Improvement of inflammatory bowel disease by lactic acid bacteria-derived metabolites: a review.

Lactic acid bacteria (LAB) plays a crucial role in the establishment and maintenance of host health, as well as the improvement of some diseases. One of the major modes is the secretion of metabolites that may be intermediate or end products of the LAB's metabolism. In this review, we summarized some common metabolites (particularly short-chain fatty acids [SCFAs], bacteriocin, and exopolysaccharide [EPS]) from LAB in fermented foods and the gut for the first time. The effects of LAB-derived metabolites (LABM) on inflammation, oxidative stress, the intestinal barrier, and gut microbiota in inflammatory bowel disease (IBD) model are also discussed. The discovery of LABM and identification of IBD biomarkers are mainly attributed to the development of metabolomics technologies, especially nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography tandem mass spectrometry (LC-MS). The application of these metabolomics technologies in identification of LABM and IBD biomarkers are also summarized and analyzed. Although the beneficial effects of some LABM have been explored, undiscovered metabolites and their functions still need further investigations.

Recent advance in quality preservation of non-thermal preservation technology of fresh mushroom: a review.

Fresh mushrooms have a long history of cultivation and consumption, but high postharvest losses are a concern in the commercial production of mushrooms worldwide. Thermal dehydration is widely used in the preservation of commercial mushrooms, but the flavor and taste of mushrooms are significantly altered after dehydration. Non-thermal preservation technology, which effectively maintains the characteristics of mushrooms, is a viable alternative to thermal dehydration. The objective of this review was to critically assess the factors affecting fresh mushroom quality after preservation is remarkable, with the ultimate goal of developing and promoting non-thermal preservation technology for preserving fresh mushroom quality, effectively extending the shelf life of fresh mushrooms. The factors influencing the quality degradation process of fresh mushrooms discussed herein include the internal factors associated with the mushroom itself and the external factors associated with the storage environment. We present a comprehensive discussion of the effects of different non-thermal preservation technologies on the quality and shelf life of fresh mushrooms. To prevent quality loss and extend the shelf life after postharvest, hybrid methods, such as physical or chemical techniques combined with chemical techniques, and novel nonthermal technologies are highly recommended.

Mitigation of Dextran-Sodium-Sulfate-Induced Colitis in Mice through Oral Administration of Microbiome-Derived Inosine and Its Underlying Mechanisms.

BACKGROUND: Colonic and serum inosine are significantly reduced in patients with inflammatory bowel disease (IBD). METHODS: This study aimed to explore whether microbiome-derived inosine alleviates colitis and its underlying mechanisms. RESULTS: An inosine intervention effectively improved the clinical signs in colitis mice, suppressed inflammatory cytokines (tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and IL-1ß) by regulating the nuclear factor-kappa B (NF-κB) pathway, and elevated the activities of anti-oxidative enzymes (including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px)) by regulating the nuclear factor erythroid-2 related factor 2 (Nrf2) pathway. Additionally, the inosine intervention significantly elevated the expression of tight junction proteins (ZO-1, occudin, and claudin-1) in mice with colitis. High-throughput sequencing revealed that the inosine intervention also prevented gut microbiota disorder by increasing the abundance of beneficial bacteria (Lachnospiraceae NK4A136 group, Romboutsia, Marvinbryantia, Clostridium sensu stricto 1, and Bifidobacterium) and reducing the abundance of harmful bacteria (Pseudomonas, Acinetobacter, and Tyzzerella) in mice with colitis. CONCLUSIONS: Inosine played a significant role in mitigating colitis-related intestinal barrier injury and could potentially be used for therapy in clinical practice.

Broccoli seed extract rich in polysaccharides and glucoraphanin ameliorates DSS-induced colitis via intestinal barrier protection and gut microbiota modulation in mice.

BACKGROUND: Broccoli has received widespread attention because of its anti-inflammatory and antioxidant effects. The present study aimed to explore the composition of broccoli seed extract (BSE) and its effect on colitis induced by dextran sulfate sodium (DSS). RESULTS: BSE mainly comprises glucoraphanin and polysaccharides composed of arabinose, galactose, glucose and mannose. Animal experiments suggested that BSE intervention effectively reversed body weight loss, suppressed the levels of proinflammatory interleukin-6, tumor necrosis factor-α and interleukin-1ß, and elevated the levels of anti-inflammatory interleukin-10 and the activities of superoxide dismutase and glutathione in DSS-induced colitis mice. According to histopathologic and immunohistochemical analysis of colon tissue, BSE intervention may repair the intestinal barrier by upregulating mRNA levels and the expression of tight junction proteins (claudin-1, occludin and zonula occludens-1). Gas chromatography-mass spectrometry (MS) analysis demonstrated that cecal short-chain fatty acids in mice with BSE administration were significantly increased compared with the model group. Sulforaphane and sulforaphane-N-acetylcysteine were only detected in BSE group mice by ultra-performance liquid chromatography-MS analysis. In addition, BSE intervention evidently increased the abundance of Alistipeds, Coriobacteriaceae UCG-002 and Bifidobacterium and decreased the abundance of Escheichia-Shinella, Lachnospiraceae others, Parabacteroides, Ruminococcaceae others and Turicibacter, which possibly promoted carbohydrate metabolism and short-chain fatty acid production. CONCLUSION: The present study aimed to elucidate the effect of BSE on colitis and found that BSE, as a novel food ingredient, has great potential for the improvement of colitis. © 2022 Society of Chemical Industry.

Intestinal microbiomics and hepatic metabolomics insights into the potential mechanisms of probiotic Bifidobacterium pseudolongum CCFM1253 preventing acute liver injury in mice.

BACKGROUND: Bifidobacterium pseudolongum is widely exists in mammal gut and its abundance is associated with human and animal health. The present study aimed to investigate the potential mechanisms of B. pseudolongum CCFM1253 on protecting against lipopolysaccharide (LPS)-induced acute liver injury (ALI) by metagenomic analysis and liver metabolomic profiles. RESULTS: Bifidobacterium pseudolongum CCFM1253 preintervention remarkably attenuated the influence of LPS on serum alanine transaminase and aspartate amino transferase activities. B. pseudolongum CCFM1253 preintervention remarkably attenuated the inflammation responses (tumor necrosis factor-α, interleukin-1ß, and interleukin-6) and elevated antioxidative enzymes activities [total antioxidant capacity, superoxide dismutase, catalase, and glutathione peroxidase] in ALI mice by intervening in the Nf-kß and Nrf2 pathways, respectively. Bifidobacterium pseudolongum CCFM1253 treatment elevated the proportion of Alistipes and Bifidobacterium, and decreased the proportion of uncultured Bacteroidales bacterium, Muribaculum, Parasutterella and Ruminococcaceae UCG-010 in ALI mice, which were strongly correlated with the inhibition of inflammation responses and oxidative stress. Untargeted liver metabolomics exhibited that the hepatoprotective efficacy of B. pseudolongum CCFM1253 might be achieved by altering liver metabolites-related riboflavin metabolism, phenylalanine metabolism, alanine, citrate cycle (tricarboxylic acid cycle), and so on. Furthermore, riboflavin exposure could control the contents of malondialdehyde, superoxide dismutase, and catalase in hydrogen peroxide-treated HepG2 cells. CONCLUSION: Bifidobacterium pseudolongum CCFM1253 can effectively alleviate inflammatory response and oxidative stress, and regulate the intestinal microbiota composition and liver metabolism, and elevate the liver riboflavin content in LPS-treated mice. Therefore, B. pseudolongum CCFM1253 could serves as a potential probiotic to ameliorate the host health. © 2023 Society of Chemical Industry.

Efficiency improvement of GaN-based micro-light-emitting diodes embedded with Ag NPs into a periodic arrangement of nano-hole channel structure by ultra close range localized surface plasmon coupling.

NH-µLED, namely a micro light-emitting diode structure with nano-holes dug all the way through the active region, is designed to make silver nanoparticles in extremely close contact with the quantum wells for improving the coupling between the localized surface plasmon and the quantum wells (LSP-QWs coupling) and thus enhancing the optical properties of theµLED. The experimental results show that, thanks to this deep nanohole structure, the LSP-QWs coupling can be realized effectively, which ultimately increases the optical performance of theµLED. The internal quantum efficiency of the NH-µLED filled with silver nanoparticles is increased by 12%, and the final optical output power is also enhanced. We have further carried out a comparison study which measures the transient lifetime of two different types ofµLEDs, and the results provide convincing evidence for the existence of the ultra close range LSP-QWs coupling effect.

A new approach to simultaneously reducing, nitrogen doping and noble metal coating of graphene oxide via active-screen plasma.

Graphene is widely used for various applications, especially after nitrogen doping and incorporation with metal nanoparticles. Herein, a simultaneous approach to reducing, nitrogen doping and noble metals coating of graphene oxide (GO) is reported using an advanced active-screen plasma (ASP) technique. With a noble metal plate added as an extra lid of active screen cage, the corresponding noble metal, mainly or fully in pure metal state, depending on the noble metal type, as well as a minority of Fe and Cr, is deposited on GO with simultaneous reduction and nitrogen doping. The ASP treated GO exhibits varying levels of improvement in electrical property depending on the type of noble metal nanoparticles hybridized with. Specifically, ASP treated GO incorporated with Pt or Au revealed 2-4 orders of magnitude of improvement in electrical property.

Issue of spatial coherence in MQW based micro-LED simulation.

In existing flip-chip LED simulations, the light extraction efficiency is related to the multiple quantum well (MQW) to metal reflector distance because of optical interference. We calculate the contrast using several typical light intensity distributions among the several QWs in MQW. The coherence is obtained analytically. When the luminosity of each QW is equal, the contrast is ∼0, meaning the light is incoherent, contrary to traditional studies. The spatial coherence is important only when the light emission comes from just one QW. As the MQW has a not negligible thickness, the traditional single-dipole model is no longer accurate.

Graphene-assisted preparation of large-scale single-crystal Ag(111) nanoparticle arrays for surface-enhanced Raman scattering.

Surface plasmon resonance (SPR) of metal nanostructures has broad application prospects in the fields of sensing, energy, catalysis and optics. This paper reports a graphene-assisted method for preparing large-scale single-crystal Ag(111) nanoparticle (NP) arrays based on the ion implantation technique. By surface periodic patterning treatment and annealing of the implanted sample, regularly arranged Ag NPs can be prepared on the sample surface. A new application for graphene is proposed, that is, as a perfect barrier layer to prevent metal atoms from evaporating or diffusing. All the Ag NPs show (111) crystal orientation. Besides, the Ag atoms are covered by graphene immediately when they precipitate from the substrate, which can prevent them from being oxidized. On the basis of this structure, as one of the applications of the metal SPR, we have measured the surface-enhanced Raman scattering effect and found that the G peak of the Raman spectrum of the graphene achieved about 20 times enhancement.

Transfer-free, lithography-free and fast growth of patterned CVD graphene directly on insulators by using sacrificial metal catalyst.

Chemical vapor deposited graphene suffers from two problems: transfer from metal catalysts to insulators, and photoresist induced degradation during patterning. Both result in macroscopic and microscopic damages such as holes, tears, doping, and contamination, translated into property and yield dropping. We attempt to solve the problems simultaneously. A nickel thin film is evaporated on SiO2 as a sacrificial catalyst, on which surface graphene is grown. A polymer (PMMA) support is spin-coated on the graphene. During the Ni wet etching process, the etchant can permeate the polymer, making the etching efficient. The PMMA/graphene layer is fixed on the substrate by controlling the surface morphology of Ni film during the graphene growth. After etching, the graphene naturally adheres to the insulating substrate. By using this method, transfer-free, lithography-free and fast growth of graphene realized. The whole experiment has good repeatability and controllability. Compared with graphene transfer between substrates, here, no mechanical manipulation is required, leading to minimal damage. Due to the presence of Ni, the graphene quality is intrinsically better than catalyst-free growth. The Ni thickness and growth temperature are controlled to limit the number of layers of graphene. The technology can be extended to grow other two-dimensional materials with other catalysts.

Exploring core functional microbiota responsible for the production of volatile flavour during the traditional brewing of Wuyi Hong Qu glutinous rice wine.

The objective of this study was to explore the core functional microbiota for the production of volatile flavour during the traditional brewing of Wuyi Hong Qu glutinous rice wine, one of the most typical representatives of rice wine in China. Microbiological analysis based on high-throughput sequencing (HTS) technology demonstrated that bacteria of Lactobacillus, Bacillus, Leuconostoc, Lactococcus, Raoultella, Staphylococcus, Pediococcus, and Weissella, and fungi of Saccharomyces, Saccharomycopsis, Rhizopus, Monascus, Pichia, Wickerhamomyces, Candida, and Aspergillus were the predominant genera during the traditional fermentation process. Principal component analysis (PCA) based on the relative abundance showed that both of bacterial and fungal communities varied significantly in different fermentation phases. Some predominant microbial species or genera (including bacteria of Bacillus spp., Staphylococcus spp., Weissella spp., and P. acidilactici, and fungi of M. purpureus, R. oryzae, R. arrhizus var. arrhizus, and A. niger) were detected at the initial brewing stage, and their populations decreased as the fermentation progressed, while those of Lactobacillus, Gluconacetobacter, Leuconostoc, Pichia, Wickerhamomyces, and Saccharomyces increased to become the predominant genera at the final stage. A total of 79 volatile compounds were identified in traditional fermentation starters and during the traditional brewing process, mainly including esters, alcohols, acids, aldehydes, ketones, and phenols. Heatmaps and PCA also revealed the significant variances in the composition of volatile compounds among different samples. Furthermore, the potential correlations between microbiota succession and volatile flavour dynamics were explored through bidirectional orthogonal partial least squares (O2PLS) based correlation analysis. Three bacterial genera, namely, Gluconacetobacter, Lactobacillus, Lactococcus, and three fungal genera of Pichia, Wickerhamomyces, and Saccharomyces, were determined as the core functional microbiota for production of main volatile compounds in Wuyi Hong Qu glutinous rice wine. To conclude, information provided by this study is valuable to the development of effective strategies for the selection of beneficial bacterial and fungal strains to improve the quality of Wuyi Hong Qu glutinous rice wine.

Construction and cellular uptake behavior of redox-sensitive docetaxel prodrug-loaded liposomes.

A redox-responsive docetaxel (DTX) prodrug consisting of a disulfide linkage between DTX and vitamin E (DTX-SS-VE) was synthesized in our laboratory and was successfully formulated into liposomes. The aim of this study was to optimize the formulation and investigate the cellular uptake of DTX prodrug-loaded liposomes (DPLs). The content of DTX-SS-VE was determined by ultrahigh-performance liquid chromatography (UPLC). The formulation and process were optimized using entrapment efficiency (EE), drug-loading (DL), particle size and polydispersity index (PDI) as the evaluation indices. The optimal formulation was as follows: drug/lipid ratio of 1:12, cholesterol/lipid ratio of 1:10, hydration temperature of 40 °C, sonication power and time of 400 W and 5 min. The EE, DL and particle size of the optimized DPLs were 97.60 ± 0.03%, 7.09 ± 0.22% and 93.06 ± 0.72 nm, respectively. DPLs had good dilution stability under the physiological conditions over 24 h. In addition, DPLs were found to enter tumor cells via different pathways and released DTX from the prodrug to induce apoptosis. Taken together, the optimized formulation and process were found to be a simple, stable and applicable method for the preparation of DPLs that could successfully escape from lysosomes.

[Effect of Junction Temperature on EL Spectra of GaN-Based White High Voltage LEDs].

High voltage light emitting diodes (HV-LEDs) have potential advantages on general lighting application for their special features. But as novel power LEDs, their optical, electrical and thermal characteristics still need to be further studied. In this paper, 6 and 9 V GaN-based HV-LEDs were packaged in the same package structure and process conditions. The optical characteristics of two samples were investigated under different temperatures range from 10 to 70 ℃ which were calibrated to junction temperatures using thermal impedance measurement. To ensure the same current density, working current was set to 150 mA for 6 V sample and 100 mA for 9 V sample respectively. Results show that the increasing junction temperature has a great effect on EL spectra of two samples, such as peak wavelength red-shifting, full width at half maximum (FWHM) broadening, luminous efficiency reducing and color rendering index (CRI) increasing. The junction temperature of 9V sample is lower than that of 6 V sample in the same platform temperature and injection power. With temperature increasing, the extended quantitative value of FWHM for 9 V sample is 1.3 nm less than that of 6 V sample, the reduced quantitative value of luminous efficiency is 1.13 lm·W(-1) less than that of 6 V sample, while the increased quantitative value of CRI is 0.28 less than that of 6 V sample. Those data suggest that EL spectra of HV-LEDs is less affected by junction temperature than traditional LEDs. It is because HV-LEDs perform better in current spreading and generate less heat. This conclusion has reference value for study, development and applications of GaN-based HV-LEDs. In addition, peak wavelength still has a good linear relationship with junction temperature and it can be a temperature-sensitive parameter when the spectra measurement accuracy is enough.

Genome-wide identification, classification, and analysis of NADP-ME family members from 12 crucifer species.

NADP-dependent malic enzymes (NADP-MEs) play essential roles in both normal development and stress responses in plants. Here, genome-wide analysis was performed to identify 65 putative NADP-ME genes from 12 crucifer species. These NADP-ME genes were grouped into five categories of syntenic orthologous genes and were divided into three clades of a phylogenic tree. Promoter motif analysis showed that NADP-ME1 genes in Group IV were more conserved with each other than the other NADP-ME genes in Groups I and II. A nucleotide motif involved in ABA responses, desiccation and seed development was found in the promoters of most NADP-ME1 genes. Generally, the NADP-ME genes of Brassica rapa, B. oleracea and B. napus had less introns than their corresponding Arabidopsis orthologs. In these three Brassica species, the NADP-ME genes derived from the least fractionated subgenome have lost less introns than those from the medium fractionated and most fractionated subgenomes. BrNADP-ME1 showed the highest expression in petals and mature embryos. Two paralogous NADP-ME2 genes (BrNADP-ME2a and BrNADP-ME2b) shared similar expression profiles and differential expression levels. BrNADP-ME3 showed down-regulation during embryogenesis and reached its lowest expression in early cotyledonary embryos. BrNADP-ME4 was expressed widely in multiple organs and showed high expression during the whole embryogenesis process. Different NADP-ME genes of B. rapa showed differential gene expression profiles in young leaves after ABA treatment or cold stress. Our genome-wide identification and characterization of NADP-ME genes extend our understanding of the evolution or function of this family in Brassicaceae.

Redox-Sensitive Citronellol-Cabazitaxel Conjugate: Maintained in Vitro Cytotoxicity and Self-Assembled as Multifunctional Nanomedicine.

Citronellol-cabazitaxel (CIT-ss-CTX) conjugate self-assembled nanoparticles (CSNPs) were designed and prepared by conjugating cabazitaxel with citronellol via the disulfide bond that is redox-sensitive to the high concentration of glutathione within tumor cells. Notably, the CSNPs maintained in the cell cytotoxicity. Moreover, the AUC0-t of CSNPs was 6.5-fold higher than that of cabazitaxel solutions and the t1/2 was prolonged 2.3 times. Furthermore, we found that CSNPs could be employed as an efficient carrier for other hydrophobic drugs or imaging agents. Thus, the in vivo targeting study was implemented via using 1,1-dioctadecyl-3,3,3,3-tetramethylindotricarbocyanine iodide (DiR)-loaded CSNPs as imaging agent, which showed CSNPs could effectively accumulate at the tumor site. Curcumin, a hydrophobic anticancer drug, was successfully loaded in CSNPs which exhibits good stability and synergistic antitumor effects. The citronellol-cabazitaxel conjugate therefore has a promising perspective as a multifunctional nanomedicine for combination therapy and theranostics attributed to its long-circulation property, redox-sensitive mechanism, and high drug coloading capability.

Mechanism of Electrochemical Delamination of Two-Dimensional Materials from Their Native Substrates by Bubbling.

A capacitor-based circuit model is proposed to explain the electrochemical delamination of two-dimensional materials from their native substrates where produced gas bubbles squeeze into the interface. The delamination is actually the electric breakdown of the capacitor formed between the solution and substrate. To facilitate the procedure, the backside of the ubstrate has to be shielded so that the capacitor breakdown voltage can be reached. The screening effect can be induced either by nonreactive ions around the electrode or, more effectively, by an undetachable insulator. This mechanism serves as a guideline for the surface science and applications involving the bubbling delamination.

Genome-wide identification and characterization of aquaporin genes (AQPs) in Chinese cabbage (Brassica rapa ssp. pekinensis).

Aquaporins (AQPs) are members of a superfamily of integral membrane proteins and play a significant role in the transportation of small molecules across membranes. However, currently little is known about the AQP genes in Chinese cabbage (Brassica rapa ssp. pekinensis). In this study, a genome-wide analysis was carried out to identify the AQP genes in Chinese cabbage. In total, 53 non-redundant AQP genes were identified that were located on all of the 10 chromosomes. The number of AQP genes in Chinese cabbage was greater than in Arabidopsis. They were classified into four subfamilies, including PIP, TIP, NIP, and SIP. Thirty-three groups of AQP orthologous genes were identified between Chinese cabbage and Arabidopsis, but orthologs corresponding to AtNIP1;1 and AtPIP2;8 were not detected. Seventeen groups of paralogous genes were identified in Chinese cabbage. Three-dimensional models of the AQPs of Chinese cabbage were constructed using Phyre2, and ar/R selectivity filters were analyzed comparatively between Chinese cabbage and Arabidopsis. Generally, gene structure was conserved within each subfamily, especially in the SIP subfamily. Intron loss events have occurred during the evolution of the PIP, TIP, and NIP subfamilies. The expression of AQP genes in Chinese cabbage was analyzed in different organs. Most AQP genes were downregulated in response to salt stress. This work shows that the AQP genes of Chinese cabbage have undergone triplication and subsequent biased gene loss.

Synthesis of Ganoderic Acids Loaded Zein-Chitosan Nanoparticles and Evaluation of Their Hepatoprotective Effect on Mice Given Excessive Alcohol.

Ganoderma lucidum, used in East Asia for its health benefits, contains ganoderic acids (GA) which have various pharmacological activities but are limited by poor water solubility and low oral bioaccessibility. This study synthesized and characterized ganoderic acids loaded zein-chitosan nanoparticles (GA-NPs), and investigated its advantages in alleviating alcoholic liver injury (ALI) in mice model. The GA-NPs demonstrated high encapsulation efficiency (92.68%), small particle size (177.20 nm), and a +29.53 mV zeta potential. The experimental results of alcohol-induced liver injury mouse model showed that GA-NPs significantly improved liver metabolic function, reduced alcohol-induced liver oxidative stress in liver by decreasing lactate dehydrogenase activity and malondialdehyde level, while increasing the activities of liver antioxidant enzymes and alcohol dehydrogenase. Moreover, GA-NPs were favorable to ameliorate intestinal microbiota dysbiosis in mice exposed to alcohol by increasing the proportion of probiotics such as Romboutsia, Faecalibaculum, Bifidobacterium and Turicibacter, etc., which were highly correlated with the improvement of liver function. Furthermore, GA-NPs modulated the mRNA expression related to ethanol metabolism, oxidative stress and lipid metabolism. Conclusively, this study revealed that GA-NPs have stronger hepatoprotective effects than non-encapsulated ganoderic acids on alleviating ALI by regulating intestinal microbiota and liver metabolism.

Advancements in Micro-LED Performance through Nanomaterials and Nanostructures: A Review.

Micro-light-emitting diodes (µLEDs), with their advantages of high response speed, long lifespan, high brightness, and reliability, are widely regarded as the core of next-generation display technology. However, due to issues such as high manufacturing costs and low external quantum efficiency (EQE), µLEDs have not yet been truly commercialized. Additionally, the color conversion efficiency (CCE) of quantum dot (QD)-µLEDs is also a major obstacle to its practical application in the display industry. In this review, we systematically summarize the recent applications of nanomaterials and nanostructures in µLEDs and discuss the practical effects of these methods on enhancing the luminous efficiency of µLEDs and the color conversion efficiency of QD-µLEDs. Finally, the challenges and future prospects for the commercialization of µLEDs are proposed.

The food security risks in the Yangtze River Delta of China associated with water scarcity, grain production, and grain trade.

Grain production consumes a large amount of water and is affected by the degree of water scarcity and participation in the grain trade in various regions. The grain trade has changed the food security risks in regions where grain exports and imports. Therefore, it is crucial to consider regional water scarcity to understand food security risks from the grain trade network. Here, we construct a new framework for measuring regional food security risks associated with water scarcity, grain production, and grain trade based on a cross-city grain trade network combined with virtual water flows to evaluate the regional food security risks in the Yangtze River Delta region (YRD) of China in 2017. The results show that under the current domestic grain trade pattern in China, the YRD and its four provincial-level administrative regions are in a net grain import state. The grain trade within the YRD is concentrated in exports from the two major grain-producing areas of Anhui and Jiangsu to Zhejiang and Shanghai, especially from northern Jiangsu to southeastern Zhejiang. The net import results of virtual blue water in most cities indicate that the YRD has shifted its water resource pressure to other grain exporting regions in China, with Shanghai and Zhejiang being the greatest beneficiaries. Extreme risk only exists in Shanghai, and severe and moderate risks are concentrated in Jiangsu. The current grain trade has reduced the overall food security risk in the YRD by 1.3 % but increased the risks in Shanghai and Zhejiang by 2.1 % and 0.8 % respectively. This study highlights the potential risks that excessive production of food in water-scarce areas in the grain trade system may bring to a stable food supply, providing useful information for a comprehensive understanding of the food and water security situation and for future trade-offs.