Abstract
Strongyloides is an important gastrointestinal parasite, affecting 600 million people world-wide. It also serves as a valuable model for the study of other parasitic nematodes, due to its unique life cycle, which has genetically identical parasitic and free-living generations. This renders Strongyloides exceptionally well-suited for exploring the molecular basis of parasitism, by enabling direct comparisons between these life cycle stages. From previous studies, we know that genes are differentially expressed between life cycle stages, including parasitic and free-living females. Therefore, their identical genomes are likely transcriptionally regulated, resulting in changing transcriptomes. However, how these genes are regulated remains unknown and information on UTR regions or alternative splicing in Strongyloides is not available, despite its importance in gene regulation. There are also many unresolved questions about gene expression in parasites and their environment: Are genes post-transcriptionally regulated in nematodes to aid adaption to their changing environment? And how are genes regulated in response to environmental stresses?This thesis focuses on three different aspects of gene regulation: Chapter 2: the expression of sRNAs and their regulation of genes in S. venezuelensis, in which we explore a novel sRNA family involved in reproduction; Chapter 3: long-read transcriptomics of five life cycle stages, used to identify novel transcripts and annotate UTR regions in S. ratti and Chapter 4: gene expression changes of S. ratti exposed to a naturally occurring nematophagous fungus Arthrobotrys oligospora, compared to the free-living nematode Caenorhabditis elegans.
The insights gained from this thesis not only improve our understanding of Strongyloides transcriptomics, but also offer novel perspectives that will inform further research into reproductive gene regulation strategies, the impact of non-coding region variation between life cycle stages and previously undescribed interactions of Strongyloides and environmental fungal stresses.
| Date of Award | 21 Feb 2024 |
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| Original language | English |
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| Supervisor | Vicky Hunt (Supervisor) & Maisem Laabei (Supervisor) |