Extraction Method Research Articles

Main Characteristics of the Geological Structure of the Evaporite Formation of the Amu Darya Syneclise

The geological structure of the evaporite formation in the Amu Darya syneclise is a complex system that provides valuable insights into the region's geological history and economic potential. The study aims to analyse the main characteristics of the geological structure of the evaporite formation in the Amu Darya syneclise to expand knowledge of the geological and environmental history of the region and to identify the potential of these deposits for various applications. The methods used for this study included geological mapping, mineralogical analysis, stratigraphic analysis and geochemical research. The study identifies three distinct water-bearing horizons within the evaporite complex: Sharaplinsky, Yolotan, and Sakar. These horizons exhibit varying characteristics in terms of composition, water content, and distribution across the basin. Geomorphological manifestations, such as salt lakes and salt marshes, play a crucial role in understanding the ecological and geological history of the region. The evaporite formation holds substantial economic importance, hosting valuable resources including salts, oil, and gas. This geological structure supports regional industrial development, job creation, and overall economic growth. The study also highlights the need for further research into the geology and geomorphology of the Amu Darya syneclise to better understand the formation and dynamics of evaporite deposits and their role in the region’s current environmental and economic sectors. The study emphasizes the need for efficient technologies and methods for resource extraction and management to ensure sustainable development and minimize environmental impact. The research provides crucial data for optimizing mineral extraction strategies and developing effective natural resource management approaches. It underscores the importance of understanding the geological structure for sustainable ecological and economic development in the region. The practical significance of this study is a basis for developing more effective natural resource management strategies based on an understanding of the geological processes of evaporite sedimentation in the Amu Darya syneclise, which is key to the sustainable development of the region’s ecological and economic systems.

Class II (three-layer system) phenomenological model based on limiting current density and dynamic chelation chemistry for separation of rare earth elements using electrodialysis

This paper presents an in-depth investigation into the optimization of rare earth element (REE) separation through electrodialysis, leveraging a newly developed Class II phenomenological model. This study explores the pivotal roles of the HEDTA/Nd molar ratio and pH of feed solution on enhancing the separation efficiency of neodymium (Nd) and praseodymium (Pr) from lanthanum (La) and cerium (Ce). By integrating expanded Nernst-Planck equations and the concept of limiting current density, the model offers a sophisticated understanding of ion transport dynamics and the impacts of concentration polarization. Experimental validation confirms the model’s predictive accuracy, demonstrating its practical applicability for industrial-scale operations. The research delineates how operational parameters such as chelating agent concentration and pH critically influence the purity and yield of separated REEs. The dynamic nature of chelation chemistry is also examined, highlighting its evolution during the electrodialysis process and its effect on the system’s overall performance. Key findings illustrate that lower HEDTA/Nd molar ratios significantly enhance the purity of Nd + Pr by minimizing the chelation of La and Ce, thus facilitating their migration to the concentrate compartment. Conversely, higher ratios maximize yield by retaining more Nd + Pr in the feed compartment. This dual approach allows for optimized separation based on specific industrial requirements. The outcomes of this study not only advance the field of REE separation but also provide a framework for further research into more efficient and sustainable extraction methods. The developed model and its validation represent a step forward in the practical application of electrodialysis in REE processing, offering substantial benefits for the critical materials sector.

13-Week repeated-dose toxicity study of optimized aqueous extract of Moringa oleifera leaves in mice

Ethnopharmacological relevanceMoringa oleifera (Moringaceae family), commonly known as horseradish or tree of life, is traditionally used for various diseases, such as diabetes, hypercholesterolemia, neurological disorders, among others. Aim of the studyTo evaluate the toxicological profile of the oral use of an aqueous extract of Moringa oleifera leaves for 13 weeks in mice. Materials and methodsInitially, a factorial design (23) was carried out to optimize aqueous extraction using as variables; the extraction method and proportion of drug. The 13-week repeated-dose toxicity trial used female and male mice, with oral administration of aqueous extract of Moringa oleifera leaves at doses of 250, 500, and 1000 mg/kg. The animals were evaluated for body weight, water and feed intake, biochemical and hematological parameters, urinalysis, ophthalmology and histopathology of the liver, spleen and kidneys. ResultsThe extraction efficiency was evidenced by the extraction by maceration at 5%, obtaining the optimized extract of Moringa oleifera (OEMo). The oral administration of OEMo did not promote significant difference (p > 0.05) in the weight gain, food and water consumption of the control animals and those treated with 250 and 500 mg/kg. However, treatment with 1000 mg/kg promoted a reduction (p < 0.05) in food intake and body weight from the 7th week onwards in male and female mice. No alterations were detected in the hematological and histological parameters in the concentrations tested for both sexes. The highest concentration treatment (1000 mg/kg) promoted an increase in transaminases in males and females. All concentrations promoted a significant decrease (p < 0.05) in the serum lipid profile of mice. ConclusionThis study developed an optimized extract of Moringa oleifera leaves, which should be used with caution in preparations above 500 mg/kg for the long term because it leads to significant changes in liver enzymes. On the other hand, the extract proved to be a promising plant preparation for hyperlipidemia in mice.

Micro-solid phase extraction with in-lab-packed columns for cost-efficient drug extraction from urine samples

AbstractThis study introduces a miniaturised solid-phase extraction (µ-SPE) method coupled with ultra-high performance liquid chromatography and tandem mass spectrometry (UHPLC-MS/MS) for the simultaneous quantification of 23 compounds, including psychoactive drugs, narcotics and their metabolites, in urine samples. The µ-SPE method, using standard laboratory equipment such as a centrifuge, was developed and validated, offering a practical and economical alternative to more traditional SPE methods. The key extraction parameters: elution solvent composition, sample and elution volumes, and sorbent mass were optimized to enhance performance. The method demonstrated high sensitivity, with detection limits between 0.06 and 0.41 ng cm−3 and quantification limits from 0.19 to 1.24 ng cm−3. The precision was confirmed with an intra-day precision ranging from 0.2% to 7.5% and an inter-day precision from 1.2% to 13.4%. Recovery rates ranged from 84.2% to 109.4%, with minimal matrix effects observed for most analytes (|ME|&lt; 10%). The relative error remained below 5%, indicating good accuracy. The method was also evaluated in terms of greenness, practical, and analytical aspects using the WAC model. Based on the validation results, it was concluded that the developed method could be a good confirmatory method for results obtained by immunochemical tests and could also be used in both clinical analyses and forensic toxicology. Graphical abstract

Effects of Chemical Modification on the Structure and Biological Activities of Polysaccharides Extracted from Inonotus Obliquus by Microwave.

A novel polysaccharide, Inonotus obliquus polysaccharide (IOP), was extracted using a microwave extraction method and subsequently subjected to modifications through sulfation, carboxymethylation, phosphorylation, and acetylation. Its physical and chemical properties were analyzed using various chemical techniques, including high-pressure liquid chromatography, ultraviolet light, Fourier-transform infrared spectroscopy, X-ray diffraction, Congo red test, and scanning electron microscopy. The antioxidant capacity was assessed using DPPH, ABTS, and hydroxyl radical assays, as well as by measuring the reducing power. Additionally, hypoglycemic activity was evaluated through α-glucosidase and α-amylase assays. The results indicated that the chemical modifications effectively altered the physical and chemical properties, as well as the biological activities of IOP. Compared to the unmodified IOP, the derivatives exhibited reduced sugar content, uronic acid content, and molecular weight, while demonstrating varying levels of antioxidant and hypoglycemic capabilities. Notably, the carboxymethylated IOP (IOP-C) displayed lower molecular weight, higher ABTS free radical scavenging rate, greater reducing ability, and increased α-amylase inhibition rate. Therefore, IOP-C shows promise as a potential edible antioxidant and hypoglycemic agent.

Phosphorus speciation in coastal sediment of Osaka Bay: relation to anthropogenic phosphorus loading

Abstract This study assessed the effect of increased anthropogenic phosphorus (P) loading on P speciation in coastal sediments in Osaka Bay, an urbanized enclosed bay, and one of Japan’s most industrialized regions. The study analyzed Total P (TP) and determined the accumulations of five different P species Exchangeable P (Ex-P), Iron-bound P (Fe-P), Calcium-bound P (Ca-P), Detrital P (Det-P) and Organic P (Org-P)in the sediment using the sequential extraction method. We also estimated the historical P loading into Osaka Bay from major river catchments (the Yodo and Yamato Rivers) using the Soil and Water Assessment Tool. This study identified peak P loading values for the Yodo River in 1965 and the Yamato River in 1968, with the Yodo River being the primary anthropogenic source of P inflow for Osaka Bay. The concentration of TP ranges from 290.5 to 353.1 mg Kg−1 respectively, and the order of concentrations of the different P species is Org-P &gt; Det-P &gt; Ca-P &gt; Fe-P &gt; Ex-P. The results indicate a positive relationship between total P loading and Ca-P during the rapid growth period. We examined two potential mechanisms (adsorption-precipitation process and sink switching) for Ca-P formation and hypothesized that the adsorption-precipitation process is the dominant process, indicating that high anthropogenic P loading causes the accumulation of immobile Ca-P species in coastal sediments and serves as a permanent sink for P, as well as for water quality restoration. This result also suggests the possibility of reconstructing historical human-induced P loadings based on Ca-P in coastal sediments.

Prediction of optical properties of oxide glass combined with autoencoder and machine learning

The composition of oxide glasses is characterized by high dimensionality and sparsity, making it challenging to establish high-precision predictive models. Therefore, feature extraction is essential. This study focuses on the optical properties of oxide glasses (refractive index and Abbe number), utilizing autoencoder (AE) and machine learning techniques to achieve automated feature extraction. The results indicate that compared to standalone neural networks (NN), AE-NN transforms unsupervised learning into supervised learning, reducing feature dimensions while improving model accuracy. Specifically, for the refractive index dataset, the dimensionality was reduced from 63 to 25, with a corresponding test set coefficient of determination (R2) of 0.95. For the Abbe number dataset, the dimensionality was reduced from 61 to 30, with a corresponding test set R2 of 0.97, demonstrating the effectiveness of the feature extraction method. Regarding interpretability, analyzing the encoder weight matrix of the AE-NN identified the importance of original features, with Co and Y being the most significant for both refractive index and Abbe number. Additionally, the application of the feature extraction method in machine learning models shows its generality in improving model performance, particularly for non-ensemble models such as Support Vector Regression (SVR) or k-Nearest Neighbors (KNN), exhibiting significant accuracy enhancements. Finally, targeting lanthanide glasses, the established predictive model successfully identified novel optical glasses with high refractive index and Abbe number in the La2O3-Bi2O3 and La2O3-Ta2O5 systems, presenting new possibilities for optical component design.

Development and Application of Novel Extraction Method to Analyze Herbal Supplements and Adulterant Determination by GCxGC/Q-TOFMS

Development and Application of Novel Extraction Method to Analyze Herbal Supplements and Adulterant Determination by GCxGC/Q-TOFMS

Extraction and Characterization of Pectin from Orange Peel

Fruit and vegetable processing waste contributes to around 30% of the total weight of the fruits and vegetables. These wastes can be converted into valuable goods for potential benefits. Therefore, this study was focused on extracting pectin from agricultural waste (orange peels) using two methods: alcohol precipitation and enzymatic extraction. The extracted pectin was compared in terms of various properties. Alcohol precipitation resulted in higher yield percentages (16.99 ± 0.8 % wet; 6.46 ± 1.01 % dry respectively) compared to the enzymatic method (16.84 ± 0.42 % wet; 3.66 ± 0.34 % dry, respectively). FT-IR and XRD spectra indicated the presence of highly methylated semi-crystalline pectin in both methods with potent antioxidant property (40.57%). This research work provides comparative extraction method of pectin from agricultural waste i.e. orange peels which has diverse applications in the food, pharmaceutical industries and biomedical applications.

Production of Fucoxanthin from Microalgae Isochrysis galbana of Djibouti: Optimization, Correlation with Antioxidant Potential, and Bioinformatics Approaches

Fucoxanthin, a carotenoid with remarkable antioxidant properties, has considerable potential for high-value biotechnological applications in the pharmaceutical, nutraceutical, and cosmeceutical fields. However, conventional extraction methods of this molecule from microalgae are limited in terms of cost-effectiveness. This study focused on optimizing biomass and fucoxanthin production from Isochrysis galbana, isolated from the coast of Tadjoura (Djibouti), by testing various culture media. The antioxidant potential of the cultures was evaluated based on the concentrations of fucoxanthin, carotenoids, and total phenols. Different nutrient formulations were tested to determine the optimal combination for a maximum biomass yield. Using the statistical methodology of principal component analysis, Walne and Guillard F/2 media were identified as the most promising, reaching a maximum fucoxanthin yield of 7.8 mg/g. Multiple regression models showed a strong correlation between antioxidant activity and the concentration of fucoxanthin produced. A thorough study of the optimization of I. galbana growth conditions, using a design of experiments, revealed that air flow rate and CO2 flow rate were the most influential factors on fucoxanthin production, reaching a value of 13.4 mg/g. Finally, to validate the antioxidant potential of fucoxanthin, an in silico analysis based on molecular docking was performed, showing that fucoxanthin interacts with antioxidant proteins (3FS1, 3L2C, and 8BBK). This research not only confirmed the positive results of I. galbana cultivation in terms of antioxidant activity, but also provided essential information for the optimization of fucoxanthin production, opening up promising prospects for industrial applications and future research.

Genetic Variation Affects the Anti-Melanogenic Efficacy of Platycodon grandiflorus Flowers

This study investigated the utilization of by-products from Platycodon grandiflorus and the role of genetic diversity in their anti-melanogenic properties, focusing on the purple-flower (PF) and white-flower (WF) varieties. Our results show that the WF variety exhibited significantly higher anti-melanogenic activity, attributed to higher concentrations of key saponins such as platycodin D3 and platycodin D. These saponins demonstrated strong tyrosinase inhibitory effects as confirmed by molecular docking analysis. Further, the WF variety showed increased expression of genes involved in saponin biosynthesis, highlighting the role of genetic diversity in determining phytochemical composition and pharmacological efficacy. The superior anti-melanogenic activity of WF suggests its potential as a valuable ingredient in the cosmetic industry for skin-whitening products. Our findings emphasize the importance of utilizing by-products and selecting specific genotypes to enhance the quality and efficacy of plant-derived products. Future research should explore the full spectrum of bioactive compounds in P. grandiflorus, investigate sustainable extraction methods, and conduct clinical trials to validate the safety and effectiveness of these compounds in cosmetic and therapeutic applications.

FFA-BiGRU: Attention-Based Spatial-Temporal Feature Extraction Model for Music Emotion Classification

Music emotion recognition is becoming an important research direction due to its great significance for music information retrieval, music recommendation, and so on. In the task of music emotion recognition, the key to achieving accurate emotion recognition lies in how to extract the affect-salient features fully. In this paper, we propose an end-to-end spatial-temporal feature extraction method named FFA-BiGRU for music emotion classification. Taking the log Mel-spectrogram of music audio as the input, this method employs an attention-based convolutional residual module named FFA, which serves as a spatial feature learning module to obtain multi-scale spatial features. In the FFA module, three group architecture blocks extract multi-level spatial features, each of which consists of a stack of multiple channel-spatial attention-based residual blocks. Then, the output features from FFA are fed into the bidirectional gated recurrent units (BiGRU) module to capture the temporal features of music further. In order to make full use of the extracted spatial and temporal features, the output feature maps of FFA and those of the BiGRU are concatenated in the channel dimension. Finally, the concatenated features are passed through fully connected layers to predict the emotion classification results. The experimental results of the EMOPIA dataset show that the proposed model achieves better classification accuracy than the existing baselines. Meanwhile, the ablation experiments also demonstrate the effectiveness of each part of the proposed method.

Towards a better understanding of ethylmercury in the environment: Addressing propylation derivatization artifact and verifying its occurrence in Chinese wetlands

Ethylmercury (EtHg), similar to methylmercury (MeHg), is highly neurotoxic and bioaccumulative. Although recent studies suggested its occurrence in natural soils and sediments, the common propylation derivatization for EtHg analysis might generate EtHg artifacts, potentially leading to its overestimation in environmental samples. Furthermore, the extensive environmental prevalence of EtHg remains unverified, keeping its importance largely uncertain. This study investigated the formation of EtHg artifacts during propylation derivatization, evaluating artifacts formation and recoveries under different extraction methods with real samples, and confirmed the widespread occurrence of EtHg in Chinese wetlands. EtHg artifacts were obviously present during the propylation derivatization and strongly dependent on the levels of Hg2+ (0.1–10 ng) in the derivatization solution (R² = 0.99), accounting for 1.38–2.14% of Hg2+. CuSO4-HNO3CH2Cl2 extraction (effectively removing Hg2+) combined with propylation derivatization offers excellent recovery (81–86%) and low artifacts (< LOD: 1.98 × 10−4 ng/g) for EtHg measurement in soils/sediments, with results aligning with those from online solid phase extraction-high performance liquid chromatography-inductively coupled plasma mass spectrometry (R2 = 0.99). Additionally, we observed the occurrence of EtHg in soil and sediment samples across 14 Chinese wetlands, with concentrations varying from 6.08 to 171 pg/g, similar to MeHg concentrations at some sites. EtHg positively correlates with MeHg, total Hg, and total organic carbon across all samples, indicating a possible biological formation. These findings help better understand and predict the prevalence of EtHg in wetlands and its key role in environmental Hg cycle.

Quantitative Comparison of Deparaffinization, Rehydration, and Extraction Methods for FFPE Tissue Proteomics and Phosphoproteomics.

Formalin-fixed paraffin-embedded (FFPE) tissues are suitable for proteomic and phosphoproteomic biomarker studies by data-independent acquisition mass spectrometry. The choice of the sample preparation method influences the number, intensity, and reproducibility of identifications. By comparing four deparaffinization and rehydration methods, including heptane, histolene, SubX, and xylene, we found that heptane and methanol produced the lowest coefficients of variation (CVs). Using this, five extraction methods from the literature were modified and evaluated for their performance using kidney, leg muscle, lung, and testicular rat organs. All methods performed well, except for SP3 due to insufficient tissue lysis. Heat n' Beat was the fastest and most reproducible method with the highest digestion efficiency and lowest CVs. S-Trap produced the highest peptide yield, while TFE produced the best phosphopeptide enrichment efficiency. The quantitation of FFPE-derived peptides remains an ongoing challenge with bias in UV and fluorescence assays across methods, most notably in SPEED. Functional enrichment analysis demonstrated that each method favored extracting some gene ontology cellular components over others including chromosome, cytoplasmic, cytoskeleton, endoplasmic reticulum, membrane, mitochondrion, and nucleoplasm protein groups. The outcome is a set of recommendations for choosing the most appropriate method for different settings.

Phenolic Compounds Synthesized by Trichoderma longibrachiatum Native to Semi-Arid Areas Show Antifungal Activity against Phytopathogenic Fungi of Horticultural Interest

Fungal diseases are a major threat to the horticultural industry and cause substantial postharvest losses. While secondary metabolites from Trichoderma sp. have been explored for their antifungal properties, limited information exists on the phenolic compounds produced by less studied species like Trichoderma longibrachiatum. In this study, phenolic compounds were extracted from a liquid culture of T. longibrachiatum using various solvents and methods (conventional and ultrasonic-assisted). Phenolic compounds were quantified by spectrophotometry and identified by high-performance liquid chromatography with diode array detection (HPLC-DAD). The antifungal activity against Alternaria alternata and Fusarium oxysporum was determined by mycelial growth inhibition assays, maximum growth rate (µmax) by the Gompertz equation, and spore germination tests. Although no significant differences (p ≥ 0.05) were found between the extraction methods, the type of solvent significantly influenced the phenolic content (p ≤ 0.05). Extraction with 70% ethanol showed the highest content of phenolic compounds and flavonoids. More than eight phenolic compounds were detected. Further, this is the first report of the phenolics ferulic, chlorogenic and p-coumaric acids identification in T. longibrachiatum, along with flavonoids such as epicatechin and quercetin, among others. The 70% ethanolic extracts notably inhibited the mycelial growth of A. alternata and F. oxysporum, reducing their maximum growth rate by 1.5 and 1.4 mm/h, respectively. Furthermore, p-coumaric and ferulic acids significantly inhibited spore germination of both pathogens, with a minimum inhibitory concentration (MIC) of 1.5 mg/mL and a minimum fungicidal concentration (MFC) of 2 mg/mL. These findings demonstrate the potential of T. longibrachiatum and its phenolic compounds as viable alternatives for biological control in horticulture and postharvest disease management.

A Rapid, Equipment-Free Method for Detecting Avirulence Genes of Pyricularia oryzae Using a Lateral Flow Strip-Based RPA Assay.

Rice blast, caused by Pyricularia oryzae, is one of the most destructive rice diseases worldwide. Using resistant rice varieties is the most cost-effective way to control rice blast. Consequently, it is critical to monitor the distribution frequency of avirulence (Avr) genes in rice planting fields to facilitate the breeding of resistant rice varieties. In this study, we established a rapid recombinase polymerase amplification-lateral flow dipstick (RPA-LFD) detection system for the identification of AvrPik, Avr-Piz-t, and Avr-Pi9. The optimized reaction temperature and duration were 37°C and 20 min, indicating that the reaction system could be initiated by body temperature without relying on any precision instruments. Specificity analysis showed that the primer and probe combinations targeting the three Avr genes exhibited a remarkable specificity at genus-level detection. Under the optimized condition, the lower detected thresholds of AvrPik, Avr-Piz-t, and Avr-Pi9 were 10 fg/μl, 100 fg/μl, and 10 pg/μl, respectively. Notably, the detection sensitivity of the three Avr genes was much higher than that of PCR. In addition, we also successfully detected the presence of AvrPik, Avr-Piz-t, and Avr-Pi9 in the leaf and panicle blast lesions with the RPA-LFD detection system. In particular, the genomic DNA was extracted using the simpler PEG-NaOH rapid extraction method. In summary, we developed an RPA detection system for AvrPik, Avr-Pi9, and Avr-Piz-t, combined with the PEG-NaOH rapid DNA extraction method. The innovative approach achieved rapid, real-time, and accurate detection of the three Avr genes in the field, which is helpful to understand the distribution frequency of the three Avr genes in the field and provide theoretical reference for the scientific layout of resistant rice varieties.

One-step synthesis of O, P co-doped g-C3N4 under air for photocatalytic reduction of uranium

The photocatalytic reduction of uranium from nuclear wastewater represents a promising method for both uranium extraction and environmental remediation. This approach facilitates the recovery of uranium resources for the nuclear industry while addressing environmental pollution. Despite significant research advancements, there remains a need for cost-effective and environmentally friendly catalytic materials. In this context, we present a two non-metal O, P co-doped g-C3N4 (OPCN) synthesized via a simple one-step thermo-polymerization in air. OPCN demonstrates a high uranium reduction efficiency of 94.9 % under white LED light illumination. Even after five cycles, OPCN maintained a reduction efficiency of 81.7 %, highlighting its stability and reusability. Additionally, OPCN also performs effectively in uranium reduction under natural sunlight and exhibits impressive antimicrobial properties. These features position OPCN as a promising candidate for practical environmental applications.

Rapid Detection of Viral, Bacterial, Fungal, and Oomycete Pathogens on Tomatoes with Microneedles, LAMP on a Microfluidic Chip, and Smartphone Device.

Rapid detection of plant diseases before they escalate can improve disease control. Our team has developed rapid nucleic acid extraction methods with microneedles and combined these with loop-mediated amplification (LAMP) assays for pathogen detection in the field. In this work, we developed LAMP assays for early blight (Alternaria linariae, A. alternata, and A. solani) and bacterial spot of tomato (Xanthomonas perforans) and validated these LAMP assays and two previously developed LAMP assays for tomato spotted wilt virus and late blight. Tomato plants were inoculated, and disease severity was measured. Extractions were performed using microneedles, and LAMP assays were run in tubes (with hydroxynaphthol blue) on a heat block or on a newly designed microfluidic slide chip on a heat block or a slide heater. Fluorescence on the microfluidic chip slides was visualized using EvaGreen and photographed on a smartphone. Plants inoculated with X. perforans or tomato spotted wilt virus tested positive prior to visible disease symptoms, whereas Phytophthora infestans and A. linariae were detected at the time of visual disease symptoms. LAMP assays were more sensitive than PCR, and the limit of detection was 1 pg of DNA for both A. linariae and X. perforans. The LAMP assay designed for early blight detected all three species of Alternaria that infect tomato and is thus an Alternaria spp. assay. This study demonstrates the utility of rapid microneedle extraction followed by LAMP on a microfluidic chip for rapid diagnosis of four important tomato pathogens.

Is it worthy to use environmental DNA instead of scientific trawling or video survey to monitor taxa in soft-bottom habitats?

Non-extractive techniques such as video analysis are increasingly used by scientists to study marine communities instead of extractive methods such as trawling. Currently, environmental DNA (eDNA) analysis is seen as a revolutionary tool to study taxonomic diversity. We aimed to determine which method is the most appropriate to describe fish and commercial invertebrate diversity comparing bottom trawl hauls, video transects and seawater eDNA. Our results reveal that video detected the lowest number of taxa and trawling the highest. eDNA analysis is powerful to describe marine bony fish communities, but some taxa of importance for the ecosystem such as elasmobranchs, crustaceans or molluscs are poorly detected. This may be due to several factors such as marker specificity, incomplete reference gene databases or low DNA release in the environment. For now, the various methods provide different information and none is exhaustive enough to be used alone for biodiversity characterisation.

Oleic acid enriched diet affects the metabolome composition of the hybrid grouper infected with vibriosis.

This study focuses in investigating the fatty acid contents of surviving infected hybrid grouper fed with oleic acid immunostimulant. After a 6-week feeding trial, Epinephelus fuscoguttatus × Epinephelus lanceolatus fingerlings were infected with Vibrio vulnificus. One week after bacterial challenge, fish oil was extracted from body tissue of surviving infected fingerlings using the Soxhlet extraction method. The extracted samples were then sent for GC-MS analysis. The raw GC-MS data were analyzed using software programs and databases (i.e., MetaboAnalyst, SIMCA-P, NIST Library, and KEGG). A total of 39 metabolites were putatively identified, with 18 metabolites derived from the fatty acid group. Our further analysis revealed that most metabolites were highly abundant in the oleic acid dietary samples, including oleic acid (4.56%), 5,8,11-eicosatrienoic acid (3.45%), n-hexadecenoic acid (3.34%), cis-erucic acid (2.76%), and 9-octadecenoic acid (2.5%). Worthy of note, we observed a greater abundance of α-linoleic acid (15.57%) in the control diet samples than in the oleic acid diet samples (14.59%) with no significant difference in their results. The results obtained from this study revealed that surviving infected hybrid grouper expressed more immune-related fatty acids due to the effect of oleic acid immunostimulant. Therefore, in this study, we propose oleic acid as a potential immunostimulant in enhancing fish immunity in aquaculture industry.