ASU Electronic Theses and Dissertations
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.
Displaying 1 - 4 of 4
Filtering by
- All Subjects: Biochemistry
- Creators: Francisco, Wilson A
- Creators: Johnston, Carol S
Description
Mexican Americans have an increased risk for type 2 diabetes and premature cardiovascular disease (CVD). The association of hyperglycemia with traditional CVD risk factors in this population has been established, but there is limited data regarding other non-traditional CVD risk factors. Thus, this cross-sectional study was conducted to evaluate CVD risk among Mexican Americans by measuring concentrations of lipids, high-sensitivity C-reactive protein (hsCRP), and cholesterol in low-density-lipoprotein (LDL) and high-density-lipoprotein (HDL) subfractions. Eighty overweight/obese Mexican-American adults participating in the Maricopa Insulin Resistance Initiative were randomly selected from each of the following four groups (n = 20 per group): nomolipidemic
ormoglycemic controls (NC), dyslipidemic
ormoglycemic (DN), dyslipidemic/prediabetic (DPD) and dyslipidemic/diabetic (DD). Total cholesterol (TC) was 30% higher among DD than in NC participants (p<0.0001). The DPD group had 27% and 12% higher LDL-C concentrations than the NC and DN groups, respectively. Similarly, LDL-C was 29% and 13% higher in DD than in NC and DN participants (p=0.013). An increasing trend was observed in %10-year CVD risk with increasing degree of hyperglycemia (p<0.0001). The NC group had less cholesterol in sdLDL particles than dyslipidemic groups, regardless of glycemic status (p<0.0001). When hyperglycemia was part of the phenotype (DPD and DD), there was a greater proportion of total and HDL-C in sHDL particles in dyslipidemic individuals than in NC (p=0.023; p<0.0001; respectively). Percent 10-year CVD risk was positively correlated with triglyceride (TG) (r=0.384, p<0.0001), TC (r=0.340, p<0.05), cholesterol in sdLDL(r=0.247; p<0.05), and TC to HDL-C ratio (r=0.404, p<0.0001), and negatively correlated with HDL-C in intermediate and large HDL(r=-0.38, p=0.001; r=0.34, p=0.002, respectively). The TC/HDL-C was positively correlated with cholesterol in sdLDL particles (r=0.698, p<0.0001) and HDL-C in sHDL particles (r=0.602, p<0.0001), and negatively correlated with cholesterol in small (r=-0.35, p=0.002), intermediate (r=-0.91, p<0.0001) and large (r=-0.84, p<0.0001) HDL particles, and HDL-C in the large HDL particles (r=-0.562, p<0.0001). No significant association was found between %10-year CVD risk and hsCRP. Collectively, these results corroborate that dyslipidemic Mexican-American adults have higher CVD risk than normolipidemic individuals. Hyperglycemia may further affect CVD risk by modulating cholesterol in LDL and HDL subfractions.
ormoglycemic controls (NC), dyslipidemic
ormoglycemic (DN), dyslipidemic/prediabetic (DPD) and dyslipidemic/diabetic (DD). Total cholesterol (TC) was 30% higher among DD than in NC participants (p<0.0001). The DPD group had 27% and 12% higher LDL-C concentrations than the NC and DN groups, respectively. Similarly, LDL-C was 29% and 13% higher in DD than in NC and DN participants (p=0.013). An increasing trend was observed in %10-year CVD risk with increasing degree of hyperglycemia (p<0.0001). The NC group had less cholesterol in sdLDL particles than dyslipidemic groups, regardless of glycemic status (p<0.0001). When hyperglycemia was part of the phenotype (DPD and DD), there was a greater proportion of total and HDL-C in sHDL particles in dyslipidemic individuals than in NC (p=0.023; p<0.0001; respectively). Percent 10-year CVD risk was positively correlated with triglyceride (TG) (r=0.384, p<0.0001), TC (r=0.340, p<0.05), cholesterol in sdLDL(r=0.247; p<0.05), and TC to HDL-C ratio (r=0.404, p<0.0001), and negatively correlated with HDL-C in intermediate and large HDL(r=-0.38, p=0.001; r=0.34, p=0.002, respectively). The TC/HDL-C was positively correlated with cholesterol in sdLDL particles (r=0.698, p<0.0001) and HDL-C in sHDL particles (r=0.602, p<0.0001), and negatively correlated with cholesterol in small (r=-0.35, p=0.002), intermediate (r=-0.91, p<0.0001) and large (r=-0.84, p<0.0001) HDL particles, and HDL-C in the large HDL particles (r=-0.562, p<0.0001). No significant association was found between %10-year CVD risk and hsCRP. Collectively, these results corroborate that dyslipidemic Mexican-American adults have higher CVD risk than normolipidemic individuals. Hyperglycemia may further affect CVD risk by modulating cholesterol in LDL and HDL subfractions.
ContributorsNeupane, Srijana (Author) / Vega-Lopez, Sonia (Thesis advisor) / Shaibi, Gabriel Q (Committee member) / Johnston, Carol S (Committee member) / Arizona State University (Publisher)
Created2011
Description
The metalloenzyme quercetin 2,3-dioxygenase (QueD) catalyzes the oxidative decomposition of the aromatic compound, quercetin. The most recently characterized example is a product of the bacterium Bacillus subtilis (BsQueD); all previous examples were fungal enzymes from the genus Aspergillus (AQueD). AQueD contains a single atom of Cu(II) per monomer. However, BsQueD, over expressed in Escherichia coli, contains Mn(II) and has two metal-binding sites, and therefore two possible active sites per monomer. To understand the contribution of each site to BsQueD's activity, the N-terminal and C-terminal metal-binding sites have been mutated individually in an effort to disrupt metal binding. In wild type BsQueD, each Mn(II) is ligated by three histidines (His) and one glutamate (Glu). All efforts to mutate His residues to non-ligating residues resulted in insoluble protein or completely inactive enzyme. A soluble mutant was expressed that replaced the Glu residue with a fourth His at the N-terminal domain. This mutant (E69H) has a specific activity of 0.00572 &mumol;/min/mg, which is nearly 3000-fold lower than the rate of wild type BsQueD (15.9 &mumol;/min/mg). Further analysis of E69H by inductively couple plasma mass spectrometry revealed that this mutant contains only 0.062 mol of Mn(II) per mol of enzyme. This is evidence that disabling metal-ligation at one domain influences metal-incorporation at the other. During the course of the mutagenic study, a second, faster purification method was developed. A hexahistidine tag and an enterokinase cleavage site were fused to the N-terminus of BsQueD (6xHis-BsQueD). Active enzyme was successfully expressed and purified with a nickel column in 3 hours. This is much faster than the previous multi-column purification, which took two full days to complete. However, the concentration of soluble, purified enzyme (1.8 mg/mL) was much lower than concentrations achieved with the traditional method (30 mg/mL). While the concentration of 6xHis-BsQueD is sufficient for some analyses, there are several characterization techniques that must be conducted at higher concentrations. Therefore, it will be advantageous to continue using both purification methods in the future.
ContributorsBowen, Sara (Author) / Francisco, Wilson A (Thesis advisor) / Allen, James (Committee member) / Jones, Anne K (Committee member) / Arizona State University (Publisher)
Created2010
Description
A novel small metal-binding protein (SmbP), with only 93 residues and no similarity to other known proteins, has been isolated from the periplasm of Nitrosomonas europaea. It is characterized by its high percentage (17%) of histidines, a motif of ten repeats of seven residues, a four α-helix bundle structure, and a high binding affinity to about six equivalents of Cu2+. The goal of this study is to investigate the Cu2+ binding sites in SmbP and to understand how Cu2+ stabilizes the protein. Preliminary folding experiments indicated that Cu2+ greatly stabilizes SmbP. In this study, protein folding data from circular dichroism (CD) spectroscopy was used to elucidate the role of Cu2+ in stabilizing SmbP structure against unfolding induced by decreased pH, increased temperature, and chemical denaturants. The significant stabilization effects of Cu2+ were demonstrated by the observation that Cu2+-SmbP remained fully folded under extreme environmental conditions, such as acidic pH, 96 °C, and 8 M urea. Also, it was shown that Cu2+ is able to induce the refolding of unfolded SmbP in acidic solutions. These findings imply that the coordination of Cu2+ to histidine residues is responsible for the stabilization effects. The crystal structure of SmbP without Cu2+ has been determined. However, attempts to crystallize Cu2+-SmbP have not been successful. In this study, multidimensional NMR experiments were conducted in order to gain additional information regarding the Cu2+-SmbP structure, in particular its metal binding sites. Unambiguous resonance assignments were successfully made. Cα secondary chemical shifts confirmed that SmbP has a four α-helical structure. A Cu2+-protein titration experiment monitored by NMR indicated a top-to-bottom, sequential metal binding pattern for SmbP. In addition, several bioinformatics tools were used to complement the experimental approach and identity of the ligands in Cu2+-binding sites in SmbP is proposed.
ContributorsYan, Qin (Author) / Francisco, Wilson A (Thesis advisor) / Allen, James (Committee member) / Ghirlanda, Giovanna (Committee member) / Arizona State University (Publisher)
Created2010
Description
Chronic low-grade inflammation is a main pathogenic link between obesity and Type 2 Diabetes (T2D) and a putative target for treatment. While a wide array of pharmacologic agents is available to manage T2D, many patients still face perturbed glycemia and subclinical inflammation. Therefore, complementary nutraceutical strategies that target inflammation, metabolism, and resolution physiology hold promise as adjunctive options to quell the disturbed immuno-metabolic milieu observed in T2D. Omega-3 polyunsaturated fatty acids (PUFAs) and anthocyanins are two dietary components evidenced to mitigate inflammation and improve T2D risk factors, through distinct and similar targets. However, the combined use of such nutraceuticals has not yet been examined in individuals with T2D. This dissertation leveraged data from a larger randomized, double-blind, placebo-controlled trial conducted between January 2022—September 2023 investigating the use of combined supplementation (active treatment; [FOM]) of anthocyanins (600 mg/d maqui berry extract) and omega-3 PUFAs (3 g/day fish oil; 2 g/d EPA, 1 g/d DHA) for 8 weeks on cytokines and mental acuity in individuals with T2D, compared to a placebo (CON). The current study examined the effects of this supplemental strategy on markers of metabolic inflammation, oxidative stress, and cardiometabolic risk. The results indicated that a marker of sustained omega-3 dietary intake and tissue accumulation termed the Omega-3 Index was inversely associated with HbA1c (? = -8.5, 95%CI -15.1, -1.4, p = 0.022) and glucose (? = -12.4, 95%CI -22.9, -0.5, p = 0.042), after adjustment for covariates at baseline across all participants with T2D in this study. However, outcomes from linear mixed model analyses demonstrated that there were no significant differences in change from baseline between FOM and CON groups at week 8 in any of the inflammatory, oxidative stress, glycemic control, or circulating lipid markers assessed in this study. These null effects were observed despite a 93% greater increase from baseline in the Omega-3 Index observed in the FOM group compared to the CON group at week 8. Therefore, the findings do not support significant treatment effects associated with 2 months of combined marine omega-3 PUFAs and maqui berry extract on inflammatory and cardiometabolic outcomes in individuals with T2D.
ContributorsFessler, Samantha Nicole (Author) / Johnston, Carol S (Thesis advisor) / Sweazea, Karen (Committee member) / Wang, Shu (Committee member) / Kavouras, Stavros A (Committee member) / Grimm, Kevin J (Committee member) / Arizona State University (Publisher)
Created2024