deacetylases have important roles in development and stress response in plants. To further investigate their function, the HD2D gene, of the plant specific HD2 family, was studied. An hd2d-1 mutant and two HD2D overexpression lines were used in this study. Germination was delayed in hd2d-1 and HD2D overexpression seeds only in the presence of ABA. HD2D was found to positively regulate the expression of members of the ABA-response pathway (ABI1, ABI5, and RD29A) leading to increased resistance to drought and salinity treatments. Furthermore, HD2D expression delayed flowering by positively regulating FLC expression. Using bimolecular fluorescence complementation, the HD2D protein …

Soybean Isoflavonoid Biosynthesis: Constituents And Circumstance At The Transcriptomic And Molecular Levels, Mehran Dastmalchi

Electronic Thesis and Dissertation Repository

Isoflavonoids are specialized metabolites, almost exclusive to the legume family of plants. They are actors in symbiosis with nitrogen-fixing bacteria and in plant stress response. Isoflavonoids are noted for their human health benefits. Isoflavonoid content in legumes has proven to be a complex trait. The goal of the present research is to determine the mechanisms underlying isoflavonoid biosynthesis in soybean.

The first approach was to unravel the genetic factors of isoflavonoid biosynthesis. A branch-point enzyme of the phenylpropanoid pathway, chalcone isomerase (CHI), catalyzes the reaction producing flavanones, the nucleus for many downstream metabolites such as isoflavonoids. I identified twelve soybean …

Editorial Overview: Environmental Physiology: Insect Environmental Physiology, Brent J. Sinclair

Biology Publications

No abstract provided.

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 …