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Full-Text Articles in Life Sciences
Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren
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
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
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
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
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
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
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 …
Rab8 Directs Tubulation And Furrow Ingression During Epithelial Formation In Drosophila Melanogaster, Lauren Mackenzie Mavor
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 …
Rala And Rab8 Regulate Drosophila Embryogenesis, Zhongyuan Zuo
Rala And Rab8 Regulate Drosophila Embryogenesis, Zhongyuan Zuo
Electronic Theses and Dissertations
Pseudocleavage furrow dynamics initiate at cycle 10 to help with mitotic divisions that lack cytokinesis. Permanent furrows then form at the beginning of cellularization (cycle 14). Cytoskeletal networks such as F-actin and non-muscle Myosin II have been demonstrated to be required for furrow formation and provide anchor points for chromosomal segregation. However, what drives the onset of furrow formation and membrane addition remains largely unclear. In my thesis, I have explored RalA and Rab8 function during furrow formation at metaphase and cellularization stages. These furrows are critical for correct chromosomal segregation, while disruption of furrow formation results in severe developmental …
Neuronal Calcium Regulation And Cellular Stress In A Malignant Hyperthermia Disease Model, Jason Santiago
Neuronal Calcium Regulation And Cellular Stress In A Malignant Hyperthermia Disease Model, Jason Santiago
Electronic Theses and Dissertations
Calcium ions (Ca2+) are essential signaling molecules and must be carefully regulated to preserve specificity in function. One indispensible Ca2+ signaling protein is the ryanodine receptor (RyR) calcium release channel. RyR1 is essential for muscle contraction, and RyR1mutations can lead to severe muscle disorders such as malignant hyperthermia (MH). Recently, a mouse model of human MH (Y522S-RyR1) has been developed. In skeletal muscle, Y522S-RyR1 exhibits an increased sensitivity to activation resulting in Ca2+ leak, mitochondrial disorganization, and cellular stress. Although RyR1 expression is limited in the brain, the cerebellum may be particularly vulnerable to this disease because RyR1 is highly …
Purinergic Receptors In The Circumvallate Papillae Of Rats, Alana Marselle Montoya
Purinergic Receptors In The Circumvallate Papillae Of Rats, Alana Marselle Montoya
Electronic Theses and Dissertations
P2X2 receptors and P2Y4 receptors are ATP-activated cell surface receptors that gate movement of K+, Na+, and Ca2+. We used immunocytochemistry for P2X2 and P2Y4 receptors as well as taste cell type markers to learn if P2X2 immunoreactivity (IR) is present in nerve processes in close apposition to Type II and/or Type III taste cells. We also tested to see if P2Y4 IR is present in Type II and/or Type III taste cells. Our results indicate that P2X2 is present only in intragemmal nerve processes. P2X2-LIR nerve processes form close contacts with Type II and Type III taste cells. P2Y4 …