Search Results (979)

Accurate determination of cobalamin vitamers in foods remains analytically challenging because conventional cyanidation-based methods convert native cobalamins into cyanocobalamin (CNCbl) and may distort their original distribution. In this study, a cyanide-free UHPLC-MS/MS workflow was developed for the analysis of major cobalamin vitamers in foods, with particular emphasis on preserving native forms during sample preparation. Light, temperature, and cleanup procedures were systematically evaluated. Methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl) showed pronounced light sensitivity, whereas red-light handling better preserved vitamer integrity during pre-analytical operations. A tandem cleanup procedure combining immunoaffinity and Oasis HLB solid-phase extraction improved extract cleanliness in complex food matrices. The workflow showed good chromatographic separation and excellent linearity (R² > 0.999). The validated limits of detection were 0.5 μg/kg for CNCbl, 1.0 μg/kg for AdoCbl, and 0.75 μg/kg for MeCbl. Application to food samples showed no detectable target cobalamins in the tested plant-derived foods, whereas animal liver and oyster samples showed comparatively high levels of the target cobalamin vitamers, with AdoCbl predominating in liver. The proposed workflow may serve as a practical cyanide-free option for exploratory or comparative native-vitamer analysis of CNCbl, AdoCbl, and MeCbl in foods within the current validation scope, particularly when full sets of matched isotope-labeled standards are not readily available. Full article

Oyster aquaculture offers promising opportunities for diversifying marine production in the Romanian Black Sea, where favorable environmental conditions and recent regulatory developments support shellfish farming. This study aimed to generate baseline data for the cultivation of the Pacific oyster, Magallana gigas, through an in situ experimental trial conducted off Mamaia Bay, Romania. A 50 m experimental long-line system was deployed at 13.5 m depth, and triploid oysters were cultured for one year at two depth horizons (3 m and 6 m). The growth performance, meat yield, Condition Index, microbiological quality, environmental parameters, and epibiotic communities were monitored monthly. Cultivation depth significantly influenced oyster growth, with individuals reared at 6 m consistently achieving a greater wet weight and shell length than those at 3 m. Growth rates peaked during spring, and meat yield values indicated good commercial quality. Environmental monitoring showed strong seasonal variability, with high summer temperatures and reduced dissolved oxygen associated with increased mortality. Microbiological analyses revealed higher bacterial loads during warm months. The Condition Index classified the oysters as generally “fine” to occasionally “special”. Overall, the results demonstrate that Black Sea conditions can support successful cultivation of M. gigas, although seasonal environmental stress and epibiosis require appropriate farm management. Full article

Mycelium-based composites (MBCs) have already been applied in various fields, like construction, architecture, packaging, waste management and many others, as sustainable replacement materials. The composites created from such materials are lightweight, biodegradable and can take many different geometrical shapes. As there are many different combinations of fungal mycelium and organic substrates, it is not only important to investigate and determine which of these combinations perform best from an acoustic perspective but also from an environmental point of view. The sound absorption qualities of these biocomposites have been investigated. It was found that the sound absorption coefficients range from 0.33 to 0.49 in the mid-high frequency range for the four different mixtures of substrate and oyster mushroom (Pleurotus ostreatus). The results from the acoustic testing are promising, but the environmental impact of these mycelium-based composites also needs to be determined. The impacts from water and especially from energy, used during the growth and preparation cycles, are the main contributors to the environmental impact of MBCs, which is also confirmed by the relevant literature. A cradle-to-grave life cycle assessment (LCA) was conducted, utilizing the ReCiPe method, with selected environmental impact categories, based on real-world production data and the scientific literature. The results obtained were also compared with a commercially produced acoustical stone wool panel. The influence on environmental impact of the different substrates is also analyzed, determining which MBC is the most environmentally friendly and has the best acoustical properties. Full article

The cement industry contributes approximately 7–8% of global CO₂ emissions, motivating the development of sustainable supplementary materials. This study evaluates the partial replacement (10 wt.%) of Portland cement with calcium carbonate (CaCO₃) derived from oyster shells, both untreated and thermally treated at 600 °C, in non-structural mortar blocks. Structural and physicochemical characterization was performed using XRD, SEM, EDS, BET, and TGA to assess phase composition, morphology, and surface properties. Thermal treatment modified the textural characteristics of CaCO₃, reducing the crystallite size and increasing the specific surface area (from 5.8 to 25.6 m²/g), without phase transformation. Compressive strength results, relative to a reference mortar (13.6 MPa), showed comparable performance, with variations generally within ±10%, although slightly larger deviations were observed for specific particle sizes. Finer calcined particles yielded the highest strength (15.0 MPa), reinforcing the combined influence of particle size and thermal treatment. These results suggest that CaCO₃ acts primarily through a filler effect, improving particle packing and matrix interaction. Both untreated and heat-treated CaCO₃ satisfied strength requirements for non-structural applications, supporting the valorization of oyster shell waste as a sustainable material in cement-based systems. Full article

The rapid accumulation of fruit and vegetable waste and oyster shell residues presents increasing environmental challenges, particularly in regions with intensive agricultural and aquaculture production. This study evaluated the use of oyster shell powder as a calcium-based buffering additive to stabilize acidic fruit and vegetable waste during rearing of black soldier fly larvae (BSFL, Hermetia illucens). Five substrates containing 0, 2, 4, 6, and 8% oyster shell powder (fresh weight basis) were prepared and used for larval rearing under controlled conditions for 12 days. Substrate pH dynamics, larval growth performance, substrate utilization efficiency, and nutritional composition of larval biomass were assessed. Oyster shell supplementation significantly increased substrate pH in a dose-dependent manner, shifting the substrate from strongly acidic conditions toward the range favorable for larval development. Moderate supplementation levels (2–4%) resulted in the highest larval biomass, survival rate, dry matter reduction, and bioconversion efficiency, whereas excessive supplementation reduced performance. Protein content increased at moderate supplementation levels, while lipid content decreased with higher oyster shell inclusion. Calcium concentration in larval biomass increased proportionally with supplementation, whereas essential amino acid composition remained stable. These results demonstrate that oyster shell powder can be used as an effective buffering material to improve the stability of acidic organic waste substrates and enhance BSFL-based bioconversion. The combined utilization of fruit and vegetable waste and oyster shell residues represents a practical approach for integrated waste valorization and supports the development of circular bioeconomy strategies for sustainable protein production. Full article

Understanding the feeding physiological mechanisms of determined oyster species is fundamental for adaptation and growth stabilization, aiming for gains in aquaculture production. To assess its potential for Integrated Multi-Trophic Aquaculture (IMTA) with shrimp, we analyzed the feeding physiology of the mangrove oyster Crassostrea gasar. In this study, we determined the feeding physiology of the mangrove oyster Crassostrea gasar, a commercially important species in tropical Brazil, under two diets, live microalgae (ISO—Isochrysis galbana) and biofloc (BFT), which were tested at four concentrations (10, 20, 30, and 40 mg L⁻¹), to establish whether this species can effectively utilize BFT as a food source. Results indicated that ISO diet promoted superior filtration, characterized by a higher proportion of feces (F), suggesting a reduced need for intensive particle selection. Both clearance (CR) and filtration (FR) rates peaked at 30 mg L⁻¹ before declining, suggesting a physiological threshold for this diet. In contrast, the BFT diet elicited higher CR and FR values but triggered excessive pseudofeces (PF) production and low net organic selection efficiency (NOSE). This suggests high particle rejection and limited nutritional assimilation. In conclusion, while C. gasar can process BFT, it is metabolically disadvantageous as a sole food source. For an optimal performance, I. galbana concentrations should be maintained at or below 30 mg L⁻¹. Full article

Oyster reef restoration projects have been developed to provide habitat for fish and crustaceans. Some novel restoration structures employ greater complexity in attempts to better restore oyster reef habitat along degraded shorelines. The Pervious Oyster Shell Habitat (POSH) was created with greater structural complexity and strength to enhance oyster reef habitat for fish and crustaceans in energetic systems. The purpose of this study was to assess the POSH’s short-term ability to provide oyster reef habitat by measuring utilization of the POSH by fish and decapod crustaceans. Nekton abundances, diversity indices, and community similarity were compared between POSH structures, Reef Innovations’ “Oyster Ball”, and a natural oyster reef control. Artificial reef modules were sampled using 2 m² bottomless lift nets, over one year, along two energetic shorelines in northeast Florida. Fish abundances were low and variable among treatments, with no significant differences detected. Crustacean abundances were greater on the POSH than the Oyster Ball, aside from winter at one site, with significant differences detected for all but two measurements. Nekton community analyses were similar among all treatments and sites. The POSH’s design provided more interstitial space for utilization by common benthic crustaceans. Stakeholders attempting to restore degraded shorelines should consider employing the method. Full article

The complex surface architecture of natural oyster reefs is widely considered to promote biological attachment, yet the underlying mechanisms and the relevance to the design of artificial reefs are not fully understood. Here, we combined field experiments, 3D surface characterization, and numerical modelling to quantify how reef-like roughness regulates biofouling development and near-wall flow around artificial substrates. Surface morphological characteristics of natural oyster reefs were first obtained by 3D scanning and used to fabricate concrete panels with simulated rough textures, while traditional smooth concrete panels served as controls. The two types of panels were simultaneously deployed in the target sea area for a hanging-panel experiment. Samples were collected after 3, 6, 9, and 12 months to track changes in biofouling communities. At each sampling time, the panel surfaces were quantified by canopy roughness ($R_C$), surface heterogeneity ($\sigma$), and fractal dimension ($D$), and these metrics were integrated into numerical simulations combined to resolve the flow field, turbulence kinetic, and near-wall shear stress around the colonized panels. The research results show that, after 12-month immersion, the mean thickness of the biofouling layer on rough and control panels reached 6.39 mm and 5.91 mm, respectively. Rough panels exhibited consistently higher $R_C$ and $\mathsf{\sigma }$ than controls, and these two parameters are strongly linearly correlated ($R^2=0.891)$. Numerical simulations reveal that increased $R_C$ enlarges the oyster settlement shear-stress window (OSSW), indicating more favorable hydrodynamic conditions for oyster settlement and growth on rough panels. Nevertheless, the hydrodynamic differences between the initial rough panels and control panels gradually diminish over time, suggesting that biological growth can progressively naturalize initially smooth substrates. These findings advance the mechanistic understanding of how small-scale roughness and biofouling co-evolve to shape oyster habitat quality and provide a quantitative basis for the eco-engineering design of artificial oyster reefs. Full article

Potentially toxic element (PTE) co-contamination in farmland severely threatens global food safety. To identify effective remediation strategies, large-scale field trials were conducted in two karst regions of Southwest China highly co-contaminated with Cd, Pb, As, Cr, and Hg. The efficacy of seven commercial soil amendments (biochar (BC), fused calcium–magnesium phosphate (FCMP), humic acid (HA), potassium humate (KH), oyster shell powder (OS), composite passivator (PA), and quicklime (QL)) on soil physicochemical properties, PTE bioavailability, maize (Zea mays L.) yield, and plant tissue distribution was systematically evaluated. The results indicated that organic amendments, specifically BC, HA, and KH, consistently outperformed inorganic treatments. These organic materials significantly decreased the diethylenetriaminepentaacetic acid (DTPA)-extractable fractions of cationic PTEs (e.g., Cd and Pb decreased by up to 39.5% under KH treatment) without inadvertently mobilizing As, unlike the alkaline inorganic amendments. This reduction in soil bioavailability closely correlated with improved plant performance, leading to maximum increases in root biomass (up to 130% with BC) and grain yield (up to 27.6% with HA). Furthermore, BC and humic substances effectively restricted PTE accumulation in grains (Cd and Pb reduced by up to 42.1%). Tissue distribution analysis revealed a consistently low root-to-stem translocation factor (TF < 0.2), indicating that roots acted as the primary sink for absorbed PTEs. This study indicates that commercial organic amendments support the use of a superior, broad-spectrum strategy for mitigating multi-PTE risks and ensuring safe agricultural utilization in severely co-contaminated areas. Full article

Among accumulating knowledge of invertebrate immune-like responses, antiviral mechanisms in mollusks remain poorly understood. Pinctada birnavirus (PiBV) infects the mantle epithelial cells of the pearl oyster (Pinctada fucata), causing mass mortality of juveniles during high-temperature periods. Here, we examined immune memory-like responses of pearl oysters to PiBV reinfection. At a high temperature (24–25 °C), experimental infection caused ~80% mortality, whereas mortality remained <30% and did not differ significantly from uninfected controls at a lower temperature (18–20 °C). Juveniles that survived infection at the low temperature and were subsequently reinfected at the higher temperature showed 10% mortality, which was significantly lower than the ~50% observed in naïve oysters infected under the same conditions. At 28 days post-infection at the lower temperature, oysters exhibited gene expression profiles distinct from those of naïve oysters. Ex vivo infection demonstrated significantly reduced PiBV replication in mantle explants from previously infected oysters compared with those from naïve individuals. These findings indicate that P. fucata acquires resistance to PiBV reinfection, and at least part of this resistance is mediated within the mantle, independently of other tissues. Culture supernatants of mantle explants from previously infected oysters were positive for viral genomic RNA even without viral inoculation, suggesting that persistent infection may contribute to the maintenance of immune-like responses. Full article

The spatial distribution of oyster reefs is an important indicator for assessing environmental changes in nearshore fishery habitats. However, due to tidal fluctuations, images of oyster reef distribution acquired under low-light conditions such as early morning or evening often exhibit common issues such as bright spots and shadows. Thermal infrared (TIR) images, which are unaffected by external lighting conditions, can effectively address this problem. Aerial imaging of Liya Mountain, Haimen, Jiangsu Province, China, was conducted in this study. Based on unmanned aerial vehicles (UAVs) imagery acquired in 2025 using multispectral and TIR sensors, the total oyster reef area was estimated to be 6.61 ha. When compared with the oyster reef distribution derived from visible light aerial imagery collected in 2023 under favorable environmental conditions, this represents a decrease of 0.36 ha (5.4%), with the largest individual reef measuring 3388.17 m². To demonstrate the improvement in extraction accuracy achieved by integrating TIR data with multispectral imagery, the research team compared the extraction accuracy for oyster reefs of different sizes: a 1.91% improvement was observed for small reefs, a 9.02% improvement for middle reefs, and an 18.98% improvement for large reefs. Experimentally, the emissivity of oyster reefs was determined to be 0.982 ± 0.002 using an isothermal method in the laboratory. The emissivity derived from in situ measurements showed similar values, supporting the reliability of the laboratory result and providing a crucial parameter for the inversion of reef surface temperature. Experimental results demonstrate that the TIR band can effectively enhance the spatial accuracy of oyster reef measurements under low-light conditions. Full article

Condiment sauces such as soy sauce, fish sauce, oyster sauce, and Worcestershire sauce play a vital role in culinary practices and cultural identity, particularly in the Philippines. These sauces are distinguished by their unique volatile organic compound profiles, which define their aroma and flavor. With the growing demand for these condiment products, there is an increasing need for accurate and efficient methods to classify them, ensuring product authenticity and strengthening quality control. However, conventional approaches such as sensory evaluation and laboratory-based chemical analysis are often expensive, time-consuming, and subjective. To address this limitation, we used an electronic nose (e-nose) system integrated with a Support Vector Machine (SVM) classifier for the classification of dark condiment sauces. The system consists of an array of MQ-series gas sensors connected to an Arduino Mega 2560 for analog-to-digital conversion, with Raspberry Pi 5 serving as the primary processing unit. Sensor data undergo preprocessing steps, including standardization and dimensionality reduction through principal component analysis, before being classified using SVM. A total of 120 samples, consisting of 40 readings per condiment type, were used for training and testing, while 60 additional samples—15 per class—were reserved for validation. The e-nose system achieved a 95% classification performance, as evaluated using a confusion matrix and overall accuracy metrics. These results demonstrate the potential of the e-nose combined with SVM as a reliable tool for condiment classification. The system offers practical applications in quality control and product authentication. Future work may extend its capabilities toward spoilage detection, the integration of different gas sensors, and the classification of a wider variety of condiment sauces. Full article

Background/Objectives: Non-indigenous species are increasingly reshaping Mediterranean marine ecosystems, particularly under ongoing climate warming. The rayed pearl oyster Pinctada radiata, a thermophilic species originating from the Indo-Pacific region, is one of the earliest and most successful invaders in the Mediterranean Sea and has recently established populations in the Adriatic Sea. Methods: This study integrates preliminary shell morphometric data with molecular genetic analyses based on mitochondrial cytochrome c oxidase subunit I (COI) and nuclear internal transcribed spacer 2 (ITS2) markers to confirm species identity and examine patterns of genetic variation in comparison with other Mediterranean Sea regions and the Persian Gulf. Results: Phylogenetic analyses based on COI confirmed P. radiata as a distinct and well-supported monophyletic lineage, whereas the nuclear ITS2 marker showed limited resolution and interspecific overlap. Mediterranean and Adriatic populations showed low COI haplotype and nucleotide diversity and weak genetic structuring, consistent with recent colonization and secondary expansion, whereas Persian Gulf populations were more genetically diverse. Conclusions: Future studies should employ larger sample sizes and broader geographic sampling across both the Mediterranean Sea and the full native range of P. radiata, combined with high-resolution genome-wide nuclear markers, to better resolve connectivity and invasion dynamics. Full article

Bioconversion of lignocellulosic biomass into edible, nutrient-rich products using low-cost forestry waste offers substantial ecological and economic benefits. Composting forestry waste as a substrate for oyster mushroom (Pleurotus ostreatus) cultivation is an effective recovery strategy. However, the specific microbial-driven mechanisms by which nitrogen sources regulate lignocellulose degradation and compost quality during forestry waste composting for Pleurotus ostreatus substrate preparation remain to be elucidated. We evaluated three organic nitrogen sources (bran, soybean meal, and chicken manure) and one inorganic source (diammonium phosphate, DAP) during composting of forest-waste-based substrates. Composting performance and cultivation outcomes were assessed using physicochemical analyses, lignocellulose degradation measurements, high-throughput sequencing of bacterial 16S rRNA and fungal ITS, and biological efficiency. Organic nitrogen sources enhanced compost temperature and lignocellulose degradation by providing sustained nitrogen release, promoting stable colonization of core microbial communities and cooperative bacteria–fungi networks. In contrast, inorganic nitrogen resulted in slower heating, minimal lignocellulose degradation (0.75%), and unstable, competition-dominated microbial networks. Nitrogen sources indirectly shaped microbial communities by regulating the C/N ratio, pH, and electrical conductivity. Lignocellulose degradation and bacterial diversity significantly influenced mushroom biological efficiency, with bacterial diversity strongly regulating degradation rates. The forest waste–bran treatment achieved the highest biological efficiency (78.35%). These findings offer a practical strategy for optimizing forestry waste bioconversion into fungal protein. Full article

Immobilized microorganism technology offers a promising approach for remediating heavy metal-contaminated soils. This study developed a novel bio-mineral composite (B-AM) by coupling acid-modified maifanite (AM) with Bacillus mucilaginosus to enhance lead (Pb) immobilization. Comparative experiments demonstrated that B-AM outperformed conventional amendments, including oyster shell, pristine maifanite, AM and B. mucilaginosus in Pb immobilization. The B-AM treatment optimized soil pH, improved soil fertility with increases in available potassium (1.06-fold) and available phosphorus (1.28-fold). Additionally, B-AM transformed Pb into more stable fractions, reducing labile Pb fractions by 52.52% while increasing the residual fraction by 88.36%. These improvements resulted in an 83.24% reduction in Pb accumulation and a 63.95% increase in the fresh root weight of radish. Mechanistic insights revealed that the enhanced remediation performance stems from both the individual contributions of AM (adsorption capacity) and B. mucilaginosus (biosorption and biomineralization) and their synergistic interaction. Specifically, AM acts as a carrier and pH buffer, promoting microbial proliferation and reducing Pb remobilization from cell lysis. The resulting sustained microbial activity further leads to the formation of stable Pb minerals. Collectively, our results establish a theoretical and practical basis for using B-AM to remediate Pb-contaminated soils. Full article