Molecular Biology Commons^™

Quantum Dots' Toxicity: A Multi-Level Investigation On The Impact Of Quantum Dots On The Actin Cytoskeleton, Nhi Le

MSU Graduate Theses

Quantum dots (QDs) are fluorescence nanomaterials with unique optical and physical properties. As such, they are highly sought after for their potential use in several biomedical and industrial applications. Despite their vast potential, recent studies have suggested that quantum dots are toxic to cells. Yet, the mechanism of quantum dots’ toxicity remains unclear. As such, my thesis aims to comprehensively examine the mechanism of quantum dots’ toxicity, emphasizing how quantum dots disrupt the actin cytoskeleton. In this study, I used RNA sequencing and mass spectrometry to investigate the influence of CdSe/ZnS QDs on the transcriptomic proteomic level of Saccharomyces cerevisiae …

Novel Mechanistic Insight Into Ciliary Regulation: Old Pathways Yield New Mechanisms, Larissa L. Dougherty

Dartmouth College Ph.D Dissertations

Cilia are structures present on most eukaryotic cells which provide important signaling and motile components to cells from early development to fully differentiated and matured cells. Regulation of these structures is critical to proper functioning of the cell and is known to be tied to the cell cycle. Preparation for ciliary assembly following cell cycle exit and ciliary disassembly following cell cycle reentry requires components throughout the cell body and within the cilium to facilitate this process. Here I identify how the cell adapts to ensure modifications to cilia occur for assembly or disassembly using the model organism Chlamydomonas reinhardtii. …

Rab35 Centered Membrane Trafficking Pathway Directs Apical Constriction During Drosophila Gastrulation, Hui Miao

Electronic Theses and Dissertations

Force generation in epithelial tissues is often pulsatile, with actomyosin networks generating high-tension contractile forces at the cell cortex before cyclically disassembling. This pulsed nature of cytoskeletal forces implies that there must be cellular processes to extract unidirectional changes that drive processive transformations in cell shape. During Drosophila melanogastergastrulation, the invagination of the prospective mesoderm is driven by the pulsed constriction of apical surfaces. Here, we address the mechanisms by which the irreversibility of pulsed events is achieved while also permitting uniform epithelial behaviors to emerge. We use MSD-based analyses to identify contractile steps and find that when a …

Dissecting The Cellular Control Of Septin Organization In A Global Cereal Killer, Nawaraj Dulal

Graduate Theses and Dissertations

Rice blast disease, caused by the filamentous fungus Magnaporthe oryzae, destroys sufficient rice each year to feed 60 million people, and is a serious threat to global food security. A wheat-adapted lineage of M. oryzae now poses threat to global wheat production. Rice blast disease is currently controlled using limited fungicides, and the emergence of fungicide resistance within M. oryzae populations is a growing concern. There is a pressing need to identify new classes of fungicides to control the disease, which requires better understanding of the basic biology of the pathogen. To establish disease, M. oryzae forms a specialized dome …

Cargo Transport By Myosin Va Molecular Motors Within Three-Dimensional In Vitro Models Of The Intracellular Actin Cytoskeletal Network, Andrew Thomas Lombardo

Graduate College Dissertations and Theses

Intracellular cargo transport involves the movement of critical cellular components (e.g. vesicles, organelles, mRNA, chromosomes) along cytoskeletal tracks by tiny molecular motors. Myosin Va motors have been demonstrated to play a vital role in the transport of cargos destined for the cell membrane by navigating their cargos through the three-dimensional actin networks of the cell. Transport of cargo through these networks presents many challenges, including directional and physical obstacles which teams of myosin Va-bound to a single cargo must overcome. Specifically, myosin Va motors are presented with numerous actin-actin intersections and dense networks of filaments which can act as a …

Characterizing The Inhibition Of Katanin Using Tubulin Carboxy-Terminal Tail Constructs, Corey E. Reed

Masters Theses

Understanding how the cellular cytoskeleton is maintained and regulated is important to elucidate the functions of many structures such as the mitotic spindle, cilia and flagella. Katanin p60, microtubule-severing enzymes from the ATPase associated with cellular activities (AAA+) family, has previously been shown in our lab to be inhibited by free tubulin as well as α- and β-tubulin carboxy-terminal tail (CTT) constructs. Here we investigate the inhibition ability of several different tubulin CTT sequences. We quantify the effect of the addition of these constructs on the severing and binding activity of katanin. We find that some constructs inhibit katanin better …

The Function Of Carmil1 In Migrating Cells, Marc Edwards

All Theses and Dissertations (ETDs)

This dissertation describes the physiological role of the Capping Protein- CARMIL interaction in migrating cells. I establish the CARMIL-CP complex as a key regulator of lamellipodial actin assembly and of lamellipodial dynamics. Membrane ruffling at the leading edge of motile cells and macropinocytosis were also found to be dependent on the CARMIL1-CP interaction. This is consistent with macropinocytosis and ruffling being dependent on a functional and dynamic lamellipodium.: Kerr and Teasdale, 2009).

In chapter two I demonstrate that the CBR of CARMIL1 is competent to inhibit CP in cells. I show that overexpression of the CBR in cells leads to …

Frazzled And Abelson Interact To Regulate The Actin Cytoskeleton In Drosophila, Bridget Elsa Varughese

Wayne State University Dissertations

Guidance receptors such as Frazzled affect cell shape and motility by directly or indirectly modulating the cytoskeleton. Fra is particularly needed for the formation of the posterior commissures in a developing Drosophila embryo. The cytoplasmic tyrosine kinase, Abelson Kinase (Abl) enhances the loss of commissures observed in fra mutant. Abl physically interacts with Frazzled to help guide commissural axons across the midline. Furthermore, the loss of commissural axons is only seen when the actin dynamics are perturbed. Abl is also known to regulate actin-dependent processes underlying formation of filopodia, microspikes and membrane ruffles. So, we established a Drosophila S2 cell …