Matching Items (67)
Description
While exercising mammalian muscle increasingly relies on carbohydrates for fuel as aerobic exercise intensity rises above the moderate range, flying birds are extraordinary endurance athletes and fuel flight, a moderate-high intensity exercise, almost exclusively with lipid. In addition, Aves have long lifespans compared to weight-matched mammals. As skeletal muscle mitochondria account for the majority of oxygen consumption during aerobic exercise, the primary goal was to investigate differences in isolated muscle mitochondria between these species and to examine to what extent factors intrinsic to mitochondria may account for the behavior observed in the intact tissue and whole organism. First, maximal enzyme activities were assessed in sparrow and rat mitochondria. Citrate synthase and aspartate aminotransferase activity were higher in sparrow compared to rat mitochondria, while glutamate dehydrogenase activity was lower. Sparrow mitochondrial NAD-linked isocitrate dehydrogenase activity was dependent on phosphate, unlike the mammalian enzyme. Next, the rate of oxygen consumption (JO), electron transport chain (ETC) activity, and reactive oxygen species (ROS) production were assessed in intact mitochondria. Maximal rates of fat oxidation were lower than for carbohydrate in rat but not sparrow mitochondria. ETC activity was higher in sparrows, but no differences were found in ROS production between species. Finally, fuel selection and control of respiration at three rates between rest and maximum were assessed. Mitochondrial fuel oxidation and selection mirrored that of the whole body; in rat mitochondria the reliance on carbohydrate increased as the rate of oxygen consumption increased, whereas fat dominated under all conditions in the sparrow. These data indicate fuel selection, at least in part, can be modulated at the level of the mitochondrial matrix when multiple substrates are present at saturating levels. As an increase in matrix oxidation-reduction potential has been linked to a suppression of fat oxidation and high ROS production, the high ETC activity relative to dehydrogenase activity in avian compared to mammalian mitochondria may result in lower matrix oxidation-reduction potential, allowing fatty acid oxidation to proceed while also resulting in low ROS production in vivo.
ContributorsKuzmiak, Sarah (Author) / Willis, Wayne T (Thesis advisor) / Mandarino, Lawrence (Committee member) / Sweazea, Karen (Committee member) / Harrison, Jon (Committee member) / Gadau, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
Critical care environments are complex in nature. Fluctuating team dynamics and the plethora of technology and equipment create unforeseen demands on clinicians. Such environments become chaotic very quickly due to the chronic exposure to unpredictable clusters of events. In order to cope with this complexity, clinicians tend to develop ad-hoc adaptations to function in an effective manner. It is these adaptations or "deviations" from expected behaviors that provide insight into the processes that shape the overall behavior of the complex system. The research described in this manuscript examines the cognitive basis of clinicians' adaptive mechanisms and presents a methodology for studying the same. Examining interactions in complex systems is difficult due to the disassociation between the nature of the environment and the tools available to analyze underlying processes. In this work, the use of a mixed methodology framework to study trauma critical care, a complex environment, is presented. The hybrid framework supplements existing methods of data collection (qualitative observations) with quantitative methods (use of electronic tags) to capture activities in the complex system. Quantitative models of activities (using Hidden Markov Modeling) and theoretical models of deviations were developed to support this mixed methodology framework. The quantitative activity models developed were tested with a set of fifteen simulated activities that represent workflow in trauma care. A mean recognition rate of 87.5% was obtained in automatically recognizing activities. Theoretical models, on the other hand, were developed using field observations of 30 trauma cases. The analysis of the classification schema (with substantial inter-rater reliability) and 161 deviations identified shows that expertise and role played by the clinician in the trauma team influences the nature of deviations made (p<0.01). The results shows that while expert clinicians deviate to innovate, deviations of novices often result in errors. Experts' flexibility and adaptiveness allow their deviations to generate innovative ideas, in particular when dynamic adjustments are required in complex situations. The findings suggest that while adherence to protocols and standards is important for novice practitioners to reduce medical errors and ensure patient safety, there is strong need for training novices in coping with complex situations as well.
ContributorsVankipuram, Mithra (Author) / Greenes, Robert A (Thesis advisor) / Patel, Vimla L. (Thesis advisor) / Petitti, Diana B. (Committee member) / Dinu, Valentin (Committee member) / Smith, Marshall L. (Committee member) / Arizona State University (Publisher)
Created2012
Description
This work involved the analysis of a public health system, and the design, development and deployment of enterprise informatics architecture, and sustainable community methods to address problems with the current public health system. Specifically, assessment of the Nationally Notifiable Disease Surveillance System (NNDSS) was instrumental in forming the design of the current implementation at the Southern Nevada Health District (SNHD). The result of the system deployment at SNHD was considered as a basis for projecting the practical application and benefits of an enterprise architecture. This approach has resulted in a sustainable platform to enhance the practice of public health by improving the quality and timeliness of data, effectiveness of an investigation, and reporting across the continuum.
ContributorsKriseman, Jeffrey Michael (Author) / Dinu, Valentin (Thesis advisor) / Greenes, Robert (Committee member) / Johnson, William (Committee member) / Arizona State University (Publisher)
Created2012
Description
Immunosignaturing is a technology that allows the humoral immune response to be observed through the binding of antibodies to random sequence peptides. The immunosignaturing microarray is based on complex mixtures of antibodies binding to arrays of random sequence peptides in a multiplexed fashion. There are computational and statistical challenges to the analysis of immunosignaturing data. The overall aim of my dissertation is to develop novel computational and statistical methods for immunosignaturing data to access its potential for diagnostics and drug discovery. Firstly, I discovered that a classification algorithm Naive Bayes which leverages the biological independence of the probes on our array in such a way as to gather more information outperforms other classification algorithms due to speed and accuracy. Secondly, using this classifier, I then tested the specificity and sensitivity of immunosignaturing platform for its ability to resolve four different diseases (pancreatic cancer, pancreatitis, type 2 diabetes and panIN) that target the same organ (pancreas). These diseases were separated with >90% specificity from controls and from each other. Thirdly, I observed that the immunosignature of type 2 diabetes and cardiovascular complications are unique, consistent, and reproducible and can be separated by 100% accuracy from controls. But when these two complications arise in the same person, the resultant immunosignature is quite different in that of individuals with only one disease. I developed a method to trace back from informative random peptides in disease signatures to the potential antigen(s). Hence, I built a decipher system to trace random peptides in type 1 diabetes immunosignature to known antigens. Immunosignaturing, unlike the ELISA, has the ability to not only detect the presence of response but also absence of response during a disease. I observed, not only higher but also lower peptides intensities can be mapped to antigens in type 1 diabetes. To study immunosignaturing potential for population diagnostics, I studied effect of age, gender and geographical location on immunosignaturing data. For its potential to be a health monitoring technology, I proposed a single metric Coefficient of Variation that has shown potential to change significantly when a person enters a disease state.
ContributorsKukreja, Muskan (Author) / Johnston, Stephen Albert (Thesis advisor) / Stafford, Phillip (Committee member) / Dinu, Valentin (Committee member) / Arizona State University (Publisher)
Created2012
Description
Here I present a phylogeographic study of at least six reproductively isolated lineages of harvester ants within the Pogonomyrmex barbatus and P. rugosus species group. The genetic and geographic relationships within this clade are complex: four of the identified lineages are divided into two pairs, and each pair has evolved under a mutualistic system that necessitates sympatry. These paired lineages are dependent upon one another because interlineage matings within each pair are the sole source of hybrid F1 workers; these workers build and sustain the colonies, facilitating the production of the reproductive caste, which results solely from intralineage fertilizations. This system of genetic caste determination (GCD) maintains genetic isolation among these closely related lineages, while simultaneously requiring co-expansion and emigration as their distributions have changed over time. Previous studies have also demonstrated that three of the four lineages displaying this unique genetic caste determination phenotype are of hybrid origin. Thus, reconstructing the phylogenetic and geographic history of this group allows us to evaluate past insights and plan future inquiries in a more complete historical biogeographic context. Using mitochondrial DNA sequences sampled across most of the morphospecies' ranges in the U.S. and Mexico, I employed several methods of phylogenetic and DNA sequence analysis, along with comparisons to geological, biogeographic, and phylogeographic studies throughout the sampled regions. These analyses on Pogonomyrmex harvester ants reveal a complex pattern of vicariance and dispersal that is largely concordant with models of late Miocene, Pliocene, and Pleistocene range shifts among various arid-adapted taxa in North America.
ContributorsMott, Brendon (Author) / Gadau, Juergen (Thesis advisor) / Fewell, Jennifer (Committee member) / Anderson, Kirk (Committee member) / Arizona State University (Publisher)
Created2012
Description
In social insect colonies, as with individual animals, the rates of biological processes scale with body size. The remarkable explanatory power of metabolic allometry in ecology and evolutionary biology derives from the great diversity of life exhibiting a nonlinear scaling pattern in which metabolic rates are not proportional to mass, but rather exhibit a hypometric relationship with body size. While one theory suggests that the supply of energy is a major physiological constraint, an alternative theory is that the demand for energy is regulated by behavior. The central hypothesis of this dissertation research is that increases in colony size reduce the proportion of individuals actively engaged in colony labor with consequences for energetic scaling at the whole-colony level of biological organization. A combination of methods from comparative physiology and animal behavior were developed to investigate scaling relationships in laboratory-reared colonies of the seed-harvester ant, Pogonomyrmex californicus. To determine metabolic rates, flow-through respirometry made it possible to directly measure the carbon dioxide production and oxygen consumption of whole colonies. By recording video of colony behavior, for which ants were individually paint-marked for identification, it was possible to reconstruct the communication networks through which information is transmitted throughout the colony. Whole colonies of P. californicus were found to exhibit a robust hypometric allometry in which mass-specific metabolic rates decrease with increasing colony size. The distribution of walking speeds also scaled with colony size so that larger colonies were composed of relatively more inactive ants than smaller colonies. If colonies were broken into random collections of workers, metabolic rates scaled isometrically, but when entire colonies were reduced in size while retaining functionality (queens, juveniles, workers), they continued to exhibit a metabolic hypometry. The communication networks in P. californicus colonies contain a high frequency of feed-forward interaction patterns consistent with those of complex regulatory systems. Furthermore, the scaling of these communication pathways with size is a plausible mechanism for the regulation of whole-colony metabolic scaling. The continued development of a network theory approach to integrating behavior and metabolism will reveal insights into the evolution of collective animal behavior, ecological dynamics, and social cohesion.
ContributorsWaters, James S., 1983- (Author) / Harrison, Jon F. (Thesis advisor) / Quinlan, Michael C. (Committee member) / Pratt, Stephen C. (Committee member) / Fewell, Jennifer H. (Committee member) / Gadau, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
Cuticular hydrocarbons (CHCs) play a crucial role in social insect recognition systems. In this study we investigated mate choice in the red harvester ant, Pogonomyrmex barbatus. In Phoenix, this species has two lineages, J1 and J2, which look identical, but are genetically isolated. In the genetic caste determination (GCD) system workers and queens are determined by their genotype (i.e., workers develop from interlineage crosses, queens from intralineage crosses). As such, J1 and J2 lineages are dependent on each other in order for colonies to produce both workers and reproductive queens. Given their genetic isolation and interdependence, we hypothesized that the CHCs of alate males and queens are affected by lineage, and that differences in the CHC profile are used for mate recognition. We tested these hypotheses by analyzing the lineage distributions of actively mating pairs (n=65), and compared them with the overall distribution of male and female sexuals (n=180). We additionally analyzed the five most abundant CHC compounds for 20 of the actively mating P. barbatus alate male and queen pairs to determine how variable the two lineages are between each sex. We found that mating pair distributions did not significantly differ from those expected under a random mating system (�2= 1.4349, P= 0.6973), however, CHC profiles did differ between J1 and J2 lineages and sexes for the five most abundant CHC compounds. Our results show that random mating is taking place in this population, however given the differences observed in CHC profiles, mate recognition could be taking place.
ContributorsTula Del Moral Testai, Pedro Rafael (Co-author) / Cash, Elizabeth (Co-author) / Gadau, Juergen (Thesis director) / Liebig, Juergen (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
I tested the hypothesis that in mature colonies of the seed harvester Pogonomyrmex californicus ant species, paired pleometrotic queens would produce workers more efficiently after a massive removal of their work force than haplometrotic queens, paired pleometrotic with haplometrotic queens, and single pleometrotic queens. I suggested that the paired pleometrotic queens would have an advantage of cooperating together in reproducing more workers quicker than the other conditions to make up for the lost workers. This would demonstrate a benefit that pleometrosis has over haplometrosis for mature colonies, which would explain why pleometrosis continues for P.californicus after colony foundation. After removing all but twenty workers for every colony, I took pictures and counted the emerging brood for 52 days. Analyses showed that the paired pleometrotic queens and the haplometrotic queens both grew at an equally efficient rate and the paired pleometrotic and haplometrotic queens growing the least efficiently. However, the results were not significant and did not support the hypothesis that paired pleometrotic queens recover from worker loss more proficiently than other social systems.
ContributorsFernandez, Marisa Raquel (Author) / Fewell, Jennifer (Thesis director) / Gadau, Juergen (Committee member) / Haney, Brian (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / Department of Psychology (Contributor)
Created2014-05
Description
Wolbachia is a genus of obligately intracellular bacterial endosymbionts of arthropods and nematodes, infecting up to 66% of all such species. In order to ensure its transmission, it may modify host reproduction by inducing one of four phenotypes: cytoplasmic incompatibility, feminization of genetic males, killing of male embryos, and induction of thelytokous parthenogenesis. This investigation was a characterization of the so-far unexamined Wolbachia infection of Pogonomyrmex ants. Five main questions were addressed: whether Wolbachia infection rates vary between North and South America, whether infection rates are dependent on host range, whether Wolbachia affects the caste determination of P. barbatus, whether infection rates in Pogonomyrmex are similar to those of other ants, and whether Wolbachia phylogeny parallels the phylogeny of its Pogonomyrmex hosts. Using PCR amplification of the wsp, ftsZ, and gatB loci, Wolbachia infections were detected in four of fifteen Pogonomyrmex species (26.7%), providing the first known evidence of Wolbachia infection in this genus. All infected species were from South America, specifically Argentina. Therefore, Wolbachia has no role in the caste determination of the North American species P. barbatus. Additionally, while it appears that the incidence of Wolbachia in Pogonomyrmex may be limited to South America, host range did not correlate with infection status. The incidence of Wolbachia in Pogonomyrmex as a whole was similar to that of invasive Solenopsis and Linepithema species, but not to Wasmannia auropunctata or Anoplolepis gracilipes, which retain Wolbachia infection in non-native locations. This suggests that there may be a parallel in Wolbachia infection spread in certain short-term models of species colonization and long-term models of genus radiation. Finally, there was no congruity between host and parasite phylogeny according to maximum likelihood analyses, necessarily due to horizontal transfer of Wolbachia between hosts and lateral gene transfer between Wolbachia strains within hosts.
ContributorsHarris, Alexandre Marm (Author) / Gadau, Juergen (Thesis director) / Martin, Thomas (Committee member) / Helmkampf, Martin Erik (Committee member) / Barrett, The Honors College (Contributor) / Computer Science and Engineering Program (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
DNA methylation, a subset of epigenetics, has been found to be a significant marker associated with variations in gene expression and activity across the entire human genome. As of now, however, there is little to no information about how DNA methylation varies between different tissues inside a singular person's body. By using research data from a preliminary study of lean and obese clinical subjects, this study attempts to put together a profile of the differences in DNA methylation that can be observed between two particular body tissues from this subject group: blood and skeletal muscle. This study allows us to start describing the changes that occur at the epigenetic level that influence how differently these two tissues operate, along with seeing how these tissues change between individuals of different weight classes, especially in the context of the development of symptoms of Type 2 Diabetes.
ContributorsRappazzo, Micah Gabriel (Author) / Coletta, Dawn (Thesis director) / Katsanos, Christos (Committee member) / Dinu, Valentin (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor) / Department of Psychology (Contributor)
Created2013-12