Project description:This study investigates sex-biased gene expression between populations of Atlantic and Pacific salmon lice, Lepeophtheirus salmonis. Two Atlantic L. salmonis populations were previously used for an array study (GSE56024) while a third dataset using Pacific L. salmonis was novel. Using all three populations, a consensus-based, meta-analysis approach was used to identify sex-biased and sex-specific genes.
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:This study investigates transcriptomic responses of Atlantic salmon lice, Lepeophtheirus salmonis exposed to cypermethrin, a commonly used antiparasitic agent used in aquaculture. Copepodid L. salmonis were exposed to cypermethrin (Betamax®) at a concentration of 1.0ppb
Project description:The transcriptional profile of intracellular P. salmonis was determined using a whole-genome microarray. Our microarray contained 5,309 different probes targeting 2,850. In our experimental design, the gene expression profile obtained from intracellular P. salmonis was compared with the transcriptome of control bacteria grown in culture medium. RNA from P. salmonis and SHK-1 cells were extracted simultaneously to avoid changes in transcriptomic profile after the bacterial purification process and eukaryotic RNA was depleted using the MicrobEnrich Kit.
Project description:Flagella-driven motility of Salmonella enterica serovar Typhimurium facilitates host colonization. However, the large extracellular flagellum is also a prime target for the immune system. As consequence, expression of flagella is bistable within a population of Salmonella, resulting in flagellated and non-flagellated subpopulations. This allows the bacteria to maximize fitness in hostile environments. The degenerate EAL-domain protein RflP (formerly YdiV) is responsible for the bistable expression of flagella by directing the flagellar master regulatory complex FlhD4C2 to proteolytic degradation. The environmental cues controlling expression of rflP and thus the bistable flagellar biosynthesis remain ambiguous. Here, we demonstrate that RflP responds to cell envelope stress and alterations of outer membrane integrity. Lipopolysaccharide (LPS) truncation mutants of Salmonella Typhimurium exhibited increasing motility defects due to downregulation of flagellar gene expression. Transposon mutagenesis and genetic profiling revealed that σ24 (RpoE) and Rcs phosphorelay-dependent cell envelope stress response systems sense modifications of lipopolysaccharide, low pH activity of the complement system. This subsequently results in activation of RflP expression and degradation of FlhD4C2 via ClpXP. We speculate that diverse hostile environments inside the host might result in cell envelope damage and would thus trigger the repression of resource-costly and immunogenic flagella biosynthesis via activation of the cell envelope stress response.
Project description:Genetic variations in drug metabolising enzymes play a role in how individuals respond to drugs. Pharmacogene variation data in the Ghanaian population is limited and this study looks at exploring common variations that exist in our population for commonly used drugs. Samples were validated with PCR-RFLP for accuracy
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:This SuperSeries is composed of the following subset Series: GSE26981: Responses to ectoparasite salmon louse (Lepeophtheirus salmonis) in skin of Atlantic salmon GSE26984: Responses to ectoparasite salmon louse (Lepeophtheirus salmonis) in spleen of Atlantic salmon Refer to individual Series
Project description:Salmon infected with an ectoparasitic marine copepod, the salmon louse Lepeophtheirus salmonis, incur a wide variety of consequences depending upon host sensitivity. Juvenile pink salmon (Oncorhynchus gorbuscha) migrate from natal freshwater systems to the ocean at a young age relative to other Pacific salmon, and require rapid development of appropriate defences against marine pathogens. We analyzed the early transcriptomic responses of naïve juvenile pink salmon of sizes 0.3g (no scales), 0.7g (mid-scale development) and 2.4g (scales fully developed) to a low-level laboratory exposure with early moult stage L. salmonis. All infected size groups exhibited unique transcriptional profiles. Inflammation and inhibition of cell proliferation was identified in the smallest size class (0.3g), while increased glucose absorption and retention was identified in the middle size class (0.7g). Tissue-remodelling genes were also up-regulated in both the 0.3g and 0.7g size groups. Profiles of the 2.4g size class indicated cell-mediated immunity and possibly parasite-induced growth augmentation. Understanding a size-based threshold of resistance to L. salmonis is important for fisheries management. This work characterizes molecular responses reflecting the gradual development of innate immunity to L. salmonis between the susceptible (0.3g) and refractory (2.4g) pink salmon size classes.