Evidence of the Presence of a Functional Dot/Icm Type IV-B Secretion System in the Fish Bacterial Pathogen Piscirickettsia salmonis
Open Access
- 28 January 2013
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 8 (1), e54934
- https://doi.org/10.1371/journal.pone.0054934
Abstract
Piscirickettsia salmonis is a fish bacterial pathogen that has severely challenged the sustainability of the Chilean salmon industry since its appearance in 1989. As this Gram-negative bacterium has been poorly characterized, relevant aspects of its life cycle, virulence and pathogenesis must be identified in order to properly design prophylactic procedures. This report provides evidence of the functional presence in P. salmonis of four genes homologous to those described for Dot/Icm Type IV Secretion Systems. The Dot/Icm System, the major virulence mechanism of phylogenetically related pathogens Legionella pneumophila and Coxiella burnetii, is responsible for their intracellular survival and multiplication, conditions that may also apply to P. salmonis. Our results demonstrate that the four P. salmonis dot/icm homologues (dotB, dotA, icmK and icmE) are expressed both during in vitro tissue culture cells infection and growing in cell-free media, suggestive of their putative constitutive expression. Additionally, as it happens in other referential bacterial systems, temporal acidification of cell-free media results in over expression of all four P. salmonis genes, a well-known strategy by which SSTIV-containing bacteria inhibit phagosome-lysosome fusion to survive. These findings are very important to understand the virulence mechanisms of P. salmonis in order to design new prophylactic alternatives to control the disease.This publication has 65 references indexed in Scilit:
- Dot/Icm Type IVB Secretion System Requirements for Coxiella burnetii Growth in Human MacrophagesmBio, 2011
- Microreview: Type IV secretion in the obligatory intracellular bacterium Anaplasma phagocytophilumCellular Microbiology, 2010
- An evaluation of potential reference genes for stability of expression in two salmonid cell lines after infection with either Piscirickettsia salmonis or IPNVBMC Research Notes, 2010
- Piscirickettsia salmonis induces apoptosis in macrophages and monocyte‐like cells from rainbow troutJournal of Cellular Biochemistry, 2010
- A systematic classification of Plasmodium falciparum P-loop NTPases: structural and functional correlationMalaria Journal, 2009
- Protein secretion systems in bacterial-host associations, and their description in the Gene OntologyBMC Microbiology, 2009
- Clustal W and Clustal X version 2.0Bioinformatics, 2007
- The Type IV Secretion System ofSinorhizobium melilotiStrain 1021 Is Required for Conjugation but Not for Intracellular SymbiosisJournal of Bacteriology, 2007
- Identification of Non-dot/icmSuppressors of theLegionella pneumophilaΔdotLLethality PhenotypeJournal of Bacteriology, 2006
- Analysis of Relative Gene Expression Data Using Real-Time Quantitative PCR and the 2−ΔΔCT MethodMethods, 2001