Matching Items (53)
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
Consideration of both biological and human-use dynamics in coupled social-ecological systems is essential for the success of interventions such as marine reserves. As purely human institutions, marine reserves have no direct effects on ecological systems. Consequently, the success of a marine reserve depends on managers` ability to alter human behavior in the direction and magnitude that supports reserve objectives. Further, a marine reserve is just one component in a larger coupled social-ecological system. The social, economic, political, and biological landscape all determine the social acceptability of a reserve, conflicts that arise, how the reserve interacts with existing fisheries management, accuracy of reserve monitoring, and whether the reserve is ultimately able to meet conservation and fishery enhancement goals. Just as the social-ecological landscape is critical at all stages for marine reserve, from initial establishment to maintenance, the reserve in turn interacts with biological and human use dynamics beyond its borders. Those interactions can lead to the failure of a reserve to meet management goals, or compromise management goals outside the reserve. I use a bio-economic model of a fishery in a spatially patchy environment to demonstrate how the pre-reserve fisheries management strategy determines the pattern of fishing effort displacement once the reserve is established, and discuss the social, political, and biological consequences of different patterns for the reserve and the fishery. Using a stochastic bio-economic model, I demonstrate how biological and human use connectivity can confound the accurate detection of reserve effects by violating assumptions in the quasi-experimental framework. Finally, I examine data on recreational fishing site selection to investigate changes in response to the announcement of enforcement of a marine reserve in the Gulf of California, Mexico. I generate a scale of fines that would fully or partially protect the reserve, providing a data-driven way for managers to balance biological and socio-economic goals. I suggest that natural resource managers consider human use dynamics with the same frequency, rigor, and tools as they do biological stocks.
ContributorsFujitani, Marie (Author) / Abbott, Joshua (Thesis advisor) / Fenichel, Eli (Thesis advisor) / Gerber, Leah (Committee member) / Anderies, John (Committee member) / Arizona State University (Publisher)
Created2014
Description
This paper studies the change in social diversity and interaction space from the Classic to Postclassic periods in the Mimbres Valley and East Mimbres Area. Between the Classic and Postclassic periods the Mimbres region of the American Southwest exhibits an increase in diversity of ceramic wares. Previous research suggests that increased diversity of ceramics indicates a more diverse community, which could pose challenges to local social interaction (Nelson et al. 2011). I am interested in whether the architecture of plazas, focal points of communities' social structures, change in response to the growing social diversity. To examine this, I quantify the diversity of painted ceramics at Classic and Postclassic villages as well as the extent of the enclosure of plazas. I find that there is a definite shift towards greater plaza enclosure between the Classic and Postclassic periods. I conclude this paper with a discussion of possible interpretations of this trend regarding the social reactions of Mimbres communities to the changes which reshaped the region between the Classic and Postclassic periods.
ContributorsHarkness, Rebecca Jean (Author) / Nelson, Margaret (Thesis director) / Hegmon, Michelle (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Historical, Philosophical and Religious Studies (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
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
This project created a teaching curriculum resource guide for using the popular series, The Hunger Games, in 6th-8th grade classrooms to introduce cultural issues such as child soldiers and international development to students. Studies have shown that literature can cultivate empathy and encourage youth to act. This combined with the expanding phenomenon of participatory culture and fandom activism as outlined by Henry Jenkins demonstrate the potential for youth to learn and act when given the opportunity and resources to do so. The curriculum is composed of three units: The first is a three-week reading of the books with various activities for students to really understand the narrative and source text. The second and third units address the issues of child soldiers and international development using The Hunger Games as a framework and a keystone to build connections so that these complex issues are accessible to youth. This project is a first step in the development of a curriculum that spans the full trilogy and covers a variety of current event topics.
ContributorsSimpson, Rebecca (Author) / Sivak, Henry (Thesis director) / Blasingame, James (Committee member) / Nelson, Margaret (Committee member) / Barrett, The Honors College (Contributor) / School of Politics and Global Studies (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2014-05
Description
Background: Latinos represent 40.8% of the population in Phoenix (U.S. Census Bureau Population Division, 2010). South Phoenix, also known as the South Mountain Village, defined in geographical terms as area zip codes 85040 and 85042; is a predominantly Latino community comprised of mixed citizenship status households. During the 2010 United States Census 60.3% of the population in South Phoenix identified as Latino, 25.75% of the total population was foreign born. Of the foreign born population, 88.95% were of Latin American origin (United States Census Bureau, 2007-2011 American Community Survey). Understanding how Latino immigrants perceive differences in health between their communities in country of origin and communities in the United States is largely unknown. Irrespective of political positions, understanding how Latino immigrants perceive personal health and the health of their communities is of interest to inform public policy and implement needed interventions in the
public health sphere.
Methods: Semi-structured interviews were collected from 55 adults from the South Phoenix community between November 2009 and September 2010. Interviews were digitally recorded with participant permission and transcribed. Of those collected, 48 transcribed interviews were analyzed using a codebook designed by the researcher. Percent agreement evaluated inter-rater reliability.Results: Latino immigrants in South Phoenix largely agree that health quality is heavily dependent on personal responsibility and not an intrinsic attribute of a given place. Emotional contentedness and distress, both factors of mental health, are impacted by cross-cultural differences between Latino and U.S. culture systems.
Conclusions: As people’s personal perceptions of differences in health are complex concepts influenced by personal backgrounds, culture, and beliefs, attempting to demark a side of the border as ‘healthier’ than the other using personal perceptions is overly simplified and misses central concepts. Instead, exploration of individual variables impacting health allowed this study to gain a more nuanced understanding in how people determine quality of both personal and environmental health. While Latino migrants in South Phoenix largely agree that health is based on personal responsibility and choices, many nonetheless experience higher levels of contentedness and emotional health in their country of origin.
public health sphere.
Methods: Semi-structured interviews were collected from 55 adults from the South Phoenix community between November 2009 and September 2010. Interviews were digitally recorded with participant permission and transcribed. Of those collected, 48 transcribed interviews were analyzed using a codebook designed by the researcher. Percent agreement evaluated inter-rater reliability.Results: Latino immigrants in South Phoenix largely agree that health quality is heavily dependent on personal responsibility and not an intrinsic attribute of a given place. Emotional contentedness and distress, both factors of mental health, are impacted by cross-cultural differences between Latino and U.S. culture systems.
Conclusions: As people’s personal perceptions of differences in health are complex concepts influenced by personal backgrounds, culture, and beliefs, attempting to demark a side of the border as ‘healthier’ than the other using personal perceptions is overly simplified and misses central concepts. Instead, exploration of individual variables impacting health allowed this study to gain a more nuanced understanding in how people determine quality of both personal and environmental health. While Latino migrants in South Phoenix largely agree that health is based on personal responsibility and choices, many nonetheless experience higher levels of contentedness and emotional health in their country of origin.
ContributorsGray, Laurel (Author) / Wutich, Amber (Thesis director) / Quiroga, S. Seline (Committee member) / Nelson, Margaret (Committee member) / Slade, B. Alexandra (Committee member) / Barrett, The Honors College (Contributor) / College of Liberal Arts and Sciences (Contributor)
Created2013-05
Description
The Mimbres tradition of southwestern New Mexico, underwent what can be characterized as continuity with change, a form of non-collapse transformation, from the Late Pithouse (ca. 550-1000 CE) to Classic (ca. 1000-1130 CE) period. Both transitions are characterized by large-scale shifts in housing, settlement patterns, pottery, and mortuary customs.The goal of this thesis is to evaluate changes in the intrasite and inter-site frequencies of selected nonlocal items in Mimbres burial contexts dating to the Late Pithouse and Classic periods. Because those living in the Mimbres region seem to have dramatically changed the ways in which they lived and expressed their social identities it is reasonable to assume that their mortuary use of these high-value objects might have also transformed.
ContributorsOwen, Paige Elizabeth (Author) / Nelson, Ben (Thesis director) / Nelson, Margaret (Committee member) / Russell, Will (Committee member) / Barrett, The Honors College (Contributor) / Walter Cronkite School of Journalism and Mass Communication (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2013-12
DescriptionThis paper provides an analysis of the differences in impacts made by companies that promote their sustainability efforts. A comparison of companies reveals that the ones with greater supply chain influence and larger consumer bases can make more concrete progress in terms of accomplishment for the sustainability realm.
ContributorsBeaubien, Courtney Lynn (Author) / Anderies, John (Thesis director) / Allenby, Brad (Committee member) / Janssen, Marco (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05