ETDs

This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.

In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.

Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.

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Biological and immunological characterization of plant-produced HIV-1 Gag/dgp41 virus-like particles

Description
Anti-retroviral drugs and AIDS prevention programs have helped to decrease the rate of new HIV-1 infections in some communities, however, a prophylactic vaccine is still needed to control the epidemic world-wide. Despite over two decades of research, a vaccine against HIV-1 remains elusive, although recent clinical trials have shown promising…

Anti-retroviral drugs and AIDS prevention programs have helped to decrease the rate of new HIV-1 infections in some communities, however, a prophylactic vaccine is still needed to control the epidemic world-wide. Despite over two decades of research, a vaccine against HIV-1 remains elusive, although recent clinical trials have shown promising results. Recent successes have focused on highly conserved, mucosally-targeted antigens within HIV-1 such as the membrane proximal external region (MPER) of the envelope protein, gp41. MPER has been shown to play critical roles in the viral mucosal transmission, though this peptide is not immunogenic on its own. Gag is a structural protein configuring the enveloped virus particles, and has been suggested to constitute a target of the cellular immunity potentially controlling the viral load. It was hypothesized that HIV-1 enveloped virus-like particles (VLPs) consisting of Gag and a deconstructed form of gp41 comprising the MPER, transmembrane, and cytoplasmic domains (dgp41) could be expressed in plants. Plant-optimized HIV-1 genes were constructed and expressed in Nicotiana benthamiana by stable transformation, or transiently using a tobacco mosaic virus-based expression system or a combination of both. Results of biophysical, biochemical and electron microscopy characterization demonstrated that plant cells could support not only the formation of HIV-1 Gag VLPs, but also the accumulation of VLPs that incorporated dgp41. These particles were purified and utilized in mice immunization experiments. Prime-boost strategies combining systemic and mucosal priming with systemic boosting using two different vaccine candidates (VLPs and CTB-MPR - a fusion of MPER and the B-subunit of cholera toxin) were administered to BALB/c mice. Serum antibody responses against both the Gag and gp41 antigens could be elicited in mice systemically primed with VLPs and these responses could be recalled following systemic boosting with VLPs. In addition, mucosal priming with VLPs allowed for a robust boosting response against Gag and gp41 when boosted with either candidate. Functional assays of these antibodies are in progress to test the antibodies' effectiveness in neutralizing and preventing mucosal transmission of HIV-1. This immunogenicity of plant-based Gag/dgp41 VLPs represents an important milestone on the road towards a broadly-efficacious and inexpensive subunit vaccine against HIV-1.
ContributorsKessans, Sarah (Author) / Mor, Tsafrir S (Thesis advisor) / Matoba, Nobuyuki (Committee member) / Mason, Hugh (Committee member) / Hogue, Brenda (Committee member) / Fromme, Petra (Committee member) / Arizona State University (Publisher)
Created2011
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Ovarian regulation of honey bee (Apis mellifera) foraging division of labor

Description
There is increasing evidence that ovarian status influcences behavioral phenotype in workers of the honey bee Apis mellifera. Honey bee workers demonstrate a complex division of labor. Young workers perform in-hive tasks (e.g. brood care), while older bees perform outside tasks (e.g. foraging for food). This age correlated division of…

There is increasing evidence that ovarian status influcences behavioral phenotype in workers of the honey bee Apis mellifera. Honey bee workers demonstrate a complex division of labor. Young workers perform in-hive tasks (e.g. brood care), while older bees perform outside tasks (e.g. foraging for food). This age correlated division of labor is known as temporal polyethism. Foragers demonstrate further division of labor with some bees biasing collection towards protein (pollen) and others towards carbohydrates (nectar). The Reproductive Ground-plan Hypothesis proposes that the ovary plays a regulatory role in foraging division of labor. European honey bee workers that have been selectively bred to store larger amounts of pollen (High strain) also have a higher number of ovarioles per ovary than workers from strains bred to store less pollen (Low strain). High strain bees also initiate foraging earlier than Low strain bees. The relationship between ovariole number and foraging behavior is also observed in wild-type Apis mellifera and Apis cerana: pollen-biased foragers have more ovarioles than nectar-biased foragers. In my first study, I investigated the pre-foraging behavioral patterns of the High and Low strain bees. I found that High strain bees progress through the temporal polyethism at a faster rate than Low strain bees. To ensure that the observed relationship between the ovary and foraging bias is not due to associated separate genes for ovary size and foraging behavior, I investigated foraging behavior of African-European backcross bees. The backcross breeding program was designed to break potential gene associations. The results from this study demonstrated the relationship between the ovary and foraging behavior, supporting the proposed causal linkage between reproductive development and behavioral phenotype. The final study was designed to elucidate a regulatory mechanism that links ovariole number with sucrose sensitivity, and loading decisions. I measured ovariole number, sucrose sensitivity and sucrose solution load size using a rate-controlled sucrose delivery system. I found an interaction effect between ovariole number and sucrose sensitivity for sucrose solution load size. This suggests that the ovary impacts carbohydrate collection through modulation of sucrose sensitivity. Because nectar and pollen collection are not independent, this would also impact protein collection.
ContributorsSiegel, Adam J (Author) / Page, Jr., Robert E (Thesis advisor) / Hamilton, Andrew L. (Committee member) / Brent, Colin S (Committee member) / Amdam, Gro V (Committee member) / McGraw, Kevin J. (Committee member) / Arizona State University (Publisher)
Created2011
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Developing a CRISPR-Mediated Knockout TCR Human T Cell Line for Use in Cloning Antigen-Specific T Cell Receptors

Description
Adoptive transfer of T cells engineered to express synthetic antigen-specific T cell receptors (TCRs) has provocative therapeutic applications for treating cancer. However, expressing these synthetic TCRs in a CD4+ T cell line is a challenge. The CD4+ Jurkat T cell line expresses endogenous TCRs that compete for space, accessory proteins,…

Adoptive transfer of T cells engineered to express synthetic antigen-specific T cell receptors (TCRs) has provocative therapeutic applications for treating cancer. However, expressing these synthetic TCRs in a CD4+ T cell line is a challenge. The CD4+ Jurkat T cell line expresses endogenous TCRs that compete for space, accessory proteins, and proliferative signaling, and there is the potential for mixed dimer formation between the α and β chains of the endogenous receptor and that of the synthetic cancer-specific TCRs. To prevent hybridization between the receptors and to ensure the binding affinity measured with flow cytometry analysis is between the tetramer and the TCR construct, a CRISPR-Cas9 gene editing pipeline was developed. The guide RNAs (gRNAs) within the complex were designed to target the constant region of the α and β chains, as they are conserved between TCR clonotypes. To minimize further interference and confer cytotoxic capabilities, gRNAs were designed to target the CD4 coreceptor, and the CD8 coreceptor was delivered in a mammalian expression vector. Further, Golden Gate cloning methods were validated in integrating the gRNAs into a CRISPR-compatible mammalian expression vector. These constructs were transfected via electroporation into CD4+ Jurkat T cells to create a CD8+ knockout TCR Jurkat cell line for broadly applicable uses in T cell immunotherapies.
ContributorsHirneise, Gabrielle Rachel (Author) / Anderson, Karen (Thesis advisor) / Mason, Hugh (Committee member) / Lake, Douglas (Committee member) / Arizona State University (Publisher)
Created2020
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Mating Biology, Social Structure, and the Evolution of Reproductive Conflict in Ants

Description
In many social groups, reproduction is shared between group members, whocompete for position in the social hierarchy for reproductive dominance. This reproductive conflict can lead to different means of enforcing reproductive differences, such as dominance displays or limited control of social hierarchy through antagonistic encounters. In eusocial insects, archetypal colonies contain a single,…

In many social groups, reproduction is shared between group members, whocompete for position in the social hierarchy for reproductive dominance. This reproductive conflict can lead to different means of enforcing reproductive differences, such as dominance displays or limited control of social hierarchy through antagonistic encounters. In eusocial insects, archetypal colonies contain a single, singly-mated fertile queen, such that no reproductive conflict exists within a colony. However, many eusocial insects deviate from this archetype and have multiply-mated queens (polyandry), multiple queens in a single colony (polygyny), or both. In these cases, reproductive conflict exists between the matrilines and patrilines represented in a colony, specifically over the production of sexual offspring. A possible outcome of reproductive conflict may be the emergence of cheating lineages, which favor the production of sexual offspring, taking advantage of the worker force produced by nestmate queens and/or patrilines. In extreme examples, inquiline social parasites may be an evolutionary consequence of reproductive conflict between nestmate queens. Inquiline social parasitism is a type of social parasitism that is usually defined by a partial or total loss of the worker caste, and the “infiltration” of host colonies to take advantage of the host worker force for reproduction. It has been hypothesized that these inquiline social parasites evolve through the speciation of cheating queen lineages from within their incipient host species. This “intra- specific” origin model involves a foundational hypothesis that the common ancestor of host and parasite (and thus, putatively, the host at the time of speciation) should be functionally polygynous, and that parasitism evolves as a “resolution” of reproductive conflict in colonies. In this dissertation, I investigate the hypothesized role of polygyny in the evolution of inquiline social parasites. I use molecular ecology and statistical approaches to validate the role of polygyny in the evolution of some inquiline social parasites. I further discuss potential mechanisms for the evolution and speciation of social parasites, and discuss future directions to elucidate these mechanisms.
ContributorsDahan, Romain Arvid (Author) / Rabeling, Christian (Thesis advisor) / Amdam, Gro V (Committee member) / Fewell, Jennifer H (Committee member) / Pratt, Stephen C (Committee member) / Rüppell, Olav (Committee member) / Arizona State University (Publisher)
Created2021