Development, characterization and in vitro bile salts binding capacity of selenium nanoparticles stabilized by soybean polypeptides.

The paper presents the positive effect of soybean polypeptides (SP) on the stability and the potential hypolipidemic effect of selenium nanoparticles (SeNPs). After preparing SeNPs, SP with different molecular weight were introduced to stabilize SeNPs. We found that the SP with molecular weight >10 kDa (SP5) had the best stabilizing effect on SeNPs. We inferred that the steric resistance resulting from the long chains of SP5 protected SeNPs from collision-mediated aggregation, and the electrostatic repulsions between SP5 and SeNPs also played a positive role in stabilizing SeNPs. The as-prepared SP5-SeNPs were spherical, amorphous and zero valent. It was proved that SeNPs were bound with SP5 through O- and N- groups in SP5, and the main forces were hydrogen bonds and van der Waals forces. The bile salts binding assay showed that the SP5-SeNPs exhibited a high binding capacity to bile salts, which indicated their potential in hypolipidemic application.

A facile macroporous resin-based method for separation of yellow and orange Monascus pigments.

The yellow Monascus pigments (YMPs) named monascin and ankaflavin and the orange Monascus pigments (OMPs) named rubropunctatin and monascorubrin are two groups of bioactive components in a mixture state in the Monascus fermented products. In order to separate these two groups of bioactive pigments, a facile macroporous resin-based method was developed. The weak-polar resin CAD-40 was selected from the seven tested macroporous resins as it revealed better properties for the adsorption and desorption of the YMPs and OMPs. Then, CAD-40 resin was used for column-chromatographic separation. After eluted by 4 bed volumes of ethanol, the yellow group (monascin and ankaflavin) and the orange group (rubropunctatin and monascorubrin) were successfully separated and purified, with an increased content from 49.3% and 44.2% in the crude pigment extract to 85.2% and 83.0% in the final products, respectively. This method would be helpful for the large-scale separation and purification of Monascus pigment products with specific bioactivity.

Inducible expression of human angiostatin by AOXI promoter in P. pastoris using high-density cell culture.

A high-density cell culture method was successfully established in P. pastoris with the alcohol oxidase I (AOXI) promoter in order to produce large quantities of recombinant human angiostatin (AS) which has been reported to have antiangiogenic activity. A preliminary study on fermentation conditions in shaking flasks indicated that adequacy of biomass is beneficial to obtain more products. The fermentation was carried out in a 10 l bioreactor with 5 l modified growth medium recommended by Invitrogen at 30 degrees C. The cells were first grown in glycerol-PTM4 trace salts for 24 h. When the cell density reached A(600) = 125, methanol-PTM4 trace salts was added to induce the expression of AS. During the fermentation, dissolved oxygen level was maintained at 20-30%, pH was controlled at 5 by the addition of 7 M NH(4)OH and the biomass was maintained at about A(600) = 200. After 60 h of induction, the secreted AS was 153 mg/l. The recombinant AS inhibited the angiogenesis on CAM and suppressed the growth of B16 melanoma in C57BL/6J mice (P \0.01).