內(nèi)容: Bacillus subtilis JZXJ-7 isolated from shrimp paste can significantly degrade histamine under salt stress but the mechanism is unclear. This study aims to evaluate the effect of 170 and 340 mmol/L NaCl on B. subtilis JZXJ-7 growth, histamine degradation, antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD) and glutathione S-transferase (GST)) activities and Na+/K+-ATPase activity. Furthermore, comparative metabolomics was used to investigate histamine biodegradation mechanism by B. subtilis JZXJ-7 subjected to salt stress. Both 170 and 340 mmol/L NaCl promoted B. subtilis JZXJ-7 growth in late stages of reproduction (32?48 h), increased histamine degradation rate by 64.85% and 79.87% (P < 0.05), Na+/K+-ATPase activity to 6.28 (P < 0.05) and 11.63 U/mg (P < 0.01) respectively. NaCl treatment significantly increased the activities of CAT, GST and SOD (P < 0.05), amino acids and its metabolites (33.39%), benzene and substituted derivatives (12.05%), heterocyclic compounds (10.62%), organic acids and derivatives (9.75%), aldehydes, ketones, esters (5.59%) and nucleotides and its metabolites (4.58%). Metabolite set enrichment analysis revealed NaCl induced differential metabolic pathways of D-glutamine, D-glutamate, L-arginine, L-proline, histidine and glycerophospholipids, L-lysine degradation, and aminoacyl-tRNA biosynthesis. Exposure to 340 mmol/L NaCl up-regulated carbohydrate, glutathione and glycerophospholipid metabolism. The new insights into the mechanism of salt stress to promote B. subtilis JZJX-7 growth, energy metabolic pathways and to degrade histamine provide the theoretical basis for application of B. subtilis JZXJ-7 in food fermentation industry.

內(nèi)容: Gomphus purpuraceus is an ancient wild edible mushroom. However, the niche and lignocellulose degradation system of G. purpuraceus have remained cryptic. In the current study, transcriptome and proteome sequencing of G. purpuraceus in four mediums was performed. A total of 3 489 differentially expressed genes (DEGs) and 891 differentially expressed proteins (DEPs) were screened out. For the lignocellulose degradation system, a total of 61 expressed genes were annotated, including 19 genes encoding cellulase, 8 genes encoding hemicellulase, 5 genes encoding pectinase, 22 genes encoding lignin oxidase, and 7 lignin degrading auxiliary enzyme. From two-omics, morphology, and enzyme activities, we speculated that G. purpuraceus might have a limited capacity to degrade polysaccharides (starch and lignocellulose). In addition, trace amount of fumonisins (FB1 and FB2) were found in the G. purpuraceus. These results provided a new perspective for understanding the key pathways and hub genes involved in carbon metabolism of G. purpuraceus development.

內(nèi)容: The dark blue pigment (DBP) is a health ingredient from Vaccinium bracteatum Thunb. leaves used as a functional food supplement. However, the details of transepithelial absorption on the intestinal epithelial cells are barely understood. This study aimed to clarify the absorption properties of DBP in the Caco-2 cell monolayer model and evaluate the effect on the endo-metabolism and barrier function of Caco-2 cells. The results showed that the DBP did not show the dose-dependent toxic effect to Caco-2 cells between 0.25 and 1.5 mg/mL, which did not cause disorder in the normal cell metabolism and absorption activity. The Caco-2 cell monolayer model could absorb DBP by passive and active transport, and the absorptive pattern was dose-dependent when the concentration was more than 0.25 mg/mL. During DBP absorption, an increase in mRNA and protein expressions of glucose transporters demonstrated that the glucose transporters were the potential transporter of DBP. But the glucose transport amounts were significantly lowered after 30 min of DBP treatment, indicating that DBP owned the inhibitory effect on glucose transportation. Furthermore, DBP also owned protective effects on the barrier function of intestinal epithelial cells.

內(nèi)容: Cronobacter spp. has strong resistance to desiccation and high permeability in Enterobacteriaceae, and powdered infant formula (PIF) is one of the main contamination routes. In recent years, the contamination of Cronobacter spp. in PIF incidents occurs from time to time, causing infant serious diseases or death. In this investigation, matrix-assisted laser desorption/ionization time of flight mass spectrometry was used to identify the phenotypes of 35 Cronobacter strains isolated from PIF and its processing environment. Subsequently, the isolates were evaluated for drying and osmotic pressure tolerance. The results showed that the deactivation rate of the strains ranged from 9.01% to 77.57%, and the highest osmotic pressure condition the strains could tolerate was 6 g/100 mL NaCl. In addition, there was a positive correlation between biofilm formation ability and desiccation resistance. Combined with transcriptomics, Cronobacter spp. could activate biofilm synthesis, produce more trehalose, accumulate betaine and electrolytes to stabilize intracellular structure under the two treatment conditions. A total of 31 and 43 genes were found related to desiccation and permeability resistance, respectively. And some genes (cysM, thuF, ycjO, etc.) were found to be associated with two tolerances for the first time.

內(nèi)容: The aim of this paper was to study the effect of combination of Lactobacillus strains and tryptophan (Trp)-rich diet on the intestinal barrier function of Balb/c mice exposed to a cocktail of antibiotics and dextran sodium sulfate. Several Lactobacillus strains isolated from the healthy human fecal sample was found to utilize Trp to produce indole derivatives. The results of Trp metabolism indicated that the ability of Lactobacillus to metabolize Trp to produce indole-3-lactic acid (ILA), indole-3-carboxaldehyde (I3C), and indole-3-acetic acid varies in vitro and in vivo. The effect of Lactobacillus with high-yielding indole derivatives on disease activity index, colon length, and intestinal permeability was significantly better than that of Lactobacillus with low-yielding indole derivatives in a high Trp diet. And Lactobacillus combined with Trp intervention also had a certain regulatory effect on the intestinal flora of male BALB/c mice. Among them, Lactiplantibacillus plantarum DPUL-S164 produced more ILA both in vivo and in vitro, and the combination of L. plantarum DPUL-S164 and Trp significantly decreased the expression level of the serum pro-inflammatory cytokine interleukin (IL)-6 and increased the expression level of the anti-inflammatory cytokine IL-10, significantly improved the number of goblet cells in the mouse mucous layer and increased mucin and tight junction protein expression. Furthermore, L. plantarum DPUL-S164 combined with Trp intervention activated the aryl hydrocarbon receptors (AhR) signaling pathway. Furthermore, we found that the expression of colonic tight junction protein was positively correlated with the expression of colonic AhR, and the expression of AhR was positively correlated with the concentrations of ILA and I3C in vivo. Therefore, we conclude that the ILA as AhR ligand produced by L. plantarum DPUL-S164 regulated the AhR pathway, thus up-regulating the expression of the tight junction protein and protecting the integrity of the epithelial barrier.

內(nèi)容: In-depth knowledge of the microbes responsible for biogenic amine (BA) production during soy sauce fermentation remains limited. Herein, the variations in the BA profiles, microbial communities, and microbes involved in BA production during the fermentation of soy sauce through Japanese-type (JP) and Cantonese-type (CP) processes were compared. BA analysis revealed that the most abundant BA species were putrescine, tyramine, and histamine in the later three stages (1 187.68, 785.16, and 193.20 mg/kg on average, respectively). The BA profiles differed significantly, with CP samples containing higher contents of putrescine, tyramine, and histamine (P < 0.05) at the end of fermentation. Metagenomic analysis indicated that BA-producing genes exhibited different abundance profiles, with most genes, including speA, speB, arg, speE, and tyrDC, having higher abundances in microbial communities during the CP process. In total, 15 high-quality metagenome-assembled genomes (MAGs) were retrieved, of which 10 encoded at BA production-related genes. Enterococcus faecium (MAG10) and Weissella paramesenteroides (MAG5) might be the major tyramine producers. The high putrescine content in CP might be associated with the high abundance of Staphylococcus gallinarum (MAG8). This study provides a comprehensive understanding of the diversity and abundance of genes involved in BA synthesis, especially at the species level, during food fermentation.

內(nèi)容: Plant polyphenols are potential substitutes for clinical α-glucosidase inhibitors. Our previous studies indicated that prodelphinidins from Chinese bayberry leaves (BLPs) have stronger α-glucosidase inhibitory activity than other common polyphenols, but they have no safe history of consumption. There is a reasonable prospect that prodelphinidins from Chinese bayberry fruits (BFPs) can improve postprandial hyperglycemia, though known active components are only myricetin and cyanidin-3-O-glucoside. Hence, the aim of this study was to analyze structure and hypoglycemic effect of BFPs of “Biqi” (BQPs) and “Dongkui” (DKPs) cultivars, and compare their difference with BLPs. The contents of BQPs and DKPs were (221.73 ± 0.60) and (136.82 ± 4.33) mg epicatechin (EC) equivalents/g dry weight, respectively. The most subunits were epigallocatechin gallate along with a small amount of epigallocatechin, epicatechin gallate and EC connected by B-type linkages and a small portion of A-type linkages with mean polymerization degree of 4.25 and 4.08, respectively. Importantly, BQPs and DKPs were α-glucosidase inhibitors with half inhibitory concentration of 11.91 and 9.47 μg/mL respectively, which were significantly stronger than BLPs. DKPs could also improve postprandial hyperglycemia of normal mice and high fat diet-induced type II diabetic mice. Therefore, edible prodelphinidins, which have stronger hypoglycemic effect than BLPs, were first found in Chinese bayberry fruits.

內(nèi)容: Aflatoxin B1 (AFB1) is a carcinogenic toxin naturally produced in most food crops that severely threaten human health, and effective methods are urgent to improve the detection accuracy. Herein an indirect competitive immunosorbent approach was elaborately developed based on high-affinity immunoglobulin G (IgG) coupled CuO-anchored Fe3O4 nanozymes for precise and ultrasensitive detection of AFB1 in food crops including peanut, corn and wheat. The high-affinity nanozymes were fabricated by the assembly of inner core Fe3O4 nanoparticles and mesoporous silica capping layer, CuO further situated within large aperture of the coating layer via in-situ growth, and then conjugated with ligand rabbit anti-mouse IgG, which can specifically bind with AFB1. The results showed the hybrid high-affinity nanozymes displayed enhanced peroxidase-mimic activities and catalytic performances, achieving a linear range of 0.06?61.93 (lg(ng/mL)) and a detection limit of 0.003 7 ng/mL, 30 times better than that of the conventional enzyme-linked immunosorbent assay. The constructed nanozymes were successfully applied to the detection of AFB1 in food products with an average spiked recovery of 96.53% and relative standard deviations less than 2.8%. Therefore, the accurate hybrid nanozymes may serve for AFB1 detection in various foods in future.

內(nèi)容: Uric acid (UA) is a naturally antioxidant that is strongly associated with the development and progression of Parkinson’s disease (PD). The purine diet is an important exogenous pathway that modulates blood UA levels. Deep brain stimulation (DBS) is an important tool for PD treatment. This study aimed to explore the effects of preoperative purine diet on the prognosis of patients with PD after DBS. Sixty-four patients with PD who underwent DBS were included in this study, and their clinical data, blood UA levels, and daily purine intake. Patients were followed up for improvement 1 year after surgery. We found that patient higher purine intake was strongly associated with the rate of improvement after DBS and was a protective factor for patient prognosis. Daily purine intake from meat and seafood was significantly higher in the responsive patients than in the less-responsive patients. Mediation analysis showed that UA mediated 78% of the effect of purine intake on motor symptom improvement after DBS. In summary, we observed that purine intake is strongly associated with the rate of improvement in motor symptoms after subthalamic nucleus-DBS in patients with PD. This study provides a reference for preoperative diet planning in patients with PD undergoing DBS.

內(nèi)容: Emerging evidence supports that sleep disorders are the main risk factor for sporadic Alzheimer’s disease (AD), and iron dysregulation may be the link between them. Our previous studies have confirmed that ketogenic diet (KD) can prevent chronic sleep deprivation-induced AD. However, it is uncertain whether exogenous ketones supplements (EKS), as an alternative intervention, have the same effects as KD. Thus, we investigated the prophylactic efficiency of EKS on chronic sleep deprivation-induced AD and reveal the underlying mechanism focus on iron metabolism. We observed that the prophylactic efficacy of EKS against chronic sleep deprivation-induced AD was comparable to that of KD. Meanwhile, our results suggest that both EKS and KD inhibited iron metabolism disorder through regulation of iron metabolism-related proteins. Moreover, we found that both EKS and KD reduced hippocampal mitochondrial dysfunction and iron-mediated lipid peroxides. Furthermore, EX527 (silent information regulator 1 (Sirt1) inhibitor), mostly abrogated these above protections of EKS, suggesting that the prophylactic effect of EKS on AD is partly dependent on Sirt1. Our findings provide novel evidence that EKS can be developed as functional foods to prevent or delay the development of AD, particularly in individuals with sleep disorders.