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- Member of: ASU Electronic Theses and Dissertations
Description
Infections caused by the Hepatitis C Virus (HCV) are very common worldwide, affecting up to 3% of the population. Chronic infection of HCV may develop into liver cirrhosis and liver cancer which is among the top five of the most common cancers. Therefore, vaccines against HCV are under intense study in order to prevent HCV from harming people's health. The envelope protein 2 (E2) of HCV is thought to be a promising vaccine candidate because it can directly bind to a human cell receptor and plays a role in viral entry. However, the E2 protein production in cells is inefficient due to its complicated matured structure. Folding of E2 in the endoplasmic reticulum (ER) is often error-prone, resulting in production of aggregates and misfolded proteins. These incorrect forms of E2 are not functional because they are not able to bind to human cells and stimulate antibody response to inhibit this binding. This study is aimed to overcome the difficulties of HCV E2 production in plant system. Protein folding in the ER requires great assistance from molecular chaperones. Thus, in this study, two molecular chaperones in the ER, calreticulin and calnexin, were transiently overexpressed in plant leaves in order to facilitate E2 folding and production. Both of them showed benefits in increasing the yield of E2 and improving the quality of E2. In addition, poorly folded E2 accumulated in the ER may cause stress in the ER and trigger transcriptional activation of ER molecular chaperones. Therefore, a transcription factor involved in this pathway, named bZIP60, was also overexpressed in plant leaves, aiming at up-regulating a major family of molecular chaperones called BiP to assist protein folding. However, our results showed that BiP mRNA levels were not up-regulated by bZIP60, but they increased in response to E2 expression. The Western blot analysis also showed that overexpression of bZIP60 had a small effect on promoting E2 folding. Overall, this study suggested that increasing the level of specific ER molecular chaperones was an effective way to promote HCV E2 protein production and maturation.
ContributorsHong, Fan (Author) / Mason, Hugh (Thesis advisor) / Gaxiola, Roberto (Committee member) / Chang, Yung (Committee member) / Chen, Qiang (Committee member) / Arizona State University (Publisher)
Created2011
Description
Purpose: To examine: (1) whether Non-Hispanic Blacks (NHB) and Non-Hispanic Whites (NHW) with diagnosed arthritis differed in self-reported physical activity (PA) levels, (2) if NHB and NHW with arthritis differed on potential correlates of PA based on the Social Ecological Model (Mcleroy et al., 1988), and (3) if PA participation varied by race/ethnicity after controlling for age, gender, education, and BMI. Methods: This study was a secondary data analysis of data collected from 2006-2008 in Chicago, IL as part of the Midwest Roybal Center for Health Promotion. Bivariate analyses were used to assess potential differences between race in meeting either ACR or ACSM PA guidelines. Comparisons by race between potential socio-demographic correlates and meeting physical activity guidelines were assessed using Chi-squares. Potential differences by race in psychosocial, arthritis, and health-related and environmental correlates were assessed using T-tests. Finally, logistic regression analyses were used to examine if race was still associated with PA after controlling for socio-demographic characteristics. Results: A greater proportion of NHW (68.1% and 35.3%) than NHB (46.5% and 20.9%) met both the arthritis-specific and the American College of Sports Medicine (ACSM) recommendations for physical activity, respectively. NHB had significantly lower self-efficacy for exercise and reported greater impairments in physical function compared to NHW. Likewise, NHB reported more crime and less aesthetics within their neighborhood. NHW were 2.56 times more likely to meet arthritis-specific PA guidelines than NHB after controlling for age, gender, education, marital status, and BMI. In contrast, after controlling for sociodemographic characteristics, age and gender were the only significant predictors of meeting ACSM PA guidelines. Discussion: There were significant differences between NHB and NHW individuals with arthritis in meeting PA guidelines. After controlling for age, gender, education, and BMI non-Hispanic White individuals were still significantly more likely to meet PA guidelines. Interventions aimed at promoting higher levels of physical activity among individuals with arthritis need to consider neighborhood aesthetics and crime when designing programs. More arthritis-specific programs are needed in close proximity to neighborhoods in an effort to promote physical activity.
ContributorsChuran, Christopher (Author) / Der Ananian, Cheryl (Thesis advisor) / Adams, Marc (Committee member) / Campbell, Kathryn (Committee member) / Arizona State University (Publisher)
Created2013
Description
Heart failure is a major worldwide health concern and is the leading cause of hospitalization among elderly Americans. Approximately 50% of those diagnosed with heart failure have heart failure with preserved ejection fraction (HFPEF). HFPEF presents a therapeutic dilemma because pharmacological strategies that are effective for the treatment of heart failure and reduced ejection fraction have failed to show benefit in HFPEF. Long term moderate intensity exercise programs have been shown to improve diastolic function in patients HFPEF. High intensity interval training (HIIT) has been shown to improve diastolic function in patients with heart failure and reduced ejection fraction. However, the effects of high intensity interval training in patients with HFPEF are unknown. Fourteen patients with HFPEF were randomized to either: (1) a novel program of high-intensity aerobic interval training (n = 8), or (2) a commonly prescribed program of moderate-intensity (MOD) aerobic exercise training (n = 6). Before and after four weeks of exercise training, patients underwent a treadmill graded exercise test for the determination of peak oxygen uptake (VO2peak), a brachial artery reactivity test for assessment of endothelium-dependent flow-mediated dilation (BAFMD), aortic pulse wave velocity assessment as an index of vascular stiffness and two-dimensional echocardiography for assessment of left ventricular diastolic and systolic function. I hypothesized that (1) high-intensity aerobic interval training would result in superior improvements in FMD, aortic pulse wave velocity, VO2peak, diastolic function and, (2) changes in these parameters would be correlated with changes in VO2peak. The principal findings of the study were that a one month long high intensity interval training program resulted in significant improvements in diastolic function as measured by two-dimensional echocardiography [pre diastolic dysfunction (DD) grade - 2.13 + 0.4 vs. post DD grade - 1.25 + 0.7, p = 0.03]. The left atrial volume index was reduced in the HIIT group compared to MOD ( - 4.4 + 6.2 ml/m2 vs. 5.8 + 10.7 ml/m2, p = 0.02). Early mitral flow (E) improved in the HIIT group (pre - 0.93 + 0.2 m/s vs. post - 0.78 + 0.3 m/s, p = 0.03). A significant inverse correlation was observed between change in BAFMD and change in diastolic dysfunction grade (r = - 0.585, p = 0.028) when all the data were pooled. HIIT appears to be a time-efficient and safe strategy for improving diastolic function in patients with heart failure and preserved ejection fraction. These data may have implications for cardiovascular risk reduction in this population.
ContributorsAngadi, Siddhartha (Author) / Gaesser, Glenn A (Thesis advisor) / Mookadam, Farouk (Committee member) / Swan, Pamela (Committee member) / Vega-Lopez, Sonia (Committee member) / Lee, Chong (Committee member) / Arizona State University (Publisher)
Created2012
Description
Ebola hemorrhagic fever (EHF) is a severe and often fatal disease in human and nonhuman primates, caused by the Ebola virus. Approximately 30 years after the first epidemic, there is no vaccine or therapeutic medication approved to counter the Ebola virus. In this dissertation, a geminiviral replicon system was used to produce Ebola immune complex (EIC) in plant leaves and tested it as an Ebola vaccine. The EIC was produced in Nicotiana benthamiana leaves by fusing Ebola virus glycoprotein (GP1) to the C-terminus of heavy chain of 6D8 monoclonal antibody (mAb), which is specific to the 6D8 epitope of GP1, and co-expressing the fusion with the light chain of 6D8 mAb. EIC was purified by ammonium sulfate precipitation and protein A or protein G affinity chromatography. EIC was shown to be immunogenic in mice, but the level of antibody against Ebola virus was not sufficient to protect the mice from lethal the Ebola challenge. Hence, different adjuvants were tested in order to improve the immunogenicity of the EIC. Among several adjuvants that we used, Poly(I:C), which is a synthetic analog of double-stranded ribonucleic acid that can interact with a Toll-like receptor 3, strongly increased the efficacy of our Ebola vaccine. The mice immunized with EIC co-administered with Poly(I:C) produced high levels of neutralizing anti-Ebola IgG, and 80% of the mice were protected from the lethal Ebola virus challenge. Moreover, the EIC induced a predominant T-helper type 1 (Th1) response, whereas Poly(I:C) co-delivered with the EIC stimulated a mixed Th1/Th2 response. This result suggests that the protection against lethal Ebola challenge requires both Th1 and Th2 responses. In conclusion, this study demonstrated that the plant-produced EIC co-delivered with Poly(I:C) induced strong and protective immune responses to the Ebola virus in mice. These results support plant-produced EIC as a good vaccine candidate against the Ebola virus. It should be pursued further in primate studies, and eventually in clinical trials.
ContributorsPhoolcharoen, Waranyoo (Author) / Mason, Hugh S (Thesis advisor) / Chen, Qiang (Thesis advisor) / Arntzen, Charles J. (Committee member) / Change, Yung (Committee member) / Ma, Julian (Committee member) / Arizona State University (Publisher)
Created2010
Description
Objective: Increasing fruit/vegetable (FV) consumption and decreasing waste during the school lunch is a public health priority. Understanding how serving style of FV impacts FV consumption and waste may be an effective means to changing nutrition behaviors in schools. This study examined whether students were more likely to select, consume, and waste FV when FVs were cut vs. whole. Methods: Baseline data from the ASU School Lunch Study was used to explore associations between cut vs. whole FV serving style and objectively measured FV selection, consumption, and waste and grade level interactions among a random selection of students (n=6804; 47.8% female; 78.8% BIPOC) attending Arizona elementary, middle, and high schools (N=37). Negative binomial regression models evaluated serving style on FV weight (grams) selected, consumed, and wasted, adjusted for sociodemographics and school.
Results: Students were more likely to select cut FVs (IRR=1.11; 95% CI: 1.04, 1.18) and waste cut FVs (IRR=1.20; 95% CI: 1.04, 1.39); however, no differences were observed in the overall consumption of cut vs. whole FVs. Grade-level interactions impacted students’ selection of FVs. Middle school students had a significantly higher effect modification for the selection of cut FVs (IRR=1.18; p=0.006) compared to high school and elementary students. Further, high school students had a significantly lower effect modification for the selection of cut FVs (IRR=0.83; p=0.010) compared to middle and elementary students. No other grade-level interactions were observed.
Discussion: Serving style of FV may impact how much FV is selected and wasted, but further research is needed to determine causality between these variables.
ContributorsJames, Amber Chandarana (Author) / Bruening, Meredith (Thesis advisor) / Adams, Marc (Thesis advisor) / Koskan, Alexis (Committee member) / Arizona State University (Publisher)
Created2021
Description
Vaccines are one of the most effective ways of combating infectious diseases and developing vaccine platforms that can be used to produce vaccines can greatly assist in combating global public health threats. This dissertation focuses on the development and pre-clinical testing of vaccine platforms that are highly immunogenic, easily modifiable, economically viable to produce, and stable. These criteria are met by the recombinant immune complex (RIC) universal vaccine platform when produced in plants. The RIC platform is modeled after naturally occurring immune complexes that form when an antibody, a component of the immune system that recognizes protein structures or sequences, binds to its specific antigen, a molecule that causes an immune response. In the RIC platform, a well-characterized antibody is linked via its heavy chain, to an antigen tagged with the antibody-specific epitope. The RIC antibody binds to the epitope tags on other RIC molecules and forms highly immunogenic complexes. My research has primarily focused on the optimization of the RIC platform. First, I altered the RIC platform to enable an N-terminal antigenic fusion instead of the previous C-terminal fusion strategy. This allowed the platform to be used with antigens that require an accessible N-terminus. A mouse immunization study with a model antigen showed that the fusion location, either N-terminal or C-terminal, did not impact the immune response. Next, I studied a synergistic response that was seen upon co-delivery of RIC with virus-like particles (VLP) and showed that the synergistic response could be produced with either N-terminal or C-terminal RIC co-delivered with VLP. Since RICs are inherently insoluble due to their ability to form complexes, I also examined ways to increase RIC solubility by characterizing a panel of modified RICs and antibody-fusions. The outcome was the identification of a modified RIC that had increased solubility while retaining high immunogenicity. Finally, I modified the RIC platform to contain multiple antigenic insertion sites and explored the use of bioinformatic tools to guide the design of a broadly protective vaccine.
ContributorsPardhe, Mary (Author) / Mason, Hugh S (Thesis advisor) / Chen, Qiang (Committee member) / Mor, Tsafrir (Committee member) / Wilson, Melissa (Committee member) / Arizona State University (Publisher)
Created2021
Description
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19) that emerged from a zoonotic host at the end of 2019 and caused a public health crisis. In this collection of studies, Nicotiana benthamiana plants are used to set the foundation for producing monoclonal antibodies (mAbs) with homogeneous glycosylation to neutralize SARS-CoV-2 and potentially address the immunopathology often observed with severe COVID-19. Specifically, a mAb against the human interleukin (IL)-6 receptor (sarilumab) was generated and evaluated in vitro for its potential to reduce IL-6 signaling that has been shown to be associated with more severe cases of COVID-19. Furthermore, multiple mAbs that bind to the receptor-binding domain (RBD) of SARS-CoV-2 and efficiently neutralize the virus were developed using plant-based expression. Several of these mAbs are from different classes of RBD-binding mAbs that have distinct binding sites from one another. Several mAbs from different classes showed synergy in neutralizing the ancestral strain of SARS-CoV-2 and a smaller subset showed synergy when tested against the highly mutated Omicron (B.1.1.529) variant. Of interest, a novel RBD-binding mAb, termed 11D7, that was raised against the ancestral strain and derived from a hybridoma, appears to have an epitope on the RBD that contributes more synergy to a mAb combination that efficiently neutralizes the B.1.1.529 variant of SARS-CoV-2. This epitope was partially mapped by competitive binding and shows that it overlaps with another known antibody that binds a cryptic, distal epitope, away from the receptor binding site, giving insight into the potential mechanism by which 11D7 neutralizes SARS-CoV-2, as well as potentially allowing it to resist SARS-CoV-2 immune evasion more efficiently. Furthermore, this mAb carries a highly homogeneous glycan pattern when expressed in N. benthamiana, that may contribute to enhanced effector function and provides a tool to elucidate the precise role of crystallizable fragment (Fc)-mediated protection in SARS-CoV-2 infection. Ultimately, these studies provide evidence of the utility of plant-made mAbs to be used as cocktail members, giving clarity to the use of less potent mAbs as valuable cocktail components which will spur further investigations into how mAbs with unique epitopes work together to efficiently neutralize SARS-CoV-2.
ContributorsJugler, Collin (Author) / Chen, Qiang (Thesis advisor) / Lake, Douglas (Committee member) / Steele, Kelly (Committee member) / Mason, Hugh (Committee member) / Arizona State University (Publisher)
Created2022
Description
Scientists are entrusted with developing novel molecular strategies for effective prophylactic and therapeutic interventions. Antivirals are indispensable tools that can be targeted at viral domains directly or at cellular domains indirectly to obstruct viral infections and reduce pathogenicity. Despite their transformative potential in healthcare, to date, antivirals have been clinically approved to treat only 10 out of the greater than 200 known pathogenic human viruses. Additionally, as obligate intracellular parasites, many virus functions are intimately coupled with host cellular processes. As such, the development of a clinically relevant antiviral is challenged by the limited number of clear targets per virus and necessitates an extensive insight into these molecular processes. Compounding this challenge, many viral pathogens have evolved to evade effective antivirals. Therefore, a means to develop virus- or strain-specific antivirals without detailed insight into each idiosyncratic biochemical mechanism may aid in the development of antivirals against a larger swath of pathogens. Such an approach will tremendously benefit from having the specific molecular recognition of viral species as the lowest barrier. Here, I modify a nanobody (anti-green fluorescent protein) that specifically recognizes non-essential epitopes (glycoprotein M-pHluorin chimera) presented on the extra virion surface of a virus (Pseudorabies virus strain 486). The nanobody switches from having no inhibitory properties (tested up to 50 μM) to ∼3 nM IC50 in in vitro infectivity assays using porcine kidney (PK15) cells. The nanobody modifications use highly reliable bioconjugation to a three-dimensional wireframe deoxyribonucleic acid (DNA) origami scaffold. Mechanistic studies suggest that inhibition is mediated by the DNA origami scaffold bound to the virus particle, which obstructs the internalization of the viruses into cells, and that inhibition is enhanced by avidity resulting from multivalent virus and scaffold interactions. The assembled nanostructures demonstrate negligible cytotoxicity (<10 nM) and sufficient stability, further supporting their therapeutic potential. If translatable to other viral species and epitopes, this approach may open a new strategy that leverages existing infrastructures – monoclonal antibody development, phage display, and in vitro evolution - for rapidly developing novel antivirals in vivo.
ContributorsPradhan, Swechchha (Author) / Hariadi, Rizal (Thesis advisor) / Hogue, Ian (Committee member) / Varsani, Arvind (Committee member) / Chen, Qiang (Committee member) / Arizona State University (Publisher)
Created2022
The Association Between Time to Eat and Students Fruit & Vegetable Consumption, Selection, and Waste
Description
Background: Studies have examined student fruit/vegetable (FV) consumption, selection, and waste related to lunch duration and found that longer duration at lunch was associated with greater consumption, selection, and reduced waste. However, few studies have investigated the relationship between time to eat and FVs. The aim of this research is to analyze the relationship between objective time to students took to eat (“time to eat”) as it relates to their fruit and vegetable consumption, selection, and plate waste.in elementary, middle, and high schools. Methods: A secondary analysis of cross-sectional study of 37 Arizona schools to discover the differences in the selection, consumption, and waste of FVs from students (Full N = 2226, Elementary N = 630, Middle School N = 699, High School N = 897) using objective time to eat measures. Zero-inflated negative binomial regressions examined differences in FV grams selected, consumed, and wasted adjusted for sociodemographics including race, ethnicity, eligibility for free or reduced lunch, academic year, and sex and clustering for students within schools. Results are presented across school level (elementary, middle, and high school).
Results: The average time taken to eat ranged from 10-12 minutes for all students. The association of time to eat and lunch duration were not closely related (r=0.03, p = 0.172). In the count model for every additional minute spent, there was a 0.5% greater likelihood of selecting FVs for elementary kids among those who took any FVs. In the zero-inflated model, it was found that there was a statistically significant relationship between time spent eating and the selection of fruits and vegetables. For the total sample and high schoolers, a minute more of eating time was associated with a 4.3% and 8.8% greater odds of selecting FV. This means that longer eating time increased the likelihood of choosing fruits and vegetables. The results indicated that the longer students took to eat, the higher the likelihood of consuming more of FVs. Each 10 more minutes spent eating (i.e., time to eat) is associated with a 5% increase in grams of FV selected relative to mean (for those that chose FV) over 1 week this equates to 32 g increase of FV selected. However, for middle schoolers, the time to eat was not found to be significant in relation to the grams of fruits and vegetables consumed. There was some significance in the sociodemographic factors such as gender (all) and other (middle school). There was a relationship between time taken to eat and waste as a proportion for fruits and vegetables. For example, among those among the students who wasted something (as a proportion of selection), each additional 10 minutes of eating time was associated with a .6% decrease in waste relative to the mean (for those who chose fruits and vegetables) over a week, resulting in a decrease in waste percentage of 16.5%. Among high schoolers, males had a slightly higher odds of wasting a proportion of fruits and vegetables.
Conclusions: This study aimed to examine the association between the time students take to eat during lunch and their fruit and vegetable (FV) consumption, selection, and plate waste. The findings revealed that the time to eat was related to FV consumption, depending on the school level. However, it was not significantly associated with FV selection or waste. The study emphasized the need for further research on time to eat, distinguishing it from the duration of lunch. Longer lunch periods and adequate time could influence better food choices, increased FV consumption, and reduced waste. The study highlighted the importance of interventions and school policies promoting healthier food choices and providing sufficient time for students to eat. Future research should validate these findings and explore the impact of socialization opportunities on promoting healthier eating habits. Understanding the relationship between lunch duration, time to eat, and students' dietary behaviors can contribute to improved health outcomes and inform effective strategies in school settings.
ContributorsDandridge, Christina Marie (Author) / Adams, Marc (Thesis advisor) / Whisner, Corrie (Committee member) / Bruening, Meg (Committee member) / Arizona State University (Publisher)
Created2023
Description
Coccidioidomycosis, or valley fever (VF), is a fungal infection caused by Coccidioides that is highly endemic in southern Arizona and central California. The antibody response to infection in combination with clinical presentation and radiographic findings are often used to diagnose disease, as a highly sensitive and specific antigen-based assay has yet to be developed and commercialized. In this dissertation, a panel of monoclonal antibodies (mAbs) was generated in an attempt to identify circulating antigen in VF-positive patients. Despite utilizing a mixture of antigens, almost all mAbs obtained were against chitinase 1 (CTS1), a protein previously identified as a main component in serodiagnostic reagents. While CTS1 was undoubtedly a dominant seroreactive antigen, it was not successfully detected in circulation in patient samples prompting a shift toward further understanding the importance of CTS1 in antibody-based diagnostic assays. Interestingly, depletion of this antigen from diagnostic antigen preparations resulted in complete loss of patient IgG reactivity by immunodiffusion. This finding encouraged the development of a rapid, 10-minute point-of-care test in lateral flow assay (LFA) format to exclusively detect anti-CTS1 antibodies from human and non-human animal patients with coccidioidal infection. A CTS1 LFA was developed that demonstrated 92.9% sensitivity and 97.7% specificity when compared to current quantitative serologic assays (complement fixation and immunodiffusion). A commercially available LFA that utilizes a proprietary mixture of antigens was shown to be less sensitive (64.3%) and less specific (79.1%). This result provides evidence that a single antigen can be used to detect antibodies consistently and accurately from patients with VF. The LFA presented here shows promise as a helpful tool to rule-in or rule-out a diagnosis of VF such that patients may avoid unnecessary antibacterial treatments, improving healthcare efficiency.
ContributorsGrill, Francisca J (Author) / Lake, Douglas F (Thesis advisor) / Magee, D Mitch (Committee member) / Grys, Thomas (Committee member) / Chen, Qiang (Committee member) / Arizona State University (Publisher)
Created2023