Microplastics (MPs) widely distribute in marine environments and generate severe hazards to marine biota, yet little is known regarding the toxic impacts of aged MPs on benthic invertebrates and their surrounding sediment microbiota. This work aimed to fill this research gap by exploring the comprehensive toxicity of aged polymethylmethacrylate microplastics (PMMA-MPs) toward Urechis unicinctus and its sediment habitat. A 21-day laboratory exposure trial was performed with two PMMA-MP treatments: environmentally realistic low concentration (10 μg/L) and extreme high concentration (1000 μg/L). Aged PMMA-MPs accumulated in the body wall and intestine of U. unicinctus, with markedly higher body wall MPs loads in the high-dose group (p < 0.05). High-concentration PMMA-MPs significantly raised intestinal total protein and triggered intense oxidative stress (p < 0.01), and the Integrated Biomarker Response value rose dose-dependently. Sediment microbial β-diversity was obviously reshaped (p < 0.05), with enriched pathogens including Klebsiella and Enterobacteriaceae under high MP exposure, while the worm’s intestinal α-diversity and core microbiome remained stable, showing host adaptability. This study reveals multi-level toxic outcomes of aged PMMA-MPs on benthic worms and their sediment microhabitat, offering fundamental data to evaluate the ecological risks of weathered MPs in marine benthic systems.

Fluorene is biotransformed into the more toxic 2-hydroxyfluorene in the Perinereis aibuhitensis. However, the underlying toxicological mechanisms remain poorly defined. This study aims to decipher the mechanisms of intestinal injury in P. aibuhitensis under 2-hydroxyfluorene exposure. This study employed an integrated multi-endpoint approach to evaluate the dose-dependent effects of 2-hydroxyfluorene (0, 5, 50, and 500 μg/L) on P. aibuhitensis over a 28-day period. Results demonstrated that escalating concentrations triggered pronounced metabolic stress, indicating a shift in energy allocation toward detoxification and repair. Histopathological analysis identified the intestine as the primary target, showing mucosal necrosis and fragmented muscle fibers. These structural aberrations were mechanistically linked to sustained oxidative stress, which compromised intestinal permeability and paralyzed digestive and neurological functions. 16S rRNA sequencing further revealed that 2-hydroxyfluorene exposure reduced gut microbial diversity and the abundance of the beneficial genus, while promoting the abundance of the harmful genus. In conclusion, 2-hydroxyfluoreneinduces severe intestinal injury and metabolic dysfunction in P. aibuhitensis by initiating a vicious cycle: direct oxidative damage compromises gut barrier integrity, which in turn fosters dysbiosis microbiota. This dysbiosis characterized then likely exacerbates the initial host injury. This host-microbe interplay likely exacerbated the initial intestinal injury. These findings highlight the significant ecological risks posed by hydroxylated polycyclic aromatic hydrocarbon (PAH) metabolites to marine benthic invertebrates and underscore the crucial contribution of the gut microbiome in mediating environmental toxicity.

Astaxanthin (AST), a marine xanthophyll with antioxidant, anti-inflammatory and immunomodulatory activity, is constrained by hydrophobicity, photo-oxidative instability and a vehicle- and prandial-state-dependent oral bioavailability of ≈10–50%. We critically appraise nanodelivery systems (NDSs) for AST — primarily oral liposomes, nanoemulsions, solid lipid nanoparticles, nanostructured lipid carriers, polymeric nanoparticles, Pickering emulsions and layer-by-layer microcapsules, with emerging exosome and electrospun-nanofibre platforms and selected parenteral examples — that improve solubility, gastrointestinal stability, intestinal targeting and controlled release. Where head-to-head data exist, nano-AST achieves 2- to 10-fold gains in peak plasma concentration (Cmax) and area under the curve (AUC) over oil-based references. Nano-AST reshapes the gut microbiome–host metabolic axis through short-chain fatty acids, bile acids and tryptophan-derived aryl hydrocarbon receptor (AhR) ligands, attenuating inflammaging, improving glucolipid homeostasis and supporting neuroprotection. We summarize regulatory positioning, the global market and representative human studies, and identify multi-omics integration, scalable manufacture and head-to-head clinical trials as translational priorities.

The application of Perinereis aibuhitensis is limited by the poor flavor of its hydrolysate. Thus, we aimed to optimize the preparation conditions of P. aibuhitensis Maillard reaction solution (PMS) by using a response surface methodology (RSM) combined with a back-propagation neural network coupled with a genetic algorithm (BP-GA). The optimal conditions were as follows: ribose:glucose, 1:1; reducing sugar addition, 3.21%; pH, 6.5; reaction temperature, 121 °C; and reaction time, 64 min. The volatile flavor components and free amino acid content in PMS (prepared under the optimal conditions) and P. aibuhitensis enzymatic hydrolysis solution were determined. PMS had good flavor, reduced aromatic hydrocarbon and ether contents, and increased aldehyde. The proportions of bitter and sweet amino acids decreased and increased, respectively, which significantly improved taste. This study demonstrates the effectiveness of machine learning-assisted optimization for flavor enhancement and provides a viable strategy for developing high-value seafood seasonings from underutilized marine resources.

AbstractWaterless transport is an alternative method for live aquatic products. However, the changes that occur in the fish body after transportation are not known. Herein, the effects of different transport methods on quality of turbot (Scophthalmus maximus) were investigated. Fish were divided into four groups: Group A (water, 17°C), Group B (waterless, 3°C), Group C (water, 3°C), and Group D (control, 17°C). In the case of 100% survival, the maximum transport time was 40 h for Group A, 55 h for Group B, and 90 h for Group C. Both crude protein and crude fat decreased significantly (p < 0.05) in the treatment groups compared with the control group. Compared with control group, lactic dehydrogenase (LDH), lactic acid (LA), and serum cortisol (COR) increased significantly (p < 0.05) in all treatment groups. After fish recovered, LDH, LA, and COR values were all significantly (p < 0.05) lower than their corresponding non‐recovered group. Compared with the control group, the expression of proteins related to muscle motility and stress capacity both decreased in the low‐temperature, waterless group. Together, obvious damage may occur to flesh quality, liver, and heart of turbot when the transport time is >40 h, regardless of the transport method.

The polychaeta Neanthes japonica is a common by-product in mariculture ponds. It is rich in essential nutrients, but has not been well-explored. Therefore, this 56-day experiment investigated the effects of substituting N. japonica meal for dietary fishmeal on juvenile tiger puffer (15.49 ± 0.02 g, n = 450 fish). The control diet (CON) contained 40% fishmeal. Freeze-dried N. japonica meal (FNM) was supplemented into CON at the levels of 3% (FNM3), 6% (FNM6), and 9% (FNM9), replacing fishmeal. The fifth diet contained 6% oven-dried N. japonica meal (ONM6), replacing fishmeal. The results indicated that no significant difference was observed in growth, feed efficiency, and somatic index among all the treatment groups. The feed intake of the FNM6 group was significantly higher compared to CON. No significant difference was detected in fish proximate composition, as well as the fatty acid composition, amino acid composition, and muscle texture. The supplementation of N. japonica meal decreased the activities of intestinal lipase and α-amylase. The addition of freeze-dried N. japonica meal significantly up-regulated the expression of the intestinal amino-glycine transporter pat1. It was concluded that adding 9% N. japonica meal to the feed had no significant effect on the growth performance and body composition of juvenile tiger puffer.

Heavy metals and nutrients were studied to identify geographical regions of Urechis unicinctus. Urechis unicinctus were selected from four different origins of China (Qingdao, Dalian, Yantai and Qinhuangdao). The content of heavy metals (Fe and Zn) and nutrients (crude ash, crude protein, crude fat and moisture) was determined, and the causes of regional differences were analyzed. Cluster analysis (CA) and fisher linear discriminant analysis (FLD) were applied to differentiate the U. unicinctus geographical origin. The CA was the effective method for U. unicinctus analysis of laver samples. By cross validation, FLD correctly classified 100.00% of U. unicinctus samples from four regions, respectively. Therefore, it is possible to identify geographical regions of U. unicinctus based on the content of heavy metals and nutrients and multiple statistical analysis.

Raw aquatic food is regarded as an important source of proteins. However, the presence of various bacteria can increase the risk of disease in humans. As a result, a crucial step in the processing of aquatic products is the disinfection of raw aquatic food. An intelligent ultraviolet c radiation (UVC) sterilization system was established and evaluated in this study. On the automated production line, the UVC lamp's sterilization intensity can be automatically adjusted to achieve intelligent sterilization of the various aquatic product categories. The system was implemented and evaluated for oyster surface sterilization experiments in the production line. The quality indicators of oysters, such as volatile salt nitrogen content and aerobic bacterial count, were measured before and after sterilization. The average sterilization rate of the intelligent system is 96.4%. The results showed that the system had an excellent sterilization effect and improved the shelf life of aquatic products.

Aquatic foods such as fish, shrimp, and shellfish are important human nutrient sources. However, aquatic foods spoil quickly during processing and storage due to spoilage bacteria and endogenous enzymes. Ultra-high-pressure (UHP) technology, as an advanced non-thermal treatment method, is an effective preservation technique for aquatic foods. The mechanism of UHP technology is to destroy non-covalent bonds by UHP, which leads to the change of cell membrane permeability and the destruction of high-level structure of proteins, making apoptosis and enzyme inactivation. The technology can effectively sterilise and preserve food's colour, taste and nutritional value. The paper provides an introduction to the working principles, types, sources and equipment and describes the progress of the research and application of UHP technology in pascalisation, enzyme inactivation, parasite inactivation and quality modification of aquatic products. Potential limitations and prospects of the technology are also outlined. We hope to lay the theoretical groundwork for using this technique in aquatic product processing and provide guidance for its application in industrial production.

The Urechis unicinctus is a rare treasure benthonic animal that most seen in China, Japan and Korean Peninsula. As the research moves along, people gradually realized that Urechis unicinctus possesses delicious meat with high economic value. High protein content and the presence of numerous essential amino acids in the body wall muscle are arguments for regular consumption to increase human health. This paper reviews and discusses available research results regarding biology, ecology and physiology of Urechis unicinctus emphasizing its potential to be valorized for different industries. Nevertheless, the paper provides references for further studies dealing with producing of Urechis unicinctus under controlled conditions.

Perinereis aibuhitensis (Grube, 1878) lives in marine sediments of estuary or shoal areas, where substrate has some crucial environmental factors affecting its burrowing and distribution. In order to provide basic data for the habitat selection and suitability evaluations of the artificial aquaculture of P. aibuhitensis, this paper conducted a quantified analysis of its burrowing ability and explored its behavioral preferences in different substrates, including mud (<75 μm), fine sand (125-250 μm), medium sand (250-500 μm), coarse sand (500-2 000 μm), gravel (2 000-4 000 μm) and ceramsite (4 000-8 000 μm). The research results revealed that substrate grain size significantly affected the burrowing time, burrowing rate, burrowing depth and distribution rate (P<0.01). Moreover, P. aibuhitensis demonstrated preferential selections relating to substrate grain sizes, had higher burrowing ability in ceramsite, mud and fine sand compared with other substrates. The strongest burrowing ability and the highest distribution rate were observed in ceramsite. The study indicated that P. aibuhitensis was sensitive to substrate grain size, which also had an impact on its burrowing process and population distribution. In the natural sea, substrates mainly composed of mud and fine sand are fit for aquaculture and stock enhancement. Based on behavioral preferences and ecological rehabilitation function of P. aibuhitensis, this paper proposes a symbiotic system of marine animals and halophytes, and constructs an ecosystem model of “Marine fish-Halophytes-Perinereis aibuhitensis” with P. aibuhitensis as the link.

In order to find out the optimal substrate grain size and mud-sand ratio and improve the burrowing ability of Urechis unicinctus juveniles, we explored the effects of substrate grain size (fine sand: 125-250 mu m; medium sand: 250-500 mu m; coarse sand: 500-2000 mu m) and mud-sand ratio (0:1; 3:7; 1:1; 7:3; 1:0) on the burrowing ability of juveniles with a body length of 1.50 +/- 0.14 cm and a weight of 0.50 +/- 0.06 g. Results showed that substrate grain size and mud-sand ratio significantly affected minimum burrowing time, burrowing time and burrowing rate respectively (P<0.01). In the fine sand, juveniles had the shortest mean minimum burrowing time and mean burrowing time, and the highest mean burrowing rate, as opposed to those of coarse sand. With the rise of mud content in substrate, the mean minimum burrowing time and mean burrowing time increased markedly (P < 0.01), while the mean burrowing rate decreased significantly (P<0.01). The interaction of substrate grain size and mud-sand ratio had a significant effect on minimum burrowing time and burrowing time (P<0.01), but showed no effect on burrowing rate (P>0.05). Thus, it can be concluded that smaller the substrate grain size and the lower the mud content, the shorter minimum burrowing time and burrowing time, the higher the burrowing rate and the burrowing ability. In the culture of U. unicinctus, farmers need to choose small grain size substrate with high sand content, and avoid large grain size substrate with high mud content. (C) 2019 Friends Science Publishers

In this study, the content and bioaccessibility of rare earth elements (REEs) in Porphyra spp. Samples before and after thermal treatments were investigated. Additionally, the risks of REEs exposure to human health were assessed. REEs content significantly reduced after thermal processing (P < 0.01), and the removal rate of REEs was approximately 30%. Thermal treatment increased REEs bioaccessibility from 44% to 64.34%. The concentration and bioaccessibility of Ce, La, Y, Nd were high in raw and thermally treated Porphyra samples, and there was no correlation between REEs content and bioaccessibility. Based on the following parameters: highest content of REEs in the studied seaweed samples (13.45 mg/kg), the highest daily seafood consumption (44.9 g/day), and the highest bioaccessibility (64.34%), the ratio of the calculated daily intake (DI) to daily allowable intake by diet (DAI(diet)) of REEs did not exceed the reference value in rare earth mining areas or under extreme conditions. The DI via seafood consumption would be exceeded when the content of REEs in the seafood sample is greater than 15.77 mg/kg. In this study, the concentration of REEs did not exceed 15.77 mg/kg in any sample. Thus, the human health risks of REEs associated with seafood are low.

Cadmium is a known metal contaminant in the Bohai Sea. In this study, the dose-dependent responses induced by Cd were characterized in marine polychaete Perinereis aibuhitensis using the endpoints, including activities of enzymes, expression levels of stress-responsive genes and metabolic responses. Both enzyme activities and gene expression levels exhibited the hormetic effects induced by Cd in P. aibuhitensis, as shown by the typical U-shaped or inverted U-shaped response profiles. The highest concentration (1280 µg/L) of Cd exposure induced obvious oxidative stresses. NMR-based metabolomics revealed that Cd induced both linear dose-dependent effects (69.13% of the total variation) and a relatively slight hormesis (5.54% of the total variation) in energy metabolism in P. aibuhitensis at metabolite level. In details, Cd exposures linearly reduced the consumption of amino acids and enhanced the consumption of glucose for energy supply, resulting in elevated contents of amino acids and depleted contents of glucose. Additionally, Cd treatments induced hormesis in the conversion of ATP hydrolysis to AMP. This work suggested that the hormetic effects should be considered in the ecological risk assessment for the environmental pollutants.

This paper puts forward the reasonable choice of live transportation strategy to guarantee survival rate and quality of Urechis unicinctus by designing its packaging mode and carrying out real-time monitoring technologies. Ambient data sensing devices are designed and deployed in water and waterless transportation facilities by which the simulation of real live transportation is tested. During the delivery process of live Urechis unicinctus, the key ambient factors temperature, dissolved oxygen/oxygen, carbon dioxide, PH, salinity-are dynamically sampling by on-line electronic monitoring equipment. Urechis unicinctus transport ambient data and their correlations are statistically calculated and analyzed by transportation monitoring and analysis system for the two transportation strategies. Through five control groups test for water and waterless shipment, it is found that waterless transportation is more suitable for over 30 h live transportation by studying transportation facilities management, surface characteristics and survival rate, which can provide a sound statistical basis of reasonable transportation mode to guarantee consumers to eat healthier and cheaper seafood with more convenient and economical way.

Heat shock 70 kDa protein 12A (HSPA12A) is an atypical member of HSP70 family, and the translationally controlled tumor protein (TCTP) is a novel HSP with chaperone-like activity. They are both involved in protecting organisms against various stressors. In the present study, the cDNAs of HSPA12A and TCTP (called MgHSPA12A and MgTCTP) were identified from Mytilus galloprovincialis by RACE approaches. The full-length cDNA of MgHSPA12A and MgTCTP encoded a peptide of 491 and 171 amino acids, respectively. Real-time PCR was employed to analyze the tissue distribution and temporal expression of these two genes after bacterial challenge and cadmium (Cd) exposure. It was found that the transcripts of MgHSPA12A and MgTCTP were dominantly expressed in gonad and muscle, respectively. The expression level of MgTCTP at 48 h post Vibrio anguillarum challenge was detected to be significantly up-regulated in hepatopancreas (P < 0.05). As concerned to Cd exposure, 2.0-fold increase of MgHSPA12A expression compared to that of the control was observed at 48 h in 5 μg/L Cd2+-treated group, while the expression levels of MgTCTP were significantly decreased after exposed to both 5 and 50 μg/L Cd2+ for 24 h and 96 h. These results suggested the potential involvement of MgHSPA12A and MgTCTP in the mediation of the immune responses and environmental stress in mussels.

The full-length cDNA sequences coding respectively for a manganese superoxide dismutase (Mg-MnSOD) and copper/zinc superoxide dismutase (Mg-CuZnSOD) were cloned from Mytilus galloprovincialis. Mg-MnSOD and Mg-CuZnSOD cDNAs encoded a polypeptide of 228 and 211 amino acids, respectively. Sequence analysis indicated Mg-MnSOD was a mitochondrial MnSOD and Mg-CuZnSOD was an intracellular CuZnSOD. Multiple alignment analysis showed that both Mg-MnSOD and Mg-CuZnSOD sequences had the common features conserved in MnSODs and CuZnSODs, respectively. Phylogenetic analysis revealed that Mg-MnSOD clustered together with MnSODs from other mollusks, whereas Mg-CuZnSOD clustered with other mollusk intracellular CuZnSODs with a wider phylogenetic distance. By quantitative real-time RT-PCR (qPCR) analysis, both Mg-MnSOD and Mg-CuZnSOD transcripts were detected in all tissues examined with the highest expression level in hepatopancreas. Following bacterial challenge, the expression level of Mg-MnSOD and Mg-CuZnSOD increased first and subsequently decreased to the original level in hemocytes. In hepatopancreas, Mg-CuZnSOD mRNA was up-regulated significantly at 72 h and 96 h post challenge, while the level of Mg-MnSOD transcript had no significant change. Therefore, Mg-MnSOD and Mg-CuZnSOD expressions were inducible and they were probably involved in the immune response against bacterial challenge. These results suggest that these SODs may play important roles in the immune defense system of M. galloprovincialis and perhaps contribute to the protective effects against oxidative stress in this mussel. (C) 2013 Elsevier Ltd. All rights reserved.

Glutathione peroxidase (GPx) is a key enzyme of cellular detoxification systems that defend cells against reactive oxygen species. It can be divided into selenium-dependent GPx (Se-GPx) and selenium-independent GPx (non-Se-GPx) subfamilies. In this study, the full-length cDNA of a non-Se-GPx was identified from Venerupis philippinarum (denoted as VpGPx) using EST analysis and RACE approaches. The full-length cDNA of VpGPx encoded a polypeptide of 226 amino acids with the predicted molecular mass of 25.41 similar to kDa. Phylogenetic analysis indicated that VpGPx had higher evolutional conservation to invertebrate than vertebrate counterparts and should be a new member of the GPx protein family. Spatial expression analysis found that VpGPx transcript was most abundantly expressed in hepatopancreas, gills and haemocytes, and weakly expressed in the tissues of mantle. After Vibrio anguillarum challenge, the expression of VpGPx transcript in overall haemocyte population was down-regulated in the first 6 similar to h, and increased to the peak at 48 similar to h. As time progressed, the expression level dropped to 0.5-fold of the control level at 96 similar to h. All these results indicated that VpGPx was perhaps involved in the immune response against microbe infection and might be contributed to the clearance of bacterial pathogens.

HSP40 was an understudied protein family with co-chaperone activity. In the present study, a HSP40 homology was cloned from Venerupis philippinarum haemocytes (designated as VpHSP40) by EST analysis and RACE approaches. The expression profiles of VpHSP40 under Vibrio anguillarum challenge and heavy metal exposure were investigated by quantitative real-time RT-PCR. The bacterial challenge could significantly up-regulate the mRNA expression, and the highest expression level was detected at 24 h post-infection with 6.0-fold increase compared with that in the control group. During heavy metal exposure experiment, the expression of VpHSP40 could also be induced by Cu(2+) and Cd(2+) at different concentration, where Cu(2+) displayed more toxic effect on clam than that of Cd(2+). Concerning the same heavy metal, varied effect on VpHSP40 expression was detected at different concentration of heavy metal. Taking together, these results suggested that VpHSP40 was perhaps involved in mediating the immune responses and environmental stresses in V. philippinarum.