High-performance reversible aqueous zinc-ion battery based on iron-doped alpha-manganese dioxide coated by polypyrrole.

The development of zinc-ion storage cathode materials for aqueous zinc-ion batteries (AZIBs) is a necessary step for the construction of large-scale electrochemical energy conversion and storage devices. Iron-doped alpha-manganese dioxide (α-MnO2) nanocomposites were achieved in this study via pre-intercalation of Fe3+ during the formation of α-MnO2 crystals. A polypyrrole (PPy) granular layer was fabricated on the surface of α-MnO2 using acid-catalyzed polymerization of pyrroles. The pre-intercalation of Fe3+ effectively enlarges the lattice spacing of α-MnO2 and consequently decreases the hindrance for Zn2+ insertion/extraction in the iron-doped α-MnO2 coated by PPy (Fe/α-MnO2@PPy) composite. Meanwhile, the PPy buffer layer can ameliorate electron and ion conductivity and prevent dissolution of α-MnO2during the charge/discharge process. This unique structure makes the Fe/α-MnO2@PPy composite an efficient zinc-ion storage cathode for AZIBs. The targeted Fe/α-MnO2@PPy cathode achieves superior performance with reversible specific capacity (270 mA h g-1 at 100 mA g-1) and exhibits highdiffusioncoefficientof 10-10-10-14 cm-2 s-1. Therefore, a feasible approach is implemented on advanced electrode materials using in AZIBs for practical applications.

Structural dependence of antidiabetic effect of steviol glycosides and their metabolites on streptozotocin-induced diabetic mice.

BACKGROUND: Stevia has been proposed as a potential antidiabetic sweetener, mainly based on inconsistent results from stevioside or the plant extract, yet lacking relative experimental evidence from individual steviol glycosides (SGs) and their metabolites. RESULTS: The results systematically revealed that the typical SGs and their final metabolite (steviol) presented an antidiabetic effect on streptozotocin (STZ) diabetic mice in all assayed antidiabetic aspects. In general, the performance strength of the samples followed the sequence steviol > steviol glucosyl ester > steviolbioside > rubusoside > stevioside > rebaudioside A, which is opposite to their sweetness strength order, and generally in accordance with the glucosyl group numbers in their molecules. This may imply that the antidiabetic effect of the SGs might be achieved through steviol, which presented antidiabetic performance similar to that of metformin with a dose of 1/20 that of metformin. Moreover, the 18 F-fluorodeoxyglucose traced micro-PET experiment revealed that stevioside and steviol could increase the uptake of glucose in the myocardium and brain of the diabetic mice within 60 min, and decrease the accumulation of glucose in the liver and kidney. CONCLUSIONS: The SGs and steviol presented an antidiabetic effect on STZ diabetic mice in all assayed aspects, with an induction time to start the effect of the SGs. Stevioside and steviol could increase uptake of glucose in the myocardium and brain of the diabetic mice, and decrease accumulation of glucose in the liver and kidney. The performance strength of the SGs is generally in accordance with glucosyl group numbers in their molecules.

What dominates the interfacial properties of extended surfactants: Amphipathicity or surfactant shape?

HYPOTHESIS: The properties of conventional surfactants (c-surfactants) are generally accepted to be amphipathicity-dominated, but extended surfactants (e-surfactants) are additionally polypropylene oxide (PPO)-dependent; this additional property makes us wonder how an intramolecular PPO spacer would be "extended" at various interfaces and what is responsible for the excellent all-round properties of e-surfactants. EXPERIMENTS: A series of novel sodium medium alkyl chain PPO-b-PEO sulfates (2-ethylhexyl polypropylene oxide-block-polyethylene oxide sulfates, C8PpEeS) were designed, synthesized and structurally identified. Tensiometry was applied to estimate the surfactant shape at the air/water surface. Surface tension, interfacial tension, emulsifying power, electrolyte tolerance, adsorption onto oil sands and thermal hydrolysis stability were measured to evaluate the effect of the PPO coil on the interfacial and micellar properties of the e-surfactants. FINDINGS: On the basis of obtaining greater values for e-surfactants than c-surfactants for both surface area (am) per surfactant molecule and the corresponding shape factor (S), we were surprised to find that e-surfactants form a rugby ball shape not only at the air/water surface but also at the oil/water interface; this result is potentially explained by the PPO spacer coiling and collapsing to produce dense packing at the monolayer adsorption, which is rationally borrowed by other interfaces. Many positive or negative correlations were observed between the interfacial/micellar properties of C8PpEeS and am values, which seems that the surfactant shape dominants the properties of the e-surfactants. In fact, the properties of C8PpEeS are dominated by the dynamic amphipathicity and assisted by the rugby ball shape of the molecules because of both being driven by the dynamic biphasic affinity of the PPO coil in response to the external environment; these findings provide soft interfacial materials specially adapted for surfactant flooding.

Water mediates fertilization in a terrestrial flowering plant.

Water-mediated fertilization is ubiquitous in early land plants. This ancestral mode of fertilization has, however, generally been considered to have been lost during the evolutionary history of terrestrial flowering plants. We investigated reproductive mechanisms in the subtropical ginger Cautleya gracilis (Zingiberaceae), which has two pollen conditions - granular and filiform masses - depending on external conditions. We tested whether rain transformed granular pollen into filiform masses and whether this then promoted pollen-tube growth and fertilization of ovules. Using experimental manipulations in the field we investigated the contribution of water-mediated fertilization to seed production. Rain caused granular pollen to form filiform masses of germinating pollen tubes, which transported sperm to ovules, resulting in fertilization and seed set. Flowers exposed to rain produced significantly more seeds than those protected from the rain, which retained granular pollen. Insect pollination made only a limited contribution to seed set because rainy conditions limited pollinator service. Our results reveal a previously undescribed fertilization mechanism in flowering plants involving water-mediated fertilization stimulated by rain. Water-mediated fertilization is likely to be adaptive in the subtropical monsoon environments in which C. gracilis occurs by ensuring reproductive assurance when persistent rain prevents insect-mediated pollination.

Comparative Study of Conventional/Ethoxylated/Extended n-Alkylsulfate Surfactants.

A series of novel anionic e-surfactants n-C cP pS was molecular designed and synthesized from long-chain fatty alcohols by polypropoxylation and sulfation followed by neutralization. Excellent all-round performance of extended surfactants (e-surfactants) interests us how a simple polypropylene oxide (PPO) spacer has great effects on properties. By a comparative study of conventional/ethoxylated/extended n-alkylsulfate surfactants, we were surprised to find that e-surfactants are in an obvious rugby shape at the air/water surface according to molecular surface area ( am), and it comes down to the intramolecular PPO spacer coiling and surface-induced collapse. On the basis of the interfacial properties of the e-surfactants, it is found that the PPO spacer can provide both hydrophilic and lipophilic contributions to an e-surfactant molecule. The synergism between PPO spacers and alkyl chains indicates that a certain PPO spacer can adjust the contributions in view of different alkyl chain lengths. Therefore, it is both the rugby-shaped molecular geometry of e-surfactants and the dynamic amphipathicity of a PPO spacer that makes e-surfactants behave with excellent interfacial and solution properties for household cleaning. Therefore, this work gives us a hint that the molecular geometry of surfactants plays a vital role in interfacial and solution properties similar to molecular amphipathicity.

The natural sweetener metabolite steviol inhibits the proliferation of human osteosarcoma U2OS cell line.

Steviol is the colonic metabolite of the natural sweetener steviol glycosides. It does not diffuse to the blood and the half maximal inhibitory concentration of steviol is longer compared with that of current chemotherapy agents, including 5-fluorouracil and doxorubicin. The present study demonstrated that steviol inhibits the proliferation of the human osteosarcoma U2OS cell line in a dose- and time-dependent manner, and that the inhibition rate is comparative with that of doxorubicin and 5-fluorouracil. The mechanism of this anticancer activity is also investigated. The results indicated that steviol inhibits U2OS cells through inducing G1 phase cell cycle arrest, downregulating the ability of colony formation via a mitochondrial apoptotic pathway, which was indicated by an increase of the Bax/Bcl-2 ratio and activation of cyclin-dependent kinase inhibitor 1, tumor protein 53 and cyclin-dependent kinase; whereas a Survivin and Caspase 3-independent mechanism was involved. Considering that steviol appears minimally in the plasma during metabolism, and possesses a median lethal dose of 100-fold greater compared with that of 5-fluorouracil, it may become a potential chemotherapy agent.

Influence of substrates on the in vitro kinetics of steviol glucuronidation and interaction between steviol glycosides metabolites and UGT2B7.

Steviol glycosides, a natural sweetener, may perform bioactivities via steviol, their main metabolite in human digestion. The metabolising kinetics, i.e. glucuronidation kinetics and interaction between steviol glycosides or their metabolites and metabolising enzyme, are important for understanding the bioactivity and cytotoxicity. The present study investigated kinetics of steviol glucuronidation in human liver microsome and a recombinant human UDP-glucuronosyltransferases isomer, UGT2B7, along with molecular docking to analyse interaction between UGT2B7 and steviol or glucose. The active pocket of UGT2B7 is consisted of Arg352, Leu347, Lys343, Phe339, Tyr354, Lys355 and Leu353. The influence of stevioside, rebaudioside A, glucose and some chemotherapy reagents on the glucuronidation was also studied. The predicted hepatic clearence suggested that steviol could be classified as high-clearence drug. The steviol glycosides did not affect the glucuronidation of steviol notably.

Inhibitor or promoter? The performance of polysaccharides from Ganoderma lucidum on human tumor cells with different p53 statuses.

Polysaccharides from Ganoderma lucidum (GLPs) have been taken as effective supplements by both healthy people and cancer patients for many years. However, this short survey indicates that instead of inhibiting cancer cell growth, both submerge-cultured intracellular GLP and fruiting body GLP can stimulate the growth of human carcinoma cell lines lacking functional p53, such as HCT-116 p53(-/-), Saos-2, H1299, HL-60, MDA-MB-157. Conversely, the two GLPs inhibit all other assayed cells with functional p53. These results could be an alert since mutational inactivation of the tumor suppressor protein p53 is the most frequent genetic alteration found in human tumors.

Production of a bioactive sweetener steviolbioside via specific hydrolyzing ester linkage of stevioside with a ß-galactosidase.

A ß-galactosidase from Kluyveromyces lactis was found to specifically catalyze hydrolysis of the glycosyl ester linkage of stevioside to yield steviolbioside, a rare sweetener that also exists in Stevia rebaudiana leaves. In a packed bed reactor, a reaction coupling separation was realized and a production yield of steviolbioside reached 90% in 6 h. The hydrolysis product steviolbioside presented higher cytoxicity on human normal cells (hepatocytes cell L02 and intestinal epithelial cell T84) than stevioside did. Comparing to the typical chemotherapy agent, 5-fluorouracil (5-FU), steviolbioside presents much lower cytotoxicity on all assayed human normal cells; it presented notable inhibition on human hepatocarcinoma cell Hep3B, human breast cancer cell MDA-MB-231 and human pancreatic cancer cell BxPC-3. The remarkable inhibition on MDA-MB-231 cells makes steviolbioside a potential remedy for human breast cancer, when steviolbioside is served as a natural sweetener.

Enzymatic transformation of stevioside using a ß-galactosidase from Sulfolobus sp.

Enzymatic hydrolysis and transgalactosylation of stevioside (St) were investigated using a ß-galactosidase from Sulfolobus sp. The hydrolysis yielded steviol as the main final product. Under the optimal transgalactosylation conditions, the highest conversion of stevioside was 87.3% with lactose as a donor, several galactosylated products (St-Gals) were obtained. Metal ions such as Na(+), K(2+), Ca(2+), Ba(2+), Mn(2+) and Mg(2+) (2 mM) did not affect the transgalactosylation activity, while Fe(2+), Fe(3+) and Cu(2+) reduced the transgalactosylation activity of ß-galactosidase to 64%, 33% and 18%, respectively.

Local blockage of EMMPRIN impedes pressure ulcers healing in a rat model.

Excessive extracellular matrix degradation caused by the hyperfunction of matrix metalloproteinases (MMPs) has been implicated in the failure of pressure ulcers healing. EMMPRIN, as a widely expressed protein, has emerged as an important regulator of MMP activity. We hypothesize that EMMPRIN affects the process of pressure ulcer healing by modulating MMP activity. In the rat pressure ulcer model, the expression of EMMPRIN in ulcers detected by Western blot was elevated compared with that observed in normal tissue. To investigate the role of EMMPRIN in regulating ulcer healing, specific antibodies against EMMPRIN were used via direct administration on the pressure ulcer. Local blockage of EMMPRIN resulted in a poor ulcer healing process compared with control ulcers, which was the opposite of our expectation. Furthermore, inhibiting EMMPRIN minimally impacted MMP activity. However, the collagen content in the pressure ulcer was reduced in the EMMPRIN treated group. Angiogenesis and the expression of angiogenic factors in pressure ulcers were also reduced by EMMPRIN local blockage. The results in the present study indicate a novel effect of EMMPRIN in the regulation of pressure ulcer healing by controlling the collagen contents and angiogenesis rather than MMPs activity.

Transglycosylation specificity of glycosyl donors in transglycosylation of stevioside catalysed by cyclodextrin glucanotransferase.

Specificity of glycosyl donors is a critical issue in transglycosylation of stevioside, the main methodology to improve edulcorant quality of stevioside. The most popular glucanotransferase applied in this reaction is cyclodextrin glucanotransferase (CGTase) that catalyses cyclisation, coupling, hydrolysis and disproportionation simultaneously; which results a crosstalk in the glycosyl donors that comes from initial reactants, reaction intermediates as well as side products in parallel reactions. In this work, the specificity of glycosyl donors was studied to understand the transglucosylation pathways with the designed experiments and material balance analysis on the products using a commercial CGTase. It has been found that cyclodextrins and starches provided the best transglucosylation yield, while the assayed mono- and disaccharides were not effective glycosyl donors to stevioside with the CGTase. It is proposed that α- and ß-cyclodextrins performed transglycosylation via coupling to produce intermediates of reducing sugar and followed by disproportionation with stevioside; while starches may perform the transglycosylation combined the cyclodextrins pathway and hydrolysis pathway of starches.

The polysaccharides from fermented Ganoderma lucidum mycelia induced miRNAs regulation in suppressed HepG2 cells.

Medicinal mushroom polysaccharides such as Ganoderma lucidum polysaccharides (GLPs) have been commonly hypothesized to suppress tumor cells proliferation through immune effects. To verify this hypothesis through investigating comprehensive miRNA expression in polysaccharide treated cancer cells, an anticancer mycelia GLP was employed to disclose miRNA differential expression of human hepatocarcinoma cells (HepG2), by using a miRNA microarray assay based on Sanger miR-Base Release 16. The experiment and the analysis result indicates that among the 61 differential expressed miRNAs (p ≤ 0.01), 17 of them were regulated significantly. GLP can inhibit HepG2 cells directly through regulation of hepatocarcinoma genes. A newly found miR-3131 exhibited the strongest upregulation (92-folds, Log2 = 6.53, p = 0.000016). The miRNAs responded synergistically in both hepatocarcinoma and immune-related aspects.

Synthesis and characterization of ampelopsin glucosides using dextransucrase from Leuconostoc mesenteroides B-1299CB4: glucosylation enhancing physicochemical properties.

Novel ampelopsin glucosides (AMPLS-Gs) were enzymatically synthesized and purified using a Sephadex LH-20 column. Each structure of the purified AMPLS-Gs was determined by nuclear magnetic resonance, and the ionic product of AMPLS-G1 was observed at m/z 505 (C21H22O13·Na)⁺ using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. AMPLS-G1 was identified as ampelopsin-4'-O-α-D-glucopyranoside. The optimum condition for AMPLS-G1, determined using response surface methodology, was 70 mM ampelopsin, 150 mM sucrose, and 1 U/mL dextransucrase, which resulted in an AMPLS-G1 yield of 34 g/L. The purified AMPLS-G1 displayed 89-fold increased water solubility and 14.5-fold browning resistance compared to those of AMPLS and competitive inhibition against tyrosinase with a K(i) value of 40.16 µM. This value was smaller than that of AMPLS (K(i)=62.56 µM) and much smaller than that of ß-arbutin (K(i)=514.84 µM), a commercial active ingredient of whitening cosmetics. These results indicate the potential of AMPLS and AMPLS-G1 as superior ingredients for functional cosmetics.

The polysaccharides from Ganoderma lucidum: Are they always inhibitors on human hepatocarcinoma cells?

The antitumor activity of intracellular polysaccharides from submerged fermentation of Ganoderma lucidum was investigated focusing on the inhibition on human liver cancer cells. The polysaccharides inhibited human hepatocarcinoma cell HepG2 during earlier phase with lower dosage but obviously became less functional in later phase regardless of the dosage applied. However, apoptosis of the drugged HepG2 cells appeared in later incubation phase with high dosage, and the apoptosis could be enhanced by supplemental dose of the intracellular polysaccharides. Nevertheless, the intracellular polysaccharides inhibited other human hepatocarcinoma cells such as BEL-7402 and Huh-7 but luckily stimulated human normal liver cell L02 only in a positive dose- and time-dependent manner; so did the sulfated extracellular polysaccharides when it inhibited HepG2 and L02 cells. However, the toxicity of sulfated extracellular polysaccharides to L02 cells can be eliminated by the intracellular polysaccharides.

Nonthermal effect of microwave irradiation in nonaqueous enzymatic esterification.

Microwave has nonthermal effects on enzymatic reactions, mainly caused by the polarities of the solvents and substrates. In this experiment, a model reaction with caprylic acid and butanol that was catalyzed by lipase from Mucor miehei in alkanes or arenes was employed to investigate the nonthermal effect in nonaqueous enzymatic esterification. With the comparison of the esterification carried by conventional heating and consecutive microwave irradiation, the positive nonthermal effect on the initial reaction rates was found substrate concentration-dependent and could be vanished ostensibly when the substrate concentration was over 2.0 mol L(-1). The polar parameter log P well correlates the solvent polarity with the microwave effect, comparing to dielectric constant and assayed solvatochromic solvent polarity parameters. The log P rule presented in conventional heating-enzymatic esterification still fits in the microwaved enzymatic esterification. Alkanes or arenes with higher log P provided positive nonthermal effect in the range of 2 ≤ log P ≤ 4, but yielded a dramatic decrement after log P = 4. Isomers of same log P with higher dielectric constant received stronger positive nonthermal effect. With lower substrate concentration, the total log P of the reaction mixture has no obvious functional relation with the microwave effect.

Inflorescence and flower development in the Hedychieae (Zingiberaceae): Hedychium coccineum Smith.

The inflorescence of Hedychium coccineum Smith is thyrse, and the primary bracts are initiated in a spiral phyllotactic pattern on the sides of the inflorescence dome. Cincinnus primordia are initiated on the flank of the inflorescence apex, in the axils of primary bracts. This primordium subsequently develops a bract and a floral primordium. Then, the floral primordium enlarges, flattens apically, and becomes rounded. Sepals are initiated sequentially from the rounded corner of the primordium ring sepal initiation, and the floral primordium continues to enlarge and produces a ring primordium. Later, this ring primordium separates three common primordia surrounding a central cavity. The adaxial common primordium is the first separation. This primordium produces the posterior petal and the fertile stamen. The remaining two common primordia separate and produce respectively a petal and a petaloid, the inner androecial member. As the flower enlarges, the cavity of the floral cup becomes a rounded-triangular apex; these apices are the sites of outer androecial primordium initiation. The abaxial outer androecial member slightly forms before the two adaxial members develop. But this primordium ceases growth soon after initiation, while the two posterior primordia continue growth to produce the lateral petaloid staminodes. During this stage, gynoecial initiates in the floral cup and continues to grow until extending beyond the labellum.

[Investigation on low power microwave irradiation-assisted enzymatic esterification in organic solvent by fluorescence spectroscopy].

The authors studied the fluorescence change of immobilized lipase from Rhizomucor miehei in the microwave assisted enzymatic esterification of caprylic acid and butanol in organic medium by investigating the fluorescence spectra in solvent or aqueous buffer after incubating the lipase with the solvent, caprylic acid and butanol under microwave irradiation, respectively. A comparison was made with the conventional heated enzymatic esterification in the solvents. Both of the heating modes, the microwave irradiation and conventional heating, can enhance the fluorescence intensity without shifting the emission wavelength of the lipase. In the circumstance that the irradiation can accelerate the esterification, the irradiation can enhance the exposure of the lipase protein molecules in the aqueous environment after incubating the lipase with solvents or the substrates. The effect of the reaction mixture on the fluorescence intensity was dominated by the solvents. The trend of the plot of log P versus the initial reaction rate was similar to that of log P versus fluorescence intensity of lipase in aqueous buffer after esterification; but was different from that of log P versus fluorescence intensity of lipase in organic medium.

Identification and expression of floral organ homeotic genes from Alpinia oblongifolia (Zingiberaceae).

Current understanding of the classical ABC model of floral development has provided a new set of characters to evaluate floral evolution. However, what is still lacking is a clear assessment of this genetic program across monocots. Here, to investigate the evolution of members of class A and B genes in monocots, we report the sequence characteristic and transcript expression of three new MADS-box genes in Alpinia oblongifolia Hayata. Sequence and phylogenetic analysis reveals that these genes are FUL-like and AP3-like. Therefore, they were termed AoFL1, AoFL2 and AoAP3. AoFL1 contains the FUL motif, but AoFL2 lacks this motif. Their expression revealed by in situ hybridization may reflect the ancestral function of FUL-like genes in the specification of inflorescence and floral meristems. The AoAP3 gene contains two conserved motifs, the PI-derived and paleoAP3 motifs. The AoAP3 transcripts located to the corolla and stamen, and hybridization signals were detected in the central whorl. These expression patterns suggest that the functions of homologous organ identity genes are diversified in A. oblongifolia. The implications of these findings on the conservation of homologous gene function are discussed.

1-Carboxy-methyl-2-ethyl-4-methyl-1H-imidazol-3-ium chloride monohydrate.

In the title compound, C(8)H(13)N(2)O(2) (+)·Cl(-)·H(2)O, the methyl C atom of the ethyl group is slightly out of the imidazole plane, with an N-C(ring)-C-C torsion angle of -15.1 (2)°. In the crystal structure, there are strong inter-molecular hydrogen-bonding inter-actions between the solvent water mol-ecule, the free chloride anion and the organic cation, resulting in a two-dimensional supra-molecular network in the ab plane.