Project description:Silver exposure is toxic to fish due to disturbances of normal gill function. A proposed toxicity mechanism of silver nanoparticles (AgNP) is derived from the release of silver ions, similar to silver nitrate (AgNO3). However, some datasets support the fact that AgNP can have unique toxic effects that are mediated at the gill. To determine if differences between AgNO3 and AgNP toxicities exist, fathead minnows were exposed to 20 nm PVP- or citrate-coated silver nanoparticles (PVP-AgNP; citrate-AgNP) at the nominal concentration of 200 μg/L or AgNO3 at nominal 6 μg/L for 96 hr. This nominal concentration was applied to approximate the dissolved fraction of Ag in the AgNP suspensions. Mucus production in the water was measured. While mucus production was initially significantly increased in the first 4 h of exposure in all silver treatments compared to control, a decrease in mucus production was observed following 24-96 h of exposure. To determine which genes/pathways are driving this shift in mucus production, gills were dissected and microarray analysis was performed. Hierarchal clustering of differentially expressed genes revealed that all samples distinctly clustered by treatment. There were 109 differentially expressed genes shared among all Ag treatments compared to controls. However, there were 185, 423, and 615 differentially expressed genes unique to AgNO3, PVP-AgNP, and citrate-AgNP, relative to control. While functional analysis indicated several common enriched pathways, such as aryl hydrocarbon receptor signaling, this analysis also indicated some unique pathways between nanosilver and AgNO3. Our results show that AgNO3, PVP-AgNP, and citrate-AgNP exposure affected mucus production in fish gills and also lead to common and unique transcriptional changes.
Project description:Gills of teleost fish represent a vital multifunctional organ; however, they are subjected to environmental stressors, causing gill damage. Gill damage is associated with significant losses in the Atlantic salmon aquaculture industry. Gill disorders due to environmental stressors are exacerbated by global environmental changes, especially with open-net pen aquaculture (as farmed fish lack the ability to escape those events). The local and systemic response to gill damage, concurrent with several environmental insults, are not well investigated. We performed field sampling to collect gill and liver tissue after several environmental insults. Using a 44K salmonid microarray platform, we aimed to compare the transcriptomes of pristine and moderately damaged gill tissue. The gill damage-associated biomarker genes and associated qPCR assays arising from this study will be valuable in future research aimed at developing therapeutic diets to improve farmed salmon gill health.
Project description:The salmon gill poxvirus (SGPV) is a large DNA virus that infects gill epithelial cells in Atlantic salmon and is associated with acute high mortality disease outbreaks in aquaculture. The pathological effects of SGPV infection include gill epithelial apoptosis in the acute phase of the disease and hyperplasia of gill epithelial cells in surviving fish, causing damage to the gill respiratory surface. Transcriptome responses to virus were assessed in gills at different stages of disease
Project description:Understanding natural defence mechanisms against parasites can be a valuable tool for the development of innovative therapies. In this study, we investigated the interplay between the gill mucus metabolome and microbiome of Chaetodon lunulatus, a butterflyfish known to avoid gill monogeneans whilst living amongst closely related parasitized species. In an attempt to identify metabolites and OTUs potentially involved in parasite defence mechanisms, we studied the metabolome (LC-MS/MS) and microbiome of several sympatric butterflyfish species, including the only non-parasitized species C. lunulatus. After observing significant differences between the metabolome and microbiome of parasitized versus non-parasitized fish (PCoA, ANOSIM), we obtained the discriminant metabolites and OTUs using a supervised analysis. Some of the most important discriminant metabolites were identified as peptides, and three new β-subunit haemoblogin-derived peptides from C. lunulatus (CLHbβ-1, CLHbβ-2 and CLHbβ-3) were purified, characterised and synthesised. We also identified specific bacterial families and OTUs typical from low-oxygen habitats in C. lunulatus gill mucus. By using a correlation network between the two datasets, we found a Fusobacteriaceae strain exclusively present in C. lunulatus highly correlated to the peptides. Finally, we discuss the possible involvement of these peptides and Fusobacteriaceae in monogenean avoidance by this fish species.
Project description:Animal mucosal barriers constantly interact with the external environment and this interaction is markedly different in aquatic and terrestrial environments. Transitioning from water to land was a critical step in vertebrate evolution but the immune adaptations that mucosal barriers such as the skin underwent during that process are essentially unknown. Vertebrate animals such as the African lungfish have a bimodal life, switching from freshwater to terrestrial habitats when environmental conditions are not favorable. African lungfish skin mucus secretions contribute to the terrestrialization process by forming a cocoon that surrounds and protect the lungfish body. The goal of this study is to characterize the skin mucus immunoproteome of African lungfish, Protopterus dolloi, before and during the induction phase of terrestrialization as well as the immunoproteome of the gill mucus during the terrestrialization induction phase. Using LC-MS/MS, we identified a total of a total of 974 proteins using a lungfish Illumina RNA-seq database and 880 proteins using a lungfish 454 RNA-seq database for annotation in the three samples analyzed (control skin mucus, terrestrialized skin mucus and terrestrialized gill mucus). The terrestrialized skin mucus proteome was enriched in proteins with known antimicrobial functions such as histones and S100 proteins. In support, gene ontology analyses showed that the terrestrialized skin mucus proteome has predicted functions in processes such as viral process, defense response to Gram negative bacterium and tumor necrosis factor mediated signaling. Importantly, we observed a switch in immunoglobulin heavy chain secretion upon terrestrialization, with IgW1L and IgM1 present in control skin mucus and IgW1L, IgM1 and IgM2 in terrestrialized skin mucus. Combined, these results indicate an increase investment in the production of unique immune molecules in P. dolloi skin mucus in response to terrestrialization that likely better protect lungfish against external aggressors found in land.
Project description:Animal mucosal barriers constantly interact with the external environment and this interaction is markedly different in aquatic and terrestrial environments. Transitioning from water to land was a critical step in vertebrate evolution but the immune adaptations that mucosal barriers such as the skin underwent during that process are essentially unknown. Vertebrate animals such as the African lungfish have a bimodal life, switching from freshwater to terrestrial habitats when environmental conditions are not favorable. African lungfish skin mucus secretions contribute to the terrestrialization process by forming a cocoon that surrounds and protect the lungfish body. The goal of this study is to characterize the skin mucus immunoproteome of African lungfish, Protopterus dolloi, before and during the induction phase of terrestrialization as well as the immunoproteome of the gill mucus during the terrestrialization induction phase. Using LC-MS/MS, we identified a total of a total of 974 proteins using a lungfish Illumina RNA-seq database and 880 proteins using a lungfish 454 RNA-seq database for annotation in the three samples analyzed (control skin mucus, terrestrialized skin mucus and terrestrialized gill mucus). The terrestrialized skin mucus proteome was enriched in proteins with known antimicrobial functions such as histones and S100 proteins. In support, gene ontology analyses showed that the terrestrialized skin mucus proteome has predicted functions in processes such as viral process, defense response to Gram negative bacterium and tumor necrosis factor mediated signaling. Importantly, we observed a switch in immunoglobulin heavy chain secretion upon terrestrialization, with IgW1L and IgM1 present in control skin mucus and IgW1L, IgM1 and IgM2 in terrestrialized skin mucus. Combined, these results indicate an increase investment in the production of unique immune molecules in P. dolloi skin mucus in response to terrestrialization that likely better protect lungfish against external aggressors found in land.