Dynamic mitochondrial transport into axons and dendrites of neuronal cells is critical for sustaining neuronal excitability, synaptic transmission, and cell survival. Failure of mitochondrial transport is the direct cause of some neurodegenerative diseases, and an aggravating factor for many others. Mitochondrial transport regulation involves many proteins; factoring prominently among them are the atypical mitochondrial GTPase Miro and the Milton/TRAK adaptor proteins, which link microtubule (MT) motors to mitochondria. Motors of the kinesin family mediate mitochondrial transport towards the plus ends of microtubules, while motors of the dynein family mediate mitochondrial transport towards the minus ends. Selective use of these motors determines the ultimate subcellular distribution of mitochondria, but the underlying control mechanisms remain poorly understood. Drosophila Miro (dMiro) is required for kinesin-driven transport of mitochondria, but its role in dynein-driven transport remains controversial. In Chapter 2 of this study, I show that dMiro is also required for the dynein-driven transport of mitochondria. In addition, we used the loss-of-function mutations dMiroT25N and dMiroT460N to analyze the function of dMiro's N- and C-terminal GTPase domains, respectively. We show that dMiroT25N causes lethality and impairs mitochondrial distribution and transport in a manner indistinguishable from dmiro null mutants. Our analysis suggests that both kinesin- and dynein-driven mitochondrial transport require the activity of Miro's N-terminal GTPase domain, which likely controls the transition from a stationary to a motile state irrespective of the transport direction. dMiroT460N reduced only dynein motility during retrograde axonal transport but had no effect on distribution of mitochondria in neurons, indicating that the C-terminal GTPase domain of Miro most likely has only a small modulatory role on transport. Furthermore, we show that commonly used substitutions in Miro's GTPase domains, based on the constitutively active Ras-G12V mutation, appear to cause neomorphic phenotypic effects which are probably unrelated to the normal function of the protein. In mammalian neurons, kinesin and dynein motors are linked to mitochondria via a Miro complex with the adapter proteins TRAK1 and TRAK2, respectively. Differential linkage of TRAK-motor complexes provides a mechanism for determining the direction of transport and controlling mitochondrial distributions within the cell. Drosophila has only one TRAK gene homolog, Milton, which expresses several protein isoform. Milton has been previously been shown to facilitate mitochondrial transport by binding to kinesin and dMiro, a role analogous to TRAK1. However, the question whether Milton might be able mediate dynein-based transport in a manner similar to TRAK2 has remained unknown. In Chapter 3 of this study, I show that protein isoforms A and B of Milton, generated through alternative mRNA splicing, facilitate differential motor activities analogous to mammalian TRAKs. Specifically, overexpression (OE) of Milton-A caused a mitochondrial redistribution and accumulation at axon terminals, which requires kinesin-driven MT plus end directed transport; while OE of Milton-B caused a redistribution of axonal mitochondria into the soma, which requires dynein-driven MT minus end directed transport. I further show that Milton-motor complex binding to mitochondria requires Miro exclusively, and that transport with either of the motor complexes absolutely requires the activity of Miro's N-terminal GTPase domain. Together, these results suggest that Miro controls the transition of mitochondria from a stationary to a motile phase. Thereafter the direction of transport is likely determined by an alternative binding of opposing Milton/TRAK-motor complexes to Miro, a process which appears to be regulated by a Miro-independent mechanism.

Microtubule-based mitochondrial transport into dendrites and axons is vital for sustaining neuronal function. Transport along microtubules proceeds in a series of plus- and minus-end directed movements facilitated by kinesin and dynein motors. How the opposing movements are controlled to achieve effective long distance transport remains unclear. Previous studies showed that the conserved mitochondrial GTPase Miro is required for mitochondrial transport into axons and dendrites. To directly examine Miro's significance for kinesin- and/or dynein-mediated mitochondrial motility, we live imaged movements of GFP-tagged mitochondria in larval Drosophila motor axons upon genetic manipulations of Miro. Loss of Drosophila Miro (dMiro) reduced the effectiveness of either antero- or retrograde mitochondrial transport by selectively impairing kinesin- or dynein-mediated movements, depending on the direction of net transport. In both cases, the duration of short stationary phases increased proportionally. Overexpression (OE) of dMiro also impaired the effectiveness of mitochondrial transport. Finally, loss and OE of dMiro altered the length of mitochondria in axons through a mechanistically separate pathway. We concluded that dMiro promotes effective antero- and retrograde mitochondrial transport by extending the processivity of kinesin and dynein motors according to a mitochondrion's programmed direction of transport. To determine how Miro achieves this control mechanistically, we introduced point mutations that render each GTPase either constitutively active or inactive. Expression of either first GTPase mutant impaired antero- (inactive) or retrograde motor movements (active) in a direction dependent manner. The active state of the second GTPase domain up-regulated the number of consecutive kinesin motions during anterograde transport but impaired kinesin transport biases while the inactive second GTPase state impaired transport in either direction. Together, these data suggest that Miro's first GTPase domain is major factor that controls the execution of either the antero- or retrograde directional program while Miro's second GTPase may provide a signal that supports or disfavors transport. In addition, the active state of the first and the second GTPase domain increased the length of stationary mitochondria but only the first GTPase domain modified motile mitochondrial lengths. Overexpression of these mutations generated opposing effects. We conclude that both domains control antero- and retrograde transport in a switch-like manner.

Neurons are metabolically active cells that depend on mitochondria for ATP production and calcium homeostasis. Within a single neuron, the demand for mitochondrial function is highly variable both spatially and temporally. This need-based distribution is reflected in high local density of mitochondria at presynaptic endings, post-synaptic densities, nodes of Ranvier, and in growth cones, where mitochondrial function is required to sustain neuronal activity. To meet local demand, mitochondria are mobile organelles that move along microtubule cytoskeleton in axons and dendrites. Due to their role in oxidative phosphorylation, mitochondria are prone to oxidative damage that can in turn jeopardize the cell. To minimize cellular damage, an autophagic process, known as mitophagy, has evolved to clear dysfunctional mitochondria. Defects in mitochondrial clearance are implicated in neurodegenerative diseases such as Parkinson's disease (PD). In neurons, it was thought that mitochondria with reduced membrane potential are retrogradely transported to the soma where they are degraded. In this dissertation, I present a new paradigm where damaged mitochondria are arrested and undergo mitophagy locally in axons. In chapter 2 we report that mitochondrial damage causes arrest of mitochondrial motility in neuronal axons through the action of Parkin, an E3 ubiquitin ligase implicated in PD. Parkin accumulates on the surface of depolarized mitochondria and triggers proteosomal degradation of the mitochondrial motor adaptor protein, Miro, thereby detaching mitochondria from the kinesin and dynein motor complex. This arrest of mitochondria would serve to quarantine them in preparation for their subsequent degradation. In chapter 3, I demonstrate that damage to a small population of axonal mitochondria triggers a pathway of mitophagy that occurs locally in distal axons. Two PD-associated proteins, PINK1, a mitochondrial kinase mutated, and Parkin are both required for axonal mitophagy. In chapter 4, I present preliminary studies examining the turnover rate of neuronal PINK1 in order to characterize its mechanism of activation in distal axons. In conclusion, I have characterized a pathway for quality control of mitochondria in neuronal axons showing that clearance of defective mitochondria oocurs locally in distal axons without a need for their retrograde transport to the soma.

<p>The Ras superfamily of GTPases embraces six major branches of proteins: the Ras, Rab, Ran, Arf, Rho and Miro subfamilies. The majority of GTPases function as binary switches that cycle between active GTP-bound and inactive GDP-bound states. This thesis will focus primarily on the biological functions of the Rho and Miro proteins. The Rho GTPases control the organization of the actin cytoskeleton and other associated activities, whereas the Miro GTPases are regulators of mitochondrial movement and morphology. </p><p>A diverse array of cellular phenomena, including cell movement and intracellular membrane trafficking events, are dependent on cytoskeletal rearrangements mediated by Rho GTPases. Although human Rho GTPases are encoded by 20 distinct genes, most studies involving Rho GTPases have focused on the three representatives RhoA, Rac1 and Cdc42, which each regulate specific actin-dependent cellular processes. In an effort to compare the effects of all Rho GTPase members in the same cell system, we transfected constitutively active Rho GTPases in porcine aortic endothelial (PAE) cells and examined their effects on the organization of the actin cytoskeleton. We identified a number of previously undetected roles of the different members of the Rho GTPases. Moreover, we demonstrated that the downstream effectors of Rho GTPases have a broader specificity than previously thought. </p><p>In a screen for novel Ras-like GTPases, we identified the Miro GTPases (Mitochondrial Rho). In our characterization of Miro, we established that these proteins influence mitochondrial morphology and serve functions in the transport of mitochondria along the microtubule system. Additionally, we provided evidence that Miro can be under control of calcium signaling pathways. Mitochondria are highly dynamic organelles that undergo continuous change in shape and distribution. Defects in mitochondrial dynamics are associated with several neurodegenerative diseases. In conclusion, our findings have contributed to a deeper understanding of the biological roles of Rho and Miro GTPases.</p>

The Ras superfamily of GTPases embraces six major branches of proteins: the Ras, Rab, Ran, Arf, Rho and Miro subfamilies. The majority of GTPases function as binary switches that cycle between active GTP-bound and inactive GDP-bound states. This thesis will focus primarily on the biological functions of the Rho and Miro proteins. The Rho GTPases control the organization of the actin cytoskeleton and other associated activities, whereas the Miro GTPases are regulators of mitochondrial movement and morphology. A diverse array of cellular phenomena, including cell movement and intracellular membrane trafficking events, are dependent on cytoskeletal rearrangements mediated by Rho GTPases. Although human Rho GTPases are encoded by 20 distinct genes, most studies involving Rho GTPases have focused on the three representatives RhoA, Rac1 and Cdc42, which each regulate specific actin-dependent cellular processes. In an effort to compare the effects of all Rho GTPase members in the same cell system, we transfected constitutively active Rho GTPases in porcine aortic endothelial (PAE) cells and examined their effects on the organization of the actin cytoskeleton. We identified a number of previously undetected roles of the different members of the Rho GTPases. Moreover, we demonstrated that the downstream effectors of Rho GTPases have a broader specificity than previously thought. In a screen for novel Ras-like GTPases, we identified the Miro GTPases (Mitochondrial Rho). In our characterization of Miro, we established that these proteins influence mitochondrial morphology and serve functions in the transport of mitochondria along the microtubule system. Additionally, we provided evidence that Miro can be under control of calcium signaling pathways. Mitochondria are highly dynamic organelles that undergo continuous change in shape and distribution. Defects in mitochondrial dynamics are associated with several neurodegenerative diseases. In conclusion, our findings have contributed to a deeper understanding of the biological roles of Rho and Miro GTPases.

Denna studie fokuserar på utvecklingen av en interaktiv chatbot för att underlätta valet av kommunikationsenheter för personer med alternativa och kompletterande kommunikationsbehov (AKK). Genom att integrera MIRO för att skapa beslutsträd och Flowchart AI för att konstruera chatbotar möjliggörs en strukturerad process för visualisering och implementering av innehåll på en webbplattform. Beslutsträdet, konstruerat i MIRO, identifierar och strukturerar olika komponenter som är nödvändiga för att skapa en skräddarsydd enhet för varje individ inom AKK-kategorin. Flowchart AI används för att utveckla en interaktiv chatbot som vägleder valet av enhet, mjukvara och tillbehör baserat på användarens specifika behov och preferenser. Studien inkluderar även prototyper av e-postmeddelanden för att förse användarna med en sammanfattning av rekommendationerna. Slutresultatet av detta arbete innebär framgångsrik utveckling av en interaktiv chatbot som guidar användare genom valet av lämpliga Tobii Dynavox-produkter, skräddarsytt efter deras individuella behov. Genom att erbjuda användarna en mer effektiv och riktad rekommendationsprocess sparar arbetet både tid och resurser för såväl användare som professionella, som logopeder. Projektet bidrar till förbättrad tillgång till information och vägledning inom detta område, vilket främjar ökad tillgänglighet och effektivitet inom alternativa och kompletterande kommunikationslösningar. Vidare har projektet främjat kunskapsutvecklingen inom området genom att utveckla ett interaktivt program för medicinteknisk utrustning. Ur ett bredare samhällsperspektiv har arbetet också bidragit till ökad tillgänglighet och effektivitet inom alternativ och kompletterande kommunikation, vilket kan förbättra livskvaliteten för personer som behöver dessa lösningar. Arbetet har minskat risken för felaktiga val och ökat användarnas förmåga att kommunicera effektivt och självständigt. / This study focuses on the development of an interactive chatbot to facilitate the selection of communication devices for individuals with alternative and augmentative communication (AAC) needs. By integrating MIRO for creating decision trees and Flowchart AI for constructing the chatbot, a structured process for visualizing and implementing content on a web platform is enabled.  The decision tree, constructed in MIRO, identifies and organizes various components necessary to create a customized device for each individual within the AAC category. Flowchart AI is utilized to develop an interactive chatbot that guides users through the selection of device, software, and accessories based on their specific needs and preferences. The study also includes prototypes of email notifications to provide users with a summary of recommendations. The culmination of this work results in the successful development of an interactive chatbot that guides users through the selection of suitable Tobii Dynavox products tailored to their individual needs. By offering users a more efficient and targeted recommendation process, the work saves time and resources for both users and professionals, such as speech therapist. The project contributes to improved access to information and guidance in this area, promoting increased accessibility and efficiency in alternative and augmentative communication solutions. Furthermore, the project has promoted knowledge development in the field by creating an interactive program for medical equipment. From a broader societal perspective, the work has also contributed to increased accessibility and efficiency in alternative and augmentative communication, potentially enhancing the quality of life for individuals in need of these solutions. The work has reduced the risk of erroneous choices and enhanced users' ability to communicate effectively and independently.

Researches on biological adhesive systems in nature have changed a perspective view on adhesion that it is not only the area of surface chemistry, but also mechanics of interfacial geometry which can significantly effect on fracture strength and load distribution on the contact interface. Various synthetic fibrillar adhesives in previous works have shown enhanced interfacial bond strength with the capacity of adhesion control by exploiting mechanical deformation of the elastomeric fibrillar structures inspired by geckos. However, control of the interfacial load distribution has been focused on the size of micro-contact with single or a few of micro-/nano-fibers on planar surface, and not for a large contact area on complex three-dimensional (3D) surfaces. This thesis work aims at investigating principles of the interfacial load distribution control in multi-scale, ranging from micro-contact with single micro-fiber to a centimeter-scale contact with a membrane-backed micro-fiber array on non-planar 3D surfaces. The findings are also applied for developing a soft robotic gripper capable of grasping a wide range of complex objects in size, shape, and number, expanding the area of practical applications for bio-inspired adhesives in transfer printing, robotic manipulators, and mobile robots. This paper comprises three main works. First, we investigate the effect of tip-shapes on the interfacial load sharing of mushroom-shaped micro-fibrillar adhesives with precisely defined tipgeometries using high resolution 3D nano-fabrication technique. For a large area of non-planar contact interface, we fabricate fibrillar adhesives on a membrane (FAM) by integrating micro-fibers with a soft backing, which enables robust and controllable adhesion on 3D surfaces. Picking and releasing mechanism for the maximal controllability in adhesion are discussed. Finally, we propose a soft robotic architecture which can control the interfacial load distribution for the FAM on 3D surfaces, solving an inherit dilemma between conformability and high fracture strength with the equal load sharing on complex non-planar 3D surfaces.

xii, 169 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Medieval Aquitaine was a vibrant region in terms of its politics, religion, and culture, and these interrelated aspects of life created a fertile environment for musical production. A rich manuscript tradition has facilitated numerous studies of Aquitanian sacred music, but to date most previous research has focused on one particular facet of the repertoire, often in isolation from its cultural context. This study seeks to view Aquitanian musical culture through several intersecting sacred and secular concerns and to relate the various musical traditions to the region's broader societal forces. Saint-Martial in Limoges and Toulouse, two musical and cultural centers, illustrate the wider cultural context in Aquitaine, and a survey of select manuscripts shows the development of a musical tradition. An examination of three disparate pieces shows that the repertoire as a whole is a more unified part of Aquitanian culture than previously recognized. / Committee in Charge: Dr. Lori Kruckenberg, Chair; Dr. Marc Vanscheeuwijck; Dr. Marian Smith

This dissertation explores the presence and meaning of astronomical elements in the creative work of Surrealist artists and writers who were involved with the movement from the 1920s to the 1940s. Set against a backdrop of widespread popular interest in astronomy in France during these decades and those directly preceding them, Surrealists such as André Breton, Joan Miró, Max Ernst, Wolfgang Paalen, Oscar Domínguez, Matta, Remedios Varo, Leonora Carrington, and Kurt Seligmann all addressed cosmic themes in their artistic production. This dissertation identifies and analyzes their varied engagement with such themes, including their presence in the related areas of astrology and the Tarot. The heavens offered the Surrealists a rich terrain for invention—one that could be seen as scientific or occult, fanciful or factual, as well as ancient or up-to-date. In their quest to access previously unknown realms of reality, the Surrealists found in the little-explored and often strange territory of outer space a new realm for creative invention. As such, these artists and writers projected their surreal visions onto the universe in their continued search for the marvelous. / text

The decline in range and density of many native New Zealand birds from mammalian predation has raised concerns over the functioning of ecosystem processes such as pollination and seed dispersal. At Maungatautari, almost all mammalian pests have been eradicated from within a pest-proof fence enclosing 3400 ha of native forest. I examined whether Maungatautari is restoring pollination and seed dispersal services to native plants, compared to a nearby non-treatment site, Pirongia Mountain. Five-minute bird counts made at Maungatautari and Pirongia (in 2002 and 2005 prior to pest eradication from Maungatautari, and in 2008 and 2010 following eradication) indicated that 10 of the 12 individual bird species examined showed significant changes in abundance following pest control. Six species showed an increase in abundance, including bellbirds (Anthornis melanura), tui (Prosthemadera novaeseelandiae) and kereru (Hemiphaga novaeseelandiae). Counts of all native species combined increased at Maungatautari while counts of all exotic species showed no trend over count years. In December 2010, 140 five-minute bird counts showed tui and bellbirds, key pollinators, to be more abundant at Maungatautari than Pirongia. Higher pollen loads on the stigmas of both female and hermaphrodite Fuchsia excorticata flowers at Maungatautari, compared to Pirongia, suggest that F. excorticata at Maungatautari received better pollination service. Fuchsia excorticata pollen loads collected from 67 sites around New Zealand indicate that female plants at sites with lower abundances of mammalian predators generally received better pollination service. Hermaphrodite F. excorticata plants had similar and high pollen scores in all regions, except for in the North Island. Five-minute bird counts in December 2010 also showed that kereru and blackbirds (Turdus merula), key seed dispersers along with tui and bellbirds, were more abundant at Maungatautari than Pirongia. A second measure of bird abundance, maximum counts, showed flock sizes of tui, bellbirds and kereru were larger at Maungatautari, but only significantly so for tui and bellbirds. Fuchsia excorticata fruits were removed more rapidly from plants at Maungatautari than at Pirongia (a 6-fold difference). There was twice the density of tawa fruits (bird cleaned and fleshy) under trees at Maungatautari compared to Pirongia, perhaps from reduced mammalian fruit predation. There was no significant site effect on tawa dispersal service (percent of fruit consumed by birds), but a significant site x fruit density interaction, suggests birds at Maungatautari provided better dispersal service to large fruit crops. A similar number of miro fruit (bird cleaned and fleshy) were caught in seed traps under miro trees, but a greater percentage of fruits were consumed by birds at Maungatautari (59%) compared to Pirongia (26%). The results from this thesis indicate that increased densities of key native birds at Maungatautari are providing better pollination and dispersal services to the native plants examined. Projects which increase the density of key bird mutualists, such as tui, bellbirds and kereru, on the mainland, may have positive benefits for pollination and seed dispersal mutualisms.