Molecular regulation of rapeseed protein for improving its techno-functional properties.

To improve the techno-functional properties of rapeseed protein (RP), this work tried to regulate the molecular structure of RP via inducing the co-assembly of RP with zein and whey protein (WP). The results showed that WP and zein mainly regulate the folding process of RP through hydrophobic and disulfide bonds, thereby altering the structural conformation and forming stable complex RP (CRP). WP addition not only increased the number of surface charges and hydrophilicity of proteins, but also decreased their sizes, improved the water solubility, as well as the availability of active groups. These changes significantly increased the foaming capacity (from 60 % to 147 %) and in vitro gastric digestion rate (from 10 % to 60 %) of CRP. Besides, WP also contributed to the formation of gels and the regulation of their textural profiles. Comparatively, zein improved the hydrophobicity of CRP and balanced degree of intermolecular forces, which effectively increased the emulsifying activity index of CRP from 22 m2/g to 90 m2/g. Zein decreased the hardness, springiness and water-holding capacity of gel, but increased its gumminess and chewiness. Overall, both WP and zein effectively changed the structural conformation of RP, and improved its techno-functional properties, which provides an effective strategy to modify protein.

Insights into digestibility, biological activity, and peptide profiling of flaxseed protein isolates treated by ultrasound coupled with alkali cycling.

This study aims to investigate the effects of ultrasound coupled with alkali cycling on the structural properties, digestion characteristics, biological activity, and peptide profiling of flaxseed protein isolates (FPI). The digestibility of FPI obtained by ultrasound coupled with pH 10/12 cycling (UFPI-10/12) (74.56 % and 79.12 %) was significantly higher than that of native FPI (64.40 %), and UFPI-10 showed higher hydrolysis degree (35.76 %) than FPI (30.65 %) after intestinal digestion. The combined treatment induced transition from α-helix to ß-sheet with an orderly structure. Large FPI aggregates broke down into small-sized FPI particles, which induced the increase of specific surface area of particles. This might expose more cutting sites and contact area with enzymes. Furthermore, UFPI-10 showed high antioxidant activity (29.18 %) and lipid-lowering activity (70.52 %). Peptide profiling revealed that UFPI-10 exhibited a higher proportion of 300-600 Da peptides and significantly higher abundance of antioxidant peptides than native FPI, which might promote its antioxidant activity. Those results suggest that the combined treatment is a promising modification method to improve the digestion characteristics and biological activity of FPI. This work provides new ideas for widespread use of FPI as an active stabilizer in food systems.

Understanding the mechanism for sodium tripolyphosphate in improving the physicochemical properties of low-moisture extrusion textured protein from rapeseed protein and soybean protein blends.

Our previous experiments found that rapeseed protein (RP) has applicability in low-moisture textured proteins. The amount of RP added is limited to <20 %, but the addition of 20 % RP still brings some negative effects. Therefore, in order to improve the quality of 20%RP textured protein, this experiment added different proportions of sodium tripolyphosphate (STPP) to improve the quality of the product, and studied the physical-chemical properties and molecular structure changes of the product to explore the possible modification mechanism. The STPP not only improved the expansion characteristics of extrudates, but also increased the brightness of the extrudates, the rehydration rate. In addition, STPP increased the specific mechanical energy during extrusion, decreased the material mass flow rate. Furthermore, STPP decreased the starch digestibility, increased the content of slow-digesting starch and resistant starch. STPP increased the degree of denaturation of extrudate proteins, the proportion of ß-sheets in the secondary structure of proteins, as well as the intermolecular hydrogen bonding interactions. The gelatinization degradation degree of starch molecules also decreased with the addition of STPP. STPP also increased the protein-starch interactions and enhanced the thermal stability of the extrudate. All these indicate that STPP can improve the physical-chemical properties of extrudate.

Optimization of ultrasonic conditions for improving the characteristics of corn starch-glycyrrhiza polysaccharide composite to prepare enhanced quality lycopene inclusion complex.

In this study, based on response surface optimization of ultrasound pre-treatment conditions for encapsulating lycopene, the corn starch-glycyrrhiza polysaccharide composite (US-CS-GP) was used to prepare a novel lycopene inclusion complex (US-CS-GP-Lyc). Ultrasound treatment (575 W, 25 kHz) at 35 °C for 25 min significantly enhanced the rheological and starch properties of US-CS-GP, facilitating the preparation of US-CS-GP-Lyc with an encapsulation efficiency of 76.12 ±â€¯1.76 %. In addition, the crystalline structure, thermal properties, and microstructure of the obtained lycopene inclusion complex were significantly improved and showed excellent antioxidant activity and storage stability. The US-CS-GP-Lyc exhibited a V-type crystal structure, enhanced lycopene loading capacity, and reduced crystalline regions due to increased amorphous regions, as well as superior thermal properties, including a lower maximum thermal decomposition rate and a higher maximum decomposition temperature. Furthermore, its smooth surface with dense pores provides enhanced space and protection for lycopene loading. Moreover, the US-CS-GP-Lyc displayed the highest DPPH scavenging rate (92.20 %) and enhanced stability under light and prolonged storage. These findings indicate that ultrasonic pretreatment can boost electrostatic forces and hydrogen bonding between corn starch and glycyrrhiza polysaccharide, enhance composite properties, and improve lycopene encapsulation, which may provide a scientific basis for the application of ultrasound technology in the refined processing of starch-polysaccharides composite products.

Improving the properties of whey protein isolate-zein nanogels with novel acidifiers: Re-dispersity, stability and quercetin bioavailability.

Low bioavailability of quercetin (Que) reduces its preclinical and clinical benefits. In order to improve Que bioavailability, a novel whey protein isolate (WPI)-zein nanogel was prepared by pH-driven self-assembly and heat-induced gelatinization. The results showed that hydrochloric acid can be substituted by both acetic acid and citric acid during the pH-driven process. After encapsulation, the bioavailability of Que in nanogels (composed of 70 % WPI) induced by different acidifiers increased to 19.89 % (citric acid), 21.65 % (hydrochloric acid) and 24.34 % (acetic acid), respectively. Comparatively, nanogels induced by acetic acid showed higher stability (pH and storage stability), re-dispersibility (75.62 %), Que bioavailability (24.34 %), and antioxidant capacity (36.78 % for DPPH scavenging rates). s improved performance of nanogels. In mechanism, acetic acid significantly balanced different intermolecular forces by weakening "acid-induced denaturation" effect. Moreover, the faster binding of Que and protein as well as higher protein molecular flexibility and randomness (higher ratio of random coil) was also observed in nanogels induced by acetic acid. All of these changes contributed to improve nanogels performances. Overall, WPI-zein nanogels induced by acetic acid might be a safe, efficiency and stable delivery system to improve the bioavailability of hydrophobic active ingredients.

Effect of subcritical water temperature on the chain conformation and immune activity of ginger polysaccharides.

In this study, the ginger polysaccharides extracted from hot water (HW-G) were modified with subcritical water (SW-G) to effectively regulate their immune activity, and the relationship between polysaccharide chain conformation and immune activity at different subcritical water temperatures was investigated. The results indicated that, compared with HW-G, the xylose and mannose were degraded at high temperatures. The molecular weight of ginger polysaccharide decreased from 1.083 × 106 g/mol to 3.113 × 105 g/mol after subcritical water modification (100-160 °C). The chain conformation transitioned from rigid rod chain to semi-rigid chain and eventually to random coil. The degree of relaxation of the polysaccharide chains showed a continuous increase trend. Additionally, ginger polysaccharide modified by subcritical water at 130 °C was found to promote the proliferation and phagocytosis of 264.7 cells more obviously and signally increase the secretion levels of NO, IL-6, TNF-α and IL-1ß. When the subcritical water temperature exceeds 130 °C, the activity of ginger polysaccharide begins to decline rapidly. These findings demonstrate a close correlation between polysaccharide chain conformation and immunomodulatory activity, confirming the feasibility of the subcritical water temperature effect as a means of immune activity regulation, which opens up a new approach to obtaining highly active polysaccharides.

Hypoxia induces mitochondrial protein lactylation to limit oxidative phosphorylation.

Oxidative phosphorylation (OXPHOS) consumes oxygen to produce ATP. However, the mechanism that balances OXPHOS activity and intracellular oxygen availability remains elusive. Here, we report that mitochondrial protein lactylation is induced by intracellular hypoxia to constrain OXPHOS. We show that mitochondrial alanyl-tRNA synthetase (AARS2) is a protein lysine lactyltransferase, whose proteasomal degradation is enhanced by proline 377 hydroxylation catalyzed by the oxygen-sensing hydroxylase PHD2. Hypoxia induces AARS2 accumulation to lactylate PDHA1 lysine 336 in the pyruvate dehydrogenase complex and carnitine palmitoyltransferase 2 (CPT2) lysine 457/8, inactivating both enzymes and inhibiting OXPHOS by limiting acetyl-CoA influx from pyruvate and fatty acid oxidation, respectively. PDHA1 and CPT2 lactylation can be reversed by SIRT3 to activate OXPHOS. In mouse muscle cells, lactylation is induced by lactate oxidation-induced intracellular hypoxia during exercise to constrain high-intensity endurance running exhaustion time, which can be increased or decreased by decreasing or increasing lactylation levels, respectively. Our results reveal that mitochondrial protein lactylation integrates intracellular hypoxia and lactate signals to regulate OXPHOS.

Effect of subcritical water temperature on the structure, antioxidant activity and immune activity of polysaccharides from Glycyrrhiza inflata Batalin.

In this study, the polysaccharide from Glycyrrhiza inflata Batalin extracted by hot water (HW-GP) was further physically modified with subcritical water to obtain novel polysaccharides (SW-GP). Comparative analysis was conducted to examine the disparities in conformation and bioactivity between HW-GP and SW-GP, aiming to precisely regulate the structure of the polysaccharides and enhance their bioactivity by controlling subcritical water temperature. The results showed that, compared with HW-GP, subcritical water modification (100-160 °C) not only significantly reduced the molecular weight of polysaccharides (from 5.586 × 105 g/mol to 1.484 × 105 g/mol), but also modulated the intermolecular interaction forces, which maintain the conformation of the polysaccharides, including electrostatic and hydrophobic interactions, thereby dynamically transforming the polysaccharide chain conformation from triple helix to random coil, and the strength of the chain conformation shifted from rigid to flexible. In addition, the modification of the SW-GP structure by subcritical water also enhanced its biological activity. SW-GP (140 °C) with low molecular weight and semi-rigid triple helix conformation showed the best scavenging effect on the DPPH, ABTS, and hydroxyl radicals, and exhibited excellent antioxidant activity. SW-GP (130 °C) with medium molecular weight and semi-rigid triple helix conformation significantly promoted the proliferation and phagocytosis of RAW264.7 cells, as well as increased the release levels of NO, TNF-α, IL-6, and IL-1ß, and the immunomodulatory activity was much higher than that of other polysaccharides. These findings confirmed the feasibility of using subcritical water temperature as a regulatory feature for the structure and bioactivity of glycyrrhiza polysaccharides, which may have reference significance for the modification of polysaccharides with heightened bioactivity.

A novel Sagittaria sagittifolia L. polysaccharides mitigate DSS-induced colitis via modulation of gut microbiota and MAPK/NF-κB signaling pathways.

Sagittaria sagittifolia L. polysaccharides possess anti-inflammatory, antioxidant, and immune-modulatory properties. In this study, we identified a novel S. sagittifolia L. polysaccharide, named PSSP-1, and evaluated its potential in alleviating dextran sulfate sodium (DSS)-induced colitis in a mouse model. The results demonstrated that administration of PSSP-1 at doses of 100, 200, and 400 mg/kg·bw significantly reduced the disease activity index (DAI) and suppressed the expression of inflammatory cytokines in UC mice. Furthermore, PSSP-1 treatment upregulated the expression levels of claudin-1, occludin, and ZO-1, and promoted the diversity and abundance of beneficial gut microbiota, including Lactobacillus and Candidatus_Saccharimonas, while reducing the levels of Bacteroidetes and Verrucomicrobiota. Particularly, the Lactobacillus_johnsonii species may play a potentially significant role in modulating colitis. Subsequently, there was a significant increase in the levels of short-chain fatty acids (SCFAs). Additionally, the correlation analyses revealed positive associations between PSSP-1 supplementation and Nitrosospira and Dialister, which are implicated in gut inflammation. Mechanistically, PSSP-1 intervention inhibited the protein phosphorylation of key molecules in the MAPK and NF-κB signaling pathways. Collectively, these findings suggest that PSSP-1 mitigates colitis symptoms by repairing the intestinal barrier, promoting microbial metabolism, and regulating the gut microbiota-MAPK/NF-κB signaling pathways.

Redesign of air/oil-water interface via physical fields coupled with pH shifting to improve the emulsification, foaming, and digestion properties of plant proteins.

The application of plant proteins in food systems is largely hindered by their poor foaming or emulsifying properties and low digestibility compared with animal proteins, especially due to the aggregate state with tightly folded structure, slowly adsorbing at the interfaces, generating films with lower mechanical properties, and exposing less cutting sites. Physical fields and pH shifting have certain synergistic effects to efficiently tune the structure and redesign the interfacial layer of plant proteins, further enhancing their foaming or emulsifying properties. The improvement mechanisms mainly include: i) Aggregated plant proteins are depolymerized to form small protein particles and flexible structure is more easily exposed by combination treatment; ii) Particles with appropriate surface properties are quickly adsorbed to the interfacial layer, and then unfolded and rearranged to generate a tightly packed stiff interfacial layer to enhance bubble and emulsion stability; and iii) The unfolding and rearrangement of protein structure at the interface may result in the exposure of more cutting sites of digestive enzymes. This review summarizes the latest research progress on the structural changes, interfacial behaviors, and digestion properties of plant proteins under combined treatment, and elucidates the future development of these modification technologies for plant proteins in the food industry.

Effects of slit dual-frequency ultrasound-assisted pulping on the structure, functional properties and antioxidant activity of Lycium barbarum proteins and in situ real-time monitoring process.

To improve the protein dissolution rate and the quality of fresh Lycium barbarum pulp (LBP), we optimized the slit dual-frequency ultrasound-assisted pulping process, explored the dissolution kinetics of Lycium barbarum protein (LBPr), and established a near-infrared spectroscopy in situ real-time monitoring model for LBPr dissolution through spectral information analysis and chemometric methods. The results showed that under optimal conditions (dual-frequency 28-33 kHz, 300 W, 31 min, 40 °C, interval ratio 5:2 s/s), ultrasonic treatment not only significantly increased LBPr dissolution rate (increased by 71.48 %, p < 0.05), improved other nutrient contents and color, but also reduced the protein particle size, changed the amino acid composition ratio and protein structure, and increased the surface hydrophobicity, zeta potential, and free sulfhydryl content of protein, as well as the antioxidant activity of LBPr. In addition, ultrasonication significantly improved the functional properties of the protein, including thermal stability, foaming, emulsification and oil absorption capacity. Furthermore, the real-time monitoring model of the dissolution process was able to quantitatively predict the dissolution rate of LBPr with good calibration and prediction performance (Rc = 0.9835, RMSECV = 2.174, Rp = 0.9841, RMSEP = 1.206). These findings indicated that dual-frequency ultrasound has great potential to improve the quality of LBP and may provide a theoretical basis for the establishment of an intelligent control system in the industrialized production of LBP and the functional development of LBPr.

Detection of Frog Virus 3 by Integrating RPA-CRISPR/Cas12a-SPM with Deep Learning.

A fast, easy-to-implement, highly sensitive, and point-of-care (POC) detection system for frog virus 3 (FV3) is proposed. Combining recombinase polymerase amplification (RPA) and CRISPR/Cas12a, a limit of detection (LoD) of 100 aM (60.2 copies/µL) is achieved by optimizing RPA primers and CRISPR RNAs (crRNAs). For POC detection, smartphone microscopy is implemented, and an LoD of 10 aM is achieved in 40 min. The proposed system detects four positive animal-derived samples with a quantitation cycle (Cq) value of quantitative PCR (qPCR) in the range of 13 to 32. In addition, deep learning models are deployed for binary classification (positive or negative samples) and multiclass classification (different concentrations of FV3 and negative samples), achieving 100 and 98.75% accuracy, respectively. Without temperature regulation and expensive equipment, the proposed RPA-CRISPR/Cas12a combined with smartphone readouts and artificial-intelligence-assisted classification showcases the great potential for FV3 detection, specifically POC detection of DNA virus.

Gut microbiota modulate distal symmetric polyneuropathy in patients with diabetes.

The pathogenic mechanisms underlying distal symmetric polyneuropathy (DSPN), a common neuropathy in patients with diabetes mellitus (DM), are not fully understood. Here, we discover that the gut microbiota from patients with DSPN can induce a phenotype exhibiting more severe peripheral neuropathy in db/db mice. In a randomized, double-blind, and placebo-controlled trial (ChiCTR1800017257), compared to 10 patients who received placebo, DSPN was significantly alleviated in the 22 patients who received fecal microbiota transplants from healthy donors, independent of glycemic control. The gut bacterial genomes that correlated with the Toronto Clinical Scoring System (TCSS) score were organized in two competing guilds. Increased guild 1, which had higher capacity in butyrate production, and decreased guild 2, which harbored more genes in synthetic pathway of endotoxin, were associated with improved gut barrier integrity and decreased proinflammatory cytokine levels. Moreover, matched enterotype between transplants and recipients showed better therapeutic efficacy with more enriched guild 1 and suppressed guild 2. Thus, changes in these two competing guilds may play a causative role in DSPN and have the potential for therapeutic targeting.

Study on the interaction and functional properties of Dolichos lablab L. protein-tea polyphenols complexes.

Tea polyphenols (TP) and plant proteins are significant materials in the food industry, the interactions between them are beneficial for their stability, functional properties, and biological activity. In this study, the mechanism and interaction between Dolichos lablab L. protein (DLP) obtained from nine treatments and three tea polyphenol monomers (EGCG, ECG, and EGC) were investigated. The results showed that the fluorescence of DLP was noticeably quenched and exhibited static quenching after the addition of polyphenols. DLP exhibited 1-2 binding sites for EGCG and ECG, but weakly binding to EGC (<1). The binding sites of DLP-TP were found to be in close proximity to the tyrosine residues, primarily interacting through hydrophobic interactions, van der Waals forces, and hydrogen bonds. The antioxidant capacity of DLP-TP compound was significantly improved after digestion. ECG showed a strong resistance to intestinal digestion. Compared with ECG (653.456 µg/mL), the content of free tea polyphenols of 20/40 kHz-ECG after digestion was 732.42 µg/mL. DLP-TP complexes significantly improved the storage stability, thermal stability, and bioaccessibility of tea polyphenols. The interaction between TP and DLP, as a protein-polyphenol complex, has great potential for application in preparing emulsion delivery systems due to their antioxidant activity and improved stability.

Slit dual-frequency ultrasound-assisted pulping of Lycium barbarum fresh fruit to improve the dissolution of polysaccharides and in situ real-time monitoring.

In this study, the slit dual-frequency ultrasound-assisted pulping of fresh Lycium barbarum fruit was optimized to improve the dissolution of polysaccharides. The microscopic mechanism of polysaccharide dissolution was explored through establishing polysaccharides dissolution kinetics model and visualizing the multi-physical fields during ultrasonic process, and an in situ real-time monitoring model was established by the relationship between the chemical value and spectral information collected by near-infrared spectroscopy. The results showed that, under optimal conditions, treatment with ultrasound (28-33 kHz, 250 W, 30 min) not only significantly promoted the dissolution rate of polysaccharides in Lycium barbarum pulp (LBPPs, increased by 43.64 %, p < 0.01), reduced its molecular weight, but also improved the arabinose molar ratio, the uniformity of polysaccharide particles, and the antioxidant activity of LBPPs. Correlation analysis indicated that ultrasonic treatment is closely related to LBPPs content, particle size and scavenging capacity against superoxide anion radicals (ptotal sugar content < 0.01, pparticle size < 0.05 and psuperoxide anion scavenging < 0.05). Moreover, the in situ real-time monitoring model for the pulping process could quantitatively predict LBPPs dissolution rate and its superoxide anion radical scavenging capacity with good calibration and prediction performance (Rc = 0.9841, RMSECV = 0.0873, Rp = 0.9772, RMSEP = 0.0530; Rc = 0.9874, RMSECV = 0.1246, Rp = 0.9868, RMSEP = 0.0665). These results indicated that slit dual-frequency ultrasound has great potential in improving the quality of Lycium barbarum pulp, which may provide theoretical support for the industrial development of intelligent systems for polysaccharides preparation.

Blocking TRAIL-DR5 signaling pathway with soluble death receptor 5 fusion protein mitigates radiation-induced injury.

The increasing application of nuclear technology, the high fatality of acute radiation syndrome (ARS) and its complex mechanism make ARS a global difficulty that requires urgent attention. Here we reported that the death receptor 5 (DR5), as well as its ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were both significantly upregulated after irradiation in mice with 6 Gy γ-ray single radiation. And by intravenously administrated with soluble DR5 fusion protein (sDR5-Fc), the competitive antagonist of DR5, the excessive apoptosis in the radiation-sensitive tissues such as spleen and thymus were significantly inhibited and the radiation-induced damage of spleen and thymus were mitigated, while the expression of apoptosis-inhibiting proteins such as Bcl-2 was also significantly upregulated. The biochemical indicators such as serum ALP, AST, ALT, TBIL, K, and Cl levels that affected by radiation, were improved by sDR5-Fc administration. sDR5-Fc can also regulate the number of immune cells and reduce blood cell death. For in vitro studies, it had been found that sDR5-Fc effectively inhibited apoptosis of human small intestinal mucosal epithelial cells and IEC-6 cells using flow cytometry. Finally, survival studies showed that mice administrated with sDR5-Fc after 9 Gy γ-ray single whole body radiation effectively increased the 30-day survival and was in a significant dose-dependent manner. Overall, the findings revealed that DR5/TRAIL-mediated apoptosis pathway had played important roles in the injury of ARS mice, and DR5 probably be a potential target for ARS therapeutics. And the DR5 apoptosis antagonist, sDR5 fusion protein, probably is a promising anti-ARS drug candidate which deserves further investigation.

Ultrasound treatments improve germinability of soybean seeds: The key role of working frequency.

In this paper, the effects of ultrasound with different frequency modes on the sprouting rate, sprouting vigor, metabolism-related enzyme activity and late nutrient accumulation in soybean were investigated, and the mechanism of dual-frequency ultrasound promoting bean sprout development was explored. The results showed that, compared with control, the sprouting time was shortened by 24 h after dual-frequency ultrasound treatment (20/60 kHz), and the longest shoot was 7.82 cm at 96 h. Meanwhile, ultrasonic treatment significantly enhanced the activities of protease, amylase, lipase and peroxidase (p < 0.05), particularly the phenylalanine ammonia-lyase increased by 20.50%, which not only accelerated the seed metabolism, but also led to the accumulation of phenolics (p < 0.05), as well as more potent antioxidant activity at later stages of sprouting. In addition, the seed coat exhibited remarkable cracks and holes after ultrasonication, resulting in accelerated water absorption. Moreover, the immobilized water in seeds increased significantly, which was beneficial to seed metabolism and later sprouting. These findings confirmed that dual-frequency ultrasound pretreatment has a great potential to be used for seed sprouting and promoting the accumulation of nutrients in bean sprouts by accelerating water absorption and increasing enzyme activity.

A high efficiency CO2 concentration interval optimization method for lettuce growth.

The decline in carbon fertilization effects has shifted scientific focus toward the efficient and suitable regulation of CO2 concentration ([CO2]) for plant growth. In this study, the rapid A/CO2 response curve (RAC) data of lettuce were analyzed statistically under nine photosynthetic photon flux densities (PPFDs) and four temperatures. An efficient CO2 supplementation interval acquisition method based on the frequency distribution characteristics of RACs was proposed. The characteristic subsections of jumping were obtained depending on the frequency distribution of RACs. The cumulative contribution rate (CCR) of the characteristic subsections were >97 %, which showed the efficiency of the method. Additionally, U-chord curvature theory was used to simultaneously obtain the optimal regulated [CO2] for the same RAC curves, and the results showed that the [CO2] obtained by U-chord length were all within the interval obtained by the method, which proved the rationality of the method. The [CO2] interval supplement improved the daily CO2 exchange rate by 20.27 % and 21.64 % at 150 and 200 µmol·m-2·s-1, and increased the lettuce fresh biomass by 26.78 % at 150 µmol·m-2·s-1. Based on the interval of [CO2] efficient utilization regulation at various temperatures and PPFDs, a genetic algorithm-support vector regression model was built with R2 of the model was >0.84 and the root mean square error was <35.2256 µmol·mol-1. In conclusion, the [CO2] interval obtained by this method has a positive effect on lettuce growth. This work provides a new method for obtaining high-efficiency supplementary concentration of CO2 during the growth of lettuce.

Purse-string contraction guides mechanical gradient-dictated heterogeneous migration of epithelial monolayer.

Mechanical heterogeneity has been recognized as an important role in mediating collective cell migration, yet the related mechanism has not been elucidated. Herein, we fabricate heterogeneous stiffness gradients by leveraging microelastically-patterned hydrogels with varying periodic distance. We observe that a decrease in the periodic distance of the mechanical heterogeneity is accompanied by an overall increase in the velocity and directionality of the migrating monolayer. Moreover, inhibition of ROCK- and myosin ⅡA- but not Rac1-mediated contraction reduces monolayer migration on the mechanically heterogeneous substrates. Furthermore, we find that F-actin and myosin ⅡA form purse-string at the leading edge on the mechanically heterogeneous substrates. Together, these findings not only show that the orientational cell-cell contraction promotes collective cell migration under the mechanical heterogeneity, but also demonstrate that the mechanosensation arising from large-scale cell-cell interactions through purse-string formation mediated cell-cell orientational contraction can feed back to regulate the reorganization of epithelial tissues. STATEMENT OF SIGNIFICANCE: By detecting the links between heterogenous rigidity and collective cell migration behavior at the molecular level, we reveal that collective cell migration in the mechanical heterogeneity is driven by ROCK- and myosin-ⅡA-dependent cytoskeletal tension. We confirm that cytoskeletal tension across the epithelial tissue is holistically linked through F-actin and myosin-ⅡA, which cooperate to form purse-string structures for modulating collective tissue behavior on the exogenous matrix with mechanical heterogeneity. Mechanical heterogeneity initiates tissue growth, remodelling, and morphogenesis by orientating cell contractility. Therefore, tensional homeostasis across large-scale cell interactions appears to be necessary and sufficient to trigger collective tissue behavior. Overall, these findings shed light on the role of mechanical heterogeneity in tissue microenvironment for reorganization and morphogenesis.

Recent progress of Lycium barbarum polysaccharides on intestinal microbiota, microbial metabolites and health: a review.

Intestinal microbiota is symbiotically associated with host health, learning about the characteristics of microbiota and the factors that modulate it could assist in developing strategies to promote human health and prevent diseases. Polysaccharides from Lycium barbarum (LBPs) are found beneficial for enhancing the activity of gut microbiota, as a potential prebiotic, which not only participates in improving body immunity, obesity, hyperlipidemia and systemic inflammation induced by oxidative stress, but also plays a magnificent role in regulating intestinal microenvironment and improving host health and target intestinal effects via its biological activities, as well as gut microbiota and metabolites. To highlight the internal relationship between intestinal microbiota and LBPs, this review focuses on the latest advances in LBPs on the intestinal microbiota, metabolites, immune regulation, intestinal barrier protection, microbiota-gut-brain axis and host health. Moreover, the preparation, structure, bioactivity and modification of LBPs were also discussed. This review may offer new perspective on LBPs improving health of gut and host via intestinal microbiota, and provide useful guidelines for the application of LBPs in the food industry.