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Description
Phytoplankton comprise the base of the marine food web, and, along with heterotrophic protists, they are key players in the biological pump that transports carbon from the surface to the deep ocean. In the world's subtropical oligotrophic gyres, plankton communities exhibit strong seasonality. Winter storms vent deep water into the euphotic zone, triggering a surge in primary productivity in the form of a spring phytoplankton bloom. Although the hydrographic trends of this "boom and bust" cycle have been well studied for decades, community composition and its seasonal and annual variability remains an integral subject of research. It is hypothesized here that proportions of different phytoplankton and protistan taxa vary dramatically between seasons and years, and that picoplankton represent an important component of this community and contributor to carbon in the surface ocean. Monthly samples from the Bermuda Atlantic Time-series Study (BATS) site were analyzed by epifluorescence microscopy, which permits classification by morphology, size, and trophic type. Epifluorescence counts were supplemented with flow cytometric quantification of Synechococcus, Prochlorococcus, and autotrophic pico- and nanoeukaryotes. Results from this study indicate Synechococcus and Prochlorococcus, prymnesiophytes, and hetero- and mixotrophic nano- and dinoflagellates were the major players in the BATS region plankton community. Ciliates, cryptophytes, diatoms, unidentified phototrophs, and other taxa represented rarer groups. Both flow cytometry and epifluorescence microscopy revealed Synechococcus to be most prevalent during the spring bloom. Prymnesiophytes likewise displayed distinct seasonality, with the highest concentrations again being noted during the bloom. Heterotrophic nano- and dinoflagellates, however, were most common in fall and winter. Mixotrophic dinoflagellates, while less abundant than their heterotrophic counterparts, displayed similar seasonality. A key finding of this study was the interannual variability revealed between the two years. While most taxa were more abundant in the first year, prymnesiophytes experienced much greater abundance in the second year bloom. Analyses of integrated carbon revealed further stark contrasts between the two years, both in terms of total carbon and the contributions of different groups. Total integrated carbon varied widely in the first study year but displayed less fluctuation after June 2009, and values were noticeably reduced in the second year.
ContributorsHansen, Amy (Author) / Neuer, Susanne (Thesis advisor) / Krajmalnik-Brown, Rosa (Committee member) / Sommerfeld, Milton (Committee member) / Arizona State University (Publisher)
Created2010
Description
Enzyme Replacement Therapy (ERT) is a treatment often used for patients with disorders that affect the production of various enzymes within the body, such as Cystic Fibrosis and Fabry Disease. ERT involves the use of artificially-produced enzymes, which can be derived from humans, pigs, and bacteria. Generally, enzymes derived from porcine and bacterial sources are much less expensive and more accessible than those derived from a human source. This, and the ethical implications that porcine enzymes carry, make the decision of choosing treatment simple to some and complex to others. Ethically, human-derived enzymes are often considered more ethical, while not conflicting with religious beliefs and practices as porcine-derived enzymes do.
In order to further compare porcine and human-derived enzymes, a determination of the enzyme effectiveness was done via digestion simulation. The digestion for both the human and porcine-derived enzymes consisted of three steps: oral, gastric, and intestinal. After the digestion, the absorbance for each enzyme class as well as a dilution curve of the formula used was read and recorded. Using the standard dilution curve and the absorbance values for each unknown, the formula and thus enzyme concentration that was lost through the reaction was able to be calculated.
The effectiveness of both the human and porcine enzymes, determined by the percent of formula lost, was 18.2% and 19.7%, respectively, with an error of 0.6% from the spectrophotometer, and an error of about 10% from the scale used for measuring the enzymes. This error was likely due to the small mass required of the enzymes and can be prevented in the future by performing the experiment at a larger scale.
In order to further compare porcine and human-derived enzymes, a determination of the enzyme effectiveness was done via digestion simulation. The digestion for both the human and porcine-derived enzymes consisted of three steps: oral, gastric, and intestinal. After the digestion, the absorbance for each enzyme class as well as a dilution curve of the formula used was read and recorded. Using the standard dilution curve and the absorbance values for each unknown, the formula and thus enzyme concentration that was lost through the reaction was able to be calculated.
The effectiveness of both the human and porcine enzymes, determined by the percent of formula lost, was 18.2% and 19.7%, respectively, with an error of 0.6% from the spectrophotometer, and an error of about 10% from the scale used for measuring the enzymes. This error was likely due to the small mass required of the enzymes and can be prevented in the future by performing the experiment at a larger scale.
ContributorsBlevins, Brianna R (Author) / Martin, Thomas (Thesis director) / McILwraith, Heide (Committee member) / College of Integrative Sciences and Arts (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
This project examined the relationship of science teachers' knowledge about the laws relating to the teaching of creationism/evolution in public schools using multiple demographic factors. Overall, teachers correctly identified only 7 out of 10 "yes" or "no" answers about the laws, this score is only slightly better than the expected 5 out of 10 that would be obtained from guessing. Statistically significant results in differences in the overall score on the survey were found for three major variables. Teachers who say creationism should be taught in the classroom have a lower score than those who say it should not be taught in the classroom, with a large effect size. Teachers who teach biology or a life science had significantly higher scores than those who do not, with a small/medium effect size. Older teachers had significantly higher scores than younger teachers, with a small effect size. Identifying the demographic variables that effect teacher knowledge about the laws is the first step to determining how to educate teachers on the legality teaching of creationism/evolution in public school classrooms to avoid violations of the First Amendment.
ContributorsSorge, Aidan Bennet (Author) / Parker, John (Thesis director) / Lynch, John (Committee member) / School for the Future of Innovation in Society (Contributor) / Department of English (Contributor) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Abstract
Purpose—Use a framework of genetic knowledge to investigate the association between the genotypes of various genes with phenotypes, specifically the traits of elite athletes, in order to establish a personal opinion on their relevance to athletic performance.
Methods—Assemble and analyze selected published scientific studies on genotype and athletic performance and lastly to formulate a personal opinion on the value of genetic testing of athletes. ACTN3, ACE, MSTN, and apoE were the genes selected for analyses.
Results—Two genes, ACTN3 and ACE, showed a significant relationship of genotype to phenotypic traits related to athletic performance. ApoE did not demonstrate a phenotypic association with athletic performance, however it showed a correlation with injury susceptibility leading to traumatic brain injury (TBI). MSTN did not show a phenotypic association with athletic performance.
Conclusion—When considering the multifactorial nature of athletics, each sport must be investigated individually due to the different individual requirements. ACTN3 and ACE are the most widely studied genes, therefore, considerable data on their relevance to athletic performance was easily obtained and supported a relationship between genotype and athletic performance.
Purpose—Use a framework of genetic knowledge to investigate the association between the genotypes of various genes with phenotypes, specifically the traits of elite athletes, in order to establish a personal opinion on their relevance to athletic performance.
Methods—Assemble and analyze selected published scientific studies on genotype and athletic performance and lastly to formulate a personal opinion on the value of genetic testing of athletes. ACTN3, ACE, MSTN, and apoE were the genes selected for analyses.
Results—Two genes, ACTN3 and ACE, showed a significant relationship of genotype to phenotypic traits related to athletic performance. ApoE did not demonstrate a phenotypic association with athletic performance, however it showed a correlation with injury susceptibility leading to traumatic brain injury (TBI). MSTN did not show a phenotypic association with athletic performance.
Conclusion—When considering the multifactorial nature of athletics, each sport must be investigated individually due to the different individual requirements. ACTN3 and ACE are the most widely studied genes, therefore, considerable data on their relevance to athletic performance was easily obtained and supported a relationship between genotype and athletic performance.
ContributorsMinto, Jordan Taylor- Lloyd (Author) / Steele, Kelly (Thesis director) / Penton, C. Ryan (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
It is presently believed that brown adipose tissue (BAT) is an important tissue in the control of obesity because it has the propensity to increase energy expenditure. The purpose of this study was to attempt to quantify the thermogenesis of BAT when four rats were exposed to a progression of low-fat to high-fat diet. Exogenous norepinephrine (NE) injections (dose of 0.25 mg/kg i.p.) were administered in order to elicit a temperature response, where increases in temperature indicate increased activity. Temperatures were measured via temperature sensing transponders that had been inserted at the following three sites: interscapular BAT (iBAT), the abdomen (core), and lower back (reference). Data showed increased BAT activity during acute (2-3 weeks) high fat diet (HFD) in comparison to low fat diet (LFD), but a moderate to marked decrease in BAT activity during chronic HFD (6-8 weeks) when compared to acute HFD. This suggests that while a HFD may initially stimulate BAT in the short-term, a long-term HFD diet may have negative effects on BAT activation.
ContributorsSivak, Hanna (Author) / Sweazea, Karen (Thesis director) / Herman, Richard (Committee member) / Caplan, Michael (Committee member) / School of Life Sciences (Contributor) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
"Going back as far as the time of Hippocrates, ancient Egyptians, tribal African nations, and many other early civilizations, humans used herbal remedies to treat their ailments. One such remedy was willow bark, used in tea form, to treat rheumatism and fevers. This remedy was around for many thousands of years, along with other treatments containing salicylates, although this was not understood at the time. As time has gone on, the willow bark tea has been transformed into aspirin as we know it today. In addition to its medicinal uses, aspirin has become versatile in its uses, including use in homemade facial treatments and in the garden. As beneficial as aspirin has been, there are negative consequences to its use, particularly in young children, and it may have strange effects on gender when used by pregnant women. From such humble beginnings, aspirin has been shown to be more than a simple painkiller." Topics discussed in this paper include: the origins of aspirin and its use as a medical treatment, the beginnings of aspirin as it is known today, how aspirin interacts with the body, the specific chemical reactions that occur when aspirin is taken, aspirin as part of a heart health regimen, the possible uses of aspirin in treating cancer, general information about dosages and typical aspirin use, some side effects of aspirin use, and novel uses of aspirin that are not necessarily medical in nature. The beneficial nature of aspirin and the possibilities it presents are discussed alongside information about its potential limitations and negative effects.
ContributorsMontes, Ariana (Author) / Huffman, Holly (Thesis director) / Garg, Vikas (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Characterization and Manipulation of Microbiomes From Arid Landfills for Improved Methane Production
Description
Environmentally harmful byproducts from solid waste’s decomposition, including methane (CH4) emissions, are managed through standardized landfill engineering and gas-capture mechanisms. Yet only a limited number of studies have analyzed the development and composition of Bacteria and Archaea involved in CH4 production from landfills. The objectives of this research were to compare microbiomes and bioactivity from CH4-producing communities in contrasting spatial areas of arid landfills and to tests a new technology to biostimulate CH4 production (methanogenesis) from solid waste under dynamic environmental conditions controlled in the laboratory. My hypothesis was that the diversity and abundance of methanogenic Archaea in municipal solid waste (MSW), or its leachate, play an important role on CH4 production partially attributed to the group’s wide hydrogen (H2) consumption capabilities. I tested this hypothesis by conducting complementary field observations and laboratory experiments. I describe niches of methanogenic Archaea in MSW leachate across defined areas within a single landfill, while demonstrating functional H2-dependent activity. To alleviate limited H2 bioavailability encountered in-situ, I present biostimulant feasibility and proof-of-concepts studies through the amendment of zero valent metals (ZVMs). My results demonstrate that older-aged MSW was minimally biostimulated for greater CH4 production relative to a control when exposed to iron (Fe0) or manganese (Mn0), due to highly discernable traits of soluble carbon, nitrogen, and unidentified fluorophores found in water extracts between young and old aged, starting MSW. Acetate and inhibitory H2 partial pressures accumulated in microcosms containing old-aged MSW. In a final experiment, repeated amendments of ZVMs to MSW in a 600 day mesocosm experiment mediated significantly higher CH4 concentrations and yields during the first of three ZVM injections. Fe0 and Mn0 experimental treatments at mesocosm-scale also highlighted accelerated development of seemingly important, but elusive Archaea including Methanobacteriaceae, a methane-producing family that is found in diverse environments. Also, prokaryotic classes including Candidatus Bathyarchaeota, an uncultured group commonly found in carbon-rich ecosystems, and Clostridia; All three taxa I identified as highly predictive in the time-dependent progression of MSW decomposition. Altogether, my experiments demonstrate the importance of H2 bioavailability on CH4 production and the consistent development of Methanobacteriaceae in productive MSW microbiomes.
ContributorsReynolds, Mark Christian (Author) / Cadillo-Quiroz, Hinsby (Thesis advisor) / Krajmalnik-Brown, Rosa (Thesis advisor) / Wang, Xuan (Committee member) / Kavazanjian, Edward (Committee member) / Arizona State University (Publisher)
Created2022
Description
Photosynthesis converts sunlight to biomass at a global scale. Among the photosynthetic organisms, cyanobacteria provide an excellent model to study how photosynthesis can become a practical platform of large-scale biotechnology. One novel approach involves metabolically engineering the cyanobacterium Synechocystis sp. PCC 6803 to excrete laurate, which is harvested directly.
This work begins by defining a working window of light intensity (LI). Wild-type and laurate-excreting Synechocystis required an LI of at least 5 µE/m2-s to sustain themselves, but are photo-inhibited by LI of 346 to 598 µE/m2-s.
Fixing electrons into valuable organic products, e.g., biomass and excreted laurate, is critical to success. Wild-type Synechocystis channeled 75% to 84% of its fixed electrons to biomass; laurate-excreting Synechocystis fixed 64 to 69% as biomass and 6.6% to 10% as laurate. This means that 16 to 30% of the electrons were diverted to non-valuable soluble products, and the trend was accentuated with higher LI.
How the Ci concentration depended on the pH and the nitrogen source was quantified by the proton condition and experimentally validated. Nitrate increased, ammonium decreased, but ammonium nitrate stabilized alkalinity and Ci. This finding provides a mechanistically sound tool to manage Ci and pH independently.
Independent evaluation pH and Ci on the growth kinetics of Synechocystis showed that pH 8.5 supported the fastest maximum specific growth rate (µmax): 2.4/day and 1.7/day, respectively, for the wild type and modified strains with LI of 202 µE/m2-s. Half-maximum-rate concentrations (KCi) were less than 0.1 mM, meaning that Synechocystis should attain its µmax with a modest Ci concentration (≥1.0 mM).
Biomass grown with day-night cycles had a night endogenous decay rate of 0.05-1.0/day, with decay being faster with higher LI and the beginning of dark periods. Supplying light at a fraction of daylight reduced dark decay rate and improved overall biomass productivity.
This dissertation systematically evaluates and synthesizes fundamental growth factors of cyanobacteria: light, inorganic carbon (Ci), and pH. LI remains the most critical growth condition to promote biomass productivity and desired forms of biomass, while Ci and pH now can be managed to support optimal productivity.
This work begins by defining a working window of light intensity (LI). Wild-type and laurate-excreting Synechocystis required an LI of at least 5 µE/m2-s to sustain themselves, but are photo-inhibited by LI of 346 to 598 µE/m2-s.
Fixing electrons into valuable organic products, e.g., biomass and excreted laurate, is critical to success. Wild-type Synechocystis channeled 75% to 84% of its fixed electrons to biomass; laurate-excreting Synechocystis fixed 64 to 69% as biomass and 6.6% to 10% as laurate. This means that 16 to 30% of the electrons were diverted to non-valuable soluble products, and the trend was accentuated with higher LI.
How the Ci concentration depended on the pH and the nitrogen source was quantified by the proton condition and experimentally validated. Nitrate increased, ammonium decreased, but ammonium nitrate stabilized alkalinity and Ci. This finding provides a mechanistically sound tool to manage Ci and pH independently.
Independent evaluation pH and Ci on the growth kinetics of Synechocystis showed that pH 8.5 supported the fastest maximum specific growth rate (µmax): 2.4/day and 1.7/day, respectively, for the wild type and modified strains with LI of 202 µE/m2-s. Half-maximum-rate concentrations (KCi) were less than 0.1 mM, meaning that Synechocystis should attain its µmax with a modest Ci concentration (≥1.0 mM).
Biomass grown with day-night cycles had a night endogenous decay rate of 0.05-1.0/day, with decay being faster with higher LI and the beginning of dark periods. Supplying light at a fraction of daylight reduced dark decay rate and improved overall biomass productivity.
This dissertation systematically evaluates and synthesizes fundamental growth factors of cyanobacteria: light, inorganic carbon (Ci), and pH. LI remains the most critical growth condition to promote biomass productivity and desired forms of biomass, while Ci and pH now can be managed to support optimal productivity.
ContributorsNguyen, Binh Thanh (Author) / Rittmann, Bruce E. (Thesis advisor) / Krajmalnik-Brown, Rosa (Committee member) / Westerhoff, Paul (Committee member) / Arizona State University (Publisher)
Created2015
Description
Sulfur oxidation is a process that is seen a wide variety of places. One particular place is Yellowstone national park where an abundance of hot springs are present. These acidic and hot places are prime locations for sulfur oxidation to occur. At a very basic level this is thought of as Sulfur, oxygen, and water forming sulfate and hydrogen. Many other reactions occur when an organism performs these processes, and many enzymes are used for this. This paper aimed to create, balance, and analyze the reactions involved in the paper Sulfur Oxidation in the Acidophilic Autotrophic Acidithiobacillus spp. (Wang et al., 2019) Once these reactions were balanced thermodynamic properties were found to evaluate the Gibbs Free Energy of these reactions. This allowed for a unique energy-based view of how this web of reactions relate to each other.
ContributorsMolina, Johnathan (Author) / Shock, Everett (Thesis director) / Weeks, Katelyn (Committee member) / Barrett, The Honors College (Contributor) / School of Molecular Sciences (Contributor)
Created2021-12
Description
Terrestrial hermit crabs serve an incredibly important ecological role in seed dispersal and as decomposers along coastal shorelines. They have also become quite popular in the commercial pet trade, with one species, Coenobita clypeatus, being particularly favored. Typically, these hermit crabs are easily captured and removed from the wild with little protection in their native ranges. In Hermitage Bay, Tobago, there is little information about the population numbers, composition, shell preference, and substrate preference of C. clypeatus in their native habitat. In this study, we estimated population size, gastropod shell preferences, and substrate preference conditions when clustering. We conducted mark re-capture surveys in March, July, and December 2023 and collected morphological data from captured hermit crabs. Our results indicate that the estimated population was highest in July, with the variation being significant when using the Schnabel mark re-capture estimation formula. The most common overall shell type, Columbella mercatoria (West Indian Dove Shell), was prevalent among the smaller sized, younger hermit crabs; while the larger hermit crabs preferred Cittarium pica (West Indian Top Shell). The most preferred substrate for these terrestrial hermit crabs were areas with a mixture of sand and dirt, with high amounts of vegetation and leaf waste and low amounts of human litter. These results suggest a predominantly young population and that beach cleanups should focus on removing human litter entirely, while leaving leaf waste and other fallen logs and branches and not using the collected decomposing plant matter for bonfires. This can help maintain a healthy hermit crab population that continues to benefit the coastlines in Tobago as well as other ecosystems.
ContributorsLindteigen, Amy (Author) / Briggs, Georgette (Thesis director) / Mohammed, Ryan (Committee member) / Barrett, The Honors College (Contributor) / College of Integrative Sciences and Arts (Contributor) / Dean, W.P. Carey School of Business (Contributor)
Created2024-05