中草药化妆品的研究与开发

对传统中草药在古代化妆品和现代天然日化领域的应用进行了阐述,提出了中草药在现代日化领域应用的思路.     

A bioluminescence assay for DNA methyltransferase activity based on methylation-resistant cleavage

DNA methyltransferase (MTase) is a kind of important regulatory factor in various biological processes. Current methods to investigate DNA MTase activity are still limited in the sensitivity and/or generality. Therefore, developing methods with high sensitivity and improved generality is needed. Here, we develop a new bioluminescence strategy based on methylation-resistant cleavage and protein expression in vitro to detect DNA MTase activity. In the strategy, Dam MTase was used as a model enzyme and MboI as the methylation-resistant endonuclease, and luciferase reporter DNA (LR-DNA) was used as their action target. Because the completely methylated LR-DNA could be expressed as detectable luciferase, Dam MTase activity was quantified by measuring the luminescence intensity of the expressed luciferase. The assay provides a very low detection limit (0.08 U/ml) as well as a wide linear range (0.2-100 U/ml). Besides, the analysis mode has improved generality and could be extended to the detection of other DNA MTases and the corresponding inhibitor screening.     

Peripheral oestrogen metabolism in postmenopausal women with or without breast cancer: the role of dietary lipids and growth factors

Studies we have carried out have revealed significant differences in oestrogen production and metabolism between normal women and postmenopausal women with breast cancer. The free, biologically available fraction of oestradiol is elevated in plasma from women with breast cancer and we have found that metabolic clearance rates and production rates of oestradiol are also increased. In vitro studies have suggested that lipids can influence the distribution of sex steroids in plasma and we have therefore examined the effect of dietary lipids on the distribution of sex steroids in plasma in vivo. Consumption of a meal with a high saturated fat content or the oral or i.v. administration of "Intralipid", a stabilised emulsion of soya bean oil that is high in unsaturated free fatty acids, had little effect on the available fractions of oestradiol in plasma. However, results from a preliminary study suggest that long-term changes in dietary fat intake can alter the distribution of steroids in plasma. It is concluded that dietary lipids may influence the availability of sex steroids to tissues. Such a mechanism could account for the significant correlation that has been found between dietary fat consumption and the incidence of breast cancer on a world-wide basis.     

北疆高产棉花密度与打顶时序调控的生态位适宜度研究

以北疆棉区高产 (2 0 0 0kg·hm-2 )棉花 (G .hirsutumL .)为研究对象 ,引进生态位适宜度理论对受密度和打顶时序调控的高产棉花生态位适宜度进行了研究。经果表明 ,在密度梯度上 ,随密度增加棉花生态位适宜度值增加。 1 5 0× 1 0 3 株·hm-2 密度下 ,分次打顶降低了生态位适宜度 ,导致减产 ;在高密度种植条件下 ,分期打顶能提高生态位适宜度 ,有利于提高产量。在 2 2 5× 1 0 3 和 30 0× 1 0 3 株·hm-2 密度条件下 ,与同密度下 1次打顶 (7/5 )相比 ,2次打顶增产 4 5 %和 1 1 3%,3次打顶增产 7 5 %和 5 9%。 1 5 0× 1 0 3 株·hm-2 密度下 ,棉田苗蕾期LAI较小、漏光损失大 ,光合势低 ,是实现超高产的主要限制因子 ,花铃期的分期打顶导致减产。在 2 2 5× 1 0 3 和 30 0× 1 0 3 株·hm-2 密度条件下 ,棉花苗蕾期LAI增加 ,分期打顶保证了花铃期较适宜的LAI ,提高了棉花生态位适宜度 ,有利于提高产量 ;1次打顶处理 (7月 5日 )比本区生产上的打顶时间 (7月 1 0日左右 )提早了 5d左右 ,使高密度棉花群体LAI的发展受到了一定程度地限制 ,避免了因密度高群体透光条件的恶化而降低了其生态位适宜度值 ,造成减产损失。     

A chimeric protein of simian immunodeficiency virus envelope glycoprotein gp140 and Escherichia coli aspartate transcarbamoylase

The envelope glycoproteins of the human immunodeficiency virus and the related simian immunodeficiency virus (SIV) mediate viral entry into host cells by fusing viral and target cell membranes. We have reported expression, purification, and characterization of gp140 (also called gp160e), the soluble, trimeric ectodomain of the SIV envelope glycoprotein, gp160 (B. Chen et al., J. Biol. Chem. 275:34946-34953, 2000). We have now expressed and purified chimeric proteins of SIV gp140 and its variants with the catalytic subunit (C) of Escherichia coli aspartate transcarbamoylase (ATCase). The fusion proteins (SIV gp140-ATC) bind viral receptor CD4 and a number of monoclonal antibodies specific for SIV gp140. The chimeric molecule also has ATCase activity, which requires trimerization of the ATCase C chains. Thus, the fusion protein is trimeric. When ATCase regulatory subunit dimers (R(2)) are added, the fusion protein assembles into dimers of trimers as expected from the structure of C(6)R(6) ATCase. Negative-stain electron microscopy reveals spikey features of both SIV gp140 and SIV gp140-ATC. The production of the fusion proteins may enhance the possibilities for structure determination of the envelope glycoprotein either by electron cryomicroscopy or X-ray crystallography.     

Apobec-1 Increases Cyclooxygenase-2 and Aggravates Injury in Oxygen-Deprived Neurogenic Cells and Middle Cerebral Artery Occlusion Rats

Given that cyclooxygenase-2 (COX-2) plays a crucial role during cerebral ischemia and Apobec-1 is a critical regulator of COX-2 mRNA stabilization in gastrointestinal settings, the correlation of COX-2 and Apobec-1 was investigated in neurogenic cells and rat model of cerebral ischemia. After neurogenic SH-SY5Y, NG108-15 and PC12 cells were exposed to oxygen-glucose deprivation, cell viability, LDH leakage and Apobec-1 expression were determined. The effect of Apobec-1 overexpression on injury severity of oxygen-glucose deprivation, COX-2 expression, C-to-U editing of COX-2 mRNA were measured in vitro. Then the correlation of Apobec-1 level and injury severity was analyzed in cells with oxygen-glucose deprivation and in rats with middle cerebral artery occlusion. Apobec-1 expression was elevated along with upregulation of COX-2 and injury severity of oxygen-glucose deprivation in the three cell lines. Apobec-1 overexpression aggravated injury of oxygen-glucose deprivation in vitro and could be correlated to injury severity in vivo. Meanwhile, Apobec-1 increased COX-2 expression and COX-2 mRNA stabilization in neurogenic cells, and failed to catalyze C-to-U editing of COX-2 mRNA. Apobec-1 could upregulate COX-2 expression in neurogenic cells by stabilizing COX-2 mRNA, and might aggravate injury of oxygen-glucose deprivation in neurogenic cells as well as in rats with cerebral ischemia.     

Enhanced insulin sensitivity using electroacupuncture on bilateral Zusanli acupoints (ST 36) in rats

In this study, intravenous glucose tolerance test (ivGTT) and insulin challenge test (ICT) were applied to evaluate the influence of electroacupuncture (EA) on insulin sensitivity in rats. Firstly, hypoglycemic activity was confirmed on normal Wistar rats (36+/-12%) and streptozotocin (STZ)-induced diabetic rats (13+/-8%) after 60 min of 15 Hz EA on bilateral Zusanli acupoints. The rats were divided into the experiment group (EG) and control group (CG) randomly. After fasting, plasma glucose and insulin levels were assayed in the normal Wistar rats undergoing ivGTT. Plasma glucose levels and hypoglycemic activity were also evaluated in the normal Wistar rats and STZ diabetic rats during ICT. As the data showed, EA improved the glucose tolerance from 15 to 90 min (p<0.005 compared with the plasma glucose levels of the CG) during ivGTT. In addition, significant improvement in the Homeostasis Model Assessment (HOMA) index was found in the EG from 15 to 90 min (p<0.005 compared with the CG). More hypoglycemic activity was achieved in normal Wistar and STZ diabetic rats in the EG than in the CG (from 30 to 60 min) during ICT. In conclusion, the results suggest that 15 Hz EA at bilateral Zusanli acupoints improved glucose tolerance. Thus, EA should be considered as an alternative method for improving insulin sensitivity and/or increase insulin-hypoglycemic activity in rats.