Search Results (385)

The Mediterranean Sea urchin Paracentrotus lividus is a key benthic herbivore and a valuable fishery resource because of the high commercial and gastronomic value of its edible gonads. Increasing market demand, overharvesting, climate change, habitat degradation, and pollution have contributed to the decline of wild populations in several Mediterranean areas. This narrative review, including a preliminary case study, provides an integrated perspective on the role of P. lividus in conservation-oriented aquaculture, with particular attention to Integrated Multi-Trophic Aquaculture (IMTA), microbiological quality, sperm quality assessment, cryopreservation, and germplasm biobanking. IMTA may improve nutrient recycling and resource-use efficiency, whereas cryopreservation and biobanking can support genetic resource conservation, selective breeding, hatchery production, and future restocking programs. Within this framework, the ongoing AVATIM project (“Virtuous Aquaculture in Integrated Marine Multitrophic Aquaculture”) is presented as an operational case study illustrating how reproductive biotechnology may be integrated into sustainable multitrophic aquaculture and germplasm conservation strategies. Baseline sperm quality parameters of sexually mature males collected from the southern Adriatic Sea were assessed using Computer-Assisted Sperm Analysis and flow cytometry, providing baseline values for future cryopreservation studies and biobanking applications. Overall, AVATIM illustrates how IMTA, reproductive biotechnology, and genetic resource conservation may jointly support sustainable Mediterranean Sea urchin management. Full article

The morphology and micromorphology of Aristotle’s lantern, the feeding apparatus of Scaphechinus mirabilis, were examined using light microscopy, scanning electron microscopy, and X-ray microscopy. S. mirabilis had food grooves on the ventral side, which extended to the mouth. Aristotle’s lantern was a star-shaped calcareous skeletal structure attached to the test by the apophysis and consisted of pyramids, joints, and teeth. The pyramid consisted of two demi-pyramids, an epiphysis, and a bump, whereas the joint located between the pyramids consisted of the interpyramidal ligament and rotula. The tooth was an elongated trapezoid with one pointed end (3.98 × 0.97 × 0.38 mm) and was divided into an embedded part and a projection part. The embedded part was connected to the dental ligament and dental promoter muscle, whereas the projection part was divided into a basal projection part covered by the peridental membrane and an apical projection part protruding beyond the tooth slide. The tooth exhibited a calcareous lamellar structure composed of 15–20 layers, and its distal end was worn. These findings indicate that the morphology of the tooth is specialized for internal crushing of sediment and food particles within the Aristotle’s lantern. Full article

Bone loss represents a significant clinical burden that has driven the development of improved orthopedic graft substitutes. Although current grafting options, including autografts, allografts, and xenografts, have demonstrated considerable therapeutic potential, their widespread application is constrained by limitations such as donor scarcity, limited availability, and associated clinical risks. Consequently, biologically derived materials, including avian eggshells and marine bivalve shells, have emerged as promising alternative sources to produce bone precursor materials and next-generation bone graft substitutes. This review summarizes recent advances in avian eggshell- and marine shell-derived calcium carbonate (CaCO₃) materials for bone regeneration and examines their preclinical evaluation in diverse animal models, including critical-size defects in calvarial, femoral, radial and mandibular bone. Relevant studies published over the past ten years were systematically analyzed, focusing on natural calcium carbonate systems derived from avian eggshell and marine shells, including oyster, mussel, clam, scallop, cockle, and sea urchins. A structured literature search was conducted using PubMed, Scopus, and Google Scholar to identify studies published between 2015 and 2025 investigating eggshell- and aquatic-derived biomaterials for bone repair and regeneration. Eligible studies were screened, and data were comparatively analyzed with respect to biomaterial source, scaffold fabrication, physicochemical characteristics, mechanical performance, biocompatibility, osteogenic potential, and the use of preclinical animal studies. Eggshell-derived biomaterials currently show the strongest translational evidence, while aquatic shell-derived biomaterials remain promising but underexplored for bone regeneration. Furthermore, this review critically examines the scientific, manufacturing, and regulatory challenges that must be addressed before clinical implementation. Full article

To investigate sex-specific differences in gonad quality and flavor characteristics of the sea urchin Heliocidaris crassispina, female and male gonads were compared using proximate composition, colorimetry, E-tongue, E-nose, LC-MS, and HS-SPME-GC-MS. No significant sex differences were observed in wet weight, test diameter, gonadosomatic index, moisture, or crude fat, whereas female gonads showed higher crude protein content, lightness, and yellowness. E-tongue and E-nose analyses revealed distinct sex-dependent taste and odor fingerprints. Metabolomics identified 366 differential non-volatile metabolites and 53 differential volatile metabolites, mainly involving lipids, organic acids and derivatives, dipeptides, nucleotide-related compounds, hydrocarbons, terpenoids, aldehydes, ketones, and esters. Female gonads were enriched in phospholipids, lysophospholipids, dipeptides, and nucleotide precursors, whereas male gonads contained higher levels of acylcarnitines, hydroxy fatty acids, 3-carene, and hydrocarbons. These findings provide metabolomic evidence for sex-dependent flavor differences and support quality evaluation of sea urchin products. Full article

Background/Objectives: The long-spined sea urchin Diadema antillarum is a keystone herbivore whose grazing maintains Caribbean coral reefs; basin-wide mass mortalities in 1983–1984 and 2022 have made genomic resources a conservation priority, yet no nuclear genome existed for the species. We aimed to generate the first nuclear reference and to resolve the high heterozygosity that complicates genome assembly in broadcast-spawning marine invertebrates. Methods: For the assembly, we combined PacBio HiFi, Oxford Nanopore, and Illumina sequencing. Genome size and heterozygosity were estimated by k-mer profiling. We compared standard and haplotype-aware assembly strategies (hifiasm), evaluated completeness with BUSCO, and annotated repeats using a species-specific RepeatModeler library. Results: k-mer profiling estimated a haploid genome of ~703 Mb with 2.52% heterozygosity. Standard assembly then produced an inflated 1.75 Gb assembly (98.4% BUSCO-complete but 84.4% duplicated), indicating retention of both haplotypes. Haplotype-aware reassembly separated this into a collapsed primary assembly (1.03 Gb) and two phased haplotypes (0.95 and 0.89 Gb), each comparable in size to the chromosome-level congener D. antillarum (886 Mb). BUSCO completeness reached 99.0%, with single-copy orthologs rising to 85–90%, and reference-free consensus quality reached QV 44.5 (Merqury; initial assembly). This genome is repeat-rich (42.84% repetitive; 29.96% unclassified). Conclusions: We provide the collapsed primary assembly together with both phased haplotypes as a haplotype-resolved reference for D. antillarum, establishing a foundation for immunogenomic, comparative, and population-genetic studies and for monitoring and restoration of this ecologically critical species. More broadly, the study shows that haplotype-aware assembly is essential for resolving such highly heterozygous genomes and delivers the genomic foundation needed to guide the conservation of this keystone Caribbean reef species. Full article

In recent years, a novel class of highly stable multiprotein complexes, with molecular masses ranging from 1 to 2 MDa, has been identified in human milk, placenta, sea urchin eggs, and sea cucumbers. These complexes exhibit extraordinary stability, dissociating only under stringent conditions involving 8 M urea, 3 M MgCl₂, EDTA, and DTT. Previous investigations have demonstrated that complexes derived from different organs of the sea cucumber Paracaudina chilensis differ in size, molecular mass, and protein/peptide composition; however, their enzymatic activities have remained unexplored. In the present work, we performed the first systematic analysis of phosphatase activity associated with highly stable complexes isolated from five organs of P. chilensis: the body wall, gonads, respiratory trees, intestine, and coelomic fluid. Complexes were purified via gel filtration chromatography on Sepharose 4B, followed by ultracentrifugation. Phosphatase activity was determined spectrophotometrically by monitoring the hydrolysis of p-nitrophenyl phosphate. Our results indicate that all five complexes harbor phosphatases with optimal pH values spanning 7.0 to 10.0. Alkaline phosphatases (pH 9.0–10.0) displayed pronounced organ specificity: maximal activity was observed in the intestinal complex, whereas minimal activity was detected in the gonadal complex. Phosphatase activity in complexes from the body wall and respiratory trees exhibited a bell-shaped dependence on Mg²⁺ concentration, with optima at 5 mM and 1 mM, respectively; in contrast, activity in the intestinal and coelomic fluid complexes increased to a plateau at 5–10 mM Mg²⁺. Ca²⁺ ions predominantly inhibited activity, with the notable exception of the intestinal complex, where they exerted no effect on hydrolysis. EDTA treatment resulted in complete inactivation of the enzymes in most complexes; however, intestinal activity was retained at 50% even at high chelator concentrations, suggesting the presence of a metal-independent phosphatase. Collectively, these data indicate that the stable multiprotein complexes of P. chilensis contain an organ-specific repertoire of phosphatases that differ in pH optimum, metal ion dependence, and inhibitor sensitivity. These findings open new avenues for understanding the roles of such complexes in organ-specific physiological functions and regenerative mechanisms in echinoderms. Full article

Sea urchins harbor diverse microbial communities that may contribute to host-associated ecological interactions, microbial competition, and chemical defense. However, the compartment-specific organization of sea urchin-associated microbiota and their predicted chemical-defense-related functional potential remain poorly understood under aquaculture conditions. In this study, 16S rRNA gene amplicon sequencing was used to characterize microbial communities in rearing water, coelomic fluid, intestine, stomach contents, and surface mucus of Hemicentrotus pulcherrimus (H. pulcherrimus). KEGG Orthology (KO)-based functional prediction was further performed to evaluate predicted chemical-defense-related functional potential, including predicted chemical-defense-related pathways, siderophore-related functions, quorum sensing-related functions, and bacterial competition- and secretion system-related functions. Rarefaction curves and Coverage values indicated sufficient sequencing depth. Alpha diversity and Nonmetric multidimensional scaling (NMDS) analyses revealed clear microbial differentiation among the five sample types, with rearing water showing higher microbial richness. Taxonomic analysis identified Pseudomonadota, Bacteroidota, Campylobacterota, Bacillota, Planctomycetota, and Spirochaetota as dominant phyla, with several discriminative taxa across compartments. KO prediction showed that total predicted abundance of predicted chemical-defense-related KOs differed significantly among sample types. Among host-associated compartments, surface mucus showed relatively higher predicted siderophore-related KO potential, whereas stomach contents showed higher predicted quorum sensing-related KO potential among host-associated compartments. These findings suggest compartment-specific microbial communities and predicted chemical-defense-related functional potential in cultured H. pulcherrimus under aquaculture conditions. Because these functions were inferred from 16S-based KO prediction, they should be interpreted as preliminary hypotheses for future metagenomic, metabolomic, and culture-dependent validation. Full article

Reef-building corals and coralline algae form the calcium carbonate frameworks that underpin tropical coral reefs, yet in some locations, coral cover has declined by ~50% in recent decades due to marine heatwaves and other stressors. Identifying refugia environments, such as upwelling systems, that may buffer stress, promote recovery, and could enhance resilience by promoting physiological plasticity that supports thermotolerance is therefore critical. Here, we compared benthic community composition, coral percent cover, and photophysiology between an upwelling location in the Gulf of Papagayo and a non-upwelling location in Sámara on the Pacific coast of Costa Rica. Waters in Papagayo were cooler, more acidic, and had higher chlorophyll-a concentrations. Reefs at this location exhibited higher crustose coralline algae, higher sea urchin abundance, and lower macroalgae cover, compared to Sámara. Papagayo also showed higher stony coral cover, driven by Pocillopora spp., while Sámara was dominated by massive, heat-tolerant Porites spp. Photophysiological parameters were significantly different between locations. Specifically, photosynthetic efficiency (F_v′/F_m′) was 10–45% higher, and maximum photosynthetic rate (P_max) was 20–40% lower in corals from Papagayo than in those from Sámara. These results reveal that two locations differing in environmental regime within a relatively small geographic area also differ in coral community composition and photophysiological features. Although further research is needed to resolve whether these environmental contrasts shape the observed biological differences, the observed patterns are consistent with the hypothesis that such regimes may support reef persistence or refugia, providing a basis for future work to test this hypothesis directly. Full article

This study presents the innovative design and development of biomimetic origami-based soft robotic grippers capable of two-stage grasping. Inspired by the biological structure of the sea urchin mouth, which combines external rigid teeth with an internal soft membrane, the proposed grippers employ origami architectures to achieve coordinated two-stage grasping. Novel waterbomb and Miura-ori origami architectures were introduced, enabling the formation of external and internal teeth. The developed grippers integrate an elastomeric membrane with an internal origami structure that enables contraction-driven folding under negative-pressure actuation. Multiple gripper configurations with varying dimensions are fabricated using paper and polymer-laminated paper skeletons. An energy-based modeling framework is introduced to describe the pressure–force relationship while accounting for the effects of structural deformation. Experimental evaluations conducted at different negative-pressure values quantified grasping performance and holding force. Imprint-based analysis confirmed the two-stage grasping mechanism, while grasping capability investigations demonstrated compliant interaction with delicate objects. Holding forces were measured using cylindrical metal and spherical wooden test objects of varying sizes and orientations. The waterbomb-based gripper achieved the most consistent performance, particularly for cylindrical objects, reaching a maximum holding force of 70 N, whereas the Miura-ori provided improved adaptability and higher holding forces for spherical objects, reaching 74.8 N, and maximum force-to-weight ratios of 327.2 and 346.6 were achieved for the waterbomb- and Miura-ori-based grippers, respectively. Full article

The sea urchin embryo represents a well-established model organism widely applied in embryo toxicity assays, ecotoxicological investigations, and biomonitoring studies. These analyses are primarily based on the morphological evaluation of embryos, which is conventionally carried out by experts through light microscopy. However, this approach is both time-intensive and inherently subjective, as the outcomes strongly depend on the evaluator’s expertise and experience. With the increasing adoption of machine learning techniques in image classification tasks, this study investigates the applicability of machine-learning-based approaches for the classification of sea urchin embryo images. The dataset used in this work originates from a previous study examining the effects of nickel exposure on Paracentrotus lividus embryos, with concentrations ranging from 0.01 to 3.0 mM. Given the limited size of the available dataset, data augmentation techniques were applied to artificially expand the number of training samples. Subsequently, a convolutional neural network classification model was developed using both original and augmented images, and its performance was assessed using multiple evaluation metrics. The proposed model demonstrated strong performance, achieving a maximum F1 score of 0.976 and an accuracy of 0.988. These results indicate that machine-learning-based approaches can effectively support the classification of sea urchin embryo images even in data-constrained scenarios. Overall, this work contributes to the development of automated and objective methods for morphological assessment, with the potential to enhance both the reliability and efficiency of traditional evaluation procedures. Full article

The red sea urchin Loxechinus albus is a species of high commercial importance in Chilean aquaculture, whose performance is strongly influenced by environmental conditions such as temperature. The gut microbiota plays a central role in host physiology; however, its interaction with stress-induced molecular responses remains poorly understood. This study evaluated the effects of thermal stress on food consumption, gut microbial composition, oxidative status, and immune- and stress-related gene expressions in L. albus gut. Sea urchins were exposed to control (16 °C) and elevated temperature (22 °C) conditions for 7 and 14 days. Gut microbiota was characterized using 16S rRNA sequencing, while oxidative damage to DNA and proteins was quantified. Gene expression analyses targeted markers of apoptosis (casp3, casp10, bak1), cellular growth (mtor, raptor), stress response (hsp70), and immune regulation (nfκb, foxo). Thermal stress induced a marked reduction in microbial alpha diversity and promoted a shift toward opportunistic taxa. Heat-stressed individuals exhibited significantly increased oxidative DNA damage, whereas protein oxidation remained unchanged. Gene expression analyses revealed early upregulation of casp3, casp10, nfκb, foxo, and hsp70, suggesting activation of apoptotic, immune, and stress-response pathways. In contrast, bak1, mtor, and raptor showed limited or no significant modulation. These findings demonstrate that thermal stress disrupts host–microbiota homeostasis and induces oxidative and molecular responses in L. albus. This integrative response provides insight into mechanisms underlying physiological performance under thermal stress, with important implications for aquaculture sustainability. Full article

Paracentrotus lividus (Lamarck, 1816) is a commercially valuable species in the Mediterranean Sea, and the development of suitable feeds for juvenile rearing remains an important challenge for full-cycle aquaculture. In this study, we evaluated two experimental formulated diets containing anchovy-processing by-products and carrot peels as main ingredients, using a commercial diet as control. The diets were tested for 84 days on three size classes of P. lividus under controlled recirculating aquaculture conditions. Growth, feed intake, somatic growth rate, feed conversion ratio, gross apparent digestibility, and nitrogen assimilation were assessed. Our results demonstrated that both experimental diets could sustain the growth of sea urchins. However, growth varied significantly across diets and size classes and the two diets showed different results in terms of somatic growth rate and feed conversion ratio. Our findings suggest that eco-friendly feeds derived from industrial waste by-products can be used for sea urchin aquaculture. However, further research is needed to optimize feeding protocols and understand the underlying mechanisms affecting growth performance and feed assimilation efficiency. The utilization of food waste in aquaculture can contribute to the conservation of overexploited sea urchin stocks and promote sustainable practices in marine resource management. Full article

Glitter is a distinctive and largely overlooked form of primary microplastic. Unlike more commonly studied microplastics, glitter particles are typically flat, highly reflective, multi-layered, and are composed of polymers such as polyethylene terephthalate, polyvinyl chloride with metallic coatings and a wide range of additives. In response to regulatory restrictions on intentionally added microplastics and increasing consumer demand, “eco-friendly” alternatives based on modified regenerated cellulose, cellulose nanocrystals, or mica have been introduced, although their environmental safety remains insufficiently characterized. This review synthesizes current knowledge on the environmental occurrence and ecotoxicological effects of both conventional and biodegradable glitters. A systematic literature search in Scopus identified 15 peer-reviewed experimental studies meeting predefined inclusion criteria. Evidence spans a wide range of taxa, including bacteria (i.e., Aliivibrio fischeri), microalgae and cyanobacteria (i.e., Phaeodactylum tricornutum, Raphidocelis subcapitata, Microcystis aeruginosa), aquatic plants (i.e., Lemna minor, Egeria densa), marine and freshwater invertebrates as crustaceans (i.e., Daphnia magna), bivalves (i.e., Mytilus galloprovincialis), sea urchins (i.e., Paracentrotus lividus), brine shrimp (Artemia sp.) and terrestrial soil fauna (Eisenia fetida, Folsomia candida). Results indicate that glitter cannot be treated as a uniform stressor: biological responses vary markedly with particle size, shape, colour, polymer type, additive composition, and weathering time, and leachates often exert stronger effects than intact particles. Reported impacts include impaired photosynthesis and growth, oxidative stress, developmental abnormalities, altered energy metabolism, and reduced reproduction. Substantial gaps remain regarding environmental concentrations, ageing processes, mixture effects, and long-term ecological consequences, particularly for biodegradable glitters. Addressing these gaps will require realistic exposure scenarios, mesocosm and field studies, and integrated chemical–biological approaches to support robust risk assessment and safer material design. Full article

Real-time visual recognition systems integrated with culturally adaptive reasoning are urgently demanded in globalized culinary scenarios. An agent-oriented framework, Agent-based Gastronomy Recommender Enhanced Engine with YOLO (AGREE-YOLO), is proposed in this study, which integrates an optimized lightweight YOLOv13 detector and vision language model (VLM)-driven agents for cross-cultural seafood recipe recommendation. The improved YOLOv13 is equipped with group shuffle convolution (GSConv) modules and Wise-IoU (WIoU) loss, which is validated on a refined underwater seafood dataset targeting sea cucumbers, sea urchins and scallops. It achieves 91.2% precision and 87.3% recall, with 3.9% and 4.2% increments over the baseline model, and maintains 2.0 ms inference speed. Detection outputs are structured and stored in a MySQL database, and a novel ChatFlow pipeline is constructed in the Dify platform to support natural language database querying. VLM-powered agents retrieve structured data and generate culturally tailored recipes and dish images automatically. Operational validation verifies that the end-to-end pipeline realizes seamless conversion from seafood images to personalized cross-cultural recommendations. This work provides an integrated solution for intelligent, culturally adaptive gastronomy in food informatics. Full article

Sea urchins are invertebrates that play a crucial role in marine ecosystems by controlling benthic algal communities and whose natural populations are being affected by different biotic and abiotic factors. Triggering physiological processes promotes the activation of certain metabolic pathways, so oxidative status markers could be a suitable tool to asses maturation stage in which natural populations are. Antioxidant status of three species of Mediterranean Sea urchins, A. lixula, P. lividus and S. granularis, was evaluated in gonadal and digestive tissue. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione s-transferase (GST), glucose 6-phosphate dehydrogenase (G6PDH), NAD(P)H: quinone oxidoreductase (NQO1) and lipid peroxidation were assayed. Significant differences were found among species, displaying in general higher antioxidant activity in A. lixula and S. granularis compared to P. lividus. A significant effect of sex was observed with females exhibiting a higher gonadosomatic index and higher levels of lipid peroxidation mainly in A. lixula. These results seem to be related to metabolic fluctuations associated with the gonadal maturation stage. Changes in digestive tissue were less evident, but some differences among species could be related to triggered digestive processes for replenishment of energy reserves in gonads. Oxidative status can be a useful complementary tool to evaluate gonadal condition in species of sea urchin from the same habitat. Integrative physiological and biochemical studies will contribute to the knowledge of invertebrate physiology. Full article