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Full-Text Articles in Life Sciences

Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren Jan 2020

Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren

Electronic Theses and Dissertations

Whereas a great deal has been learned about the molecular underpinnings of morphological evolution in animals, much less is known about the origin of novel cell and tissue types. During the time in which the earliest animal lineages were diversifying, fundamental cell and tissue types, such as muscles, arose. Sponges are one of two animal lineages that lack muscles, yet they undergo coordinated full body contractions. Whereas the signaling processes have been studied, the physical mechanisms of contraction are completely uncharacterized. The main purpose of this work is to understand the primary contractile tissue of the sponge Ephydatia muelleri, …


Quantification Of Mitochondrial Zinc Homeostasis And Analysis Of Zinc And Polyamine-Mediated Axonal Trafficking, Dylan Hunt Fudge Jan 2020

Quantification Of Mitochondrial Zinc Homeostasis And Analysis Of Zinc And Polyamine-Mediated Axonal Trafficking, Dylan Hunt Fudge

Electronic Theses and Dissertations

The zinc ion is an important emerging signaling molecule for biological processes. In this work we engineered improved zinc sensors based on our previously developed fluorescent sensor GZnP1 to provide sensors with a higher fluorescent readout, faster kinetics, and a superior sensitivity to zinc. We utilized these zinc sensors and further developed the sensors to answer questions pertaining to biological zinc. We showed the labile zinc concentration in the mitochondrial matrix was less than 1 pM while the labile zinc concentration in the cytosol and mitochondrial IMS were comparable (~100 pM) across four different cell lines. Using these zinc sensors …


Sorting Of Cargo Proteins Within The Regulated Secretory Pathway: The Peripheral Membrane Protein Hid-1 As A Sorting And Vesicle Biogenesis Factor, Blake H. Hummer Jan 2020

Sorting Of Cargo Proteins Within The Regulated Secretory Pathway: The Peripheral Membrane Protein Hid-1 As A Sorting And Vesicle Biogenesis Factor, Blake H. Hummer

Electronic Theses and Dissertations

Large dense core vesicles (LDCVs) form at the trans-Golgi network (TGN) and mediate the regulated release of neuropeptides and peptide hormones. Despite their central role to physiology, the mechanisms controlling biogenesis and sorting to LDCVs is not well understood. Optimizing the retention using selective hooks (RUSH) method in neuroendocrine cells, we show it is possible to visualize sorting to the constitutive and regulated secretory pathways in real-time and that the bulk of transmembrane LDCV cargoes do not sort directly onto LDCVs, but exit the TGN into non-regulated vesicles to be incorporated to LDCVs at a later step. Additionally, we characterize …


Quantification Of Dynamic Epithelial Sheet Architecture In Botryllus Schlosseri Using 2-D & 3-D Image Analysis, Roopa Madhu Jan 2020

Quantification Of Dynamic Epithelial Sheet Architecture In Botryllus Schlosseri Using 2-D & 3-D Image Analysis, Roopa Madhu

Electronic Theses and Dissertations

Epithelial tubules form critical structures in various body tissues; how- ever, since they are difficult to access experimentally, their architecture and dynamics are not well understood. Here we examine the dynamic remodeling of epithelial tubes in vivo using a novel and uniquely accessible model system: the extracorporeal vasculature of Botryllus schlosseri (sea squirt). In Botryllus, massive retraction of blood vessels can be triggered without loss of barrier function, through (i) disrupting collagen crosslinking in the basement membrane using β-aminopropionitrile (BAPN); or (ii) disrupting the integrin pathway through inhibition of focal adhesion kinase (FAK). We performed stereographic projections of 3-dimensional …


Cellular And Organismal Ramifications Of De Novo Purine Synthesis Dysregulation, Randall Craig Mazzarino Jan 2020

Cellular And Organismal Ramifications Of De Novo Purine Synthesis Dysregulation, Randall Craig Mazzarino

Electronic Theses and Dissertations

Purines are a class of nitrogenous bases and are essential small molecules to life. Purines are used within the cell as genetic information carriers, energy currency, signaling molecules, and cofactors for multiple processes. They are formed through de novo and salvage pathways found in cells across the phylogenetic tree. The substrates of enzymes within de novo purine synthesis are known to influence other processes within the cell, such as energy homeostasis. In humans, de novo purine synthesis disorders are rare, with around 100 people identified. These patients exhibit a range of phenotypes, with varying degrees of mental retardation, seizure activity, …


Ehbp1 And Ehd2 Regulate Dll4 Caveolin-Mediated Endocytosis During Blood Vessel Development, Amelia Margaret Webb Jan 2020

Ehbp1 And Ehd2 Regulate Dll4 Caveolin-Mediated Endocytosis During Blood Vessel Development, Amelia Margaret Webb

Electronic Theses and Dissertations

During angiogenesis, the development of new blood vessels from existing vessels, there must be tight regulation between a leading tip cell and trailing stalk cells during vascular patterning. Lateral inhibition produced by Notch signaling is central to the specification and maintenance of tip and stalk cells in growing angiogenic sprouts. The Notch pathway is activated by the ligand Delta at adherens junctions between tip and stalk cells. Despite the centrality of Delta/Notch signaling to angiogenesis, relatively little is known about the mechanism of this signaling event. It has been proposed that the force generated by the Notch bound Delta ligand …


Actin Regulation And Furrow Dynamics During Early Drosophila Embryogenesis, Yi Xie Jan 2020

Actin Regulation And Furrow Dynamics During Early Drosophila Embryogenesis, Yi Xie

Electronic Theses and Dissertations

Drosophila embryogenesis starts with a single nucleus undergo 13 rounds of nuclear divisions called syncytial cycles. Staring at cycle 10 when nuclei migrate to the surface of the embryo, massive and dynamic cortical actin structures and cleavage furrow formations occur. How actin regulators coordinate into an organized network directing three-dimension actin structures in the developing organisms is an unsolved question. Here, I present an in-depth characterization of actin cap dynamics: the actin caps go through expansion, stabilization, elongation and fragmentation phases in each cycle. Arp2/3 is the major contributor to actin cap formation. The functions of 7 different actin and …