Effects of feed composition,protein denaturation and storage of milk serum protein/lactose powders on lactosylation

During whey powder production, the feed is subjected to several heat treatments which can cause lactosylation of proteins. In this study, lactosylation of whey proteins was evaluated in spray-dried powders before and after storage by varying the native protein fraction as well as the serum protein/lactose ratio in the powders. The lactosylation of native α-lactalbumin and β-lactoglobulin in the powders before storage was not affected to a large extent by the protein denaturation or if the feed had been heat treated in a high or low lactose environment. After storage (relative humidity of 23.5%, 30 °C, 25 days), the kinetic of lactosylation tended to increase with increasing native protein fraction and bulk protein content in the powders. An explanation could be that proteins dissolved in the lactose glassy structure might have a lower reactivity, while proteins present in the protein glassy structure with dissolved lactose may display higher lactosylation reactivity.     

罐装降脂减肥果茶生产工艺的研究

本文介绍了以各种中药材为主要原料 ,配以茶叶为辅料 ,运用先进的处理方法制备降脂减肥果茶的生产工艺、质量标准 ,并对确定生产工艺的几个主要问题进行了探讨     

叶绿素衍生物─CPD_4在人血清中的激发和发射荧光谱

叶绿素衍生物４号（ＣＰＤ４）是一种新型中药光敏剂，本文研究了不同浓度的ＣＰＤ４分别在含１０％不同血型人血清的生理盐水中以及纯生理盐水中的激发和发射荧光光谱，并对结果进行了分析，结论对ＣＰＤ４在光动力诊断恶性肿瘤的临床应用具有一定的指导意义．     

Evaluation of Serum Volume Losses During Long-Term Storage

Aliquots of serum collected in a large case-control study of cervical cancer were stored at −70°C for up to 4 years during implementation of the study. When 500 μL serum aliquots were thawed in preparation for carotenoid and vitamin A assays, volumes were noticeably variable and fell below 500 μL in the majority of the samples. We were concerned about evaporation/sublimation during storage of the samples because loss of water would concentrate the analytes of interest. We evaluated the use of density and sodium ion concentration measurements to confirm its occurrence. We found that serum density was an unreliable indicator of extent of volume loss since the anticipated increases in density due to evaporation were of the same magnitude as inter-individual variation in serum density. In contrast, Na⁺ concentration is tightly regulated and would rise if water had been lost from the samples. In a representative sample of serum aliquots from the case-control study, 24 of 25 vials contained less than 500 μL of serum. The mean sodium ion concentration (138.1 ± 3.6 mmol/L) was within the normal range for human serum of 136–145 mmol/L, and no correlation was observed between serum volume and Na⁺ concentration. These results strongly suggest that the observed low volumes were not due to evaporative losses. Instead, the variably low volumes of serum aliquots were probably due to pipetting errors in the initial aliquotting resulting from the use of air-displacement pipettes.     

甘薯糖蛋白SPG-1的分离纯化及其降血糖作用研究

经水溶提取、乙醇沉淀、离子交换层析、凝胶过滤层析等步骤，从广薯98中分离到甘薯糖蛋白组分SPG-1，经SDS一聚丙烯酰胺凝胶电泳和凝胶过滤层析鉴定，为单一组分甘薯糖蛋白纯品。SPG-的糖含量为98．4％，蛋白舍量为1．6％，等电点为5．03。通过灌胃给药，研究了SPG-1对正常小鼠和四氧嘧啶诱导的糖尿病小鼠血糖的影响，结果表明SPG-1对正常小鼠的血糖没有明显影响（p〉0．05），对四氧嘧啶诱导的糖尿病小鼠具有明显（p〈0．01）的降血糖功能。     

伤寒沙门氏菌特异性θ诊断血清的应用

应用新的特异性θ诊断血清和传统商品血清与434株伤寒沙门氏菌地方株作玻片凝集平行试验，两者诊断符合率为100％。θ血清与0．1％酚琼脂斜面上的所有伤寒沙门氏菌呈迅速清晰的阳性凝集反应。鉴于θ血清与大多数D群沙门氏菌不凝集，因此，大大提高诊断的正确性。     

妊娠相关血浆蛋白A的分离及纯化

采用人胎盘血为原料,利用Sephadex G-200,DEAE-Sephadex A-50层析,Sepharose 4B反相免疫亲和层析技术,获得妊娠相关血浆蛋白A(PAPP-A)纯品,经8.0％聚丙烯酰胺凝胶电泳、免疫电泳、双向免疫扩散证明,所提取的PAPP-A纯品为单一成分。免疫家兔获得抗血清,其效价在1:16以上。     

蛋白质在超滤过程中的膜污染和膜清洗

本文选用四种不同的膜清洗剂对牛血清蛋白溶液超滤后污染的三种超滤膜进行研究，结果表明：在蛋白质的等电点取得在不同ＰＨ值下蛋白质对膜污染的最佳清洗效果，清洗效率与蛋白质的所荷电荷有关。采用适宜的清洗过程将会延长膜使用寿命和增强超滤膜性能。     

表面带磺酸基团的聚苯乙烯微球的制备及其对蛋白质的吸附

研究了运用分散聚合法,在乙醇/水混合介质中,制备2-丙烯酰胺基-2-甲基丙磺酸(AMPS)与苯乙烯(St)的共聚微球。运用红外、核磁共振、激光光散射和扫描电子显微镜对功能微球进行表征。阐述了该微球对牛血清蛋白(BSA)的吸附量与吸附时间和pH值的关系。结果表明:功能微球对BSA的吸附先随时间的增长而增大,一段时间后达到平衡吸附。当pH值接近BSA等电点(pI=4.7)时,BSA的吸附量达到最大值。