Matching Items (164)
Description
A notable feature of advanced eusocial insect groups is a division of labor within the sterile worker caste. However, the physiological aspects underlying the differentiation of behavioral phenotypes are poorly understood in one of the most successful social taxa, the ants. By starting to understand the foundations on which social behaviors are built, it also becomes possible to better evaluate hypothetical explanations regarding the mechanisms behind the evolution of insect eusociality, such as the argument that the reproductive regulatory infrastructure of solitary ancestors was co-opted and modified to produce distinct castes. This dissertation provides new information regarding the internal factors that could underlie the division of labor observed in both founding queens and workers of Pogonomyrmex californicus ants, and shows that changes in task performance are correlated with differences in reproductive physiology in both castes. In queens and workers, foraging behavior is linked to elevated levels of the reproductively-associated juvenile hormone (JH), and, in workers, this behavioral change is accompanied by depressed levels of ecdysteroid hormones. In both castes, the transition to foraging is also associated with reduced ovarian activity. Further investigation shows that queens remain behaviorally plastic, even after worker emergence, but the association between JH and behavioral bias remains the same, suggesting that this hormone is an important component of behavioral development in these ants. In addition to these reproductive factors, treatment with an inhibitor of the nutrient-sensing pathway Target of Rapamycin (TOR) also causes queens to become biased towards foraging, suggesting an additional sensory component that could play an important role in division of labor. Overall, this work provides novel identification of the possible regulators behind ant division of labor, and suggests how reproductive physiology could play an important role in the evolution and regulation of non-reproductive social behaviors.
ContributorsDolezal, Adam G (Author) / Amdam, Gro V (Thesis advisor) / Brent, Colin S. (Committee member) / Gadau, Juergen (Committee member) / Hoelldobler, Bert (Committee member) / Liebig, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
While exercising mammalian muscle increasingly relies on carbohydrates for fuel as aerobic exercise intensity rises above the moderate range, flying birds are extraordinary endurance athletes and fuel flight, a moderate-high intensity exercise, almost exclusively with lipid. In addition, Aves have long lifespans compared to weight-matched mammals. As skeletal muscle mitochondria account for the majority of oxygen consumption during aerobic exercise, the primary goal was to investigate differences in isolated muscle mitochondria between these species and to examine to what extent factors intrinsic to mitochondria may account for the behavior observed in the intact tissue and whole organism. First, maximal enzyme activities were assessed in sparrow and rat mitochondria. Citrate synthase and aspartate aminotransferase activity were higher in sparrow compared to rat mitochondria, while glutamate dehydrogenase activity was lower. Sparrow mitochondrial NAD-linked isocitrate dehydrogenase activity was dependent on phosphate, unlike the mammalian enzyme. Next, the rate of oxygen consumption (JO), electron transport chain (ETC) activity, and reactive oxygen species (ROS) production were assessed in intact mitochondria. Maximal rates of fat oxidation were lower than for carbohydrate in rat but not sparrow mitochondria. ETC activity was higher in sparrows, but no differences were found in ROS production between species. Finally, fuel selection and control of respiration at three rates between rest and maximum were assessed. Mitochondrial fuel oxidation and selection mirrored that of the whole body; in rat mitochondria the reliance on carbohydrate increased as the rate of oxygen consumption increased, whereas fat dominated under all conditions in the sparrow. These data indicate fuel selection, at least in part, can be modulated at the level of the mitochondrial matrix when multiple substrates are present at saturating levels. As an increase in matrix oxidation-reduction potential has been linked to a suppression of fat oxidation and high ROS production, the high ETC activity relative to dehydrogenase activity in avian compared to mammalian mitochondria may result in lower matrix oxidation-reduction potential, allowing fatty acid oxidation to proceed while also resulting in low ROS production in vivo.
ContributorsKuzmiak, Sarah (Author) / Willis, Wayne T (Thesis advisor) / Mandarino, Lawrence (Committee member) / Sweazea, Karen (Committee member) / Harrison, Jon (Committee member) / Gadau, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
Recombinant protein expression is essential to biotechnology and molecular medicine, but facile methods for obtaining significant quantities of folded and functional protein in mammalian cell culture have been lacking. Here I describe a novel 37-nucleotide in vitro selected sequence that promotes unusually high transgene expression in a vaccinia driven cytoplasmic expression system. Vectors carrying this sequence in a monocistronic reporter plasmid produce >1,000-fold more protein than equivalent vectors with conventional vaccinia promoters. Initial mechanistic studies indicate that high protein expression results from dual activity that impacts both transcription and translation. I suggest that this motif represents a powerful new tool in vaccinia-based protein expression and vaccine development technology.
ContributorsFlores, Julia Anne (Author) / Chaput, John C (Thesis advisor) / Jacobs, Bertram (Committee member) / LaBaer, Joshua (Committee member) / Arizona State University (Publisher)
Created2012
Description
Here I present a phylogeographic study of at least six reproductively isolated lineages of harvester ants within the Pogonomyrmex barbatus and P. rugosus species group. The genetic and geographic relationships within this clade are complex: four of the identified lineages are divided into two pairs, and each pair has evolved under a mutualistic system that necessitates sympatry. These paired lineages are dependent upon one another because interlineage matings within each pair are the sole source of hybrid F1 workers; these workers build and sustain the colonies, facilitating the production of the reproductive caste, which results solely from intralineage fertilizations. This system of genetic caste determination (GCD) maintains genetic isolation among these closely related lineages, while simultaneously requiring co-expansion and emigration as their distributions have changed over time. Previous studies have also demonstrated that three of the four lineages displaying this unique genetic caste determination phenotype are of hybrid origin. Thus, reconstructing the phylogenetic and geographic history of this group allows us to evaluate past insights and plan future inquiries in a more complete historical biogeographic context. Using mitochondrial DNA sequences sampled across most of the morphospecies' ranges in the U.S. and Mexico, I employed several methods of phylogenetic and DNA sequence analysis, along with comparisons to geological, biogeographic, and phylogeographic studies throughout the sampled regions. These analyses on Pogonomyrmex harvester ants reveal a complex pattern of vicariance and dispersal that is largely concordant with models of late Miocene, Pliocene, and Pleistocene range shifts among various arid-adapted taxa in North America.
ContributorsMott, Brendon (Author) / Gadau, Juergen (Thesis advisor) / Fewell, Jennifer (Committee member) / Anderson, Kirk (Committee member) / Arizona State University (Publisher)
Created2012
Description
In social insect colonies, as with individual animals, the rates of biological processes scale with body size. The remarkable explanatory power of metabolic allometry in ecology and evolutionary biology derives from the great diversity of life exhibiting a nonlinear scaling pattern in which metabolic rates are not proportional to mass, but rather exhibit a hypometric relationship with body size. While one theory suggests that the supply of energy is a major physiological constraint, an alternative theory is that the demand for energy is regulated by behavior. The central hypothesis of this dissertation research is that increases in colony size reduce the proportion of individuals actively engaged in colony labor with consequences for energetic scaling at the whole-colony level of biological organization. A combination of methods from comparative physiology and animal behavior were developed to investigate scaling relationships in laboratory-reared colonies of the seed-harvester ant, Pogonomyrmex californicus. To determine metabolic rates, flow-through respirometry made it possible to directly measure the carbon dioxide production and oxygen consumption of whole colonies. By recording video of colony behavior, for which ants were individually paint-marked for identification, it was possible to reconstruct the communication networks through which information is transmitted throughout the colony. Whole colonies of P. californicus were found to exhibit a robust hypometric allometry in which mass-specific metabolic rates decrease with increasing colony size. The distribution of walking speeds also scaled with colony size so that larger colonies were composed of relatively more inactive ants than smaller colonies. If colonies were broken into random collections of workers, metabolic rates scaled isometrically, but when entire colonies were reduced in size while retaining functionality (queens, juveniles, workers), they continued to exhibit a metabolic hypometry. The communication networks in P. californicus colonies contain a high frequency of feed-forward interaction patterns consistent with those of complex regulatory systems. Furthermore, the scaling of these communication pathways with size is a plausible mechanism for the regulation of whole-colony metabolic scaling. The continued development of a network theory approach to integrating behavior and metabolism will reveal insights into the evolution of collective animal behavior, ecological dynamics, and social cohesion.
ContributorsWaters, James S., 1983- (Author) / Harrison, Jon F. (Thesis advisor) / Quinlan, Michael C. (Committee member) / Pratt, Stephen C. (Committee member) / Fewell, Jennifer H. (Committee member) / Gadau, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
I travelled and worked in international fisheries policy for 7 months in preparation for this thesis. During this time I completed one internship in Rome, Italy with the Food and Agriculture Organization of the United Nations (UNFAO) and another internship on the island of Pohnpei with the Secretariat of the Western and Central Pacific Fisheries Commission (WCPFC). From these experiences, I selected the subject of this thesis. My thesis analyzes the management system for South Pacific albacore tuna, the source stock for brands like "Chicken of the Sea" and "Starkist". South Pacific albacore tuna pass through international waters and the waters of several Pacific Island countries and territories, necessitating States to cooperate and coordinate to sustain the future viability of the stock. A case study for transboundary natural resource management, I discuss the institutional complexity that arises from managing such a resource. I use common-pool resource (CPR) theory to describe this complexity, which frames natural resource management as a collective-action problem among resource users. I first conceptualize the management system as having multiple institutional scales and multiple levels of organization. Then, employing Ostrom's 8 design principles for successful CPR management, I conduct a multi-institution analysis of the international, regional, and subregional institutions that participate in the management system. Finally, I also conduct a cross-institution analysis by examining the interactions between these institutions. I find that significant space for theoretical development exists in CPR theory for understanding complex management systems for transboundary natural resources. Furthermore, I find that interactions between institutions create linkages that could be retooled to improve the performance of the South Pacific albacore tuna management system.
ContributorsAbolhassani, Angela Maryam (Author) / Abbott, Kenneth (Thesis director) / Schoon, Michael (Committee member) / Barrett, The Honors College (Contributor) / School of Politics and Global Studies (Contributor) / School of Life Sciences (Contributor) / Department of English (Contributor)
Created2015-05
Description
This paper explores two areas of study: Colony Collapse Disorder and urban apiculture--the practice of keeping bees in urban areas. Additionally, this paper discusses the ways in which Colony Collapse Disorder has encouraged an increase in urban beekeeping, and the possible role of urban apiculture as a means of combatting the negative effects of Colony Collapse Disorder. The symptoms, history, and possible causes of Colony Collapse Disorder are presented, as well as the important role that honey bees play in human agriculture. Following the discussion of Colony Collapse Disorder is a description of my urban beekeeping apprenticeship at Desert Marigold School where I kept bees, researched various hives, attended a beekeeping workshop in Tucson, and eventually built a hive and established a colony with my mentor. This paper includes a guide to beekeeping basics, as well as a guide to starting a hive based upon the lessons learned during my apprenticeship.
ContributorsRomero, Madelyn Rattan (Author) / Schoon, Michael (Thesis director) / Silcox, Holly (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / School of Geographical Sciences and Urban Planning (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
South Mountain is the largest municipal park in the nation. It is a bundled amenity, providing a series of linked services to the surrounding communities. A dataset of 19,209 homes in 155 neighborhoods within three miles of the park was utilized in order to complete a hedonic estimation for two nearby urban villages, Ahwatukee Foothills and South Mountain Village. Measures of access include proximity to the park, trailhead access, and adjacency to the park. Two regressions were estimated, the first including lot characteristics and subdivision fixed effects and the second using the coefficients for each subdivision as the dependent variable. These estimates describe how the location of a house in a subdivision contributes to its conditional mean price. As a result they offer a direct basis for capturing amenities measured at the neighborhood scale on home values. Park proximity, trailhead access and adjacency were found to significantly influence the price of homes at the 5% confidence level in Ahwatukee, but not in South Mountain Village. The results of this study can be applied to issues of environmental justice and park access in determining which areas and attributes of the park are associated with a high premium. Though South Mountain was preserved some time ago, development and future preservation in the City of Phoenix can be informed by such studies.
ContributorsRamakrishna, Saritha Kambhampati (Author) / Abbott, Joshua (Thesis director) / Smith, V. Kerry (Committee member) / Schoon, Michael (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / Economics Program in CLAS (Contributor) / Department of English (Contributor)
Created2015-05
Hiking and Hegemony: Destabilizing the nature/culture and gender binaries through outdoor recreation
Description
This paper explores the contested relationships between nature, culture, and gender. In order to analyze these relationships, we look specifically at outdoor recreation. Furthermore, we employ poststructuralist feminist theory in order to produce three frameworks; the first of which is titled Mother Nature’s Promiscuous Past. Rooted in Old World and colonial values, this framework illustrates the flawed feminization of nature by masculinity, and its subsequent extortion of anything related to femininity — including women and nature itself. This belief barred women from nature, resulting in a lack of access for women to outdoor recreation.
Our second framework, titled The Pleasurable Potential of Outdoor Recreation, cites second-wave feminism as a catalyst for women’s participation in wilderness exploration and outdoor recreation. The work of radical feminists and the women’s liberation movement in 1960s and 1970s empowered women at home, in the workplace, and eventually, in the outdoors; women reclaimed their wilderness, yet they continued to employ Framework One’s feminization of nature. Ecofeminsim brought together nature and women, seeking to bring justice to two groups wronged by the same entity: masculinity. In this context, outdoor recreation is empowering for women.
Despite the potential of Framework Two to reinscribe and better the experiences of women in outdoor recreation, we argue that both Frameworks One and Two perpetuate the gender binary and the nature/culture binary, because they are based upon the notion that women are in fact fundamentally different and separate from men, the notion that nature is an entity separate from culture, or human society, as well as the notion that nature is in fact a feminine entity.
Our third framework, Deer Pay No Mind to Your Genitals, engages poststructuralism, asserting that outdoor recreation and activities that occur in nature can serve to destabilize and deconstruct notions of the gender binary. However, we argue that care must be exercised during this process as not to perpetuate the problematic nature/culture binary, a phenomenon that is unproductive in terms of both sustainability and gender liberation. Outdoor recreation has been used by many as a tool to deconstruct numerous societal constraints, including the gender binary; this, however, continues to attribute escapist and isolationist qualities toward nature, and therefore perpetuating the nature/culture divide. Ultimately, we argue outdoor recreation can and should be used as a tool deconstruct the gender binary, however needs to account for the fact that if nature is helping to construct elements of culture, then the two cannot be separate.
Our second framework, titled The Pleasurable Potential of Outdoor Recreation, cites second-wave feminism as a catalyst for women’s participation in wilderness exploration and outdoor recreation. The work of radical feminists and the women’s liberation movement in 1960s and 1970s empowered women at home, in the workplace, and eventually, in the outdoors; women reclaimed their wilderness, yet they continued to employ Framework One’s feminization of nature. Ecofeminsim brought together nature and women, seeking to bring justice to two groups wronged by the same entity: masculinity. In this context, outdoor recreation is empowering for women.
Despite the potential of Framework Two to reinscribe and better the experiences of women in outdoor recreation, we argue that both Frameworks One and Two perpetuate the gender binary and the nature/culture binary, because they are based upon the notion that women are in fact fundamentally different and separate from men, the notion that nature is an entity separate from culture, or human society, as well as the notion that nature is in fact a feminine entity.
Our third framework, Deer Pay No Mind to Your Genitals, engages poststructuralism, asserting that outdoor recreation and activities that occur in nature can serve to destabilize and deconstruct notions of the gender binary. However, we argue that care must be exercised during this process as not to perpetuate the problematic nature/culture binary, a phenomenon that is unproductive in terms of both sustainability and gender liberation. Outdoor recreation has been used by many as a tool to deconstruct numerous societal constraints, including the gender binary; this, however, continues to attribute escapist and isolationist qualities toward nature, and therefore perpetuating the nature/culture divide. Ultimately, we argue outdoor recreation can and should be used as a tool deconstruct the gender binary, however needs to account for the fact that if nature is helping to construct elements of culture, then the two cannot be separate.
ContributorsPolick-Kirkpatrick, Kaelyn (Co-author) / Downing, Haley Marie (Co-author) / Dove-Viebahn, Aviva (Thesis director) / Schoon, Michael (Committee member) / School of Sustainability (Contributor) / School of Social Transformation (Contributor) / Economics Program in CLAS (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05