Characterization of a novel antioxidant byssal protein from Mytilus coruscus foot.

Mussel byssal proteins are of biomimetic importance for the development of novel underwater bio-adhesive agents. It is important to maintain a reduced state during the process of byssus adhesion. There are 19 mussel foot proteins (MFPs) have been reported in previous studies, among which only MFP-6 had been confirmed as an antioxidant protein in mussel byssus due to the function of cysteines, and playing an essential role in the redox balance of mussel byssus during adhesion process. Although the other four MFPs (MFP-16 ~ MFP-19) also have abundant cysteines, their function is still unknown. In this study, a novel mussel foot protein, named MFP-20, was identified from Mytilus coruscus foot. The sequential features, expression profile, and function of recombinant MFP-20 were verified. The results showed that MFP-20 has more abundant cysteines than other MFPs, the relative expression of mfp-20 was upregulated in Fe3+ stress and low pH seawater. In addition, different adhesive substrates induced significant changes of expression level of mfp-20. Furthermore, rMFP-20 showed strong antioxidant capacity in the DPPH assay, and the abundant cysteines in its sequence may play vital roles in the antioxidation activity. Our findings revealed the possible function of MFP-20 with a totally different sequence from the reported MFP-6 and provided new clues for exploring the redox balance of mussel byssus during the adhesion process.

Effect of the farming site and harvest time on the nutritional, elemental and volatile profile of mussels: A comprehensive analysis of the PDO 'Cozza di Scardovari'.

This study comprehensively characterised a protected designation of origin mussel 'Cozza di Scardovari' (Mytilus galloprovincialis) by examining how it is affected by the farming site (outer vs. inner area of the lagoon) and harvest time (21 April vs. 18 May vs. 16 June). Harvest time affected the marketable traits and fatty acid profile of mussels, whereas farming site scarcely affected marketable traits and mussel yields. Mussels from the inner area of the lagoon displayed a superior nutritional profile, including higher contents of proteins (7.8% vs. 7.4%; P < 0.05), lipids (1.2% vs. 1.0%; P < 0.001) and essential amino acids such as tryptophan (+24%; P < 0.05) and valine (+8%; P < 0.05), with a more favourable n-3/n-6 ratio (7.7 vs. 7.0; P < 0.001) than those from the close-to-sea area. Volatile organic compounds, mainly octanoic acid, dimethyl sulphide and 1-penten-3-ol, differed between farming sites within the same lagoon.

Microplastic contamination in marine mussels from the Atlantic coast of North Portugal and human risk of microplastic intake through mussel consumption.

Microplastic (MP) pollution has become a global concern due to its potential impacts on the environment, ecosystem services and human health. The goals of the present study were to document the MP contamination in wild specimens of Mytilus galloprovincialis sampled along the Atlantic coast of the North region of Portugal continental (NW Portuguese coast), and to estimate the human risk of MP intake (HRI) through the consumption of local mussels as seafood. Mussels were collected at four sampling sites along the NW Portuguese coast (40 mussels per site), and the whole soft body of each mussel was analysed for MP content. HRI estimates were based on the mean of MP items per wet weight of mussel analysed tissue (MP/g) and consumption habits. A total of 132 MP items were recovered from mussels. MP had diverse sizes (98-2690 µm) and colours. The most common shapes were fibres (39%) and pellets (36%). Five polymers were identified in the MP: polyethylene (50%), polystyrene (15%), poly(ethylene vinyl acetate) (14%), polyamide (12%) and polypropylene (9%). From the 160 analysed mussels, 55% had MP. The mean and standard error of the mean of mussel contamination ranged from 0.206 ± 0.067 and 0.709 ± 0.095 MP/g. Compared to estimates based on MP contamination in mussels from other areas and varied consumption habits, the HRI through the consumption of mussels from the NW Portuguese coast is relatively low.

Evaluation of the health of Mediterranean mussels (Mytilus galloprovincialis Lamarck, 1819) distributed in the Çanakkale strait, Turkey.

The observation of mortality in Mediterranean mussels (Mytilus galloprovincialis) distributed in the Çanakkale Strait in recent years was influential in developing the research question for this study. In this study, the presence of bacteria (Vibrio spp.) and parasites (Marteilia spp. and Haplosporidium spp.) in mussels collected from Kumkale, Kepez, and Umurbey stations in the Çanakkale Strait was investigated seasonally. Microbiological findings, histopathology, oxidative stress enzymes and their gene expressions, lipid peroxidation, lysosomal membrane stability, and changes in haemolymph were examined. In summer samples, both the defence system and the extent of damage were higher in gill tissue. In winter samples, enzyme activities and lipid peroxidation were found to be predominantly higher in digestive gland tissues. Histological examinations and Hemacolor staining revealed the presence of protozoan cysts, and for bacterial examination, molecular analysis performed after culturing revealed the presence of 7 Vibrio species. While the total numbers of heterotrophic bacteria detected in all samples were at acceptable levels, the predominance of Vibrio spp. numbers among the total heterotrophic bacteria detected in almost all samples were noteworthy. The total hemocyte count was calculated as 5.810(4)±0.58 (cells/mm3) in winter and 7.210(4)±1.03 (cells/mm3) in summer. These factors are considered to be possible causes of mussel mortality.

Uranium contamination of bivalve Mytilus galloprovincialis, speciation and localization.

Uranium is a natural radioelement (also a model for heavier actinides), but may be released through anthropogenic activities. In order to assess its environmental impact in a given ecosystem, such as the marine system, it is essential to understand its distribution and speciation, and also to quantify its bioaccumulation. Our objective was to improve our understanding of the transfer and accumulation of uranium in marine biota with mussels taken here as sentinel species because of their sedentary nature and ability to filter seawater. We report here on the investigation of uranium accumulation, speciation, and localization in Mytilus galloprovincialis using a combination of several analytical (Inductively Coupled Plasma Mass Spectrometry, ICP-MS), spectroscopic (X ray Absorption Spectroscopy, XAS, Time Resolved Laser Induced Fluorescence Spectroscopy, TRLIFS), and imaging (Transmission Electron Microscopy, TEM, µ-XAS, Secondary Ion Mass Spectrometry, SIMS) techniques. Two cohorts of mussels from the Toulon Naval Base and the Villefranche-sur-Mer location were studied. The measurement of uranium Concentration Factor (CF) values show a clear trend in the organs of M. galloprovincialis: hepatopancreas â‰« gill > body ≥ mantle > foot. Although CF values for the entire mussel are comparable for TNB and VFM, hepatopancreas values show a significant increase in those from Toulon versus Villefranche-sur-Mer. Two organs of interest were selected for further spectroscopic investigations: the byssus and the hepatopancreas. In both cases, U(VI) (uranyl) is accumulated in a diffuse pattern, most probably linked to protein complexing functions, with the absence of a condensed phase. While such speciation studies on marine organisms can be challenging, they are an essential step for deciphering the impact of metallic radionuclides on the marine biota in the case of accidental release. Following our assumptions on uranyl speciation in both byssus and hepatopancreas, further steps will include the inventory and identification of the proteins or metabolites involved.

Mussels (Mytilus spp.) in Svalbard contain microplastic particles in tissues: Implications for monitoring.

We examined the presence of microplastics in blue mussels Mytilus spp. from the intertidal zone of western Spitsbergen in Arctic Svalbard. The optical microscopy technique detected a total of 148 microplastics, with the highest concentration per mussel being 24 particles. Microplastics were found in 84% of the examined mussels. The microplastics ranged in size from <0.5 mm to 5 mm and consisted of fibers (83%), fragments (13%), plates (3%), and spherules (1%). The micro-Raman spectroscopy technique revealed four different types of polymers: polyethylene (67%), nylon-12 (17%), low-density polyethylene (11%), and polypropylene (5%). Our research shows that Arctic coastal waters are polluted with microplastics notwithstanding their remoteness. These findings suggest that microplastic contamination may harm marine life and coastal ecosystems and require further research into long-term environmental effects. We also indicate that intertidal mussels may be beneficial for monitoring microplastics because they can be collected without involving diving.

Evidence of internalized microplastics in mussel tissues detected by volumetric Raman imaging.

Microplastics are a global ecological concern due to their potential risk to wildlife and human health. Animals ingest microplastics, which can enter the trophic chain and ultimately impact human well-being. The ingestion of microplastics can cause physical and chemical damage to the animals' digestive systems, affecting their health. To estimate the risk to ecosystems and human health, it is crucial to understand the accumulation and localization of ingested microplastics within the cells and tissues of living organisms. However, analyzing this issue is challenging due to the risk of sample contamination, given the ubiquity of microplastics. Here, an analytical approach is employed to confirm the internalization of microplastics in cryogenic cross-sections of mussel tissue. Using 3D Raman confocal microscopy in combination with chemometrics, microplastics measuring 1 µm in size were detected. The results were further validated using optical and fluorescence microscopy. The findings revealed evidence of microplastics being internalized in the digestive epithelial tissues of exposed mussels (Mytilus galloprovincialis), specifically within the digestive cells forming digestive alveoli. This study highlights the need to investigate the internalization of microplastics in organisms like mussels, as it helps us understand the potential risks they pose to aquatic biota and ultimately to human health. By employing advanced imaging techniques, challenges associated with sample contamination can be overcome and valuable insights into the impact of microplastics on marine ecosystems and human consumers are provided.

Microplastics in marine mussels, biological effects and human risk of intake: A case study in a multi-stressor environment.

This study documented seasonal levels of microplastics (MPs) and biomarkers (condition index, neurotoxicity, energy, oxidative stress) in mussels (Mytilus galloprovincialis), and water physico-chemical parameters in the Douro estuary (NE Atlantic coast), and estimated the human risk of MP intake (HRI) through mussels. Mussel stress was determined through the Integrated Biomarker Response (IBR). HRI was estimated from mussel MP concentrations and consumer habits. MPs were mainly micro-fibres (72 %) with varied chemical composition. Seasonal MP means (±SEM) in mussels ranged from 0.111 ± 0.044 (spring) to 0.312 ± 0.092 MPs/g (summer). Seasonal variations of mussel stress (IBR: 1.4 spring to 9.7 summer) and MP concentrations were not related. MeO-BDEs, PBDEs, temperature, salinity and other factors likely contributed to mussel stress variation. HRI ranged from 2438 to 2650 MPs/year. Compared to the literature, MP contamination in mussels is low, as well as the human risk of MP intake through their consumption.

Physicochemical properties and antimicrobial activities of MytiLec-1, a member from the mytilectin family of mussels.

MytiLec-1, the recombinant form of a mussel lectin from Mytillus galloprovincialis, was purified by affinity chromatography and showed the maximum hemagglutination activity at a temperature range of 10 °C to 40 °C and at pH 7.0 to 9.0. Denaturants like urea and acidic-guanidine inhibited its hemagglutination activity significantly. MytiLec-1 was found to be metal-independent though Ca2+ slightly increased the activity of chelated MytiLec-1. The lectin suppressed 65 % growth of Pseudomonas aeruginosa (ATCC 47085) at 200 µg/ml and reduced the formation of biofilm (15 % at 200 µg/ml). Comparing to Shigella sonnei (ATCC 29930), Shigella boydii (ATCC 231903) and Shigella dysenteriae (ATCC 238135), Bacillus cereus (ATCC 14579) was slightly more sensitive to MytiLec-1. At a concentration of 200 µg/disc and 100 µg/ml, MytiLec-1 prevented the growth of Aspergillus niger and agglutinated the spores of Aspergillus niger and Trichoderma reesei, respectively. Amino acid sequences, physicochemical properties and antimicrobial activities of MytiLec-1 were compared with three other lectins (CGL, MTL and MCL from Crenomytilus grayanus, Mytilus trossulas and Mytilus californianus, respectively) from the mytilectin family of bivalve mollusks. It reconfirms the function of these lectins to recognize pathogens and perform important roles in innate immune response of mussels.

Rare earth elements in different body parts of the mussel Mytilus galloprovincialis (Crimea, Black Sea) and assessment of associated human health risks from its consumption.

The rare earth element (REE) pollution in the hydrosphere has become a matter of serious concern lately. In this study, using inductively coupled plasma mass spectrometry, the REE contents in soft tissue, byssus and shell liquor of the mussel Mytilus galloprovincialis, as a potential REE pollution bioindicator, in the Black Sea were determined for the first time. The highest REE levels were observed in mussels from the seabed. The REE contents in byssus and shell liquor were higher than in soft tissue. In byssus, the contents of Y, La, Ce, Nd and Dy were the highest, whereas in shell liquor, the heavier REE and Sc were the most concentrated. No likely REE-associated risks from the mussel meat consumption were detected. In soft tissue and byssus, REE contents significantly correlated with that of silicon.

One-year variation in quantity and properties of microplastics in mussels (Mytilus galloprovincialis) and cockles (Cerastoderma edule) from Aveiro lagoon.

As filter feeders, marine bivalves inhabiting estuarine and coastal areas are directly exposed to microplastics (MPs) in water. To assess whether MPs number, and their shape, size, colour, and polymer type present in mussels (Mytilus galloprovincialis) and cockles (Cerastoderma edule) varied over one year, bivalves were collected over the year of 2019 in the lower part of the coastal Aveiro lagoon, Portugal. After extraction from the bivalve's whole-body soft tissues, a subset of the visually inspected particles was randomly separated for identification using the Fourier-transform mid-infrared (FT-MIR) spectroscopy. A fraction of the inspected particles, 26-32% of particles >100 µm, and 59-100% of smaller ones were confirmed as MPs. Concentrations varied within the intervals of 0.77-4.3 items g-1 in mussels and 0.83-5.1 items g-1 in cockles, with the lowest values observed in January. In winter, the accumulation of large-sized fibers was composed of a mixture of plastic types, which contrasted against the most abundant MPs in summer consisting mainly of polyethylene of diverse size classes and shapes. Temperature decrease registered in winter might have triggered a lower filtration rate, resulting in lower MPs concentrations in the whole-soft body tissues of organisms. Different properties of MPs found in bivalves between January-February and August-September appear to reflect changes in the characteristics of MPs available in the Aveiro lagoon.

Extraction method for the multiresidue analysis of legacy and emerging pollutants in marine mussels from the Adriatic Sea.

The release of hazardous chemicals into aquatic environments has long been a known problem, but its full impact has only recently been realized. This study presents a validated liquid chromatography-mass spectrometry (HPLC-MS/MS) method for detecting pharmaceutical and pesticide residues in mussels (Mytilus galloprovincialis). An innovative MS-compatible extraction method was developed and validated, demonstrating successful recovery rates for analytes at three different concentration levels (25-95%). The method detected the target analytes at ng/g concentrations with high accuracy (-7% to 11%) and low relative standard deviation (<10%) for both intra-day and inter-day analyses. After validation, the method was applied to mussel samples collected from a commercial farm near Senigallia, Adriatic Sea, detecting different contaminants in the range of 2-40 ng/g (dry weight). The study provides a valuable tool for investigating the potential threats posed by diverse contaminant classes with high annual tonnage, including analytes with known persistence and/or illegal status.

The French Mussel Watch: More than two decades of chemical contamination survey in Mediterranean coastal waters.

Active biomonitoring of chemical contamination (e.g., Cd, Hg, Pb, DDT, PCB, PAH) in French Mediterranean coastal waters has been performed for more than two decades. This study aimed at presenting the current contamination in 2021 and the temporal evolution of concentrations from 2000. Based on a relative spatial comparison, low concentrations were measured in 2021 at most sites (>83 %). Also, several stations with moderate to high levels were highlighted in the vicinity of major urban industrial centers (e.g., Marseille, Toulon) and near river mouths (e.g., Rhône, Var). Over the last 20 years, no major trend was revealed, mostly, especially for the relative high-level sites. This likely constant contamination over time, plus slight increases of metallic elements at a few sites, still raise questions on the efforts that remain to be made. The decreasing trends of organic compounds, in particular PAH, provide evidence of the efficiency of some management actions.

The mussel Mytilus galloprovincialis (Crimea, Black Sea) as a source of essential trace elements in human nutrition.

Micronutrients, or essential trace elements, are important components in various metabolic processes inherent to the normal functioning of organism. To date, a substantial part of the world population suffers from a lack of micronutrients in the diet. Mussels are an important and cheap source of nutrients, which can be utilized to mitigate the micronutrient deficiency in the world. In the present work, using inductively coupled plasma mass spectrometry, the contents of the micronutrients Cr, Fe, Cu, Zn, Se, I, and Mo were studied for the first time in soft tissues, shell liquor, and byssus of females and males of the mussel Mytilus galloprovincialis as the promising sources of essential elements in the human diet. Fe, Zn, and I were the most abundant micronutrients in the three body parts. Significant sex-related differences in the body parts were detected only for Fe, which was more abundant in byssus of males, and Zn, which exhibited higher levels in shell liquor of females. Significant tissue-related differences were registered in the contents of all the elements under study. M. galloprovincialis meat was characterized as the optimal source of I and Se for covering the daily human needs. Regardless of sex, byssus turned out to be richer in Fe, I, Cu, Cr, and Mo in comparison with soft tissues, which fact allows recommending this body part for the preparation of dietary supplements to compensate for the deficiency of these micronutrients in the human body.

Microplastics in mussels from the Boka Kotorska Bay (Adriatic Sea) and impact on human health.

This study evaluated the microplastic abundance, shape, color, size and chemical composition of microplastic in mussels and estimated human exposure to microplastic through consumption of mussels collected from Boka Kotorska Bay (Adriatic coast of Montenegro). Microplastic was found in 53.3% of the studied mussels, with an average microplastic abundance of 2.53 ± 1.1 items/individual. Most of the ingested microplastic were fibers (63.7%), which were blue in color. FT-IR revealed that 98% of the examined particles were plastic, with seven polymers identified, of which polyethylene, polypropylene, and polyethylene terephthalate were the most abumdant polymers in mussels. Three of the polymers detected in mussels (polyamide, polyvinyl chloride and polystyrene) are classified as hazardous by the European Chemical Agency with warning or danger signals. With one serving of mussels, consumers would ingest 22.7 microplastic particles, while the annual dietary intake of microplastic via consumption of mussels was estimated at 99 MP/year.

Analysis of imidazolium ionic liquids in biological matrices: A novel procedure for the determination of trace amounts in marine mussels.

Imidazolium ionic liquids (ILs) are chemical compounds beginning to be used on a mass scale. Although their presence in the environment is usually treated as only potential threat, there are already first evidences that this has become a real case. Taking into account their increasing use it might be expected that this problem will also increase in the nearest future. Given that some of the imidazolium cations exhibit high potential for bioconcentration, it is likely that they will accumulate in the tissues of wild organisms. Thus, there is no doubt that monitoring the presence of these compounds in organisms from potentially contaminated waters will be needed. Therefore, the aim of our study was to develop and fully validate a novel and reliable analytical procedure for the determination of the mixture of imidazolium ILs in Mytilus trossulus mussels. For this purpose, different extraction techniques were tested such as: microwave-assisted extraction (MAE), accelerated-solvent extraction (ASE) and bullet-blender homogenization (HOMO). Finally, the proposed procedure is based on the application of MAE technique for the extraction of imidazolium cations and SPE technique using Oasis HLB cartridges for the purification of the obtained extracts and LC-MS/MS technique with QqQ analyzer for their final determination. Absolute recoveries of the proposed analytical procedure reached 71-90%. The developed procedure is characterized with low limits of quantification, at 50-100 ng g-1 dry tissue and allows for reliable determination of trace amounts of the tested compounds in complex biological matrix. Matrix effects obtained for the optimized procedure ranged from 7.8 to 37.5%. As a result, this is the first study presenting the analytical procedure for the analysis of imidazolium ILs in aquatic animal tissues.

Polycyclic aromatic compound and trace metal element residues in Mytilus mussels at marine wildlife hotspots on the Pacific coast of Canada.

The Pacific coast of Canada has a rich marine fauna and a growing human population with increasing potential for pollution releases, but there is currently little overlap between marine wildlife hotspots and ongoing biomonitoring efforts for less bioaccumulative contaminants such as polycyclic aromatic compounds (PAC) and trace metals (metals). We surveyed PACs and metals at marine bird breeding colonies in coastal British Columbia in 2018 by analyzing chemical residues in the soft tissue of bivalve Mytilus sp. mussels collected from stations (n = 3) at seven sites. The concentration of sum PACs (∑43PAC) and high molecular weight (HMW) PACs were highest at the Second Narrows colony in Vancouver Harbour, a highly urbanized and industrialized port within the Salish Sea. For conservation areas, two Salish Sea and three Pacific Ocean coast colonies, PACs were generally lower. However, ∑43PAC, ∑HMWPAC, and several HMW congeners at the remote site of Triangle Island, a Marine National Wildlife Area, were not significantly different from Second Narrows. The dominant PAC sources at all sites are likely pyrogenic rather than petrogenic, as suggested by PAC profiles, proportion of parent PACs, and source-indicator congeners. For metals, site differences were found for seven out of eight priority metals, but principal component analysis indicated that site differences, such as high mercury and cadmium at offshore sites, are likely related to environmental and biological variables including salinity, condition index, water temperature, and shell length. Our survey across a broad coastal region shows that PAC and metal biomonitoring programs with mussels should include wildlife hotspots where the exposure of protected vertebrate species to pollutants with low bioaccumulation potential would be less obvious, and shows that collection of data on key covariates (e.g. lipid content, salinity) will be critical to tracking long-term trends and detecting pollution release events.

Elements in Mediterranean mussels from Istanbul and exposure assessment.

In this study, concentrations of elements were determined in edible tissues of Mytilus galloprovincialis by means of inductively coupled plasma mass spectrometry (ICP-MS). The mean levels (mg kg-1) of 0.67 for Cd, 6.9 for As, 0.79 for Pb, 2 for Ni, and 42.6 for Zn exceeded the maximum limits in the digestive glands. Also, the mean concentrations of Cd and As in muscle and of Cd and Ni in gills were above the maximum limits. The highest value was found for As in a digestive gland, with 65.4% of the Provisional Tolerable Weekly Intake. In addition, the lowest percentage belonged to Zn with 0.2% of PTWI in muscles and 0.3% of PTWI in gills of the mussels. Mercury concentrations were well below legal limits.

Chemical composition and morphology of the Mediterranean mussel, Black Sea coast of Russia.

Mussels, whose soft tissues are used in food and are rich in high-quality protein, are essential in marine fisheries. Mediterranean mussels (Mytilus galloprovincialis Lam) used to assesses the pollution level of a coastal marine zone due to exposure to local technological processes populate the metal piles of a pier built for the 2014 Olympics in Sochi Olympic Park. The chemical composition of mussel soft tissues (61 elements analyzed by the ICP method) indicates anthropogenic pollution of the coastal zone ecosystem, most pronounced in the 50-m zone along the coast due to run off from the terrestrial ecosystem affected by the Olympic construction. Line measurements of annual rings of 6-year-old individuals of mussels showed stabilization of the ecological situation in the coastal-marine zone by 2019. This study can be used for comprehensive ecological monitoring of coastal-marine zones with similar conditions and anthropogenic load.

Microplastics in seafood: Relative input of Mytilus galloprovincialis and table salt in mussel dishes.

Due to current marine pollution, microplastics ingestion through seafood is an increasing risk for consumers. In this study, microplastics from mussels (Mytilus galloprovincialis) and table salt employed in popular dishes in Bay of Biscay (Spain) were quantified and analysed by Fourier-Transformed Infrared spectroscopy. Microplastics varied in mussels (mean 0.55-3.20 items/g) depending on the environmental pollution of the collection point (seawater, 0.002-0.015 items/mL; sand, 0.06-0.38 items/g). Microplastics content in table salt (0.1-0.38 items/gr) was much lower than in mussels. Chemical substances found from microplastics in mussels and salt are catalogued as hazardous for human health. Significant correlation between microplastics in sand and mussels was found, suggesting that consumers' risk of microplastics ingestion depends on the harvesting area. Routine microplastics analysis in mussels and disclosure of microplastics content on seafood labels are recommended for conscious, informed consumption.