Competitive and synergic evolution of the water-food-ecology system: A case study of the Beijing-Tianjin-Hebei region, China.

A vital approach to attaining sustainable development lies in the in-depth examination of both competition and synergy between these subsystems from a water-food-ecology (WFE) system perspective, while previous or existing studies have limitations in to quantitative characterize and evaluation the cooperative and competitive relationships between different systems. In this study, an evaluation indicator system is constructed from the two dimensions of resources and efficiency, and the WFE synergic development capacity (WFE-SDC) is proposed by integrating the order degree of the coupled system, enables a multidimensional and comprehensive quantitative assessment of the sustainable development of the WFE system. Then a synergic evolution model is constructed to explore the competitive and synergic evolution of the WFE system in the Beijing-Tianjin-Hebei region. The following key insights were obtained: (1) The WFE-SDC (range of 0-1) shows a fluctuating increase, indicating a shift from mild dysfunctional recession to intermediate synergic development (0.24 to 0.72). (2) Principal factors impeding WFE-SDC encompass diversion water, ecology water consumption, grain demand, reclaimed water consumption, and outbound water, both come from resource dimension, with a combined impediment degree of over 46 %, and the improvement of efficiency dimension may improve the WFE-SDC. (3) The water subsystem acts as a driving force for synergic development, fostering cooperation within the food and ecology subsystems, although they mainly operate in a competitive state. (4) Within the WFE system, Beijing, Tianjin, and Hebei exhibited mutual cooperation and significantly contributed to one another's development. Beijing has played a pivotal role in the progress of both Tianjin and Hebei. This study offers valuable insights for the formulation of policies and the application of technical approaches for the sustainable development of the WFE system in relevant regions.

Genome-wide association mapping for yield-related traits in soybean (Glycine max) under well-watered and drought-stressed conditions.

Soybean (Glycine max) productivity is significantly reduced by drought stress. Breeders are aiming to improve soybean grain yields both under well-watered (WW) and drought-stressed (DS) conditions, however, little is known about the genetic architecture of yield-related traits. Here, a panel of 188 soybean germplasm was used in a genome wide association study (GWAS) to identify single nucleotide polymorphism (SNP) markers linked to yield-related traits including pod number per plant (PN), biomass per plant (BM) and seed weight per plant (SW). The SLAF-seq genotyping was conducted on the population and three phenotype traits were examined in WW and DS conditions in four environments. Based on best linear unbiased prediction (BLUP) data and individual environmental analyses, 39 SNPs were significantly associated with three soybean traits under two conditions, which were tagged to 26 genomic regions by linkage disequilibrium (LD) analysis. Of these, six QTLs qPN-WW19.1, qPN-DS8.8, qBM-WW1, qBM-DS17.4, qSW-WW4 and qSW-DS8 were identified controlling PN, BM and SW of soybean. There were larger proportions of favorable haplotypes for locus qPN-WW19.1 and qSW-WW4 rather than qBM-WW1, qBM-DS17.4, qPN-DS8.8 and qSW-DS8 in both landraces and improved cultivars. In addition, several putative candidate genes such as Glyma.19G211300, Glyma.17G057100 and Glyma.04G124800, encoding E3 ubiquitin-protein ligase BAH1, WRKY transcription factor 11 and protein zinc induced facilitator-like 1, respectively, were predicted. We propose that the further exploration of these locus will facilitate accelerating breeding for high-yield soybean cultivars.

Dry deposition effect of urban green spaces on ambient particulate matter pollution in China.

Particulate matter (PM) is a major source of urban air pollution that poses a serious threat to the environment and human health. This study quantified the dry deposition effect of PM2.5 and PM10 on vegetation using a mathematical model to overcome the limitations of traditional site-scale research. Additionally, multi-source satellite remote sensing products were combined to form a raster dataset to estimate the effect of dry deposition on PM2.5 and PM10 in China's urban green spaces from 2000 to 2020. The spatial and temporal changes in the long-term series were analyzed, and the influence of environmental factors on dry deposition was analyzed in combination with wavelet changes. The experimental results showed that: 1) from 2000 to 2020, the dry deposition effect of PM2.5 and PM10 on vegetation showed an initial increasing and then decreasing trend caused by the sudden drop in atmospheric pollutant particle concentration driven by local policies; 2) broad-leaved forests provided the main dry deposition effects in urban spaces, accounting for 89.22 %, indicating a need to increase the density of these forest types in urban development planning to improve air quality; and 3) PM2.5, PM10, and environmental impact factors have time-frequency scale coherences, and the coherence between PM2.5 reduction and these factors is more complex than that of PM10, with precipitation being the best variable to explain the change in PM2.5 and PM10. These findings are important for the prevention and control of urban air pollution, regional planning of green spaces, and sustainable development of cities.

Reversible cross-linking of gelatin by a disulphide-containing bis-succinimide for tunable degradation and release.

Generally, gelatin was irreversibly cross-linked by chemical reagents to improve its water-resistance. However, few chemical reagents meet both the requirements of high cross-inking efficiency and tunable degradation. Here a reversible cross-linker, disulphide-containing bis-succinimide, was synthesized and used to control the cross-linking and degradation of edible gelatin film. Mixture of the gelatin and cross-linker for 120 min generated gelatin films that could preserve their morphology in 37 ℃ warm water for above 40 days. The gelatin film changed its microstructure from net to tightness after the cross-linking, thus facilitating the embedding of the targeted molecule into the gelatin material. The degradation of the cross-linked gelatin film and the release of its inclusion could be controlled by biocompatible glutathione. This work provides a good method for preparing modified gelatin with promising water-resistance, good biocompatibility, and tunable degradation for food/biomedical engineering applications.

Bridge-DNA synthesis triggered by an allosteric aptamer for the colorimetric detection of pathogenic bacteria.

Rapid and sensitive quantification of pathogenic bacteria is highly desired for environmental health supervision and food safety control. Yet, the amplification and detection of bacteria with a concentration lower than 102 cfu mL-1 remains a great challenge. Here, we combined an allosteric aptamer (AAP) with a gold nanoparticle (AuNP) for assembling a bridge-DNA synthesis system (named as AuNP-BDS) to amplify the bacterial signals. The AAP and its paired primer (PP) were covalently linked to two different AuNPs, respectively: one named as AAP-AuNP and the other PP-AuNP. Upon recognition of the antigen from the pathogenic bacteria, AAP alters its conformation to initiate DNA synthesis on the AuNP surface. The DNA products from AAP-AuNP and PP-AuNP form bridges to each other through base pairing, resulting in the aggregation and colorimetric response of the AuNPs. By using E. coli O157:H7 as an example, the AuNP-BDS could quantify pathogenic bacteria in water with a concentration as low as 10 cfu mL-1 within 60 min and without any enrichment. The colorimetric response values of AuNP-BDS were found to be linearly related to the bacterial concentrations in the range of 10 to 103 cfu mL-1. Good practicability of the AuNP-BDS in quantifying E. coli O157:H7 from tap water, juices, and milks was demonstrated. The AuNP-BDS could be exploited to facilitate the rapid and sensitive quantification of pathogenic bacteria for food safety control.

An anti-bacterial porous shape memory self-adaptive stiffened polymer for alveolar bone regeneration after tooth extraction.

The regeneration of alveolar bone after tooth extraction is critical for the placement of dental implants. Developing a rigid porous scaffold with defect shape adaptability is of great importance but challenging for alveolar bone regeneration. Herein, we design and synthesize a biocompatible poly(l-glutamic acid)-g-poly(ε-caprolactone) (PLGA-g-PCL) porous shape memory (SM) polymer. The PLGA-g-PCL is then copolymerized with acryloyl chloride grafted poly(ω-pentadecalactone) (PPDLDA) having a higher phase transition temperature than shape recovery temperature to maintain stiffness after shape recovery to resist chewing force. The hybrid polydopamine/silver/hydroxyapatite (PDA/Ag/HA) is coated to the surface of (PLGA-g-PCL)-PPDL scaffold to afford the anti-bacterial activity. The porous SM scaffold can be deformed into a compact size and administered into the socket cavity in a minimally invasive mode, and recover its original shape with a high stiffness at body temperature, fitting well in the socket defect. The SM scaffold exhibits robust antibacterial activity against Staphylococcus aureus (S. aureus). The porous microstructure and cytocompatibility of PLGA allow for the ingrowth and proliferation of stem cells, thus facilitating osteogenic differentiation. The micro-CT and histological analyses demonstrate that the scaffold boosts efficient new bone regeneration in the socket of rabbit mandibular first premolar. This porous shape memory self-adaptive stiffened polymer opens up a new avenue for alveolar bone regeneration.

The synergism between self-activated and impurity-related emissions of LiCa3ZnV3O12: lattice distortion, energy transfer and temperature sensing effect.

Some of the metal vanadates have special self-activated luminescence. In order to further enrich its luminous color, luminescent impurity ions can be introduced into its lattice. The interaction between the self-activated emission and the impurity-related emission remains to be studied. In this work, the synergism between the two kinds of emission in LiCa3ZnV3O12 was explored from these three aspects: lattice distortion, energy transfer and temperature effect. Eu3+ ions replace Ca2+ ions in the lattice of LiCa3ZnV3O12, leading to a lattice contraction of the LCZV host, which depresses the self-activating emission around 500 nm. The characteristic linear emissions of Eu3+ ions are also observed benefiting from the energy transfer from [VO4]3- to Eu3+. Since the temperature quenching effect is more sensitive for the self-activated emission than that for the Eu3+-related ones, the phosphor can be applied as a luminescent temperature sensor, with the absolute and relative temperature sensitivities of 0.012 K-1 and 1.56% K-1, respectively.

On-bead DNA synthesis triggered by allosteric probe for detection of carcinoembryonic antigen.

Sensitive quantification of protein biomarkers is highly desired for clinical diagnosis and treatment. Yet, unlike DNA/RNA which can be greatly amplified by PCR/RT-PCR, the amplification and detection of trace amount of proteins remain a great challenge. Here, we combined allosteric probe (AP) with magnetic bead (MB) for assembling an on-bead DNA synthesis system (named as APMB) to amplify protein signals. The AP is designed and conjugated onto the MB, enabling the protein biomarker to be separated and enriched. Once recognizing the biomarker, the AP alters its conformation to initiate DNA synthesis on beads for primary signal amplification. During the DNA synthesis, biotin-dATPs are incorporated into the newly synthesized DNA strands. Then, the biotin-labeled DNA specifically captures streptavidin (STR)-conjugated horseradish peroxidase (HRP), which is used to catalyze a colorimetric reaction for secondary signal amplification. By using carcinoembryonic antigen (CEA) as a protein model, the APMB can quantify protein biomarkers of as low as 0.01 ng/mL. The response values measured by APMB are linearly related to the protein concentrations in the range 0.05 to 20 ng/mL. Clinical examination demonstrated good practicability of the APMB in quantifying serum protein biomarker. The on-bead DNA synthesis could be exploited to improve protein signal amplification, thus facilitating protein biomarker detection of low abundance for early diagnosis.

A novel ecohydrological model by capturing variations in climate change and vegetation coverage in a semi-arid region of China.

Variations in vegetation are influenced by regional climate regimes and, in turn, control the water balance behavior in water-limited regions. Owing to its role in ecohydrological processes, vegetation is an essential link in modeling the relationships among climate conditions, vegetation patterns, and dynamic water balance behavior. However, previous ecohydrological models have been empirical and complex, without physically significant parameters. Here, we propose a novel ecohydrological model (a Budyko model-coupled vegetation model) that combines the impacts of climate change and vegetation variations, featuring simple and deterministic parameters. In addition to accounting for the fundamental water balance model and its factors, mean precipitation, potential evapotranspiration, runoff, and variations in water storage (δS), the model showed better performance when incorporating δS (RMSE = 2.72 mm yr-1) and its parameter ε -, which is mechanically and quantitively subject to the vegetation coverage (R2 = 0.95, p < 0.01). This was estimated as a function of vegetation potential canopy conductance, mean rainstorm depth, mean time between storms, and potential rate of evapotranspiration in a semi-arid watershed with impulsive precipitation in China (R2 = 0.80, p < 0.01). The model also found that vegetation growth was mainly controlled by soil water content and decoupled the impact of the total amount of precipitation on vegetation in the northeastern area of the watershed. Hence, our method presents a new tool for building an ecohydrological model that includes deterministic parameters of mechanical significance.

Ultrahigh Charge Separation Achieved by Selective Growth of Bi4O5I2 Nanoplates on Electron-Accumulating Facets of Bi5O7I Nanobelts.

Ultrahigh charge separation was observed in Bi4O5I2/Bi5O7I two-dimensional (2D)/one-dimensional (1D) hierarchical structures (HSs) constructed by selective growth of 2D monocrystalline Bi4O5I2 nanoplates on the electron-accumulating (100) facet of 1D monocrystalline Bi5O7I nanobelts. In addition to the presence of type-II heterojunction between Bi4O5I2 and Bi5O7I elementary entities in 2D/1D HSs, the type-II (100)/(001) surface heterojunction in Bi5O7I nanobelt substrates was also confirmed by means of density functional theory (DFT) calculations and selective photoreduction/oxidation deposition experiments. The synergistic effect of two kinds of heterojunctions in Bi4O5I2/Bi5O7I 2D/1D HSs endowed them with ultrahigh charge carrier separation and transfer characteristics. In contrast with the control sample (BB40-C) constructed by growing Bi4O5I2 nanoplates on whole four sides of Bi5O7I nanobelts, Bi4O5I2/Bi5O7I 2D/1D HSs demonstrated significantly enhanced charge transfer between Bi5O7I nanobelt substrates and Bi4O5I2 nanoplates, owing to respective electron and hole accumulations on (100) and (001) facets of Bi5O7I substrates caused by (100)/(001) surface heterojunction. The enhanced separation behavior was successfully verified by steady/transient-state photoluminescence, electrochemical techniques, and photocatalytic degradation experiments. Based on the above effective charge separation of Bi4O5I2/Bi5O7I 2D/1D HSs as well as the routine advantages for 2D/1D HSs, such as the excellent charge transport in monocrystalline elementary entities, much higher specific surface area, and enhanced light absorption by multiple reflections, the optimal BB40 HSs demonstrated ultrahigh photocatalytic performance than the control samples, whose apparent rates for Rhodamine B [or tetracycline hydrochloride (TC)] degradation were 7.1 (2.9 for TC), 10.3 (4.7 for TC), and 2.2 (1.7 for TC) times those of pristine Bi5O7I nanobelts, Bi4O5I2 nanoplates, and BB40-C, respectively. It is hoped that this crystal facet selection during the heterostructure construction in this work could provide a new strategy or some enlightenment for the exploration of highly active 2D/1D HSs or other-dimensional heterostructure nanomaterials applied in the fields of photocatalysts, solar cells, sensors, and others.

HDAC5 promotes intestinal sepsis via the Ghrelin/E2F1/NF-κB axis.

In the current study, we sought to determine the roles of histone deacetylase 5 (HDAC5) on the promotion of intestinal sepsis in a mouse model. Dual luciferase reporter gene assay was used to determine the binding relationship between HDAC5 and Ghrelin. Cecal ligation and puncture (CLP) was used as an animal model of intestinal sepsis. The roles of HDAC5 on intestinal sepsis were determined by HDAC5 knockdown, overexpression, and inhibitor (LMK-235) in vivo. Mice intestinal permeability and intestinal epithelial damage were evaluated, and HE staining was used to evaluate the intestinal mucosal injury index. Lipopolysaccharide (LPS)-treated intestinal-derived macrophages served as a cell model of sepsis, followed by the loss-of-function and gain-of-function assays. ELISA was used to determine the levels of inflammatory factors, and TUNEL staining was used to detect intestinal cell apoptosis. HDAC5 was upregulated in the intestine of sepsis patients. This increased HDAC5 expression was positively correlated with the expression of inflammatory factors TNF-α, IL-1ß, IL-6, and HMGB1, as well as the intestinal dysfunction-related factors IFABP. In sepsis mice, the expression of inflammatory factors was reduced by HDAC5 knockdown. HDAC5 knockdown also improved survival, morphology of intestinal tissue, intestinal permeability, and epithelial damage. Ghrelin was bound and inhibited by HDAC5, but E2F1 expression was increased by Ghrelin overexpression, leading to inhibition of the NF-κB pathway. Ghrelin and E2F1 expression were increased by the treatment with HDAC5 inhibitor LMK-235, which inhibited the NF-κB pathway to improve intestinal dysfunction in the sepsis model. In conclusion, HDAC5 inhibits Ghrelin to reduce E2F1 and thus activate the NF-κB pathway, thereby promoting intestinal sepsis.

Ghrelin Alleviates Intestinal Dysfunction in Sepsis Through the KLF4/MMP2 Regulatory Axis by Activating SIRT1.

Intestinal barrier dysfunction is an important contributor to morbidity caused by sepsis. This study investigates the molecular mechanism by which Ghrelin affects intestinal dysfunction in rat model of sepsis. A rat model of sepsis was established by cecal ligation and puncture (CLP), revealing that Ghrelin was downregulated when sepsis occurs. Increases in the levels of inflammatory factors tumor necrosis factor α (TNF-α), interleukin-1 (IL-1ß), IL-6, gastrin, γ-H2AX and 8-OHdG was also detected in this model system, as was an overall increase in oxidative stress. Introduction of exogenous Ghrelin inhibited these increases in inflammatory response and oxidative stress, leading to a reduction of overall sepsis-induced intestinal dysfunction. Ghrelin was then shown to activate SIRT1 expression in vitro, while SIRT1 was found to co-express with KLF4, which in turn was predicted to bind to matrix metalloproteinase 2 (MMP2) promoter. Finally, gain- and loss-of-function experiment demonstrated that SIRT1 upregulated the expression of KLF4 to downregulate MMP2. Collectively, Ghrelin inhibits the oxidative stress and intestinal dysfunction to attenuate sepsis by activating SIRT1 and regulating a KLF4/MMP2 regulatory axis.

Using a safe and effective fixative to improve the immunofluorescence staining of bacteria.

The emerging and development of green chemistry has once again drawn the researchers' attention to eliminating the use and generation of hazardous materials. Here we report the use of a safe and effective fixative, chlorine dioxide (ClO2), instead of traditional hazardous fixatives for the cross-linking of cellular proteins to improve immunofluorescence staining of bacteria. The concentration of ClO2needed for 100% fixation is 50µg ml-1, which is much lower than that of traditional fixatives (1000-10000µg ml-1). The ClO2mediated cross-linking can preserve the integrity of bacterial cells and prevent cell loss through lysis. Meanwhile, lysozyme can permeabilize the bacterial cells, allowing the labelled antibodies to diffuse to their intracellular target molecules. By usingE. coliO157:H7/RP4 as a gram-negative bacteria model, immunofluorescence staining assays for both intracellular protein and surface polysaccharide were carried out to investigate the effect of ClO2fixation on the staining. The results demonstrated that ClO2fixation could prevent the target antigens from cracking off the bacteria without damage on the interaction between the antibodies and antigens (either for polysaccharide or protein). As a safe and effective fixative, ClO2has potential practical applications in immunofluorescence staining and fluorescencein situhybridization for single bacteria/cell analysis.

Engineering Resistance to Bacterial Blight and Bacterial Leaf Streak in Rice.

BACKGROUND: Xanthomonas oryzae (Xo) is one of the important pathogenic bacterial groups affecting rice production. Its pathovars Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) cause bacterial blight and bacterial leaf streak in rice, respectively. Xo infects host plants by relying mainly on its transcription activator-like effectors (TALEs) that bind to host DNA targets, named effector binding elements (EBEs), and induce the expression of downstream major susceptibility genes. Blocking TALE binding to EBE could increase rice resistance to the corresponding Xo. FINDINGS: We used CRISPR/Cas9 to edit the EBEs of three major susceptibility genes (OsSWEET11, OsSWEET14 and OsSULTR3;6) in the rice varieties Guihong 1 and Zhonghua 11. Both varieties have a natural one-base mutation in the EBE of another major susceptibility gene (OsSWEET13) which is not induced by the corresponding TALE. Two rice lines GT0105 (from Guihong 1) and ZT0918 (from Zhonghua 11) with target mutations and transgene-free were obtained and showed significantly enhanced resistance to the tested strains of Xoo and Xoc. Furthermore, under simulated field conditions, the morphology and other agronomic traits of GT0105 and ZT0918 were basically the same as those of the wild types. CONCLUSIONS: In this study, we first reported that the engineering rice lines obtained by editing the promoters of susceptibility genes are resistant to Xoo and Xoc, and their original agronomic traits are not affected.

Physicochemical and Microbiological Properties of Synbiotic Yogurt Made with Probiotic Yeast Saccharomyces boulardii in Combination with Inulin.

Saccharomyces boulardii is a unique species of yeast previously characterized as a probiotic strain (CNCM I-745) among a few probiotic yeasts reported to date. Inulin is one of the most common prebiotics that exhibit twisted hydrocolloidal properties in dairy products. The present study was designed to develop a synbiotic yogurt by incorporation of S. boulardii and inulin at 1%, 1.5%, and 2% (w/v), comparing with the probiotic and control plain yogurts. Microrheological, microstructural, microbiological, sensory properties, and volatile compounds of the yogurt samples were evaluated. Microrheological analysis showed that addition of inulin to yogurt slightly reduced the values of G' and G″, while solid-liquid balance (SLB) values confirmed more solid properties of the synbiotic yogurt (0.582~0.595) than the plain yogurt (0.503~0.518). A total of 18 volatile compounds were identified in the synbiotic yogurt, while only five and six compounds were identified in plain and probiotic yogurts, respectively. Physiochemical parameters such as pH, acidity, and protein content were in the normal range (as with the control), while fat content in the synbiotic yogurt decreased significantly. Addition of 1% inulin not only reduced syneresis but also maintained viability of S. boulardii after 28 days of storage. Microstructural and microrheological studies confirmed the dense, compressed, homogeneous structure of the synbiotic yogurt. Thus, addition of inulin improved the textural and sensory properties of the synbiotic yogurt, as well as survival of S. boulardii with viable count above 6.0 log CFU/g in yogurt, as generally required for probiotics. Therefore, novel synbiotic yogurt with desirable quality was developed as an effective carrier for delivery of the probiotic yeast exerting its beneficial health effects.

Effect of chemical aging of Alternanthera philoxeroides-derived biochar on the adsorption of Pb(II).

In this study, biochar was prepared from Alternanthera philoxeroides (AP) under O2-limited condition at 350 °C (LB) and 650 °C (HB) and treated with aging by HNO3/H2SO4 oxidation. Structural changes of the biochar after aging treatment and the treatment's effect on Pb(II) absorption were explored. The results showed that oxygen-containing functional groups, aromatic structure and surface area of the biochar increased after the aging treatment. However, the integrity of the tubular structure was broken into fragments. The adsorption process of Pb(II) was in accordance with the pseudo-second-order kinetic model and fitted by the Langmuir model. With the increase of pH, the adsorption capacities of Pb(II) increased gradually, and the adsorption effect was best at pH 5. The aged HB presented a decrease of the carboxyl group, which caused less adsorption capacity of Pb(II) than that of aged LB. The maximum adsorption capacities of Pb(II) on fresh biochar at 350 °C and 650 °C were 279.85 and 286.07 mg·g-1 and on aged biochar were 242.57 and 159.82 mg·g-1, respectively. The adsorption capacity of HB for Pb(II) was higher than that of LB, and the adsorption capacity of aged biochar for Pb(II) decreased obviously, which might be attributable to changes in physicochemical properties of biochar after the aging treatment.

Cu2+ and Fe2+ Sensor Based on CdTe QD@ZIF-8 Composites.

TGA capped CdTe QDs have been encapsulated in miroporous ZIF-8, with no obvious deterioration of their photoluminescence property. The resulted CdTe QD@ZIF-8 composites show a higher luminescent stability in various buffer solution. The material has successfully been used as a luminescent indicator for the detection of Cu2+ and Fe2+ ions. The luminescence of CdTe QD@ZIF-8 composite quenches only in the presence of Cu2+ or Fe2+ ions. The linear ranges of detection have been estimated as 1~50 uM for Cu2+ ions and 1~60 uM for Fe2+ ions, respectively. A "competing transmission" mechanism has been proposed to explain the selectivity of the sensor to detecting Cu2+ and Fe2+ ions. Luminescent quenching can only occurred when the bonding power of QD surface surpasses the adsorptivity of the outside ZIF-8 to the metal ions.

Antioxidant status and gut microbiota change in an aging mouse model as influenced by exopolysaccharide produced by Lactobacillus plantarum YW11 isolated from Tibetan kefir.

This study investigated the effect of exopolysaccharide (EPS) produced by Lactobacillus plantarum YW11 on the oxidative status and gut microbiota in an aging mouse model induced with d-galactose. The in vitro assay of the antioxidant activity of the EPS showed concentration-dependent (0.25-3.0 mg/mL) activities. At 3.0 mg/mL, the EPS reached the highest scavenging activities with half maximal inhibitory concentration values against hydroxyl radicals at 75.10% and 1.22 mg/mL, superoxide anion at 62.71% and 1.54 mg/mL, 2, 2-diphenyl-1-picrylhydrazyl at 35.11% and 0.63 mg/mL, and the maximal chelating rate on ferrous ion and the half-maximal chelating concentration of the EPS at 41.09% and 1.07 mg/mL, respectively. High doses of EPS (50 mg/kg per day) effectively relieved the oxidative stress in the aging mice with increased levels of glutathione peroxidase, superoxide dismutase, catalase, and total antioxidant capacity in mice serum by 21.55, 33.14, 61.09, and 38.18%, respectively, and decreased malondialdehyde level from 11.69 to 5.89 mmol/mL compared with those in the untreated aging mice model. The analysis of pyrosequencing sequence data from the gut microbiota revealed that the EPS could recover the microbiota diversity and phylotypes decreased or eliminated by the d-galactose treatment. The EPS could selectively decrease the abundance of Flexispira (37.5 fold), and increase the abundance of Blautia (36.5 fold) and Butyricicoccus (9.5 fold), which correspondingly decreased the content of nitrogen oxides to 9.87% and increased the content of short-chain fatty acids by 2.23 fold, thereby improving the oxidative and health conditions of the host intestinal tract. Further correlation analysis of core-microbiota variation induced by different treatments showed a strong correlation with oxidative phenotypes [catalase, goodness of prediction (Q2) = 0.49; total antioxidant capacity, Q2 = 0.45; nitrogen oxides, Q2 = 0.67; short-chain fatty acids, Q2 = 0.55]. The fermented milk with L. plantarum YW11 containing EPS also showed favorable antioxidant and gut microbiota regulating activities. The present finding provided new insights into the functional mechanism of probiotics bioactivity.

Controllable Synthesis of Polyhedral Fe3O4 Hollow Spheres Using Hexamethylenetetramine as Structure-Directing Agent.

Polyhedral Fe3O4 hollow spheres were synthesized using hexamethylenetetramine as structure-directing agent and the effect of hexamethylenetetramine on the morphology was investigated in detailed. The comparison for samples prepared with and without hexamethylenetetramine indicated that hexamethylenetetramine played a vital role in the formation process of the hollow polyhedral structure. The formation process and growth mechanism of Fe3O4 spheres with hollow polyhedral morphology were preliminarily explored according to a detailed time-dependent morphology and structure evolution. It was deduced that the hollow polyhedral structure can be ascribed to the cooperation of oriented aggregation and Ostwald ripening mechanisms. The as-prepared Fe3O4 hollow spheres with polyhedral structures which possess high magnetization saturation value (73 emu/g) at room temperature, large cavity and huge specific surface area (57.12 m2·g­1) are expected to have wide potential applications, for example in the drug delivery process, magnetic separation and waste treatment in the future.