Matching Items (517)
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Description
Membrane proteins are very important for all living cells, being involved in respiration, photosynthesis, cellular uptake and signal transduction, amongst other vital functions. However, less than 300 unique membrane protein structures have been determined to date, often due to difficulties associated with the growth of sufficiently large and well-ordered crystals.

Membrane proteins are very important for all living cells, being involved in respiration, photosynthesis, cellular uptake and signal transduction, amongst other vital functions. However, less than 300 unique membrane protein structures have been determined to date, often due to difficulties associated with the growth of sufficiently large and well-ordered crystals. This work has been focused on showing the first proof of concept for using membrane protein nanocrystals and microcrystals for high-resolution structure determination. Upon determining that crystals of the membrane protein Photosystem I, which is the largest and most complex membrane protein crystallized to date, exist with only a hundred unit cells with sizes of less than 200 nm on an edge, work was done to develop a technique that could exploit the growth of the Photosystem I nanocrystals and microcrystals. Femtosecond X-ray protein nanocrystallography was developed for use at the first high-energy X-ray free electron laser, the LCLS at SLAC National Accelerator Laboratory, in which a liquid jet would bring fully hydrated Photosystem I nanocrystals into the interaction region of the pulsed X-ray source. Diffraction patterns were recorded from millions of individual PSI nanocrystals and data from thousands of different, randomly oriented crystallites were integrated using Monte Carlo integration of the peak intensities. The short pulses ( 70 fs) provided by the LCLS allowed the possibility to collect the diffraction data before the onset of radiation damage, exploiting the diffract-before-destroy principle. At the initial experiments at the AMO beamline using 6.9- Å wavelength, Bragg peaks were recorded to 8.5- Å resolution, and an electron-density map was determined that did not show any effects of X-ray-induced radiation damage. Recently, femtosecond X-ray protein nanocrystallography experiments were done at the CXI beamline of the LCLS using 1.3- Å wavelength, and Bragg reflections were recorded to 3- Å resolution; the data are currently being processed. Many additional techniques still need to be developed to explore the femtosecond nanocrystallography technique for experimental phasing and time-resolved X-ray crystallography experiments. The first proof-of-principle results for the femtosecond nanocrystallography technique indicate the incredible potential of the technique to offer a new route to the structure determination of membrane proteins.
ContributorsHunter, Mark (Author) / Fromme, Petra (Thesis advisor) / Wolf, George (Committee member) / Levitus, Marcia (Committee member) / Arizona State University (Publisher)
Created2011
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Description
Molybdenum (Mo) is a key trace nutrient for biological assimilation of nitrogen, either as nitrogen gas (N2) or nitrate (NO3-). Although Mo is the most abundant metal in seawater (105 nM), its concentration is low (<5 nM) in most freshwaters today, and it was scarce in the ocean before 600

Molybdenum (Mo) is a key trace nutrient for biological assimilation of nitrogen, either as nitrogen gas (N2) or nitrate (NO3-). Although Mo is the most abundant metal in seawater (105 nM), its concentration is low (<5 nM) in most freshwaters today, and it was scarce in the ocean before 600 million years ago. The use of Mo for nitrogen assimilation can be understood in terms of the changing Mo availability through time; for instance, the higher Mo content of eukaryotic vs. prokaryotic nitrate reductase may have stalled proliferation of eukaryotes in low-Mo Proterozoic oceans. Field and laboratory experiments were performed to study Mo requirements for NO3- assimilation and N2 fixation, respectively. Molybdenum-nitrate addition experiments at Castle Lake, California revealed interannual and depth variability in plankton community response, perhaps resulting from differences in species composition and/or ammonium availability. Furthermore, lake sediments were elevated in Mo compared to soils and bedrock in the watershed. Box modeling suggested that the largest source of Mo to the lake was particulate matter from the watershed. Month-long laboratory experiments with heterocystous cyanobacteria (HC) showed that <1 nM Mo led to low N2 fixation rates, while 10 nM Mo was sufficient for optimal rates. At 1500 nM Mo, freshwater HC hyperaccumulated Mo intercellularly, whereas coastal HC did not. These differences in storage capacity were likely due to the presence in freshwater HC of the small molybdate-binding protein, Mop, and its absence in coastal and marine cyanobacterial species. Expression of the mop gene was regulated by Mo availability in the freshwater HC species Nostoc sp. PCC 7120. Under low Mo (<1 nM) conditions, mop gene expression was up-regulated compared to higher Mo (150 and 3000 nM) treatments, but the subunit composition of the Mop protein changed, suggesting that Mop does not bind Mo in the same manner at <1 nM Mo that it can at higher Mo concentrations. These findings support a role for Mop as a Mo storage protein in HC and suggest that freshwater HC control Mo cellular homeostasis at the post-translational level. Mop's widespread distribution in prokaryotes lends support to the theory that it may be an ancient protein inherited from low-Mo Precambrian oceans.
ContributorsGlass, Jennifer (Author) / Anbar, Ariel D (Thesis advisor) / Shock, Everett L (Committee member) / Jones, Anne K (Committee member) / Hartnett, Hilairy E (Committee member) / Elser, James J (Committee member) / Fromme, Petra (Committee member) / Arizona State University (Publisher)
Created2011
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Description
Anti-retroviral drugs and AIDS prevention programs have helped to decrease the rate of new HIV-1 infections in some communities, however, a prophylactic vaccine is still needed to control the epidemic world-wide. Despite over two decades of research, a vaccine against HIV-1 remains elusive, although recent clinical trials have shown promising

Anti-retroviral drugs and AIDS prevention programs have helped to decrease the rate of new HIV-1 infections in some communities, however, a prophylactic vaccine is still needed to control the epidemic world-wide. Despite over two decades of research, a vaccine against HIV-1 remains elusive, although recent clinical trials have shown promising results. Recent successes have focused on highly conserved, mucosally-targeted antigens within HIV-1 such as the membrane proximal external region (MPER) of the envelope protein, gp41. MPER has been shown to play critical roles in the viral mucosal transmission, though this peptide is not immunogenic on its own. Gag is a structural protein configuring the enveloped virus particles, and has been suggested to constitute a target of the cellular immunity potentially controlling the viral load. It was hypothesized that HIV-1 enveloped virus-like particles (VLPs) consisting of Gag and a deconstructed form of gp41 comprising the MPER, transmembrane, and cytoplasmic domains (dgp41) could be expressed in plants. Plant-optimized HIV-1 genes were constructed and expressed in Nicotiana benthamiana by stable transformation, or transiently using a tobacco mosaic virus-based expression system or a combination of both. Results of biophysical, biochemical and electron microscopy characterization demonstrated that plant cells could support not only the formation of HIV-1 Gag VLPs, but also the accumulation of VLPs that incorporated dgp41. These particles were purified and utilized in mice immunization experiments. Prime-boost strategies combining systemic and mucosal priming with systemic boosting using two different vaccine candidates (VLPs and CTB-MPR - a fusion of MPER and the B-subunit of cholera toxin) were administered to BALB/c mice. Serum antibody responses against both the Gag and gp41 antigens could be elicited in mice systemically primed with VLPs and these responses could be recalled following systemic boosting with VLPs. In addition, mucosal priming with VLPs allowed for a robust boosting response against Gag and gp41 when boosted with either candidate. Functional assays of these antibodies are in progress to test the antibodies' effectiveness in neutralizing and preventing mucosal transmission of HIV-1. This immunogenicity of plant-based Gag/dgp41 VLPs represents an important milestone on the road towards a broadly-efficacious and inexpensive subunit vaccine against HIV-1.
ContributorsKessans, Sarah (Author) / Mor, Tsafrir S (Thesis advisor) / Matoba, Nobuyuki (Committee member) / Mason, Hugh (Committee member) / Hogue, Brenda (Committee member) / Fromme, Petra (Committee member) / Arizona State University (Publisher)
Created2011
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Description

This 15-week long course is designed to introduce students, specifically in Arizona, to basic sustainability and conservation principles in the context of local reptile wildlife. Throughout the course, the students work on identifying the problem, creating visions for the desired future, and finally developing a strategy to help with reptile

This 15-week long course is designed to introduce students, specifically in Arizona, to basic sustainability and conservation principles in the context of local reptile wildlife. Throughout the course, the students work on identifying the problem, creating visions for the desired future, and finally developing a strategy to help with reptile species survival in the valley. Research shows that animals in the classroom have led to improved academic success for students. Thus, through creating this course I was able to combine conservation and sustainability curriculum with real-life animals whose survival is directly being affected in the valley. My hope is that this course will help students identify a newfound passion and call to action to protect native wildlife. The more awareness and actionable knowledge which can be brought to students in Arizona about challenges to species survival the more likely we are to see a change in the future and a stronger sense of urgency for protecting wildlife. In order to accomplish these goals, the curriculum was developed to begin with basic concepts of species needs such as food and shelter and basic principles of sustainability. As the course progresses the students analyze current challenges reptile wildlife faces, like urban sprawl, and explore options to address these challenges. The course concludes with a pilot pitch where students present their solution projects to the school.

ContributorsGoethe, Emma Rae (Author) / Brundiers, Katja (Thesis director) / Bouges, Olivia (Committee member) / School of Sustainability (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Universal Basic Income is a proposed policy where the government would regularly pay all citizens in cash. The idea of a Universal Basic Income (UBI) has had a resurgence in recent years because of popular figures like Andrew Yang and Elon Musk, but its history and potential implications go dee

Universal Basic Income is a proposed policy where the government would regularly pay all citizens in cash. The idea of a Universal Basic Income (UBI) has had a resurgence in recent years because of popular figures like Andrew Yang and Elon Musk, but its history and potential implications go deep into the structure of human society. This thesis delves into how a basic income would transform social concepts of work and disrupt the personal economic model. With the bargaining power and freedom granted by a basic income, workers would find themselves in a position of work freedom and choice that has never existed in human history. With new freedom to do as they wish, the place of work in people’s lives needs to be reimagined as a source of fulfillment instead of an unlikeable but necessary part of everyday life. Workers will be given the choice to leave unfair or unfulfilling work and decide for themselves how they want to contribute within society. From increasing mental and economic well-being for most Americans to serving as a response to unemployment trends in the automated future, to encouraging greater business innovation, there are myriad ways in which basic incomes have the potential to benefit society. Framed by Martin Luther King Jr. and Franklin Delano Roosevelt as the only policy capable of abolishing poverty forever, Universal Basic income will be an important feature of transformative innovative policy advocacy until it is adopted by a major world government at which point the effects in practice will become clear.

ContributorsSimm, Michael Anthony (Author) / Soares, Rebecca (Thesis director) / Voorhees, Matthew (Committee member) / School of Sustainability (Contributor) / School of Politics and Global Studies (Contributor) / School for the Future of Innovation in Society (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

Globally, the incidental capture of non-target species in fisheries (bycatch) has been linked to declines of ecologically, economically, and culturally important marine species. Gillnet fisheries have especially high bycatch due to their non-selective nature, necessitating the development of new bycatch reduction technologies (BRTs). Net illumination is an emerging BRT that

Globally, the incidental capture of non-target species in fisheries (bycatch) has been linked to declines of ecologically, economically, and culturally important marine species. Gillnet fisheries have especially high bycatch due to their non-selective nature, necessitating the development of new bycatch reduction technologies (BRTs). Net illumination is an emerging BRT that has shown promise in reducing bycatch of marine megafauna, including sea turtles, cetaceans, and seabirds. However, little research has been conducted to understand the effects of net illumination on fish assemblages, including bony fish and elasmobranchs (i.e. sharks, rays, and skates). Here, I assessed a 7-year dataset of paired net illumination trials using four different types of light (green LEDs, green chemical glowsticks, ultraviolet (UV) lights, and orange lights) to examine the effects of net illumination on fish catch and bycatch in a gillnet fishery at Baja California Sur, Mexico. Analysis revealed no significant effect on bony fish target catch or bycatch for any light type. There was a significant decrease in elasmobranch bycatch using UV and orange lights, with orange lights showing the most promise for decreasing elasmobranch bycatch, resulting in a 50% reduction in bycatch rates. Analysis of the effects of net illumination on elasmobranch target catch was limited due to insufficient data. These results indicate that the illumination of gillnets may offer a practical solution for reducing fish bycatch while maintaining target catch. More research should be conducted to understand the effects of net illumination in different fisheries, how net illumination affects fisher profit and efficiency, and how net illumination affects fish behavior. Further optimization of net illumination is also necessary before the technology can be recommended on a broader scale.

ContributorsBurgher, Kayla Marie (Author) / Senko, Jesse (Thesis director) / Throop, Heather (Committee member) / School of Life Sciences (Contributor) / School of Sustainability (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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As climate change continues to escalate natural hazards around the globe, certain communities feel the impacts of these disasters more so than others. After Hurricane Maria devastated communities in 2017, Puerto Rico struggled to respond to the needs of its citizens, particularly those in rural areas. Many of the regions

As climate change continues to escalate natural hazards around the globe, certain communities feel the impacts of these disasters more so than others. After Hurricane Maria devastated communities in 2017, Puerto Rico struggled to respond to the needs of its citizens, particularly those in rural areas. Many of the regions affected did not have resilient community structures in place to be able to withstand the systemic ripple effects of the hurricane. However, various community endeavors have developed post-Hurricane Maria to foster community collaboration and resiliency, including the development of agricultural tourism, otherwise known as agritourism. <br/>Although agritourism has begun to develop in rural regions of Puerto Rico, including the municipalities of Utuado, Ciales, Florida, and Jayuya, a systems-understanding is lacking of the current agritourism situation in the region and its related capacities, limitations, and opportunities of agritourism. To address this gap, a spatially explicit understanding and map of the underlying tourism infrastructure is needed to support the development of sustainable agritourism in Utuado, Jayuya, Ciales, and Florida municipalities in Puerto Rico. <br/>This report spatially represents the current state of tourism opportunities in the region as a result of asking “What are the spatial networks of gastronomy, accommodations, farms, and attractions that support the development of agritourism in Utuado, Jayuya, Ciales and Florida municipalities in Puerto Rico?” Three steps lead to the spatial representation starting with developing a comprehensive inventory. Second, we visualize the spatial map through Google Maps. Lastly, we explore the larger context of the report through an ArcGIS Storymap. The inventory will help with better understanding the number and variety of tourism resources available. The spatial visualization will help with understanding the distribution of resources and explore potential connections between resources and what relationships could be fostered in the future. Lastly, the ArcGIS Storymap will serve as a framework for outlining the future development of the SARE project. Overall, this report outlines the spatial maps of tourism resources and provides a tool to be used by community partners, tourists, and project partners.

ContributorsCretors, Kasey Ann (Author) / Brundiers, Katja (Thesis director) / Holladay, Patrick (Committee member) / Lazaro, Pablo Mendez (Committee member) / School of International Letters and Cultures (Contributor) / School of Sustainability (Contributor) / Division of Teacher Preparation (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description

Food insecure populations suffer from the ability to access affordable and nutritious foods as a result of financial and transportation needs. Often these populations are concentrated in areas referenced as food deserts. A food desert is an area that does not have a supermarket or large grocery store within a

Food insecure populations suffer from the ability to access affordable and nutritious foods as a result of financial and transportation needs. Often these populations are concentrated in areas referenced as food deserts. A food desert is an area that does not have a supermarket or large grocery store within a mile and often is saturated with small non-traditional food stores and fast- food establishments. In this study, 21 food deserts along Grand Avenue in Downtown Phoenix were analyzed to better understand their access to food, population statistics and barriers to being food secure. The research question analyzed is the impact food insecurity has on communities in Phoenix, Arizona. The findings are presented in the form of a research paper, as well as 15 black and white film photographs accompanied by descriptions. There is primary qualitative data presented through photographs and observations, as well as secondary quantitative data analyzed from Census data. The food deserts studied consist of communities that are low-income and majority minority with little to no access to nutritious food in their area. The economics of food insecurity and grocery stores, racial discrimination, access to transportation, impacts on health and education and the sustainability of food deserts are all aspects of food insecurity discussed in the research. Possible solutions such as community gardens and subsidized grocery stores are also presented. The study revealed that food insecurity has several negative impacts on the affected populations and communities and disproportionately impacts low-income and minority communities.

ContributorsHollinshead, Samantha Nadine (Author) / Liao, Chuan Liao (Thesis director) / Bavousett, Brigitte Bavousett (Committee member) / School of Sustainability (Contributor) / School of Social Transformation (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Bioluminescent algae has long fascinated humans as a beautiful natural phenomenon. This creative project uses bioluminescent algae to push the limit of biomimicry, using the algae not as a model but as a technology. Through experimentation with algae samples and industrial design, two potential applications of bioluminescent algae as a

Bioluminescent algae has long fascinated humans as a beautiful natural phenomenon. This creative project uses bioluminescent algae to push the limit of biomimicry, using the algae not as a model but as a technology. Through experimentation with algae samples and industrial design, two potential applications of bioluminescent algae as a sustainable lighting technology were generated. One design focuses on indoor, private lighting, while the other focuses on outdoor, public lighting. Both outcomes attempt to solve problems generated by nighttime lighting including light pollution, wasted electricity usage, and negative impacts on human and environmental health while retaining the benefits of safety and convenience.

ContributorsFernald, Isabel (Author) / Shin, Dosun (Thesis director) / Feil, Magnus (Committee member) / The Design School (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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We analyzed multiple different models that can be utilized when measuring effects effects of fire and fire behavior in a forest ecosystem. In the thesis we focused on exploring ordinary differential equations, stochastic models, and partial differential equations

ContributorsVo, Sabrina (Author) / Jones, Donald (Thesis director) / Parker, Nathan (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05