Unravelling turbot () resistance to : transcriptomic insights from two full-sibling families with divergent susceptibility.

Introduction: Furunculosis, caused by the gram-negative bacterium subsp. , remains a significant threat to turbot () aquaculture. Identifying genetic backgrounds with enhanced disease resistance is critical for improving aquaculture health management, reducing antibiotic dependency, and mitigating economic losses.

Characterization of a fish-specific immunoglobulin-like domain-containing protein (Igldcp) in zebrafish (Danio rerio) induced after nodavirus infection.

One of the most highly induced genes in zebrafish (Danio rerio) larvae after infection with the nodavirus red-spotted grouper nervous necrosis virus (RGNNV) was a member of the immunoglobulin superfamily (IgSF), which has remained uncharacterized and erroneously annotated in zebrafish and other fish species as galectin 17 (lgals17). We characterized this gene and named it immunoglobulin (Ig)-like domain-containing protein (igldcp), a new member of the IgSF that does not possess orthologs in mammals. Igldcp expression is induced by viral infection and it belongs to the group of interferon-stimulated genes (ISGs).

Transcriptomic analysis of turbot (Scophthalmus maximus) treated with zymosan a reveals that lncRNAs and inflammation-related genes mediate the protection conferred against Aeromonas salmonicida.

Aeromonas salmonicida is one of the most harmful pathogens in finfish aquaculture worldwide. Immunostimulants such as β-glucans are used to enhance the immunity of cultured fish. However, their effects on fish physiology are not completely understood.

RNA-Seq analysis of juvenile gilthead sea bream (Sparus aurata) provides some clues regarding their resistance to the nodavirus RGNNV genotype.

Gilthead sea bream (Sparus aurata) is considered an asymptomatic carrier for the nodavirus genotype affecting European sea bass (Dicentrarchus labrax), RGNNV. Only larvae and juveniles of sea bream have been found to be susceptible to the RGNNV/SJNNV reassortant. Nevertheless, the molecular bases of the high resistance of sea bream against RGNNV are not known, and the overall transcriptome response to the virus remains unexplored.

An environmentally relevant concentration of antibiotics impairs the immune system of zebrafish () and increases susceptibility to virus infection.

In this work, we analysed the transcriptome and metatranscriptome profiles of zebrafish exposed to an environmental concentration of the two antibiotics most frequently detected in European inland surface water, sulfamethoxazole (SMX) and clarithromycin (CLA). We found that those animals exposed to antibiotics (SMX+CLA) for two weeks showed a higher bacterial load in both the intestine and kidney; however, significant differences in the relative abundance of certain bacterial classes were found only in the intestine, which also showed an altered fungal profile. RNA-Seq analysis revealed that the complement/coagulation system is likely the most altered immune mechanism, although not the only one, in the intestine of fish exposed to antibiotics, with numerous genes inhibited compared to the control fish.

Transcriptome and Genome Analyses Applied to Aquaculture Research.

The Special Issue "Transcriptome and Genome Analyses Applied to Aquaculture Research" had great success among the researchers specialized in different fields of aquaculture [...

Editorial of Special Issue "The 2nd Edition: Vaccines for Aquaculture".

The Special Issue "Vaccines for Aquaculture" of the journal had a great success among fish immunologists, with 17 published manuscripts [...

The Immune System of Marine Organisms as Source for Drugs against Infectious Diseases.

The high proliferation of microorganisms in aquatic environments has allowed their coevolution for billions of years with other living beings that also inhabit these niches. Among the different existing types of interaction, the eternal competition for supremacy between the susceptible species and their pathogens has selected, as part of the effector division of the immune system of the former ones, a vast and varied arsenal of efficient antimicrobial molecules, which is highly amplified by the broad biodiversity radiated, above any others, at the marine habitats. At present, the great recent scientific and technological advances already allow the massive discovery and exploitation of these defense compounds for therapeutic purposes against infectious diseases of our interest.

Zebrafish as a Vertebrate Model for Studying Nodavirus Infections.

Nervous necrosis virus (NNV) is a neurotropic pathogenic virus affecting a multitude of marine and freshwater fish species that has a high economic impact on aquaculture farms worldwide. Therefore, the development of new tools and strategies aimed at reducing the mortality caused by this virus is a pivotal need. Although zebrafish is not considered a natural host for NNV, the numerous experimental advantages of this species make zebrafish an attractive model for studying different aspects of the disease caused by NNV, viral encephalopathy and retinopathy (VER).

Comprehensive transcriptome profiling and functional analysis of the meagre (Argyrosomus regius) immune system.

Meagre (Argyrosomus regius) belongs to the family Sciaenidae and is a promising candidate for Mediterranean aquaculture diversification. As a relatively recent species in aquaculture, the physiological consequences of the immune system activation in meagre are understudied. Spleen, as a primary lymphoid organ has an essential role in meagre immune and inflammatory responses.

Acute Inflammation Induces Neuroendocrine and Opioid Receptor Genes Responses in the Seabass Brain.

In fish, as observed in mammals, any stressful event affects the immune system to a larger or shorter extent. The neuroendocrine-immune axis is a bi-directional network of mobile compounds and their receptors that are shared between both systems (neuroendocrine and immune) and that regulate their respective responses. However, how and to what extent immunity modulates the neuroendocrine system is not yet fully elucidated.

Surgical face masks as a source of emergent pollutants in aquatic systems: Analysis of their degradation product effects in Danio rerio through RNA-Seq.

Surgical face masks are the most popularised and effective personal equipment for protecting public health during the COVID-19 pandemic. They are composed of plastic polymer fibres with a large amount of inorganic and organic compounds that can be released into aquatic environments through degradation processes. This source of microplastics and inorganic and organic substances could potentially impact aquatic organisms.

Differential Expression of Long Non-Coding RNA (lncRNA) in Mediterranean Mussel () Hemocytes under Immune Stimuli.

The Mediterranean mussel is one of the most economically relevant bivalve mollusk species in Europe and China. The absence of massive mortalities and their resistance to pathogens affecting other cultured bivalves has been under study in recent years. The transcriptome response of this species to different immune stimuli has been extensively studied, and even the complexity of its genome, which has recently been sequenced, has been suggested as one of the factors contributing to this resistance.

Characterization of the turbot (Scophthalmus maximus) interleukin-18: Identification of splicing variants, phylogeny, synteny and expression analysis.

Interleukin-18 (IL-18) is a pro-inflammatory cytokine that belongs to the interleukin-1 (IL-1) family of cytokines. As occurs with IL-1β, it is synthetized as an inactive precursor peptide that is mainly processed by the cysteine protease caspase-1 in the inflammasome complex. In mammals, and in collaboration with IL-12, it has been described as an important cytokine controlling the Th1-mediated immune responses through the induction of IFN-γ.

Stimulation of Hemocytes With Different Immune Challenges Induces Differential Transcriptomic, miRNomic, and Functional Responses.

Mediterranean mussels () are marine bivalve molluscs with high resilience to biotic and abiotic stress. This resilience is one of the reasons why this species is such an interesting model for studying processes such as the immune response. In this work, we stimulated mussel hemocytes with poly I:C, β-glucans, and LPS and then sequenced hemocyte mRNAs (transcriptome) and microRNAs (miRNome) to investigate the molecular basis of the innate immune responses against these pathogen-associated molecular patterns (PAMPs).

An integrative toxicogenomic analysis of plastic additives.

In developed countries, contact with plastics is constant. Plastics contain a vast number of additives such as plasticisers, stabilisers, antioxidants, flame retardants, etc., that can impact human health.

Interactions between the Parasite and the Immune System of the Turbot . A Transcriptomic Analysis.

The present study analyses the interactions between (a ciliate parasite that causes high mortalities in cultured flatfish) and the peritoneal cells of the turbot during an experimental infection. The transcriptomic response was evaluated in the parasites and in the fish peritoneal cells, at 1, 2 and 4 h post-infection (hpi) in turbot injected intraperitoneally (ip) with 10 ciliates and at 12 and 48 hpi in turbot injected ip with 10 ciliates. Numerous genes were differentially expressed (DE) in , relative to their expression in control ciliates (0 hpi): 407 (369 were up-regulated) at 1 hpi, 769 (415 were up-regulated) at 2 hpi and 507 (119 were up-regulated) at 4 hpi.

Size matters: Zebrafish (Danio rerio) as a model to study toxicity of nanoplastics from cells to the whole organism.

The contamination of the aquatic environment by plastic nanoparticles is becoming a major concern due to their potential adverse effects in aquatic biota. Therefore, in-depth knowledge of their uptake, trafficking and effects at cellular and systemic levels is essential to understand their potential impacts for aquatic species. In this work, zebrafish (Danio rerio) was used as a model and our aims were: i) to determine the distribution, uptake, trafficking, degradation and genotoxicity of polystyrene (PS) NPs of different sizes in a zebrafish cell line; ii) to study PS NPs accumulation, migration of immune cells and genotoxicity in larvae exposed to PS NPs; and iii) to assess how PS NPs condition the survival of zebrafish larvae exposed to a pathogen and/or how they impact the resistance of an immunodeficient zebrafish.

Potential Involvement of lncRNAs in the Modulation of the Transcriptome Response to Nodavirus Challenge in European Sea Bass ( L.).

Long noncoding RNAs (lncRNAs) are being increasingly recognised as key modulators of various biological mechanisms, including the immune response. Although investigations in teleosts are still lagging behind those conducted in mammals, current research indicates that lncRNAs play a pivotal role in the response of fish to a variety of pathogens. During the last several years, interest in lncRNAs has increased considerably, and a small but notable number of publications have reported the modulation of the lncRNA profile in some fish species after pathogen challenge.

RNA-Seq analysis of European sea bass (Dicentrarchus labrax L.) infected with nodavirus reveals powerful modulation of the stress response.

Nodavirus, or nervous necrosis virus (NNV), is the causative agent of viral encephalopathy and retinopathy (VER), a severe disease affecting numerous fish species worldwide. European sea bass, a cultured species of great economic importance, is highly susceptible to the disease. To better understand the response of this organism to NNV, we conducted RNA-Seq analysis of the brain and head kidney from experimentally infected and uninfected sea bass juveniles at 24 and 72 hours post-infection (hpi).

Zebrafish Genes Play Relevant but Distinct Roles in Antiviral Immunity.

The PTEN (phosphatase and TENsin homolog on chromosome 10) gene encodes a bifunctional phosphatase that acts as a tumor suppressor. However, PTEN has been implicated in different immune processes, including autophagy, inflammation, regulation of natural killer (NK) cell cytolytic activity and type I interferon responses. Unlike mammals, zebrafish possess two genes ( and ).

Conserved function of zebrafish (Danio rerio) Gdf15 as a sepsis tolerance mediator.

GDF15 is frequently detected in patients suffering from various diseases, especially those associated with pro-inflammatory processes and/or metabolic disorders. Accordingly, sepsis, whose major complications are related to metabolic alterations and systemic inflammation, significantly increases the secretion of GDF15. Indeed, this cytokine could be considered a marker of sepsis severity.

RNA-Seq analysis reveals that spring viraemia of carp virus induces a broad spectrum of PIM kinases in zebrafish kidney that promote viral entry.

PIM kinases are a family of serine/threonine protein kinases that potentiate the progression of the cell cycle and inhibit apoptosis. Because of this, they are considered to be proto-oncogenes, and they represent an interesting target for the development of anticancer drugs. In mammals, three PIM kinases exist (PIM-1, PIM-2 and PIM-3), and different inhibitors have been developed to block their activity.

Zebrafish C-reactive protein isoforms inhibit SVCV replication by blocking autophagy through interactions with cell membrane cholesterol.

In the present work, the mechanisms involved in the recently reported antiviral activity of zebrafish C-reactive protein-like protein (CRP1-7) against the spring viraemia of carp rhabdovirus (SVCV) in fish are explored. The results neither indicate blocking of the attachment or the binding step of the viral replication cycle nor suggest the direct inhibition of G protein fusion activity or the stimulation of the host's interferon system. However, an antiviral state in the host is induced.

Antiviral activity of palmitic acid via autophagic flux inhibition in zebrafish (Danio rerio).

Fatty acids (FAs) are key elements that affect not only growth but also different immune functions, and therefore, nutrition is important for growing healthy fish. Zebrafish (Danio rerio) is a good model for assessing the beneficial effects of immunostimulants, including FAs, before applying them in aquaculture. Accordingly, this study evaluated the effects of palmitic acid (PA) treatment on different immune parameters of zebrafish and on the mortality caused by the spring viremia of carp virus (SVCV).