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The wide application of nanoparticles will lead its release into the aquatic environment, which may alter the bioavailability and toxicity of other contaminants to aquatic organisms. This work aimed to study the effects of perfluorooctane sulfonate (PFOS), single-wall carbon nanotubes (SWCNT), and their mixture on PFOS accumulation, antioxidant defenses and acetylcholinesterase (AChE) activity in zebrafish. The fish was dissected after being exposed (24, 48, 72 and 96 h) separately to PFOS, SWCNT and PFOS + SWCNT co-exposure. The bioaccumulation of PFOS in fish tissues (liver, intestines, gills and brain) decreased with increasing dosage of SWCNT, however, the opposite trend was observed in fish skin, which indicated that the bioavailability of PFOS changed by adsorption on SWCNT. Meanwhile, co-exposure induced more reactive oxygen species (ROS) than PFOS alone and enhanced the effect of PFOS on the superoxide dismutase (SOD), and catalase (CAT) and AChE activities. Furthermore, the integrated biomarker response (IBR) showed that co-exposure was the most stressful circumstance. [ABSTRACT FROM AUTHOR]

Early post-harvest processes, from on-board handling to land-based depuration, is considered as the quality determination period (QDP) of bivalves. Hypoxic stress induced by air exposure is one of the most severe stresses during the QDP. In the present study, a metabolomics analysis based on ultra-performance liquid chromatography quadrupole-TOF mass spectrometry (UPLC-Q-TOF-MS) was performed to characterize the metabolic changes in emersed scallops (Mizuhopecten yessoensis) during the QDP and the metabolic regulation after reimmersion. A total of 34 differentially abundant metabolites between the control and emersion groups were identified, including 6 down-regulated and 28 up-regulated; these metabolites were involved in the pentose phosphate pathway, glyoxylate and dicarboxylate metabolism, and biosynthesis of unsaturated fatty acids. Additionally, disturbances in energy metabolism, the osmotic regulation system and membrane fluidity also occurred in emersed scallops. Among the discriminant metabolites, 13 metabolites were significantly regulated after reimmersion and can be considered biomarkers for scallop quality assurance. Moreover, the pH, glycogen and ATP-related compound levels of scallops were changed under air exposure conditions but recovered after reimmersion. The results show that this metabolomics approach could be used as a new strategy for investigating metabolic variations in scallops to reveal the effects of post-harvest hypoxic stress on freshness quality. This study indicates that air exposure is a feasible, simple and convenient method that can be used in early post-harvest handling during the QDP without causing irreversible physiological disruption to scallops. • The physiological disorder of scallops under emersion and metabolism regulation after reimmersion. • Biomarkers were used to reflect the quality of live scallops. • A untargeted metabolomics based on UPLC-Q-TOF-MS apply in quality control of live scallops. • Air exposure in early post-harvest handling would not cause irreversible physiological disruption to scallops. [ABSTRACT FROM AUTHOR]

Yogurt and its related products are popular worldwide. During transportation and storage, Lactobacillus delbrueckii ssp. bulgaricus in yogurt continues to metabolize to form lactic acid, the postacidification phenomenon of yogurt. Postacidification of yogurt is a widespread phenomenon in the dairy industry. Many scholars have done research on controlling the postacidification process, but few report on the molecular mechanisms involved. In this study, we used a molecular-assisted approach to screen food additives that can inhibit postacidification and analyzed its effects on yogurt quality as well as its regulatory mechanism from multi-omics perspectives in combination. The copper ion was found to upregulate the expression of the LDB_RS05285 gene, and the copper transporter-related genes were regulated by copper. Based on the metabolic-level analysis, copper was found to promote lactose hydrolysis, accumulate a large amount of glucose and galactose, inhibit the conversion of glucose to lactic acid, and reduce the production of lactic acid. The significantly greater abundance of l -isoleucine and l -phenylalanine increased the abundance of 3-methylbutyraldehyde (∼1.2 times) and benzaldehyde (∼7.9 times) to different degrees, which contributed to the formation of the overall flavor of yogurt. Copper not only stabilizes the acidity of yogurt, but also it improves the flavor of yogurt. Through this established method involving quantitative and correlation analyses at the transcriptional and metabolic levels, this study provides guidance for the research and development of food additives that inhibit postacidification of yogurt and provide a reference for studying the changes of metabolites during storage of yogurt. [ABSTRACT FROM AUTHOR]

From on-board handling to land-based depuration, scallops are subject to various stresses. Mechanical shock is one of the unavoidable factors of post-harvest handling. In this research, a metabolomics strategy based on ultra performance liquid chromatography–mass spectrometry (UPLC-MS) was used to investigate the metabolic characteristics of live scallops (Mizuhopecten yessoensis) subjected to mechanical shock. Phosphoarginine and ATP-related compound levels were also measured to understand the metabolic disturbances. Live scallops maintained in a circulating seawater system for 36 h formed the control group, while those individuals dropped 15 times onto a hard surface from a height of 1 m before being maintained in a circulating seawater system formed the shock group. Samples were collected from the adductor muscles, and multivariate statistical analyses were performed to identify the potential biomarkers of mechanical shock due to post-harvest handling. Our results suggested that obvious metabolic disturbances occurred when scallops suffered mechanical shock during post-harvest handling. A total of 18 biomarkers were identified, including 10 upregulated and 8 downregulated biomarkers. Pathway enrichment analysis showed that the biosynthesis of amino acids and cysteine and methionine metabolism were prone to interference when M. yessoensis was subjected to mechanical shock during early post-harvest handling. This study provides a new perspective into the metabolic profiles of scallops subjected to various stressors and can assist in the improvement of disposal methods of post-harvest scallops. • Mechanical shock is one of the unavoidable factors of post-harvest handling. • Biomarkers were used to reflect the quality of live scallops. • A untargeted metabolomics based on UPLC-Q-TOF-MS apply in quality control of live scallops. • The mechanical shock of post-harvest handling would cause irreversible physiological disruption to scallops, and it is closely related to the flavor loss. [ABSTRACT FROM AUTHOR]

Abstract Organic matter (OM) is an important component of sediment. Bioturbation/bioirrigation can remobilize OM and heavy metals that were previously buried in the sediment. The remobilization of buried organic matter, thallium (Tl), cadmium (Cd), copper (Cu) and zinc (Zn) from sediment was studied in a laboratory experiment with three organisms: tubificid, chironomid larvae and loach. Results showed that bioturbation/bioirrigation promoted the release of dissolved organic matter (DOM) and dissolved Tl, Cd, Cu and Zn, but only dissolved Zn concentrations decreased with exposure time in overlying water. The presence of organisms altered the compositions of DOM released from sediment, considerably increasing the percentage of fulvic acid-like materials (FA) and humic acid-like materials (HA). In addition, bioturbation/bioirrigation accelerated the growth and reproduction of bacteria to enhance the proportion of soluble microbial byproduct-like materials (SMP). The DOM was divided into five regions in the three-dimensional excitation emission matrix (3D-EEM), and each part had different correlation with the dissolved heavy metal concentrations. Dissolved Cu had the best correlation with each of the DOM compositions, indicating that Cu in the sediment was in the organic-bound form. Furthermore, the organism type and heavy metal characteristics both played a role in influencing the remobilization of heavy metal. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

The wheat pericarp is the main component of the caryopsis at the early development stage and ultimately converts into a tissue that covers the mature caryopsis. A large number of starch granules are accumulated in the pericarp, but the production of and the role of starch granules in caryopsis development remain- elusive. In the present study, the relationship between accumulated starch granules and starch metabolism-related genes in wheat pericarp was investigated using paraffin section observations, expression analysis, and mutant analysis. Starch synthesis is initiated before anthesis and is dependent on a sucrose uptake and conversion system similar to that in the endosperm. TaPTST2 is required to initiate the production of pericarp starch granules. Pericarp starch granules gradually disappeared at the filling stage with high expression levels of genes encoding β-amylase, sucrose-phosphate synthase, and sucrose-phosphate phosphatase. As a maternal tissue adjacent to the endosperm and embryo, the pericarp plays a temporary reservoir for excess nutrients delivered into the caryopsis during the early development stage and exported at the filling stage. The pericarp contributes to the development of the endosperm and embryo as well as the accumulation of endosperm starch. The metabolism of pericarp starch may affect the weight of the wheat caryopsis. • Pericarp cell possesses a complete starch metabolism system. • TaPTST2 promotes the initiation of pericarp starch granule. • Pericarp acts as a temporary reservoir for nutrients delivered into the young caryopsis. [ABSTRACT FROM AUTHOR]

Bioturbation/bioirrigation can affect the remobilization of metals from sediments. In this study, experiments were performed to examine the effect of bioturbation/bioirrigation by different organisms on cadmium (Cd), copper (Cu), zinc (Zn) and lead (Pb) releasing from the spiked sediment. The diffusive gradient in thin films technique (DGT) revealed that at the end of exposure time, the labile heavy metals concentrations in the pore water for all metal and organisms combinations except Cu and chironomid larvae were much lower than that in the control group. However, the concentrations of heavy metals detected by the DGT were virtually indistinguishable among the treatments with tubificid, chironomid larvae and loach. The correlation analysis of heavy metals with iron (Fe) and manganese (Mn) suggested that Cd, Zn and Pb were most likely bound as Fe-Mn oxidation form in the pore water, but Cu was in other forms. After 28 d of exposure, bioturbation/bioirrigation produced a significant release of particulate heavy metals into the overlying water, especially in the treatment with loach. The bioturbation/bioirrigation impact on the Pb remobilization was less than the other three heavy metals. The effects of bioturbaiton/bioirrigation on the heavy metals remobilization in the sediment were complex that with studying the heavy metals remobilization in the sediment and water interface, the biological indicators should be recommended. [ABSTRACT FROM AUTHOR]

In this work, boron doped graphene quantum dots (BGQDs) with the atomic percentage of boron (B) of 0.67-2.26% were synthesized by electrolytic exfoliation of B doped graphene rods. X-ray photoelectron spectroscopy of BGQDs confirmed that the B atoms have been successfully incorporated into the GQDs. Characterizations by transmission electron microscopy, photoluminescence (PL) spectra and UV-visible spectra demonstrated that BGQDs had a consistent lattice spacing with the plane of graphene and possessed good luminous performance. The PL stability, the electrochemical impedance and Zeta potential test indicated that the 60 days-PL stability of BGQDs was improved by 51% and the resistance of BGQDs was decreased by 11% compared with that of the pure GQDs when 1.29% (atomic percentage) of B was doped. Electrochemiluminescence (ECL) sensing results showed that the ECL sensor with BGQDs as luminescent material exhibited an excellent analytical property for the detection of miRNA-20a in a linear range of 0.1-1×10 4 pM with a quantification limit of 0.1 pM. Specificity tests showed that this ECL sensor could distinguish the target miRNAs-20a with several similar bases strand. The obtained results in this study prove that the proposed ECL sensor provides a high sensitively, specifically and simply platform for detection of miRNAs-20a. [ABSTRACT FROM AUTHOR]

Sucrose, the main synthesized product and transported form of photoassimilates, moves from leaves to support plant growth and storage substance biosynthesis occurring in the heterotrophic sink organs. Enhancing sucrose biosynthesis efficiency is a top priority for crop yield breeding programs. However, the molecular mechanism of sucrose biosynthesis is still elusive, especially in wheat. We performed transcriptome sequencing, subcellular localization, and bioinformatics analysis to identify key isoforms and metabolic branches associated with sucrose biosynthesis in wheat. Our analysis identified 45 genes from 13 families that exhibited high expression in young leaves with an evident diurnal change. The carbon flux from photoassimilates to sucrose was divided into two pathways. In the cytoplasm, assimilates initiating at phosphotrioses (TPs) exported by TaTPT1 from chloroplasts flowed along the TP-Sucrose branch formed by TaALD6, TaFBP5, TacPGI, TacPGM, TaUGP1, TaSPS5, and TaSPP1. Intermediates either from the Calvin cycle or TP-Sucrose branch were converted into ADPGlc to synthesize the simple starch, which was transiently degraded by a series of enzymes, including TaBAM4 and TaSEX4 in the chloroplast. Similar to the starch-biosynthesis branch in endosperms, the TP-Sucrose branch is the most prominent in leaves because each reaction can be catalyzed by at least one highly expressed isoform with expected cytosolic localization. The key isoforms and major branches highlighted in the wheat sucrose biosynthesis pathway expand our molecular understanding of crop sucrose biosynthesis and provide clues to increase wheat yield by enhancing the sucrose synthesis efficiency of leaves. • TaFBP catalyzes the dephosphorylation of Fru16BP in young wheat leaves. • Transitory starches in wheat leaves mainly produced by SSs and BEs. • TP-Sucrose is the predominant branch in wheat sucrose biosynthesis pathway. • Forty-five genes play important roles in wheat sucrose biosynthesis. [ABSTRACT FROM AUTHOR]

Cobalt recovery from aqueous Co(II) is one critical step for recovery of cobalt and recycle of spent lithium ion batteries, but suffers from consumption of large amount of energy and chemicals. Previous tests have primarily examined the performance of graphite felt cathode for Co(II) reduction and hydrogen production in microbial electrolysis cells (MECs). The materials of nickel foam (NF), stainless steel woven mesh (SSM), titanium sheet (TS), carbon cloth (CC), and nickel foam + graphene (NF + G) were compared here as cathodes for Co(II) reduction and hydrogen evolution in MECs. Co(II) reduction on the cathodes of TS, SSM, CC and NF + G was not significantly different from each other and increased with the increase of applied voltage from 31.8 ± 6.0% at 0.2 V to 72.2 ± 4.6% at 0.5 V, which was always higher than 16.5 ± 1.8%‒53.4 ± 2.2% on the NF cathodes at the same range of applied voltage. While a low dissolved oxygen (DO) of 1.0 mg/L benefited to both Co(II) reduction and hydrogen evolution for all the materials cathodes with generally appreciable differences from each other, cobalt produced in previous fed-batch operations improved hydrogen evolution in the subsequent batch cycles. These results provide the first assessment of these materials for Co(II) reduction with simultaneous hydrogen evolution, and SSM as the most promising inexpensive alternative to the others. [ABSTRACT FROM AUTHOR]