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Quantifying foraging trends in honey bees (Apis mellifera) consuming fungicide

Description

In the face of widespread pollinator decline, research has increasingly focused on ways that pesticides could be harming bees. Fungicides are pesticides that are used in greater volumes than insecticides, yet significantly fewer studies have investigated the effects of these agrochemicals. The fungicide Pristine® is commonly used on bee-pollinated crops…

In the face of widespread pollinator decline, research has increasingly focused on ways that pesticides could be harming bees. Fungicides are pesticides that are used in greater volumes than insecticides, yet significantly fewer studies have investigated the effects of these agrochemicals. The fungicide Pristine® is commonly used on bee-pollinated crops and has been shown to be detrimental to physiological processes that are key to honey bee foraging, such as digestion and learning. This study seeks to investigate how Pristine® exposure affects the amount of water, nectar, and pollen that honey bees collect. Colonies were fed either plain pollen patties or pollen patties containing 23 ppm Pristine®. Exposure to fungicide had no significant effect on corbicular pollen mass, the crop volumes of nectar or water foragers, or the proportions of foragers collecting different substances. There was a significantly higher sugar concentration in the crop of Pristine®-exposed nectar foragers (43.6%, 95% CI [38.8, 48.4]) compared to control nectar foragers (36.3%, 95% CI [31.9, 40.6]). The higher sugar concentration in the nectar of Pristine®-treated bees could indicate that the agrochemical decreases sucrose responsiveness or nutritional status in bees. Alternatively, fungicide exposure may increase the amount of sugar that bees need to make it back to the hive. Based on these results, it would appear that fungicides like Pristine® do not strongly affect the amounts of substances that honey bees collect, but it is still highly plausible that treated bees forage more slowly or with lower return rates.

ContributorsChester, Elise (Author) / Harrison, Jon (Thesis director) / DesJardins, Nicole (Committee member) / Smith, Brian (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)

Created2023-05

The Effect of Active Sensing on Odor Perception and Associative Learning in Honeybees

Description

Active sensing is a sensory phenomenon in which organisms use self-generated energy to examine their surroundings. This experiment strives to better understand active sensing in honeybees, predicting that active sensing may display itself primarily through antennae movement and that preventing antennae movement may result in differences in electroantennogram dose-response curves…

Active sensing is a sensory phenomenon in which organisms use self-generated energy to examine their surroundings. This experiment strives to better understand active sensing in honeybees, predicting that active sensing may display itself primarily through antennae movement and that preventing antennae movement may result in differences in electroantennogram dose-response curves and associative learning plasticity. This will be done by examining changes in amplitude in electroantennogram response in both fixed-antenna and free-antenna bees over the course of a differential training protocol that establishes learned behavior discrimination.

ContributorsLei, Harry (Author) / Smith, Brian (Thesis director) / Albin-Brooks, Christopher (Committee member) / Barrett, The Honors College (Contributor)

Created2023-05

Integrating Theories of Thermal Physiology to Predict Impacts of Climate Change

Description

By increasing the mean and variance of environmental temperatures, climate change has caused local extinctions and range shifts of numerous species. However, biologists disagree on which populations and species are most vulnerable to future warming. This debate arises because biologists do not know which physiological processes are most vulnerable to…

By increasing the mean and variance of environmental temperatures, climate change has caused local extinctions and range shifts of numerous species. However, biologists disagree on which populations and species are most vulnerable to future warming. This debate arises because biologists do not know which physiological processes are most vulnerable to temperature or how to model these processes in complex environments. Using the South American locust (Schistocerca cancellata) as a model system, my dissertation addressed this debate and explained how climate limits the persistence of locust populations. Locusts of S. cancellata are serious agricultural pests with occasional outbreaks covering up to 4 million km2 over six countries. Because outbreaks are largely driven by climate, understanding how climate limits the persistence of locusts may help predict crop losses in future climates. To achieve this aim, I integrated observational, experimental, and computational approaches. First, I tested a physiological model of heat stress. By measuring the heat tolerance of locusts under different oxygen concentrations, I demonstrated that heat tolerance depends on oxygen supply during the hatchling stage only. Second, I modeled the geographic distribution of locusts using physiological traits. I started by measuring thermal effects on consumption and defecation of field-captured locusts, and I then used these data to model energy gain in current and future climates. My results indicated that incorporating physiological mechanisms can improve the accuracy of models and alter predicted impacts of climate change. Finally, I explored the causes and consequences of intraspecific variation in heat tolerance. After measuring heat tolerance of locusts in different hydration states and developmental stages, I modeled survival in historical microclimates. My models indicated that recent climate change has amplified the risk of overheating for locusts, and this risk depended strongly on shade availability, hydration state, and developmental stage. Therefore, the survival of locusts in future climates will likely depend on their access to shade and water. Overall, my dissertation argues that modeling physiological mechanisms can improve the ability of biologists to predict the impacts of climate change.

ContributorsYoungblood, Jacob (Author) / Angilletta, Michael (Thesis advisor) / Buckley, Lauren (Committee member) / Cease, Arianne (Committee member) / Smith, Brian (Committee member) / Vanden Brooks, John (Committee member) / Arizona State University (Publisher)

Created2022

Area‐Based Urban Renewal Approach for Smart Cities Development in India: Challenges of Inclusion and Sustainability

Description

Cities in the Global South face rapid urbanization challenges and often suffer an acute lack of infrastructure and governance capacities. Smart Cities Mission, in India, launched in 2015, aims to offer a novel approach for urban renewal of 100 cities following an area‐based development approach, where the use of ICT…

Cities in the Global South face rapid urbanization challenges and often suffer an acute lack of infrastructure and governance capacities. Smart Cities Mission, in India, launched in 2015, aims to offer a novel approach for urban renewal of 100 cities following an area‐based development approach, where the use of ICT and digital technologies is particularly emphasized. This article presents a critical review of the design and implementation framework of this new urban renewal program across selected case‐study cities. The article examines the claims of the so‐called “smart cities” against actual urban transformation on‐ground and evaluates how “inclusive” and “sustainable” these developments are. We quantify the scale and coverage of the smart city urban renewal projects in the cities to highlight who the program includes and excludes. The article also presents a statistical analysis of the sectoral focus and budgetary allocations of the projects under the Smart Cities Mission to find an inherent bias in these smart city initiatives in terms of which types of development they promote and the ones it ignores. The findings indicate that a predominant emphasis on digital urban renewal of selected precincts and enclaves, branded as “smart cities,” leads to deepening social polarization and gentrification. The article offers crucial urban planning lessons for designing ICT‐driven urban renewal projects, while addressing critical questions around inclusion and sustainability in smart city ventures.`

ContributorsPraharaj, Sarbeswar (Author)

Created2021-05-07

Transorbital Skull Base Surgery; Exploratory Quantitative Assessment of the Microscopic and Endoscopic Surgical Corridor

Description

Transorbital surgery has gained recent notoriety due to its incorporation into endoscopic skull base surgery. The body of published literature on the field is cadaveric and observation. The pre-clinical studies are focused on the use of the endoscope only. Furthermore the methodology utilised in the published literature is inconsistent and…

Transorbital surgery has gained recent notoriety due to its incorporation into endoscopic skull base surgery. The body of published literature on the field is cadaveric and observation. The pre-clinical studies are focused on the use of the endoscope only. Furthermore the methodology utilised in the published literature is inconsistent and does not embody the optimal principles of scientific experimentation. This body of work evaluates a minimally invasive novel surgical corridor - the transorbital approach - its validity in neurosurgical practice, as well as both qualitatively and quantitatively assessing available technological advances in a robust experimental fashion. While the endoscope is an established means of visualisation used in clinical transorbital surgery, the microscope has never been assessed with respect to the transorbital approach. This question is investigated here and the anatomical and surgical benefits and limitations of microscopic visualisation demonstrated. The comparative studies provide increased knowledge on specifics pertinent to neurosurgeons and other skull base specialists when planning pre-operatively, such as pathology location, involved anatomical structures, instrument maneuvrability and the advantages and disadvantages of the distinct visualisation technologies. This is all with the intention of selecting the most suitable surgical approach and technology, specific to the patient, pathology and anatomy, so as to perform the best surgical procedure. The research findings illustrated in this body of work are diverse, reproducible and applicable. The transorbital surgical corridor has substantive potential for access to the anterior cranial fossa and specific surgical target structures. The neuroquantitative metrics investigated confirm the utility and benefits specific to the respective visualisation technologies i.e. the endoscope and microscope. The most appropriate setting wherein the approach should be used is also discussed. The transorbital corridor has impressive potential, can utilise all available technological advances, promotes multi-disciplinary co-operation and learning amongst clinicians and ultimately, is a means of improving operative patient care.

ContributorsHoulihan, Lena Mary (Author) / Preul, Mark C. (Thesis advisor) / Vernon, Brent (Thesis advisor) / O' Sullivan, Michael G.J. (Committee member) / Lawton, Michael T. (Committee member) / Santarelli, Griffin (Committee member) / Smith, Brian (Committee member) / Arizona State University (Publisher)

Created2021

How Will the COVID-19 Pandemic Affect the Future of Urban Life? : Early Evidence from Highly-Educated Respondents in the United States

Description

Attitudes and habits are extremely resistant to change, but a disruption of the magnitude of the COVID-19 pandemic has the potential to bring long-term, massive societal changes. During the pandemic, people are being compelled to experience new ways of interacting, working, learning, shopping, traveling, and eating meals. Going forward, a…

Attitudes and habits are extremely resistant to change, but a disruption of the magnitude of the COVID-19 pandemic has the potential to bring long-term, massive societal changes. During the pandemic, people are being compelled to experience new ways of interacting, working, learning, shopping, traveling, and eating meals. Going forward, a critical question is whether these experiences will result in changed behaviors and preferences in the long term. This paper presents initial findings on the likelihood of long-term changes in telework, daily travel, restaurant patronage, and air travel based on survey data collected from adults in the United States in Spring 2020. These data suggest that a sizable fraction of the increase in telework and decreases in both business air travel and restaurant patronage are likely here to stay. As for daily travel modes, public transit may not fully recover its pre-pandemic ridership levels, but many of our respondents are planning to bike and walk more than they used to. These data reflect the responses of a sample that is higher income and more highly educated than the US population. The response of these particular groups to the COVID-19 pandemic is perhaps especially important to understand, however, because their consumption patterns give them a large influence on many sectors of the economy.

ContributorsConway, Matthew Wigginton (Author) / Salon, Deborah (Author) / da Silva, Denise Capasso (Author) / Mirtich, Laura Christine (Author)

Created2020-09-03

Microbial Electrophotosynthesis: Connecting Live Cells to Artificial Electron Flux

Description

This work focuses on a novel approach to combine electrical current with cyanobacterial technology, called microbial electrophotosynthesis (MEPS). It involves using genetically modified PSII-less Synechocystis PCC 6803 cells to avoid photoinhibition, a problem that hinders green energy. In the work, a cathodic electron delivery system is employed for growth and…

This work focuses on a novel approach to combine electrical current with cyanobacterial technology, called microbial electrophotosynthesis (MEPS). It involves using genetically modified PSII-less Synechocystis PCC 6803 cells to avoid photoinhibition, a problem that hinders green energy. In the work, a cathodic electron delivery system is employed for growth and synthesis. Photoinhibition leads to the dissipation energy and lower yield, and is a major obstacle to preventing green energy from competing with fossil fuels. However, the urgent need for alternative energy sources is driven by soaring energy consumption and rising atmospheric carbon dioxide levels. When developed, MEPS can contribute to a carbon capture technology while helping with energy demands. It is thought that if PSII electron flux can be replaced with an alternative source photosynthesis could be enhanced for more effective production. MEPS has the potential to address these challenges by serving as a carbon capture technology while meeting energy demands. The idea is to replace PSII electron flux with an alternative source, which can be enhanced for higher yields in light intensities not tolerated with PSII. This research specifically focuses on creating the initiation of electron flux between the cathode and the MEPS cells while controlling and measuring the system in real time. The successful proof-of-concept work shows that MEPS can indeed generate high-light-dependent current at intensities up to 2050 µmol photons m^‒2 s^‒1, delivering 113 µmol electrons h^‒1 mg-chl^‒1. The results were further developed to characterize redox tuning for electron delivery of flux to the photosynthetic electron transport chain and redox-based kinetic analysis to model the limitations of the MEPS system.

ContributorsLewis, Christine Michelle (Author) / Torres, César I (Thesis advisor) / Fromme, Petra (Thesis advisor) / Woodbury, Neal (Committee member) / Hayes, Mark (Committee member) / Arizona State University (Publisher)

Created2023

The Development of Novel Methods for Assessing Human Olfaction Ability and the Odor Intensity of Samples

Description

Olfactory perception is a complex and multifaceted process that involves the detection of volatile organic compounds by olfactory receptor neurons in the nasal neuroepithelium. Different odorants can elicit different perceived intensities at the same concentration, while direct intensity ratings are vulnerable to framing effects and inconsistent scale usage. Odor perception…

Olfactory perception is a complex and multifaceted process that involves the detection of volatile organic compounds by olfactory receptor neurons in the nasal neuroepithelium. Different odorants can elicit different perceived intensities at the same concentration, while direct intensity ratings are vulnerable to framing effects and inconsistent scale usage. Odor perception is genetically determined, with each individual having a unique olfaction "footprint" and sensitivity levels. Genetic factors, age, gender, race, and environmental factors influence olfactory acuity. The olfactory system's complexity makes it challenging to create a standardized comparison system for olfactory perception tests. The COVID-19 pandemic has underscored the importance of olfactory dysfunction, particularly the loss of smell and taste as common symptoms. Research has demonstrated the widespread occurrence of olfactory impairment in various populations, often stemming from post-viral origins, which is the leading cause of permanent smell loss. Utilizing quantitative ranking on a qualitative scale enhances the precision and accuracy when evaluating and drawing conclusions about odor perception and how to mitigate problems caused by external factors. Pairwise comparisons enhance the accuracy and consistency of results and provide a more intuitive way of comparing items. Such ranking techniques can lead to early detection of olfactory disorders and improved diagnostic tools. The COVID-19 pandemic has shed light on the significance of olfactory dysfunction, emphasizing the need for further research and standardized testing methods in olfactory perception.

ContributorsDarden, Jaelyn (Author) / Smith, Brian (Thesis advisor) / Gerkin, Richard (Thesis advisor) / Spackman, Christy (Committee member) / Arizona State University (Publisher)

Created2023

ERK1/2 Signaling in the Development of Long-range Projection Neurons

Description

Development of the central nervous system is an incredible process that relies on multiple extracellular signaling cues and complex intracellular interactions. Approximately 1500 genes are associated with neurodevelopmental disorders, many of which are linked to a specific biochemical signaling cascade known as Extracellular-Signal Regulated Kinase (ERK1/2). Clearly defined mutations in…

Development of the central nervous system is an incredible process that relies on multiple extracellular signaling cues and complex intracellular interactions. Approximately 1500 genes are associated with neurodevelopmental disorders, many of which are linked to a specific biochemical signaling cascade known as Extracellular-Signal Regulated Kinase (ERK1/2). Clearly defined mutations in regulators of the ERK1/2 pathway cause syndromes known as the RASopathies. Symptoms include intellectual disability, developmental delay, cranio-facial and cardiac deficits. Treatments for RASopathies are limited due to an in complete understanding of ERK1/2’s role in brain development. Individuals with Neurofibromatosis Type and Noonan Syndrome, the two most common RASopathies, exhibit aberrant functional and white matter organization in non-invasive imaging studies, however, the contributions of neuronal versus oligodendrocyte deficits to this phenotype are not fully understood. To define the cellular functions of ERK1/2 in motor circuit formation, this body of work focuses on two long-range projection neuron subtypes defined by their neurotransmitter. With genetic mouse models, pathological ERK1/2 in glutamatergic neurons reduces axonal outgrowth, resulting in deficits in activity dependent gene expression and the ability to learn a motor skill task. Restricting pathological ERK1/2 within cortical layer V recapitulates these wiring deficits but not the behavioral learning phenotype. Moreover, it is uncovered that pathological ERK1/2 results in compartmentalized expression pattern of phosphorylated ERK1/2. It is not clear whether ERK1/2 functions are similar in cholinergic neuron populations that mediate attention, memory, and motor control. Basal forebrain cholinergic neuron development relies heavily on NGF-TrKA neurotrophic signaling known to activate ERK1/2. Yet the function of ERK1/2 during cholinergic neuronal specification and differentiation is poorly understood. By selectively deleting ERK1/2 in cholinergic neurons, ERK1/2 is required for activity-dependent maturation of neuromuscular junctions in juvenile mice, but not the establishment of lower motor neuron number. Moreover, ERK1/2 is not required for specification of choline acetyltransferase expressing basal forebrain cholinergic neurons by 14 days of age. However, ERK1/2 may be necessary for BFCN maturation by adulthood. Collectively, these data indicate that glutamatergic neuron-autonomous decreases in long-range axonal outgrowth and modest effects on later stages of cholinergic neuron maintenance may be important aspects of neuropathogenesis in RASopathies.

ContributorsRees, Katherina Pavy (Author) / Newbern, Jason (Thesis advisor) / Olive, Foster (Committee member) / Qiu, Shenfeng (Committee member) / Sattler, Rita (Committee member) / Smith, Brian (Committee member) / Arizona State University (Publisher)

Created2024

Interchromophoric Interactions Between TMR, Alexa, and BODIPY Fluorophores

Description

The fundamental photophysics of fluorescent probes must be understood when the probes are used in biological applications. The photophysics of BODIPY dyes inside polymeric micelles and rhodamine dyes covalently linked to proteins were studied. Hydrophobic boron-dipyrromethene (BODIPY) dyes were noncovalently encapsulated inside polymeric micelles. Absorbance and fluorescence measurements were employed…

The fundamental photophysics of fluorescent probes must be understood when the probes are used in biological applications. The photophysics of BODIPY dyes inside polymeric micelles and rhodamine dyes covalently linked to proteins were studied. Hydrophobic boron-dipyrromethene (BODIPY) dyes were noncovalently encapsulated inside polymeric micelles. Absorbance and fluorescence measurements were employed to study the photophysics of these BODIPY dyes in the micellar environments. Amphiphilic polymers with a hydrophobic character and low Critical Micelle Concentration (CMC) protected BODIPYS from the aqueous environment. Moderate dye loading conditions did not result in ground-state dimerization, and only fluorescence lifetimes and brightnesses were affected. However, amphiphilic polymers with a hydrophilic character and high CMC did not protect the BODIPYS from the aqueous environment with concomitant ground-state dimerization and quenching of the fluorescence intensity, lifetime, and brightnesses even at low dye loading conditions. At the doubly-labeled interfaces of Escherichia coli (E. coli) DNA processivity β clamps, the interchromophric interactions of four rhodamine dyes were studied: tetramethylrhodamine (TMR), TMR C6, Alexa Fluor 488, and Alexa Fluor 546. Absorbance and fluorescence measurements were performed on doubly-labeled β clamps with singly-labeled β clamps and free dyes as controls. The absorbance measurements revealed that both TMR and TMR C6 readily formed H-dimers (static quenching) at the doubly-labeled interfaces of the β clamps. However, the TMR with a longer linker (TMR C6) also displayed a degree of dynamic quenching. For Alexa Fluor 546 and Alexa Fluor 488, there were no clear signs of dimerization in the absorbance scans. However, the fluorescence properties (fluorescence intensity, lifetime, and anisotropy) of the Alexa Fluor dyes significantly changed when three methodologies were employed to disrupt the doubly-labeled interfaces: 1) the addition of sodium dodecyl sulfate (SDS) detergent to denature the proteins, 2) the addition of clamp loader (γ complex) to open one of the two interfaces, and 3) the use of subunit exchange to decrease the number of dyes per interface. These fluorescence measurements indicated that for the Alexa Fluor dyes, other interchromophoric interactions were present such as dynamic quenching and homo-Förster Resonance Energy Transfer (homo-FRET).

ContributorsDonaphon, Bryan Matthew (Author) / Levitus, Marcia (Thesis advisor) / Van Horn, Wade (Committee member) / Woodbury, Neal (Committee member) / Arizona State University (Publisher)

Created2018