•Created a new amphiphilic emulsifier based on Acacia Seyal hydrophobic peptides of casein.•The new emulsifier demonstrated improved emulsification properties.•The processing for preparing the new emulsifier is “natural”.A novel A. seyal gum-based emulsifier was obtained with dramatically elevated emulsifying properties comparing to A. seyal polysaccharide, by hydrophobically-modifying Acacia seyal polysaccharide with casein hydrophobic peptide (CHP) through dry-state Maillard reaction. The formation of CHP-A. seyal polysaccharide conjugate (SeyCHP) was confirmed with high performance size exclusion chromatography (HPSEC) and determination of graft of degree. The stability of the emulsion of canola oil in water stabilized with the conjugates was investigated. The results revealed that the emulsifying capacities of the conjugates were improved up to 46 times of that of Acacia seyal polysaccharide, which is close to that of Acacia senegal gum; and the emulsion stability can be enhanced up to 21 times of that of Acacia seyal polysaccharide. This indicates that covalent modification with hydrophobic peptide to hydrophilic polysaccharide may provide an efficient strategy to improve the emulsifying properties of hydrophilic polysaccharides.Covalent linking casein hydrophobic peptide to A. seyal polysaccharide dramatically elevated the emulsifying properties of A. seyal polysaccharides.Download high-res image (352KB)Download full-size image

•The β-galactosidase catalyzes specific hydrolyzing stevioside to steviolbioside.•Reaction coupling separation was realized in a packed bed reactor.•Steviolbioside inhibits human breast cancer cells as a natural sweetener.A β-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.

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.

Enzymatic hydrolysis and transgalactosylation of stevioside (St) were investigated using a β-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+, K2+, Ca2+, Ba2+, Mn2+ and Mg2+ (2 mM) did not affect the transgalactosylation activity, while Fe2+, Fe3+ and Cu2+ reduced the transgalactosylation activity of β-galactosidase to 64%, 33% and 18%, respectively.

•First report about polysaccharides interrupting the hepatocarcinoma related miRNA expression.•61 miRNAs were regulated significantly in miRNA expression of HepG2 suppressed by the GLP.•Differential expressions were observed in both of hepatocarcinoma and immune related miRNA.•miR-3131 with unknown function presented strong upregulation (92-folds, Log 2 = 6.53, p = 0.000016).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, Log 2 = 6.53, p = 0.000016). The miRNAs responded synergistically in both hepatocarcinoma and immune-related aspects.

The extracellular polysaccharides from Ganoderma lucidum possess low molecular weight and are mainly composed of (1 → 3)/(1 → 6) linked-α-glucan and (1 → 3)/(1 → 6) linked-α-galactose. In the present study, conformations of the polysaccharides were simulated and investigated using Discovery studio 2.5. Their sulfated derivatives were also taken into account. The simulation was performed using CHARMM force field. The results show that the polysaccharides exist as random coil conformations, while the sulfated derivatives adopt more extensive and stiffer conformations in most cases. In addition, the molecular docking between polysaccharide and human serum albumin (HSA) was also investigated using ZDOCK module in Discovery studio 2.5. It is shown that the unmodified polysaccharide possesses higher affinity with HSA than the sulfated derivatives do due to its higher ZDOCK score.

Methylated nucleosides play an important role in DNA/RNA function, and may affect republication by interrupting the base-pairing and base-stacking. In order to investigate the effect of methylation on the interaction between nucleic acid bases, this work presents the hydrogen-bonding and stacking interactions between 5-methylcytosine and guanine (G), cytosine (C) and G, 1-methyladenine and thymine (T), as well as adenine and T. Geometry optimization and potential energy surface scan have been performed for the involved complexes by MP2 calculations. The interaction energies, which were corrected for the basis-set superposition error by the full Boys–Bernardi counterpoise correction scheme, were used to evaluate the interaction intensity of these nucleic acid bases. The atoms in molecules theory and natural bond orbital analysis have been performed to study the hydrogen bonds in these complexes. The result shows that the methyl substitute contributes the stability to these complexes because it enhances either the hydrogen bonding or the staking interaction between nucleic acid bases studied.

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.

The nonthermal effect of microwave irradiation (MI) on the 1,3-specificity in the enzymatic esterification of glycerol and caprylic acid in the presence or absence of the solvent was studied, respectively. Comparison on the 1,3-specificity was made between reactions driven by low power consecutive microwave irradiation and conventional heating (CH). For the four assayed lipases, the microwave irradiation did not change but weaken the lipase's 1,3-specificity regardless the form of the lipase employed in the solvent-free medium. Novozyme 435 was then selected for the further investigation to reveal the changing of the 1,3-specificity resulted by varying reaction parameters under consecutive microwave irradiation and conventional heating, respectively. The influence of the molar ratio of the substrates, the initial water dosage, the solvents with different log P, and the power of the microwave irradiation on the 1,3-specificity was investigated. In any circumstance assayed, the consecutive microwave irradiation did not change but weaken the 1,3-specificity of Novozyme 435 in the presence or absence of the solvent.

•Microwave irradiation speeded transglycosylation of stevioside up to 20-folds.•Microwave affects the transglycosylation pathway of α/β- cyclodextrin remarkably.•Microwave does not affect the transglycosylation pathway of starches dramatically.•Hydrolysis instead of enzyme deactivation caused the quick reaction equilibrium.Microwave irradiation may alternate reaction specifity in multipath reactions. In this experiment, transglycosylation of stevioside with starches or α/β-cyclodextrin (CD) reached reaction equilibrium only in 3 min under low power microwave irradiation, when 10 U/g stevioside of a CGTase was applied. Microwave irradiation does not dramatically affect the transglycosylation pathway of the starches with stevioside, but it remarkably affects the transglycosylation pathway of α/β-CD onto stevioside. Unlike the case under conventional heating, the transformation between α-CD and β-CD was dramatically declined by microwave. With α/β-cyclodextrins as glycosyl donor, highly grafted products were diminished under microwave irradiation. Gelatinized starch produced much more cyclodextrins than hydrolyzed starch did, which made higher stevioside conversion with gelatinized starch.The reaction was accelerated 20 times by microwave irradiation compared to that in the conventional heating procedure.Download full-size image

•Hydrophilic properties of assayed polymers are proportional to the water absorption.•All assayed polymers enhanced water absorption at concentrations higher than 0.2%.•The mechanical strengths enhancing happened with acceleration of initial hydration.•The decrease of mechanical strengths happened with retard of the hydration.Polymers have been used to modulate mechanical strengths and water absorption of construction or modeling materials as like gypsum. To understand the structure–performance relationship of polymers in hydration and properties of gypsum plaster, several designed carboxyl polyether sulfonates were investigated with comparison of some commercial polymers. It is found that bending strength of the hardened β-hemihydrate plaster is inversely proportional to number of carboxyl groups in the polymer that retards hydration. The mechanical strengths enhancement is coincident with acceleration of initial hydration, while decrease of mechanical strengths happened with retard of the hydration.Download full-size image