Molecular characterization, expression and antibacterial function of a macin, HdMac, from Haliotis discus hannai.

Macins are a family of antimicrobial peptides, which play multiple roles in the elimination of invading pathogens. In the present study, a macin was cloned and characterized from Pacific abalone Haliotis discus hannai (Designated as HdMac). Analysis of the conserved domain suggested that HdMac was a new member of the macin family. In non-stimulated abalones, HdMac transcripts were constitutively expressed in all five tested tissues, especially in hemocytes. After Vibrio harveyi stimulation, the expression of HdMac mRNA in hemocytes was significantly up-regulated at 12 hr (P < 0.01). RNAi-mediated knockdown of HdMac transcripts affected the survival rates of abalone against V. harveyi. Moreover, recombinant protein of HdMac (rHdMac) exhibited high antibacterial activities against invading bacteria, especially for Vibrio anguillarum. In addition, rHdMac possessed binding activities towards glucan, lipopolysaccharides (LPS), and peptidoglycan (PGN), but not chitin in vitro. Membrane integrity analysis revealed that rHdMac could increase the membrane permeability of bacteria. Meanwhile, both the phagocytosis and chemotaxis ability of hemocytes could be significantly enhanced by rHdMac. Overall, the results showed that HdMac could function as a versatile molecule involved in immune responses of H. discus hannai.

C-type lectin (CTL) and sialic acid-binding lectin (SABL) from Venerupis philippinarum: Function on PAMP binding and opsonic activities in immune responses.

Lectins are a superfamily of carbohydrate-recognition proteins that bind to specific carbohydrate structures and play significant roles in immune recognition and clearance of invaders. In the study, we investigated the potential mechanisms of PAMP binding and opsonic activities of a c-type lectin and a sialic acid-binding lectin from manila clam Venerupis philippinarum (designed as VpCTL and VpSABL). Both recombinant proteins (rVpCTL and rVpSABL) could bind LPS, PGN, glucan and zymosan in vitro. Coinciding with the PAMPs binding assay, a broad agglutination spectrum was displayed by rVpSABL including gram-positive bacteria Staphyloccocus aureus, gram-negative bacteria Escherichia coli, Vibrio parahaemolyticus, Vibrio harveyi, Pseudomonas putida, Proteus mirabilis and fungi Pichia pastoris, while no agglutinative activities on P. mirabilis and P. putida was observed in rVpCTL. Moreover, the phagocytosis and encapsulation ability of hemocytes could be significantly enhanced by rVpCTL and rVpSABL. More remarkable, VpCTL and VpSABL were highly detected in all the examined tissues, especially in gills and hepatopancreas. All the results showed that VpCTL and VpSABL could function as pattern recognition receptors (PRRs) with distinct recognition spectrum, perhaps involved in the innate immune responses of V. philippinarum.

Endogenous Proteases in Sea Cucumber (Apostichopus japonicas): Deterioration and Prevention during Handling, Processing, and Preservation.

The sea cucumber is an essential nutrient source and a significant economic marine resource associated with successful aquaculture. However, sea cucumbers are highly susceptible to autolysis induced by endogenous protease after postmortem, and the phenomenon of body wall "melting" occurs, which seriously affects the food quality of products and the degree of acceptance by consumers. To satisfy the growing demand for fresh or processed sea cucumbers, we must clarify the autolysis mechanism of sea cucumbers and the methods to achieve autolysis regulation. In this paper, the factors leading to the quality deterioration and texture softening of sea cucumbers are reviewed, with emphasis on enzymatic characteristics, the autolysis mechanism, the effects of autolysis on the physicochemical properties of the body wall of the sea cucumber, and the development of potential natural protease inhibitors. We aim to provide some reference in future preservation and processing processes for sea cucumbers, promote new processing and preservation technologies, and advance the sea cucumber industry's development.

Analyzing toxicological effects of AsIII and AsV to Chlamys farreri by integrating transcriptomic and metabolomic approaches.

Inorganic arsenic (iAs) is a widespread contaminant in marine environments, which is present in two different oxidation states (arsenate (AsV) and arsenite (AsIII)) that have complex toxic effects on marine organisms. The scallop Chlamys farreri (C. farreri) accumulates high levels of As and is a suitable bioindicator of As. In this report, we integrated transcriptomics and metabolomics to investigate genetic and metabolite changes and functional physiological disturbances in C. farreri exposured to inorganic arsenic. Physiological indicators antioxidant factors and cell apoptosis analysis macroscopically corroborated the toxic effects of inorganic arsenic revealed by omics results. Toxic effects of inorganic arsenic on C. farreri were signaling-mediated, causing interference with a variety of cell growth and small molecule metabolism. The results provide evidence that inorganic arsenic disrupts the physiological functions of bivalves, highlighting the correlations between different metabolic pathways and providing new insights into the toxic effects of environmental pollutants on marine organisms.

Sources, bioaccumulation, and toxicity mechanisms of cadmium in Chlamys farreri.

The Potentially toxic elements (PTEs) cadmium (Cd) is one of the most serious stressors polluting the marine environment. Marine bivalves have specific high enrichment capacity for Cd. Previous studies have investigated the tissue distribution changes and toxic effects of Cd in bivalves, but the sources of Cd enrichment, migration regulation during growth, and toxicity mechanisms in bivalves have not been fully explained. Here, we used stable-isotope labeling to investigate the contributions of Cd from different sources to scallop tissues. We sampled the entire growth cycle of Chlamys farreri, which is widely cultured in northern China, from juveniles to adult scallops. We found tissue variability in the bioconcentration-metabolism pattern of Cd in different bound states, with Cd in the aqueous accounting for a significant contribution. The accumulation pattern of Cd in all tissues during growth was more significant in the viscera and gills. Additionally, we combined a multi-omics approach to reveal a network of oxidative stress-induced toxicity mechanisms of Cd in scallops, identifying differentially expressed genes and proteins involved in metal ion binding, oxidative stress, energy metabolism, and apoptosis. Our findings have important implications for both ecotoxicology and aquaculture. They also provide new insights into marine environmental assessment and mariculture development.

Amantadine Toxicity in Apostichopus japonicus Revealed by Proteomics.

Amantadine exposure can alter biological processes in sea cucumbers, which are an economically important seafood in China. In this study, amantadine toxicity in Apostichopus japonicus was analyzed by oxidative stress and histopathological methods. Quantitative tandem mass tag labeling was used to examine changes in protein contents and metabolic pathways in A. japonicus intestinal tissues after exposure to 100 µg/L amantadine for 96 h. Catalase activity significantly increased from days 1 to 3 of exposure, but it decreased on day 4. Superoxide dismutase and glutathione activities were inhibited throughout the exposure period. Malondialdehyde contents increased on days 1 and 4 but decreased on days 2 and 3. Proteomics analysis revealed 111 differentially expressed proteins in the intestines of A. japonicus after amantadine exposure compared with the control group. An analysis of the involved metabolic pathways showed that the glycolytic and glycogenic pathways may have increased energy production and conversion in A. japonicus after amantadine exposure. The NF-κB, TNF, and IL-17 pathways were likely induced by amantadine exposure, thereby activating NF-κB and triggering intestinal inflammation and apoptosis. Amino acid metabolism analysis showed that the leucine and isoleucine degradation pathways and the phenylalanine metabolic pathway inhibited protein synthesis and growth in A. japonicus. This study investigated the regulatory response mechanisms in A. japonicus intestinal tissues after exposure to amantadine, providing a theoretical basis for further research on amantadine toxicity.

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A method for geographical discrimination of Portunus trituberculatus was explored to provide technical support for the protection of geographical indication products and for tracing the origin of seafood. P. trituberculatus were collected from three major production areas, including the Yellow Sea, the Bohai Sea, and the East China Sea. The variations of carbon and nitrogen stable isotope values of origins and the correlation of stable isotope ratios in different tissues were analyzed. The results showed that there were significant differences in carbon and nitrogen stable isotope ratio among different origins. Significant isotope fractionation effects were observed among different tissues. The discriminant model was developed and the origin discriminant analysis was performed by the stable isotope ratios of different tissues in P. trituberculatus. The correct rate of origin diffe-rentiationf using carbon and nitrogen stable isotopes in muscle and gills (>95%) was significantly higher than that of hepatopancreas and gonad, indicating that stable isotope ratios of muscle and gills could effectively differentiate P. trituberculatus in different sea areas. This study filled the gap of stable isotope tracing technology for P. trituberculatus.

Metabolomics comparison of metabolites and functional pathways in the gills of Chlamys farreri under cadmium exposure.

The biological processes of Chlamys farreri (C. farreri), an economically important shellfish, are affected when exposed to Cd2+. In this study, changes to biological processes and metabolite levels in C. farreri were examined when exposed to Cd2+. Ultra-performance liquid chromatography-tandem TOF mass spectrometry (UPLC-TOF/MS)-based untargeted metabolomics was used to examine changes in the metabolism of C. farreri gill tissue exposed to 0.050 mg/L Cd2+ for 96 h in a natural environment. Sixty-eight metabolites with significant differences were screened by multivariate statistical analysis. Eleven enriched functional pathways displayed significant changes in inactivity. Differential metabolites, mainly C00157 and C00350, have a significant impact on functional pathways and can be used as potential major biomarkers. Lipid phosphorylation, disruption of signal transduction, and autophagy activation were observed to change in C. farreri when exposed to Cd. The metabolome information supplements research on C. farreri exposure to heavy metals and provides a platform for further multi-omics analysis.

Metabolomic Alterations in the Digestive System of the Mantis Shrimp Oratosquilla oratoria Following Short-Term Exposure to Cadmium.

Mantis shrimp Oratosquilla oratoria is an economically critical aquatic species along the coast of China but strongly accumulates marine pollutant cadmium (Cd) in its digestive system. It is necessary to characterize the toxicity of Cd in the digestive system of mantis shrimp. The metabolic process is an essential target of Cd toxicity response. In this work, we used ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOF-MS) for untargeted metabolomics to characterize the metabolic changes in the digestive system of O. oratoria, exposed to 0.05 mg/L for 96 h. The aim of this study was to further investigate the effect of O. oratoria on Cd response to toxicity and develop biomarkers. Metabolomics analysis showed the alteration of metabolism in the digestive system of mantis shrimp under Cd stress. A total of 91 metabolites were differentially expressed and their main functions were classified into amino acids, phospholipids, and fatty acid esters. The enrichment results of differential metabolite functional pathways showed that biological processes such as amino acid metabolism, transmembrane transport, energy metabolism, and signal transduction are significantly affected. Based on the above results, the Cd-induced oxidative stress and energy metabolism disorders were characterized by the differential expression of amino acids and ADP in mantis shrimp, while the interference of transmembrane transport and signal transduction was due to the differential expression of phospholipids. Overall, this work initially discussed the toxicological response of Cd stress to O. oratoria from the metabolic level and provided new insights into the mechanism.

Analysis of amantadine in Laminaria Japonica and seawater of Daqin Island by ultra high performance liquid chromatography with positive electrospray ionization tandem mass spectrometry.

A sensitive and validated method for determination of amantadine in Laminaria Japonica and seawater was established using ultra high performance liquid chromatography with positive electrospray ionization tandem spectrometry (UHPLC-ESI-MS/MS). Laminaria Japonica was extracted with acetonitrile containing formic acid (1%), then purified with 10.0 g anhydrous sodium sulfate, 0.50 g C18 and 0.50 g PSA powder. Seawater added 10.0 mL 0.20 mol/L hydrochloric acid was purified with MCX solid phase extraction (SPE) cartridge. After extraction and purification, the supernatant of Laminaria Japonica and eluate of seawater were evaporated to nearly dry under a gentle stream of nitrogen at 40 °C. Acetonitrile-0.1% formic acid in water (3/7, v/v) was adjusted to 1.00 mL final volume. An aliquot (10 µL) was injected into the C18 column for separation with the mobile phase of acetonitrile and 0.1% formic acid in water at 0.25 mL·min-1. Calibration curves were linear ranged from 1.00 ng/mL to 20.0 ng/mL. Mean recoveries were 73.5% to 95.8%, and limit of detection (LOD) and quantification (LOQ) were 0.50 µg/kg and 1.00 µg/kg for Laminaria Japonica. Mean recoveries were 75.8% to 93.4%, and LOD and LOQ were 0.50 ng/L and 1.00 ng/L for seawater. Based on the method above, Laminaria Japonica and seawater in Daqin Island were analyzed in February to June continuously, lgBAF3.71 (bioaccumulation factor), indicating a bioenrichment effect.

Application of capillary electrophoresis to study phenolic profiles of honeybee-collected pollen.

Honeybee-collected pollen is promoted as a health food with a wide range of nutritional and therapeutic properties. A high-performance capillary electrophoresis with amperometric detection method has been developed for the simultaneous determination of bioactive ingredients in 10 samples of honeybee-collected pollen in this work. Under the optimum conditions, 13 phenolic components can be well-separated or nearly baseline-separated (apigenin and vanillic acid peaks) within 29 min at the separation voltage of 14 kV in a 50 mM borax running buffer (pH 9.0), and adequate extraction was obtained with ethanol for the determination of the above 13 compounds. Recovery (94.1-104.0%), repeatability of the peak current (<5.4%), and detection limits (6.9 x 10(-7)-6.4 x 10(-9) g mL(-1)) for the method were evaluated. This procedure was successfully used for the analysis and comparison of the phenolic content of honeybee-collected pollen samples originating from different floral origins based on their electropherograms or "phenolic profiles".

Environmental status and early warning value of the pollutant Semicarbazide in Jincheng and Sishili Bays, Shandong Peninsula, China.

A verified method for measuring Semicarbazide (SEM) in seawater, sediments, and shellfish was developed based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A total of 30 stations were radially distributed in Jincheng and Sishili Bays in the Bohai and Yellow Seas, and 1025 monitoring data were collected in 41 voyages, 615 seawater samples, 320 sediment samples and 90 shellfish samples. The concentration ranged from 0.011µg/L to 0.093µg/L and 0 to 0.75µg/kg in seawater and shellfish respectively, but SEM in sediment was all below the limit of detection. Temporal and spatial distribution of SEM was investigated using multivariate analysis to estimate the degree of SEM pollution. Based on the SEM concentration in the three sample types, together with our previous findings, early warning values were deduced for SEM in seawater, and the developed method overcame shortcomings with existing technologies. The results may be helpful to draft national baseline values for SEM in seawater and sediments, and provide a scientific basis for assessing the impacts of SEM on marine ecology and human health.

Study on capillary electrophoresis-amperometric detection profiles of different parts of Morus alba L.

A high-performance capillary electrophoresis with amperometric detection (CE-AD) method has been developed for the determination of the pharmacologically active ingredients in different parts of Morus alba L. after a relatively simple extraction procedure. This method was also used in the comparison of bioactive constituent difference in the five parts, based on their electropherograms or characteristic "CE-AD profiles". The effects of several factors such as the acidity and concentration of running buffer, separation voltage, applied potential and injection time were investigated to find the optimum conditions. Method detection limits (S/N = 3) ranged from 1.5 x 10(-7) to 1.4 x 10(-8)g/mL for all 10 analytes, and the assay results were satisfactory.

Electromigration profiles of Cynomorium songaricum based on capillary electrophoresis with amperometric detection.

A high-performance capillary electrophoresis with amperometric detection (CE-AD) method has been developed for the simultaneous determination of the pharmacologically active ingredients in Cynomorium songaricum in this work. Under the optimum conditions, phloridzin, epicatechin, catechin, naringenin, rutin, luteolin, quercetin, gallic acid, and protocatechuic acid can be well separated or nearly baseline separated (epicatechin and catechin peaks) within 31 min at the separation voltage of 14 kV in a 50 mmol L(-1) Borax running buffer (pH 9.0). Detection limits (S/N=3) ranged from 5.7 x 10(-8) to 8.5 x 10(-9) g mL(-1) for all nine analytes. This procedure was successfully used for the analysis and comparison of the content difference of C. songaricum samples collected from different places based on their electrophorograms or "electromigration profiles".

Temporal and spatial distribution of semicarbazide in western Laizhou Bay.

Semicarbazide (SEM), an industrial raw material and the marker residue of nitrofurazone as a veterinary drug, has become a new type of marine pollutant. A standard method (ultra-performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS) was used to analyze SEM in seawater, sediment, and shellfish. A series of sections and stations were set up in radical distribution in western Laizhou Bay, with six voyages and 150 monitoring samples. The concentrations of SEM in seawater and shellfish were 10-11 and 10-10kg/L, respectively, and no SEM was detected in the sediment. Distribution characteristics at each state, temporal and spatial trends, multivariate analyses, and the causes were analyzed to assess the pollution level, which aimed to offer a database for drafting the national baseline values of SEM in seawater and sediment in future. The data obtained could be used for integrated watershed management of marine environment and economic activities for constructing a blue economic zone of Shandong Peninsula in China.

Analysis of colistin A and B in fishery products by ultra performance liquid chromatography with positive electrospray ionization tandem mass spectrometry.

A rapid and simple method for the determination of colistin A and B in fishery products by reversed phase ultra performance liquid chromatography with positive electrospray ionization tandem spectrometry (UPLC-ESI-MS/MS) method was described. The samples were extracted with 1.0 mol/L of hydrochloric acid in methanol-water and then purified on the PLS solid phase extraction columns. Then the eluate was evaporated to less than 1 mL under a gentle stream of nitrogen at 40 °C and formic acid-acetonitrile-water (0.2/10/90, v/v/v) was added to adjust volume to 1 mL final volume. An aliquot (10 µL) was injected onto the LC column for analysis with the mobile phase of 0.2% formic acid in acetonitrile and 0.2% formic acid in water at 0.20 mL min⁻¹. Multiple reaction monitoring was performed using precursor-product ion combinations. Calibration curves were linear from 200 ng/mL to 2000 ng/mL for colistin A and B. Mean recoveries were between 72.9% and 82.9%. The LOD was 10.0 µg/kg and LOQ was 40.0 µg/kg. The intra-day assay precision values for QC samples were between 2.17% and 9.00%, and inter-day values were between 2.80% and 6.97%. The method has merits of simplicity, sensitivity and rapidity, and it can be used for the determination of colistin A and B in fishery products.

Simultaneous determination of malachite green, crystal violet, methylene blue and the metabolite residues in aquatic products by ultra-performance liquid chromatography with electrospray ionization tandem mass spectrometry.

This work describes solid-phase extraction-ultra-performance liquid chromatography with electrospray ionization tandem spectrometry for determination of malachite green and metabolite leucomalachite green, crystal violet and metabolite leucocrystal violet, methylene blue and metabolites including azure A, azure B and azure C in aquatic products. Samples were extracted with acetonitrile and ammonium acetate buffer and purified by liquid extraction with dichloromethane, and then on MCAX solid-phase extraction cartridges. Then the extract was evaporated at 45°C by nitrogen blow. The residue was dissolved and separated by an Acquity BEH C18 column. The mobile phase was acetonitrile (A) and 5 mmol/L of ammonium acetate containing 0.1% formic acid (B). Analytes were confirmed and quantified using a tandem mass spectrometry system in multiple reaction mode with triple quadrupole analyzer using positive polarity mode. The limits of detection of malachite green, leucomalachite green, crystal violet and leucocrystal violet were 0.15 µg/kg, the limits of quantification were 0.50 µg/kg, and the average recoveries were more than 75% with spiked residues from 0.5 to 10 µg/kg. The relative standard deviations were less than 13%. The limits of detection of methylene blue, azure A, azure B and azure C were 0.3 µg/kg, the limits of quantification were 1.0 µg/kg, the average recoveries were more than 70% with spiked residues from 1.0 to 10 µg/kg and the relative standard deviations were less than 15%. The method has the merits of simplicity, sensitivity and rapidity, and can be used for simultaneous determination of the analytes in aquatic products.

Rapid determination of acetaminophen and p-aminophenol in pharmaceutical formulations using miniaturized capillary electrophoresis with amperometric detection.

Capability of fast analysis of a novel miniaturized capillary electrophoresis with carbon disk electrode amperometric detection (mini-CE-AD) system was demonstrated by determining acetaminophen and p-aminophenol in dosage forms. Factors influencing the separation and detection processes were examined and optimized. Under the optimum conditions, the end-capillary 300 microm carbon disc electrode amperometric detector offered favorable signal-to-noise characteristics at a relatively low potential (+600 mV versus Ag/AgCl) for detecting acetaminophen and p-aminophenol. Two analytes can been separated within 150 s in a 8.5 cm length capillary at a separation voltage of 2000V using a Na2B4O7-KH2PO4 running buffer (pH 7.2). Acetaminophen and p-aminophenol could be detected down to the 1.4 x 10(-6)-5.9 x 10(-7) molL(-1) level with linearity up to the 1.0 x 10(-3) molL(-1) level examined. The inter-day repeatability for analytes in peak current (R.S.D.< or =2.3%) and migration times (R.S.D.< or =1.3%) were excellent. The proposed mini-CE-AD system should find a wide range of analytical applications in pharmaceutical formulations as an alternative to conventional CE and mu-CE.

Determination of active ingredients in corn silk, leaf, and kernel by capillary electrophoresis with electrochemicaI detection.

Corn has been known for its accumulation of flavones and phenolic acids. However, many parts of corn, except kernel, have not drawn much attention. In this work, a method based on capillary zone electrophoresis with electrochemical detection has been used for the separation and determination of epicatechin, rutin, ascorbic acid (Vc), kaempferol, chlorogenic acid, and quercetin in corn silk, leaf, and kernel. The distribution comparison of the ingredients among silk, leaf, and kernel is discussed. Several important factors--including running buffer acidity, separation voltage, and working electrode potential--were evaluated to acquire the optimum analysis conditions. Under the optimum conditions, the analytes could be well separated within 19 min in a 40-mmol/L borate buffer (pH 9.2). The response was linear over three orders of magnitude with detection limits (S/N = 3) ranging from 4.97 x 10(-8) to 9.75 x 10(-8) g/mL. The method has been successfully applied for the analysis of corn silk, leaf, and kernel with satisfactory results.