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Freshness is an important parameter of fish quality. This study aims to develop a ratiometric fluorescent sensing label that is responsive to volatile amines, affording real-time and visual detection of fish freshness. For developing of the sensing label, an aggregation-induced emissive (AIE) polymer was prepared from the stimuli-responsive polymer polymethacrylic acid and the AIE molecule tetraphenylethylene and coated on to filter paper with rhodamine B as an internal reference. By exploiting the ratiometric response, the freshness of fish could be identified clearly and easily according to the color of on-package label, which changes from pink (fresh) to dark blue. The difference was linearly correlated with the total volatile basic nitrogen (TVB-N, R

The reduction of the salt content of foods is of interest for health reasons. The present study showed that low-salt surimi gels could be produced using a combination of l-arginine (Arg) and transglutaminase (TGase) under microwave (MW) irradiation. The low-salt surimi gels produced by MW had similar physicochemical properties as regular-salt surimi gels produced by conventional two-stage water bath heating. Compared to low-salt surimi gels containing TGase alone, Arg increased the water holding capacity and gel strength (P 0.05) and promoted the formation of a more homogeneous and compact three-dimensional gel network. As a result, there was a significant increase in the proportion of immobilized water and decrease in the proportion of free water (P 0.05). The nature of the binding sites between Arg and myosin heavy chain was predicted using the molecular docking simulations analysis. These results may be useful for the development of low-salt surimi products.

In this study, the stability and flavor characteristics of nanoemulsions prepared with dextran-conjugated Meretrix meretrix clam protein isolate were studied by characterizing particle size, polydispersity index, zeta potential, turbidity, microstructure, e-tongue, e-nose and HS-GC-IMS. Compared with the NCPI (CPI nanoemulsions) and NCPI-Dex Mix (CPI-Dex Mix nanoemulsions), the NCPI-Dex Con (CPI-Dex Con nanoemulsions) has better stability and flavor. The breaking strength and breaking strain of clam sausages were significantly (P > 0.05) affected by the addition of NCPI-Dex Con. The gel strength with 8% NCPI-Dex Con was the highest (5122.08 g‧mm), a 51.07% increase compared with the control group (3390.58 g‧mm). The clam sausages supplemented with the 8% NCPI-Dex Con had the highest sensory score, with the densest and the most uniform gel structure. Therefore, CPI-Dex Con stabilized nanoemulsions could effectively improve the gel property and flavor of the clam sausages.

Significance We report that suppression of the serine protease elastase reshapes innate responses induced by injected vaccines containing alum adjuvant. This reprogramming improves the induction of protective antibodies in the bloodstream and stimulates innate signals, which support the development of antibody responses in mucosal tissues. Our findings identify elastase as the innate regulator that blunts the adjuvant activity of alum. They also demonstrate that vaccination via mucosal routes is not an absolute requirement for antibody responses in mucosal tissues and secretions. Supplementation of an alum-based vaccine containing SARS-CoV-2 spike protein subunit 1 as antigen increased anti–SARS-CoV-2 immunity in the blood and mucosal secretions in mice. Thus, this strategy could help in the development of future protein-based vaccines against SARS-CoV-2., Alum, used as an adjuvant in injected vaccines, promotes T helper 2 (Th2) and serum antibody (Ab) responses. However, it fails to induce secretory immunoglobulin (Ig) A (SIgA) in mucosal tissues and is poor in inducing Th1 and cell-mediated immunity. Alum stimulates interleukin 1 (IL-1) and the recruitment of myeloid cells, including neutrophils. We investigated whether neutrophil elastase regulates the adjuvanticity of alum, and whether a strategy targeting neutrophil elastase could improve responses to injected vaccines. Mice coadministered a pharmacological inhibitor of elastase, or lacking elastase, developed high-affinity serum IgG and IgA antibodies after immunization with alum-adsorbed protein vaccines, including the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). These mice also developed broader antigen-specific CD4+ T cell responses, including high Th1 and T follicular helper (Tfh) responses. Interestingly, in the absence of elastase activity, mucosal SIgA responses were induced after systemic immunization with alum as adjuvant. Importantly, lack or suppression of elastase activity enhanced the magnitude of anti–SARS-CoV-2 spike subunit 1 (S1) antibodies, and these antibodies reacted with the same epitopes of spike 1 protein as sera from COVID-19 patients. Therefore, suppression of neutrophil elastase could represent an attractive strategy for improving the efficacy of alum-based injected vaccines for the induction of broad immunity, including mucosal immunity.

Bacteria are the main cause of spoilage for fish and fishery products. Through the inactivation of the quorum sensing (QS) system, quorum quenching (QQ) enzymes can block the synthesis of bacterial virulence factors and effectively inhibit bacteria-induced food spoilage. This study analyzed the changes of microbiota in red sea bream filets during refrigerated storage. The results showed a decrease in microbial diversity with storage time, with Aeromonas veronii becoming the dominant bacteria on day 4. A novel N-acyl homoserine lactones (AHL) acylase PF2571, from the screened QQ bacterium Pseudomonas fluorescens PF08, was identified and expressed in Escherichia coli to evaluate its QQ efficiency and effects on spoilage potential. Spoilage-related QS factors of A. veronii BY-8, including biofilm formation, motility, and protease, lipase, and alginate production, were inhibited by PF2571. Its inhibitory effect on red sea bream spoilage was demonstrated by the lower freshness indicators for PF2571 treated filets. Our study demonstrates the potential of the QQ enzyme for prolonging the shelf life of fish and fishery products.

Among over 150 distinct RNA modifications, N6-methyladenosine (m6A) and adenosine-to-inosine (A-to-I) RNA editing represent 2 of the most studied modifications on mammalian mRNAs. Although both modifications occur on adenosine residues, knowledge on potential functional crosstalk between these 2 modifications is still limited. Here, we show that the m6A modification promotes expression levels of the ADAR1, which encodes an A-to-I RNA editing enzyme, in response to interferon (IFN) stimulation. We reveal that YTH N6-methyladenosine RNA binding protein 1 (YTHDF1) mediates up-regulation of ADAR1; YTHDF1 is a reader protein that can preferentially bind m6A-modified transcripts and promote translation. Knockdown of YTHDF1 reduces the overall levels of IFN-induced A-to-I RNA editing, which consequently activates dsRNA-sensing pathway and increases expression of various IFN-stimulated genes. Physiologically, YTHDF1 deficiency inhibits virus replication in cells through regulating IFN responses. The A-to-I RNA editing activity of ADAR1 plays important roles in the YTHDF1-dependent IFN responses. Therefore, we uncover that m6A and YTHDF1 affect innate immune responses through modulating the ADAR1-mediated A-to-I RNA editing., A study of the epitranscriptomic landscape reveals a functional role of the RNA modification N6-methyladenosine in suppressing aberrant innate antiviral immune responses by modulating A-to-I RNA editing and RNA secondary structure.

To fill the knowledge gap on how effective free chlorine is against viral-contaminated produce, we inoculated the surfaces of outdoor- or greenhouse-grown kale and mustard with Rotavirus (RV) or a human norovirus surrogate (Tulane virus, TV) and then disinfected the leaves with free chlorine. Disinfection efficacies for RV strain OSU and Wa were approximately 1-log10 higher when attached to mustard than to kale. Similar disinfection efficacies were observed for TV attached to mustard or kale. When examining TV and RV OSU in suspension (not attached to leaf surfaces), TV was more resistant to free chlorine than RV OSU. Inactivation efficacies were higher for these viruses in suspension versus viruses attached to produce the surface. We also found that free chlorine damaged viral capsids, allowing free chlorine access to viral RNA to damage viral genomes. Exposure to free chlorine at 1.7 ppm over 1 min caused VP8* of RV OSU to lose its ability to bind to its host receptors. TV lost its ability to bind to its receptor only after exposure to free chlorine at 29 ppm over 1 min. Thus, to reduce foodborne viral infections, it is important to consider the differences in virus' reactivity and inactivation mechanisms with free chlorine.

The present study investigated the volatile compounds in nearly three-year shrimp sauces and the effects of different fermentation and storage time on the integral aroma characteristics. The 89 volatile compounds were identified by solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) analysis. Compared with the other two samples, the shrimp sauces which fermented and storage for 2 years has the highest umami amino acid content and the better flavor. The results of electronic nose (e-nose) and electronic tongue (e-tongue) detection to distinguish the aroma characteristics of different samples demonstrated good agreement with those obtained by GC-MS analysis. These results suggested that proper fermentation and storage time are critical to the flavor quality of shrimp sauces.

Blueberry fruits were immersed in 100 mg/L acibenzolar-S-methyl (ASM) for 10 min and then stored at 4 °C with 40–50% relative humidity (RH) to investigate the changes of anti-oxidative enzyme activity, antioxidants and secondary metabolites in reactive oxygen species metabolism and phenylpropanoid pathway. The results indicated that ASM effectively enhanced the activity of superoxide dismutase, ascorbate peroxidase, catalase and the content of reduced glutathione and ascorbic acid in blueberries but decreased the content of H2O2. The activity of phenylalanine ammonialyase, polyphenol oxidase and the content of lignin, flavonoids, total phenolics and anthocyanin in blueberries were also enhanced by ASM treatment. These results suggest that postharvest ASM treatment could maintain the reactive oxygen species balance and enhance phenylpropanoid pathway to keep antioxidant ability of blueberries during low temperature storage.

The study investigated the effect of native cassava starch (NCS), hydroxypropylated starch, acetic acid esterification starch (AAES), acetylated distarch phosphate on gel properties and protein conformation of Nemipterus virgatus surimi. Addition of 10 g kg-1 NCS or 20 g kg-1 AAES could significantly promote the gel strength and textural profiles of the surimi gels (p < .05). The water holding ability and whiteness of surimi were remarkably increased when the four types of starch were added at all concentrations (p < .05). In rheological test, the lower G' was observed in surimi samples added with starch at low temperature, suggesting starch played an inactive filler role in surimi. Along with the increase of starch additive amount, ionic bond and hydrophobic interaction first increased and then decreased, while hydrogen bond first decrease and then increased. According to Raman spectroscopy data, small content of starch promoted the heat-induced conformational transition of surimi protein from α-helix to β-sheet, leading to the change in gel properties of surimi gels. Scanning electron microscopy photographs showed surimi gels added with 20 g kg-1 starch had the finer and denser network structure. Therefore, 20 g kg-1 AAES or 10 g kg-1 NCS or 10 g kg-1 HS could be proposed to a potential modifier to effectively improve the quality of surimi products.

The increasing demand for high-quality biogas and the reduction of reliance on natural gas have driven the need for a well-defined framework to ensure conformity and quality of biogas by the introduction of traceable reference materials and methods across the community. Furthermore, there is a great need to quantify critical trace impurities in biogas. Here, we perform real-time measurements on reference gas standards containing trace hydrocarbons in biogas that are traceable to the international system of units using Selected Ion Flow Tube Mass Spectrometry (SIFT-MS). There are limited data on reaction rate constants in biogas matrices for SIFT-MS, and here we use the traceable gas standards to determine and compare the reaction rate constants of trace hydrocarbons in biogas and nitrogen. Here, we modify SIFT-MS constants for biogas avoiding the current 30 % bias and prevent the overestimation in the concentration of hydrocarbon amount fractions.

The quorum sensing (QS) system enables bacteria, such as Pseudomonas fluorescens, which are vital psychrotrophic food spoilage bacteria, to control various physiological processes. Hence, targeting the bacterial QS might be a good method to control food spoilage and improve food quality. In this study, we screened the ZINC natural product database to search for potential QS inhibitors (QSIs) of P. fluorescens P07 using receptor-based pharmacophore model and virtual screening methods. A total of 28 compounds with high docking scores were tested for their anti-QS activities. The results showed that 22 compounds possessed anti-QS activities and the hit rate was very high (78.57%). Among them, guaiacol, citral et al. showed potent anti-QS activities. Moreover, the effects of guaiacol and citral on the QS-regulated phenotypes were determined. The results showed that guaiacol and citral significantly inhibited the swimming motility, production of extracellular enzymes, and siderophores of P. fluorescens P07. The inhibitory mechanism on the bacterial QS system was investigated by molecular docking analysis.

The influence of ultrasonics combined with microwave thawing (UMT) and ultrasonics combined with far-infrared thawing (UIT) on the water migration and protein denaturation of red drum were studied. Five treatments were used: ultrasonics thawing (UT), microwave thawing (MT), far-infrared thawing (IT), UIT and UMT were used for thawing red drum filets. Moisture migration and protein aggregation were studied using nuclear magnetic resonance (NMR) and particle size, respectively. Raman spectra and fluorescence spectra were used to study the secondary and tertiary structure of protein. SEM was done to observe the fiber microstructure. The results showed that UMT and UIT can maintained protein stability more than other thawing methods and retained the fiber structure of the muscle. Besides, immobilized water in fiber bundles network also had no significant changes compared with fresh samples. Thus, ultrasonics combined with far infrared or microwave thawing were used to decrease protein denaturation and water migration during the thawing of Red drum fillets.

Aims Pseudomonas fluorescens are important psychrotrophic food spoilage bacteria that are frequently detected in dairy, meat and aquatic products. Quorum sensing (QS) is an intercellular communication and gene regulation mechanism that enables bacteria to monitor their cell densities and regulate a variety of physiological processes. Hence, targeting the bacterial QS system might be a feasible approach to improve food quality and safety by regulating the spoilage caused by P. fluorescens. Methods and results In this study, we screened a food-derived three-dimensional (3D) compound database to search for potential QS inhibitors (QSIs) with higher security. The 3D structures of LuxI- and LuxR-type proteins of P. fluorescens P07 were used as targets to screen for QSIs. A total of 25 compounds with high docking scores were tested for their anti-QS activities by indicator strains. The results show that 19 compounds possessed anti-QS activities. Among them, (+)-catechin had the strongest anti-QS activity. The results show that (+)-catechin significantly inhibited the production of extracellular enzymes, swimming motility, biofilm formation, acyl-homoserine lactones and extracellular polymeric substances (EPSs) of P. fluorescens P07. The inhibitory mechanism of (+)-catechin on the QS system of P. fluorescens P07 was discussed in the context of molecular docking analysis and real-time quantitative PCR (RT-qPCR). Conclusions Virtual screening was useful in finding novel QSIs with high security of P. fluorescens P07 from a food-derived 3D compound database. The high hit rate suggested that foods are rich sources of QSIs, and have great potential for exploration. Significance and impact of the study The modelled LuxI- and LuxR-type proteins could be used as targets to discover P. fluorescens P07 QSIs. (+)-catechin, (-)-epicatechin, propyl gallate, hesperidin and lycopene which were identified as potent QSIs, and may be applied in food preservation and biofilm elimination.

This study examined the changes of water state and gel characteristics of Hairtail surimi during thermal processing including two steps. The results showed that there were four content of water in Hairtail surimi gels. Water-holding capacity (WHC) and T23 relaxation time of water and gel strength increased from 47.01 to 78.97% and from 64.23 to 51.52 ms, respectively, and whiteness decreased from 63.87 to 55.22 during the entire thermal processing. Meanwhile, the texture properties including hardness, gumminess, and chewiness declined from 402.42 to 130.41 g, from 294.39 to103.70 g, and from 233.68 to 43.60 g, respectively, during the first step, and then increased markedly during the second step from 130.41 to 2,301.87 g, from 103.70 to 1,250.99 g, and from 43.60 to 978.51 g, respectively. Furthermore, the WHC and textural profile had positive correlation, and changes in protein secondary structure were interesting, with the α-helices decreasing significantly from 26.40 to 14.12%, while the β-sheet and the random coil structure increasing significantly from 36.28 to 44.03%, and from 10.89 to 14.31%, respectively, and β-turn structure increasing form 26.44 to 27.98% during the first step and then declining markedly during the second step, moreover β-sheet had a fine positive correlation with WHC hardness and chewiness. Overall, dense, porous and compact three-dimensional network gel structure gradually formed. In a word, during thermal processing. WHC of Hairtail surimi increased, and protein secondary structure of protein became orderly, and a fine, dense gel formed during thermal processing. Water is considered as the highest and most important chemical constituent in surimi products. During surimi gelation, water molecules exist as bulk water and motionally restricted water on the protein surface. In order to gain more insights into the surimi heating-induced gelation processing, and improve the surimi gel properties, and give same advice to manufacturing enterprise, this work was conducted to study the structural changes of protein and water state during surimi gelation processing and performed along with the monitoring of the texture, WHC and other physical characteristics of surimi gel, as well as the microstructure of surimi gel.

The aim of this study was to evaluate the effect of vanillin as a QS inhibitor at sub-minimal inhibitory concentrations (sub-MICs) against fish spoilage by Hafnia alvei. Biofilm formation, swimming and swarming activity, and production of acyl-homoserine lactones (AHLs) were measured. In addition, analysis of quorum sensing (QS)-related genes by real-time quantitative PCR (RT-qPCR) and molecular docking was performed to better understand the inhibitory mechanism of vanillin. The results indicated that sub-MICs of vanillin induced remarkable reduction in violacein production (59.0%) and biofilm formation (68.5%) along with decreased swimming ability, and reduced expression levels of halI and halR. Moreover, the results of molecular docking revealed that vanillin and C6-HSL could form 2 hydrogen bonds with the LuxR protein (HalR), suggesting a potential competitive tendency between them. Thus, our study provides a basic inhibition mechanism of vanillin and suggests its prospective application as a QS inhibitor.

Protein oxidation is considered as an important issue in food preservation process. In the present study, the potential influence of protein oxidation on water holding capacity and protein structure of jumbo squid (Dosidicus gigas) mantle was investigated. After the hydroxyl radical oxidation, it was found that the carbonyl, surface hydrophobicity and dityrosine content of myofibrillar protein significantly increased (P

Fish gelatin was extracted from the bone of Alaska pollock (Theragra chalcogramma) and yellowfin sole (Limanda aspera) using papain-aided process and the characteristic and functional prope...

The effects of postharvest trisodium phosphate (TSP) dipping (0.5 mg/mL) on the quality and mitochondrial energy metabolism of apple fruit (cv. Golden delicious) were studied. The results indicated that TSP treatment inhibited the respiration intensity, delayed the increase of weight loss, and inhibited the decrease of flesh firmness, ascorbic acid (AsA), titratable acid (TA) and soluble solids content (SSC) of apple fruit. The results also indicated that TSP treatment delayed the decline of the content of ATP, ADP and energy charge of apple fruit, and enhanced the activity of H+-ATPase, Ca2+-ATPase, succinate dehydrogenase and cytochrome C oxidase. These results suggested that TSP could maintain the quality of apple fruit by mediating respiration and mitochondrial energy metabolism.

Apple fruit were treated with 100 mg L−1 acibenzolar-S-methyl (ASM) and 100 μM dehydroepiandrosterone (DHEA) to investigate its effect on the lesion development inoculated with Penicillium expansum. Effects of ASM on the glucose-6-phosphate dehydrogenase (G6PDH) activity, nicotinamide ademine dinucleotidephosphate (NADPH) production, and reactive oxygen species (ROS) metabolism in apple fruit were also studied. The results indicated that ASM treatment decreased the lesion development of blue mold in apple fruit. ASM treatment enhanced the content of H2O2, the activities of NADPH oxidase (NOX), superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and peroxidase (POD) in apple fruit. ASM treatment increased the gene expression of SOD, APX, DHAR as well as ascorbic acid (AsA) and reduced glutathione (GSH) content whereas it inhibited MDHAR expressions. The result also indicated that ASM treatment significantly inhibited CAT activity in apple fruit. In addition, the higher activity of G6PDH and content of NADPH was observed in ASM-treated apple fruit. In contrast, lesion diameter in ASM + DHEA-treated apple fruit developed more quickly than the control fruit. Also, the accumulation of H2O2, NADPH, AsA and GSH were reduced by DHEA treatment while inhibiting the activities of NOX, SOD, POD, APX, GR, MDHAR and G6PDH. Gene expressions of SOD, APX and DHAR were also inhibited by DHEA treatment. These results suggest that G6PDH played a crucial role in ROS metabolism and NADPH production in apple fruit to enhance resistance against P. expansum.

Pseudomonas fluorescens bacteria can grow well in cold-storage conditions and cause food spoilage. Quorum sensing (QS) is a biological pathway existing in a large number of microorganisms, through which bacteria regulate several of their physiological activities. A number of substances have been identified as quorum sensing inhibitors (QSIs); they can interfere with the QS system and control bacterial spoilage characteristics and production of virulence factors. In our previous study, propyl gallate at sub-minimum inhibitory concentration levels showed a potent anti-QS activity. Thus, in this study, coaxial polylactic acid-propyl gallate electrospun fibers were fabricated and their physicochemical properties were characterized. Salmon slices were coated with these electrospun fibers and the effect of this coating on the salmon slices during chilled storage was evaluated. The results showed that the electrospun fibers had a small diameter and smooth surface with no beads or other defects. The thermal stability, tensile strength, and other properties of the fibers were suitable for refrigerated storage conditions. Without inhibiting the bacterial growth in the salmon slices, the QSI-containing electrospun fibers exerted a significant inhibitory effect on the production of total volatile base nitrogen and trimethylamine. Furthermore, the deterioration of muscle tissue in the salmon slices was significantly delayed during cold storage. Quantitative analysis indicated that the electrospun fibers had a significant inhibitory effect on the bacterial spoilage ability. The results suggested that the electrospun fibers loaded with QSIs might be an effective strategy to control food spoilage and enhance the quality of aquatic food products.

In this work, we presented a new tetraphenylethene-derived fluorescent probe TPE-M for Hg2+ detection in an aqueous solution. Probe TPE-M is molecularly dissolved in CH3OH/PBS (20 mM, pH = 7.4) (3 : 7, v/v) mixed solution and is almost non-emissive. Reaction of TPE-M with Hg2+ leads to release of an AIE-active precursor 4, and results in a significant fluorescence enhancement. The Hg2+ recognition process has some distinct advantages including rapid response, high selectivity and sensitivity, strong anti-interference ability, and a low detection limit (4.16 × 10−6 M). Moreover, the probe is applicable to detect Hg2+ in real food samples such as shrimp, crab and teas, suggesting the practical applicability of TPE-M.

Paleoproterozoic glacigenic diamictites have provided key evidence for the Great Oxidation Event (GOE) at ∼2.3 Ga associated with the widespread Huronian Glaciation Event (HGE). Here we report for the first time Paleoproterozoic glacigenic diamictite from the Sijizhuang Formation of the Hutuo Group in Wutai Shan, China formed during the late stage of HGE. The Sijizhuang Formation comprises diamictite, sandstone and siltstone-mudstone facies, conforming to a glaciomarine association. The diamictites show weak sorting and roundness, and carry a few striated and faceted boulders. Typical dropstones and associated structures are present in the sandstone and siltstone-mudstone facies. Diamictite facies, which characterizes the lower portion of the Sijizhuang Formation, displays an upward decrease, with a concomitant increase in the proportions of sandstone and siltstone-mudstone facies. The lithofacies associations of diamictite with sandstone and siltstone-mudstone indicate a frequently changing hydrodynamic environment. The petrochemical compositions of different lithofacies show that the clasts were multi-sourced and generated by limited weathering, in keeping with a cold climate. Available isotope age data constrain the glacigenic deposition of the Sijizhuang Formation to between 2.40 and 2.13 Ga, and most likely from 2.2 to 2.1 Ga. This estimate compares well with the 2.4–2.1 Ga age of the widespread HGE but the Sijizhuang diamictite appears to be younger than the last glacial unit (Gowganda Formation) in the type area of the HGE in Canada and suggests a locally protracted glacial event.

This study investigated the effects of salting pretreatment and microwave (MW) power on drying characteristics, water distribution and quality attributes of Pacific white shrimp (Litopenaeus vannamei). With increasing salt concentration (0–8%, w/v) and MW power (300–900 W), the drying time of shrimp was shortened by 15.15–28.57%, compared with the untreated samples. Regarding the quality of dried shrimp, increasing the salt concentration and MW power increased the hardness (from 13,073.6 to 24,556.5 g), while the springiness, color parameters and astaxanthin content showed an initial decrease but a later increase trend. Low field nuclear magnetic resonance (LF-NMR) demonstrated that the T2 curve of the pretreated samples moved toward the negative x-axis and the immobilized water content decreased with increasing salt concentration. E-nose showed that volatile components were different and could be obviously distinguished at different salt concentrations and MW powers. Raman spectroscopy illustrated that the protein secondary structure of dried shrimp was altered by salting pretreatment and drying conditions, and the lowest conversion degree of α-helix to β-sheet of dried shrimp was obtained at the salt concentration of 4% (w/v) and MW power of 500 W. By comprehensively considering the drying time and quality attributes, the combination of 4% (w/v) salt and 500 W MW power was concluded as the best drying conditions for shrimp using a microwave. The results could provide an innovative combination of salt pretreatment and MW drying with suitable processing conditions for producing high-quality dried shrimp.

The effects on the quality of frozen red sea bream which were pretreated by soaking in solutions containing trehalose, chitosan magnetic nanoparticles (CS@Fe3O4 nanoparticles), and glycerin or different concentration herring antifreeze proteins (AFPs) were investigated in this study. The DSC, dynamic rheology, shear force, and TPA were conducted to analyze the physical characteristics. Raman and intrinsic fluorescence spectra were used to measure the protein secondary and tertiary structures. So-ANS and zeta potential were carried out to explore the degree of protein aggregation. Low-field NMR was used to test the water migration, and light microscope was performed to observe the fiber microstructure. Results showed that prior to freezing, the pretreatment of red sea bream samples with soak solutions could minimize drip loss, preserve the meat tenderness and texture, and improve the fish fillet thermal stability and viscoelasticity, and the free water content was decreased while the immobilized water content was increased; the longitudinal and transverse fiber structures were clear and less destructive. Compared with the control, the protein secondary and tertiary structures of samples, among the tested soaking solutions, tended to stability, and the degree of protein oxidation and aggregation was decreased. Therefore, this methodology was proved to be an effective method to inhibit the ice crystal growth and modify ice crystal form in order to improve the quality of the final product, and these effects were amplified with the concentration of AFPs increasingly.

The environment of marine occupies about 95% biosphere of the world and it can be a critical source of bioactive compounds for humans to be explored. Special environment such as high salt, high pressure, low temperature, low nutrition and no light, etc. has made the production of bioactive substances different from terrestrial organisms. Natural ingredients secreted by marine-derived bacteria, fungi, actinomycetes, Cyanobacteria and other organisms have been separated as active pharmacophore. A number of evidences have demonstrated that bioactive ingredients isolated from marine organisms can be other means to discover novel medicines, since enormous natural compounds from marine environment were specified to be anticancer, antibacterial, antifungal, antitumor, cytotoxic, cytostatic, anti-inflammatory, antiviral agents, etc. Although considerable progress is being made within the field of chemical synthesis and engineering biosynthesis of bioactive compounds, marine environment still remains the richest and the most diverse sources for new drugs. This paper reviewed the natural compounds discovered recently from metabolites of marine organisms, which possess distinct chemical structures that may form the basis for the synthesis of new drugs to combat resistant pathogens of human life. With developing sciences and technologies, marine-derived bioactive compounds are still being found, showing the hope of solving the problems of human survival and sustainable development of resources and environment.

Background Forty-two percent of patients experience disease comorbidity, contributing substantially to mortality rates and increased healthcare costs. Yet, the possibility of underlying shared mechanisms for diseases remains not well established, and few studies have confirmed their molecular predictions with clinical datasets. Methods In this work, we integrated genome-wide association study (GWAS) associating diseases and single nucleotide polymorphisms (SNPs) with transcript regulatory activity from expression quantitative trait loci (eQTL). This allowed novel mechanistic insights for noncoding and intergenic regions. We then analyzed pairs of SNPs across diseases to identify shared molecular effectors robust to multiple test correction (False Discovery Rate FDReRNA 1.5, FDRcomorbidity

The composite chitosan coatings were prepared and characterized to evaluate their preservation properties for silver carp fish balls, and the microstructures and physicochemical properties of the coatings were improved by in situ nano silicon oxide (SiOx) and zinc oxide/titania (ZnO/TiO2 ) nano-particles (NPs). In the chitosan coatings, when the chitosan combines with NPs by chemical bonds, the crystal lattice is slightly changed due to the modification of NPs. The chitosan coatings modified by NPs showed few cracks, among which sodium hexametaphosphate (SHMP) modified ZnO/TiO2 /SiOx-chitosan (ZTS-CS) coating is proved to be the optimal one. The change of the freshness index and the texture of the fish balls are delayed by the coatings due to their gas permeability and antibacterial properties. The preservation properties of the chitosan coatings for Silver Carp fish balls are improved by in situ SiOx, and further improved by co-modification of ZnO/TiO2 NPs. Furthermore, the surface modification of ZnO/TiO2 NPs enhances the preservation properties of the chitosan coating. PRACTICAL APPLICATION: In our previous study, in situ SiOx was found to improve antibacterial and preservation properties of chitosan coating, leading to extending shelf time of Sciaenops ocellatus. In order to further improve properties of chitosan coatings, we added nontoxic edible nano materials to the in situ SiOx chitosan coatings. In situ SiOx modified by ZnO/TiO2 NPs were synthesized, measured, and characterized in this study, and were applied for the preservation of silver carp fish balls. It could serve as a potential preservation material due to the increasing mechanical preservation properties. Through the results, the ZnO/TiO2 /SiOx-chitosan (ZTS-CS) coatings have potential as application in the food industry to guarantee food quality and extend shelf life of products.

N(6)-Methyladenosine (m(6)A) is the most abundant internal RNA modification catalyzed by host RNA methyltransferases. As obligate intracellular parasites, many viruses acquire m(6)A methylation in their RNAs. However, the biological functions of viral m(6)A methylation are poorly understood. Here, we found that viral m(6)A methylation serves as a molecular marker for host innate immunity to discriminate self from nonself RNA and that this novel biological function of viral m(6)A methylation is universally conserved in several families in nonsegmented negative-sense (NNS) RNA viruses. Using m(6)A methyltransferase (METTL3) knockout cells, we produced m(6)A-deficient virion RNAs from the representative members of the families Pneumoviridae, Paramyxoviridae, and Rhabdoviridae and found that these m(6)A-deficient viral RNAs triggered significantly higher levels of type I interferon compared to the m(6)A-sufficient viral RNAs, in a RIG-I-dependent manner. Reconstitution of the RIG-I pathway revealed that m(6)A-deficient virion RNA induced higher expression of RIG-I, bound to RIG-I more efficiently, enhanced RIG-I ubiquitination, and facilitated RIG-I conformational rearrangement and oligomerization. Furthermore, the m(6)A binding protein YTHDF2 is essential for suppression of the type I interferon signaling pathway, including by virion RNA. Collectively, our results suggest that several families in NNS RNA viruses acquire m(6)A in viral RNA as a common strategy to evade host innate immunity. IMPORTANCE The nonsegmented negative-sense (NNS) RNA viruses share many common replication and gene expression strategies. There are no vaccines or antiviral drugs for many of these viruses. We found that representative members of the families Pneumoviridae, Paramyxoviridae, and Rhabdoviridae among the NNS RNA viruses acquire m(6)A methylation in their genome and antigenome as a means to escape recognition by host innate immunity via a RIG-I-dependent signaling pathway. Viral RNA lacking m(6)A methylation induces a significantly higher type I interferon response than m(6)A-sufficient viral RNA. In addition to uncovering m(6)A methylation as a common mechanism for many NNS RNA viruses to evade host innate immunity, this study discovered a novel strategy to enhance type I interferon responses, which may have important applications in vaccine development, as robust innate immunity will likely promote the subsequent adaptive immunity.

Seafood spoilage can be prevented by inhibiting the quorum sensing (QS) system between bacteria. However, membrane materials combining freshness indicators with QS inhibition features have rarely been reported. Therefore, in this study, pH-sensitive polylactic acid-naringin coaxial electrospun fibers capable of maintaining and monitoring freshness were prepared and investigated. Surface analysis revealed that the fiber membranes exhibited a smooth surface and an average diameter of 243 nm. FTIR spectroscopy analysis revealed characteristic absorption peaks at 3265 and 1124 cm−1, confirming the successful loading of naringin and bromocresol purple. Release behavior analysis verified the uninterrupted release of naringin within 192 h, which enabled the fibers to achieve a protease inhibitory activity rate of 35.94%. Furthermore, the coaxial fibers successfully inhibited the expression of rhlI, rhlR, aprA, and fliA in Pseudomonas fluorescens. The real-world applicability of the coaxial fibers was evaluated by the salmon spoilage assay, where a 4-d extension to the shelf life of the coated fillets was attained. Additionally, the color of the coaxial fibers changed with the deterioration of salmon quality and the ΔE value increased from 4.75 to 26.51. These results verify that the prepared fibers can effectively monitor the freshness of seafood products and improve their storage conditions.

Highlights • Potency of peptides target to Mpro and ACE2 were investigated by molecular docking. • Gly143 and Gln189 played key roles in the interactions of peptide E-M and Mpro. • The RBD of ACE2 was occupied by peptide E-M to inhibit the activity of SARS-CoV-2. • Peptide E-M may be the potent nutritional supplement for COVID-19 patients., The present study aimed to identify potential SARS-CoV-2 inhibitory peptides from tuna protein by virtual screening. The molecular docking was performed to elicit the interaction mechanism between targets (Mpro and ACE2) and peptides. As a result, a potential antiviral peptide EEAGGATAAQIEM (E-M) was identified. Molecular docking analysis revealed that E-M could interact with residues Thr190, Thr25, Thr26, Ala191, Leu50, Met165, Gln189, Glu166, His164, His41, Cys145, Gly143, and Asn119 of Mpro via 11 conventional hydrogen bonds, 9 carbon hydrogen bonds, and one alkyl interaction. The formation of hydrogen bonds between peptide E-M and the residues Gly143 and Gln189 of Mpro may play important roles in inhibiting the activity of Mpro. Besides, E-M could bind with the residues His34, Phe28, Thr27, Ala36, Asp355, Glu37, Gln24, Ser19, Tyr83, and Tyr41 of ACE2. Hydrogen bonds and electrostatic interactions may play vital roles in blocking the receptor ACE2 binding with SARS-CoV-2.

Significance Measles virus (MeV) vaccine is one of the safest and most efficient vaccines with a track record in children. Here, we generated a panel of rMeV-based vaccines with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S antigens inserted near 3′ of the MeV genome. The rMeV expressing a soluble stabilized, prefusion spike (preS) is much more potent in triggering SARS-CoV-2–specific neutralizing antibody than rMeV-based full-length S vaccine candidate. A single dose of rMeV-preS is sufficient to induce high levels of SARS-CoV-2 antibody in animals. Furthermore, rMeV-preS induces high levels of Th1-biased immunity. Hamsters immunized with rMeV-preS were completely protected against SARS-CoV-2 challenge. Our results demonstrate rMeV-preS is a safe and highly efficacious bivalent vaccine candidate for SARS-CoV-2 and MeV., The current pandemic of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) highlights an urgent need to develop a safe, efficacious, and durable vaccine. Using a measles virus (rMeV) vaccine strain as the backbone, we developed a series of recombinant attenuated vaccine candidates expressing various forms of the SARS-CoV-2 spike (S) protein and its receptor binding domain (RBD) and evaluated their efficacy in cotton rat, IFNAR−/−mice, IFNAR−/−-hCD46 mice, and golden Syrian hamsters. We found that rMeV expressing stabilized prefusion S protein (rMeV-preS) was more potent in inducing SARS-CoV-2–specific neutralizing antibodies than rMeV expressing full-length S protein (rMeV-S), while the rMeVs expressing different lengths of RBD (rMeV-RBD) were the least potent. Animals immunized with rMeV-preS produced higher levels of neutralizing antibody than found in convalescent sera from COVID-19 patients and a strong Th1-biased T cell response. The rMeV-preS also provided complete protection of hamsters from challenge with SARS-CoV-2, preventing replication in lungs and nasal turbinates, body weight loss, cytokine storm, and lung pathology. These data demonstrate that rMeV-preS is a safe and highly efficacious vaccine candidate, supporting its further development as a SARS-CoV-2 vaccine.

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract (LRT) infections, with increased severity in high-risk human populations, such as infants, the immunocompromised, and the elderly. Although the virus was identified more than 60 years ago, there is still no licensed vaccine available. Over the years, several vaccine delivery strategies have been evaluated. In this study, we developed two recombinant vesicular stomatitis virus (rVSV) vector-based vaccine candidates expressing the RSV-G (attachment) protein (rVSV-G) or F (fusion) protein (rVSV-F). All vectors were evaluated in the cotton rat animal model for their in vivo immunogenicity and protective efficacy against an RSV-A2 virus challenge. Intranasal (i.n.) delivery of rVSV-G and rVSV-F together completely protected the lower respiratory tract (lungs) at doses as low as 10(3) PFU. In contrast, doses greater than 10(6) PFU were required to protect the upper respiratory tract (URT) completely. Reimmunization of RSV-immune cotton rats was most effective with rVSV-F. In immunized animals, overall antibody responses were sufficient for protection, whereas CD4 and CD8 T cells were not necessary. A prime-boost immunization regimen increased both protection and neutralizing antibody titers. Overall, mucosally delivered rVSV-vector-based RSV vaccine candidates induce protective immunity and therefore represent a promising immunization regimen against RSV infection. IMPORTANCE Even after decades of intensive research efforts, a safe and efficacious RSV vaccine remains elusive. Expression of heterologous antigens from rVSV vectors has demonstrated several practical and safety advantages over other virus vector systems and live attenuated vaccines. In this study, we developed safe and efficacious vaccine candidates by expressing the two major immunogenic RSV surface proteins in rVSV vectors and delivering them mucosally in a prime-boost regimen. The main immune parameter responsible for protection was the antibody response. These vaccine candidates induced complete protection of both the upper and lower respiratory tracts.

International audience; Biomethane is a renewable energy gas with great potential to contribute to the diversification and greening of the natural gas supply. Ideally, biomethane can directly be injected into the natural gas grid system. For grid injection, specifications such as those in EN 16723-1 shall be met. One of the impurities to be monitored is hydrogen chloride (HCl). To assess conformity with the specification for HCl, accurate and reliable test methods are required. Here, we report the development of three novel test methods, based on a variety of laser absorption spectroscopy techniques (Direct absorption spectroscopy-DAS and wavelength modulation spectroscopy-WMS) and ion-exchange chromatography, for the measurement of HCl in biomethane. Gas mixtures of HCl in biomethane were used to demonstrate the performance of the spectroscopic systems in the nmol mol−1 to low μmol mol−1 ranges, achieving uncertainties in the 4% range, k = 2. For ion-exchange chromatography analysis, HCl was first collected on an alkali-impregnated quartz fiber filter. The analysis was performed according to ISO 21438-2 and validated using synthetic biomethane spiked with HCl. The relative expanded uncertainties for the ion exchange chromatography HCl measurements are in the 10–37% range, k = 2. The results presented for the 3 test methods demonstrate that the respective methods can be used for HCl conformity assessment in biomethane.