RÉSUMÉ
Activin signaling is essential for proper embryonic, skeletal muscle, and reproductive development. Duplication of the pathway in teleost fish has enabled diversification of gene function across the pathway but how gene duplication influences the function of activin signaling in non-mammalian species is poorly understood. Full characterization of activin receptor signaling pathway expression was performed across embryonic development and during early skeletal muscle growth in rainbow trout (RBT, Oncorhynchus mykiss). Rainbow trout are a model salmonid species that have undergone two additional rounds of whole genome duplication. A small number of genes were expressed early in development and most genes increased expression throughout development. There was limited expression of activin Ab in RBT embryos despite these genes exhibiting significantly elevated expression in post-hatch skeletal muscle. CRISPR editing of the activin Aa1 ohnolog and subsequent production of meiotic gynogenetic offspring revealed that biallelic disruption of activin Aa1 did not result in developmental defects, as occurs with knockout of activin A in mammals. The majority of gynogenetic offspring exhibited homozygous activin Aa1 genotypes (wild type, in-frame, or frameshift) derived from the mosaic founder female. The research identifies mechanisms of specialization among the duplicated activin ohnologs across embryonic development and during periods of high muscle growth in larval and juvenile fish. The knowledge gained provides insights into potential viable gene-targeting approaches for engineering the activin receptor signaling pathway and establishes the feasibility of employing meiotic gynogenesis as a tool for producing homozygous F1 genome-edited fish for species with long-generation times, such as salmonids.
Sujet(s)
Muscles squelettiques , Oncorhynchus mykiss , Transduction du signal , Animaux , Oncorhynchus mykiss/génétique , Oncorhynchus mykiss/croissance et développement , Oncorhynchus mykiss/métabolisme , Oncorhynchus mykiss/embryologie , Muscles squelettiques/métabolisme , Muscles squelettiques/croissance et développement , Femelle , Régulation de l'expression des gènes au cours du développement , Activines/métabolisme , Activines/génétique , Développement embryonnaire/génétique , Développement musculaire/génétique , Édition de gène , Embryon non mammalien/métabolisme , Systèmes CRISPR-Cas , Récepteur activine/métabolisme , Récepteur activine/génétique , Protéines de poisson/génétique , Protéines de poisson/métabolismeRÉSUMÉ
The production and release of cortisol during stress responses are key regulators of growth in teleosts. Understanding the molecular responses to cortisol is crucial for the sustainable farming of rainbow trout (Oncorhynchus mykiss) and other salmonid species. While several studies have explored the genomic and non-genomic impacts of cortisol on fish growth and skeletal muscle development, the long-term effects driven by epigenetic mechanisms, such as cortisol-induced DNA methylation, remain unexplored. In this study, we analyzed the transcriptome and genome-wide DNA methylation in the skeletal muscle of rainbow trout seven days after cortisol administration. We identified 550 differentially expressed genes (DEGs) by RNA-seq and 9059 differentially methylated genes (DMGs) via whole-genome bisulfite sequencing (WGBS) analysis. KEGG enrichment analysis showed that cortisol modulates the differential expression of genes associated with nucleotide metabolism, ECM-receptor interaction, and the regulation of actin cytoskeleton pathways. Similarly, cortisol induced the differential methylation of genes associated with focal adhesion, adrenergic signaling in cardiomyocytes, and Wnt signaling. Through integrative analyses, we determined that 126 genes showed a negative correlation between up-regulated expression and down-regulated methylation. KEGG enrichment analysis of these genes indicated participation in ECM-receptor interaction, regulation of actin cytoskeleton, and focal adhesion. Using RT-qPCR, we confirmed the differential expression of lamb3, itga6, limk2, itgb4, capn2, and thbs1. This study revealed for the first time the molecular responses of skeletal muscle to cortisol at the transcriptomic and whole-genome DNA methylation levels in rainbow trout.
Sujet(s)
Méthylation de l'ADN , Hydrocortisone , Muscles squelettiques , Oncorhynchus mykiss , Stress physiologique , Transcriptome , Animaux , Oncorhynchus mykiss/génétique , Oncorhynchus mykiss/métabolisme , Hydrocortisone/métabolisme , Hydrocortisone/pharmacologie , Muscles squelettiques/métabolisme , Muscles squelettiques/effets des médicaments et des substances chimiques , Stress physiologique/génétique , Épigenèse génétique , Épigénomique/méthodes , Analyse de profil d'expression de gènes , Protéines de poisson/génétique , Protéines de poisson/métabolismeRÉSUMÉ
Antimicrobial peptides (AMPs) are an alternative to antibiotics for treatment and prevention of infections with a lower risk of bacterial resistance. Pituitary adenylate cyclase activating polypeptide (PACAP) is an outstanding AMP with versatile effects including antimicrobial activity and modulation of immune responses. The objective of this research was to study PACAP immunomodulatory effect on rainbow trout cell lines infected with Aeromonas salmonicida. PACAP from Clarias gariepinus (PACAP1) and a modified PACAP (PACAP5) were tested. RT-qPCR results showed that il1b and il8 expression in RTgutGC was significantly downregulated while tgfb expression was upregulated after PACAP treatment. Importantly, the concentration of IL-1ß and IFN-γ increased in the conditioned media of RTS11 cells incubated with PACAP1 and exposed to A. salmonicida. There was a poor correlation between gene expression and protein concentration, suggesting a stimulation of the translation of IL-1ß protein from previously accumulated transcripts or the cleavage of accumulated IL-1ß precursor. In-silico studies of PACAP-receptor interactions showed a turn of the peptide characteristic of PACAP-PAC1 interaction, correlated with the higher number of interactions observed with this specific receptor, which is also in agreement with the higher PACAP specificity described for PAC1 compared to VPAC1 and VPACA2. Finally, the in silico analysis revealed nine amino acids related to the PACAP receptor-associated functionality.
Sujet(s)
Aeromonas salmonicida , Cytokines , Protéines de poisson , Oncorhynchus mykiss , Polypeptide activateur de l'adénylcyclase hypophysaire , Animaux , Polypeptide activateur de l'adénylcyclase hypophysaire/génétique , Protéines de poisson/génétique , Protéines de poisson/immunologie , Aeromonas salmonicida/physiologie , Oncorhynchus mykiss/immunologie , Oncorhynchus mykiss/génétique , Cytokines/génétique , Cytokines/métabolisme , Lignée cellulaire , Maladies des poissons/immunologie , Régulation de l'expression des gènes/immunologie , Régulation de l'expression des gènes/effets des médicaments et des substances chimiques , Poissons-chats/immunologie , Poissons-chats/génétique , Infections bactériennes à Gram négatif/immunologie , Infections bactériennes à Gram négatif/médecine vétérinaire , Immunité innée/génétique , Récepteurs au polypeptide activateur de l'adénylcyclase hypophysaire/génétiqueRÉSUMÉ
The development of green aquaculture practices has led to the supplementation of fish diets with natural immunostimulants such as organic acids. This study aimed to assess the dietary effects of verjuice (VJ; unfermented unripe grapes; Vitis vinifera) on hematological parameters, skin mucosal immunity, transcriptional immune responses, and antibacterial serum activity against Aeromonas hydrophila in rainbow trout. The fish (51.0 ± 2.4 g) were randomly distributed into 15 tanks and fed ad-libitum thrice daily with diets containing different levels of VJ including 0 (control; VJ-0), 3 (VJ-3), 6 (VJ-6), 9 (VJ-9), and 12 (VJ-12) mL/kg VJ for 56 d. Results showed that immuno-hematological parameters (total white blood cells, neutrophils, and monocytes) were improved in VJ-added groups (P < 0.05). In addition, dietary VJ (9 mL/kg) modulated serum immunological parameters. Skin mucus immunology exhibited a notable increase in alkaline phosphatase, lysozyme activity, alkaline protease, total protein, total immunoglobulin, and esterase levels in VJ-9 group compared with those in the control group (P < 0.05). The mRNA expression of interleukin-1ß, interleukin-6, interleukin-8, and immunoglobulin M were significantly higher in VJ-9 group than in the control (P < 0.05). Furthermore, the results of the antibacterial evaluation showed that A. hydrophila growth was significantly inhibited in the serum samples from VJ-3 to VJ-9 groups after the 56th day and in all VJ-treated groups after the 70th (P < 0.05). In conclusion, dietary VJ is a novel immunostimulant and the optimal dietary supplementation level of 6.65-7.46 mL/kg can effectively improve immune responses in rainbow trout.
Sujet(s)
Aeromonas hydrophila , Aliment pour animaux , Régime alimentaire , Compléments alimentaires , Maladies des poissons , Immunité innée , Oncorhynchus mykiss , Vitis , Animaux , Oncorhynchus mykiss/immunologie , Oncorhynchus mykiss/génétique , Aliment pour animaux/analyse , Régime alimentaire/médecine vétérinaire , Compléments alimentaires/analyse , Aeromonas hydrophila/physiologie , Vitis/composition chimique , Maladies des poissons/immunologie , Immunité innée/effets des médicaments et des substances chimiques , Répartition aléatoire , Infections bactériennes à Gram négatif/médecine vétérinaire , Infections bactériennes à Gram négatif/immunologie , Adjuvants immunologiques/pharmacologie , Adjuvants immunologiques/administration et posologie , Immunité muqueuse/effets des médicaments et des substances chimiques , Relation dose-effet des médicamentsRÉSUMÉ
Multiple studies in a range of taxa have found links between structural variants and the development of ecologically important traits. Such variants are becoming easier to find due, in large part, to the increase in the amount of genome-wide sequence data in nonmodel organisms. The salmonids (salmon, trout, and charr) are a taxonomic group with abundant genome-wide datasets due to their importance in aquaculture, fisheries, and variation in multiple ecologically important life-history traits. Previous research on rainbow trout (Oncorhynchus mykiss) has documented a large pericentric (â¼55â Mb) chromosomal inversion (CI) on chromosome 5 (Omy05) and a second smaller (â¼14â Mb) chromosome inversion on Omy20. While the Omy05 inversion appears to be associated with multiple adaptive traits, the inversion on Omy20 has received far less attention. In this study, we re-analyze RAD-seq and amplicon data from several populations of rainbow trout (O. mykiss) to better document the structure and geographic distribution of variation in the Omy20 CI. Moreover, we utilize phylogenomic techniques to characterize both the age- and the protein-coding gene content of the Omy20 CI. We find that the age of the Omy20 inversion dates to the early stages of O. mykiss speciation and predates the Omy05 inversion by â¼450,000 years. The 2 CIs differ further in terms of the frequency of the homokaryotypes. While both forms of the Omy05 CI are found across the eastern Pacific, the ancestral version of the Omy20 CI is restricted to the southern portion of the species range in California. Furthermore, the Omy20 inverted haplotype is comparable in genetic diversity to the ancestral form, whereas derived CIs typically show substantially reduced genetic diversity. These data contribute to our understanding of the age and distribution of a large CI in rainbow trout and provide a framework for researchers looking to document CIs in other nonmodel species.
Sujet(s)
Inversion chromosomique , Oncorhynchus mykiss , Animaux , Oncorhynchus mykiss/génétique , Génétique des populations , Génome , Phylogenèse , Variation génétiqueRÉSUMÉ
Long non-coding RNA (lncRNA) is a novel emerging type of competitive endogenous RNA (ceRNA) that performs key functions in multiple biological processes. However, little is known about the roles of lncRNA under hypoxia stress in fish. Here, vascular endothelial growth factor-Aa (vegfaa) was cloned in rainbow trout (Oncorhynchus mykiss), with the complete cDNA sequence of 2914â¯bp, encoding 218 amino acids. The molecular weight of the protein was approximately 25.33â¯kDa, and contained PDGF and VEGF_C domains. Time-course and spatial expression patterns revealed that LOC110520012 was a key regulator of rainbow trout in response to hypoxia stress, and LOC110520012, miR-206-y and vegfaa exhibited a ceRNA regulatory relationship in liver, gill, muscle and rainbow trout liver cells treated with acute hypoxia. Subsequently, the targeting relationship of LOC110520012 and vegfaa with miR-206-y was confirmed by dual-luciferase reporter analysis, and overexpression of LOC110520012 mediated the inhibition of miR-206-y expression in rainbow trout liver cells, while the opposite results were obtained after LOC110520012 silencing with siRNA. We also proved that vegfaa was a target of miR-206-y in vitro and in vivo, and the vegfaa expression and anti-proliferative effect on rainbow trout liver cells regulated by miR-206-y mimics could be reversed by LOC110520012. These results suggested that LOC110520012 can positively regulate vegfaa expression by sponging miR-206-y under hypoxia stress in rainbow trout, which facilitate in-depth understanding of the molecular mechanisms of fish adaptation and tolerance to hypoxia.
Sujet(s)
Prolifération cellulaire , Foie , microARN , Oncorhynchus mykiss , ARN long non codant , Facteur de croissance endothéliale vasculaire de type A , Animaux , Oncorhynchus mykiss/génétique , microARN/génétique , ARN long non codant/génétique , Facteur de croissance endothéliale vasculaire de type A/génétique , Facteur de croissance endothéliale vasculaire de type A/métabolisme , Prolifération cellulaire/effets des médicaments et des substances chimiques , Foie/effets des médicaments et des substances chimiques , Hypoxie/génétique , Néovascularisation physiologique/effets des médicaments et des substances chimiques , Néovascularisation physiologique/génétique ,RÉSUMÉ
Reducing the negative impact of environmental and stressful factors is a crucial step in achieving sustainable aquaculture. Therefore, a study was aimed at evaluating the impacts of Coenzyme Q10 (CoQ10) supplementation on growth, relative gene expression of Growth Hormone (GH) and Insulin-like growth factor-1 (IGF-1), liver and kidney histopathology against stress induced by ammonia in Rainbow trout (Oncorhynchus mykiss). The fish were given feed containing different levels of CoQ10 for 8 weeks: Control - CoQ10 0%, G1 - CoQ10 0.1%, G2 - CoQ10 0.5% and G3 - CoQ10 1%. At the end of the experiment, fish were exposed to ammonia stress concentration at 0.6mg/L for 24 h to assess liver and kidney tissue damage. Results showed that there was a significant activity increase in GH and IGF-1 genes due to supplementation with CoQ10 alone (p < 0.05). Gene expression for GH increased about two-fold whereas that for IGF-1 experienced a four-fold upregulation compared to controls (p < 0.05). CoQ10's-related antioxidant effects probably minimized liver and kidney cellular injuries, as significant decreases were observed in ammonia-induced mortality (p < 0.05). In summary, adding CoQ10 to the diet is a potential way to improve fish production through controlling the gene expression of GH and IGF-1, as well as making fish populations more resistant to possible future stress caused by ammonia in intensive or super-intensive aquaculture systems.
Sujet(s)
Ammoniac , Compléments alimentaires , Hormone de croissance , Facteur de croissance IGF-I , Rein , Foie , Oncorhynchus mykiss , Ubiquinones , Animaux , Ammoniac/toxicité , Foie/effets des médicaments et des substances chimiques , Foie/métabolisme , Facteur de croissance IGF-I/génétique , Facteur de croissance IGF-I/métabolisme , Rein/effets des médicaments et des substances chimiques , Ubiquinones/analogues et dérivés , Ubiquinones/pharmacologie , Oncorhynchus mykiss/génétique , Hormone de croissance/génétique , Aliment pour animaux/analyse , Régime alimentaire/médecine vétérinaireRÉSUMÉ
Hypoxia, largely triggered by global warming and water contamination, has become an environmental issue of great concern, posing a great threat to aquatic ecosystem. As one of the world's most economically important fish, rainbow trout (Oncorhynchus mykiss) is extremely intolerant of hypoxic environments, however, little is known about the roles of non-coding RNAs (ncRNAs) in the response of rainbow trout to hypoxia stress. Herein, effects of moderate (Tm12L) and severe hypoxia for 12â¯h (Ts12L) and 12â¯h reoxygenation on histology, biochemical parameters (antioxidant, metabolism and immunity) and transcriptome (lncRNA, miRNA and mRNA) in rainbow trout liver were investigated. We further validated the regulatory relationships between LOC110519952, novel-m0023-5p and glut1a via dualluciferase reporter, overexpression and silencing assays. Compared with Tm12L, the liver in Ts12L showed more severe oxidative damage. Anaerobic, lipid and protein metabolism was enhanced under hypoxia stress, especially in Ts12L. We also found that Tm12L could strengthen innate immune response, which was inhibited in Ts12L. Besides, several hypoxia-related genes (glut1a, vegfaa, hmox, epoa, foxo1a and igfbp1) and ceRNA networks were identified from 1824, 427 and 545 differentially expressed mRNAs, miRNAs and lncRNAs, including LOC118965299-novel-m0179-3p-epoa, LOC110519952-novel-m0023-5p-glut1a, MSTRG.7382.2-miR-184-y-hmox and LOC110520012-miR-206-y-vegfaa. Through in vitro and in vivo functional analysis, we demonstrated that glut1a is a target of novel-m0023-5p, and LOC110519952 can positively regulate glut1a by targeting novel-m0023-5p. Introduction of LOC110519952 could attenuate the promoting effects of novel-m0023-5p on rainbow trout liver cell viability and proliferation. This study highlights the differences in the regulatory mechanism of rainbow trout under different concentrations of hypoxia stress and provides valuable data for further research on the molecular mechanisms of fish adaptation to hypoxic environments.
Sujet(s)
Oncorhynchus mykiss , Transcriptome , Animaux , Oncorhynchus mykiss/génétique , microARN/génétique , Foie/métabolisme , Stress physiologique , Hypoxie , ARN long non codant/génétique , Stress oxydatif , Immunité innée/génétiqueRÉSUMÉ
Essential for muscle fiber formation and hypertrophy, muscle stem cells, also called satellite cells, reside beneath the basal lamina of the muscle fiber. Satellite cells have been commonly identified by the expression of the Paired box 7 (Pax7) due to its specificity and the availability of antibodies in tetrapods. In fish, the identification of satellite cells remains difficult due to the lack of specific antibodies in most species. Based on the development of a highly sensitive in situ hybridization (RNAScope®) for pax7, we showed that pax7+ cells were detected in the undifferentiated myogenic epithelium corresponding to the dermomyotome at day 14 post-fertilization in rainbow trout. Then, from day 24, pax7+ cells gradually migrated into the deep myotome and were localized along the muscle fibers and reach their niche in satellite position of the fibres after hatching. Our results showed that 18 days after muscle injury, a large number of pax7+ cells accumulated at the wound site compared to the uninjured area. During the in vitro differentiation of satellite cells, the percentage of pax7+ cells decreased from 44% to 18% on day 7, and some differentiated cells still expressed pax7. Taken together, these results show the dynamic expression of pax7 genes and the follow-up of these muscle stem cells during the different situations of muscle fiber formation in trout.
Sujet(s)
Oncorhynchus mykiss , Facteur de transcription PAX7 , Régénération , Cellules satellites du muscle squelettique , Animaux , Différenciation cellulaire , Régulation de l'expression des gènes au cours du développement , Développement musculaire/génétique , Oncorhynchus mykiss/métabolisme , Oncorhynchus mykiss/génétique , Facteur de transcription PAX7/métabolisme , Facteur de transcription PAX7/génétique , Régénération/génétique , Cellules satellites du muscle squelettique/métabolisme , Cellules satellites du muscle squelettique/cytologieRÉSUMÉ
The genomes of plant and animal species are influenced by ancestral whole-genome duplication (WGD) events, which have profound impacts on the regulation and function of gene networks. To gain insight into the consequences of WGD events, we characterized the sequence conservation and expression patterns of ohnologs in the highly duplicated activin receptor signaling pathway in rainbow trout (RBT). The RBT activin receptor signaling pathway is defined by tissue-specific expression of inhibitors and ligands and broad expression of receptors and Co-Smad signaling molecules. Signaling pathway ligands exhibited shared expression, while inhibitors and Smad signaling molecules primarily express a single dominant ohnolog. Our findings suggest that gene function influences ohnolog evolution following duplication of the activin signaling pathway in RBT.
Sujet(s)
Évolution moléculaire , Duplication de gène , Oncorhynchus mykiss , Transduction du signal , Animaux , Oncorhynchus mykiss/génétique , Génome , Activines/métabolisme , Activines/génétique , Récepteur activine/génétique , Récepteur activine/métabolismeRÉSUMÉ
Since the first introduction from North America more than a century ago, rainbow trout (Oncorhynchus mykiss) have rapidly established self-sustaining populations in major river basins of Patagonia. Many generations later, only the freshwater resident life history is expressed in the Chubut and Negro rivers of northern Argentinian Patagonia, whereas both the resident and anadromous life histories are found in the Santa Cruz River of southern Argentina. Despite previous studies that have tried to identify the sources of these introduced populations, uncertainty still exists. Here we combined data from many single-nucleotide polymorphisms and microsatellite loci in O. mykiss populations from Argentina and North America to evaluate putative source populations, gene flow between Argentinian river basins, and genetic diversity differences between Argentinian and North American populations. We found that populations from northern and southern Patagonia are highly differentiated and have limited gene flow between them. Phylogeographic analysis also confirmed that they have separate origins, with the northern populations most closely related to the domesticated rainbow trout strains that are raised worldwide and the Santa Cruz River populations most closely related to North American populations from California and Oregon that have an anadromous component. In addition, fish with different life histories in the Santa Cruz River were found to constitute a single interbreeding population. No evidence was found of reduced genetic variation in introduced rainbow trout, suggesting multiple contributing sources. In spite of these advances in understanding, significant questions remain regarding the origins and evolution of the introduced O. mykiss in Patagonia.
Sujet(s)
Flux des gènes , Variation génétique , Répétitions microsatellites , Oncorhynchus mykiss , Polymorphisme de nucléotide simple , Animaux , Oncorhynchus mykiss/génétique , Argentine , Rivières , Phylogéographie , Génétique des populationsRÉSUMÉ
Infectious hematopoietic necrosis (IHN), caused by IHN virus, is a highly contagious and lethal disease that seriously hampers the development of rainbow trout (Oncorhynchus mykiss) aquaculture. However, the immune response mechanism of rainbow trout underlying IHNV infection remains largely unknown. MicroRNAs act as post-transcriptional regulators of gene expression and perform a crucial role in fish immune response. Herein, the regulatory mechanism and function of miR-206 in rainbow trout resistance to IHNV were investigated by overexpression and silencing. The expression analysis showed that miR-206 and its potential target receptor-interacting serine/threonine-protein kinase 2 (RIP2) exhibited significant time-dependent changes in headkidney, spleen and rainbow trout primary liver cells infected with IHNV and their expression displayed a negative correlation. In vitro, the interaction between miR-206 and RIP2 was verified by luciferase reporter assay, and miR-206 silencing in rainbow trout primary liver cells markedly increased RIP2 and interferon (IFN) expression but significantly decreased IHNV copies, and opposite results were obtained after miR-206 overexpression or RIP2 knockdown. In vivo, overexpressed miR-206 with agomiR resulted in a decrease in the expression of RIP2 and IFN in liver, headkidney and spleen. This study revealed the key role of miR-206 in anti-IHNV, which provided potential for anti-viral drug screening in rainbow trout.
Sujet(s)
Maladies des poissons , Protéines de poisson , Virus de la nécrose hématopoïétique infectieuse , microARN , Oncorhynchus mykiss , Infections à Rhabdoviridae , Animaux , Oncorhynchus mykiss/immunologie , Oncorhynchus mykiss/génétique , Maladies des poissons/immunologie , Maladies des poissons/virologie , Virus de la nécrose hématopoïétique infectieuse/physiologie , Infections à Rhabdoviridae/médecine vétérinaire , Infections à Rhabdoviridae/immunologie , microARN/génétique , microARN/immunologie , microARN/métabolisme , Protéines de poisson/génétique , Protéines de poisson/immunologie , Immunité innée/génétiqueRÉSUMÉ
Chemokines are cytokines with chemoattractant capacities that exert their physiological functions through the binding of chemokine receptors. Thus, chemokine and receptor complexes exert important roles in regulating development and homeostasis during routine immune surveillance and inflammation. Compared to mammals, the physiology and structure of chemokine receptors in fish have not been systematically studied. Furthermore, the salmonid-specific whole genome duplication has significantly increased the number of functional paralogs of chemokine receptors. In this context, in the current study, trout exhibited 17 cxcr genes, including 12 newly identified and 5 previously identified receptors. Interestingly, gene expression of brain cxcr1 and cxcr4, kidney cxcr3 and cxcr4, and spleen cxcr3, cxcr4, and cxcr5 subtypes were altered by bacterial infection, whereas brain cxcr1, kidney cxcr1 and cxcr7, and liver cxcr2, cxcr3, and cxcr4 subtypes were changed in response to environmental changes. Based on protein structures predicted by ColabFold, the conserved amino acids in binding pockets between trout CXCR4.1 subtypes and human CXCR4 were also analyzed. Our study is valuable from a comparative point of view, providing new insights into the identification and physiology of salmonid chemokine receptors.
Sujet(s)
Oncorhynchus mykiss , Animaux , Humains , Oncorhynchus mykiss/génétique , Génome , Transduction du signal , Mammifères/génétiqueRÉSUMÉ
Triphenyl phosphate (TPhP) is an organophosphate flame retardant and plasticizer that is added to a wide variety of consumer and industrial products. It is also a ubiquitous environmental pollutant. Exposure to TPhP has been shown to alter gene expression in metabolic and estrogenic signaling pathways in in vitro and in vivo models of a variety of species, and as such, is considered to be an endocrine disrupting chemical. Exposure to endocrine disrupting chemicals is increasingly being associated with changes to the epigenome, especially during embryonic development. The aim of this study was to evaluate whether TPhP exposure in aquatic ecosystems has the ability to alter the epigenome in two immortal cell lines derived from trout (Oncorhynchus mykiss). This study assessed whether 24 h exposure to TPhP resulted in changes to histone modification and DNA methylation profiles in steelhead trout embryonic cells and rainbow trout gill epithelial cells. Results show that several epigenetic modifications on histone H3 and DNA methylation are altered in the embryonic cells following TPhP exposure, but not in the gill epithelial cells. Specifically, histone H3 acetylation, histone H3 mono-methylation and global DNA methylation were found to be reduced. The alterations of these epigenetic modification profiles in the embryonic cells suggest that exposure to TPhP during fetal development may alter gene expression in the developing embryo, likely in metabolic and estrogenic pathways. The impacts to the epigenome determined in this study may even carry multigenerational detrimental effects on human and ecosystem health, which requires further investigation.
Sujet(s)
Méthylation de l'ADN , Ignifuges , Oncorhynchus mykiss , Organophosphates , Polluants chimiques de l'eau , Animaux , Ignifuges/toxicité , Oncorhynchus mykiss/embryologie , Oncorhynchus mykiss/génétique , Méthylation de l'ADN/effets des médicaments et des substances chimiques , Organophosphates/toxicité , Polluants chimiques de l'eau/toxicité , Épigénome/effets des médicaments et des substances chimiques , Lignée cellulaire , Perturbateurs endocriniens/toxicité , Branchies/effets des médicaments et des substances chimiques , Branchies/métabolisme , Épigenèse génétique/effets des médicaments et des substances chimiques , Embryon non mammalien/effets des médicaments et des substances chimiques , Histone/métabolisme , Cellules épithéliales/effets des médicaments et des substances chimiques , Cellules épithéliales/métabolismeRÉSUMÉ
BACKGROUND: Heat-labile uracil-DNA glycosylase (HL-UDG) is commonly employed to eliminate carry-over contamination in DNA amplifications. However, the prevailing HL-UDG is markedly inactivated at 50°C, rendering it unsuitable for specific one-step RT-qPCR protocols utilizing reverse transcriptase at an optimal temperature of 42°C. OBJECTIVE: This study aimed to explore novel HL-UDG with lower inactivation temperature and for recombinant expression. METHODS: The gene encoding an HL-UDG was cloned from the cold-water fish rainbow trout (Oncorhynchus mykiss) and expressed in Escherichia coli with high yield. The thermostability of this enzyme and other enzymatic characteristics were thoroughly examined. The novel HL-UDG was then applied for controlling carry-over contamination in one-step RT-qPCR. RESULTS: This recombinantly expressed truncated HL-UDG of rainbow trout (OmUDG) exhibited high amino acids similarity (84.1% identity) to recombinant Atlantic cod UDG (rcUDG) and was easily denatured at 40°C. The optimal pH of OmUDG was 8.0, and the optimal concentrations of both Na+ and K+ were 10 mM. Since its inactivation temperature was lower than that of rcUDG, the OmUDG could be used to eliminate carry-over contamination in one-step RT-qPCR with moderate reverse transcription temperature. CONCLUSION: We successfully identified and recombinantly expressed a novel HL-UDG with an inactivation temperature of 40°C. It is suitable for eliminating carry-over contamination in one-step RT-qPCR.
Sujet(s)
Température élevée , Oncorhynchus mykiss , Uracil-DNA glycosidase , Oncorhynchus mykiss/génétique , Animaux , Uracil-DNA glycosidase/métabolisme , Uracil-DNA glycosidase/génétique , Uracil-DNA glycosidase/composition chimique , Stabilité enzymatique , Protéines recombinantes/génétique , Protéines recombinantes/composition chimique , Protéines recombinantes/métabolisme , Escherichia coli/génétique , Protéines de poisson/génétique , Protéines de poisson/composition chimique , Protéines de poisson/métabolisme , Réaction de polymérisation en chaine en temps réel/méthodes , Clonage moléculaireRÉSUMÉ
Improving feed utilization efficiency is a challenge in aquaculture. Therefore, we developed an indirect benchmark to use in selecting trout for improved efficiency of feed utilization on plant protein (soy)-based diets, with the long-term goal of reducing the cost of commercial trout production. We used a four-part integrative approach to identify feed efficient individuals among 1595 fish coming from 12 genetically selected families by establishing the phenotypic relationship between feed conversion ratio (FCR) and body weight variations using compensatory feeding regimes. Additionally, we examined the nutritional composition of fish filet for each efficiency phenotype during the compensatory regimen. Our findings showed that the fish with the lowest weight loss during a feed deprivation period and the highest weight gain during the refeeding period (FD-/RF +) demonstrated the lowest FCR (FCR = 0.99) and consisted of individuals from several lines. This finding confirms the possibility of improving feed efficiency in mixed lines. Although feeding period has an effect on nutritional composition of fillet, such selection criteria did not show an effect on groups. Overall, successful selection for the improvement of feed efficiency will have a broad application to commercial fish selective breeding programs, leading to increased aquaculture sustainability in the long run.
Sujet(s)
Oncorhynchus mykiss , Humains , Animaux , Oncorhynchus mykiss/génétique , Protéines végétales/génétique , Régime alimentaire , Reproduction sélective , Poids/génétique , Aliment pour animaux/analyseRÉSUMÉ
BACKGROUND: Evolutionary processes leave footprints along the genome over time. Highly homozygous regions may correspond to positive selection of favorable alleles, while maintenance of heterozygous regions may be due to balancing selection phenomena. We analyzed data from 176 fish from four disconnected domestic rainbow trout populations that were genotyped using a high-density Axiom Trout genotyping 665K single nucleotide polymorphism array, including 20 from the US and 156 from three French lines. Using methods based on runs of homozygosity and extended haplotype homozygosity, we detected signatures of selection in these four populations. RESULTS: Nine genomic regions that included 253 genes were identified as being under positive selection in all four populations Most were located on chromosome 2 but also on chromosomes 12, 15, 16, and 20. In addition, four heterozygous regions that contain 29 genes that are putatively under balancing selection were also shared by the four populations. These were located on chromosomes 10, 13, and 19. Regardless of the homozygous or heterozygous nature of the regions, in each region, we detected several genes that are highly conserved among vertebrates due to their critical roles in cellular and nuclear organization, embryonic development, or immunity. We identified new candidate genes involved in rainbow trout fitness, as well as 17 genes that were previously identified to be under positive selection, 10 of which in other fishes (auts2, atp1b3, zp4, znf135, igf-1α, brd2, col9a2, mrap2, pbx1, and emilin-3). CONCLUSIONS: Using material from disconnected populations of different origins allowed us to draw a genome-wide map of signatures of positive selection that are shared between these rainbow trout populations, and to identify several regions that are putatively under balancing selection. These results provide a valuable resource for future investigations of the dynamics of genetic diversity and genome evolution during domestication.
Sujet(s)
Oncorhynchus mykiss , Animaux , Oncorhynchus mykiss/génétique , Polymorphisme de nucléotide simple , Génome , Cartographie chromosomique , GénotypeRÉSUMÉ
The aim of this study was to produce mutant strains of Bacillus subtilis with high probiotic performance for use in the aquaculture of rainbow trout Oncorhynchus mykiss. The main strain of B. subtilis (MS) was irradiated with gamma rays (5.3 KGy). Subsequently, the B. subtilis mutant strain no. 45 (MS. 45) was selected for bacterial growth performance, resistance to acidic conditions, resistance to bile salts and antibacterial activity against Aeromonas hydrophila and Pseudomonas fluorescens. After 60 days, the rainbow trout (70.25 ± 3.89 g) fed with MS. 45 and MS were exposed to hypoxia stress (dissolved oxygen = 2 ppm). Subsequently, immune indices (lysozyme, bacterial activity and complement activity), hematological indices [hematocrit, hemoglobin, WBC, RBC, mean corpuscular volume (MCV)] and antioxidant factors (T-AOC, SOD and MDA)) were analyzed after and before hypoxia exposure. The expression of immunological genes (IFN-γ, TNF-α, IL-1ß, IL-8) in the intestine and the expression of hypoxia-related genes (HIF-1α, HIF-2α, FIH1) in the liver were compared between the different groups under hypoxia and normoxia conditions. Growth, immunological and antioxidant indices improved in group MS. 45 compared to the other groups. Stress indices and associated immunologic and hypoxia expressions under hypoxia and normoxia conditions improved in MS. 45 compared to the other groups. This resulted in improved growth, immunity and stress responses in fish fed with the microbial supplement of MS. 45 (P < 0.05) under hypoxia and normoxia conditions, (P < 0.05), resulting in a significant improvement in trout aquaculture.
Sujet(s)
Maladies des poissons , Oncorhynchus mykiss , Probiotiques , Animaux , Régime alimentaire , Oncorhynchus mykiss/génétique , Antioxydants/métabolisme , Bacillus subtilis/métabolisme , Probiotiques/pharmacologie , Aquaculture , Hypoxie , Aliment pour animaux/analyse , Maladies des poissons/microbiologieRÉSUMÉ
The hypothalamus is a key integrating center that is involved in the initiation of the corticosteroid stress response, and in regulating nutrient homeostasis. Although cortisol, the principal glucocorticoid in humans and teleosts, plays a central role in feeding regulation, the mechanisms are far from clear. We tested the hypothesis that the metabolic changes to cortisol exposure signal an energy excess in the hypothalamus, leading to feeding suppression during stress in fish. Rainbow trout (Oncorhynchus mykiss) were administered a slow-release cortisol implant for 3 days, and the metabolite profiles in the plasma, hypothalamus, and the rest of the brain were assessed. Also, U-13C-glucose was injected into the hypothalamus by intracerebroventricular (ICV) route, and the metabolic fate of this energy substrate was followed in the brain regions by metabolomics. Chronic cortisol treatment reduced feed intake, and this corresponded with a downregulation of the orexigenic gene agrp, and an upregulation of the anorexigenic gene cart in the hypothalamus. The U-13C-glucose-mediated metabolite profiling indicated an enhancement of glycolytic flux and tricarboxylic acid intermediates in the rest of the brain compared with the hypothalamus. There was no effect of cortisol treatment on the phosphorylation status of AMPK or mechanistic target of rapamycin in the brain, whereas several endogenous metabolites, including leucine, citrate, and lactate were enriched in the hypothalamus, suggesting a tissue-specific metabolic shift in response to cortisol stimulation. Altogether, our results suggest that the hypothalamus-specific enrichment of leucine and the metabolic fate of this amino acid, including the generation of lipid intermediates, contribute to cortisol-mediated feeding suppression in fish.NEW & NOTEWORTHY Elevated cortisol levels during stress suppress feed intake in animals. We tested whether the feed suppression is associated with cortisol-mediated alteration in hypothalamus metabolism. The brain metabolome revealed a hypothalamus-specific metabolite profile suggesting nutrient excess. Specifically, we noted the enrichment of leucine and citrate in the hypothalamus, and the upregulation of pathways involved in leucine metabolism and fatty acid synthesis. This cortisol-mediated energy substrate repartitioning may modulate the feeding/satiety centers leading to the feeding suppression.
Sujet(s)
Oncorhynchus mykiss , Animaux , Humains , Oncorhynchus mykiss/génétique , Oncorhynchus mykiss/métabolisme , Hydrocortisone/métabolisme , Leucine/métabolisme , Hypothalamus/métabolisme , Encéphale/métabolisme , Glucose/pharmacologie , Glucose/métabolisme , Citrates/métabolisme , Citrates/pharmacologieRÉSUMÉ
Alternative splicing (AS) plays an important role in various physiological processes in eukaryotes, such as the stress response. However, patterns of AS events remain largely unexplored during salinity acclimation in fishes. In this study, we conducted AS analysis using RNA-seq datasets to explore splicing patterns in the gill tissues of rainbow trout exposed to altered salinity environments, ranging from 0 (T0) to 30 (T30). The results revealed 1441, 351, 483, 1051 and 1049 differentially alternatively spliced (DAS) events in 5 pairwise comparisons, including T6 vs. T0, T12 vs. T0, T18 vs. T0, T24 vs. T0, and T30 vs. T0, respectively. These DAS events were derived from 1290, 328, 444, 963 and 948 genes. Enrichment analysis indicated that these DAS genes were related to RNA splicing and processing. Among these, 14 DAS genes were identified as members of the large heterogeneous nuclear RNP (hnRNP) gene family. Alternative 3' splice site (A3SS), exon skipping (SE) and intron retention (RI) events resulted in the fragmentation or even loss of the functional RNA recognition motif (RRM) domains in hnrnpa0, hnrnp1a, hnrnp1b and hnrnpc genes. The incomplete RRM domains would hinder the interactions between hnRNP genes and pre-mRNAs. It would in turn influence the splicing patterns and mRNA stability of downstream target genes in response to salinity changes. The study provides insights into salinity acclimation in gill tissues of rainbow trout and serves as a significant reference on the osmoregulation mechanisms at post-transcription regulation levels in fish.