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Selected Publication:

Type of publication: PhD Thesis
Type of document:

Year: 2014

Authors: Ondrovics, Martina

Title: Unravelling the moulting process in Oesophagostomum dentatum with -omics technologies.

Source: PhD-Arbeit, Vet. Med. Univ. Wien, pp. 53.


Advisor(s):

Joachim Anja

Vetmed Research Units:
Institute of Parasitology


Graduation date: 30.04.15


Abstract:
Parasitic nematodes are of major socio-economic impact worldwide, as they represent significant pathogens of humans and animals and impose a substantial economic and public health burden. Widespread and increasing anthelmintic resistance has stimulated fundamental research, since a better understanding of pivotal developmental processes is imperative for designing alternative intervention and control strategies against these parasites. Biological pathways in nematodes might provide new anthelmintic targets. Ecdysis (moulting of the cuticle) constitutes a critical developmental process which is absent from the host and might provide a new target. Using an integrative approach, by combining in vitro assays with transcriptomic, proteomic and bioinformatic analyses, the present thesis aimed at elucidating the in vitro moulting process of the porcine nodule worm Oesophagostomum dentatum, a model organism for parasitic nematodes of socio-economic importance. Molecules involved in the in vitro moult from third-stage larvae (L3s) to fourth-stage larvae of O. dentatum were investigated by comparing the proteomic profile of a moulting-inhibited larval phenotype with that of control larvae by two-dimensional (2D) gel electrophoresis. Additionally, the in vitro exsheathment was targeted by employing a newly established filter-based technique and O. dentatum L3s before, during and after exsheathment were compared by 2D difference gel electrophoresis. Exsheathment represents the final and completing step of the moulting process and also marks the transition from the free-living to the parasitic life style in strongylid nematodes. Twenty-eight proteins differentially expressed in moulting-inhibited L3s compared to control larvae and/or over-expressed in L3s during exsheathment, but not before or after this transition, were detected. Subsequent mass spectrometric and bioinformatic analysis revealed an involvement of these proteins in energy metabolism, stress response and host-pathogen interactions, structure and motility, signalling and interaction and/or development and growth. Moreover, this study of the moulting process in O. dentatum showed the involvement of proteins in moulting in related nematode species (e.g. peptidyl-prolyl cis-transisomerase, cuticlin-1, intermediate filament protein B and tropomyosin), affirmed previous findings of proteins with predicted functions during nematode moult (e.g. fructose-bisphosphate aldolase, propionyl-CoA carboxylase and phosphoenolpyruvate carboxykinase [GTP]) and suggested new molecules to be crucial for moulting/exsheathment in O. dentatum (e.g. aspartyl protease inhibitor and transthyretin-like protein 5). Four proteins were down-regulated in the in vitro moulting-inhibited O. dentatum L3s in comparison to their controls and also over-expressed in L3s during exsheathment, and nine protein homologues could be linked to dauer formation in the free-living nematode Caenorhabditis elegans, indicating that these molecules are likely to act on all four moults in O. dentatum and might be part of a conserved pathway or mechanism of moulting in related nematode species. This first proteomic analysis of the moulting process of O. dentatum improves the understanding of the molecular and biochemical mechanisms and regulating pathways underlying this fundamental developmental process. This study might have implications for other nematodes and provides a foundation for tackling a range of basic and applied aspects of developmental parasitology and exploring new intervention targets.


Publication(s) resulting from University thesis:

Ondrovics, M; Silbermayr, K; Mitreva, M; Young, ND; Gasser, RB; Joachim, A (2014): Proteomics elucidates key molecules involved in exsheathment in vitro in Oesophagostomum dentatum. Int J Parasitol. 2014; 44(11):759-764
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Ondrovics, M; Silbermayr, K; Mitreva, M; Young, ND; Razzazi-Fazeli, E; Gasser, RB; Joachim, A (2013): Proteomic analysis of Oesophagostomum dentatum (Nematoda) during larval transition, and the effects of hydrolase inhibitors on development. PLoS One. 2013; 8(5):e63955
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