Matching Items (96)
Description
Pathogenic Gram-negative bacteria employ a variety of molecular mechanisms to combat host defenses. Two-component regulatory systems (TCR systems) are the most ubiquitous signal transduction systems which regulate many genes required for virulence and survival of bacteria. In this study, I analyzed different TCR systems in two clinically-relevant Gram-negative bacteria, i.e., oral pathogen Porphyromonas gingivalis and enterobacterial Escherichia coli. P. gingivalis is a major causative agent of periodontal disease as well as systemic illnesses, like cardiovascular disease. A microarray study found that the putative PorY-PorX TCR system controls the secretion and maturation of virulence factors, as well as loci involved in the PorSS secretion system, which secretes proteinases, i.e., gingipains, responsible for periodontal disease. Proteomic analysis (SILAC) was used to improve the microarray data, reverse-transcription PCR to verify the proteomic data, and primer extension assay to determine the promoter regions of specific PorX regulated loci. I was able to characterize multiple genetic loci regulated by this TCR system, many of which play an essential role in hemagglutination and host-cell adhesion, and likely contribute to virulence in this bacterium. Enteric Gram-negative bacteria must withstand many host defenses such as digestive enzymes, low pH, and antimicrobial peptides (AMPs). The CpxR-CpxA TCR system of E. coli has been extensively characterized and shown to be required for protection against AMPs. Most recently, this TCR system has been shown to up-regulate the rfe-rff operon which encodes genes involved in the production of enterobacterial common antigen (ECA), and confers protection against a variety of AMPs. In this study, I utilized primer extension and DNase I footprinting to determine how CpxR regulates the ECA operon. My findings suggest that CpxR modulates transcription by directly binding to the rfe promoter. Multiple genetic and biochemical approaches were used to demonstrate that specific TCR systems contribute to regulation of virulence factors and resistance to host defenses in P. gingivalis and E. coli, respectively. Understanding these genetic circuits provides insight into strategies for pathogenesis and resistance to host defenses in Gram negative bacterial pathogens. Finally, these data provide compelling potential molecular targets for therapeutics to treat P. gingivalis and E. coli infections.
ContributorsLeonetti, Cori (Author) / Shi, Yixin (Thesis advisor) / Stout, Valerie (Committee member) / Nickerson, Cheryl (Committee member) / Sandrin, Todd (Committee member) / Arizona State University (Publisher)
Created2013
Description
The study of bacterial resistance to antimicrobial peptides (AMPs) is a significant area of interest as these peptides have the potential to be developed into alternative drug therapies to combat microbial pathogens. AMPs represent a class of host-mediated factors that function to prevent microbial infection of their host and serve as a first line of defense. To date, over 1,000 AMPs of various natures have been predicted or experimentally characterized. Their potent bactericidal activities and broad-based target repertoire make them a promising next-generation pharmaceutical therapy to combat bacterial pathogens. It is important to understand the molecular mechanisms, both genetic and physiological, that bacteria employ to circumvent the bactericidal activities of AMPs. These understandings will allow researchers to overcome challenges posed with the development of new drug therapies; as well as identify, at a fundamental level, how bacteria are able to adapt and survive within varied host environments. Here, results are presented from the first reported large scale, systematic screen in which the Keio collection of ~4,000 Escherichia coli deletion mutants were challenged against physiologically significant AMPs to identify genes required for resistance. Less than 3% of the total number of genes on the E. coli chromosome was determined to contribute to bacterial resistance to at least one AMP analyzed in the screen. Further, the screen implicated a single cellular component (enterobacterial common antigen, ECA) and a single transporter system (twin-arginine transporter, Tat) as being required for resistance to each AMP class. Using antimicrobial resistance as a tool to identify novel genetic mechanisms, subsequent analyses were able to identify a two-component system, CpxR/CpxA, as a global regulator in bacterial resistance to AMPs. Multiple previously characterized CpxR/A members, as well as members found in this study, were identified in the screen. Notably, CpxR/A was found to transcriptionally regulate the gene cluster responsible for the biosynthesis of the ECA. Thus, a novel genetic mechanism was uncovered that directly correlates with a physiologically significant cellular component that appears to globally contribute to bacterial resistance to AMPs.
ContributorsWeatherspoon-Griffin, Natasha (Author) / Shi, Yixin (Thesis advisor) / Clark-Curtiss, Josephine (Committee member) / Misra, Rajeev (Committee member) / Nickerson, Cheryl (Committee member) / Stout, Valerie (Committee member) / Arizona State University (Publisher)
Created2013
Description
Along with the number of technologies that have been introduced over a few years ago, gesture-based human-computer interactions are becoming the new phase in encompassing the creativity and abilities for users to communicate and interact with devices. Because of how the nature of defining free-space gestures influence user's preference and the length of usability of gesture-driven devices, defined low-stress and intuitive gestures for users to interact with gesture recognition systems are necessary to consider. To measure stress, a Galvanic Skin Response instrument was used as a primary indicator, which provided evidence of the relationship between stress and intuitive gestures, as well as user preferences towards certain tasks and gestures during performance. Fifteen participants engaged in creating and performing their own gestures for specified tasks that would be required during the use of free-space gesture-driven devices. The tasks include "activation of the display," scroll, page, selection, undo, and "return to main menu." They were also asked to repeat their gestures for around ten seconds each, which would give them time and further insight of how their gestures would be appropriate or not for them and any given task. Surveys were given at different time to the users: one after they had defined their gestures and another after they had repeated their gestures. In the surveys, they ranked their gestures based on comfort, intuition, and the ease of communication. Out of those user-ranked gestures, health-efficient gestures, given that the participants' rankings were based on comfort and intuition, were chosen in regards to the highest ranked gestures.
ContributorsLam, Christine (Author) / Walker, Erin (Thesis director) / Danielescu, Andreea (Committee member) / Barrett, The Honors College (Contributor) / Ira A. Fulton School of Engineering (Contributor) / School of Arts, Media and Engineering (Contributor) / Department of English (Contributor) / Computing and Informatics Program (Contributor)
Created2015-05
Description
Hepatitis C virus (HCV) is a globally prevalent infection which is a main contributor to the global burden of liver disease. Due to its ability to establish a chronic infection, and the lack of usefulness of traditional neutralizing antibody vaccine design in producing a protective immune response, a preventative vaccine has been notoriously difficult to produce. To overcome this, a vaccine using non-structural protein 3 (NS3) as a target to elicit a T cell specific immune response is thought to be a possible strategy for eliciting a protective immune response against hepatitis C infection. In this paper, a recombinant strain of measles virus (MV) that expresses HCV NS3 protein was analyzed. The replication fitness of this recombinant virus also indicates that this construct replicates at a higher rate than parental measles strain. It is also demonstrated through western blot analysis of protein expression and immunofluorescence that this recombinant virus expresses both the inserted HCV NS3 protein, as well as native measles proteins.
ContributorsWoell, Dana Marie (Author) / Reyes del Valle, Jorge (Thesis director) / Nickerson, Cheryl (Committee member) / Julik, Emily (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2015-05
Description
Lean and Green construction methodologies are prevalent in today's construction industry. Green construction implementation in buildings has progressed quickly due to the popularity and development of building rating systems, such as LEED, Green Globes, and the Living Building Challenge. Similarly, lean construction has become more popular as this philosophy often leads to efficient construction and improved owner satisfaction. Green construction is defined as using sustainable materials in the construction process to eliminate environmental degradation and ensure that material and equipment use aligns with the design intent and promotes efficient building performance. Lean construction is defined as a set of operational/systematic processes that reduce waste and eliminates defects in the project process throughout its lifecycle. This paper describes the implementation of Lean and Green construction processes to determine the trends that each methodology contributes to a project as well as how these methodologies synergize. The authors identified common elements of each methodology through semi-structured interviews with several construction industry professionals who had extensive experience with lean and green construction. Interviewees report lean and green construction philosophies are different "flavors" of the industry; however, interviewees also state if implemented together, these processes often result in a high-performance building.
ContributorsMaris, Kelsey Lynn (Co-author) / Parrish, Kristen (Co-author, Thesis director) / Olson, Patricia (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / Del E. Webb Construction (Contributor)
Created2015-05
Description
As the demand for natural resources increases with population growth, importance has been placed on environmental issues due to increasing pressure on land, water, air, and raw materials. In order to sustain the environment and natural resources, sustainable engineering and earth systems engineering and management (ESEM) is vital for future populations. The Aral Sea and the Florida Everglades are both regions that are heavily impacted by human design decisions. Comparing and analyzing the implications and outcomes of these human design decisions allows conclusions to be made regarding how earth systems engineering and management can be best accomplished. The Aral Sea, located in central Asia between Kazakhstan and Uzbekistan, is a case study of an ecosystem that has collapsed under the pressure of agricultural expansion. This has caused extensive economic, health, agricultural, and environmental impacts. The Everglades in southern Florida is a case study where the ecosystem has evolved from its original state, rather than collapsed, due to human settlement and water resource demand. In order to determine effective sustainable engineering approaches, the case studies will be evaluated using ESEM principles. These principles are used as guidance in executing better practice of sustainable engineering. When comparing the two case studies, it appears that the Everglades is an adequate representation of effective ESEM approaches, while the Aral Sea is not reflective of effective approaches. When practicing ESEM, it is critical that the principles be applied as a whole rather than individually. While the ESEM principles do not guarantee success, they offer an effective guide to dealing with the complexity and uncertainty in many of today's systems.
ContributorsRidley, Brooke Nicole (Author) / Allenby, Brad (Thesis director) / Parrish, Kristen (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12
Description
Clean water for drinking, food preparation, and bathing is essential for astronaut health and safety during long duration habitation of the International Space Station (ISS), including future missions to Mars. Despite stringent water treatment and recycling efforts on the ISS, it is impossible to completely prevent microbial contamination of onboard water supplies. In this work, we used a spaceflight analogue culture system to better understand how the microgravity environment can influence the pathogenesis-related characteristics of Burkholderia cepacia complex (Bcc), an opportunistic pathogen previously recovered from the ISS water system. The results of the present study suggest that there may be important differences in how this pathogen can respond and adapt to spaceflight and other low fluid shear environments encountered during their natural life cycles. Future studies are aimed at understanding the underlying mechanisms responsible for these phenotypes.
ContributorsKang, Bianca Younseon (Author) / Nickerson, Cheryl (Thesis director) / Barrila, Jennifer (Committee member) / Ott, Mark (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The objective for Under the Camper Shell was to build a prototype of a full living environment within the confines of a pickup truck bed and camper shell. The total volume available to work with is approximately 85ft3. This full living environment entails functioning systems for essential modern living, providing shelter and spaces for cooking, sleeping, eating, and sanitation. The project proved to be very challenging from the start. First, the livable space is extremely small, being only tall enough for one to sit up straight. The truck and camper shell were both borrowed items, so no modifications were allowed for either, e.g. drilling holes for mounting. The idea was to create a system that could be easily removed, transforming it from a camper to a utility truck. The systems developed for the living environment would be modular and transformative so to accommodate for different necessities when packing. The goal was to create a low-water system with sustainability in mind. Insulating the space was the largest challenge and the most rewarding, using body heat to warm the space and insulate from the elements. Comfort systems were made of high density foam cushions in sections to allow folding and stacking for different functions (sleeping, lounging, and sitting). Sanitation is necessary for healthy living and regular human function. A composting toilet was used for the design, lending to low-water usage and is sustainable over time. Saw dust would be necessary for its function, but upon composting, the unit will generate sufficient amounts of heat to act as a space heater. Showering serves the functions of exfoliation and ridding of bacteria, both of which bath wipes can accomplish, limiting massive volumes of water storage and waste. Storage systems were also designed for modularity. Hooks were installed the length of the bed for hanging or securing items as necessary. Some are available for hanging bags. A cabinetry rail also runs the length of the bed to allow movement of hard storage to accommodate different scenarios. The cooking method is called "sous-vide", a method of cooking food in air-tight bags submerged in hot water. The water is reusable for cooking and no dishes are necessary for serving. Overall, the prototype fulfilled its function as a full living environment with few improvements necessary for future use.
ContributorsLimsirichai, Pimwadee (Author) / Foy, Joseph (Thesis director) / Parrish, Kristen (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor) / School of Sustainability (Contributor)
Created2014-12
Description
Many student engagement studies take a holistic view of the student experience at a university setting, which includes factors both inside and outside of the classroom. However, most engagement improvements focus on activities outside of the classroom. Some research regarding improving teaching styles and activities shows an impact on engagement, but little research has investigated the impact of the built environment on student engagement. This paper explores the definition of student engagement, what environmental variables affect building occupant performance, and specifically addresses how environmental variables can impact student engagement. The authors provide a review of literature discussing these variables as well as propose a method for quantifying the impact of the built environment on students based on results of a preliminary study. Evidence of a relationship between human comfort and student engagement can provide an argument for how thoughtful building designs can improve student success and engineering education. It can further extend to industry settings where green building design can lower operating costs and improve worker satisfaction and productivity.
ContributorsDuggan, Kathleen Rose (Author) / Parrish, Kristen (Thesis director) / Khanna, Vikas (Committee member) / Beckert, Kimberly (Committee member) / Industrial, Systems (Contributor) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2014-05
Description
The paper was written for the International Group for Lean Construction Conference in July 2013 in Fortaleza, Brazil.
With the advent of sustainable building ordinances in the United States and internationally, contractors are required to deliver sustainable projects but have historically not been considered partners in developing the sustainability goals and objectives for projects. Additionally, as alternative project delivery methods gain popularity, contractors have an opportunity and—in an increasing number of cases—a requirement, to take a larger role in sustainability efforts beyond the design phase. Understanding the contractor’s self-perceived role in this industry is imperative to informing their future role in the sustainable construction industry. This paper presents data and analysis of a survey of general contractors in the Phoenix, Arizona market that asked for their opinions and viewpoints regarding sustainable construction. Respondents provided feedback about corporate profitability, growth forecast, and the perceived efficiency of the U.S Green Building Council’s LEED rating system. The survey also queried contractors about current and future work breakdown structures for sustainable project delivery as well as their underlying motives for involvement in these projects.
Academics from Arizona State University worked with local industry to develop the survey in 2012 and the survey was deployed in 2013. We sent the survey to 76 contractors and received responses from 21, representing a 27.6% response rate. Respondents include representatives from general contractors, mechanical contractors, and electrical contractors, among others. This paper presents the responses from general contractors as they typically have most contact with the owner and design teams.
With the advent of sustainable building ordinances in the United States and internationally, contractors are required to deliver sustainable projects but have historically not been considered partners in developing the sustainability goals and objectives for projects. Additionally, as alternative project delivery methods gain popularity, contractors have an opportunity and—in an increasing number of cases—a requirement, to take a larger role in sustainability efforts beyond the design phase. Understanding the contractor’s self-perceived role in this industry is imperative to informing their future role in the sustainable construction industry. This paper presents data and analysis of a survey of general contractors in the Phoenix, Arizona market that asked for their opinions and viewpoints regarding sustainable construction. Respondents provided feedback about corporate profitability, growth forecast, and the perceived efficiency of the U.S Green Building Council’s LEED rating system. The survey also queried contractors about current and future work breakdown structures for sustainable project delivery as well as their underlying motives for involvement in these projects.
Academics from Arizona State University worked with local industry to develop the survey in 2012 and the survey was deployed in 2013. We sent the survey to 76 contractors and received responses from 21, representing a 27.6% response rate. Respondents include representatives from general contractors, mechanical contractors, and electrical contractors, among others. This paper presents the responses from general contractors as they typically have most contact with the owner and design teams.
ContributorsHolloway, Skyler Brock (Author) / Parrish, Kristen (Thesis director) / Bashford, Howard (Committee member) / Meek, Jeremy (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / W. P. Carey School of Business (Contributor) / Del E. Webb Construction (Contributor)
Created2013-05