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Chitosan (CTS)/chitosan oligosaccharide (COS) and whey protein isolate (WPI) have been frequently used as food supplements, but notably, the interaction between the carbohydrate and the protein may affect the digestibility of protein. Thus, the present study focused on effects of the interaction between CTS/COS and WPI on the protein digestibility. A series of chemical and spectroscopic techniques including gel electrophoresis, gel permeation chromatography, Fourier transform-infrared (FT-IR) spectroscopy, intrinsic fluorescence (IF) spectroscopy, and circular dichroism (CD) spectroscopy were applied. According to the findings, both CTS and COS dramatically reduced intestinal digestibility of WPI, resulting in a decrease of DH by 43.33 % and 52.31 %, respectively. The substitution degree of WPI on CTS was 0.87 g WPI/g CTS, and the electrostatic interaction between amine groups of CTS and carboxyl groups of WPI caused changes in WPI's stability, microstructure, and fluorescence intensity. Notably, CTS affected the digestibility of WPI by precipitating protein and enzyme, whereas COS altered WPI's digestibility by decreasing or inactivating enzyme activity. The present study offered a solid scientific foundation for the rational formulations of carbohydrates and proteins in food industry. [Display omitted] • Chitosan (CTS) and its oligosaccharide (COS) influenced protein digestibility. • CTS decreased protein digestibility by partially precipitating protein and protease. • COS influenced protein digestibility by decreasing the activity of protease. • The electrostatic interaction occurred between -NH 3 + of CTS and -COO− of protein. [ABSTRACT FROM AUTHOR]

Chitosan (CTS) and chitosan oligosaccharides (COS) have been widely applied in food industry due to their bioactivities and functions. However, CTS and COS with positive charges could interact with proteins, such as whey protein isolate (WPI), influencing their digestion. Interaction among CTS/COS, FUC, and WPI/enzymes was studied by spectroscopy, chromatography, and chemical methods in order to reveal the role of FUC in relieving the inhibition of protein digestibility by CTS/COS and demonstrate the action mechanisms. As shown by the results, the addition of FUC increased degree of hydrolysis (DH) and free protein in the mixture of CTS and WPI to 3.1-fold and 1.8-fold, respectively, while raise DH value and free protein in the mixture of COS and WPI to 6.7-fold and 1.2-fold, respectively. The interaction between amino, carboxyl, sulfate, and hydroxyl groups from carbohydrates and protein could be observed, and notably, FUC could interact with CTS/COS preferentially to prevent CTS/COS from combining with WPI. In addition, the addition of FUC could also relieve the combination of CTS to trypsin, increasing the fluorescence intensity and concentration of trypsin by 83.3 % and 4.8 %, respectively. Thus, the present study demonstrated that FUC could alleviate the inhibitory effect of CTS/COS on protein digestion. [Display omitted] • FUC alleviated the negative impact of CTS and COS on protein digestibility. • CTS/COS interacted with FUC preferentially and thus WPI was released. • Electrostatic interaction occurred between -NH 3 + of CTS/COS and -SO 4 2− of FUC. • FUC could hinder the combination of CTS and trypsin. [ABSTRACT FROM AUTHOR]

Background: The impacts of increasing nitrogen (N) deposition and overgrazing on terrestrial ecosystems have been continuously hot issues. Grazing exclusion, aimed at restoration of grassland ecosystem function and service, has been extensively applied, and considered a rapid and effective vegetation restoration method. However, the synthetic effects of exclosure and N deposition on plant and community characteristics have rarely been studied. Here, a 4-year field experiment of N addition and exclusion treatment had been conducted in the desert steppe dominated by Alhagi sparsifolia and Lycium ruthenicum in northwest of China, and the responses of soil characteristics, plant nutrition and plant community to the treatments had been analyzed. Results: The grazing exclusion significantly increased total N concentration in the surface soil (0-20 cm), and increased plant height, coverage (P < 0.05) and aboveground biomass. Specifically, A. sparsifolia recovered faster both in individual and community levels than L. ruthenicum did after exclusion. There was no difference in response to N addition gradients between the two plants. Conclusions: Our findings suggest that it is exclusion rather than N addition that has greater impacts on soil properties and plant community in desert steppe. Present N deposition level has no effect on plant community of desert steppe based on short-term experimental treatments. [ABSTRACT FROM AUTHOR]

Excessive protein consumption (EPC) could increase the gastrointestinal burden and impair gut motility. The present study was designed to explore the improvement of chitosan (CTS) and chitosan oligosaccharide (COS) on colonic motility and serum metabolites in rats after EPC. The results of in vivo experiments fully proved that CTS and COS could improve gut motility and reverse the serum metabolites in rats as indicated by LC-MS/MS analysis, and the COS group even showed a better effect than the CTS group. Furthermore, short-chain fatty acids (SCFAs), which could promote gut motility, were also increased to alleviate EPC-induced constipation after supplementation with CTS or COS. In addition, CTS and COS could decrease the concentration of ammonia in serum and down-regulate the levels of H 2 S and indole. In summary, the present study revealed that CTS and COS could produce SCFAs, improve the colonic motility in rats, reverse the levels of valine, adenosine, cysteine, 1-methyladenosine, indole, and uracil, and enhance aminoacyl-tRNA biosynthesis and valine, leucine and isoleucine degradation. The present study provides novel insights into the potential roles of CTS and COS in alleviating the adverse effects of EPC. [Display omitted] • COS was superior to CTS in relieving the negative effects of EPC. • The levels of SCFAs were increased by both CTS and COS to improve colonic motility. • CTS and COS reversed the changes in serum metabolite profiles caused by EPC. • Both CTS and COS decreased the levels of serum ammonia, H 2 S, and indole. [ABSTRACT FROM AUTHOR]

In the present study, a fucoidan fraction (ANP-3) was isolated from Ascophyllum nodosum , and the combined application of desulfation, methylation, HPGPC, HPLC-MSn, FT-IR, GC–MS, NMR, and Congo red test elucidated ANP-3 (124.5 kDa) as a triple-helical sulfated polysaccharide constituted by →2)-α-Fuc p 3 S -(1→, →3)-α-Fuc p 2 S 4 S -(1→, →3,6)-β-Gal p 4 S -(1→, →3,6)-β-Man p 4 S -(1→, →3,6)-β-Gal p 4 S -(1→，→6)-β-Man p -(1→, →3)-β-Gal p -(1→, α-Fuc p -(1→, and α-GlcA p -(1→ residues. To better understand the relationship between the fucoidan structure of A. nodosum and protective effects against oxidative stress, two fractions ANP-6 and ANP-7 were used as contrast. ANP-6 (63.2 kDa) exhibited no protective effect against H 2 O 2 -induced oxidative stress. However, ANP-3 and ANP-7 with the same molecular weight of 124.5 kDa could protect against oxidative stress by down-regulating reactive oxygen species (ROS) and malondialdehyde (MDA) levels and up-regulating total antioxidant capability (T-AOC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities. Then metabolites analysis indicated that arginine biosynthesis and phenylalanine, tyrosine, and tryptophan biosynthesis metabolic pathways and metabolic biomarkers such as betaine were involved in the effects of ANP-3 and ANP-7. The better protective effect of ANP-7 compared to that of ANP-3 could be attributed to its relatively higher molecular weight, sulfate substitution and →6)-β-Gal p -(1→ content, and lower uronic acid content. [Display omitted] • The ANP-3 backbone mainly consisted of →3)-α-Fuc p 2 S 4 S -(1→ and →2)-α-Fuc p 3 S -(1→. • ANP-3 and ANP-7 with higher-MWs could reduce oxidative stress while ANP-6 could not. • ANP-3 and ANP-7 inhibited oxidative stress by modulating arginine biosynthesis. • ANP-7 with high sulfate content and molecular weight exhibited a stronger effect. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lycium barbarum arabinogalactan (LBP-3) can be utilized by Bacteroidetes species. • Of 10 tested species, P. vulgatus and B. caccae are more powerful to utilize LBP-3. • P. vulgatus and B. caccae preferred to Ara and Gal residues in LBP-3, respectively. • Oligosaccharides generated by P. vulgatus and B. caccae were identified by LC-MS n. • Their fermentation products with mono/oligo-saccharides influence others' growths. The present study investigated the utilization of an arabinogalactan from Lycium barbarum (LBP-3) by intestinal Bacteroidetes species. The mixed-culture assay showed 58.4 % LBP-3 was utilized, and Bacteroides caccae and Phocaeicola vulgatus utilized more LBP-3 in single-culture compared to others. During in vitro fermentation of LBP-3, P. vulgatus favored arabinose while B. caccae preferred galactose. Moreover, 9 and 25 oligosaccharides were identified by HPLC-MS n in conditioned media (CM) derived from B. caccae and P. vulgatus , respectively. All of 3 tested Parabacteroides species (P. distasonis , P. goldsteinii , and P. johnsonii) markedly proliferated in CM of B. caccae and P. vulgatus , and proliferations of B. uniformis , B. finegoldii , B. ovatus and B. thetaiotaomicron also increased significantly in CM of B. caccae. The study suggests that the ability of Bacteroidetes species to degrade LBP-3 and sheds light on cooperative interactions of Bacteroides, Phocaeicola , and Parabacteroides species in the presence of LBP-3. [ABSTRACT FROM AUTHOR]

Salinization is an important and increasingly prevalent issue which has broad and profound effects on plant survival and distribution pattern. To understand the patterns and potential drivers of leaf traits in saline environments, we determined the soil properties, leaf morphological traits (specific leaf area, SLA, and leaf dry matter content, LDMC), leaf chemical traits (leaf carbon, C, nitrogen, N, and phosphorus, P, stoichiometry) based on 142 observations collected from 23 sites in an arid saline environment, which is a vulnerable ecosystem in northwest China. We also explored the relationships among leaf traits, the responses of leaf traits, and plant functional groups (herb, woody, and succulent woody) to various saline environments. The arid desert halophytes were characterized by lower leaf C and SLA levels, higher N, but stable P and N:P. The leaf morphological traits were correlated significantly with the C, N, and P contents across all observations, but they differed within each functional group. Succulent woody plants had the lowest leaf C and highest leaf N levels among the three functional groups. The growth of halophytes might be more limited by N rather than P in the study area. GLM analysis demonstrated that the soil available nutrients and plant functional groups, but not salinity, were potential drivers of leaf C:N:P stoichiometry in halophytes, whereas species differences accounted for the largest contributions to leaf morphological variations. Our study provides baseline information to facilitate the management and restoration of arid saline desert ecosystem. [ABSTRACT FROM AUTHOR]

• A polysaccharide-Fe(III) complex, AGSP-Fe(III), was synthesized and characterized. • Fe release of AGSP-Fe(III) in simulated gastrointestinal digestion was exhibited. • Its iron supplementary efficiency was shown using Caco-2 cell model. • The solubility and stability of the complex were superior to FeCl 3. Using a sulfated polysaccharide from the gonad of pacific abalone (AGSP), a novel polysaccharide-Fe(III) complex, AGSP-Fe(III), was synthesized, and it was characterized by a series of methods including ultraviolet-visible (UV–vis) spectroscopy, Fourier transform-infrared (FT-IR) spectroscopy, circular dichroism (CD) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results showed that AGSP-Fe(III) was formed by the Fe-O bond between sulfate, carboxyl, and hydroxyl groups in AGSP and Fe, its particle size reached a maximum of 200 nm after aggregating, and its surface morphology presented relatively regular columnar or spherical. Moreover, the iron release of AGSP-Fe(III) during simulated gastrointestinal digestion was exhibited, and its good iron supplementary efficiency was also shown using Caco-2 cells. In addition, compared to FeCl 3 , AGSP-Fe(III) showed better solubility and stability in the presence of polyphenol/trypsin. The present study demonstrated the potential of AGSP-Fe(III) as a novel iron supplement. [ABSTRACT FROM AUTHOR]

Background: Soil salinity is a major abiotic constraint to plant growth and development in the arid and semi-arid regions of the world. However, the influence of soil salinity on the process of nutrient resorption is not well known. We measured the pools of both mature and senesced leaf nitrogen (N), phosphorus (P), potassium (K), and sodium (Na) of desert plants from two types of habitats with contrasting degrees of soil salinity in a hyper-arid environment of northwest China. Results: N, P, K revealed strict resorption, whereas Na accumulated in senesced leaves. The resorption efficiencies of N, P, and K were positively correlated with each other but not with Na accumulation. The degree of leaf succulence drives both intra-and interspecific variation in leaf Na concentration rather than soil salinity. Both community- and species-level leaf nutrient resorption efficiencies (N, P, K) did not differ between the different habitats, suggesting that soil salinity played a weak role in influencing foliar nutrients resorption. Conclusions: Our results suggest that plants in hyper-arid saline environments exhibit strict salt ion regulation strategies to cope with drought and ion toxicity and meanwhile ensure the process of nutrient resorption is not affected by salinity. [ABSTRACT FROM AUTHOR]

• This study has provided disaccharide data of Cyclina sinensis for the first time. • There are mainly 6 disaccharides in Cyclina sinensis. • A potential strategy to identify mixed polysaccharides without purification. It is still a challenge to identify mixed polysaccharides isolated from biological tissues. The present study aimed to develop a protocol that allowed for quick characterization of mixed polysaccharides by selecting Cyclina sinensis polysaccharides as test beds. Disaccharides were gradually released by graded acid hydrolysis, separated with 3 kDa molecular weight cut-off membrane, and analyzed by HPLC-ESI-MSn. Furthermore, the monosaccharide composition of the filtrate during the gradient acid hydrolysis process and the final retentate were also determined to provide composition information of these disaccharides. Thus, 6 disaccharides were detected and identified, indicating the existence of polysaccharides constructed of corresponding repeated disaccharide fragments in C. sinensis. The present study demonstrated a potential strategy to characterize mixed polysaccharides without separation and purification. [ABSTRACT FROM AUTHOR]

In the present study, two polysaccharides, SVP2–1 and SVP2–2, were isolated from Patinopecten yessoensis viscera and purified by using DEAE-52 cellulose and Sepharose CL-6B. Both SVP2–1 and SVP2–2 could extend activated partial thromboplastin time (APTT) and thrombin time (TT) and inhibit the transformation of fibrinogen into fibrin (FIB) concentration-dependently, indicating they inhibited clotting and thrombin through intrinsic and common pathways. Of note, SVP2–2 had stronger anticoagulant activity than SVP2–1, and its backbone was determined as →6)-α-Man p (1 → 2)-α-Gal p (1 → with Xyl or Glc substituted at C4 of Gal. Based on monosaccharide composition analysis, methylation analysis, and NMR analysis. Further comparison of their monosaccharide analysis and NMR spectra indicates SVP2–1 and SVP2–2 possess the same core structure features, so the higher sulfate content and lower molecular weight may be the possible reasons for the stronger anticoagulant capability of SVP2–2. The present study suggests acidic polysaccharides from scallop viscera as promising anticoagulant candidates. • Two polysaccharides from scallop viscera were purified and characterized. • They inhibited clotting and thrombin through intrinsic and common pathways. • SVP2–2 with higher sulfate content exhibited stronger anticoagulant effect. • The backbone of SVP2–2 was →6)-α-Man(1 → 2)-α-Gal(1 → with Xyl and Glc at C-4 of Gal. [ABSTRACT FROM AUTHOR]

Drought seriously endangers the development of agro‐pastoral ecotone in arid and semi‐arid regions. However, drought evolution characteristics of semi‐arid sandy grassland and its drivers are not well understood in the complex climate change context. Thus, in this paper, the revised standardized precipitation evaporation indices on one‐month (SPEI‐1) and growing‐season (SPEI‐6) scale, flash drought and dry spells (DS) were calculated as drought indicators, and the temporal variabilities and meteorological drivers of drought in Horqin Sandy Land during the growing period (April–September) from 2007 to 2021 were studied. The results showed that SPEI‐1 and SPEI‐6 exhibited negative trends and periodic change. This drought aggravation was manifested in increased grades and numbers of drought months. Flash droughts can occur every month during the growing season. And its occurrence was not only positively correlated with all drought events in frequency but also synchronized in time. The increased number of DS showed an asymmetrical shift towards 7‐day‐and‐longer DS. SPEI sensitivity to precipitation (P) was noticeably higher than to atmospheric evapotranspiration demand (AED) at both monthly and growing season scales. SPEI sensitivity to AED was modulated by P amounts, which was higher during low P period. Apart from the amounts of P and AED, their temporal variability also strongly determined how they affect the drought severity. P was also the main driver for flash drought and long DS, but AED with larger amount and higher variability is the reason for their aggravation. Our results demonstrate the complexity of drought intensification in semi‐arid sandy grasslands and highlight the important role of AED anomalies in it. [ABSTRACT FROM AUTHOR]

Although numerous polysaccharides have demonstrated potential immunostimulatory activities in in vitro models, only a few of them successfully stimulate the immune system in vivo. In order to explore the possible reasons for the activity loss of polysaccharides in in vivo models, the immunostimulatory activities in vitro and in vivo and the digestion behavior of a polysaccharide from Cyclina sinensis (CSP) were investigated in the present study. CSP showed obvious immunostimulatory activity in a RAW 264.7 cell model. In in vitro experiment, CSP did not exhibit cytotoxicity at concentrations of ≤10 µg/ml, and significantly increased NO production at concentrations of 0.4–10 µg/ml, suggesting CSP processes immunostimulatory activity in vitro. Further investigation using simulated digestion model indicated that CSP could bind with the protein in the digestive fluids to form precipitate in both the stomach and small intestine, and it could be seriously degraded by amylase during the digestion in the small intestine. Furthermore, the in vivo immunostimulatory activity evaluation demonstrated CSP had no effect on immunosuppressed mice as indicated by the body weight, thymus and spleen indexes, and TNF‐α, IL‐1β, IL‐6, and IL‐10 mRNA expression. Thus, the present study indicates that the degradation and precipitation of CSP in the digestive tract are the possible reasons for the activity loss of CSP after digestion. Practical Application: Cyclina sinensis is the common aquatic shellfish in China and plays an important role in the marine aquaculture industry. Cyclina sinensis polysaccharide (CSP) is the main active component of C. sinensis. The structure characterization and immunostimulatory activity of a purified fraction of CSP (CSP‐1) and the effect of digestion on CSP and its immunostimulatory activity were studied. The result of this study promotes the understanding of the nutritional function effects and provides a scientific reference for the rational development and high‐value utilization of C. sinensis. [ABSTRACT FROM AUTHOR]

• Bacteria and eukaryota diversity increased with increasing longitude and elevation. • Archaeal diversity decreased slightly with increasing elevation. • Some phyla diversity patterns are individually inconsistent with the overall trend. • Geographic distance contributed more than environmental factors to soil microbes. • More intra-domain than inter-domain links within the soil microbial network. Recent studies show that different microorganisms, especially bacteria and fungi, exhibit contrasting latitudinal, longitudinal, and altitudinal diversity patterns at a global scale, but little is known about biogeographic patterns in desert ecosystems. In this study, we chose a narrow geographic channel, namely the deserts of northern China's Hexi Corridor as the study area. Based on field survey and next-generation sequencing (Illumina MiSeq PE300 Platform), to map soil microbial geographic diversity patterns in this area and further determine the main driving factors responsible for shaping the soil microbial community. The results show that bacteria and eukaryotic diversity increased linearly with increasing longitude and altitude, but decreased with increasing latitude in the Hexi Corridor deserts, whereas archaeal diversity showed little change along these geographic gradients. Some individual phyla within the bacterial, archaeal, and eukaryota communities were not always consistent with collective trends, e.g., for the α-diversity of the ten most dominant bacterial phyla, only six phyla showed a statistically significant increase with altitude. The soil microbial community composition was jointly shaped by geographic distance and environmental variables (regional climatic factors and local edaphic variables). The effect of geographic distance on the soil microbial community composition was slightly stronger than that of the environmental variables. Intra-domain links were stronger than inter-domain links in the soil microbial network of the Hexi Corridor deserts, and these links were mostly positive. Although bacteria formed more connections than both archaea and eukaryotes, removing the archaea resulted in a lower natural connectivity, suggesting that the archaea were the core group for building this desert region's soil microbial co-occurrence network. Taken together, these findings deepen our understanding of regional-scale soil microbial diversity patterns in this desert ecosystem. [ABSTRACT FROM AUTHOR]

The surface free energy is an important parameter that can be used to estimate the adhesion work of asphalt binder and aggregates system. Based on the theory of surface physical chemistry, the surface free energy of the base asphalt and asphalt modified by natural asphalt is determined by measuring contact angles with the sessile drop method. The adhesion grade of asphalt and aggregate is obtained by the boiled water method. The method of calculating adhesion work is studied first. Then, the adhesion work of asphalt aggregate systems and asphalt aggregate water systems are determined, respectively. Test results show that by increasing the additive of natural asphalt, the adhesion work of natural asphalt modifier asphalt and aggregate elevates distinctly, and the adhesion work of the modified asphalt, aggregate and water system decreases. There is a good relation between the adhesion grade and the adhesion work of dry and the adhesion work in the presence of water. The additive of natural asphalt improves the moisture damage resistance. [ABSTRACT FROM AUTHOR]

Caulerpa lentillifera (Bryopsidophyceae, Chlorophyta) is an edible seaweed attracting great attention for its expansion of farming scale and increasing consumption in these years. In the present study, a sulfated polysaccharide (CLSP-2) was isolated and separated from C. lentillifera , and its chemical structure was elucidated by a series of chemical and spectroscopic methods. Among these methods, mild acid hydrolysis and photocatalytic degradation were applied to release mono- and oligo-saccharide fragments which were further identified by HPLC-MSn analysis, affording the information of the sugar sequences and the sulfate substitution in CLSP-2. Results indicated that the backbone of CLSP-2 was constructed of →6)-β-Man p -(1→ with sulfated branches at C2, which were comprised of prevalent →3)-β-Gal p 4S-(1→, →3)-β-Gal p 2,4S-(1→, and minor Xyl. In addition, the virus neutralization assay revealed that CLSP-2 could effectively protect HeLa cells against SARS-CoV-2 infection with an IC 50 of 48.48 μg/mL. Hence, the present study suggests CLSP-2 as a promising agent against SARS-CoV-2. [ABSTRACT FROM AUTHOR]

The electronic properties at the donor (D):acceptor (A) interface are a crucial factor in determining the efficiency of organic photovoltaic devices. Here, based on first-principles calculations, the electronic properties of ten configuration complexes composed of D polymer PDPPTPT and A polymer PNDI2OD-TVT were simulated. Results show that the bandgap values of the homo-/heterojunctions decrease with the increase of the number of molecular layers, and that of AAA is close to zero. This indicates that the homogeneous stacking is favorable for charge transport; furthermore, the bandgap of the complexes is affected by the molecular arrangement. Through the differential charge density and Bader charge analysis method, it was found that charge transfer will occur intermolecularly, which promotes the formation of a dipole moment at the D:A interface, and the dipole electric field then helps the dissociation of excitons in the active layer. The amount of charge transfer at the D:A interface in the DDA, DAA and DDAA configurations is about twice that in the DA configuration alone, demonstrating that homogeneous accumulation in complexes can enhance the interface dipole interaction. The comprehensive analysis suggests that homogeneous accumulation is conducive to charge transport, that heterogeneous stacking helps to promote exciton dissociation, and that there should be an optimal ratio. Furthermore, the dipole electric fields formed at the D:A interface exhibit the characteristics of local and non-uniform distribution. [ABSTRACT FROM AUTHOR]

Cyclina sinensis is an edible clam widely distributed along the coastal waters of Asia. In the present study, a polysaccharide (CSP-1) isolated from C. sinensis was purified by a DEAE-Sepharose Fast Flow column, and it had an average molecular weight of 3.8 × 105 Da and a prevalent component monosaccharide of Glc. The results of methylation analysis and 1D/2D NMR indicated that CSP-1 was a glycogen constructed with α-1,4-Glc and branched at C-6 every 9 Glc residues. In addition, Cong red test suggests CSP-1 was not a helical conformation, and irregular and spherical lumps were observed by AFM. Moreover, CSP-1 was found to possess potent immunostimulatory activity on the basis of its significant abilities to enhance NO production and cytokines (TNF-α, IL-1β and IL-6) secretion in RAW 264.7 macrophages. [ABSTRACT FROM AUTHOR]

Mowing and burning, two common human disturbance methods, have different impacts on the soil fungal and bacterial communities of sandy land ecosystems in semiarid areas. Thus, the effects of long-term mowing and burning on plant and soil microbial communities in the semiarid Horqin Sandy Land are unclear. In this study, the effects of soil microbial community structure from mowing and burning on plant and soil microbial communities over six years were assessed by high-throughput sequencing. First, we found that mowing and burning significantly reduced vegetation coverage (V) (p < 0.05), and burning significantly increased plant Shannon–Wiener diversity (H), Pielou evenness (E), and Simpson dominance (λ) indices (p < 0.05). Second, the two human disturbances markedly affected fungal diversity and abundance more than bacterial diversity and abundance. In fungi, burning significantly reduced beta diversity (p < 0.05) and the relative abundance of Basidiomycota (p < 0.05) but markedly increased the relative abundance of Ascomycota and Mortierellomycota. Third, redundancy analysis (RDA) showed that vegetation coverage was a significant factor in bacterial species distribution (p < 0.05). For fungi, the significant factors were species richness (S) and vegetation coverage (p < 0.01). Taken together, these data suggest that long-term mowing and burning have more of an effect on soil fungal communities than bacteria in a semiarid sandy land, improving our understanding of how terrestrial ecosystems respond to human disturbances and providing guidance for the management and restoration of sandy desertification. • Mowing significantly reduced vegetation coverage. • Burning could change the plant community diversity. • Mowing and burning markedly affected fungal diversity and abundance more than bacteria. • Vegetation coverage was the significant factor in bacteria species distribution. • Fungal community was more easily influenced by plant community diversity. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The surface energy of coal was assessed based on mechanical testing. • The surface energy of specimens decreased with increasing temperature. • The variability of the surface energy among the specimens was caused by composition. • The surface energy of specimens decreased with increasing roughness. Abstract In order to assess the applicability of mechanical method for testing the surface energy of coal, the surface energy of ten coal specimens of two macroscopic lithotypes (semidull and semibright) with metamorphic degree in anthracite stage and a carbonaceous mudstone specimen from a certain mine were tested and analyzed at different temperatures. The results showed that the measurements of surface energy are affected by the test methods, test temperature, coal macerals and minerals, and coal surface roughness. For coal and rock solid materials with strong heterogeneity, the mechanical method is simpler than the optical method and the error is smaller. The surface energy of coal specimens varies from 22.08 to 28.08 mJ·m−2 at room temperature of 293 K by mechanical method. With the increase of temperature, the surface energy of the specimens decreases linearly, and the coefficient of variation of the measured surface energy of various specimens exponentially increased. The surface energy of carbonaceous mudstone specimen is the largest, followed by semidull coal specimens and semibright coal specimens. In contrast, the order of decrease rate of surface energy with temperature increases is semibright coal, semidull coal and carbonaceous mudstone. The surface energy of the specimens exhibited a negative exponentially decreasing trend as the surface roughness increased. The study results provide a basis for further improving the test methods of the surface energy of heterogeneous solid materials, and the application of engineering methods to improve the extraction efficiency of coalbed methane by changing temperature. [ABSTRACT FROM AUTHOR]

Chondroitin sulfate (CS) is widely known for its various biological activities which are closely related to the sulfate substitution and the molecular weight. Effective degradation methods without striping sulfate groups are in a need. In the present study, a photocatalytic degradation method using H 2 O 2 and TiO 2 has been developed and it could decrease the average molecular weight of CS into 5 kDa within 6 h. The chemical composition of CS before and after degradation were compared by FT-IR, NMR, etc. , and no removement of sulfate group was observed. Then the identification of the oligosaccharides in the degradation product by mass spectroscopy revealed that glucuronic acid or its derivative, arabinuronic acid, was at most of the reducing ends, and the depolymerization mechanism was proposed. Furthermore, the absorption of CS in rats was enhanced by the degradation while the excertion profile of the degradation product was similar to that of CS. [Display omitted] • A photocatalytic method is developed for chondroitin sulfate (CS) degradation. • It could depolymerize CS to 5 kDa within 6 h without stripping sulfate groups. • Most of oligosaccharide have glucuronic acid or its derivative at reducing ends. • Gut microbiota metabolize CS and its degradation product (3 kDa) at a similar level. [ABSTRACT FROM AUTHOR]

• 4300 km long transects were established in the ecologically fragile areas of China. • Soil C:N:P stoichiometry in ecologically fragile areas was well-constrained. • C:N:P stoichiometry differed among the areas in response to environmental changes. • Climate and vegetation factors were the key drivers of soil C:N:P stoichiometry. Researchers are paying increasing attention to soil stoichiometry (carbon:nitrogen:phosphorus (C:N:P) ratios) in efforts to explore biogeochemical cycles, but little is known about the spatial pattern, implications, and driving factors of this stoichiometry in large, ecologically fragile areas. To explore these factors, we established three transects that covered a total length of about 4300 km in ecologically fragile areas of China, and sampled at intervals of about 25 km. These transects covered the karst area and the agro-pastoral ecotone of southwestern China, the Qinghai-Tibet Plateau, the Loess Plateau, and the forest-grassland ecotone. We collected 312 soil samples to a depth of 30 cm from 156 plots. The soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) in the ecologically fragile areas showed strong coupling relationships. Soil C:N:P was 51:4:1 to a depth of 30 cm, which is lower than the average global C:N:P (111:8:1). SOC and TN concentrations at 0 to 20 cm were significantly higher than that at 20 to 30 cm, but TP did not differ significantly among depths. SOC, TN, and TP concentrations were highest in the agro-pastoral ecotone, and were lowest in the Loess Plateau. C:N, C:P, and N:P were highest in the karst area. C:N were lowest in the Qinghai-Tibet Plateau, and C:P and N:P were lowest in the Loess Plateau. The spatial pattern of C, N, and P stoichiometry along environmental gradients was variable. The contributions to explaining the soil stoichiometry were highest for climate (21.7%), vegetation (8.9%), soil properties (6.4%), and topography (0.6%) to a depth of 20 cm, versus vegetation (35.9%), climate (5.3%), soil properties (3.3%), and topography (2.1%) at 20 to 30 cm. The results provide new insights into the biogeochemical cycles of C, N, and P and guidance for their impacts on ecological restoration in ecologically fragile areas. [ABSTRACT FROM AUTHOR]

Plant litter derived from the living biomass is the primary source of soil carbon (C). However, the contribution and the mechanism of plant litter production to soil C remains uncertain in aeolian regions. In this study, the relationship between plant biomass, litter mass, and soil C content was analyzed after a spatial field investigation in Horqin sandy land, northeast China. Long-term monitoring of wind speed and plant litter production was also conducted in three habitats (mobile dune, semi-fixed dune, and fenced grassland). The soil C content was significantly affected by belowground biomass and belowground litter mass but not aboveground biomass and aboveground litter. The litter production in the desertified habitat (mobile dune and semi-fixed dune) significantly differed with that of the undesertified habitat (fixed dune and fenced grassland). In mobile dune, 38% of the aboveground primary production was lost, while there was a distinct enrichment of plant litter in semi-fixed dune and fenced grassland. Wind events (wind speeds of 7 and 8 m s−1) at the end of the growing season significantly affected litter production rate, and wind was a major driver for litter transportation between habitats. In summary, plant litter production can be affected by wind events, and this influence differs among habitats in degraded grassland, leading to spatial heterogeneity of soil C accumulation. These results can strengthen the understanding of the relationship between soil properties and plant litter production in aeolian regions and furthermore, can provide information for ecological restoration of different types of desertified land, especially for the soil C accumulation. Plant litter is the major source for soil organic matter accumulation. In degraded sandy grasslands in semi-arid regions, wind is a visible factor which transported the aboveground litter from regions with lower vegetation coverage (e.g. mobile dune or semi-fixed dune) to regions with higher vegetation coverage (e.g. fixed dune or fenced grassland), which means that, wind is the driving force for the source-sink relationships of plant litters. There remains no clear description of the influence of wind events on litter production and litter distribution. The contribution of plant litter production to soil C remains uncertain in aeolian regions. The schematic diagram strengthened the understanding of the relationship between soil properties and plant litter production, and providing important information for ecological restoration in semi-arid sandy grasslands. [Display omitted] [ABSTRACT FROM AUTHOR]

Grassland has sustained serious desertification due to inappropriate human activity in arid and semi-arid areas. This desertification has disrupted ecosystem structure and function. However, desertification on the grassland's C:N:P stoichiometry (Carbon, Nitrogen, and Phosphorus) are poorly understood, which undermines management and restoration of desertified grassland. To improve our knowledge, we studied a desertification gradient in Northeastern China's Horqin Sandy Land to determine the effects of desertification on ecosystem function, the plant community, and soil C:N:P stoichiometry. The soil and plant community C, N and P pools decreased during desertification. Under severe desertification, the soil C:N decreased by 17.4%, versus 39.2% for C:P and 50.1% for N:P. This implies non-proportional losses of soil organic C and nutrients, with the greatest loss for organic C, followed by total N and total P. Plant aboveground C:N and C:Pand belowground C:N increased, suggesting increased nutrient utilization efficiency. Canonical correspondence analysis ordination showed that soil N and P significantly affected the plant species composition, which was associated with plant C:N:P. The desertified grassland's fertility (especially N) directly determined the plant community C, N, and P concentrations and C:N:P ratios. The increased dominance of two psammophytes, Agriophyllum squarrosum and Artemisia halodendron decreased plant community C, N, and P concentrations, but increased C:N and C:P. Thus, plant community C:N:P stoichiometry was mediated by soil nutrients and plant functional groups driven by soil nutrient changes during desertification. The soil nutrient imbalance potentially changed plant community composition, this then altered the soil chemical composition because plant species differ in their element contents and litter inputs. Hence, species with high N content could improve grassland restoration by mitigating N limitations. The native psammophytes A. squarrosum and A. halodendron , with high stress resistance and resource utilization efficiency, could be applied in desertified grassland restoration. • How desertification impacts the element balance of grassland ecosystem is unclear. • The rate of losses of soil nutrients was in the order organic C > total N > total P. • Imbalance of soil nutrients lead to changes in plant community composition and thus community C:N:P stoichiometry. • Plants with high nutrient content can relieve N limitation of soil in desertified grassland. [ABSTRACT FROM AUTHOR]

Background: Due to the lack of enough interaction data among compositions, targets and diseases, it is difficult to construct a complete network of Traditional Chinese Medicine (TCM) that comprehensively reflects active compositions and their synergistic network in terms of specific diseases. Therefore, mapping of the full spectrum of interaction between compounds and their targets is of central importance when we use network pharmacology approach to explore the therapeutic potential of the TCM. Methods: To address this challenge, we developed a large-scale simultaneous interaction prediction approach (SiPA) integrated one interaction network based simple inference model (SIM), focusing on 'logical relevance' between compounds, proteins or diseases, and another compound-target correlation space based interaction prediction model (CTCS-IPM) that was built on the basis of the canonical correlation analysis (CCA) to estimate the position of compounds (or targets) in compound-protein correlated space. Then SiPA was applied to discover reliable multiple interactions for interaction network expansion of a TCM, compound Salvia miltiorrhiza. By means of network analysis, potential active compounds and their related network synergy underlying cardiovascular diseases were evaluated between expanded and original interaction networks. Part of new interactions were validated with existing experimental evidence and molecular docking. Results: As evaluated with known test dataset, the established combination approach was proved to make highly accurate prediction, showing a well prediction performance for the SIM and a high recall rate of 85.2% for the CTCS-IPM. Then 710 pairs of new compound-target interactions, 24 pairs of new compound-cardiovascular disease interactions and 294 pairs of new cardiovascular disease-protein interactions were predicted for compound Salvia miltiorrhiza. Results of network analysis suggested the network expansion could dramatically improve the completeness and effectiveness of the network. Validation results of literature and molecular docking manifested that inferred interactions had good reliability. Conclusions: We provided a practical and efficient way for large-scale inference of multiple interactions of TCM ingredients, which was not limited by the lack of negative samples, sample size and target 3D structures. SiPA could help researchers more accurately prioritize the effective compounds and more completely explore network synergy of TCM for treating specific diseases, indicating a potential way for effectively identifying candidate compound (or target) in drug discovery. [ABSTRACT FROM AUTHOR]