Investigating the levels, spatial distribution, and trophic transfer patterns of short-chain chlorinated paraffins in the Southern Bohai Sea, China.

The marine environment of the southern Bohai Sea is severely polluted by short-chain chlorinated paraffins (SCCPs). To improve understanding of how SCCPs occur and of how they migrate, are transformed, and transferred in this area, we collected seawater, sediment, and organism samples, and determined the SCCP contents using a new approach based on high-resolution mass spectrometry. The ΣSCCP concentrations in the seawater, sediment, and organism samples ranged from 57.5 to 1150.4 ng/L, 167.7-1105.9 ng/g (dry weight), and 11.4-583.0 ng/g (wet weight), respectively. Simulation of the spatial distribution of SCCPs using Kriging interpolation showed that SCCPs were markedly influenced by land-based pollution. Substantial quantities of SCCPs were transported to the marine environment via surface runoff from rivers that passed through areas of major SCCP production. Once discharged from such rivers into the Bohai Sea, these SCCPs were further dispersed under the influence of ocean currents. Furthermore, the logarithmic bioaccumulation factor that varied from 2.12 to 3.20 and the trophic magnification factor that reached 5.60 (r2 = 0.750, p < 0.01) suggest that organisms have the ability to accumulate and biomagnify SCCPs through the food chain, which could potentially present risks to both marine ecosystems and human health.

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.

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.

Rapid removal of chloramphenicol via the synergy of Geobacter and metal oxide nanoparticles.

The wide use of chloramphenicol and its residues in the environments are an increasing threat to human beings. Electroactive microorganisms were proven with the ability of biodegradation of chloramphenicol, but the removal rate and efficiency need to be improved. In this study, a model electricigens, Geobacter metallireducens, was supplied with and Fe3O4 and MnO2 nanoparticles. Five times higher chloramphenicol removal rate (0.71 d-1) and two times higher chloramphenicol removal efficiency (100%) was achieved. Fe3O4 and MnO2 nanoparticles highly increased the current density and NADH-quinone oxidoreductase expression. Fe3O4 nanoparticles enhanced the expression of alcohol dehydrogenase and c-type cytochrome, while MnO2 nanoparticles increased the transcription of pyruvate dehydrogenase and Type IV pili assembly genes. Chloramphenicol was reduced to a type of dichlorination reducing product named CPD3 which is a benzene ring containing compound. Collectively, Fe3O4 and MnO2 nanoparticles increased the chloramphenicol removal capacity in MFCs by enhancing electron transfer efficiency. This study provides new enhancing strategies for the bioremediation of chloramphenicol in the environments.

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.

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.

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.

UPLC-MS/MS Method for Simultaneous Determination of Three Major Metabolites of Mequindox in Holothurian.

This study developed an ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the detection of three major metabolites of mequindox, including 3-methyl-quinoxaline-2-carboxylic acid, 1-desoxymequindox, and 1,4-bisdesoxymequindox (MQCA, 1-DMEQ, and BDMEQ), in holothurian. Target analytes were simplified with ultrasound-assisted acidolysis extracted without complicated enzymolysis steps. After that, each sample was centrifuged and purified by an Oasis MAX cartridge. Then, the processed samples were separated and monitored by UPLC-MS/MS. This developed method has been validated according to FDA criteria. At fortified levels of 2, 10, and 20 µg/kg, recoveries ranged from 82.5% to 93.5% with the intraday RSD less than 7.27% and interday RSD less than 11.8%. The limit of detection (LOD) of all the three metabolites ranged from 0.21 to 0.48 µg/kg, while the limit of quantification (LOQ) ranged from 0.79 to 1.59 µg/kg. On application to commercial samples, 14 of 20 samples were detected positive for the three target analytes, with positive rate at 70 percentage. The result indicated that this method was specific, sensitive, and suitable for the quantification and conformation of the three major metabolites of MEQ in holothurian.

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.