Matching Items (86)
Description
The goal of this project was to design and create a genetic construct that would allow for <br/>tumor growth to be induced in the center of the wing imaginal disc of Drosophila larvae, the <br/>R85E08 domain, using a heat shock. The resulting transgene would be combined with other <br/>transgenes in a single fly that would allow for simultaneous expression of the oncogene and, in <br/>the surrounding cells, other genes of interest. This system would help establish Drosophila as a <br/>more versatile and reliable model organism for cancer research. Furthermore, pilot studies were <br/>performed, using elements of the final proposed system, to determine if tumor growth is possible <br/>in the center of the disc, which oncogene produces the best results, and if oncogene expression <br/>induced later in development causes tumor growth. Three different candidate genes were <br/>investigated: RasV12, PvrACT, and Avli.
ContributorsSt Peter, John Daniel (Author) / Harris, Rob (Thesis director) / Varsani, Arvind (Committee member) / School of Molecular Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Land management practices such as domestic animal grazing can alter plant communities via changes in soil structure and chemistry, species composition, and plant nutrient content. These changes can affect the abundance and quality of plants consumed by insect herbivores with consequent changes in population dynamics. These population changes can translate to massive crop damage and pest control costs. My dissertation focused on Oedaleus asiaticus, a dominant Asian locust, and had three main objectives. First, I identified morphological, physiological, and behavioral characteristics of the migratory ("brown") and non-migratory ("green") phenotypes. I found that brown morphs had longer wings, larger thoraxes and higher metabolic rates compared to green morphs, suggesting that developmental plasticity allows greater migratory capacity in the brown morph of this locust. Second, I tested the hypothesis of a causal link between livestock overgrazing and an increase in migratory swarms of O. asiaticus. Current paradigms generally assume that increased plant nitrogen (N) should enhance herbivore performance by relieving protein-limitation, increasing herbivorous insect populations. I showed, in contrast to this scenario, that host plant N-enrichment and high protein artificial diets decreased the size and viability of O. asiaticus. Plant N content was lowest and locust abundance highest in heavily livestock-grazed fields where soils were N-depleted, likely due to enhanced erosion and leaching. These results suggest that heavy livestock grazing promotes outbreaks of this locust by reducing plant protein content. Third, I tested for the influence of dietary imbalance, in conjunction with high population density, on migratory plasticity. While high population density has clearly been shown to induce the migratory morph in several locusts, the effect of diet has been unclear. I found that locusts reared at high population density and fed unfertilized plants (i.e. high quality plants for O. asiaticus) had the greatest migratory capacity, and maintained a high percent of brown locusts. These results did not support the hypothesis that poor-quality resources increased expression of migratory phenotypes. This highlights a need to develop new theoretical frameworks for predicting how environmental factors will regulate migratory plasticity in locusts and perhaps other insects.
ContributorsCease, Arianne (Author) / Harrison, Jon (Thesis advisor) / Elser, James (Thesis advisor) / DeNardo, Dale (Committee member) / Quinlan, Michael (Committee member) / Sabo, John (Committee member) / Arizona State University (Publisher)
Created2012
Description
Conditions during development can shape the expression of traits at adulthood, a phenomenon called developmental plasticity. In this context, factors such as nutrition or health state during development can affect current and subsequent physiology, body size, brain structure, ornamentation, and behavior. However, many of the links between developmental and adult phenotype are poorly understood. I performed a series of experiments using a common molecular currency - carotenoid pigments - to track somatic and reproductive investments through development and into adulthood. Carotenoids are red, orange, or yellow pigments that: (a) animals must acquire from their diets, (b) can be physiologically beneficial, acting as antioxidants or immunostimulants, and (c) color the sexually attractive features (e.g., feathers, scales) of many animals. I studied how carotenoid nutrition and immune challenges during ontogeny impacted ornamental coloration and immune function of adult male mallard ducks (Anas platyrhynchos). Male mallards use carotenoids to pigment their yellow beak, and males with more beaks that are more yellow are preferred as mates, have increased immune function, and have higher quality sperm. In my dissertation work, I established a natural context for the role that carotenoids and body condition play in the formation of the adult phenotype and examined how early-life experiences, including immune challenges and dietary access to carotenoids, affect adult immune function and ornamental coloration. Evidence from mallard ducklings in the field showed that variation in circulating carotenoid levels at hatch are likely driven by maternal allocation of carotenoids, but that carotenoid physiology shifts during the subsequent few weeks to reflect individual foraging habits. In the lab, adult beak color expression and immune function were more tightly correlated with body condition during growth than body condition during subsequent stages of development or adulthood. Immune challenges during development affected adult immune function and interacted with carotenoid physiology during adulthood, but did not affect adult beak coloration. Dietary access to carotenoids during development, but not adulthood, also affected adult immune function. Taken together, these results highlight the importance of the developmental stage in shaping certain survival-related traits (i.e., immune function), and lead to further questions regarding the development of ornamental traits.
ContributorsButler, Michael (Author) / McGraw, Kevin J. (Thesis advisor) / Chang, Yung (Committee member) / Deviche, Pierre (Committee member) / DeNardo, Dale (Committee member) / Rutowski, Ronald (Committee member) / Arizona State University (Publisher)
Created2012
Description
Parental care provides many benefits to offspring. One widely realized benefit is enhanced regulation of offspring's thermal environment. The developmental thermal environment during development can be optimized behaviorally through nest site selection and brooding, and it can be further enhanced by physiological heat production. In fact, enhancement of the developmental thermal environment has been proposed as the initial driving force for the evolution of endothermy in bird and mammals. I used pythons (Squamata: Pythonidae) to expand existing knowledge of behavioral and physiological parental tactics used to regulate offspring thermal environment. I first demonstrated that brooding behavior in the Children's python (Antaresia childreni) is largely driven by internal mechanisms, similar to solitary birds, suggesting that the early evolution of the parent-offspring association was probably hormonally driven. Two species of python are known to be facultatively thermogenic (i.e., are endothermic during reproduction). I expand current knowledge of thermogenesis in Burmese pythons (Python molurus) by demonstrating that females use their own body temperature to modulate thermogenesis. Although pythons are commonly cited as thermogenic, the actual extent of thermogenesis within the family Pythonidae is unknown. Thus, I assessed the thermogenic capability of five previously unstudied species of python to aid in understanding phylogenetic, morphological, and distributional influences on thermogenesis in pythons. Results suggest that facultative thermogenesis is likely rare among pythons. To understand why it is rare, I used an artificial model to demonstrate that energetic costs to the female likely outweigh thermal benefits to the clutch in species that do not inhabit cooler latitudes or lack large energy reserves. In combination with other studies, these results show that facultative thermogenesis during brooding in pythons likely requires particular ecological and physiological factors for its evolution.
ContributorsBrashears, Jake (Author) / DeNardo, Dale (Thesis advisor) / Harrison, Jon (Committee member) / Deviche, Pierre (Committee member) / McGraw, Kevin (Committee member) / Smith, Andrew (Committee member) / Arizona State University (Publisher)
Created2012
Description
One of the largest problems facing modern medicine is drug resistance. Many classes of drugs can be rendered ineffective if their target is able to acquire beneficial mutations. While this is an excellent showcase of the power of evolution, it necessitates the development of increasingly stronger drugs to combat resistant pathogens. Not only is this strategy costly and time consuming, it is also unsustainable. To contend with this problem, many multi-drug treatment strategies are being explored. Previous studies have shown that resistance to some drug combinations is not possible, for example, resistance to a common antifungal drug, fluconazole, seems impossible in the presence of radicicol. We believe that in order to understand the viability of multi-drug strategies in combating drug resistance, we must understand the full spectrum of resistance mutations that an organism can develop, not just the most common ones. It is possible that rare mutations exist that are resistant to both drugs. Knowing the frequency of such mutations is important for making predictions about how problematic they will be when multi-drug strategies are used to treat human disease. This experiment aims to expand on previous research on the evolution of drug resistance in S. cerevisiae by using molecular barcodes to track ~100,000 evolving lineages simultaneously. The barcoded cells were evolved with serial transfers for seven weeks (200 generations) in three concentrations of the antifungal Fluconazole, three concentrations of the Hsp90 inhibitor Radicicol, and in four combinations of Fluconazole and Radicicol. Sequencing data was used to track barcode frequencies over the course of the evolution, allowing us to observe resistant lineages as they rise and quantify differences in resistance evolution across the different conditions. We were able to successfully observe over 100,000 replicates simultaneously, revealing many adaptive lineages in all conditions. Our results also show clear differences across drug concentrations and combinations, with the highest drug concentrations exhibiting distinct behaviors.
ContributorsApodaca, Samuel (Author) / Geiler-Samerotte, Kerry (Thesis director) / Schmidlin, Kara (Committee member) / Huijben, Silvie (Committee member) / School of Life Sciences (Contributor) / School of Molecular Sciences (Contributor) / School of Politics and Global Studies (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
An organism's ability to maintain optimal body temperature is extremely important for sustaining physiological and behavioral processes necessary for survival. However, like other physiological systems, thermobiology can be influenced by the availability of resources. Water is a vital resource that has profound implications on many aspects of biological function, including thermoregulatory pathways. However, water availability has a tendency fluctuate within any given ecosystem. While several studies have investigated the influence of water availability on a range of thermoregulatory pathways, very little attention has been given to its influence on Voluntary Maximum Temperature (VMT). We investigated the effects of dehydration on Voluntary Maximum Temperature in a captive population of Gila monsters (Heloderma suspectum). Gila monsters are large-bodied, desert dwelling lizards that experience periods of seasonal dehydration. Additionally, the effects of dehydration on their physiology and behavior have been extensively studied. We hypothesized that dehydration would reduce VMT. As expected, there was a significant decrease in exit temperature as blood osmolality increased. This is presumed to be in an effort to decrease water loss. Adaptations that allow desert dwelling organisms to conserve water are highly advantageous due to seasonal water constraints. Our findings offer insight on how the behavior of these organisms may change in response to changes in climate.
ContributorsHartson, Callie Elizabeth (Author) / DeNardo, Dale (Thesis director) / Angilletta, Michael (Committee member) / Camacho, Agus (Committee member) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Objective: To explore the dimensions of the human animal bond and provide a community needs assessment to inform the community stake holders such as the Arizona Humane Society and Nina Mason Pulliam Charitable Trust Foundation how many animals are in need of veterinary services within the homeless population of Phoenix, Arizona. In addition to this, pets of the homeless individuals will be able to gain access to veterinary services for eight consecutive weeks. Background: Pets have an important impact on human mental, physical, social, and emotional health. It has been reported that about one third of the homeless population in Arizona has pets that are not able to gain access to veterinary care (Wang, 2015). Most homeless shelters will not allow people to access services with pets. As a consequence people will sleep out in the streets. Animals as Lifechangers and Lifesavers: Pets in the Redemption Narratives of Homeless People (Irvine, 2013) contains interviews of homeless people based on their life stories. A common theme among interviewees was that they felt they had a responsibility to their pets that served as a motivating purpose for giving up horrible personal habits because they had a sense of responsibility. Methods/Materials: Wandering Paws was launched in February 2015, but did not officially start as an eight-week study until March 2016. This pilot program serves the homeless populations' dogs and cats with veterinary care. The Arizona Humane Society was approached to acquire their services for this project including a veterinarian, a technician, and usage of their seventy-one foot mobile unit. Homeless individuals who wanted veterinary services were recruited and asked to fill out a twenty-three-question survey. Secondary data was procured from the Arizona Humane Society about the animal and services rendered for that pet. Results: Over the course of the first four weeks 22 surveys have been completed. 86% of the surveys completed indicate a strong bond between the owner and animal. The remaining 14% of the surveys completed indicate a weaker bond between the animal and owner. Conclusion/Implications: The research indicates a strong connection between most people and their animals. The veterinary services provided for the homeless population should be continued on a monthly basis as a wellness clinic in the future, as these services are in great demand.
ContributorsHowarth, Amber (Author) / DeNardo, Dale (Thesis director) / Thatcher, Craig (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
In the 1950s-60s, the United States performed nuclear testing 60 miles north of Las Vegas. The prevailing winds carried radiation from those tests across the United States. It didn't take long for groups of people to begin developing cancer, possibly as a side effect of the testing. In 1990, Congress established a program to compensate downwind victims of the test site. But one portion of one county in Arizona was never compensated, despite the impact cancer had in the area. This documentary is their story. (Documentary and website accessible at downwinddocumentary.com)
ContributorsBoehm, Jessica Ann (Author) / Elliott, Steve (Thesis director) / Dodge, Nancie (Committee member) / Snyder, Brian (Committee member) / Barrett, The Honors College (Contributor) / Walter Cronkite School of Journalism and Mass Communication (Contributor) / School of Politics and Global Studies (Contributor)
Created2014-05
Description
There are numerous strategies for determining an organism's metabolic rate, one of which is the heart rate method. The heart rate method is based on a relationship between an organism's heart rate and its oxygen consumption (V(O2)). Although validations of the heart rate method have focused on adult animals, researchers could benefit from applying this method to embryonic animals. In this study, the heart rate's reliability as an indicator of oxygen consumption in early stage embryos of reptiles (or more specifically, lizards) is evaluated. The focus is primarily on the earliest stages of cardiovascular detection. The results suggest that while it may be possible to use a reliable heart rate method to find an accurate value for oxygen consumption of a group of early embryos in lizards if the oxygen pulse can be accurately identified, it is more likely that in the earliest stages of cardiovascular development, the heart rate cannot serve as a reliable indicator of V(O2) because it may not be the primary manner in which oxygen is distributed in Sceloporus undulatus.
ContributorsHambsch, Zakary Jordan (Author) / Angilletta, Michael (Thesis director) / DeNardo, Dale (Committee member) / Condon, Catriona (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
Attitudes toward animal welfare have been evolving in our society as we have developed from early agricultural roots to an increasingly urban and technologically advanced community. However, despite the growing societal appreciation and care for animals in our homes and backyards, veterinarians are still faced with cases of abuse and neglect. Although it may seem obvious for veterinarians, as animal welfare advocates, to confront this dilemma each time they are faced with it, that is not always the case. In order to assess the responsibilities of veterinarians in regard to neglect and abuse, an extensive literature review and analysis was performed and practicing veterinarians were interviewed to determine their attitudes regarding the responsibility to report suspected cases of animal neglect and abuse. Specifically, these interviews focused on such topics as the educational background of the practitioners, how empathy impacts their perception of animal welfare, their relationship with law enforcement agencies, and related questions. The study demonstrated that the most prominent factor in a veterinarian's understanding of violations of animal welfare stems from their educational background. Therefore, it is recommended that veterinary medicine programs alter their curricula to emphasize animal welfare training and the obligation of veterinarians to report suspected cases of neglect and abuse.
ContributorsMichael, Allison Therese (Author) / Minteer, Ben (Thesis director) / Ellison, Karin (Committee member) / DeNardo, Dale (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-12