Novel aptasensor based on polyaniline functionalized carboxylated dobby carbon nanotubes and molybdenum disulfide for endotoxin detection.

Endotoxins, also known as lipopolysaccharides (LPS), are present within the cell walls of Gram-negative bacteria and are released upon cellular death, which can pose a significant risk to human and animal health. Due to the minimal amount of endotoxin required to trigger an inflammatory response in human body, the demand for sensitive methods with low endotoxin detection limits is essential necessary. This paper presents a straightforward aptamer sensor which can enhance the conductivity and specific surface area of molybdenum disulfide (MoS2) by incorporating carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) and polyaniline (PANI). Doping with gold nanoparticles (AuNPs) improves biocompatibility and sensitivity while providing binding sites for thiolated endotoxin-binding aptamers (LBA). This biosensor achieved a remarkable detection limit as low as 0.5 fg mL-1, enabling trace-level identification of LPS. It also exhibits excellent repeatability, selectivity, and stability, facilitating rapid and accurate LPS detection. Moreover, this method demonstrates high recovery rates and specificity for LPS analysis in food samples, showcasing its promising application prospects in trace-level LPS detection within the food industry.

A novel neuroprotective peptide YVYAETY identified and screened from Flammulina velutipes protein hydrolysates attenuates scopolamine-induced cognitive impairment in mice.

Flammulina velutipes protein hydrolysates are known for their abundant amino acids and excellent developmental values. This study aimed to identify and screen neuroprotective peptides from F. velutipes protein hydrolysates in vitro and validate the protective effects of YVYAETY on memory impairment in scopolamine-induced mice. The F. velutipes protein was hydrolyzed by simulated gastrointestinal digestion, followed by purification through ultrafiltration and gel chromatography. The fraction exhibiting the strongest neuroprotective activity was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The main identified peptides (SDLKPADF, WNDHYY, YVYAETY, and WFHPLF) effectively mitigated excessive ROS production by increasing SOD and GSH-px activities while inhibiting cell apoptosis and mitochondrial membrane potential (MMP) collapse against oxidative stress in Aß25-35-induced HT22 cells. By molecular docking, the interaction between peptides and the active site of the Keap1-Kelch domain reveals their capacity to regulate the Keap1/Nrf2/HO-1 pathway. In vitro, the peptide YVYAETY had the best effect and can be further validated in vivo. The behavioral tests showed that YVYAETY improved scopolamine-induced cognitive impairment in mice. YVYAETY also alleviated neuron damage including neuron vacuolation and pyknotic nuclei in the hippocampus. Furthermore, it significantly inhibited oxidative stress and suppressed the activation of the Nrf2 pathway. Therefore, this study revealed that YVYAETY had the potential to serve as a novel neuroprotective agent.

Dietary intake of whole king oyster mushroom (Pleurotus eryngii) attenuated obesity via ameliorating lipid metabolism and alleviating gut microbiota dysbiosis.

There is a growing interest in employing whole food-based strategies to prevent chronic diseases, owing to the potential synergistic interactions among various bioactive components found within whole foods. The current research aimed to determine inhibitory effects of the whole edible mushroom Pleurotus eryngii (WPE) on high-fat diet (HFD)-induced obesity in mice. Our results showed that dietary intake of WPE significantly inhibited the abnormal gain of body weight and adipose tissue weight, improved glucose tolerance, and ameliorated the serum biochemical parameters in HFD-fed mice. The histological analysis illustrated that the severity of non-alcoholic fatty liver induced by HFD was significantly reduced by WPE. Oral intake of WPE profoundly modulated the mRNA levels of hepatic genes involved in lipid metabolism and also increased the level of short-chain fatty acids in the mouse cecum. Moreover, WPE alleviated the HFD-induced gut microbiota dysbiosis, increasing the abundance of beneficial bacteria (Akkermansia, Lactobacillus, Bifidobacterium, and Sutteralla), and decreasing the harmful ones (rc4-4, Dorea, Coprococcus, Oscillospira, and Ruminococcus). These findings presented new evidence supporting that WPE could be used as a whole food-based strategy to protect against obesity and obesity-driven health problems.

Structure and immunostimulatory activity studies on two novel Flammulina velutipes polysaccharides: revealing potential impacts of →6)-α-D-Glcp(1→ on the TLR-4/MyD88/NF-κB pathway.

Two novel Flammulina velutipes (F. velutipes) polysaccharides, FVPH1 and FVPH2, were isolated and purified after hot water extraction. The structural characterization revealed that the backbone of FVPH1 consisted mainly of →6)-α-D-Glcp(1→, →3,4)-α-D-Galp(1→, →4)-α-L-Fucp(1→, and →4)-ß-D-Manp(1→, while the backbone of FVPH2 consisted of →3)-α-D-Galp(1→, →3,4)-α-D-Manp(1→,→6)-α-D-Glcp(1→. The branches of FVPH1 contained →6)-α-D-Glcp(1→ and α-D-Glcp(1→ and the branches of FVPH2 consisted of →3)-α-D-Galp(1→, →6)-α-D-Glcp(1→, and ß-L-Fucp(1→. FVPH2 exhibited significantly better immunostimulatory activity than FVPH1 (P < 0.05), as evidenced by the increased expression of NO, IL-1ß, IL-6, and TNF-α and pinocytic activity of RAW264.7 cells. As the most abundant structure in the polysaccharides of F. velutipes, the content of →6)-α-D-Glcp(1→ might play a crucial role in influencing the immunostimulatory activity of F. velutipes polysaccharides. The F. velutipes polysaccharide with a lower content of →6)-α-D-Glcp(1→ and a higher branching degree could significantly enhance the immunostimulatory activity of F. velutipes polysaccharides via activating the TLR-4/MyD88/NF-κB pathway more effectively.

Gadolinium deposition in the liver and brain in a rat model with liver fibrosis after intravenous administration of gadoxetate disodium.

Objectives: To investigate gadolinium deposition in the liver and brain in a rat model with liver fibrosis (LF) after intravenous administration of gadoxetate disodium (GD) and the histological effects of gadolinium deposition in the liver and brain. Methods: Adult male Sprague-Dawley rats were randomly assigned to one of the three groups: 1) LF group received intraperitoneal injection of carbon tetrachloride (CCl4) for 9 weeks alone; 2) LF&GD group received CCl4 and intravenous administration of GD (for 5 consecutive days); 3) GD group received olive oil and GD. Seven days after the final injection of GD, the deep cerebellar nuclei (DCN) and liver were excised to determine gadolinium concentrations via inductively coupled plasma mass spectrometry, and histologic staining was performed. Bonferroni's post-hoc test and Wilcoxon rank sum test were used to compare the differences between the three groups. Results: The concentrations of retained gadolinium in the liver in the LF&GD group (2.18 ± 0.44 µg/g) were significantly greater compared to the LF group (0.02 ± 0.01 µg/g, P < 0.001) and GD group (0.37 ± 0.11 µg/g, P < 0.001). Also, the concentrations of retained gadolinium in DCN were increased in the LF&GD group (0.13 ± 0.06 µg/g) compared to the LF group (0.01 ± 0.00 µg/g, P < 0.001) and GD group (0.06 ± 0.02 µg/g, P = 0.019). No histopathological alterations were detected in the liver and DCN between LF&GD group and LF group. Conclusions: LF aggravated gadolinium deposition in the liver and DCN after administration of GD. However, no significant acute histological alterations were observed due to gadolinium deposition.

Pleurotus ostreatus is a promising candidate of an edible 3D printing ink: Investigation of printability and characterization.

The 3D printing (3DP) technology shows great potential in the food industry, but the development of edible ink is currently insufficient. Pleurotus ostreatus (P. ostreatus) emerges as a novel promising candidate. In this study, a mixed ink was obtained by incorporating butter into P. ostreatus. The effects of different ratios of P. ostreatus and butter, as well as the influence of ink steaming were investigated on 3D printed products. The results indicated that all inks of the P. ostreatus system exhibited positive shear-thinning behavior, and the system maintained stable intermolecular hydrogen bonding when P. ostreatus powder concentration was 40 % (w/v). Furthermore, the L* value of the system was elevated for butter adding. The system with steaming exhibited superior stabilized molecular structure compared to the native system, particularly with a steaming duration of 5 min, showcasing its outstanding supporting capacity. This study suggests that P. ostreatus is a promising candidate in 3DP for the development of an edible ink that promotes innovation and nutritional food.

The effect of in vitro digestion on the interaction between polysaccharides derived from Pleurotus eryngii and intestinal mucus.

Pleurotus eryngii polysaccharides (PEPs) have been proven to display multiple activities through digestive system action, from which the digestion products should first interact with intestinal mucus (MUC), followed by the function of intestinal cells. Hence, possible interacting characterizations between MUC and in vitro simulated digestion products of P. eryngii polysaccharides (DPEPs) and PEP were carried out in the present study. Results showed that both PEP and DPEP could significantly interact with MUC. Moreover, digestion can modify the interaction between polysaccharides and MUC; the degree of interaction also changes with time incrementing. Viscosity could be decreased after digesting. According to the zeta potential and stability analysis result, the digestive behavior could be regular and stable between polysaccharides and MUC interactions. Following fluorescence and infrared spectra, the structure of polysaccharides and mucin might be changed by digestion between polysaccharides and MUC. The study indicates that the interaction formed between DPEP and MUC might indirectly impact the exercise and immune activities of polysaccharides and influence the transportation of other nutrients. Overall, our results, the absorption and transport pathways of PEP, can be initially revealed and may provide a novel research viewpoint on the active mechanism of PEP in the intestinal tract.

Improved bioavailability and antioxidation of ß-carotene-loaded biopolymeric nanoparticles stabilized by glycosylated oat protein isolate.

The limited bioavailability of ß-carotene hinders its potential application in functional foods, despite its excellent antioxidant properties. Protein-based nanoparticles have been widely used for the delivery of ß-carotene to overcome this limitation. However, these nanoparticles are susceptible to environmental stress. In this study, we utilized glycosylated oat protein isolate to prepare nanoparticles loaded with ß-carotene through the emulsification-evaporation method, aiming to address this challenge. The results showed that ß-carotene was embedded into the spherical nanoparticles, exhibiting relatively high encapsulation efficiency (86.21 %) and loading capacity (5.43 %). The stability of the nanoparticles loaded with ß-carotene was enhanced in acidic environments and under high ionic strength. The nanoparticles offered protection to ß-carotene against gastric digestion and facilitated its controlled release (95.76 % within 6 h) in the small intestine, thereby leading to an improved in vitro bioavailability (65.06 %) of ß-carotene. This improvement conferred the benefits on ß-carotene nanoparticles to alleviate tert-butyl hydroperoxide-induced oxidative stress through the upregulation of heme oxygenase-1 and NAD(P)H quinone dehydrogenase 1 expression, as well as the promotion of nuclear translocation of nuclear factor-erythroid 2-related factor 2. Our study suggests the potential for the industry application of nanoparticles based on glycosylated proteins to effectively deliver hydrophobic nutrients and enhance their application.

Integrin-Targeted Theranostic Nanoparticles for Clinical MRI-Traceable Treatment of Liver Fibrosis.

Liver fibrosis is the critical stage in the development of chronic liver disease (CLD), from simple injury to irreversible cirrhosis. Timely detection and intervention of liver fibrosis are crucial for preventing CLD from progressing into a fatal condition. Herein, we developed iron oxide (Fe3O4) nanoparticles (IONPs) and ferulic acid (FA) coencapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), followed by surface modification with cRGD peptides (cRGD-PLGA/IOFA) for integrin-targeted clinical magnetic resonance imaging (MRI)-traceable treatment of liver fibrosis. The cRGD peptide linked on the surface of the PLGA/IOFA NPs could specifically bind to the overexpressed integrin αvß3 on activated hepatic stellate cells (HSCs) in the fibrotic liver, enabling the high-sensitive clinical MR imaging (3 T) and precise staging of liver fibrosis. The FA encapsulated in cRGD-PLGA/IOFA showed excellent efficacy in reducing oxidative stress and inhibiting the activation of HSCs through the transforming growth factor-ß (TGF-ß)/Smad pathway. Notably, the IONPs encapsulated in cRGD-PLGA/IOFA NPs could alleviate liver fibrosis by regulating hepatic macrophages through the NF-κB pathway, lowering the proportion of Ly6Chigh/CD86+, and degrading collagen fibers. The FA and IONPs in the cRGD-PLGA/IOFA produced a synergistic enhancement effect on collagen degradation, which was more effective than the IONPs treatment alone. This study demonstrates that cRGD-PLGA/IOFA NPs could effectively relieve liver fibrosis by acting on macrophages and HSCs and provide a new strategy for the clinical MRI-traceable treatment of liver fibrosis.

Oat protein isolate-Pleurotus ostreatus ß-glucan conjugate nanoparticles bound to ß-carotene effectively alleviate immunosuppression by regulating gut microbiota.

Individuals with immune disorders cannot establish an adequate defense to pathogens, leading to gut microbiota dysbiosis. ß-Carotene can regulate immune response, but its bioavailability in vivo is very low. Herein, we developed a glycosylated oat protein-based nanoparticle to improve the application of ß-carotene for mitigating cyclophosphamide-induced immunosuppression and gut microbiota imbalance in mice. The results showed that the nanoparticles facilitated a conversion of ß-carotene to retinol or retinyl palmitate into the systemic circulation, leading to an increased bioavailability of ß-carotene. The encapsulated ß-carotene bolstered humoral immunity by elevating immunoglobulin levels, augmenting splenic T lymphocyte subpopulations, and increasing splenic cytokine concentrations in immunosuppressed mice. This effect was accompanied by the alleviation of pathological features observed in the spleen. In addition, the encapsulated ß-carotene restored the abnormal gut microbiota associated with immunosuppression, including Erysipelotrichaceae, Akkermansia, Bifidobacterium and Roseburia. This study suggested that nanoparticles loaded with ß-carotene have great potential for therapeutic intervention in human immune disorders by specifically targeting the gut microbiota.

Interactions between intestinal microbial fermentation products of Pleurotus eryngii polysaccharide with gut mucus.

Recently, Pleurotus eryngii (P. eryngii) polysaccharide (PEP) has received a lot of attention from many researchers as the primary active substance. The PEP influences the gut microbiota in several ways, including the interaction of fermentation products with the intestinal mucus layer (IML) and intestinal epithelial cells. Herein, we characterized interactions between the IML and PEP after degradation by the gut microbes. Our results showed that fermented P. eryngii polysaccharide (FPEP) can interact with intestinal mucus (IM), and this interaction can reduce the degree of molecular aggregation of polysaccharides. At the same time, the fermentation time of FPEP also affects the interaction between the two. SEM showed that the FPEP solution tended to aggregate into larger particles, while with the addition of IM, the FPEP molecules were dispersed. Particle size measurements unveil substantial differences in the fermented polysaccharides' particle size between the group with supplementary IM (0 hours of fermentation: 485.1 ± 11.3 nm) and the group without IM (0 hours of fermentation: 989.33 ± 21.3 nm). Remarkably, within the group with added IM, the particle size reached its maximum at 24 hours of fermentation (585.87 ± 42.83 nm). Additionally, turbidity assessments demonstrate that, during the 12-hour interaction period, the 24-hour fermented polysaccharides consistently exhibit the highest OD values, ranging between 0.57 and 0.61. This work investigates the interaction between FPEP and IM, predicting the adhesion of polysaccharides to IM. Meanwhile, this provides a theoretical basis for further studies on the absorption and transport pathways of PEP and provides a novel research viewpoint on intestinal digestion and absorption.

Study on the physicochemical properties and antioxidant activities of Flammulina velutipes polysaccharide under controllable ultrasonic degradation based on artificial neural network.

The polysaccharide fraction (FVP2) with molecular weight of 1525.09 kDa and intrinsic viscosity of 3.43 dL/g was isolated and purified from Flammulina velutipes (F. velutipes), and the ultrasonic degradation model of FVP2 was established to predict the molecular weight and intrinsic viscosity at the same time based on artificial neural network. FVP2U1 (1149.11 kDa, 1.78 dL/g), FVP2U2 (618.91 kDa, 1.19 dL/g) and FVP2U3 (597.35 kDa, 0.48 dL/g) with different molecular weights or viscosity were produced by this model to explore the effect of ultrasound on the physicochemical properties and antioxidant activity of FVP2. The results showed that ultrasonic treatment did not change the types of characteristic functional groups, monosaccharide composition and glycosidic bond of FVP2, but changed the chemical composition ratio and the degree of polymerization. Under ultrasonic treatment, the intrinsic viscosity of FVP2 still decreased significantly when the molecular weight did not decrease. Compared to other components subjected to ultrasonic degradation, FVP2U1 demonstrated higher molecular weight and viscoelasticity, while exhibiting lower antioxidant activity. In the case of no significant difference in molecular weight and monosaccharide composition, FVP2U3 with lower intrinsic viscosity has stronger hydration ability, higher crystallization index, lower viscoelasticity and stronger antioxidant capacity than FVP2U2.

Flammulina velutipes polysaccharides regulate lipid metabolism disorders in HFD-fed mice via bile acids metabolism.

Our recent study demonstrated that the dynamic changes of gut microbiota mediated by Flammulina velutipes polysaccharide (FVP) could effectively regulate the lipid metabolism in high fat diet-fed (HFD-fed) obese mice model. In this paper, further research was carried out by examining the bile acid (BAs) profiles, as well as the BAs metabolic pathways changes in obese mice. Furthermore, the regulatory effect of BAs on lipid metabolism was verified by 3 T3-L1 preadipocyte differentiation model. The FVP administration resulted in lower BAs content in plasma of obese mice. From the qRT-PCR analysis, FVP could relieve cholestasis in obese mice through altering the BAs metabolic pathways, changing the related genes expressions in mice liver and ileum. The cholic acid (CA), chenodeoxycholic acid (CDCA), hyodeoxycholic acid (HDCA) and ursodeoxycholic acid (UDCA) were selected in cell experiment which all reduced the intracellular triglyceride content and increased the expression of AMPKα1 in 3 T3-L1 adipocytes. Furthermore, CA and CDCA were found increased the expression of PPARα. In combination with our previous research, we further confirmed in this paper that the changes of BAs metabolism caused by FVP showed a positive effect on lipid metabolism, both in obese mice and 3 T3-L1 adipocytes.

Single-Molecule Dendritic MRI Nanoprobes Reveal the Size-Dependent Tumor Entrance.

The tumor entrance of drug delivery systems, including therapeutic proteins and nanomedicine, plays an essential role in affecting the treatment outcome. Nanoparticle size is a critical but contradictory factor in making a trade-off among blood circulation, tumor accumulation, and penetration. Here, this work designs a series of single-molecule gadolinium (Gd)-based magnetic resonance imaging (MRI) nanoprobes with well-defined sizes to precisely explore the size-dependent tumor entrance in vivo. The MRI nanoprobes obtained by divergent synthesis contain a core molecule of macrocyclic Gd(III)-chelate and different layers of dendritic lysine units, mimicking globular protein. This work finds that the r1 relaxivity and MR imaging signals increase with the nanoparticle size. The nanoprobe with a lower limit of critical size threshold ≈8.0 nm achieves superior tumor accumulation and penetration. These single-molecule MRI nanoprobes can be served to precisely examine the size-related nanoparticle-biological interactions.

Surface chemistry mediates the tumor entrance of nanoparticles probed using single-molecule dual-imaging nanodots.

The active transport of nanoparticles into solid tumors through transcytosis has been recognized as a promising way to enhance tumor accumulation and penetration, but the effect of the physicochemical properties of nanoparticles remains unclear. Herein, we develop a type of single-molecule dual imaging nanodot by divergent growth of perylenediimide (PDI)-dye-cored polylysine dendrimers and internal orthogonal conjugation of Gd(III)-based macrocyclic probes for fluorescence imaging and magnetic resonance imaging (MRI) of surface chemistry-dependent tumor entrance. The MRI and fluorescence imaging show that sixth-generation nanodots with acetylated (G6-Ac) and oligo ethylene glycol (G6-OEG) surfaces exhibit similar high tumor accumulation but different intratumor distribution. Cellular uptake and transport experiments suggest that G6-Ac nanodots have lower lysosomal entrapment (61% vs. 83%) and a higher exocytotic rate (47% vs. 29%) than G6-OEG. Therefore, G6-Ac is more likely to undergo intercellular transport through cell transcytosis, and is able to reach a tumor area distant from blood vessels, while G6-OEG mainly enters the tumor through enhanced permeability and retention (EPR) effect-based passive transport, and is not able to deliver to distant tumor areas. This study suggests that it is possible to boost the tumor entrance of nanoparticles by engineering surface chemistry for active transport.

Supramolecular metal-organic frameworks as host-guest nanoplatforms for versatile and customizable biomedical applications.

Molecular imaging of disease with multifunctional nanoparticles has improved specificity and sensitivity but also raises the complexity, potential toxicity, and cost. Here, we show a facile and degradable self-assembly ß-cyclodextrin metal-organic framework (ß-CD-MOF) nanoplatform for customizable multifunctional imaging. These ß-CD-MOF nanoparticles were obtained with favorable morphology and size by controlling the degradation time. The ß-CD-MOF were used as nanoplatforms for facile functionalization with adamantane (Ad)-modified probes through host-guest interactions between the surface ß-CD units and Ad molecules. We demonstrated the method's feasibility and capability by developing various contrast agents for multiple biomedical imaging, including fluorescence imaging, magnetic resonance imaging (MRI), and computed tomography (CT) imaging. The nanoprobes showed superior performance compared to the corresponding small molecular probes, including better physio-chemical properties (e.g., about 5 times of T1 relaxivity for MRI, 1.2 times of Hounsfield units for CT), improved pharmacokinetics, effective tissue imaging capability, and low safety concerns. These ß-CD-MOF-based nanoparticles are promising host-guest nanoplatforms for developing multifunctional and safe imaging probes. STATEMENT OF SIGNIFICANCE: Molecular imaging of disease with multifunctional nanoparticles has improved specificity and sensitivity but also raises the complexity, potential toxicity, and cost. Here, we introduce facile and degradable self-assembly ß-cyclodextrin metal-organic framework (ß-CD-MOF) nanoplatforms for customizable multifunctional imaging. The significance of this work includes: 1) This work reports the tailoring of MOFs nanoparticles with suitable sizes and shapes for biomedical applications through controllable morphological transition and degradation; 2) The ß-CD-MOF-based host-guest nanoplatforms are facile and feasible for developing multifunctional nanoparticular contrast agents for effective tissue imaging; 3) The nanoparticular contrast agents show low safety concerns with a long-term tissue deposition similar to the small molecular probes.

Magnetic ion-imprinted polyacrylonitrile-chitosan electro-spun nanofibrous membrane as recyclable adsorbent with selective heavy metal removal and antibacterial fouling in water treatment.

Water pollution has become one of the most concerned environmental issues on the worldwide scale. Due to the harmfulness of the heavy metal ions and microorganisms in wastewater, novel filtration membranes for water treatment are expected to simultaneously clear these pollutants. Herein, the electro-spun polyacrylonitrile (PAN) based magnetic ion-imprinted membrane (MIIM) were fabricated to achieve both selective removal of Pb(II) ions and excellent antibacterial efficiency. The competitive removal experiments showed that the MIIM displayed efficiently selective removal of Pb(II) (45.4 mg·g-1). Pseudo-second-order mode and Langmuir isotherm equation is well matched with the equilibrium adsorption. The MIIM showed sustained removal performance (~79.0 %) against Pb(II) ions after 7 adsorption-desorption cycles with negligible Fe ions loss of 7.3 %. Moreover, the MIIM exhibited excellent antibacterial properties that >90 % of E. coli and S. aureus were killed by the MIIM. In conclusion, the MIIM provides a novel technological platform for integration of multi-function with selective metal ions removal, excellent cycling reusability, and enhanced antibacterial fouling property, which can be potentially utilized as a promising adsorbent in actual treatment of polluted water.

Effects of Flammulina velutipes polysaccharides on gut microbiota composition and metabolism in vitro fermentation.

Flammulina velutipes polysaccharides (FVP) exhibit many biological activities, but the effects on gut microflora and metabolism were still unclear. Here, we explored the composition of FVP, their influence on human gut microflora composition and metabolites. FVP were used to vitro fermentation through human fecal inoculums. In addition, 16S rRNA sequencing were used to assess the effects of FVP on the gut microbiota. The metabolic profiles were investigated using untargeted metabolomics approaches in the LC-MS platform. The results showed that FVP was mainly consisted of glucose, mannose, xylose, fucose and galactose. FVP is shown to increase the relative abundances of Bifidobacteriaceae, as well as Bacteroidaceae and remarkably decrease the numbers of genera Lachnospiraceae coupled with Enterococcaceae. The differential metabolites were identified and mainly involved the metabolism of glycerophospholipid, linoleic acid and synthesis of unsaturated fatty acids. FVP may exhibit biological activity function by regulating gut microflora composition and metabolites. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01192-y.

Identification and preparation of selenium-containing peptides from selenium-enriched Pleurotus eryngii and their protective effect on lead-induced oxidative damage in NCTC1469 hepatocytes.

BACKGROUND: Lead (Pb) is a highly toxic and persistent substance that easily accumulates in living organisms, eliciting cellular toxicity and oxidative stress. Some selenium-containing proteins and peptides prepared from plant extracts are beneficial for protecting the body's health and resisting external disturbances. In the present study, selenium-containing peptide species were prepared from selenium-enriched Pleurotus eryngii protein hydrolysates and to evaluate the benefits of selenium-containing peptides on Pb-induced oxidative stress in NCTC1469 hepatocytes. RESULTS: Trypsin was selected as primary enzyme to hydrolyze the selenium-enriched protein (SPH). The optimal hydrolysis conditions were: hydrolysis time, 1.5 h; initial pH 8.0. The SPH was digested by trypsin and then purified by ultrafiltration, gel filtration chromatography and reversed-phase HPLC to obtain the selenium-containing peptides SPH-I-2. Furthermore, SPH-I-2 was analyzed and a number of total 12 selenium-containing peptides were identified by liquid chromatography-tandem mass spectroscopy. The NCTC1469 cell culture study showed that selenium-containing peptides were capable of reducing reactive oxygen species levels and regulating the Keap1/Nrf2 pathway by upregulating Nrf2, HO-1, GCLC, GCLM and NQO1 genes and downregulating Keap1 genes. Moreover, selenium-containing peptides were also able to suppress Pb-induced elevated levels of nitric oxide (NO), lactate dehydrogenase (LDH), malondialdehyde (MDA), increase antioxidant enzyme activity and alleviate cell apoptosis. CONCLUSION: The present study indicated that the selenium-containing peptides could protect cells from Pb2+ -induced oxidative stress. © 2023 Society of Chemical Industry.

Biosynthesis, behavior and fate of volatile organic sulfide in Lentinus edodes (Berk.) upon hot-air drying treatment.

This study elucidated the biosynthesis and changing behaviors of organic sulfide in shiitake mushrooms upon hot-air drying treatment. The changes of aw, moisture migration, contours of taste and flavor, organic sulfide, and 4 key enzyme activities were monitored throughout three drying procedures (CT/ST1/ST2). Results showed that drying rate was related to the moisture migration. Key enzymes of γ-GTase, ASFase and CS lyase were heat-resistant proteases, while C-Dase exhibited low thermal stability with the activity decreased during treatment. A total of 17 organic sulfides were identified and PLS analyses suggested 6 cyclic polysulfides were formed by C-Dase desulfurization, while 5 thioethers generation were related to the thermal cleavage of direct precursors (straight-chain di/tris/tetrasulfonyl esters) and Maillard reaction. These results indicated that ST2 drying procedures had a positive effect on the formation of cyclic polysulfides at the end of drying pried and the achievement of premium flavor qualities.