First Thursday Art Walk of Pioneer Square: A Case Study

First Thursday Gallery Walk in Seattle’s Pioneer Square neighborhood was established in the early 1980s to increase visibility of the art galleries in the neighborhood. What started as a collector-based event evolved into an event for a broader public audience, where locals and tourists visit the galleries to learn about and engage with the art presented. The Pioneer Square gallerists worked in cooperation to establish the event and a monthly printed publication that announces the shows opening on each First Thursday. As Pioneer Square and the city of Seattle change in infrastructure, population, and size, First Thursdays live on as a public event for the public to experience art

Francine Seders Gallery: A Case Study

The Francine Seders Gallery was an important player in the Seattle art scene from the 1960s until its close in 2013. Seders ran her gallery with a low key, unintimidating sales approach, welcoming artists, art enthusiasts, collectors, and students to her space to indulge in the enjoyment of the art. The Francine Seders Gallery represented well-known, established, and developing artists such as Jacob Lawrence, Michael Spafford, Mark Tobey, Barbara Earl Thomas, Marita Dingus, and Alan Lau. Years later, the Francine Seders Gallery is remembered as an industry standard, as many gallerists continue to seek her advice and influence

Inducible Protein Dimerization: New Tools and Applications to Understanding the Mitotic Checkpoint

Cellular processes such as growth, migration, signaling and cell division require choreographed interactions between dozens or hundreds of proteins carefully organized in time and space. In order to test hypotheses about complex cellular functions, it is desirable to experimentally perturb the interactions of individual proteins that perform these functions with a level of spatial and temporal control commensurate with the time and space scales over which the system is naturally organized. Inducible protein dimerization offers the ability to experimentally control protein-protein interactions. Inducible dimerization can be used to test the immediate effects of dimerizing two proteins, or it can be engineered to create or destroy a protein or change a protein\u27s localization. Several different techniques for inducible dimerization using small molecules or light have been developed, each with its own strengths and weaknesses. Ultimately, only light-inducible dimerization offers the potential for both temporal and spatial experimental control. In this thesis, I describe the application of inducible dimerization to further our understanding of a complex signaling network, the Mitotic Checkpoint, which monitors chromosome segregation and is regulated by the localization of its constituent checkpoint proteins. I discovered that relocalizing a single key checkpoint protein, Mad1, to kinetochores at metaphase is sufficient to reactivate the checkpoint. I also describe the development of a novel photochemical technique which has allowed us to achieve light-induced dimerization at centromeres, a cellular compartment which has not been successfully targeted by previously reported light-inducible dimerization systems. This technology enables us to perform experimental biology on living cells with a new level of spatial and temporal control

On a property of random-oriented percolation in a quadrant

Grimmett's random-orientation percolation is formulated as follows. The square lattice is used to generate an oriented graph such that each edge is oriented rightwards (resp. upwards) with probability $p$ and leftwards (resp. downwards) otherwise. We consider a variation of Grimmett's model proposed by Hegarty, in which edges are oriented away from the origin with probability $p$, and towards it with probability $1-p$, which implies rotational instead of translational symmetry. We show that both models could be considered as special cases of random-oriented percolation in the NE-quadrant, provided that the critical value for the latter is 1/2. As a corollary, we unconditionally obtain a non-trivial lower bound for the critical value of Hegarty's random-orientation model. The second part of the paper is devoted to higher dimensions and we show that the Grimmett model percolates in any slab of height at least 3 in $\mathbb{Z}^3$.Comment: The abstract has been updated, discussion has been added to the end of the articl

Optogenetic control of organelle transport using a photocaged chemical inducer of dimerization

SummaryCell polarity, growth and signaling require organelle transport by cytoskeletal motor proteins that are precisely regulated in time and space. Probing these complex, dynamic processes requires experimental techniques with comparable temporal and spatial precision. Inducible dimerization offers the ability to recruit motor proteins to organelles in living cells. Approaches include rapamycin-induced dimerization of motors and cargo-bound binding partners [1] or the recent application of the TULIP light-inducible dimerization system [2,3]. In the latter system, motor recruitment is activated by blue light, and relaxes to an OFF state in the dark within seconds. While rapid relaxation is desirable for some applications, many experiments require sustained motor recruitment. Here, we use a photocaged chemical dimerizer to achieve sustained, spatially-defined motor recruitment to individual organelles with a single pulse of light. We demonstrate the general applicability of the system by recruiting microtubule plus end-directed kinesin-1 and minus end-directed dynein motors to peroxisomes and mitochondria in HeLa cells and primary neurons, leading to alterations in organelle transport on timescales from <10 seconds to >10 minutes after photoactivation

Student Registered Nurse Anesthetists: The Impact of Structured High Fidelity Simulation on Anesthesia Ready Time

Introduction: Student registered nurse anesthetists (SRNAs) at a large academic medical center are limited in clinical training experiences owing to the subjective perception by local anesthesia department administrators of decreased oper-ating room efficiency with SRNA involvement. The purpose of this project was to utilize structured high-fidelity simula-tion (HFS) to increase basic skill proficiency in SRNAs and evaluate the impact of the simulation within the first month of clinical training.Methods: Utilizing the Iowa Model of Evidence-Based Practice to Promote Quality Care, a 5-week structured HFS program was inserted into the nurse anesthesia curriculum before the SRNAs’ first clinical rotation. The program pro-moted basic anesthesia skill proficiency through the assimilation of previously taught and tested technical skills. In-room times and anesthesia ready times of all SRNA cases involving general anesthesia with the placement of an endotrache-al tube during September 2012 and 2013 were compiled by use of retrospective chart review. Using the calculation of elapsed time between in-room time and anesthesia ready time (IRTART), the clinical performance of 2 consecutive classes of SRNAs was compared, one with structured HFS training and one without.Results: The mean IRTART for both groups was similar at 20 minutes with a standard deviation of 10 minutes. The IRTARTs from both groups were within the institution’s operative norm.Conclusion: Structured HFS did not impact the anesthesia ready time of new-to-practice SRNAs. However, the in-formation collected during implementation of HFS and data analysis can be used to develop future avenues to improve current processes for structured HFS and clinical training opportunities

Insights into the molecular architecture of a peptide nanotube using FTIR and solid-state NMR spectroscopic measurements on an aligned sample

The self-assembly of proteins and peptides into b-sheet-rich amyloid fibers is a process that has gained notoriety because of its association with human diseases and disorders. Spontaneous self-assembly of peptides into nonfibrillar supramolecular structures can also provide a versatile and convenient mechanism for the bottom-up design of biocompatible materials with functional properties favoring a wide range of practical applications.[1] One subset of these fascinating and potentially useful nanoscale constructions are the peptide nanotubes, elongated cylindrical structures with a hollow center bounded by a thin wall of peptide molecules.[2] A formidable challenge in optimizing and harnessing the properties of nanotube assemblies is to gain atomistic insight into their architecture, and to elucidate precisely how the tubular morphology is constructed from the peptide building blocks. Some of these fine details have been elucidated recently with the use of magic-angle-spinning (MAS) solidstate NMR (SSNMR) spectroscopy.[3] MAS SSNMR measurements of chemical shifts and through-space interatomic distances provide constraints on peptide conformation (e.g., b-strands and turns) and quaternary packing. We describe here a new application of a straightforward SSNMR technique which, when combined with FTIR spectroscopy, reports quantitatively on the orientation of the peptide molecules within the nanotube structure, thereby providing an additional structural constraint not accessible to MAS SSNMR

Biochemical analysis of TssK, a core component of the bacterial Type VI secretion system, reveals distinct oligomeric states of TssK and identifies a TssK–TssFG subcomplex

Gram-negative bacteria use the Type VI secretion system (T6SS) to inject toxic proteins into rival bacteria or eukaryotic cells. However, the mechanism of the T6SS is incompletely understood. In the present study, we investigated a conserved component of the T6SS, TssK, using the antibacterial T6SS of Serratia marcescens as a model system. TssK was confirmed to be essential for effector secretion by the T6SS. The native protein, although not an integral membrane protein, appeared to localize to the inner membrane, consistent with its presence within a membrane-anchored assembly. Recombinant TssK purified from S. marcescens was found to exist in several stable oligomeric forms, namely trimer, hexamer and higher-order species. Native-level purification of TssK identified TssF and TssG as interacting proteins. TssF and TssG, conserved T6SS components of unknown function, were required for T6SS activity, but not for correct localization of TssK. A complex containing TssK, TssF and TssG was subsequently purified in vitro, confirming that these three proteins form a new subcomplex within the T6SS. Our findings provide new insight into the T6SS assembly, allowing us to propose a model whereby TssK recruits TssFG into the membrane-associated T6SS complex and different oligomeric states of TssK may contribute to the dynamic mechanism of the system

Extraocular, rod-like photoreceptors in a flatworm express xenopsin photopigment

Animals detect light using opsin photopigments. Xenopsin, a recently classified subtype of opsin, challenges our views on opsin and photoreceptor evolution. Originally thought to belong to the Gαi-coupled ciliary opsins, xenopsins are now understood to have diverged from ciliary opsins in pre-bilaterian times, but little is known about the cells that deploy these proteins, or if they form a photopigment and drive phototransduction. We characterized xenopsin in a flatworm, Maritigrella crozieri, and found it expressed in ciliary cells of eyes in the larva, and in extraocular cells around the brain in the adult. These extraocular cells house hundreds of cilia in an intra-cellular vacuole (phaosome). Functional assays in human cells show Maritigrella xenopsin drives phototransduction primarily by coupling to Gαi. These findings highlight similarities between xenopsin and c-opsin and reveal a novel type of opsin-expressing cell that, like jawed vertebrate rods, encloses the ciliary membrane within their own plasma membrane

Mammalian kinetochores count attached microtubules in a sensitive and switch-like manner.

The spindle assembly checkpoint (SAC) prevents anaphase until all kinetochores attach to the spindle. Each mammalian kinetochore binds many microtubules, but how many attached microtubules are required to turn off the checkpoint, and how the kinetochore monitors microtubule numbers, are not known and are central to understanding SAC mechanisms and function. To address these questions, here we systematically tune and fix the fraction of Hec1 molecules capable of microtubule binding. We show that Hec1 molecules independently bind microtubules within single kinetochores, but that the kinetochore does not independently process attachment information from different molecules. Few attached microtubules (20% occupancy) can trigger complete Mad1 loss, and Mad1 loss is slower in this case. Finally, we show using laser ablation that individual kinetochores detect changes in microtubule binding, not in spindle forces that accompany attachment. Thus, the mammalian kinetochore responds specifically to the binding of each microtubule and counts microtubules as a single unit in a sensitive and switch-like manner. This may allow kinetochores to rapidly react to early attachments and maintain a robust SAC response despite dynamic microtubule numbers