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Full-Text Articles in Life Sciences
Examining Artifacts Of The Watershed Segmentation, Emily Jo Armitage
Examining Artifacts Of The Watershed Segmentation, Emily Jo Armitage
Electronic Theses and Dissertations
The watershed segmentation is an algorithm used to systematically track cell intercalary behaviors during germ band extension of the Drosophila embryo. Neighboring cells share a contracting vertical interface, called a T1, which continues contracting to a single point, a T2, and extending in the horizontal direction to create what is called a T3 interface (Fig. 1). Additionally, higher order vertices called rosettes occur when five or more cells meet at a common vertex. Simulated T2 events demonstrate that cell angle and not noise level in the image contributes to the incorrect detection of artifactual T1s in more acute angled cells …
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 …
Regulation Of Actin Dynamics During Drosophila Germband Extension, Ashley M. Motlong
Regulation Of Actin Dynamics During Drosophila Germband Extension, Ashley M. Motlong
Electronic Theses and Dissertations
Convergent extension is a process that occurs in the development of a wide variety of organisms, including gastrulation in the Drosophila embryo to begin to lay out the adult body plan. In fly embryos, this is known as germband extension and is mainly driven by cell intercalation or neighbor exchange by planar polarized cell-cell interface contraction to shorten the tissue along the dorsal-ventral axis. In this thesis, I show that interface contraction consists of phases of fast interface shortening and intervals of stable interface size. My data also suggests that regulation of F-actin aggregates at these shrinking interfaces is important …
Plasma Membrane Dynamics In The Drosophila Embryo, Amelia E. Zommer
Plasma Membrane Dynamics In The Drosophila Embryo, Amelia E. Zommer
Electronic Theses and Dissertations
Convergent extension is a highly conserved process among mammals, in which the tissue narrows in one axis, and extends across another. Tissue elongation is directed by the regulation of cell interface behaviors, which guides cell intercalation and rosette formation. Rosette formation occurs through the contraction of vertically oriented cell interfaces, and the subsequent elongation of new horizontal interfaces. It has been shown that actomyosin-generated tension functions to direct rosette formation. In this thesis, I have tested the function of regulators of F-actin networks, as well as endocytic and exocytic mechanisms, to identify new components that control interface behaviors and cell …