O. Parisi | University of Liege (original) (raw)

Papers by O. Parisi

European Journal of Plant Pathology, 2011

... Version imprimable. Sabrina Vandeplas, Christopher Marcq, Robin Dubois Dauphin, Yves Beckers,... more ... Version imprimable. Sabrina Vandeplas, Christopher Marcq, Robin Dubois Dauphin, Yves Beckers, Philippe Thonart et André Théwis. Contamination of poultry flocks by the human pathogen Campylobacter spp. and strategies to reduce its prevalence at the farm level. ...

New Disease Reports, 2014

Enzyme research, 2014

Lactoperoxidase is a member of the family of the mammalian heme peroxidases which have a broad sp... more Lactoperoxidase is a member of the family of the mammalian heme peroxidases which have a broad spectrum of activity. Their best known effect is their antimicrobial activity that arouses much interest in in vivo and in vitro applications. In this context, the proper use of lactoperoxidase needs a good understanding of its mode of action, of the factors that favor or limit its activity, and of the features and properties of the active molecules. The first part of this review describes briefly the classification of mammalian peroxidases and their role in the human immune system and in host cell damage. The second part summarizes present knowledge on the mode of action of lactoperoxidase, with special focus on the characteristics to be taken into account for in vitro or in vivo antimicrobial use. The last part looks upon the characteristics of the active molecule produced by lactoperoxidase in the presence of thiocyanate and/or iodide with implication(s) on its antimicrobial activity.

BMC Genomics, 2014

Background: Scab, caused by the fungus Venturia inaequalis, is one of the most important diseases... more Background: Scab, caused by the fungus Venturia inaequalis, is one of the most important diseases of cultivated apple. While a few scab resistance genes (R genes) governing qualitative resistance have been isolated and characterized, the biological roles of genes governing quantitative resistance, supposed to be more durable, are still unknown. This study aims to investigate the molecular mechanisms involved in the partial resistance of the old Belgian apple cultivar 'Président Roulin' against V. inaequalis. Results: A global gene expression analysis was conducted in 'Président Roulin' (partially resistant) and in 'Gala' (susceptible) challenged by V. inaequalis by using the cDNA-AFLP method (cDNA-Amplified Fragment Length Polymorphism). Transcriptome analysis revealed significant modulation (up-or down-regulation) of 281 out of approximately 20,500 transcript derived fragments (TDFs) in 'Président Roulin' 48 hours after inoculation. Sequence annotation revealed similarities to several genes encoding for proteins belonging to the NBS-LRR and LRR-RLK classes of plant R genes and to other defense-related proteins. Differentially expressed genes were sorted into functional categories according to their gene ontology annotation and this expression signature was compared to published apple cDNA libraries by Gene Enrichment Analysis. The first comparison was made with two cDNA libraries from Malus x domestica uninfected leaves, and revealed in both libraries a signature of enhanced expression in 'Président Roulin' of genes involved in response to stress and photosynthesis. In the second comparison, the pathogen-responsive TDFs from the partially resistant cultivar were compared to the cDNA library from inoculated leaves of Rvi6 (HcrVf2)-transformed 'Gala' lines (complete disease resistance) and revealed both common physiological events, and notably differences in the regulation of defense response, the regulation of hydrolase activity, and response to DNA damage. TDFs were in silico mapped on the 'Golden Delicious' apple reference genome and significant co-localizations with major scab R genes, but not with quantitative trait loci (QTLs) for scab resistance nor resistance gene analogues (RGAs) were found.

Viroids are non encapsidated small RNA plant pathogens unable to produce any protein. They are ab... more Viroids are non encapsidated small RNA plant pathogens unable to produce any protein. They are able to infect dramatically a broad range of plants including herbaceous and tree crops. The ways by which viroids are able to induce diseases are actually unknown. However, recent studies have shown that viroids are able to regulate the gene expression of their hosts, they can modify the host-protein phosphorylation sensibility and they interact with host-protein implicated RNA trafficking and protein phosphorylation. Moreover during their evolution plants have developed a mechanism able to regulate their gene expression and to degrade exogenous RNAs like viroids: the gene silencing. Unfortunately, this pathway seems, now, also highly implicated in the symptoms development. This review describes studies that are realized since a few years to increase the knowledge about the plant-viroid relationship.

Virology, 2007

Nucleotide sequences of a broad range of Peach Latent Mosaic Viroid (PLMVd) variants were determi... more Nucleotide sequences of a broad range of Peach Latent Mosaic Viroid (PLMVd) variants were determined. The variants were isolated from peach, pear, and almond tree samples collected in Tunisia. Sequence analysis confirmed the high variability of PLMVd, as no less than 119 new variants were identified. Variations included new polymorphic positions, insertions of 11 to 14 nucleotides, and new mutations within the hammerhead self-cleavage motifs. We provide the first covariation-based evidence for certain stems within the proposed secondary structure. Our covariation analysis also strengthens the view that a pseudoknot closes the replication domain. On the basis of phylogenetic tree studies and informative positions, PLMVd variants are proposed to cluster into groups and subgroups likely to have resulted from recombination events. PLMVd thus emerges as a suitable viroid for retracing the evolution of an RNA genome.