First description of Vibrio ostreicida as putative causal agent of disease in Mediterranean mussel (Mytilus galloprovincialis) and development of a PCR protocol for its rapid diagnosis.

In April 2022, mussels (Mytilus galloprovincialis) cultivated in the Ebro River delta (Spain) were affected by a mortality episode, involving 25 % of individuals, observed at a water temperature of 18 °C. Mussel samples from this site (3 M) were analysed for the presence of potentially pathogenic bacteria, in parallel with those obtained from an area where no mortality was reported (3 N). From all samples, a total of 113 bacterial isolates were obtained.

First insights into bacterial and microalgal endosymbiont communities of various coral morphotypes from Maldives.

The Maldivian Archipelago is home to valuable coral reefs that have been extensively studied for their ecological diversity. However, the diversity of the microbiome in Maldivian corals remains largely unexplored. In this study, the microbiota compositions (including both algal endosymbionts and bacteria) were investigated for the first time across various coral morphotypes sampled in May 2022 from four Maldivian atolls (Ari, North Malé, South Malé, and Rasdhoo).

are a potential source of novel colistin-resistance genes in European coastal environments.

Colistin is a widespread last resort antibiotic for treatment of multidrug-resistant bacteria. The recent worldwide emergence of colistin resistance (Col-R) conferred by -1 in human pathogens has raised concern, but the putative sources and reservoirs of novel genes in the marine environment remain underexplored. We observed a high prevalence of Col-R, particularly in isolated from European coastal waters by using the same cohorts of oysters as bioaccumulators in three sites across Europe.

Impact of ocean warming on early development of the Mediterranean mussel Mytilus galloprovincialis: Effects on larval susceptibility to potential vibrio pathogens.

In a global change scenario, ocean warming and pathogen infection can occur simultaneously in coastal areas, threatening marine species. Data are shown on the impact of temperature on early larvae of the Mediterranean mussel Mytilus galloprovincialis. Increasing temperatures (18-20-22 °C) altered larval phenotypes at 48 hpf and affected gene expression from eggs to 24 and 48 hpf, with shell biogenesis related genes among the most affected.

Genome-resolved metagenomics revealed novel microbial taxa with ancient metabolism from macroscopic microbial mat structures inhabiting anoxic deep reefs of a Maldivian Blue Hole.

Blue holes are vertical water-filled openings in carbonate rock that exhibit complex morphology, ecology, and water chemistry. In this study, macroscopic microbial mat structures found in complete anoxic conditions in the Faanu Mudugau Blue Hole (Maldives) were studied by metagenomic methods. Such communities have likely been evolutionary isolated from the surrounding marine environment for more than 10,000 years since the Blue Hole formation during the last Ice Age.

Polyester Microfibers Exposure Modulates Hemolymph Microbiome.

Microplastic (MP) contamination in the aquatic environment is a cause of concern worldwide since MP can be taken up by different organisms, altering different biological functions. In particular, evidence is accumulating that MP can affect the relationship between the host and its associated microbial communities (the microbiome), with potentially negative health consequences. Synthetic microfibers (MFs) represent one of the main MPs in the marine environment, which can be accumulated by filter-feeding invertebrates, such as bivalves, with consequent negative effects and transfer through the food chain.

Pan-Genome Provides Insights into Vibrio Evolution and Adaptation to Deep-Sea Hydrothermal Vents.

This study delves into the genomic features of 10 Vibrio strains collected from deep-sea hydrothermal vents in the Pacific Ocean, providing insights into their evolutionary history and ecological adaptations. Through sequencing and pan-genome analysis involving 141 Vibrio species, we found that deep-sea strains exhibit larger genomes with unique gene distributions, suggesting adaptation to the vent environment. The phylogenomic reconstruction of the investigated isolates revealed the presence of 2 main clades: The first is monophyletic, consisting exclusively of Vibrio alginolyticus, while the second forms a monophyletic clade comprising both Vibrio antiquarius and Vibrio diabolicus species, which were previously isolated from deep-sea vents.

Plankton and marine aggregates as transmission vectors for V. aestuarianus 02/041 infecting the pacific oyster Crassostrea gigas.

Vibrio aestuarianus is a bacterium related to mass mortality outbreaks of the Pacific oyster, Crassostrea gigas in Europe. In this study, the role of different planktonic substrates (phytoplankton cells, marine aggregates and chitin fragments) in mediating V. aestuarianus 02/041 infection of oysters was evaluated by controlled infection experiments.

Soluble mediators of innate immunity in annelids and bivalve mollusks: A mini-review.

Annelids and mollusks, both in the superphylum of Lophotrochozoa (Bilateria), are important ecological groups, widespread in soil, freshwater, estuarine, and marine ecosystems. Like all invertebrates, they lack adaptive immunity; however, they are endowed with an effective and complex innate immune system (humoral and cellular defenses) similar to vertebrates. The lack of acquired immunity and the capacity to form antibodies does not mean a lack of specificity: invertebrates have evolved genetic mechanisms capable of producing thousands of different proteins from a small number of genes, providing high variability and diversity of immune effector molecules just like their vertebrate counterparts.

Responses of Mytilus galloprovincialis to challenge with environmental isolates of the potential emerging pathogen Malaciobacter marinus.

Bacteria of the Arcobacter-like spp. represent emerging foodborne zoonotic pathogens in humans and animals. Their increasing presence in seafood, suggesting higher occurrence in seawater due to marine pollution, is raising some environmental concern.

Methodological Approaches To Assess Innate Immunity and Innate Memory in Marine Invertebrates and Humans.

Assessing the impact of drugs and contaminants on immune responses requires methodological approaches able to represent real-life conditions and predict long-term effects. Innate immunity/inflammation is the evolutionarily most widespread and conserved defensive mechanism in living organisms, and therefore we will focus here on immunotoxicological methods that specifically target such processes. By exploiting the conserved mechanisms of innate immunity, we have examined the most representative immunotoxicity methodological approaches across living species, to identify common features and human proxy models/assays.

Comparison of Different Commercial Nanopolystyrenes: Behavior in Exposure Media, Effects on Immune Function and Early Larval Development in the Model Bivalve .

In the absence of standard methods for the detection/quantification of nanoplastics (NPs) in environmental samples, commercial nanopolymers are utilized as proxies for toxicity testing and environmental risk assessment. In marine species, a considerable amount of data are now available on the effects of nanopolystyrene (PS-NPs) of different size/surface characteristics. In this work, amino modified PS-NPs (PS-NH) (50 and 100 nm), purchased from two different companies, were compared in terms of behavior in exposure media and of biological responses, from molecular to organism level, in the model marine bivalve .

Cross-Species Comparisons of Nanoparticle Interactions with Innate Immune Systems: A Methodological Review.

Many components of the innate immune system are evolutionarily conserved and shared across many living organisms, from plants and invertebrates to humans. Therefore, these shared features can allow the comparative study of potentially dangerous substances, such as engineered nanoparticles (NPs). However, differences of methodology and procedure between diverse species and models make comparison of innate immune responses to NPs between organisms difficult in many cases.

A deep-sea bacterium related to coastal marine pathogens.

Evolution of virulence traits from adaptation to environmental niches other than the host is probably a common feature of marine microbial pathogens, whose knowledge might be crucial to understand their emergence and pathogenetic potential. Here, we report genome sequence analysis of a novel marine bacterial species, Vibrio bathopelagicus sp. nov.

Immunological Responses of Marine Bivalves to Contaminant Exposure: Contribution of the -Omics Approach.

The increasing number of data studies on the biological impact of anthropogenic chemicals in the marine environment, together with the great development of invertebrate immunology, has identified marine bivalves as a key invertebrate group for studies on immunological responses to pollutant exposure. Available data on the effects of contaminants on bivalve immunity, evaluated with different functional and molecular endpoints, underline that individual functional parameters (cellular or humoral) and the expression of selected immune-related genes can distinctly react to different chemicals depending on the conditions of exposure. Therefore, the measurement of a suite of immune biomarkers in hemocytes and hemolymph is needed for the correct evaluation of the overall impact of contaminant exposure on the organism's immunocompetence.

Functional and Morphological Changes Induced in Hemocytes by Selected Nanoparticles.

Nanoparticles (NPs) show various properties depending on their composition, size, and surface coating, which shape their interactions with biological systems. In particular, NPs have been shown to interact with immune cells, that represent a sensitive surveillance system of external and internal stimuli. In this light, in vitro models represent useful tools for investigating nano-bio-interactions in immune cells of different organisms, including invertebrates.

Conservation of Cell Communication Systems in Invertebrate Host-Defence Mechanisms: Possible Role in Immunity and Disease.

Innate immunity is continuously revealing multiple and highly conserved host-defence mechanisms. Studies on mammalian immunocytes are showing different communication systems that may play a role in coordinating innate immune responses also in invertebrates. Extracellular traps (ETs) are an immune response by which cells release net-like material, including DNA, histones and proteins.

Impact of nanoplastics on hemolymph immune parameters and microbiota composition in Mytilus galloprovincialis.

Ocean contamination by micro- and nanoplastics represents a potential threat to marine biota, from bacterial communities to higher organisms. In this work, the effect of in vivo exposure of Mytilus galloprovincialis to amino modified nanopolystyrene (PS-NH) (10 μg/L, 96 h) on hemolymph immune parameters and microbiota composition were investigated. Nanoplastics significantly affected immune parameters (decreased phagocytosis, increased ROS and lysozyme activity, inhibition of NO production).

Addressing Nanomaterial Immunosafety by Evaluating Innate Immunity across Living Species.

The interaction of a living organism with external foreign agents is a central issue for its survival and adaptation to the environment. Nanosafety should be considered within this perspective, and it should be examined that how different organisms interact with engineered nanomaterials (NM) by either mounting a defensive response or by physiologically adapting to them. Herein, the interaction of NM with one of the major biological systems deputed to recognition of and response to foreign challenges, i.

Exposure to TiO nanoparticles induces shifts in the microbiota composition of Mytilus galloprovincialis hemolymph.

It is now recognized that host microbiome, the community of microorganisms that colonize the animal body (e.g. microbiota) and their genomes, play an important role in the health status of all organisms, from nutrient processing to protection from disease.

Microplastic exposure and effects in aquatic organisms: A physiological perspective.

The impact of microplastics (MPs) on aquatic life, given their ubiquitous presence in the water compartment, represents a growing concern. Consistently, scientific knowledge is advancing rapidly, although evidence on actual adverse effects is still highly fragmented. This paper summarizes the recent literature on MP impacts on aquatic organisms in an attempt to link routes of uptake, possible alterations of physiological processes, and outcomes at different levels of biological organization.

Responses of Mytilus galloprovincialis to challenge with the emerging marine pathogen Vibrio coralliilyticus.

Vibrio coralliilyticus has emerged as a coral pathogen of concern throughout the Indo-Pacific reef. The interest towards understanding its ecology and pathogenic potential has increased since V. coralliilyticus was shown to be strongly virulent also for other species; in particular, it represents a serious threat for bivalve aquaculture, being one of the most important emerging pathogen responsible for oyster larval mortalities worldwide.

SCHeMA EU Project Summer School Report (Bilbao June 16 - 17, 2016).

This conference report describes the training activities that took place in the frame of the Integrated in Situ Chemical MApping probe (SCHeMA) summer school organized from the 14th to the 16th of June 2016 in Bilbao (Spain).