Theses and dissertations

This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students. 

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The Effects of Acoustic Stress on the Behavior of Drosophila melanogaster

Description

Veterans are approximately 30% more likely than non-veterans to suffer from severe hearing impairment. Tinnitus, or ringing in the ears, which is increasingly common among military service men and women, has been linked to significant cognitive and psychological impairment and can be worsened by the same sounds that trigger post-traumatic…

Veterans are approximately 30% more likely than non-veterans to suffer from severe hearing impairment. Tinnitus, or ringing in the ears, which is increasingly common among military service men and women, has been linked to significant cognitive and psychological impairment and can be worsened by the same sounds that trigger post-traumatic stress disorder (PTSD). In fact, tinnitus and PTSD often present as comorbidities, and recent studies suggest these two disorders may share a common neurological pathway. Additional studies are required to better understand the connection between hearing loss and impaired cognitive function such as that observed in with PTSD. Here, we use the fruit fly, Drosophila melanogaster, to explore the relationship between hearing loss and cognitive function. Negative geotaxis climbing assays and courtship behavior analysis were used to examine neurobehavioral changes induced by prolonged, intense auditory stimulation. Preliminary results suggest that exposure to loud noise for an extended period of time significantly affected Drosophila behavior, with males being more sensitive than females. Based on our results, there appears to be a potential connection between noise exposure and behavior, further suggesting that Drosophila could be an effective model to study the link between hearing loss and PTSD.
ContributorsMichael, Allison Faye (Author) / Hackney-Price, Jennifer (Thesis director) / Sellner, Erin (Committee member) / School of Social and Behavioral Sciences (Contributor) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Flight Performance Under Temperature Extremes of Thermally Evolved Drosophila Melanogaster

Description
Species survive by adapting to what is demanded by their environment. In constant and fluctuating environments, specialist and generalists should be favored, respectively. However, the costs and benefits of adaptation can depend on a variety of factors that alter the intensity of the specialist-generalist trade-off. We examined flight performance to…

Species survive by adapting to what is demanded by their environment. In constant and fluctuating environments, specialist and generalists should be favored, respectively. However, the costs and benefits of adaptation can depend on a variety of factors that alter the intensity of the specialist-generalist trade-off. We examined flight performance to determine how well flies that evolved in constant and fluctuating temperatures acclimated to hot and cold temperatures. We predicted that flies would perform best at temperatures most similar to the ones the flies evolved at. Best performance was found when rearing and testing temperatures aligned with the temperature at which a genotype had evolved, with the generalist sharing the best and worst performance combination with the constant thermally evolved flies. Interestingly, evolved and reared temperatures had equal impact on flight performance. It was also observed that rearing at 25°C resulted in flies with the best fitness. These results contribute to the specialist-generalist theory and the idea that long term cold development is restricting in terms of range for thermal performance.
ContributorsLe Vinh Thuy, Jacqueline (Author) / Angilletta, Michael (Thesis director) / VandenBrooks, John (Committee member) / Czarnoleski, Marcin (Committee member) / School of Molecular Sciences (Contributor) / Economics Program in CLAS (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Analysis of Vitamin D and B12 Function in Drosophila melanogaster

Description
Vitamin D3 (cholecalciferol) is an essential micronutrient that plays a key role in developmental growth and lifespan in mammals. However, few studies have shown how vitamin D3 plays its vital functions in arthropods. Here, we examined the effects of full (13.3 IU/mL) and half dose (6.65 IU/mL) vitamin D3 on…

Vitamin D3 (cholecalciferol) is an essential micronutrient that plays a key role in developmental growth and lifespan in mammals. However, few studies have shown how vitamin D3 plays its vital functions in arthropods. Here, we examined the effects of full (13.3 IU/mL) and half dose (6.65 IU/mL) vitamin D3 on the growth and lifespan of Drosophila melanogaster. Vitamin B12 is another micronutrient that shows decreases absorption in elderly patients and might be linked to symptoms associated with aging rather than lifespan, but again, the effects of vitamin B12 supplementation in arthropods is poorly characterized. Results showed that both full and half doses of vitamin D3 and B12 do not significantly alter the timing of pupariation or adult eclosion. Similarly, the mortality rate of adult D. melanogaster exposed to vitamin B12 or higher doses of vitamin D3 was not significantly decreased or increased. However, a low dose of vitamin D3 did significantly lower the mortality rate of D. melanogaster. The genetic composition of Drosophila for vitamin B12 and D metabolism showed similarities in humans. However, there are no biological evidences if these genes are functional thus, this may explain the results of this study.
ContributorsRebonza, Edzel May Suico (Author) / Hackney Price, Jennifer (Thesis director) / Jurutka, Peter (Committee member) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05

Flight performance and thermal tolerance of flies acclimated to hypoxia or hyperoxia

Description
Animals are thought to die at high temperatures because proteins and cell membranes lose their structural integrity. Alternatively, a newer hypothesis (the oxygen and capacity limitation of thermal tolerance, or OCLTT) states that death occurs because oxygen supply becomes limited at high temperatures. Consequently, animals exposed to hypoxia are more…

Animals are thought to die at high temperatures because proteins and cell membranes lose their structural integrity. Alternatively, a newer hypothesis (the oxygen and capacity limitation of thermal tolerance, or OCLTT) states that death occurs because oxygen supply becomes limited at high temperatures. Consequently, animals exposed to hypoxia are more sensitive to heating than those exposed to normoxia or hyperoxia. We hypothesized that animals raised in hypoxia would acclimate to the low oxygen supply, thereby making them less sensitive to heating. Such acclimation would be expressed as greater heat tolerance and better flight performance in individuals raised at lower oxygen concentrations. We raised flies (Drosophila melanogaster) from eggs to adults under oxygen concentrations ranging from 10% to 31% and measured two aspects of thermal tolerance: 1) the time required for flies to lose motor function at 39.5°C at normoxia (21%), referred to as knock-down time, and 2) flight performance at 37°, 39°, or 41°C and 12%, 21%, or 31% oxygen. Contrary to our prediction, flies from all treatments had the same knock-down time. However, flight performance at hypoxia was greatest for flies raised in hypoxia, but flight performance at normoxia and hyperoxia was greatest for flies raised at hyperoxia. Thus, flight performance acclimated to oxygen supply during development, but heat tolerance did not. Our data does not support the OCLTT hypothesis, but instead supports the beneficial acclimation hypothesis, which proposes that acclimation improves the function of an organism during environmental change.
ContributorsShiehzadegan, Shayan (Co-author) / VadenBrooks, John (Co-author) / Le, Jackie (Co-author) / Smith, Colton (Co-author) / Shiehzadegan, Shima (Co-author) / Angilletta, Michael (Co-author, Thesis director) / VandenBrooks, John (Committee member) / Klok, C. J. (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05