Project description:The aquaculture industry has confronted severe economic losses due to infectious diseases in the last years. Piscirickettsiosis or Salmonid Rickettsial Septicaemia (SRS) is the bacterial disease caused by Piscirickettsia salmonis. This Gram-negative, non-motile, cellular pathogen has the ability to infect, survive, replicate, and propagate in salmonid monocytes/macrophages generating a systemic infection characterized by the colonization of several organs including kidney, liver, spleen, intestine, brain, ovary and gills. In this study, we attempted to determine whether global gene expression differences can be detected in different genetic groups of Atlantic salmon as a result of Piscirickettsia salmonis infection. Moreover, we sought to characterize the fish transcriptional response in order to reveal the mechanisms that might confer resistance in Atlantic salmon to an infection with Piscirickettsia salmonis. In doing so, after challenging with Piscirickettsia salmonis, we selected the families with the highest (HS) and the lowest (LS) recorded susceptibility for gene expression analysis using 32K cGRASP microarrays. Our results revealed in LS families expression changes are linked to iron depletion, as well as, low contents of iron in kidney cells and low bacterial load, indicated that the iron-withholding strategy of innate immunity is part of the mechanism of resistance against Piscirickettsia salmonis. This information contributes to elucidate the underlying mechanisms of resistance to Piscirickettsia salmonis infection in Atlantic salmon and to identify new candidate genes for selective breeding programmes.
Project description:The aquaculture industry has confronted severe economic losses due to infectious diseases in the last years. Piscirickettsiosis or Salmonid Rickettsial Septicaemia (SRS) is the bacterial disease caused by Piscirickettsia salmonis. This Gram-negative, non-motile, cellular pathogen has the ability to infect, survive, replicate, and propagate in salmonid monocytes/macrophages generating a systemic infection characterized by the colonization of several organs including kidney, liver, spleen, intestine, brain, ovary and gills. In this study, we attempted to determine whether global gene expression differences can be detected in different genetic groups of Atlantic salmon as a result of Piscirickettsia salmonis infection. Moreover, we sought to characterize the fish transcriptional response in order to reveal the mechanisms that might confer resistance in Atlantic salmon to an infection with Piscirickettsia salmonis. In doing so, after challenging with Piscirickettsia salmonis, we selected the families with the highest (HS) and the lowest (LS) recorded susceptibility for gene expression analysis using 32K cGRASP microarrays. Our results revealed in LS families expression changes are linked to iron depletion, as well as, low contents of iron in kidney cells and low bacterial load, indicated that the iron-withholding strategy of innate immunity is part of the mechanism of resistance against Piscirickettsia salmonis. This information contributes to elucidate the underlying mechanisms of resistance to Piscirickettsia salmonis infection in Atlantic salmon and to identify new candidate genes for selective breeding programmes. Forty full-sibling families of Atlantic salmon (Salmo salar) were infected by intraperitoneal injection with 0.2 mL Piscirickettsia salmonis (PS889, isolated from Oncorhynchus kisutch, 1M-CM-^W104 PFU/mL). After forty days, the fishes were harvested and the cumulative mortality (dead fish / total fish) for each family was calculated. For the second challenge, the six families with the highest cumulative mortality levels were considered of relatively high susceptibility (HS) and the six families with the lowest cumulative mortality levels were considered of relatively low susceptibility (LS) to the infection. Five control and five infected fish from three HS and three LS families were analyzed. For each HS and LS family, pools of RNA from control and infected fish were prepared separately and were reverse transcribed. Four slides were for each used family hybridized including two dye-swaped slides. Labeled samples were hybridized on a 32K cDNA microarray, developed at the Consortium for Genomics Research on All Salmonids Project (cGRASP), GEO accession number: GPL8904.
Project description:An effective and economical vaccine against the Piscirickettsia salmonis pathogen is needed for sustainable salmon farming and to reduce disease-related economic losses. Consequently, the aquaculture industry urgently needs to investigate efficient prophylactic measures. Three protein-based vaccine prototypes against Piscirickettsia salmonis were prepared from a highly pathogenic Chilean isolate. Only one vaccine effectively protected Atlantic salmon (Salmo salar), in correlation with the induction of Piscirickettsia-specific IgM antibodies and a high induction of transcripts encoding pro-inflammatory cytokines (i.e. Il-1β and TNF-α). In addition, we studied the proteome fraction protein of P. salmonis strain Austral-005 using multidimensional protein identification technology. The analyzes identified 87 proteins of different subcellular origins, such as the cytoplasmic and membrane compartment, where many of them have virulence functions. The other two prototypes activated only the innate immune responses, but did not protect Salmo salar against Piscirickettsia salmonis. These results suggest that the knowledge of the formulation of vaccines based on P. salmonis proteins is useful as an effective therapy, this demonstrates the importance of the different research tools to improve the study of the different immune responses, resistance to diseases in the Atlantic salmon. We suggest that this vaccine can help prevent widespread infection by P. salmonis, in addition to being able to be used as a booster after a primary vaccine to maintain high levels of circulating protective antibodies, greatly helping to reduce the economic losses caused by the pathogen.
Project description:Fuentealb2016 - Genome-scale metabolic
reconstruction (iPF215) of Piscirickettsia salmonis LF-89
This model is described in the article:
Genome-scale metabolic
reconstruction for the insidious bacterium in aquaculture
Piscirickettsia salmonis.
Fuentealba P, Aros C, Latorre Y,
Martínez I, Marshall S, Ferrer P, Albiol J, Altamirano
C.
Bioresour. Technol. 2017 Jan; 223:
105-114
Abstract:
Piscirickettsia salmonis is a fish bacterium that causes the
disease piscirickettsiosis in salmonids. This pathology is
partially controlled by vaccines. The lack of knowledge has
hindered its culture on laboratory and industrial scale. The
study describes the metabolic phenotype of P. salmonis in
culture. This study presents the first genome-scale model
(iPF215) of the LF-89 strain of P. salmonis, describing the
central metabolic pathway, biosynthesis and molecule
degradation and transport mechanisms. The model was adjusted
with experiment data, allowing the identification of the
capacities that were not predicted by the automatic annotation
of the genome sequences. The iPF215 model is comprised of 417
metabolites, 445 reactions and 215 genes, was used to reproduce
the growth of P. salmonis (?max 0.052±0.005h(-1)). The
metabolic reconstruction of the P. salmonis LF-89 strain
obtained in this research provides a baseline that describes
the metabolic capacities of the bacterium and is the basis for
developing improvements to its cultivation for vaccine
formulation.
This model is hosted on
BioModels Database
and identified by:
MODEL1610250000.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.