Structural and functional studies on the Yersinia ruckeri inverse autotransporters
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AbstractY. ruckeri is the causative agent of enteric redmouth disease (ERM), a serious infection of marine and freshwater fish. ERM is a global problem affecting aquaculture facilities worldwide. Losses caused by ERM can reach up to 75% of the fish stock. The amount of research on the pathogenicity of Y. ruckeri is still limited. In the presented thesis, Agnieszka Wrobel and coworkers discovered a new family of virulence factors related to the occurrence of the ERM. They have shown the presence, the domain architecture, the expression and the function of these virulence factors in various Y. ruckeri strains. The work presented in the thesis provides a new insight into Y. ruckeri pathogenesis and contributes to a better understanding of how Y. ruckeri survives in the aquatic environment. The thesis also provides the base for a new design of antibiofilm agents. Adhesins are surface-exposed virulence-related bacterial molecules involved in adherence to host cells and tissues. Adhesins are widely distributed in Gram-negative bacteria. The best studied examples are invasin and intimin, belonging to the inverse autotransporter family. Their presence, structure and role in Y. ruckeri strains are still unclear. This thesis shows that the inverse autotransporters are variably present in different Y. ruckeri strains and that their length also varies. Inverse autotransporters are proteins with a number of repetitive regions. These repetitive regions could only be properly identified using the third generation technology sequencing. These proteins are expressed at conditions relevant for pathogenesis and are exposed at the cell surface. They play a role in biofilm formation and pathogenesis. Finally, this thesis includes a plasmid sequence referred to as pYR4 found in a highly pathogenic Y. ruckeri NVH_3758 strain. This plasmid encodes type IV pili and conjugation system and can possibly contribute to Y. ruckeri virulence.
List of papers
|Paper I: Wrobel A., Ottoni C., Leo JC., Gulla S., Linke D. The repeat structure of two paralogous genes, Yersinia ruckeri invasin (yrInv) and a “Y. ruckeri invasin-like molecule”, (yrIlm) sheds light on the evolution of adhesive capacities of a fish pathogen. 2017. Journal of Structural Biology, 201(2): 171-183. DOI: 10.1016/j.jsb.2017.08.008 The article is included in the thesis. Also available at https://doi.org/10.1016/j.jsb.2017.08.008|
|Paper II: Wrobel A., Ottoni C., Leo JC., Linke D. pYR4 from a Norwegian isolate of Y. ruckeri is a putative virulence plasmid encoding both a type IV pilus and a type IV secretion system. 2018. Frontiers in Cellular and Infection Microbiology, 8(373): 1-14. DOI: fcimb.2018.00373 The article is included in the thesis. Also available in DUO http://hdl.handle.net/10852/66637|
|Paper III: Wrobel A., Liskiewicz K., Saragliadis A., Schneider K., Leo JC., Arenas J., Linke D. Y. ruckeri NVH_3758 inverse autotransporters contribute to biofilm formation. Manuscript. To be published. The paper is not available in DUO awaiting publishing.|