Matching Items (3)
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
Skeletal muscle can intrinsically repair itself in response to injury. This repair process has been shown to be mediated through signaling of the innate immune system. The immune response caused during repair helps to clear away debris in damage and promotes the activation and proliferation of muscle stem cells (MuSCs) that will repair the damage muscle. Dysregulation of this inflammation leads to fibrosis and decreased efficacy of the repair process. Despite the requirement of inflammatory signaling during muscle repair, muscle’s contribution during inflammation as only recently started to be explored. The objective of this dissertation is to assess the contribution of muscle in the early inflammatory response during repair as well attempting to modulate this inflammation during disease to ameliorate disease pathology in a model of Duchenne’s muscular dystrophy. I tested the hypotheses that 1) muscle is an active participant in the early inflammatory response, 2) the transcription factor Mohawk (Mkx) is a regulator of the early inflammatory response and, 3) If this inflammation can be modulated with a virally derived serine protease inhibitor in a model of muscle disrepair and chronic inflammation. I found that muscle is actively participating in the establishment early inflammation in repair through the production of chemokines used to promote infiltration of immune cells. As well as the identification of a new muscle subtype that produces more chemokines compared to the average MuSC and upregulated genes in the Interferon signaling pathway. I also discovered that presence of this muscle subtype is linked to the expression of Mkx. In Mkx null mice this population is not present, and these cells are deficient in chemokine expression compared to WT mice. I subsequently found that, using the myxomavirus derived serine protease inhibitor, Serp-1 I was able to modulate the chronic inflammation that is common in those affected with Duchenne’s muscular dystrophy (DMD) utilizing a high-fidelity mouse model of the disease. The result of this dissertation provides an expanded role for muscle in inflammation and gives a potential new class of therapeutics to be used in disease associated with chronic inflammation.
ContributorsAndre, Alex (Author) / Rawls, Alan (Thesis advisor) / Wilson-Rawls, Jeanne (Committee member) / Kusumi, Kenro (Committee member) / Lake, Doug (Committee member) / Chang, Yung (Committee member) / Arizona State University (Publisher)
Created2022
Description
Vitellogenin (Vg) is an ancient and highly conserved multifunctional protein. It is primarily known for its role in egg-yolk formation but also serves functions pertaining to immunity, longevity, nutrient storage, and oxidative stress relief. In the honey bee (Apis mellifera), Vg has evolved still further to include important social functions that are critical to the maintenance and proliferation of colonies. Here, Vg is used to synthesize royal jelly, a glandular secretion produced by a subset of the worker caste that is fed to the queen and young larvae and which is essential for caste development and social immunity. Moreover, Vg in the worker caste sets the pace of their behavioral development as they transition between different tasks throughout their life. In this dissertation, I make several new discoveries about Vg functionality. First, I uncover a colony-level immune pathway in bees that uses royal jelly as a vehicle to transfer pathogen fragments between nestmates. Second, I show that Vg is localized and expressed in the honey bee digestive tract and suggest possible immunological functions it may be performing there. Finally, I show that Vg enters to nucleus and binds to deoxyribonucleic acid (DNA), acting as a potential transcription factor to regulate expression of many genes pertaining to behavior, metabolism, and signal transduction pathways. These findings represent a significant advance in the understanding of Vg functionality and honey bee biology, and set the stage for many future avenues of research.
ContributorsHarwood, Gyan (Author) / Amdam, Gro V (Thesis advisor) / Kusumi, Kenro (Committee member) / Rabeling, Christian (Committee member) / Chang, Yung (Committee member) / Arizona State University (Publisher)
Created2019