Life Sciences Commons^™

Thinking Beyond The Fried Egg Model: How Accurately Do Students Perceive Cells In A Living Context?, Milissa Knox

Electronic Theses and Dissertations

This exploratory study investigated three aspects of introductory undergraduate biology students’ understanding about cells. The study, which took place at the University of Maine with voluntary students in Basic Biology (“BIO100”) in the summer and fall of 2009, examined (1) students’ pre-course perceptions of cells as they exist in a living context and (2) gains in students’ perception and knowledge about cells after completing the one-semester course (BIO100). Results are based on lecture exam scores, pre-post surveys developed as a part of this thesis, and interviews with two groups of biology students. A total of 498 students participated in the …

Regulation Of The Retinoblastoma Tumor Suppressor By The Novel Ras Effector Nore1a., Thibaut François Barnoud

Electronic Theses and Dissertations

Ras is the most frequently mutated oncogene in human cancers. It acts as a critical branch point in signal transduction, regulating numerous downstream effectors involved in cell growth and differentiation. While Ras can activate many growth promoting pathways, it can paradoxically regulate growth inhibitory pathways leading to apoptosis and cell cycle arrest. One of the ways Ras can inhibit the growth of cells is via a family of effectors called the RASSF proteins. RASSF5 (NORE1A) is a tumor suppressor that is frequently inactivated in human tumors by epigenetic mechanisms. NORE1A binds directly to Ras and promotes Ras-induced senescence. We have …

The Ras Effector Nore1a Forms A Tumor Suppressor Complex With Brca1., Nicholas C Nelson

Electronic Theses and Dissertations

Ras proteins function as molecular signaling switches that can stimulate multiple mitogenic pathways in response to extracellular signaling. Oncogenic activation of Ras by structural mutation is a highly transforming event in ~1/3 of human cancers. However, aberrant Ras activation can also promote oncogene-induced senescence. This Ras-induced irreversible growth arrest is a physiological process that acts as a barrier to malignancy. The mechanisms by which Ras drives senescence and how this process is bypassed during Ras-driven transformation remains poorly understood.

Although mutations in the RAS gene are extremely rare in human breast cancer, the Ras signaling pathway is constitutively activated in …

Microengineering The Neural Tube, Christopher Demers

Electronic Theses and Dissertations

Early embryonic development is a complex and highly regulated orchestra of instructive cues that collectively guide naïve stem cells towards progressively more specialized fates. In the neural tube, the precursor structure to the brain and spinal cord, these signals emanate from ‘organizing centers’ surrounding the neural tube. These organizing centers send out soluble cues or morphogens that diffuse tens to hundreds of microns to recipient cells residing in the neural tube. Re-creating this dynamic landscape of cues in vitro is impossible using standard cell culture tools and techniques. However, microfluidics is perfectly suited to fill this gap, allowing precise control …

Rab8 Directs Tubulation And Furrow Ingression During Epithelial Formation In Drosophila Melanogaster, Lauren Mackenzie Mavor

Electronic Theses and Dissertations

One of the most fundamental changes in cell morphology is the formation of a plasma membrane furrow. The Drosophila embryo undergoes several cycles of rapid furrow ingression during early development, which culminates in the formation of an epithelial sheet. Previous studies have demonstrated the requirement for intracellular trafficking pathways in furrow ingression; however, the pathways that link compartmental behaviors with cortical furrow ingression events have remained unclear. This research shows that Rab8, a small GTPase associated with late exocytic trafficking events, demonstrates striking dynamic behaviors in vivo; transitioning from punctate structures to a stable association with the cortex during …

Regulation Of Synaptogenesis By The Mirna Pathway And Fmr/P Bodies, Jacqueline Rochelle Furlong

Electronic Theses and Dissertations

Post-transcriptional regulation of mRNA is facilitated by different mechanisms, such as microRNA (miRNA) induced gene silencing or fragile X mental retardation protein (FMRP) mediated repression either independent of or acting through cytoplasmic RNA Processing bodies (P bodies). DPTP99A, Lar, and Wg have known functions during synaptogenesis and may be targets of miR-8. Here, we provide evidence that miR-8 regulates DPTP99A in vitro. Non-endogenous miR-8 expressed using an UAS driver regulates Lar. Endogenous miR-8 may regulate DPTP99A in vivo. Here we show that FMRP is capable of colocalizing with the P body components: DCP1, HPat, and Me31B, but not …

Myosin 10 Is Required For Spinal Motor Axon Growth And Guidance In Zebrafish Embryos, Crystal Ivey

Electronic Theses and Dissertations

Neurodevelopmental disorders are disabilities caused by malfunctioning mechanisms within the developing nervous tissue. These abnormalities often result in conditions such as autism spectrum disorders, Attention Deficient Hyperactivity Disorder (ADHD), motor dysfunctions, learning disabilities and mental retardation. Recent surveys indicate that there will be a 12% increase of children in the United States alone who are affected by neurodevelopmental disorders. Thus, it is important to understand both the normal and abnormal mechanisms of neural development. Neural development involves specification of new neurons and formation of neural circuits that connect the nervous system to every organ of the developing embryo. Neural circuits …

Myosinx Is Required For Craniofacial Development In Danio Rerio, Cole Yancey

Electronic Theses and Dissertations

Craniofacial development is the process of laying early cartilage and bone patterns in the anterior region of the embryo, which ultimately results in shaping the structure of the face and head of an organism. Craniofacial abnormalities in humans, such as cleft lip and palate, are among the most common of all birth defects. Therefore, investigating the molecular mechanisms involved in craniofacial development will help us understand both evolutionary processes and genetic diseases. Craniofacial cartilage and bone structures are almost entirely derived from neural crest cells. Neural crest are a pluripotent migratory stream of cells that originate from the early developing …