Immune-enhancing effects of three kinds of purple sweet potato polysaccharides (PSPPs) including water-soluble polysaccharide (WSP), dilute alkali-soluble polysaccharide (DASP) and concentrated alkali-soluble polysaccharide (CASP) were evaluated. Scanning electron microscope analysis showed that all PSPPs could stimulate the formation of microvilli-like structures in cellular surfaces, which was possibly related to activation of macrophages. Neutral red uptake assay showed that PSPPs could increase the phagocytic activity of cells. High dose (400 μg/mL) of PSPPs could notably augment the level of nitric oxide (NO). ELISA analysis revealed that 200 and 400 μg/mL of PSPPs distinctly elevated the production of IL-1β. Cells received 200 and 400 μg/mL of WSP as well as 400 μg/mL of DASP exhibited higher level of IL-6. Results of animal experiments showed that WSP treatment (400 mg/kg) could promote the secretions of IgA, IgG, IgM and sIgA in both normal and immunosuppressed mice. Moreover, CASP treatment (400 mg/kg) elevated the production of IgM in the serum of normal and immunosuppressive mice, while DASP (400 mg/kg) only improved the secretion of IgM in normal mice. In summary, all three polysaccharides can stimulate immune responses of macrophages and positively regulate adaptive immunity by enhancing the production of immunoglobulins in mice.

Compared with the traditional method, the microwave assisted method can greatly shorten the reaction time of hydroxypropyl starch and improve product quality. The microwave assisted conditions and physicochemical properties of natural corn starch were studied. Response surface methodology was used to optimize the reaction conditions of three-level-three-factorial center composite design. The optimum parameters were as follows: the additive amount of propylene oxide was 8%, the radiation time was 6.08 min, and the microwave power was 303.43 W. The optimal degree of substitution (DS) of hydroxypropyl starch was determined by the optimal conditions predicted by RSM, which was 0.0729 mg/g. The analysis of physicochemical properties showed that with the increase of the DS of starch derivatives, the transparency (4% to 8.81%), the volume ratio of the condensing volume (21.11% to 33.11%), the hydrophilic (0.73 g/g to 2.46 g/g), and the hydrophobicity (0.67 g/g to 1.01 g/g), and the water evolution rate (46.91% to 36.16%) decreased. Fourier transform infrared spectroscopy showed that the enhancement of peak intensity at 1149 cm-1 indicated the successful introduction of hydroxypropyl group. Scanning electron microscopy showed that the surface morphology of corn starch was affected to some extent. The modification did not change the crystalline type of starch, which was still A type.

The effect of arabinoxylan (AX) combined with β-glucan and xyloglucan on lipid metabolism by regulating bile acids and gut microbiota was investigated in mice fed with high-fat diet. Fifty male ICR/KM mice were randomly divided into five groups: control diet (CON) group, high-fat diet (HFD) group, high-fat diet with AX (HFAX) group, high-fat diet with AX and β-glucan (HFAB) group, and high-fat diet with AX and xyloglucan (HFAG) group. After 8 weeks of feeding, the mice were sacrificed and samples were collected. In contrast to CON, HFD disturbed lipid metabolism, bile acids, and gut microbiota in mice. Mice in HFD group had increase in weight, blood lipids and liver fat, and circulating bile acid as well as abnormal liver tissue morphology and disordered gut microbiota. Compared with HFD, HFAB and HFAG mice had reduced body weight and cholesterol and triglyceride levels; Fxr was activated, Cyp7a1 was inhibited to reduce bile acids, the microbial species diversity increased, the number of beneficial bacteria increased, and the number of conditional pathogenic bacteria decreased. HFAG uniquely activated intestinal bile acid receptors (Fxr and Tgr5) and increased the abundance of Bacteroidetes and Akkermansia. In summary, the effect of AX compounded glucans (β-glucan or xyloglucan) on lipid metabolism was better than that of single AX by regulating bile acid metabolism and gut microbiota possibly due to the more complex chemical structure of combined polysaccharides.

Arabinoxylan (AX) has many beneficial health effects that are closely related to its structural characteristics. The current study aimed to investigate the effects of molecular weight (Mw) and degree of substitution (DS) on the antioxidant and hypoglycemic activities of triticale bran AX and its hydrolysates in vitro. At low and similar Mw, the antioxidant activity of AX was inversely proportional to its DS. When DS was close, the antioxidant activity of AX was inversely proportional to its Mw at high DS, but the opposite result was found at low DS. As for the hypoglycemic performance, when DS was similar, the hypoglycemic activity of AX was proportional to its Mw. At low and similar Mw, the α-glucosidase inhibitory ability and glucose adsorption ability of AX was positively correlated with DS, whereas the α-amylase inhibitory ability and glucose delayed absorption ability showed the opposite results. Mw and DS had significant effects on the antioxidant and hypoglycemic activities of AX, and these two factors often need to be combined to explain the varied effects under different conditions.

Skeletal muscle development and growth regulatory mechanism is the focus of both animal genetics and medicine. The recent studies indicate that covalently closed circular RNAs (circRNAs) also play important role on muscle development through sequestering specific miRNAs. The present study was conducted to determine the functional roles of circZfp609, a recently identified circRNA, in the regulation of myogenesis in mouse myoblast cell line (C2C12). circZfp609 is predicted to has binding sites of miR-194-5p. circZfp609 knockdown increased the expression of Myf5 and MyoG, which indicated that circZfp609 suppressed myogenic differentiation. Via a luciferase screening assay, circZfp609 is observed to sponge to miR-194-5p with four potential binding sites. Specifically, we show that circZfp609 can sponge miR-194-5p to sequester its inhibition on BCLAF1 so as to repress the myogenic differentiation. Modulation of circZfp609 expression in muscle tissue may emerge as a potential target in breeding strategies attempting to control muscle development.

Protein fibrils drive the onset and progression of many diseases in a prion-like manner, i.e. they transcellular propagate through the extracellular space to health cells to initiate toxic aggregation as seeds. The conversion of native α-synuclein into filamentous aggregates in Lewy bodies is a hallmark of Parkinson's disease (PD). Copper and iron ions accumulate in PD brains, however, whether they influence the prion-like propagation of α-synuclein remain unclear. Here, we reported that copper/iron ions accelerate prion-like propagation of α-synuclein fibrils by promoting cellular internalization of α-synuclein fibrils, intracellular α-synuclein aggregation and the subsequent release of mature fibrils to the extracellular space to induce further propagation. Mechanistically, copper/iron ions enhanced α-synuclein fibrils internalization was mediated by negatively charged membrane heparan sulfate proteoglycans (HSPGs). α-Synuclein fibrils formed in the presence of copper/iron ions were more cytotoxic, causing increased ROS production, cell apoptosis, and shortened the lifespan of a C. elegans PD model overexpressing human α-synuclein. Notably, these deleterious effects were ameliorated by two clinically used chelators, triethylenetetramine and deferiprone. Together, our results suggest a new role for heavy metal ions, e.g. copper and iron, in the pathogenesis of PD through accelerating prion-like propagation of α-synuclein fibrils.

The physicochemical and digestive properties of acetylated corn starch with different degrees of substitution were studied, which were prepared by microwave pretreatment and acetate esterification. Native corn starch-wheat noodles, acetylated corn starch-wheat flour noodles and native wheat noodles were prepared and their properties were compared. The results showed that the transparency, condensation volume ratio, hydrophilicity and lipophilicity of modified corn starch increased with increasing of substitution degree, which were 4.0% to 12.1%, 21.11% to 31.78%, 0.73 g/g to 0.91 g/g and 0.66 g/g to 0.88 g/g, respectively and the rate of water evolution decreased from 44.9% to 33.3%. Fourier transform infrared spectroscopy showed that acetyl group was successfully introduced. Scanning electron microscopy showed that microwave pretreatment and group introduction made the surface of starch granules locally porous and rough. Differential scanning calorimetry showed lower onset temperature, peak temperature, conclusion temperature and enthalpy than native corn starch, which proved that acetylated corn starch reduced the content of rapidly digestion starch and increased the content of slow digestible starch and resistant starch. At the same time, the results showed that the color, texture and tensile properties of noodles with acetylated corn starch were improved. It showed that acetylated corn starch prepared by microwave pretreatment and acetate esterification had certain application prospects.

The starch/polyvinyl alcohol/graphene oxide composite film was prepared by casting method by adding GO to starch/PVA matrix. The effects of GO with different concentrations on the performance of the composite film were studied. With the increase of GO concentration, the thickness increased, the tensile strength increased first and then decreased. When the concentration of GO reached 2 mg/ml, the tensile strength was 25.28 MPa reaching the maximum. The increase of GO concentration caused the enhancement of film's moisture resistance. Through FTIR, SEM and TGA analysis, it was found that the addition of GO did not change the composition of the film, but it could change the phenomenon of matrix agglomeration and improve the thermal stability of the film. The preparation of composite films by adding GO could improve the properties, expand the application of nanomaterials in the food packaging field, and expand the research of biodegradable composite films.