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α-Synuclein Aggregation in Alternative States of Sphingolipid Metabolism in a Caenorhabditis elegans Model of Parkinson’s Disease
No full textα-synuclein is a neuronal protein that is a major aggregative component of Lewy body plaques associated with Parkinson’s disease, as well as other neurodegenerative diseases. While α-synuclein forms these amyloid-like fibrillar protein aggregates, it is not known whether these fibrils are the primary cause of cellular toxicity. Alternatively, intermediate oligomer species that form between monomer and fibrillar conformations have been shown to be toxic, though they have not been confirmed to form naturally in vivo. In this study, the aggregation of α-synuclein in a C. elegans model of Parkinson’s disease is characterized by semidenaturing detergent-agarose gel electrophoresis (SDD-AGE). α-synuclein tetramers or higher order oligomers were observed to form when expressed in C. elegans. How conditions of worsened aggregation might be reflected in the SDD-AGE profile of α-synuclein was also investigated. To do so, enzymes involved in sphingolipid synthesis were targeted by RNAi knockdown and pharmacological inhibition since other work has suggested a role for sphingolipids in suppressing α-synuclein aggregation. However, no observable difference in the aggregation of α-synuclein in worms was induced by these treatments. Nevertheless, further characterization of the species observed by SDD-AGE may inform drug discovery to target the relevant biochemistry involved in disease-associated aggregation
Physiology and anatomy of medullosan foliage from the Late Carboniferous Illinois Basin, U.S.A.
No full textPlant physiology often yielded important insights on the biomechanical functions of plants and plant-environment interactions through time. This paper investigated the physiology and anatomy of a group of extinct, Late Carboniferous pteridosperms, the medullosans. The aim was to examine how patterns of variation in leaf venation within medullosan foliage, as quantified by leaf vein density, might inform about the physiology of medullosans and interactions between medullosans and the external environment. In contrast to stomatal and stem hydraulic conductivity, previously known to be high, the leaf vein density of medullosans from the Illinois Coal Basin, U.S.A. was within a fairly low range between 1-3 mm leaf vein/mm2 leaf area across 5.5 million years. Low leaf vein density with high hydraulic conductivity suggested leaf adaptations to meet evapotranspiration demands. The stability of leaf vein density observed suggested that leaf vein density alone couldn’t serve as a paleoenvironmental proxy, highlighting the importance of whole-plant functional modeling
Creating Photoconductive Protein-Porphyrin Nanowires from Natural and Engineered Proteins PilA and PP1K
No full textElectronically active biomaterials have myriad applications in the design of medical implants, drug delivery, and nanotechnology. The unique photo-electronic properties of porphyrin makes it a promising basis of electronic biomaterials design, as aligned porphyrin molecules under an applied voltage can engage in linear electron transfer when photo-excited, resulting in an electric current. Self-assembling peptide fibers may serve as effective scaffolds for porphyrin, allowing for the production of photo-electronic peptide-porphyrin nanowires. We are working currently with two peptides to serve as porphyrin scaffolds. The first is synthetic peptide PP1K, which self-assembles into coiled-coil fibers through the formation of disulfide bonds at pH 8.3 and can bind Meso-tetra (4-sulfonatophenyl) porphine (TPPS4) via charged lysine residues. The conductivity of these fibers with and without laser excitation was measured on micropatterned interdigitated electrodes at varying humidity levels in a humidity-controlled chamber. PP1K + TPPS4 fibers showed no photocurrent at 5% and 35% humidity, and a small photocurrent at 80% humidity (0.07 ± 0.013 pA), yet this photocurrent was no greater than controls measuring fibers alone and bare electrodes. Thus PP1K + TPPS4 fibers are not photoconductive with current preparation methods, yet different protocols are still being investigated. The second system we are working with is a naturally occurring protein PilA, produced by anaerobic bacteria Geobacter sulfurreducens to form long, electrically conductive pili fibers that reduce iron (III) oxides. PilA has been successfully expressed and purified from E. coli as a fusion protein with TrpLE. We have cleaved PilA from this fusion and confirmed its identity with MALDI mass spectrometry. To attempt to induce fiber formation, PilA in 6 M guanidine-HCl was dialyzed towards TPPS4 to simultaneously remove denaturing agent and introduce porphyrin, yet this failed to yield secondary structure or visible fibers. Further attempts to induce fiber formation will introduce monomer to buffer conditions with varying pH and salt concentrations
Radical Practice and "Real Hustle": Neoliberalism from Below in a South African Township
No full textMore than twenty years after the end of apartheid, many of the promises of popular \ud
democracy and liberation remain unfulfilled for black South Africans. The continuing \ud
economic and social inequalities in the cities of South Africa demonstrate that, even after \ud
apartheid, many of the oppressive power structures from colonial rule have remained in \ud
place. These structures have been augmented by increasingly dominant governing \ud
technologies of neoliberalism, which mandate that members of society regulate \ud
themselves in order to maximize their economic output, while also holding “market \ud
growth” as the dominant principle for managing populations. Neoliberalism operates \ud
through particular discourses of self and society: according to neoliberal logics in South \ud
Africa, free markets hold the promise of freedom and equality, which individual citizens \ud
can realize through practicing an entrepreneurial work ethic.\ud
In this thesis, I explore the ways that young adults in Langa, a black township of Cape \ud
Town, related to the neoliberal discourses of contemporary South Africa. Through \ud
interviews with young people and through observations of a grassroots youth \ud
organization in Langa, I asked how their aspirations – their ideas of success, their visions \ud
of themselves in the future, and the practices they were currently engaging in to realize\ud
these visions – drew upon and reacted to dominant neoliberal discourse. I argue that the \ud
respondents brought their experiences of marginalization to bear in their performance of \ud
neoliberal narratives, reformulating a set of ideas that substantiates hegemonic power \ud
relations into transgressive visions of their own actualization. Black youth in Langa \ud
created new ways of understanding the economy, the city, and the workings of \ud
governance, which centered the collective support and creative abilities of marginalized \ud
people. Through a youth organization called “Real Phandaz”, they put these \ud
understandings into radical practice within a seemingly neoliberal setting. This study, I \ud
argue, works towards an understanding of “neoliberalism from below” by exploring how\ud
a group of young people in Langa practiced new understandings of liberation from their \ud
marginalized position
Playing Strangers, Providing Care: An Ethnographic Study of Yik Yak at Swarthmore College
No full textYik Yak, a location-based anonymous posting app, has been accused of fostering\ud
overwhelmingly negative interactions and abuse. The app allows users to “play” at being \ud
strangers in their own geographically intimate community. This paper, based on research \ud
conducted at Swarthmore College, examines the ways in which interactions on Yik Yak\ud
extend beyond the negative, exploring the community’s use of anonymity and \ud
construction of support networks through field study and personal accounts of app users
Gentrification, Urban Development, and Belonging in the Mission
No full textIn much of the existing literature on gentrification, much of the focus is placed on the\ud
causes and effects of gentrification, whether they are seen as positive or negative. This \ud
thesis argues that it is equally important to consider residents’ experiences with \ud
gentrification as it affects their everyday lives in different ways depending on their \ud
personal networks and connections within the neighborhood. Building upon the work that \ud
has been done by the Anti- Eviction Mapping Project in San Francisco and drawing inspiration from the San Francisco Chronicle’s documentary A Changing Mission, my \ud
research engages with a more diverse group of residents with vary levels of connection to\ud
the Mission, assessing the ways they make sense of what gentrification means. Adopting \ud
Nancy Raquel Mirabal’s “oral history” approach, my thesis highlights the ways in which \ud
residents come to understand what the neighborhood of the Mission is about, the ways \ud
that they experience the changes in the area, and how they negotiate their own positions\ud
in the community, whatever they interpret that to be. Connecting this to existing theories \ud
of local belonging, I argue that residents’ experiences with gentrification are much more complicated than just their positionality within the gentrification debates. Change in the \ud
Mission can occur on multiple different levels and there are various dimensions to local\ud
belonging that residents struggle with to maintain a sense of place in the neighborhood
Community Engagement and Social Responsibility Semianr
No full textThis seminar links community engagement opportunities made available through offices and programs in the Bi-Co to theories of injustice, direct service, and social transformation. Through readings, documentaries, and discussions, students will explore how structural violence, interpersonal power dynamics, and personal agency influence individual behaviors and outcomes; how solidarity models of community service differ from charity models; how privilege and cultural biases shape how we see other communities. Using his/her own community work as case studies, each student will research the history, mission, and practices of the organizations as well as specific issues faced by the community; post three short response to the readings on Moodle; record and reflect in a journal on specific events, interactions or outcomes within the placement; compile a final portfolio documenting work in the community and examining its benefits and limitations for the student, the organization, and the community
Senior Seminar in Health Studies
No full textRequired culminating seminar, which integrates the three tracks of the Health Studies minor: mechanisms of disease, prevention and treatment; cultural representations of health, illness and healing; and social factors that structure risk for disease and access to healthcare. The theme for this semester’s seminar, Indigenous Health and Well-being, will be explored through assigned readings, documentaries, public health datasets, government and tribal documents, and discussions with visiting speakers. Drawing from their major disciplines, students will identify a particular issue within American Indian health, synthesize and analyze relevant literature within their discipline, and develop an original piece of work. Depending on the student’s major, possible end products include: a set of experiments and a discussion of the potential results; the design of a drug trial, complete with the correct statistical analysis; an educational curriculum or community intervention; a proposal for a monograph; or an artistic work. Students will share and critically assess their own and their fellow students’ ongoing work in the seminar so that they learn to communicate across disciplines and understand the value of and interconnectedness of different disciplinary approaches. Students will present and defend their semester-long project in a poster or oral presentation at the end of the course.\ud
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We are fortunate to have a wide array of majors, minors and concentrations represented in this first senior seminar for the Bi-Co HLTH minor. To facilitate collaboration within and across these many disciplines, the class will identify 6-8 health concerns. Three to four students will form an interest group or task force addressing one of these health concerns and each member of that group will develop an individual discipline-informed project relevant to that health concern. Oral presentations throughout the semester will be organized and delivered by these groups
Religion,Power and Politics in Latin America
No full textThis course analyzes the connections between religion, power and politics across Latin America from the sixteenth century through the recent past. Given the vast chronological and geographical scope of this class, we will have to be selective. Topics to be considered include Christianity and colonization; religious persecution in the early modern era; abolitionism and the end of slavery; the emergence of Liberation Theology and its intersection with resistance, rebellion and revolution on the popular level; and recent efforts at post conflict reconciliation and peace building. Students will have the opportunity to focus on their own concerns while gaining a thorough introduction to the current research interests of the instructor
Genome-wide search for regulators of a Vibrio parahaemolyticus type III secretion system
No full textVibrio parahaemolyticus is a foodborne bacterial pathogen that is the leading\ud
global cause of seafood-associated gastroenteritis. V. parahaemolyticus infection of humans and other mammals requires type III secretion system 2 (T3SS2), which is encoded on a pathogenicity island (VPal-7). These secretion systems translocate effector proteins from the bacterial to the host cell cytosol. T3SS2 expression is induced in response to bile, and this induction is dependent on two transcription factors, VtrA and VtrB. Here we seek to elucidate additional putative regulators of the T3SS2 expression pathway through the use of a genome-wide transposon-insertion screen and comparative genomics of several clinical and environmental isolates of V. parahaemolyticus. We reveal an expansive genetic network controlling T3SS2 with many putative regulators to biologically validate