Screening of core microorganisms in healthy and diseased peaches and effect evaluation of biocontrol bacteria (Burkholderia sp.).

Biological antagonists serve as the most important green alternatives to chemical fungicides, a class of microorganism that inhibits the growth of pathogenic fungi to reduce fruit incidence. In this paper, healthy and diseased peach fruit was selected for amplicon sequencing of the epiphytic microbiota on their surface to obtain a comprehensive understanding. Community structure, diversity and LefSe analysis were performed to screen Acetobacter, Muribaculaceae and Burkholderia as the core bacteria, Mycosphaerella, Penicillium and Alternaria as the core fungi, they showed significant differences and were highly enriched. Two strains fungi (Penicillium K3 and N1) and one strain antagonistic bacteria (Burkholderia J2) were isolated. The in intro test results indicated the bacterial suspension, fermentation broth and volatile organic compounds of antagonistic bacteria J2 were able to significantly inhibit pathogen growth. In vivo experiments, peach was stored at 28 °C for 6 days after different treatments, and samples were taken every day. It was found that Burkholderia J2 enhanced peach resistance by increasing the activities of antioxidant-related enzymes such as SOD, POD, PAL, PPO, GR, MDHAR, and DHAR. The results improved that Burkholderia J2 has great biocontrol potential and could be used as a candidate strain for green control of blue mold.

Stilbenes: A new strategy for protecting light-sensitive foods, a review of their structure classification and singlet oxygen quenching mechanism.

Natural stilbenes have been studied extensively as a result of their complicated structures and diverse biological activities. Singlet oxygen (1O2), a kind of reactive oxygen species (ROS) has a strong destructive effect on food systems (especially for light-sensitive foods). Many cutting-edge scientific studies have found that some stilbenes not only have extensive quenching properties for ROS, but also can selectively quench 1O2. However, the industry devoted too much energy on the development of more new stilbenes, lacking in-depth summaries and reflections on the characteristics of their basic structure and the mechanism of their extraordinary 1O2 quenching abilities. Therefore, we summarized the classification methods for stilbene compounds and evaluated similarities, differences and possible limitations of different classification methods. In addition, we described the role of different functional groups in stilbenes in quenching of 1O2 and summarized the quenching mechanism of 1O2 by stilbenes. By the way, the current application of stilbene compounds and their potential risks in the food industry were also mentioned in this article. The stilbenes can be used as antioxidants (especially new strategies against 1O2 oxidation) in food systems to improve the shelf life. At this stage, it is necessary to develop more effective and safe food antioxidant stilbenes based on their quenching mechanism.

Three stilbenes make difference to the antifungal effects on ochratoxin A and its precursor production of Aspergillus carbonarius.

The present study demonstrated the toxic effects of stilbenes on fungi, which were related to the structures of the stilbenes. Pterostilbene with methoxy had the best antifungal properties, followed by piceatannol, which has a catechol structure, and finally resveratrol. The inhibitory effects of stilbenes at 0.1, 0.2, 0.4, 0.8, 1.6 mM on A. carbonarius mycelia growth and spore germination were assessed by plate inhibition tests and poisoned food technique. Predicted by SPSS software, the IC50 values of resveratrol, piceatannol, and pterostilbene were 5.10, 1.80, and 0.28 mM, respectively. In addition, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that 0.4 mM pterostilbene treatment induced incompleteness of the sporangium and distortion of the mycelial structure. Antitoxic activities of stilbenes were positively correlated with their antifungal activities. 1.6 mM pterostilbene suppressed OTA synthesis better (63.48%) than 1.6 mM piceatannol (25.91%) and 1.6 mM resveratrol (22.98%). Furthermore, in the presence of stilbenes, the examined biosynthetic genes, and regulatory factors like NRPS, PKS, LaeA, HAL, bZIP, and P450 were remarkably downregulated to reduce OTA/OTB production. Increased levels of total stilbenes in grapes after fungal infestation can slow down the increased rate in OTA levels. It indicated stilbenes could be used as naturally safe and efficient compounds in food active packaging or preservatives against OTA in food.

Antifungal mechanisms of lavender essential oil in the inhibition of rot disease caused by Monilinia fructicola in postharvest flat peaches.

Lavender essential oil (LEO), a natural antimicrobial agent, is generally recognized as safe and effective in the inhibition of phytopathogenic fungi. Direct contact and fumigation (in vivo and in vitro) were used to study the fungistatic effect of LEO on Monilinia fructicola. Additionally, the effect on the ultrastructure of cells and the degree of destruction of the cell membrane of M. fructicola were revealed. In addition, the effects of LEO on the expression levels of apoptosis-related genes in M. fructicola cells were detected, and GC-MS was used to analyze the main components of LEO. LEO had a good inhibitory efficacy against M. fructicola in flat peaches, with almost complete growth inhibition at 800 µL/L. These effects were associated with the leakage of cytoplasmic contents, hyphal distortion, and spore disruption. Moreover, the expression of apoptosis RTG1 and RLM1 genes increased with LEO treatment. These results demonstrate that LEO can inhibit M. fructicola by inducing cytoplasmic membrane damage and cell apoptosis in fungi, and that the major ingredients of LEO are monoterpenes and sesquiterpenes, which are presumed to contribute to the inhibitory effects.

Based on RNA-Seq analysis identification and expression analysis of Trans-scripusinA synthesize-related genes of UV-treatment in postharvest grape fruit.

Stilbenes, an active substances closely related to resistance and quality of grapes, are rarely found in natural resources. However its cumulative amount is affected by ultraviolet radiation (UV). The purpose of this study is to screen key genes in biosynthesis of stilbenes Trans-scripusin A and explore its synthetic pathway. We tested content of stilbenes with UHPLC-QQQ-MS2, results revealed that stilbenes accumulation is positively correlated with UV-B exposure time. Then, we performed transcriptome high-throughput sequencing of grapes under treatments. Results shown that 13,906 differentially expressed genes were obtained, which were mainly enriched in three major regions (ribosome, plant-pathogen interaction and biosynthesis of flavonoid). Three genes of trans-scripusin A synthesis pathway key got by combining KEGG annotation and reference gene HsCYP1B1. Phylogenetic analysis showed that SAH genes had high homology with other hydroxylase genes, and distributed in two subgroups. Gene structure analysis showed that SAH genes contained four exons, indicating that gene has low genetic diversity. Chromosome localization revealed that SAH genes were distributed on different chromosomes, in addition, the number of gene pairs between Vitis vinifera and other species was not related to genome size of other species. The expression profiles of SAH genes in different parts of Vitis vinifera L. were analyzed using qRT-PCR analysis, results indicated that expression of SAH genes be specific to fruit part. These paper provide theoretical basis for further study of polyphenols biosynthesis pathway in grape fruits. The study provides novel insights for further understanding quality of grapes response to UV radiation.

[Double-antibody sandwich method versus indirect method of ELISA for detection of prostatic exosomal protein in the urine].

OBJECTIVE: To compare two ELISA methods for the detection of the prostatic exosomal protein (PSEP) in the urine. METHODS: Using the double-antibody sandwich (DAS) method and the indirect method of ELISA, we detected PSEP in the urine samples from 100 IIIA chronic prostatitis (CP) patients and another 100 normal healthy males. Meanwhile, we examined 30 clinical urine samples using the diluent (0.1 mol/L PBS buffer) and the urine matrix standard curves to verify the consistency of the standard diluent with the sample collected. Result: The sensitivities of DAS and indirect ELISA were 89% versus 87% and their specificities 91% versus 90%, with total consistency rates of 90% versus 88.5%, with no statistically significant difference in between. The scatter plot for the results of the PBS diluent and the urine matrix standard curves showed a good linearity (R2 = 0.999). No significant difference was found in the results of detection of the clinical urine samples in different matrices. CONCLUSIONS: Considering the characteristics of PSEP, the indirect ELISA method is more practical and feasible for the clinical detection of PSEP in the urine samples of prostatitis patients.

Fucoidan Extracted from the New Zealand Undaria pinnatifida-Physicochemical Comparison against Five Other Fucoidans: Unique Low Molecular Weight Fraction Bioactivity in Breast Cancer Cell Lines.

Fucoidan, the complex fucose-containing sulphated polysaccharide varies considerably in structure, composition, and bioactivity, depending on the source, species, seasonality, and extraction method. In this study, we examined five fucoidans extracted from the same seaweed species Undaria pinnatifida but from different geological locations, and compared them to the laboratory-grade fucoidan from Sigma (S). The five products differed in molecular composition. The amount of over 2 kDa low molecular weight fraction (LMWF) of the New Zealand crude fucoidan (S1) was larger than that of S, and this fraction was unique, compared to the other four fucoidans. The difference of molecular compositions between S and S1 explained our previous observation that S1 exhibited different anticancer profile in some cancer cell lines, compared with S. Since we observed this unique LMWF, we compared the cytotoxic effects of a LMWF and a high molecular weight fucoidan (HMWF) in two breast cancer cell lines-MCF-7 and MDA-MB-231. Results indicated that the molecular weight is a critical factor in determining the anti-cancer potential of fucoidan, from the New Zealand U. pinnatifida, as the LMWF exhibited a dose-dependent inhibition on the proliferation of breast cancer cells, significantly better than the HMWF, in both cell lines. A time-dependent inhibition was only observed in the MCF-7. Induction of caspase-dependent apoptosis was observed in the MDA-MB-231 cells, through the intrinsic apoptosis pathway alone, or with the extrinsic pathway. LMWF stimulated a dose-dependent NOS activation in the MDA-MB-231 cells. In conclusion, the fucoidan extracted from the New Zealand U. pinnatifida contains a unique LMWF, which could effectively inhibit the growth of breast cancer cell lines. Therefore, the LMWF from New Zealand U. pinnatifida could be used as a supplement cancer treatment.

Investigation of Different Molecular Weight Fucoidan Fractions Derived from New Zealand Undaria pinnatifida in Combination with GroA Therapy in Prostate Cancer Cell Lines.

Fucoidan, a sulfated polysaccharide extracted from brown seaweeds, has been shown to possess various antioxidant, anticoagulant, antiviral, and anticancer functions. In this study, we focused on low molecular weight fucoidan (LMWF) which was extracted from New Zealand Undaria pinnatifida, and investigated its anti-proliferative effects, combined with a quadruplex-forming oligonucleotide aptamer (GroA, AS1411), a powerful cell surface Nucleolin inhibitor, in prostate cancer cells. We examined LMWF (<10 kDa) and compared it with laboratory grade Fucoidan purchased from Sigma (FS), all extracted from the same seaweed species U. pinnatifida. We found that LMWF significantly improved the anti-proliferative effect of GroA, as it decreased cancer cell growth and viability and increased cell death. This research may provide the foundation for LMWF to be used against prostate cancers as a supplement therapy in combination with other therapeutic agents.

Isolation and purification of two antioxidant isomers of resveratrol dimer from the wine grape by counter-current chromatography.

Resveratrol dimers belong to a group of compounds called stilbenes, which along with proanthocyanidins, anthocyanins, catechins, and flavonols are natural phenolic compounds found in grapes and red wine. Stilbenes have a variety of structural isomers, all of which exhibit various biological properties. Counter-current chromatography with a two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water (2:5:4:5, v/v/v/v) was applied to isolate and purify stilbene from the stems of wine grape. Two isomers of resveratrol dimers trans-ε-viniferin and trans-δ-viniferin were obtained from the crude sample in a one-step separation, with purities of 93.2 and 97.5%, respectively, as determined by high-performance liquid chromatography. The structures of these two compounds were identified by (1) H and (13) C NMR spectroscopy. In addition, their antioxidant activities were assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The antioxidant activities of trans-δ-viniferin were higher than that of trans-ε-viniferin in this model. This work demonstrated that counter-current chromatography is a powerful and effective method for the isolation and purification of polyphenols from wine grape. Additionally, the DPPH radical assay showed that the isolated component trans-δ-viniferin exhibited stronger antioxidant activities than trans-ε-viniferin and a little bit weaker than vitamin E at the same concentration.

Trends in the Potential of Stilbenes to Improve Plant Stress Tolerance: Insights of Plant Defense Mechanisms in Response to Biotic and Abiotic Stressors.

Stilbenes belong to the naturally synthesized plant phytoalexins, produced de novo in response to various biotic and abiotic stressors. The importance of stilbenes in plant resistance to stress and disease is of increasing interest. However, the defense mechanisms and potential of stilbenes to improve plant stress tolerance have not been thoroughly reviewed. This work overviewed the pentose phosphate pathway, glycolysis pathway, shikimate pathway, and phenylalanine pathway occurred in the synthesis of stilbenes when plants are subjected to biotic and abiotic stresses. The positive implications and underlying mechanisms regarding defensive properties of stilbenes were demonstrated. Ten biomimetic chemosynthesis methods can underpin the potential of stilbenes to improve plant stress tolerance. The prospects for the application of stilbenes in agriculture, food, cosmetics, and pharmaceuticals industries are anticipated. It is hoped that some of the detailed ideas and practices may contribute to the development of stilbene-related products and improvement of plant resistance breeding.

Efficient binding paradigm of protein and polysaccharide: Preparation of isolated soy protein-chitosan quaternary ammonium salt complex system and exploration of its emulsification potential.

Soy protein isolate (SPI) has good emulsifying ability, but is greatly affected by the environment. The addition of polysaccharides either increases or decreases the stability of SPI. We report and prepared for the first time SPI/HACC complexes with different polysaccharide contents (SPI/HACC ratios are 1:1, 2:1 and 5:1). The binding properties, microstructure and emulsifying properties of the SPI/HACC complexes were determined and analyzed. The results showed that the interaction them is mainly through hydrogen bonding, electrostatic interaction, hydrophobic interaction and steric hindrance effect. The combination of SPI and HACC overcomes their respective limitations and the microstructure is more flat and smooth. It was also found that the emulsifying ability and concentration of SPI showed a certain correlation and the addition of HACC significantly improved the emulsifying ability and storage stability of SPI. This study shows that the prepared SPI/HACC complex has great potential for application in the food industry.

Exploring the mechanism of stilbenes to quench singlet oxygen based on the key structures of resveratrol and its analogues.

Stilbenes, especially resveratrol and resveratrol dimers, can quench singlet oxygen (1O2) effectively. Studies found resorcinol, catechol, carbon-carbon double bonds in resveratrol dimers and resveratrol monomers all contributed to quenching 1O2. However, which structures play a key role in quenching of 1O2 by stilbenes had not yet been determined. To explore it, UHPLC-QQQ-MS2 and UHPLC-QTOF-MS2 were used to analyze and compare the 1O2 quenching activities of piceatannol, resveratrol, dihydroresveratrol, pterostilbene, trimethoxystilbene and oxyresveratrol in vitro. The results showed that all six compounds exhibited some capacity to quench 1O2. Catechol [i.e., C6H4(OH)2] had the strongest capacity to quench of 1O2 amongst the stilbenes tested followed by the presence of carbon-carbon double bonds. This offers insight a route for screening for stilbenes with higher activities that might have a role in development of novel food-related antioxidants and functional foods with potential health benefits.

Exogenous Phytosulfokine α (PSKα) Alleviates Chilling Injury of Kiwifruit by Regulating Ca2+ and Protein Kinase-Mediated Reactive Oxygen Species Metabolism.

Kiwifruit fruit stored at low temperatures are susceptible to chilling injury, leading to rapid softening, which therefore affects storage and marketing. The effect of 150 nM mL-1 of exogenous phytosulfokine α (PSKα) on reactive oxygen species (ROS) metabolism, Ca2+ signaling, and signal-transducing MAPK in kiwifruit, stored at 0 °C for 60 days, was investigated. The results demonstrated that PSKα treatment effectively alleviated chilling injury in kiwifruit, with a 15% reduction in damage compared to the control on day 60. In addition, PSKα enhanced the activities and gene expression levels of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), Ca2+-ATPase, and mitogen-activated protein kinase (MAPK). In contrast, the activities and gene expression levels of NADPH oxidase (NOX) were inhibited, leading to a lower accumulation of O2- and H2O2, which were 47.2% and 42.2% lower than those in the control at the end of storage, respectively. Furthermore, PSKα treatment enhanced the calmodulin (CaM) content of kiwifruit, which was 1.41 times that of the control on day 50. These results indicate that PSKα can mitigate chilling injury and softening of kiwifruit by inhibiting the accumulation of ROS, increasing antioxidant capacity by inducing antioxidant enzymes, activating Ca2+ signaling, and responding to MAPK protein kinase. The present results provide evidence that exogenous PSKα may be taken for a hopeful treatment in alleviating chilling injury and maintaining the quality of kiwifruit.

Characteristic Structures of Different Stilbenes Distinguish the Impact on Ochratoxin A Biosynthesis Intermediate Pathway and Metabolites of Aspergillus carbonarius.

In this paper, we accurately pinpointed the inhibition sites of ochratoxin A (OTA) synthesis pathway in Aspergillus carbonarius acted by stilbenes from the perspective of oxidative stress and comprehensively explored the relationship between the physical and chemical properties of natural polyphenolic substances and their biochemical properties of antitoxin. To facilitate the application of ultra-high-performance liquid chromatography and triple quadrupole mass spectrometry for real-time tracking of pathway intermediate metabolite content, the synergistic effect of Cu2+-stilbenes self-assembled carriers was utilized. Cu2+ increased the generation of reactive oxygen species to accumulate mycotoxin content, while stilbenes had the inhibitory effect. The impact of the m-methoxy structure of pterostilbene on A. carbonarius was found to be superior to that of resorcinol and catechol. The m-methoxy structure of pterostilbene acted on the key regulator Yap1, downregulated the expression of antioxidant enzymes, and accurately inhibited the halogenation step of the OTA synthesis pathway, thus accumulating the content of OTA precursors. This provided a theoretical basis for the extensive and efficient application of a wide range of natural polyphenolic substances for postharvest disease control and quality assurance of grape products.

Development of functional, sustainable pullulan-sodium alginate-based films by incorporating essential oil microemulsion for chilled pork preservation.

Developing safe, eco-friendly, and functionally edible packaging materials has attracted global attention. Essential oils, can be incorporated into packaging materials as antioxidant and antibacterial agents. However, their high volatility and discontinuous film matrix issues may cause a rough film surface, limiting the application in food packaging. In this study, thyme essential oil microemulsion (TEO-M) was prepared and incorporated into a pullulan-sodium alginate (PS) film. The TEO-M incorporation endowed the PS film with antioxidant and UV protection properties. The antioxidant activities of the TEO-M-incorporated PS film were significantly better than those of the TEO-C (thyme essential oil coarse emulsion)-incorporated PS film. In comparison to TEO-C, the distribution of TEO-M in the film is more uniform. Lipid oxidation and the growth of microorganisms in chilled pork were inhibited by incorporating TEO-M at a concentration of 50 mg/mL in the PS film (PS-50M). After 10 days of storage at 4 °C, the total viable count (TVC) of chilled pork preserved in the PS-50M material was significantly reduced compared to the control group (P < 0.05). This study shows that incorporating TEO-M in the PS film provides a method for applying essential oils in food packaging, which may have great potential in the food industry.

Migration of connective tissue-derived cells is mediated by ultra-low concentration gradient fields of EGF.

The directed migration of cells towards chemical stimuli incorporates simultaneous changes in both the concentration of a chemotactic agent and its concentration gradient, each of which may influence cell migratory response. In this study, we utilized a microfluidic system to examine the interactions between epidermal growth factor (EGF) concentration and EGF gradient in stimulating the chemotaxis of connective tissue-derived fibroblast cells. Cells seeded within microfluidic devices were exposed to concentration gradients established by EGF concentrations that matched or exceeded those required for maximum chemotactic responses seen in transfilter migration assays. The migration of individual cells within the device was measured optically after steady-state gradients had been experimentally established. Results illustrate that motility was maximal at EGF concentration gradients between .01- and 0.1-ng/(mL.mm) for all concentrations used. In contrast, the number of motile cells continually increased with increasing gradient steepness for all concentrations examined. Microfluidics-based experiments exposed cells to minute changes in EGF concentration and gradient that were in line with the acute EGFR phosphorylation measured. Correlation of experimental data with established mathematical models illustrated that the fibroblasts studied exhibit an unreported chemosensitivity to minute changes in EGF concentration, similar to that reported for highly motile cells, such as macrophages. Our results demonstrate that shallow chemotactic gradients, while previously unexplored, are necessary to induce the rate of directed cellular migration and the number of motile cells in the connective tissue-derived cells examined.

Control of apple blue mold by Pichia pastoris recombinant strains expressing cecropin A.

Recombinant Pichia pastoris yeasts expressing cecropin A (GS115/CEC), was evaluated for the control of the blue mold of apple caused by Penicillium expansum due to cecropin A peptide's effective antimicrobial effects on P. expansum spores by the thiazolyl blue (MTT) assay. Then, the protein concentration was determined and it was expressed at high levels up to 14.2 mg/L in the culture medium. Meanwhile, the population growth was assayed in vivo. The population growth of recombinant strain GS115/CEC was higher than that of non-transformed strain GS115 in red Fuji apples wounds. Recombinant yeast strains GS115/CEC significantly inhibited growth of germinated P. expansum spores in vitro and inhibited decay development caused by P. expansum in apple fruits in vivo when compared with apple fruits inoculated with sterile water or the yeast strain GS115/pPIC (plasmid pPIC9k transformed in GS115). This study demonstrated the potential of expression of the antifungal peptide in yeast for the control of postharvest blue mold infections on pome fruits.

Changes in Polyphenolic Compounds of Hutai No. 8 Grapes during Low-Temperature Storage and Their Shelf-Life Prediction by Identifying Biomarkers.

The aim of this experiment was to assess the effect of different storage temperatures on the texture quality, phenolic profile, and antioxidant capacity of a grape. Fresh grapes were stored at 4 and 25 °C for nine days and sampled on alternate days. The hardness, total phenolics, total flavanones, total flavanols, total anthocyanin content, antioxidant activity, differential metabolite screening, and key gene expression were evaluated. In addition, four phenolic compounds were screened out as differential metabolites in response to storage temperature by OPLS-DA analysis. The results showed that the fruit firmness was better maintained in low-temperature storage and the storage life was longer than that at 25 °C. During the whole storage process, the contents of phenolics, flavanones, flavanols, and anthocyanins all showed an increasing trend first and then decreased regardless of what temperature. Since the antioxidant capacity of a grape was positively correlated with the contents of total phenols and total flavonoids, the same trend was also shown. However, the grape's phenolic compound content and antioxidant activity were higher at 25 °C than at 4 °C. Furthermore, through qualitative and quantitative analysis of 16 monomeric phenols, this study selected catechin, 1-O-vanilloyl-ß-d-glucose, p-coumaric acid 4-glucoside, and resveratrol-3-O-glucoside as the main differentially expressed metabolites at the two temperatures. In conclusion, for a short shelf life or immediate consumption, keeping grapes at room temperature is more beneficial to obtain high antioxidants. However, if the goal is to prolong the storage period of the fruit, keeping the fruit at 4 °C is recommended.

Molecular cloning of a PR-5 like protein gene from cherry tomato and analysis of the response of this gene to abiotic stresses.

LePR-5, a putative PR5 like protein gene was amplified from a cherry tomato (Lycopersicon esculentum), which encodes a precursor protein of 250 amino acid residues, and shares high degrees of homology with a number of other PR5 genes. Expression of LePR-5 in different tomato organs was analyzed with Semi-quantitative RT-PCR, showing that LePR-5 expressed at different levels in leaves, stems, roots, flowers and fruits. In addition, expression of LePR-5 under different abiotic stresses was carried out at different time points. Three of the four tested abiotic stimuli, ethophen, salicylic acid and methyl jasmonate, triggered a significant induction of LePR-5 after treatment. However, LePR-5 was weaker induced by abscisic acid than by others. The positive responses of LePR-5 to the three abiotic stimuli suggested that LePR-5 may play an important role in response to abiotic stresses, and it may also be involved in plant defense system against pathogens. In addition, different expression patterns between tomato fruit and seedling suggested that LePR-5 may play a distinctive role in the defensive system protecting tomato fruit and seedling.

Epigallocatechin Gallate (EGCG) Promotes the Immune Function of Ileum in High Fat Diet Fed Mice by Regulating Gut Microbiome Profiling and Immunoglobulin Production.

This study aimed to investigate the regulatory effect of epigallocatechin gallate (EGCG) on the composition of the gut microbiome, the transcriptomic profiling of ileum, and their interplay in high fat diet (HFD) induced obese mice. Intragastric administration of EGCG to C57BL/6J mice for 14 consecutive weeks remarkably decreased HFD induced excessive fat deposition (p < 0.001), and the increment of serum TG, TC, HDL-C (p < 0.05), as well as improved glucose tolerance (p < 0.001). EGCG shifted the gut microbiota mainly by elevating the relative abundance of Parasutterrlla, Bacteroides, and Akkermansia (p < 0.01), decreasing that of norank_f_Erysipelotrichaceae, unclassified_f_Ruminococcaceae, Anaerotruncus, Roseburia, norank_Lachnospiraceae, and Lachnospiraceae_UCG_006 (p < 0.01) at the genus level. In addition, EGCG affected the transcriptomic profiling of ileum, and the differentially expressed (DE) genes after HFD or/and EGCG treatment were mostly enriched in the immune reaction of ileum, such as the GO term of "immune effector process" and "phagocytosis, recognition." Furthermore, the KEGG category of "immune diseases," "immune system," and "infection diseases: bacterial" were commonly enriched by the DE genes of the two treatments. Among those DE genes, 16 immunoglobulins heavy chain variable region encoded genes (Ighvs) and other immunity-related genes, such as complement component 2 (C2), interferon-induced transmembrane protein 1 (Iftm1), polymeric immunoglobulin receptor (pigR), and alanyl aminopeptidase (Anpep), were highly correlated with the shifted microbes in the gut (p < 0.05, absolute r > 0.5). Overall, the results suggested that EGCG ameliorated the HFD induced metabolic disorder mainly by regulating gut microbiome profiling and the immunoglobulin production of ileum, while the genes expressed in the ileum, especially Ighvs, C2, Iftm1, pigR, and Anpep, might play important roles in coordinating the immunity of mice regarding the gut microbes and the host interactions.