Matching Items (29)
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- All Subjects: Nutrition
- Creators: School of Life Sciences
- Status: Published
Description
The portability of genetic tools from one organism to another is a cornerstone of synthetic biology. The shared biological language of DNA-to-RNA-to-protein allows for expression of polypeptide chains in phylogenetically distant organisms with little modification. The tools and contexts are diverse, ranging from catalytic RNAs in cell-free systems to bacterial proteins expressed in human cell lines, yet they exhibit an organizing principle: that genes and proteins may be treated as modular units that can be moved from their native organism to a novel one. However, protein behavior is always unpredictable; drop-in functionality is not guaranteed.
My work characterizes how two different classes of tools behave in new contexts and explores methods to improve their functionality: 1. CRISPR/Cas9 in human cells and 2. quorum sensing networks in Escherichia coli.
1. The genome-editing tool CRISPR/Cas9 has facilitated easily targeted, effective, high throughput genome editing. However, Cas9 is a bacterially derived protein and its behavior in the complex microenvironment of the eukaryotic nucleus is not well understood. Using transgenic human cell lines, I found that gene-silencing heterochromatin impacts Cas9’s ability to bind and cut DNA in a site-specific manner and I investigated ways to improve CRISPR/Cas9 function in heterochromatin.
2. Bacteria use quorum sensing to monitor population density and regulate group behaviors such as virulence, motility, and biofilm formation. Homoserine lactone (HSL) quorum sensing networks are of particular interest to synthetic biologists because they can function as “wires” to connect multiple genetic circuits. However, only four of these networks have been widely implemented in engineered systems. I selected ten quorum sensing networks based on their HSL production profiles and confirmed their functionality in E. coli, significantly expanding the quorum sensing toolset available to synthetic biologists.
My work characterizes how two different classes of tools behave in new contexts and explores methods to improve their functionality: 1. CRISPR/Cas9 in human cells and 2. quorum sensing networks in Escherichia coli.
1. The genome-editing tool CRISPR/Cas9 has facilitated easily targeted, effective, high throughput genome editing. However, Cas9 is a bacterially derived protein and its behavior in the complex microenvironment of the eukaryotic nucleus is not well understood. Using transgenic human cell lines, I found that gene-silencing heterochromatin impacts Cas9’s ability to bind and cut DNA in a site-specific manner and I investigated ways to improve CRISPR/Cas9 function in heterochromatin.
2. Bacteria use quorum sensing to monitor population density and regulate group behaviors such as virulence, motility, and biofilm formation. Homoserine lactone (HSL) quorum sensing networks are of particular interest to synthetic biologists because they can function as “wires” to connect multiple genetic circuits. However, only four of these networks have been widely implemented in engineered systems. I selected ten quorum sensing networks based on their HSL production profiles and confirmed their functionality in E. coli, significantly expanding the quorum sensing toolset available to synthetic biologists.
ContributorsDaer, René (Author) / Haynes, Karmella (Thesis advisor) / Brafman, David (Committee member) / Nielsen, David (Committee member) / Kiani, Samira (Committee member) / Arizona State University (Publisher)
Created2017
Description
Dogs' health and wellbeing is of great importance to their owners. The most common nutritional problem for pet dogs is obesity, with 22-40% of pet dogs being classified as overweight or obese. With many adverse health effects associated with obesity, this is a major concern for owners and veterinarians. The degree to which dogs enjoy consuming certain foods can have substantial implications for their body weight, so it is important to understand which aspects of foods make them appealing to dogs. This study aimed to determine whether nutritional aspects of commercial dog foods predict dogs' preferences for those foods. It was found that consumption preference is positively correlated with protein content (p < .001), therefore implying that the protein content of commercial dry dog foods may predict dogs' consumption preferences. Consumption preferences were not predicted by other available measures of food content or caloric value. Dogs' preference for foods high in protein content may be due to the satiating effect of protein. Since foods high in protein both reduce the amount of energy consumed and are found to be palatable to dogs, high-protein dog foods may offer a way for dog food manufacturers, veterinarians, and pet owners to combat obesity in pet dogs.
ContributorsPrevost, Emily Danielle (Author) / Wynne, Clive (Thesis director) / Hall, Nathaniel (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Western diets, high in dietary fat and red meat, are associated with hyperglycemia and weight gain, symptoms that promote insulin resistance and diabetes. Previous studies have shown that elevated glucose promotes glycation of circulating proteins such as albumin, which is thought to lead to hyperglycemia complications. It was hypothesized that diets with no meat consumption (pesco-vegetarian and lacto-vegetarian) would reduce protein glycation, in comparison to a diet with meat. Forty six healthy adult omnivorous subjects were randomized into one of three groups and instructed to either consume red meat (i.e. meat) or poultry twice per day (control), eliminate meat and increase fish consumption (pesco-vegetarian), or adopt a vegetarian diet devoid of fish, meat or poultry (lacto-vegetarian) for four weeks. Fasting plasma samples were collected from participants at baseline and after 4 weeks of the dietary intervention. Plasma glucose concentrations were measured using a commercially available kit. Percent glycated albumin was measured on a separate aliquot of plasma by mass spectrometry. Plasma glucose concentrations were significantly increased following 4-weeks of pesco-vegetarian diet (P=0.002, paired t-test). Neither the lacto-vegetarian (P=0.898) or the control diet (P=0.233) affected plasma glucose concentrations. Despite the significant increase in plasma glucose following a pesco-vegetarian diet, no change in percent glycated albumin was observed (P>0.50, ANOVA). These findings may indicate a protective effect of the pesco-vegetarian diet on protein glycation in the presence of elevated plasma glucose and suggest the need for additional studies to examine the link between increased fish consumption and glucose regulation.
ContributorsRaad, Noor (Author) / Sweazea, Karen (Thesis director, Committee member) / Borges, Chad (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
The transition from high school to college is, for many, a drastic change in lifestyle, social networks, and dietary choices. The prevalence of obesity in college students has been steadily increasing. Freshmen weight gains have been associated with a decrease in fruits and vegetables and an increase in unhealthy items such as desserts, alcohol, and late night snacking after dinner. A survey of college students was constructed to gauge students' perceptions of nutrition how these perceptions influenced dietary practices and behaviors. Survey results indicated that awareness of nutrition and health does not translate to dietary practices, aligning with results from previous studies. Several sex differences were noted in regards to dietary choices and perceptions, knowledge seeking behavior, and sources of information. While there were some similarities, it is clear from the results obtained that men and women have different approaches and thoughts with regard to nutrition. The results showed that college students who actively seek our nutritional information are more likely to do so in the form of social media or Internet sources. This study could be useful for those planning on conducting college-based nutritional programs in that the results indicate patterns and trends that should be taken into consideration in order for a successful nutrition intervention
ContributorsKeahon, Gabriela Estrada (Author) / Jehn, Megan (Thesis director) / Williams, Deborah (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Life Sciences (Contributor) / School for the Science of Health Care Delivery (Contributor)
Created2015-05
Description
Currently in synthetic biology only the Las, Lux, and Rhl quorum sensing pathways have been adapted for broad engineering use. Quorum sensing allows a means of cell to cell communication in which a designated sender cell produces quorum sensing molecules that modify gene expression of a designated receiver cell. While useful, these three quorum sensing pathways exhibit a nontrivial level of crosstalk, hindering robust engineering and leading to unexpected effects in a given design. To address the lack of orthogonality among these three quorum sensing pathways, previous scientists have attempted to perform directed evolution on components of the quorum sensing pathway. While a powerful tool, directed evolution is limited by the subspace that is defined by the protein. For this reason, we take an evolutionary biology approach to identify new orthogonal quorum sensing networks and test these networks for cross-talk with currently-used networks. By charting characteristics of acyl homoserine lactone (AHL) molecules used across quorum sensing pathways in nature, we have identified favorable candidate pathways likely to display orthogonality. These include Aub, Bja, Bra, Cer, Esa, Las, Lux, Rhl, Rpa, and Sin, which we have begun constructing and testing. Our synthetic circuits express GFP in response to a quorum sensing molecule, allowing quantitative measurement of orthogonality between pairs. By determining orthogonal quorum sensing pairs, we hope to identify and adapt novel quorum sensing pathways for robust use in higher-order genetic circuits.
ContributorsMuller, Ryan (Author) / Haynes, Karmella (Thesis director) / Wang, Xiao (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
With the rising prevalence of obesity and diabetes, novel treatments to help mitigate or prevent symptoms of these conditions are warranted. Prior studies have shown that fossilized plant materials found in soil lowers blood sugar in a mouse model of diabetes. The goal of this study is to determine whether a similar organometallic complex (OMC) could prevent insulin resistance in the skeletal muscle brought on by chronic high fat intake by examining the protein expression of key enzymes in the insulin signaling pathway and examining glucoregulatory measures. Six-week-old periadolescent male Sprague-Dawley rats (n=42) were randomly chosen to be fed either a high fat diet (HFD) (20% protein, 20% carbohydrates [6.8% sucrose], 60% fat) or a standard chow diet (18.9% protein, 57.33% carbohydrates, 5% fat) for 10 weeks. Rats from each diet group were then randomly assigned to one of three doses of OMC (0, 0.6, 3.0 mg/mL), which was added to their drinking water and fasting blood glucose was measured at baseline and again at 10 weeks. After 10 weeks, rats were euthanized, and soleus muscle samples were isolated, snap-frozen, and stored at -80°C until analyses. Fasting plasma glucose was measured using a commercially available glucose oxidase kit. Following 6 and 10 weeks, HFD rats developed significant hyperglycemia (p<0.001 and p=0.025) compared to chow controls which was prevented by high dose OMC (p=0.021). After 10 weeks, there were significant differences in fasting serum insulin between diets (p=0.009) where levels were higher in HFD rats. No significant difference was seen in p-PI3K expression between groups. These results suggest that OMC could prevent insulin resistance by reducing hyperglycemia. Further studies are needed to characterize the effects of diet and OMC on the insulin signaling pathway in skeletal muscle, the main site of postprandial glucose disposal. This study was supported by a grant from Isagenix International LLC as well as funds from Barrett, the Honors College at Arizona State University, Tempe Campus.
ContributorsStarr, Ashlee (Author) / Sweazea, Karen (Thesis director) / Johnston, Carol (Committee member) / Hyatt, JP (Committee member) / Sanford School of Social and Family Dynamics (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Childhood obesity is a worsening epidemic in the U.S. with substantial racial/ethnic and socioeconomic disparities. Community-based approaches are necessary to target populations that are disproportionately affected by childhood obesity. The current randomized controlled trial assessed the effects of Athletes for Life (AFL), a 12-week community-based nutrition education and physical activity program that aims to improve cardiovascular fitness and promote healthy eating among families in the South Phoenix region, relative to a control condition. One of the goals of the intervention was to increase participating children's intake of fruits/vegetables and reduce their sugar intake, measured by a parent-reported food-frequency questionnaire. Data were collected on 110 child participants aged 6-11 years old. Relative to baseline values, participants in the intervention reportedly increased their fruit intake frequency by 0.12 + 2.0 times per day, whereas the control group decreased their intake by 0.32 + 1.28 times per day (p=0.026). Participants in the intervention group also increased their vegetable intake by 0.21 + 0.65 times per day, whereas control participants decreased their intake by 0.05 + 0.72 times per day (p=0.019). Participants in the intervention group decreased their intake of sugar-sweetened beverage (SSB) intake by 0.22 + 0.62 times per day, whereas control participants decreased their intake of SSBs by 0.04 + 0.40 times per day, however, the change observed in SSB intake was not significant between groups. Lastly, frequency of sugar-laden food intake decreased by 0.86 + 1.10 times per day among the intervention group, whereas control participants increased their intake by 0.02 + 1.10 times per day (p=0.033). The AFL study may serve as a framework for future community-based interventions to promote health in underserved areas.
ContributorsCirjan, Ioana Alina (Author) / Vega-Lopez, Sonia (Thesis director) / Crespo, Noe (Committee member) / School of Nutrition and Health Promotion (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Attending college provides young adults with a major shift in environment from high school where many students are used to living at home with their parents or guardians. Students experience a newfound freedom once beginning their freshman year, especially if living in on-campus housing. Freshmen are known to gain weight during this transitory period, and this has been partially attributed to changes in eating behaviors, which makes this a population of concern. College freshmen have significant autonomy over their food choices if not living at home, due to not having parents or guardians present. In the transition to college, freshmen are able to adopt new habits, healthy or unhealthy, which could make a large impact on their health habits for the rest of their lives; this is why the freshman population is an area of concern. RESULTS: None of the relationships between social connectedness and FF consumption were found to be statistically significant. Social connectedness was not significantly related to cross-sectional FF intake at the two different phases, or longitudinally between the two phases, even after adjustments were made. Additionally, there were no gender differences present in FF consumption or social connectedness at either phase. CONCLUSION: The lack of significant findings suggest that social connectedness might not be a reason college freshmen consume FF. Students might eat with others due to the convenience of living closely to them rather than as a means to socialize. Also, factors such as time constraints and cost might have played a larger role in why students consumed FF. Future research could involve similar studies using shorter questionnaires more tailored to eating behaviors, with more detailed measures of FF consumption (e.g. What specific FF meals did you consume?) and for a longer duration of time, to allow students to become more situated in their environment and have a better knowledge of all their food options. This study was an important contribution to the sparsely researched topic of social connectedness with a large and diverse sample studied longitudinally. It was also the only study of its kind to be performed on the college population, and had potential for future health implications in obesity and chronic conditions such as hypertension and type II diabetes. Further research is warranted to evaluate the relationship between social connectedness and other eating behaviors.
ContributorsBaca, Rachel (Author) / Bruening, Meg (Thesis director) / Brennhofer, Stephanie (Committee member) / School of Life Sciences (Contributor) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Cardiovascular disease is one of the most deadly outcomes of end stage renal disease. Bioelectrical impedance is a intriguing, yet unproven method of measuring fluid buildup in the heart, and is marketed as a early diagnostic tool for onset of cardiovascular disease. In this study, selenium supplements were given to a cohort of dialysis patients in the Phoenix metro area and their fluid tolerance was measured with thoracic biolectrical impedance. BNP was used as a correlate to see if bioelectrical impedance was correlated with heart disease. The study found no correlation between BNP and bioelectrical impedance and thus was not an accurate diagnostic tool in a medical setting.
ContributorsBrown, Patrick Michael (Author) / Johnston, Carol (Thesis director) / Orchinik, Miles (Committee member) / Tingey, Michael (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)
Created2013-05
Description
Gluten is another name for natural proteins found in wheat, rye, barley and other grains that are commonly found in most boxed, pre-made, or baked items. However, the number of people diagnosed with Celiac's Disease, Non-Celiac Gluten Sensitivity, or Wheat Allergy has risen dramatically over the past few decades. In fact, the Gluten-Free Market is estimated to be worth 6.6 billion dollars by 2017. Therefore, this cookbook was made to provide quick, easy, and diverse recipes for people unable to ingest gluten without hurting their wallets.
ContributorsDas, Surina Maria (Author) / Morse, Lisa (Thesis director) / Grgich, Traci (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05