Matching Items (293)
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Specific dendritic morphologies are a hallmark of neuronal identity, circuit assembly, and behaviorally relevant function. Despite the importance of dendrites in brain health and disease, the functional consequences of dendritic shape remain largely unknown. This dissertation addresses two fundamental and interrelated aspects of dendrite neurobiology. First, by utilizing the genetic

Specific dendritic morphologies are a hallmark of neuronal identity, circuit assembly, and behaviorally relevant function. Despite the importance of dendrites in brain health and disease, the functional consequences of dendritic shape remain largely unknown. This dissertation addresses two fundamental and interrelated aspects of dendrite neurobiology. First, by utilizing the genetic power of Drosophila melanogaster, these studies assess the developmental mechanisms underlying single neuron morphology, and subsequently investigate the functional and behavioral consequences resulting from developmental irregularity. Significant insights into the molecular mechanisms that contribute to dendrite development come from studies of Down syndrome cell adhesion molecule (Dscam). While these findings have been garnered primarily from sensory neurons whose arbors innervate a two-dimensional plane, it is likely that the principles apply in three-dimensional central neurons that provide the structural substrate for synaptic input and neural circuit formation. As such, this dissertation supports the hypothesis that neuron type impacts the realization of Dscam function. In fact, in Drosophila motoneurons, Dscam serves a previously unknown cell-autonomous function in dendrite growth. Dscam manipulations produced a range of dendritic phenotypes with alteration in branch number and length. Subsequent experiments exploited the dendritic alterations produced by Dscam manipulations in order to correlate dendritic structure with the suggested function of these neurons. These data indicate that basic motoneuron function and behavior are maintained even in the absence of all adult dendrites within the same neuron. By contrast, dendrites are required for adjusting motoneuron responses to specific challenging behavioral requirements. Here, I establish a direct link between dendritic structure and neuronal function at the level of the single cell, thus defining the structural substrates necessary for conferring various aspects of functional motor output. Taken together, information gathered from these studies can inform the quest in deciphering how complex cell morphologies and networks form and are precisely linked to their function.
ContributorsHutchinson, Katie Marie (Author) / Duch, Carsten (Thesis advisor) / Neisewander, Janet (Thesis advisor) / Newfeld, Stuart (Committee member) / Smith, Brian (Committee member) / Orchinik, Miles (Committee member) / Arizona State University (Publisher)
Created2013
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In somatic cells, the mitotic spindle apparatus is centrosomal and several isoforms of Protein Kinase C (PKC) have been associated with the mitotic spindle, but their role in stabilizing the mitotic spindle is unclear. Other protein kinases such as, Glycogen Synthase Kinase 3â (GSK3â) also have been shown to be

In somatic cells, the mitotic spindle apparatus is centrosomal and several isoforms of Protein Kinase C (PKC) have been associated with the mitotic spindle, but their role in stabilizing the mitotic spindle is unclear. Other protein kinases such as, Glycogen Synthase Kinase 3â (GSK3â) also have been shown to be associated with the mitotic spindle. In the study in chapter 2, we show the enrichment of active (phosphorylated) PKCæ at the centrosomal region of the spindle apparatus in metaphase stage of 3T3 cells. In order to understand whether the two kinases, PKC and GSK3â are associated with the mitotic spindle, first, the co-localization and close molecular proximity of PKC isoforms with GSK3â was studied in metaphase cells. Second, the involvement of inactive GSK3â in maintaining an intact mitotic spindle was shown. Third, this study showed that addition of a phospho-PKCæ specific inhibitor to cells can disrupt the mitotic spindle microtubules. The mitotic spindle at metaphase in mouse fibroblasts appears to be maintained by PKCæ acting through GSK3â. The MAPK pathway has been implicated in various functions related to cell cycle regulation. MAPKK (MEK) is part of this pathway and the extracellular regulated kinase (ERK) is its known downstream target. GSK3â and PKCæ also have been implicated in cell cycle regulation. In the study in chapter 3, we tested the effects of inhibiting MEK on the activities of ERK, GSK3â, PKCæ, and á-tubulin. Results from this study indicate that inhibition of MEK did not inhibit GSK3â and PKCæ enrichment at the centrosomes. However, the mitotic spindle showed a reduction in the pixel intensity of microtubules and also a reduction in the number of cells in each of the M-phase stages. A peptide activation inhibitor of ERK was also used. Our results indicated a decrease in mitotic spindle microtubules and an absence of cells in most of the M-phase stages. GSK3â and PKCæ enrichment were however not inhibited at the centrosomes. Taken together, the kinases GSK3â and PKCæ may not function as a part of the MAPK pathway to regulate the mitotic spindle.
ContributorsChakravadhanula, Madhavi (Author) / Capco, David G. (Thesis advisor) / Chandler, Douglas (Committee member) / Clark-Curtiss, Josephine (Committee member) / Newfeld, Stuart (Committee member) / Arizona State University (Publisher)
Created2012
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Animal shelters are stressful environments for dogs and a plethora of research has been conducted on interventions aimed at improving the welfare of these animals. One type of intervention is social interaction, either between dogs and people or dogs and conspecifics. To investigate the types of social interaction dogs engage

Animal shelters are stressful environments for dogs and a plethora of research has been conducted on interventions aimed at improving the welfare of these animals. One type of intervention is social interaction, either between dogs and people or dogs and conspecifics. To investigate the types of social interaction dogs engage in and the impact of that contact on their welfare, 12 dogs were enrolled to participate in group sessions with other dogs, supervised by staff, in a shelter setting. There were three, 15-minute sessions per day across three days in which groups of two to four dogs were observed and recorded on video. These videos were then analyzed per dog for three types of interactions: dog-dog, dog-human, and dog-environment. It was found that the dogs spent significantly more time engaging with the staff members in the room than with conspecifics or the environment. Physiological measurements, including cortisol and S-IgA levels, were taken using urinary and fecal samples obtained both in the morning prior to these interaction sessions and after the final interaction of the day. No significant correlations were found between the amount of time that the dogs spent in each type of interaction and dogs’ cortisol or S-IgA levels. However, smaller statistical effects suggest that human interaction may correspond with decreased stress the day after interaction while conspecific interaction may be related to increases in stress the following day. Overall, these findings suggest that social interaction, particularly with people, may be beneficial, and should be further explored as a method to enhance the well-being of shelter dogs.

ContributorsVollin, Larissa Foray (Author) / Wynne, Clive (Thesis director) / Gilchrist, Rachel (Committee member) / School of Life Sciences (Contributor) / School of Music, Dance and Theatre (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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A literature review summarizing the current status of conservation efforts of the Mojave Desert tortoise (Gopherus agassizii) including a brief overview of the Endangered Species Act (ESA) and its applicability to this species' conservation. A genetic and physiological comparison of the morphologically similar Mojave species with the Sonoran (Gopherus morafkai)

A literature review summarizing the current status of conservation efforts of the Mojave Desert tortoise (Gopherus agassizii) including a brief overview of the Endangered Species Act (ESA) and its applicability to this species' conservation. A genetic and physiological comparison of the morphologically similar Mojave species with the Sonoran (Gopherus morafkai) species proceeded by an analysis of if and how the ESA should apply to the Sonoran population. Analysis of current plans and interagency cooperations followed by a multi-step proposal on how best to conserve the Sonoran population of Desert tortoise.
ContributorsKulik, Elise Chikako (Author) / Kusumi, Kenro (Thesis director) / Tollis, Marc (Committee member) / Wilson Sayres, Melissa (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / School of Life Sciences (Contributor)
Created2015-05
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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

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
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This study was conducted in order to create a brief task that more efficiently studies the memory of young and old dogs compared to previous dog radial arm mazes. The hypotheses were older dogs would perform worse than younger dogs, brief tasks with longer delays and the presence of an

This study was conducted in order to create a brief task that more efficiently studies the memory of young and old dogs compared to previous dog radial arm mazes. The hypotheses were older dogs would perform worse than younger dogs, brief tasks with longer delays and the presence of an occluder would produce worse results, and the brief task with the longest delay period without an occluder would be most correlated to the radial arm maze. 45 dogs were tested from a previous sample that had participated in a radial arm maze experiment. The dogs were tested in their owner's homes and watched the researcher place a treat behind one of two boxes. Dogs then waited during different delay periods, of 15, 30, or 45 seconds, and with or without an occluder, which was a curtain. Then, the dog was released to see if it could still remember which box the treat was behind. The results supported all the hypotheses, except the 45-second brief task with an occluder was most correlated the radial arm maze. Additionally, the dogs that had to be excluded from the radial arm maze still had a similar range of results on the brief tasks as dogs that were able to complete the radial arm maze. These results confirm the radial arm maze is very difficult and strenuous on dogs, but the brief task is correlated and probably much more effective at studying memory without these issues. This study can help researchers perfect this simple task in order to study many dogs much quicker and collect more information on dogs' memory. Future studies could overcome limitations including dogs that were not motivated by treats or that were too old to stand up. Specific breeds could be tested or longitudinal studies could be conducted to find differences in memory over time. In the future, this can hopefully relate to human cognitive decline knowledge, as dogs show similar cognitive decline to humans, and help find treatments for cognitive diseases.
ContributorsGlomski, Marissa (Author) / Wynne, Clive (Thesis director) / Presson, Clive (Committee member) / Brewer, Gene (Committee member) / Department of Psychology (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12
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Identifying disease biomarkers may aid in the early detection of breast cancer and improve patient outcomes. Recent evidence suggests that tumors are immunogenic and therefore patients may launch an autoantibody response to tumor associated antigens. Single-chain variable fragments of autoantibodies derived from regional lymph node B cells of breast cancer

Identifying disease biomarkers may aid in the early detection of breast cancer and improve patient outcomes. Recent evidence suggests that tumors are immunogenic and therefore patients may launch an autoantibody response to tumor associated antigens. Single-chain variable fragments of autoantibodies derived from regional lymph node B cells of breast cancer patients were used to discover these tumor associated biomarkers on protein microarrays. Six candidate biomarkers were discovered from 22 heavy chain-only variable region antibody fragments screened. Validation tests are necessary to confirm the tumorgenicity of these antigens. However, the use of single-chain variable autoantibody fragments presents a novel platform for diagnostics and cancer therapeutics.
ContributorsSharman, M. Camila (Author) / Magee, Dewey (Mitch) (Thesis director) / Wallstrom, Garrick (Committee member) / Petritis, Brianne (Committee member) / Barrett, The Honors College (Contributor) / College of Liberal Arts and Sciences (Contributor) / Virginia G. Piper Center for Personalized Diagnostics (Contributor) / Biodesign Institute (Contributor)
Created2012-12
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Recent studies suggest a role for the microbiota in autism spectrum disorders (ASD), potentially arising from their role in modulating the immune system and gastrointestinal (GI) function or from gut–brain interactions dependent or independent from the immune system. GI problems such as chronic constipation and/or diarrhea are common in children

Recent studies suggest a role for the microbiota in autism spectrum disorders (ASD), potentially arising from their role in modulating the immune system and gastrointestinal (GI) function or from gut–brain interactions dependent or independent from the immune system. GI problems such as chronic constipation and/or diarrhea are common in children with ASD, and significantly worsen their behavior and their quality of life. Here we first summarize previously published data supporting that GI dysfunction is common in individuals with ASD and the role of the microbiota in ASD. Second, by comparing with other publically available microbiome datasets, we provide some evidence that the shifted microbiota can be a result of westernization and that this shift could also be framing an altered immune system. Third, we explore the possibility that gut–brain interactions could also be a direct result of microbially produced metabolites.

ContributorsKrajmalnik-Brown, Rosa (Author) / Lozupone, Catherine (Author) / Kang, Dae Wook (Author) / Adams, James (Author) / Biodesign Institute (Contributor)
Created2015-03-12
Description

Personality testing in dogs has become a controversial topic in the dog community in the last few years. These assessments have been used among owners, shelters, working dog trainers, breeders, and researchers to identify patterns of behavior that may lead to insight about a dog’s personality. Due to inconsistencies in

Personality testing in dogs has become a controversial topic in the dog community in the last few years. These assessments have been used among owners, shelters, working dog trainers, breeders, and researchers to identify patterns of behavior that may lead to insight about a dog’s personality. Due to inconsistencies in terminology and validity testing, these personality tests have lost a notable amount of credibility. Focusing on questionnaire and behavioral based testing, this literature review aims to evaluate the significance of personality testing within the dog community. Each assessment will be analyzed for measurements and validity, as well as potential drawbacks and benefits. Four prominent personality assessments will be discussed in depth. These assessments include C-BARQ, DPQ, SAFER, and VIDOPET. I advocate for a mixed assessment model approach and highlight the benefits of expanding personality testing into genetic research.

ContributorsBedeir, Amy Amira (Author) / Wynne, Clive (Thesis director) / Van Bourg, Joshua (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Brief memory tasks for use with pet dogs were developed using radial arm maze performance as a standard comparison measurement of memory capacity. Healthy pet dogs were first tested in a radial arm maze, where more errors made in completing the maze indicated poorer memory. These dogs were later tested

Brief memory tasks for use with pet dogs were developed using radial arm maze performance as a standard comparison measurement of memory capacity. Healthy pet dogs were first tested in a radial arm maze, where more errors made in completing the maze indicated poorer memory. These dogs were later tested with five novel memory tests, three of which utilized a treat placed behind a box with an identical distracter nearby. The treat placement was shown to each dog, and a 35 second delay, a 15 second delay with occluder, or a 15 second delay with room exit was observed before the dog could approach and find the treat. It was found that errors on the delayed match to sample (35 second delay) and occluder/object permanence (15 second delay with occluder) tasks were significantly positively correlated with the average number of errors made in the 8th trial of the radial arm maze (r =.58, p<.01** and r =.49, p<.05*, respectively) indicating that these new brief tests can reliably be used to assess memory in pet dogs.
ContributorsBoileau, Rae Nicole (Author) / Wynne, Clive (Thesis director) / Knight, George (Committee member) / Bimonte-Nelson, Heather (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2015-05