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Locusts are generalist herbivores meaning that they are able to consume a variety of plants. Because of their broad diet, and ability to respond rapidly to a favorable environment with giant swarms of voracious insects, they are dangerous pests. Their potential impacts on humans increase dramatically when individuals switch from

Locusts are generalist herbivores meaning that they are able to consume a variety of plants. Because of their broad diet, and ability to respond rapidly to a favorable environment with giant swarms of voracious insects, they are dangerous pests. Their potential impacts on humans increase dramatically when individuals switch from their solitarious phase to their gregarious phase where they congregate and begin marching and eventually swarming together. These swarms, often billions strong, can consume the vegetation of enormous swaths of land and can travel hundreds of kilometers in a single day producing a complex threat to food security. To better understand the biology of these important pests we explored the gut microbiome of the South American locust (Schistocerca cancellata). We hypothesized generally that the gut microbiome in this species would be critically important as has been shown in many other species. We extracted and homogenized entire guts from male S. cancellata, and then extracted gut microbiome genomic DNA. Genomic DNA was then confirmed on a gel. The initial extractions were of poor quality for sequencing, but subsequent extractions performed by collaborators during troubleshooting at Southern Illinois University Edwardsville proved more useful and were used for PCR. This resulted in the detections of the following bacterial genera in the gut of S. cancellata: Enterobacter, Enterococcus, Serratia, Pseudomonas, Actinobacter, and Weisella. With this data, we are able to speculate about the physiological roles that they hold within the locust gut generating hypotheses for further testing. Understanding the microbial composition of this species’ gut may help us better understand the locust in general in an effort to more sustainably manage them.

ContributorsGrief, Dustin (Author) / Overson, Rick (Thesis director) / Cease, Arianne (Committee member) / Peterson, Brittany (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description
Like individual organisms, complex social groups are able to maintain predictable trajectories of growth, from initial colony foundation to mature reproductively capable units. They do so while simultaneously responding flexibly to variation in nutrient availability and intake. Leafcutter ant colonies function as tri-trophic systems, in which the ants harvest vegetation

Like individual organisms, complex social groups are able to maintain predictable trajectories of growth, from initial colony foundation to mature reproductively capable units. They do so while simultaneously responding flexibly to variation in nutrient availability and intake. Leafcutter ant colonies function as tri-trophic systems, in which the ants harvest vegetation to grow a fungus that, in turn, serves as food for the colony. Fungal growth rates and colony worker production are interdependent, regulated by nutritional and behavioral feedbacks. Fungal growth and quality are directly affected by worker foraging decisions, while worker production is, in turn, dependent on the amount and condition of the fungus. In this dissertation, I first characterized the growth relationship between the workers and the fungus of the desert leafcutter ant Acromyrmex versicolor during early stages of colony development, from colony foundation by groups of queens through the beginnings of exponential growth. I found that this relationship undergoes a period of slow growth and instability when workers first emerge, and then becomes allometrically positive. I then evaluated how mass and element ratios of resources collected by the ants are translated into fungus and worker population growth, and refuse, finding that colony digestive efficiency is comparable to digestive efficiencies of other herbivorous insects and ruminants. To test how colonies behaviorally respond to perturbations of the fungus garden, I quantified activity levels and task performance of workers in colonies with either supplemented or diminished fungus gardens, and found that colonies adjusted activity and task allocation in response to the fungus garden size. Finally, to identify possible forms of nutrient limitation, I measured how colony performance was affected by changes in the relative amounts of carbohydrates, protein, and phosphorus available in the resources used to grow the fungus garden. From this experiment, I concluded that colony growth is primarily carbohydrate-limited.
ContributorsClark, Rebecca, 1981- (Author) / Fewell, Jennifer H (Thesis advisor) / Mueller, Ulrich (Committee member) / Liebig, Juergen (Committee member) / Elser, James (Committee member) / Harrison, Jon (Committee member) / Arizona State University (Publisher)
Created2011
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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

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
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Description
Land management practices such as domestic animal grazing can alter plant communities via changes in soil structure and chemistry, species composition, and plant nutrient content. These changes can affect the abundance and quality of plants consumed by insect herbivores with consequent changes in population dynamics. These population changes can translate

Land management practices such as domestic animal grazing can alter plant communities via changes in soil structure and chemistry, species composition, and plant nutrient content. These changes can affect the abundance and quality of plants consumed by insect herbivores with consequent changes in population dynamics. These population changes can translate to massive crop damage and pest control costs. My dissertation focused on Oedaleus asiaticus, a dominant Asian locust, and had three main objectives. First, I identified morphological, physiological, and behavioral characteristics of the migratory ("brown") and non-migratory ("green") phenotypes. I found that brown morphs had longer wings, larger thoraxes and higher metabolic rates compared to green morphs, suggesting that developmental plasticity allows greater migratory capacity in the brown morph of this locust. Second, I tested the hypothesis of a causal link between livestock overgrazing and an increase in migratory swarms of O. asiaticus. Current paradigms generally assume that increased plant nitrogen (N) should enhance herbivore performance by relieving protein-limitation, increasing herbivorous insect populations. I showed, in contrast to this scenario, that host plant N-enrichment and high protein artificial diets decreased the size and viability of O. asiaticus. Plant N content was lowest and locust abundance highest in heavily livestock-grazed fields where soils were N-depleted, likely due to enhanced erosion and leaching. These results suggest that heavy livestock grazing promotes outbreaks of this locust by reducing plant protein content. Third, I tested for the influence of dietary imbalance, in conjunction with high population density, on migratory plasticity. While high population density has clearly been shown to induce the migratory morph in several locusts, the effect of diet has been unclear. I found that locusts reared at high population density and fed unfertilized plants (i.e. high quality plants for O. asiaticus) had the greatest migratory capacity, and maintained a high percent of brown locusts. These results did not support the hypothesis that poor-quality resources increased expression of migratory phenotypes. This highlights a need to develop new theoretical frameworks for predicting how environmental factors will regulate migratory plasticity in locusts and perhaps other insects.
ContributorsCease, Arianne (Author) / Harrison, Jon (Thesis advisor) / Elser, James (Thesis advisor) / DeNardo, Dale (Committee member) / Quinlan, Michael (Committee member) / Sabo, John (Committee member) / Arizona State University (Publisher)
Created2012
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

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
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Description
Background: Coccidioidomycosis (Valley Fever) is a respiratory disease that is caused by the soil-dwelling fungi Coccidioides immitis and Coccidioides posadasii. Because fungal glycosylation patterns are distinct from mammalian glycosylation patterns, we hypothesized that certain lectins (carbohydrate-binding proteins) might have differential binding properties to coccidioidal glycoproteins, and therefore serve as a

Background: Coccidioidomycosis (Valley Fever) is a respiratory disease that is caused by the soil-dwelling fungi Coccidioides immitis and Coccidioides posadasii. Because fungal glycosylation patterns are distinct from mammalian glycosylation patterns, we hypothesized that certain lectins (carbohydrate-binding proteins) might have differential binding properties to coccidioidal glycoproteins, and therefore serve as a tool for the purification and characterization of these glycoproteins from patient specimens. Materials and Methods: To identify potential Coccidioides-binding lectins, lectin-based immunohistochemistry was performed using a panel of 21 lectins on lung tissue from human patients infected with Coccidioides. Enzyme-Linked Immunosorbent Assays (ELISAs) were used to confirm and test candidate Coccidioides-binding lectins for their ability to bind to proteins from antigen preparations of laboratory-grown Coccidioides. Inhibition IHC and ELISAs were used to confirm binding properties of these lectins. SDS-PAGE and mass spectrometry were performed on eluates from coccidioidal antigen preparations run through lectin-affinity chromatography columns to characterize and identify lectin-binding coccidioidal glycoproteins. Results: Two GlcNAc-binding lectins, GSLII and sWGA, bound specifically to spherules and endospores in infected human lung tissue, and not to adjacent lung tissue. The binding of these lectins to both Coccidioides proteins in lung tissue and to coccidioidal antigen preparations was confirmed to have lectin-like characteristics. SDS-PAGE analysis of eluates from lectin-affinity chromatography demonstrated that GSLII and sWGA bind to coccidioidal glycoproteins. Mass spectrometric identification of the top ten lectin affinity-purified glycoproteins demonstrated that GSLII and sWGA share affinity to a common set of coccidioidal glycoproteins. Conclusion: This is the first report of lectins that bind specifically to Coccidioides spherules and endospores in infected humans. These lectins may have the potential to serve as tools for a better method of detection and diagnosis of Valley Fever.
ContributorsChowdhury, Yasmynn (Author) / Lake, Douglas (Thesis director) / Grys, Thomas (Committee member) / Magee, Mitchell (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2015-05
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Description
Clean water for drinking, food preparation, and bathing is essential for astronaut health and safety during long duration habitation of the International Space Station (ISS), including future missions to Mars. Despite stringent water treatment and recycling efforts on the ISS, it is impossible to completely prevent microbial contamination of onboard

Clean water for drinking, food preparation, and bathing is essential for astronaut health and safety during long duration habitation of the International Space Station (ISS), including future missions to Mars. Despite stringent water treatment and recycling efforts on the ISS, it is impossible to completely prevent microbial contamination of onboard water supplies. In this work, we used a spaceflight analogue culture system to better understand how the microgravity environment can influence the pathogenesis-related characteristics of Burkholderia cepacia complex (Bcc), an opportunistic pathogen previously recovered from the ISS water system. The results of the present study suggest that there may be important differences in how this pathogen can respond and adapt to spaceflight and other low fluid shear environments encountered during their natural life cycles. Future studies are aimed at understanding the underlying mechanisms responsible for these phenotypes.
ContributorsKang, Bianca Younseon (Author) / Nickerson, Cheryl (Thesis director) / Barrila, Jennifer (Committee member) / Ott, Mark (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Description
Vaccinia virus (VV) is a prototype virus of the Orthopox viruses. The large dsDNA virus composed of 200kbp genome contains approximately 200 genes and replicates entirely in the cytosol. Since its use as a live vaccine against smallpox that leads to the successful eradication of smallpox, Vaccinia has been intensely

Vaccinia virus (VV) is a prototype virus of the Orthopox viruses. The large dsDNA virus composed of 200kbp genome contains approximately 200 genes and replicates entirely in the cytosol. Since its use as a live vaccine against smallpox that leads to the successful eradication of smallpox, Vaccinia has been intensely studied as a vaccine vector since the large genome allows for the insertion of multiple genes. It is also studied as a molecular tool for gene therapy and gene functional study. Despite its success as a live vaccine, the vaccination causes some mild to serious bur rare adverse events in vaccinees such as generalized Vaccinia and encepharitis. Therefore, identification of virulence genes and removal of these genes to create a safer vaccine remain an important tasks. In this study, the author seeks to elucidate the possible relationship between immune evading proteins E3 and B19. VV did not allow double deletions of E3 and B19, indicating the existence of a relationship between the two genes.
ContributorsBarclay, Shizuka (Author) / Jacobs, Bertram (Thesis director) / Ugarova, Tatiana (Committee member) / Kibler, Karen (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Description
Viral infections are a significant cause of disease in humans. While some viral diseases have been eliminated, many more continue to infect millions. Viral infections are challenging to treat because viruses use host cell machinery to replicate, so it is difficult to develop drugs that can target viruses. Normally, the

Viral infections are a significant cause of disease in humans. While some viral diseases have been eliminated, many more continue to infect millions. Viral infections are challenging to treat because viruses use host cell machinery to replicate, so it is difficult to develop drugs that can target viruses. Normally, the host’s immune system is capable of destroying the virus, but during chronic infections it becomes exhausted and T cells lose their effector functions necessary for the clearance of the virus. IL-2 can help relieve this exhaustion, but causes toxicity to the body. In mice infected with chronic LCMV, IL-2 administration causes death due to pulmonary hemorrhage. CD4 deficient mice were infected with chronic LCMV and then dosed with IL-2 and survived, but mice that were deficient for CD8 T cells died, indicating that toxicity was mediated by CD8 T cells. CD8 T cells can kill infected host cells directly by producing perforin, or can produce cytokines like IFN-γ and TNF to further activate the immune system and mediate killing. Mice that were deficient in perforin died after IL-2 administration, as well as mice that were deficient in IFN-γ. Mice deficient in TNF, however, survived, indicating that TNF was mediating the toxicity in response to IL-2. There are two different receptors for TNF, p55 and p75. p55 is known as TNFR1 and has been implicated in apoptosis of virally infected cells. P75 is known as TNFR2 and is associated more with inflammation in response to infection. My hypothesis was that if TNFR2 was knocked out, infected mice would survive IL-2 dosing. When single knockouts of TNFR1 and 2 were used in an experiment however, it was found that either receptor is capable of mediating toxicity, as both experimental groups failed to survive. This is relevant to current IL-2 therapies because there is no way to eliminate a single receptor in order to reduce toxicity. Further studies exploring the anti-viral capabilities of IFN-γ are suggested.
ContributorsJarvis, Jordan Alisa (Author) / Blattman, Joseph (Thesis director) / Denzler, Karen (Committee member) / McAfee, Megan (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
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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

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