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Description
The brain is considered the crux of identity, yet human behavior may be influenced by bacteria in gut microbiomes. Honeybees can exchange bacteria through their many social behaviors, making their microbiomes, and the effect they have on honeybee behavior, of interest. There is recent evidence suggesting the presence of bacteria existing in human brains, which can be investigated in honeybee brains due to their well-documented structure. The purpose of this study is to establish if lipopolysaccharide—a molecule on bacteria membranes—is present in the honeybee brain and if it colocalizes with vitellogenin—an immune mediator. Additionally, this study also seeks to establish the efficacy of embedding tissue samples in resin and performing immunohistochemistry for vitellogenin and lipopolysaccharide on sections.
ContributorsStrange, Amalie Sofie (Co-author) / Strange, Amalie (Co-author) / Amdam, Gro (Thesis director) / Baluch, Page (Committee member) / School of International Letters and Cultures (Contributor) / School of Life Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Division of labor is a hallmark for social insects and is closely related to honey bee morphology and physiology. Vitellogenin (Vg), a precursor protein in insect egg yolk, has several known functions apart from serving as a nutrient source for developing eggs. Vg is a component in the royal jelly produced in the hypopharyngeal glands (HPG) of worker bees which is used to feed both the developing brood and the queen. The HPG is closely associated with divisions of labor as the peak in its development corresponds with the nursing behavior. Independent of the connection between Vg and the HPG, Vg has been seen to play a fundamental role in divisions of labor by affecting worker gustatory responses, age of onset of foraging, and foraging preferences. Similar to Vg, the number of ovarioles in worker ovaries is also associated with division of labor as bees with more ovarioles tend to finish tasks in the hive and become foragers faster. This experiment aims to connect HPGs, ovaries, and Vg by proposing a link between them in the form of ecdysone (20E). 20E is a hormone produced by the ovaries and is linked to ovary development and Vg by tyramine titers. By treating young emerged bees with ecdysone and measuring HPG and ovary development over a trial period, this experiment seeks to determine whether 20E affects division of labor through Vg. We found that though the stress of injection caused a significant decrease in development of both the ovaries and HPG, there was no discernable effect of 20E on either of these organs.
ContributorsChin, Elijah Seth (Author) / Wang, Ying (Thesis director) / Page, Robert (Committee member) / Cook, Chelsea (Committee member) / School of Molecular Sciences (Contributor) / W. P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Many animals possess a blood-brain barrier, which is a layer of cells that restricts the passage of molecules into the central nervous system. The primary function of the blood-brain barrier is to preserve ionic homeostasis within the brain; however, it is also responsible for selectively importing an array of nutritional and signaling molecules to support brain function and for exporting metabolic waste. Across the species in which it has been studied, the structure and function of the blood-brain barrier dynamically regulates the interaction between the brain and peripheral physiological systems. Honeybee (Apis mellifera) workers are a firmly established neurobiological model which can be utilized to answer questions about the physiological and environmental mechanisms that regulate central nervous system health and behavior. It is likely that the honeybee blood-brain barrier plays an important role mediating the interactions between the brain and its environment, however, the blood-brain barrier is largely unconsidered in the realm of honeybee neurobiological research. In this dissertation, I provide the first in depth characterizations of the structure and function of the honeybee blood-brain barrier. First, I characterized the ultrastructural organization of the honeybee blood-brain barrier. The results of this study demonstrate its structural heterogeneity, including how this heterogeneity compares between two age groups. Next, I assessed two dimensions of blood-brain barrier permeability among three honeybee age groups and among honeybees exposed to varying amounts of infestation with the parasitic mite Varroa destructor. This study demonstrated that paracellular permeability has greater resilience than transcellular permeability, the latter of which is particularly increased by a high parasitic load. Finally, I developed a novel technique combining stable isotope labelling and Nanoscale Secondary Ion Mass Spectrometry (NanoSIMS) to demonstrate that the large, pro-social protein vitellogenin is able to cross the honeybee blood-brain barrier into the brain. Together, these studies represent the first in-depth analysis of the honeybee blood-brain barrier, establishing new directions for understanding the regulation of honeybee health, disease, and behavior.
ContributorsQuigley, Tyler (Author) / Amdam, Gro V. (Thesis advisor) / Bose, Maitrayee (Committee member) / Newbern, Jason (Committee member) / Bimonte-Nelson, Heather (Committee member) / Oland, Lynne (Committee member) / Arizona State University (Publisher)
Created2024