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Description
Ephemeral and intermittent streams are valuable sources of surface water support in the arid ecosystems of the Southwestern United States. These streams account for over 80% of the streams in the American Southwest and their importance has been indicated in many studies. Ephemeral and intermittent streams support a wide range of plant and animal species in both continuous and episodic fashions. This study aimed to gain a better understanding of the relationship between streamflow permanence and patterns of biomass and secondary production of the riparian fauna these ecosystems support. This was accomplished through a yearlong survey in the Huachuca Mountains of Southeastern, Arizona where macroinvertebrates were collected at various sites along a gradient of streamflow permanence before, during, and after the three month monsoon season that supplies most of the annual rainfall in this region. The results of my surveys indicate that 1) Sites characterized by low streamflow permanence were more responsive to changes in precipitation than sites characterized by relatively high streamflow permanence 2) In ephemeral streams, there is a significant peak in terrestrial macroinvertebrate production and biomass both during and after the monsoon season 3) streamflow permanence may convey consistent but not exceptional secondary production whereas seasonality in rainfall may convey exceptional but episodic secondary production—more so in sites where streamflow is not consistent.
ContributorsMcCartin, Michael Patrick (Author) / Sabo, John (Thesis director) / Stromberg, Juliet (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
The Northern Gulf of California is characterized by an extreme tidal range and temperature fluctuations between seasons, as well as a large variation in microhabitats along its shoreline. As a result, the intertidal regions exhibit a diverse and distinct collection of species that have adapted to these environmental conditions, with roughly 4.6 percent being endemic. Minimal knowledge of these ecosystems existed until the 1940’s, when the renowned author John Steinbeck accompanied marine biologist Edward Ricketts on an expedition with the purpose of documenting the biodiversity of the Sea of Cortez. Today, the majority of research in the Northern Gulf of California is directed by CEDO, the Intercultural Center for the Study of Deserts and Oceans. The purpose of this project is to compile a literature review of research on the intertidal areas of the Northern Gulf and produce an illustrated brochure that educates beach visitors on local biodiversity as a collaboration with CEDO and the Clean Beaches Committee of Puerto Peñasco. This brochure aims to increase respect and appreciation for these species, as increased tourism over the past few decades has led to detrimental effects on the ecosystem. Additionally, it serves to promote the success of the Blue Flag certification of El Mirador beach in front of Manny’s Beach Club.
ContributorsPotter, Jessica Noel (Co-author) / Potter, Jessica (Co-author) / Neuer, Susanne (Thesis director) / Mangin, Katrina (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
ABSTRACT
Environmental and genetic factors influence schizophrenia risk. Individuals who have direct family members with schizophrenia have a much higher incidence. Also, acute stress or life crisis may precede the onset of the disease. This study aims to understand the effects of environment on genes related to schizophrenia risk. It investigates the impact of sleep deprivation as an acute environmental stressor on the expression of Htr2a in mice, a gene that codes for the serotonin 2A receptor (5-HT2AR). HTR2A is associated with schizophrenia risk through genetic association studies and expression is decreased in post-mortem studies of patients with the disease. Furthermore, sleep deprivation as a stressor in human trials has been shown to increase the binding capacity of 5-HT2AR. We hypothesize that sleep deprivation will increase the number of cells expressing Htr2a in the mouse anterior prefrontal cortex when compared to controls. Sleep deprived that mice express EGFP under control of the Htr2a promoter displayed anteroposterior gradients of expression across sagittal sections, with concentrations seen most densely within the prefrontal cortex as well as the anterior pretectal nucleus, thalamic nucleus, as well as the cingulate gyrus. Htr2a-EGFP expression was most densely visualized in cortical layer V and VI pyramidal neurons within the lateral prefrontal cortex of coronal sections. Furthermore, the medial prefrontal cortex contained significantly cells expressing Htr2a¬-EGFP than the lateral prefrontal cortex. Ultimately, the hypothesis was not supported and sleep deprivation did not result in more ¬Htr2a-EGFP expressing cells compared to basal levels. However, expressing cells appeared visibly brighter in sleep-deprived animals when compared to controls, indicating that the amount of intracellular Htr2a-GFP expression may be higher. This study provides strong visual representations of expression gradients following sleep deprivation as an acute stressor and paves the way for future studies regarding 5H-T2AR’s role in schizophrenia.
Environmental and genetic factors influence schizophrenia risk. Individuals who have direct family members with schizophrenia have a much higher incidence. Also, acute stress or life crisis may precede the onset of the disease. This study aims to understand the effects of environment on genes related to schizophrenia risk. It investigates the impact of sleep deprivation as an acute environmental stressor on the expression of Htr2a in mice, a gene that codes for the serotonin 2A receptor (5-HT2AR). HTR2A is associated with schizophrenia risk through genetic association studies and expression is decreased in post-mortem studies of patients with the disease. Furthermore, sleep deprivation as a stressor in human trials has been shown to increase the binding capacity of 5-HT2AR. We hypothesize that sleep deprivation will increase the number of cells expressing Htr2a in the mouse anterior prefrontal cortex when compared to controls. Sleep deprived that mice express EGFP under control of the Htr2a promoter displayed anteroposterior gradients of expression across sagittal sections, with concentrations seen most densely within the prefrontal cortex as well as the anterior pretectal nucleus, thalamic nucleus, as well as the cingulate gyrus. Htr2a-EGFP expression was most densely visualized in cortical layer V and VI pyramidal neurons within the lateral prefrontal cortex of coronal sections. Furthermore, the medial prefrontal cortex contained significantly cells expressing Htr2a¬-EGFP than the lateral prefrontal cortex. Ultimately, the hypothesis was not supported and sleep deprivation did not result in more ¬Htr2a-EGFP expressing cells compared to basal levels. However, expressing cells appeared visibly brighter in sleep-deprived animals when compared to controls, indicating that the amount of intracellular Htr2a-GFP expression may be higher. This study provides strong visual representations of expression gradients following sleep deprivation as an acute stressor and paves the way for future studies regarding 5H-T2AR’s role in schizophrenia.
ContributorsSchmitz, Kirk Andrew (Author) / Gallitano, Amelia (Thesis director) / Stout, Valerie (Committee member) / Maple, Amanda (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
This paper explores the relationship between wildfire management and the consideration of ecological and environmental concerns in Arizona. To get a proper perspective on the current state of wildfire management in Arizona, information on two wildfire management programs, the Four Forests Restoration Initiative and FireScape, was researched and analyzed, as well as contemporary fire policy, a history of wildfire in Arizona, and two recent fires in Sedona, AZ. The two fires in Sedona, the Brins Fire of 2006 and the Slide Fire of 2014, act as a focal point for this ecological management transition, as even within an 8-year period, we can see the different ways the two fires were managed and the transition to a greater ecological importance in management strategies. These all came together to give a full spectrum for the factors that have led to more ecologically-prominent wildfire management strategies in Arizona.
ContributorsGeorge-Sills, Dylan (Author) / Pyne, Stephen (Thesis director) / Hirt, Paul (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Sustainability (Contributor)
Created2015-05
Description
It is well known that deficiencies in key chemical elements (such as phosphorus, P) can reduce animal growth; however, recent empirical data have shown that high levels of dietary nutrients can also reduce animal growth. In ecological stoichiometry, this phenomenon is known as the "stoichiometric knife edge," but its underlying mechanisms are not well-known. Previous work has suggested that the crustacean zooplankter Daphnia reduces its feeding rates on phosphorus-rich food, causing low growth due to insufficient C (energy) intake. To test for this mechanism, feeding rates of Daphnia magna on algae (Scenedesmus acutus) differing in C:P ratio (P content) were determined. Overall, there was a significant difference among all treatments for feeding rate (p < 0.05) with generally higher feeding rates on P-rich algae. These data indicate that both high and low food C:P ratio do affect Daphnia feeding rate but are in contradiction with previous work that showed that P-rich food led to strong reductions in feeding rate. Additional experiments are needed to gain further insights.
ContributorsSchimpp, Sarah Ann (Author) / Elser, James (Thesis director) / Neuer, Susanne (Committee member) / Peace, Angela (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Sustainability (Contributor)
Created2014-05
ContributorsSavarese, Erica (Author) / Robert, Jason (Thesis director) / Hurlbut, Ben (Committee member) / Verrelli, Brian (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
In 2004, the South Korean geneticist Woo-Suk Hwang published what was widely regarded as the most important research result in biotechnology of the year. In the prestigious American journal Science, he claimed that he had succeeded in cloning a human blastocyst, an embryo in its early stages (Hwang et al. 2004). A year later, in a second Science article, he made the earth-shattering announcement that he had derived eleven embryonic stem cell lines using his cloning technique (Hwang et al. 2005). The international scientific community was stunned. American scientists publicly fretted that President George W. Bush‘s 2001 executive order limiting federal funding for stem-cell research in the United States had put American bioscience behind the Koreans‘ (Paarlberg 2005). These breakthroughs offered potential solutions to immune system rejection of transplanted organs and possible cures for diseases such as rheumatoid arthritis, Parkinson‘s, Down‘s syndrome, and paralysis (Svenaeus 2007). However, within a year, Hwang was exposed as a fraud who had faked his results and pressured his female colleagues to donate eggs without informed consent. Despite protests against his methods from Korean religious and nongovernmental organizations, Hwang had used his prestige to ignore his ethical obligations. The Korean government, too, was slow to investigate Hwang and to subject his work to appropriate regulation.
ContributorsClay, Anne (Author) / Hurlbut, James (Thesis director) / Maienschein, Jane (Committee member) / Marchant, Gary (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2012-12
Description
Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a devastating illness that causes the degeneration of both upper and lower motor neurons, leading to eventual muscle atrophy. ALS rapidly progresses into paralysis, with patients typically dying due to respiratory complications within three to five years from the onset of their symptoms. Even after many years of research and drug trials, there is still no cure, and current therapies only succeed in increasing life-span by approximately three months. With such limited options available for patients, there is a pressing need to not only find a cure, but also make new treatments available in order to ameliorate disease symptoms. In a genome-wide association study previously conducted by the Translational Genomics Research Institute (TGen), several single-nucleotide polymorphisms (SNPs) upstream of a novel gene, FLJ10968, were found to significantly alter risk for ALS. This novel gene acquired the name FGGY after publication of the paper. FGGY exhibits altered levels of protein expression throughout ALS disease progression in human subjects, and detectable protein and mRNA expression changes in a mouse model of ALS. We performed co-immunoprecipitation experiments coupled with mass spectrometry in order to determine which proteins are associated with FGGY. Some of these potential binding partners have been linked to RNA regulation, including regulators of the splicesomal complex such as SMN, Gemin, and hnRNP C. To further validate these findings, we have verified co-localization of these proteins with one another. We hypothesize that FGGY plays an important role in ALS pathogenesis, and we will continue to examine its biological function.
ContributorsTerzic, Barbara (Author) / Jensen, Kendall (Thesis director) / Francisco, Wilson (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)
Created2014-05
Description
The NCAA recently declared sickle cell trait (SCT) to be a risk factor for sudden illness and death among student athletes. Fetal hemoglobin (HbF) concentration in adults is negatively correlated with disease severity in sickle cell anemia, although its effect on SCT is not fully understood and the concentration is found to have high variability across populations. Two single nucleotide polymorphisms (SNPs) at the human beta globin gene cluster, rs7482144 and rs10128556, contribute to the heritable variation in HbF levels and are associated with increased HbF concentrations in adults. A sample population of NCAA football student athletes was genotyped for these two polymorphisms, and their allele frequencies were compared to those of other populations. The minor allele of both polymorphisms had allele frequencies of 0.091 in the sample population, which compared closely with other populations of recent African heritage but was significantly different from European populations. The results of this study will be included in a larger study to predict whether these among other polymorphisms can be used as markers to predict susceptibility to heat-related emergencies in NCAA student athletes with SCT, although the small sample size will delay this process until participation in the study increases. Since both rs7482144 and rs10128556 exhibit high levels of linkage disequilibrium, and as their contributions to the heritable variability of HbF concentrations tend to differ greatly between populations of different ancestry, further investigations should be aimed at distinguishing between the effects of each SNP in African American, European, and other populations represented in NCAA football before conclusions can be drawn as to their practical use as genetic markers of heat susceptibility in student athletes with SCT.
ContributorsGrieger, Ryan Wayne (Author) / Stone, Anne C. (Thesis director) / Rosenberg, Michael (Committee member) / Madrigal, Lorena (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Protein is an essential macronutrient in the human diet, but the source of this protein has both human health and environmental impacts. Health complications can result from protein deficiency, but the practices by which protein sources are raised, grown, or harvested have environmental consequences, potentially reducing biodiversity, essential habitat, and crucial stocks of natural resources. Terrestrial cultivation encroaches on natural habitats and consumes resources inefficiently, while overfishing has greatly depleted wild fishery stocks. These environmental factors, along with concerns about nutrients, contaminants and the ethics of animal protein has led to confusion about weighing the risks and benefits associated with alternative sources of protein. Providing consumers \u2014 and policy makers \u2014 with a comprehensive account of major protein sources and their impacts in an understandable form is crucial to reducing environmental degradation and improving human health. Here I provide a general framework to compare the health and environmental impacts of livestock, seafood, and plant protein, and illustrate the application of this framework with case studies for each of these categories.
ContributorsGeren, Sarah Lindsey (Author) / Gerber, Leah (Thesis director) / Smith, Andrew (Committee member) / Minteer, Ben (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Life Sciences (Contributor)
Created2014-05