10升气升环流式生物反应器培养紫草细胞

本文采用自行设计研制的10升气升环流式生物反应器培养紫草细胞,培养周期34d．前14d为细胞生长培养,细胞生长呈正常的S型曲线,细胞增长到原细胞接人量的4倍．后20d为紫草色素生产培养,细胞增长到32倍。整个周期每升培养液可生产紫草色素0．6g,在反应器中,培养液pH值的变化与细胞生长呈正相关,与紫草色素的形成呈负相关,pH值变化规律可用于监测紫草细胞在生物反应器的生长和色素形成．     

Improved cosmetic activity by optimizing the Lithospermum erythrorhizon extraction process

This study was conducted to expand the use of Lithospermum erythrorhizon, which is a good source of natural dye, in skin whitening and immune activation cosmetics. The goal was to provide cosmeceutical data about the extraction yield and shikonin contents of this plant by optimizing the ultrasonic extraction and high pressure extraction conditions. Under optimal extraction conditions, which consisted of 500 MPa for 60 min and 120 kHz for 90 min, 27.49 and 3.19 % (w/w) of the highest extraction yield and shikonin contents were obtained, compared to 16.32 and 1.81 % from a conventional ethanol extract (EE) control. Hyaluronidase inhibition activity was measured as 44.24 % after adding 1.0 mg/ml of ethanol extract, but it was as high as 64.19 % when using extract produced by ultrasonication with high pressure extraction (UE + HPE). The MMP-1 expression levels from skin fibroblast cells (CCD-986sk) treated with or without UV irradiation were also lowered by as much as 110.6 % after adding 1.0 mg/ml of the UE + HPE extract, relative to 126.9 % from the EE. After UVA exposure, prostaglandin E2 production from RAW 264.7 was also lower, at 110.6 %, which also indicates that the extract from the UE + HPE process enhanced skin immune activation activities. For the skin whitening activity, tyrosinase inhibitory activity was observed at 67.15 % in the HPE + UE extract, which was ca. 20 % higher than that of the EE extract (57.48 %). To reduce melanin production in Clone M-3 cells, 79.5 % of the melanin production was estimated after adding 1.0 mg/ml of the UE + HPE extract compared to that of the control (no treatment), which was similar to the 77.4 % result found in an ascorbic acid positive control. The highest shikonin secretion was conclusively obtained under the optimal conditions and resulted in a significant improvement of the cosmetic activities of L. erythrorhizon extracts.     

Overproduction of an α-Amylase/Glucoamylase Fusion Protein in Aspergillus oryzae Using a High Expression Vector

The systemic immune response against orally administered antigens is suppressed (oral tolerance), and this has been postulated to avoid excess immunity against dietary constituents which are present in large amounts in the gastrointestinal tract. Taking into consideration that such orally administered protein antigens are subjected to enzymatic degradation in the gastrointestinal tract, we examined whether an enzymatic digest of milk proteins could induce oral tolerance. A tryptic digest of casein, containing mainly fragments smaller than 6000 Da, was fed to mice as a constituent of their diet. Mice fed with the casein-digest diet responded poorly to subsequent immunization with casein, indicating that oral tolerance to casein was induced in these animals. The results suggest the presence of immunosuppressive fragment(s) in the casein digest, which may be of use for preventing milk allergy.     

用吸附法固定化培养紫草细胞

采用生物活性载体 ,通过吸附固定化方式 ,结合液体石蜡原位萃取技术 ,培养紫草细胞。测定了细胞生长、底物消耗和产物合成的动力学 ,紫草宁产率为 0 .916 g/g干重细胞和 0 .95 3g/g干重接种细胞 ,分别为悬浮培养的 12 .7倍和 6 .3倍。同时 ,对吸附与包埋固定化方法进行了综合比较 ,探讨了吸附固定化方法的应用前景。     

Enzyme activity and shikonin production in Lithospermum erythrorhizon cell cultures

The activities of the biosynthetic enzmes phenylalanine ammonia lyase (PAL) and 3-hydroxy-3-methylglutaryl-CoA-reductase (HMGR) were measured in cells transferred from growth to production medium in a two-stage batch culture. It was found that both these enzymes showed transient increases, PAL (three- to fourfold) and HMGR (two- to four-fold), at or near the point of exhaustion of nitrogen source (NO(3)). Production of shikonin derivatives also started at this time. The addition of excess nitrate to the medium shortly before nitrate exhaustion (days 6-8) markedly reduced the final product yield (by 70-80%) while addition of excess nitrate in the later stationary growth phase (days 14-16) had no significant effect. When the production rate of shikonin derivatives was correlated with PAL activity, it was observed that production rate is very low (less than 1 mg/L . day) at low levels of PAL activity (below 0.1 unit/mg protein). Once a threshold level of PAL activity (about 0.15 unit/mg protein) is reached, the biosynthetic rate of shikonin derivatives increases. Such a relationship could not be deduced for HMGR activity. It was concluded that the production of shikonin derivatives may be limited at the phenylalanine deaminating step at low levels of PAL activity.