| dc.description.abstract | Viruses are in a unique position to affect the ecology of many organisms, due to their sheer numbers and diversity. Although traditionally considered pathogens, viruses can engage in more complex and mutualistic associations with their hosts. Given the large diversity and abundance of prokaryotes, viruses infecting bacteria (referred to as bacteriophages), are particularly diverse, and have been shown to engage in interesting relationships with their host. Bacteriophages found in endosymbiotic bacteria (i.e. those that live inside another organism), represent interesting tri-partite interactions that have not been recently investigated in the mollicute Spiroplasma bacterium, as compared to other endosymbionts such as Wolbachia. Due to the many phenotypes associated with the presence of bacteriophage in endosymbionts, Spiroplasma bacteriophages can potentially be of physiological importance to the Spiroplasma-host interactions. To shed light on this neglected research area, the first chapter of this thesis is a review focused on double-stranded DNA bacteriophages of Spiroplasma. The second chapter used a bioinformatics approach to seek potential interactions between Spiroplasma and bacteriophages, by searching for putative prophage sequences within the publicly available Spiroplasma genome sequences. Of the available genomes, only S. citri, S. kunkelli and S. Chic contained putative prophage regions in their genomes. The putative regions had high homology to each other. The third chapter attempted to break a several-decade hiatus of research on bacteriophage of Drosophila-associated Spiroplasma. Putative phage particles were isolated from the male-killing Spiroplasma Poulson NSRO bacterium hosted in Drosophila melanogaster flies. DNA of such particles was extracted and sequenced with Nanopore (long read) technology. Two putative phage draft contigs, NSROP-1 and NSROP-2, were assembled and bioinformatically annotated. The draft contigs were further characterized using homology found in a sister Spiroplasma strain. | en |
