Microalgae and cyanobacteria as microbial substrate and their influence on the potential postbiotic capability of a bacterial probiotic.

Postbiotics are metabolic by-products from microorganisms that provide health benefits to the host. Their secretion can be influenced by various conditions affecting bacterial metabolism. This study presents a novel approach for producing potential postbiotics, specifically extracellular products (ECPs), from the probiotic strain Shewanella putrefaciens SpPdp11, grown under different culture conditions.

Identification of a Novel β-Defensin Gene in Gilthead Seabream (Sparus aurata).

The excessive use of antibiotics in aquaculture favors the natural selection of multidrug-resistant bacteria, and antimicrobial peptides (AMPs) could be a promising alternative to this problem. The most studied AMPs in teleost fish are piscidins, hepcidins, and β-defensins. In this work, we have found a new gene (defb2) encoding a type 2 β-defensin in the genome of gilthead seabream, a species chosen for its economic interest in aquaculture.

Fish HERC7: Phylogeny, Characterization, and Potential Implications for Antiviral Immunity in European Sea Bass.

E3 ubiquitin ligases, key components of the ubiquitin proteasome system, orchestrate protein degradation through ubiquitylation and profoundly impact cellular biology. Small HERC E3 ligases (HERC3-6) have diverse functions in mammals, including roles in spermatogenesis, protein degradation, and immunity. Until now, only mammals' HERC3, HERC5, and HERC6 are known to participate in immune responses, with major involvement in the antiviral response.

Synthetic antimicrobial Nkl and Dic peptides are immunomodulatory but only Dic peptide can be therapeutic against nodavirus infection.

Aquaculture is a prosperous economic sector threatened by viral infections. Among the viruses threatening fish culture, Betanodavirus (NNV) is extremely important in the Mediterranean Sea affecting to highly traded species as European sea bass. In this context, application of antimicrobial peptides (AMPs) has arisen as a potential biotechnological tool.

The susceptibility of shi drum juveniles to betanodavirus increases with rearing densities in a process mediated by neuroactive ligand-receptor interaction.

Nervous necrosis virus (NNV) is one of the greatest threats to Mediterranean aquaculture, infecting more than 170 fish species and causing mortalities up to 100% in larvae and juveniles of susceptible species. Intensive aquaculture implies stressed conditions that affect the welfare of fish and their ability to fight against infections. In fact, a higher susceptibility to NNV has been related to poor welfare conditions.

Transcriptional Evaluation of Neuropeptides, Hormones, and Tissue Repair Modulators in the Skin of Gilthead Sea Bream ( L.) Subjected to Mechanical Damage.

The skin of bony fish is the first physical barrier and is responsible for maintaining the integrity of the fish. Lesions make the skin vulnerable to potential infection by pathogens present in the aquatic environment. In this way, wound repair has barely been studied in gilthead sea bream.

Identification and functional characterization of fish IL-17 receptors suggest important roles in the response to nodavirus infection.

Unlabelled: Th17 is a lymphocyte T helper (Th) subpopulation relevant in the control and regulation of the immune response characterized by the production of interleukin (IL)-17. This crucial cytokine family acts through their binding to the IL-17 receptors (IL-17R), having up to six members. Although the biology of fish Th17 is well-recognized, the molecular and functional characterization of IL-17 and IL-17R has been limited.

Synthetic Antimicrobial Peptides Fail to Induce Leucocyte Innate Immune Functions but Elicit Opposing Transcriptomic Profiles in European Sea Bass and Gilthead Seabream.

Antimicrobial peptides (AMPs) are promising molecules in diverse fields, including aquaculture. AMPs possess lytic effects on a wide range of pathogens, resulting in a potential replacement for traditional antimicrobials in aquaculture. In addition, they also have modulatory effects on host immune responses.

Cytotoxic activity and gene expression during in vitro adaptive cell-mediated cytotoxicity of head-kidney cells from betanodavirus-infected European sea bass.

Cell-mediated cytotoxicity (CMC) is essential in eradicating virus-infected cells, involving CD8 T lymphocytes (CTLs) and natural killer (NK) cells, through the activation of different pathways. This immune response is well-studied in mammals but scarcely in teleost fish. Our aim was to investigate the adaptive CMC using head-kidney (HK) cells from European sea bass infected at different times with nodavirus (NNV), as effector cells, and the European sea bass brain cell line (DLB-1) infected with different NNV genotypes, as target cells.

Regulation and distribution of European sea bass perforins point to their role in the adaptive cytotoxic response against NNV.

Cell-mediated cytotoxicity is a complex immune mechanism that involves the release of several killing molecules, being perforin (PRF) one of the most important effector players. Perforin is synthesized by T lymphocytes and natural killer cells in mammals and responsible for the formation of pores on the target cell membrane during the killing process. Although perforin has been extensively studied in higher vertebrates, this knowledge is very limited in fish.

Application of transcriptomic profiling to investigate the toxicity mechanisms caused by dietary exposure of nanoplastics in fish.

Nowadays, nanoplastics (NPs) are one of the main concerns regarding plastic pollution. The increasing presence of plastic particles, fibers and fragments in the marine environment pose an additional risk to both, wild and cultured fish. Ingestion is the main mechanism by which particles are internalized.

Updating Our Knowledge on Fish Immunology.

Fish is the first group of vertebrates to appear during animal evolution [...

Effects of okra (Abelmoschus esculentus L.) leaves, fruits and seeds extracts on European sea bass (Dicentrarchus labrax) leukocytes, and their cytotoxic, bactericidal and antioxidant properties.

Okra, Abelmoschus esculentus L., is a popular vegetable crop with many bioactive compounds. The in vitro immunostimulant, cytotoxic, bactericidal and antioxidant activities of ethanolic extracts obtained from different parts of okra (leaves, fruits, and seeds) were studied.

Immunotoxicological effects of perfluorooctanesulfonic acid on European seabass are reduced by polyethylene microplastics.

Marine environments receive plastic waste, where it suffers a transformation process into smaller particles. Among them, microplastics (MPs; <5 mm) are ingested by aquatic organisms leading to negative effects on animal welfare. The interactions between MPs, contaminants and organisms are poorly understood.

Priming European Sea Bass Female Broodstock Improves the Antimicrobial Immunity of Their Offspring.

Acquiring immunocompetence is essential in the development of fish embryos, as they are exposed to environmental pathogens even before they are fertilized. Despite the importance of the antimicrobial function as the first line of defense against foreign microorganisms, little knowledge is available about its role in larval development. In vertebrates, transgenerational immune priming influences the acquisition of immunocompetence of specimens, regulating the selective allocation of nongenetic resources to their progeny and modulating their development.

Molecular characterization of the cytotoxic and regulatory T cell coreceptor (CRTAM), and its ligand CADM1, in the European seabass and gilthead seabream.

T cell activation is a multifaceted process that depends on the activation of the T cell receptor (TCR). However, other coreceptors are also strictly necessary to provide co-signals and modulate the immune response. However, to date, most of these coreceptors are unknown in fish or their information is very limited.

Immunity elicited by AMP-encoding plasmids fails to increase the protection of European sea bass against nodavirus.

Antimicrobial peptides (AMPs) are a potent arm of the innate immune system that can directly kill pathogens and induce immunomodulation. In the marine aquaculture, European sea bass (Dicentrarchus labrax L.) is one of the most prosperous species but is highly susceptible to nodavirus (NNV), which produces high rates of mortality in larvae and juvenile stages.

Induction and characterization of extracellular traps by gilthead seabream (Sparus aurata L.) head-kidney leucocytes.

The aim of this study was the induction and characterization of extracellular traps (ETs) produced by gilthead seabream (Sparus aurata L.) head-kidney leucocytes. The cells were incubated several times (10, 30, 60, 120, and 180 min) with different concentrations of the stimulants diluted in RPMI-1640 culture medium: RPMI-1640 (control), β-glucan from Saccharomyces cerevisiae (BG, 0-400 μg mL), lipopolysaccharide from Escherichia coli (LPS, 0-10 μg mL), calcium ionophore A23187 (CaI, 0-5 μg mL), Phorbol 12-myristate 13-acetate (PMA, 0-1000 ng mL) and polyinosinic-polycytidylic acid sodium salt (Poly I:C, 0-200 μg mL).

Two duplicated piscidin genes from gilthead seabream (Sparus aurata) with different roles in vitro and in vivo.

From the discovery of pleurocidin in skin mucus of winter flounder, many new related sequences have been found, forming a fish-exclusive family of antimicrobial peptides (AMP) called piscidin. Their mature peptides have a broad-spectrum antimicrobial activity and can be involved in the innate immune response. In the present work, two paralogous tripartite piscidin genes are formally described for the first time in gilthead seabream (Sparus aurata), an important marine farmed fish.

Profile of Innate Immunity in Gilthead Seabream Larvae Reflects Mortality upon Betanodavirus Reassortant Infection and Replication.

Historically, gilthead seabream () has been considered a fish species resistant to nervous necrosis virus (NNV) disease. Nevertheless, mortality in seabream hatcheries, associated with typical clinical signs of the viral encephalopathy and retinopathy (VER) disease has been confirmed to be caused by RGNNV/SJNNV reassortants. Because of this, seabream larvae at 37 and 86 days post-hatching (dph) were infected by immersion with RGNNV/SJNNV and SJNNV/RGNNV reassortants under laboratory conditions, and mortality, viral replication and immunity were evaluated.

Massive gene expansion of hepcidin, a host defense peptide, in gilthead seabream (Sparus aurata).

Host defense peptides (HDP) are among the most ancient immune molecules in animals and clearly reflect an ancestral evolutionary history involving pathogen-host interactions. Hepcidins are a very widespread family of HDPs among vertebrates and are especially diverse in teleosts. We have investigated the identification of new hepcidins in gilthead seabream (Sparus aurata), a fish farmed in the Mediterranean.

Nanoplastics Increase Fish Susceptibility to Infection and Reduce Antiviral Immune Responses.

Nanoplastics (NPs) might cause different negative effects on aquatic organisms at different biological levels, ranging from single cells to whole organisms, including cytotoxicity, reproduction, behavior or oxidative stress. However, the impact of NPs on disease resistance is almost unknown. The objective of this study was to assess whether exposure to 50 nm functionalized polystyrene NPs impacts fish susceptibility to viral diseases both in vitro and .

Severe Natural Outbreak of in Gilthead Seabream Produces Leukocyte Mobilization and Innate Immunity at the Gill Tissue.

The protozoan parasite causes marine white spot disease in a wide range of fish hosts, including gilthead seabream, a very sensitive species with great economic importance in the Mediterranean area. Thus, we aimed to evaluate the immunity of gilthead seabream after a severe natural outbreak of . Morphological alterations and immune cell appearance in the gills were studied by light microscopy and immunohistochemical staining.