植物选择标记基因hpt在大肠杆菌中的融合表达、纯化及活性测定

为对hpt基因编码蛋白进行的安全性评价，建立一种简便、高效的体外微生物表达体系，以获得大量的HPT蛋白，将用于植物转化的hpt基因的全编码序列克隆到原核表达载体pGEX4T-3上，在E．coli BL21中进行诱导表达，所得融合蛋白主要以包涵体的形式存在，且与Glutathione Sephrose 4B纯化介质的结合率不高。后经优化诱导表达的各种条件，成功地获得了可溶性的融合蛋白，该蛋白具有明显的生物活性。经Glutathione Sephrose 4B亲和层析，所得蛋白纯度＞95％。动物实验显示，融合蛋白还具有良好的免疫原性，免疫家兔后可诱导产生高滴度的抗体(＞1：10000)。ELISA及Western blotting检测进一步证实了所获纯化蛋白及其抗体的特性。这为深入进行HPT蛋白的安全性评价打下了良好的基础。     

QUANTIFICATION OF YEAST FLOCCULATION

A sedimentation method based in the Helm's flocculation test was improved. In this method, all steps were standardised: initial cell concentration, agitation, sampling and determination of settled cells. The results obtained with the sedimentation test do not differ significantly (P = 0.05) from those obtained with the Stratford test; besides, the precision of the two methods do not differ significantly (P = 0.05). The results presented clearly demonstrated that the method improved in this work is rigorous for quantification of yeast flocculation and allows the differentiation of flocculation ability of the strains. The respective micro-flocculation tests were also compared; Stratford micro-flocculation test was selected as producing the most meaningful results.     

一种以面向对象及形式化技术为基础的严格的软件开发方法

随着软件开发规模的迅速扩大，目前流行的软件开发方法（包括当前的软件工程法）已难以满足开发实践的要求，实践要求在软件开发方法学上能有新的进展。鉴于此，本文在面向对象及开式化方法的基础上，系统地提出了一种严格的软件开发方法，力图使开发者的创造性及开发环境的自动化能力都得到充分发挥，使软件开发能适应形势的需要     

Screening survey of deoxynivalenol in beer from the European market by an enzyme-linked immunosorbent assay

Deoxynivalenol (DON) was analysed in 313 beer samples collected from the European retail market using a commercially available immunoassay kit (enzyme-linked immunosorbent assay, ELISA). The incidence rate was about 87%, while most samples (73%) had contamination levels lower than 20 ng ml^-1. The contamination ranged between 4.0 and 56.7 ng ml^-1, with an average of 13.5 ng ml^-1. A statistically significant correlation between alcohol levels and DON contamination was found, as well as a significant difference between bottom, top and spontaneous fermenting beers. Twenty-seven beer samples were compared using a second ELISA kit and a good correlation was obtained between the two kits (r = 0.93). Although when compared with gas chromatography-mass spectrometry the ELISA tended to overestimate the results, a good correlation (r = 0.94) between the two methods was observed. Monitoring of DON in beer is important considering that DON production is dependent on the weather and that it can contribute significantly to the tolerable daily intake of DON, especially for frequent beer consumers.     

应用免疫印迹法检测人基因工程干扰素中大肠杆菌残余成分

用大肠杆菌抽提物免疫家兔制备相应的抗血清,并用该血清建立免疫印迹法,检测基因工程干扰素中大肠杆菌残余成分。初步试验结果表明,该方法的灵敏度高于SDS-PAGE银染法。检测3批人α_1.型基因工程干扰素的结果表明,制品的纯度较好。     

A sandwich enzyme-linked immunosorbent assay for κ-carrageenan determination

High titre antisera to κ-carrageenan were produced by immunisation of rabbits and guinea pigs with K-carrageenan. These antisera, rabbit serum as a capture antibody and guinea pig serum as a detector antibody, were used in a sandwich enzyme-linked immunosorbent assay. The range of determination of K-carrageenan was from 16 to 256 ng ml^?1 in the assay. The antisera showed no cross-reactivity with six thickeners. The assay was developed for application to foods such as jelly and custard pudding and demonstrated many advantages including high sensitivity, technical simplicity and the minimal requirement for food sample preparation before assay.     

^51Cr释放法检测赖氨酸锗对NK细胞活性的作用

采用~(51)Cr释放法,以K_(562)瘤株为靶细胞,观察赖氨酸锗(Ge_(401))对正常人外周血NK细胞活性(NK-A)的作用。结果表明:Ge_(401)在50、100、200μg/ml三种浓度与效应细胞预处理18h后,NK-A(％)从对照组24.30分别提高为32.52(p<0.05),39.70(p<0.01),43.42(p<0.001),呈明显的剂量依赖性。同时,Ge_(401)在100、200μg/ml两种浓度时,对~(51)Cr标记的K_(562)靶细胞的~(51)Cr释放率无明显直接影响。提示Ge_(401)对K_(562)靶细胞无直接细胞毒作用,其促进NK-A的作用部位在于效应细胞。     

A method for the estimation of the culturing quality of dehydrated mycological media

A relatively simple technique called 'multiconidial inoculation method' was developed to evaluate the culturing quality of dehydrated culture media. Four commercial PDA media were compared for their ability to maintain both the vegetative and fruiting phase of growth of Aspergillus niger . The evaluation was carried out by metric and densitometric methods.     

Development of a rapid colorimetric method for the determination of chlorogenic acid in freeze-dried potato tubers

After-cooking blackening (ACB) in potato cultivars results from the formation of complex compounds of chlorogenic acid and iron ions. At present the estimation of chlorogenic acid content represents the most reliable method for predicting the extent of ACB in material in a potato breeding programme to allow subsequent selection. A number of methods for determining chlorogenic acid levels, including high performance liquid chromatography, sodium nitrite and other colorimetric and chromatographic assays, are evaluated. A rapid screening method for the direct determination of chlorogenic acid levels is described, and its application within a breeding programme and the results obtained from a number of cultivars are discussed.