Matching Items (13)
Filtering by
- All Subjects: Biology
Description
There is increasing evidence that ovarian status influcences behavioral phenotype in workers of the honey bee Apis mellifera. Honey bee workers demonstrate a complex division of labor. Young workers perform in-hive tasks (e.g. brood care), while older bees perform outside tasks (e.g. foraging for food). This age correlated division of labor is known as temporal polyethism. Foragers demonstrate further division of labor with some bees biasing collection towards protein (pollen) and others towards carbohydrates (nectar). The Reproductive Ground-plan Hypothesis proposes that the ovary plays a regulatory role in foraging division of labor. European honey bee workers that have been selectively bred to store larger amounts of pollen (High strain) also have a higher number of ovarioles per ovary than workers from strains bred to store less pollen (Low strain). High strain bees also initiate foraging earlier than Low strain bees. The relationship between ovariole number and foraging behavior is also observed in wild-type Apis mellifera and Apis cerana: pollen-biased foragers have more ovarioles than nectar-biased foragers. In my first study, I investigated the pre-foraging behavioral patterns of the High and Low strain bees. I found that High strain bees progress through the temporal polyethism at a faster rate than Low strain bees. To ensure that the observed relationship between the ovary and foraging bias is not due to associated separate genes for ovary size and foraging behavior, I investigated foraging behavior of African-European backcross bees. The backcross breeding program was designed to break potential gene associations. The results from this study demonstrated the relationship between the ovary and foraging behavior, supporting the proposed causal linkage between reproductive development and behavioral phenotype. The final study was designed to elucidate a regulatory mechanism that links ovariole number with sucrose sensitivity, and loading decisions. I measured ovariole number, sucrose sensitivity and sucrose solution load size using a rate-controlled sucrose delivery system. I found an interaction effect between ovariole number and sucrose sensitivity for sucrose solution load size. This suggests that the ovary impacts carbohydrate collection through modulation of sucrose sensitivity. Because nectar and pollen collection are not independent, this would also impact protein collection.
ContributorsSiegel, Adam J (Author) / Page, Jr., Robert E (Thesis advisor) / Hamilton, Andrew L. (Committee member) / Brent, Colin S (Committee member) / Amdam, Gro V (Committee member) / McGraw, Kevin J. (Committee member) / Arizona State University (Publisher)
Created2011
Description
A notable feature of advanced eusocial insect groups is a division of labor within the sterile worker caste. However, the physiological aspects underlying the differentiation of behavioral phenotypes are poorly understood in one of the most successful social taxa, the ants. By starting to understand the foundations on which social behaviors are built, it also becomes possible to better evaluate hypothetical explanations regarding the mechanisms behind the evolution of insect eusociality, such as the argument that the reproductive regulatory infrastructure of solitary ancestors was co-opted and modified to produce distinct castes. This dissertation provides new information regarding the internal factors that could underlie the division of labor observed in both founding queens and workers of Pogonomyrmex californicus ants, and shows that changes in task performance are correlated with differences in reproductive physiology in both castes. In queens and workers, foraging behavior is linked to elevated levels of the reproductively-associated juvenile hormone (JH), and, in workers, this behavioral change is accompanied by depressed levels of ecdysteroid hormones. In both castes, the transition to foraging is also associated with reduced ovarian activity. Further investigation shows that queens remain behaviorally plastic, even after worker emergence, but the association between JH and behavioral bias remains the same, suggesting that this hormone is an important component of behavioral development in these ants. In addition to these reproductive factors, treatment with an inhibitor of the nutrient-sensing pathway Target of Rapamycin (TOR) also causes queens to become biased towards foraging, suggesting an additional sensory component that could play an important role in division of labor. Overall, this work provides novel identification of the possible regulators behind ant division of labor, and suggests how reproductive physiology could play an important role in the evolution and regulation of non-reproductive social behaviors.
ContributorsDolezal, Adam G (Author) / Amdam, Gro V (Thesis advisor) / Brent, Colin S. (Committee member) / Gadau, Juergen (Committee member) / Hoelldobler, Bert (Committee member) / Liebig, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
Pathway analysis helps researchers gain insight into the biology behind gene expression-based data. By applying this data to known biological pathways, we can learn about mutations or other changes in cellular function, such as those seen in cancer. There are many tools that can be used to analyze pathways; however, it can be difficult to find and learn about the which tool is optimal for use in a certain experiment. This thesis aims to comprehensively review four tools, Cytoscape, PaxtoolsR, PathOlogist, and Reactome, and their role in pathway analysis. This is done by applying a known microarray data set to each tool and testing their different functions. The functions of these programs will then be analyzed to determine their roles in learning about biology and assisting new researchers with their experiments. It was found that each tools holds a very unique and important role in pathway analysis. Visualization pathways have the role of exploring individual pathways and interpreting genomic results. Quantification pathways use statistical tests to determine pathway significance. Together one can find pathways of interest and then explore areas of interest.
ContributorsRehling, Thomas Evan (Author) / Buetow, Kenneth (Thesis director) / Wilson, Melissa (Committee member) / School of Life Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Parabasalia is a phylum of flagellated protists with a large range of cell sizes, spanning from as little as 7 µm in length (e.g. Pentatrichomonas hominis) to well over 300 µm (e.g. Pseudotrichonympha grassii). Many Parabasalia are associated with animals in mutualistic, parasitic, or commensal relationships. The largest Parabasalia species are obligate mutualists of termites, which help to digest lignocellulose. While the specific digestive roles of different protist species are mostly unknown, Parabasalia with different cell sizes are known to inhabit different regions of the termite hindgut. It is currently unclear whether these size differences are driven by selection or drift, but it is well known that cell size correlates with genome size in eukaryotes. Therefore, in order to gain insight into possible selection pressures or mechanisms for cell size increase, genome sizes were estimated for the five Parabasalia species that inhabit the hindgut of Coptotermes formosanus Shiraki. The cell volumes and C-values for the five protist species are 89,190 µm3 and 147 pg in Pseudotrichonympha grassii, 26,679 µm3 and 56 pg in Holomastigotoides hartmanni, 8,985 µm3 and 29 pg in Holomastigotoides minor, 1,996 µm3 and 12 pg in Cononympha leidyi , and 386 µm3 and 6 pg in Cononympha koidzumii. The positive correlation between genome size and cell size was maintained in this group (R2 = 0.76). These genome sizes are much larger than the previously estimated genome sizes of non-termite associated Parabasalia, which spanned 2-fold ranging from 0.088 pg (in Tetratrichomonas gallinarum) to 0.181 pg (in Trichomonas foetus). With these new estimates, the range now spans over 1,500-fold from 0.088 pg to 147 pg in P. grassii, implying potential differences in the level of selective pressures for genome size in termite-associated Parabasalia compared to other protists.
ContributorsMontoya, Samantha (Author) / Gile, Gillian (Thesis advisor) / Wideman, Jeremy (Committee member) / Chouvenc, Thomas (Committee member) / Arizona State University (Publisher)
Created2021
Description
Predatory bacteria are a guild of heterotrophs that feed directly on other living bacteria. They belong to several bacterial lineages that evolved this mode of life independently and occur in many microbiomes and environments. Current knowledge of predatory bacteria is based on culture studies and simple detection in natural systems. The ecological consequences of their activity, unlike those of other populational loss factors like viral infection or grazing by protists, are yet to be assessed. During large-scale cultivation of biological soil crusts intended for arid soil rehabilitation, episodes of catastrophic failure were observed in cyanobacterial growth that could be ascribed to the action of an unknown predatory bacterium using bioassays. This predatory bacterium was also present in natural biocrust communities, where it formed clearings (plaques) up to 9 cm in diameter that were visible to the naked eye. Enrichment cultivation and purification by cell-sorting were used to obtain co-cultures of the predator with its cyanobacterial prey, as well as to identify and characterize it genomically, physiologically and ultrastructurally. A Bacteroidetes bacterium, unrelated to any known isolate at the family level, it is endobiotic, non-motile, obligately predatory, displays a complex life cycle and very unusual ultrastructure. Extracellular propagules are small (0.8-1.0 µm) Gram-negative cocci with internal two-membrane-bound compartmentalization. These gain entry to the prey likely using a suite of hydrolytic enzymes, localizing to the cyanobacterial cytoplasm, where growth begins into non-compartmentalized pseudofilaments that undergo secretion of vesicles and simultaneous multiple division to yield new propagules. I formally describe it as Candidatus Cyanoraptor togatus, hereafter Cyanoraptor. Its prey range is restricted to biocrust-forming, filamentous, non-heterocystous, gliding, bundle-making cyanobacteria. Molecular meta-analyses showed its worldwide distribution in biocrusts. Biogeochemical analyses of Cyanoraptor plaques revealed that it causes a complete loss of primary productivity, and significant decreases in other biocrusts properties such as water-retention and dust-trapping capacity. Extensive field surveys in the US Southwest revealed its ubiquity and its dispersal-limited, aggregated spatial distribution and incidence. Overall, its activity reduces biocrust productivity by 10% at the ecosystem scale. My research points to predatory bacteria as a significant, but overlooked, ecological force in shaping soil microbiomes.
ContributorsBethany Rakes, Julie Ann (Author) / Garcia-Pichel, Ferran (Thesis advisor) / Gile, Gillian (Committee member) / Cao, Huansheng (Committee member) / Jacobs, Bertram (Committee member) / Arizona State University (Publisher)
Created2022
Description
While only the sixth most common cancer globally, liver cancer is the third most deadly. Despite the importance of accurate diagnosis and effective treatment, standard diagnostic tests for most solid organ neoplasms are not required for the most common type of liver cancer, Hepatocellular Carcinoma (HCC). In addition, major discrepancies in the practices currently in place limits the ability to develop more precise oncological treatment and prognosis. This study aimed to identify biomarkers, with potential to more accurately diagnose how far cancer has advanced within a patient and determine prognosis. It is the hope that pathways provided by this study form the basis for future research into more standardized practices and potential treatment based on specific affected biological processes. The PathOlogist tool was utilized to calculate activity metrics for 1,324 biological pathways in 374 The Cancer Genome Atlas (TCGA) hepatocellular carcinoma donors. Further statistical analysis was done on two datasets, formed to identify grade or stage at time of diagnosis for the activity levels calculated by PathOlogist. The datasets were evaluated individually. Based on the variance and normality of each pathway’s activity levels in the respective data sets analysis of variance, Tukey-Kramer, Kruskal-Wallis, and Mann-Whitney-Wilcox tests were performed, when appropriate, to determine any statistically significant differences in pathway activity levels. Pathways were identified in both stage and grade data analyses that show significant differences in activity levels across designation. While some overlap is seen, there was a significant number of pathways unique to either stage or grade. These pathways are known to affect the cell cycle, cellular transport, disease, immune system, and metabolism regulation.
The biological pathways named by this research depict prospective biomarkers for progression of hepatocellular carcinoma per subdivision within both stage and grade. These findings may be instrumental to new methods of early and more accurate diagnosis. The distinct differences in identified pathways in grade and stage illustrate the need for these new methods to not only look at stage but also grade when determining prognosis. Furthermore, the pathways identified herein have potential to aid in the development of targeted treatment based on the affected biological processes.
ContributorsGarrison, Alyssa Cameron (Author) / Buetow, Kenneth (Thesis advisor) / Hinde, Katie (Committee member) / Wilson, Melissa (Committee member) / Arizona State University (Publisher)
Created2022
Description
In many social groups, reproduction is shared between group members, whocompete for position in the social hierarchy for reproductive dominance. This
reproductive conflict can lead to different means of enforcing reproductive differences,
such as dominance displays or limited control of social hierarchy through antagonistic
encounters. In eusocial insects, archetypal colonies contain a single, singly-mated fertile
queen, such that no reproductive conflict exists within a colony. However, many eusocial
insects deviate from this archetype and have multiply-mated queens (polyandry), multiple
queens in a single colony (polygyny), or both. In these cases, reproductive conflict exists
between the matrilines and patrilines represented in a colony, specifically over the
production of sexual offspring. A possible outcome of reproductive conflict may be the
emergence of cheating lineages, which favor the production of sexual offspring, taking
advantage of the worker force produced by nestmate queens and/or patrilines. In extreme
examples, inquiline social parasites may be an evolutionary consequence of reproductive
conflict between nestmate queens. Inquiline social parasitism is a type of social
parasitism that is usually defined by a partial or total loss of the worker caste, and the
“infiltration” of host colonies to take advantage of the host worker force for reproduction.
It has been hypothesized that these inquiline social parasites evolve through the
speciation of cheating queen lineages from within their incipient host species. This “intra-
specific” origin model involves a foundational hypothesis that the common ancestor of
host and parasite (and thus, putatively, the host at the time of speciation) should be
functionally polygynous, and that parasitism evolves as a “resolution” of reproductive
conflict in colonies. In this dissertation, I investigate the hypothesized role of polygyny in the evolution of inquiline social parasites. I use molecular ecology and statistical
approaches to validate the role of polygyny in the evolution of some inquiline social
parasites. I further discuss potential mechanisms for the evolution and speciation of social
parasites, and discuss future directions to elucidate these mechanisms.
ContributorsDahan, Romain Arvid (Author) / Rabeling, Christian (Thesis advisor) / Amdam, Gro V (Committee member) / Fewell, Jennifer H (Committee member) / Pratt, Stephen C (Committee member) / Rüppell, Olav (Committee member) / Arizona State University (Publisher)
Created2021
Description
To combat the global antimalarial resistance crisis effective resistance management strategies are needed. To do so, I need to gain a better understanding of the ecological interactions occurring within malaria infections. Despite the importance of the complex interplay among co-infecting strains, our current knowledge and empirical data of within-host diversity and malaria disease dynamics is limited. In this thesis, I explore the multifaceted dynamics of malaria infections through an ecological lens. My overall research question is: "How do ecological interactions, including niche complementarity, competition dynamics, and the cost of resistance, shape the outcomes of malaria infections, and what implications does this have on understanding and improving resistance management strategies?” In Chapter II, titled “Niche Complementarity in Malaria Infections” I demonstrate that ecological principles are observed in malarial infections by experimentally manipulating the biodiversity of rodent malaria P. chabaudi infections. I observed that some parasites experienced competitive suppression, others experienced competitive facilitation, while others were not impacted. Next, in Chapter III, titled “Determining the Differential Impact of Competition Between Genetically Distinct Plasmodium falciparum Strains” I investigate the differential effect of competition among six genetically distinct strains. The impact of competition varied between strain combinations, and both suppression and facilitation were observed, but most pairings had no competitive interactions. Lastly, in Chapter IV, titled “Assessing Fitness Costs in Malaria Parasites: A Comprehensive Review and Implications for Drug Resistance Management”, I summarize where the field currently stands and what evidence there is for the presence of a fitness cost, or lack thereof, and I highlight the current gaps in knowledge. I found that evidence from field, in vitro, and animal models are overall suggestive of the presence of a fitness cost, however, these costs were not always found. Amid the current focus on malaria eradication, it is crucial to understand the impact of biodiversity on disease severity. By incorporating an ecological approach to infectious disease systems, I can gain insights on within-host interactions and how they impact parasite fitness and transmissibility.
ContributorsSegovia, Xyonane (Author) / Huijben, Silvie (Thesis advisor) / Bean, Heather (Committee member) / Gile, Gillian (Committee member) / Hogue, Ian (Committee member) / Lake, Douglas (Committee member) / Arizona State University (Publisher)
Created2024
Description
Mycobacterium leprae, the causative agent of Hansen’s disease (leprosy), has plagued humans and other animal species for millennia and remains of concern to public health throughout the world today. Recent research into the expanded use of medical tissues preserved as formalin-fixed, paraffin-embedded samples (FFPE), opened the door for the study of M. leprae DNA from preserved skin samples. However, problems persist with damage to the DNA including fragmentation and cross linkage. This study evaluated two methods commonly used for the recovery of host DNA from FFPE samples for their efficacy in extracting pathogen DNA (hot alkaline lysis protocol and QIAGEN QIAamp FFPE DNA kit). Twenty FFPE skin samples collected from 1995-2015 from human subjects in the Pacific Islands suffering from M. leprae infection, each exhibiting a range of bacillary loads, were analyzed to determine which extraction method was most successful in terms of ability to consistently yield reliable, robust traces of M. leprae infection. This study further examined these samples to understand the phylogeny of leprosy in the region, where gaps in the evolutionary history of M. leprae persist. DNA recovery from paired samples was similar using either method. However, by extending the incubation time of post-paraffin removal sample lysis, both protocols were more likely to yield positive traces of M. leprae, with this enhancement being especially evident in paucibacillary samples with low bacterial presence. The qPCR assay findings suggest that the hot alkaline procedure is most likely to yield positive identification of infection in these traditionally challenging samples.
ContributorsKing, Felicia Clarice (Author) / Stone, Anne (Thesis advisor) / Wilson, Melissa (Committee member) / Buetow, Ken (Committee member) / Arizona State University (Publisher)
Created2023
Description
In most diploid cells, autosomal genes are equally expressed from the paternal and maternal alleles resulting in biallelic expression. However, as an exception, there exists a small number of genes that show a pattern of monoallelic or biased-allele expression based on the allele’s parent-of-origin. This phenomenon is termed genomic imprinting and is an evolutionary paradox. The best explanation for imprinting is David Haig's kinship theory, which hypothesizes that monoallelic gene expression is largely the result of evolutionary conflict between males and females over maternal involvement in their offspring. One previous RNAseq study has investigated the presence of parent-of-origin effects, or imprinting, in the parasitic jewel wasp Nasonia vitripennis (N. vitripennis) and its sister species Nasonia giraulti (N. giraulti) to test the predictions of kinship theory in a non-eusocial species for comparison to a eusocial one. In order to continue to tease apart the connection between social and eusocial Hymenoptera, this study proposed a similar RNAseq study that attempted to reproduce these results in unique samples of reciprocal F1 Nasonia hybrids. Building a pseudo N. giraulti reference genome, differences were observed when aligning RNAseq reads to a N. vitripennis reference genome compared to aligning reads to a pseudo N. giraulti reference. As well, no evidence for parent-of-origin or imprinting patterns in adult Nasonia were found. These results demonstrated a species-of-origin effect. Importantly, the study continued to build a repository of support with the aim to elucidate the mechanisms behind imprinting in an excellent epigenetic model species, as it can also help with understanding the phenomenon of imprinting in complex human diseases.
ContributorsUnderwood, Avery Elizabeth (Author) / Wilson, Melissa (Thesis advisor) / Buetow, Kenneth (Committee member) / Gile, Gillian (Committee member) / Arizona State University (Publisher)
Created2019