Wolbachia is a maternally transmitted intracellular bacterium estimated to infect 40% of insect species. Wolbachia manipulates the host’s reproduction to facilitate its own spread in nature. Transfection of Wolbachia strains from Drosophila melanogaster into mosquitoes can reduce the transmission of Dengue, Chikungunya, Zika and certain strains of the malaria parasite. Mosquitoes transmit these diseases because they require a blood meal to support egg production. Since every year approximately 1 million people die from mosquito-transmitted pathogens, the mosquito ovary can be considered one of the most dangerous organs to mankind. Nevertheless, little is known about early development of a mosquito egg, including the presence of active germline stem cells. In this thesis, through dual pulse experiments, we identify two cells that reside permanently at the anterior tip of the germarium and are actively dividing. Additional antibody labeling, presence of spectrosomes, 3D confocal reconstruction and scanning electron microscopy experiments confirm these cells as the germline stem cells and identify their respective niche. We also identified the somatic stem cells which give rise to the follicular epithelium, a cell type necessary for egg development. Characterization of Wolbachia infected mosquito ovaries displayed high density in the germline, but low density in the surrounding somatic cells. High Wolbachia densities correlate with reduced pathogen transmission. Host autophagy possibly affects Wolbachia intracellular density. Autophagy is an intracellular degradation pathway involved in innate immunity against bacteria and viruses. The literature suggests that autophagy positively regulates Wolbachia in the germline and negatively in somatic cells. We utilized genetic manipulations of several autophagy genes to determine that a selective form of autophagy in somatic cells negatively regulates Wolbachia, while a non-selective form positively regulates Wolbachia in the germline. Furthermore, we find that Wolbachia effectors can regulate Wolbachia density through the autophagy pathway. In the germline we utilize global metabolomics of autophagy mutants to identify candidate pathways that can positively influence Wolbachia density. These results provide novel insights into the mechanisms of Wolbachia – host autophagy interactions. / 2022-03-17T00:00:00Z
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/39876 |
| Date | 18 March 2020 |
| Creators | Deehan, Mark Anthony |
| Contributors | Frydman, Horacio M. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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