糠醛精制装置防腐蚀研究

针对糠醛精制装置的溶剂回收系统和湿醛系统腐蚀严重影响生产问题。进行了简要分析，研究、设计了化学工艺缓蚀的方案，经过生产实验和应用，效果明显，达到了预期效果。     

关于作者姓名和排名顺序的更正启事

<正>本刊发表在2012年第4期67—74页上的论文《α-N-乙酰半乳糖胺酶的表达及活性检测》(Overexpression and characterization of a bacterialα-N-acetylgalactosaminidase),其作者的中英文姓名和排名顺序应为     

Sterical hindrance promotes selectivity of the autophagy cargo receptor NDP52 for the danger receptor Galectin-8 in antibacterial autophagy

With the strong support from National Natural Science Foundation of China,the research team of Professor Shi Yunyu from the UniversiTy of Science and Technology of China,collaborated with Professor Felix Randow’s groups from the MRC Laboratory of UK,published their research findings in an article＂Sterical Hindrance Promotes Selectivity of the Autophagy Cargo Receptor NDP52 for the Danger Receptor Galectin-8 in Antibacterial Autophagy＂in Science Signal（2013,6（261）：ra9）.     

酿酒酵母可诱导启动子功能特性的研究

把大肥杆菌β－半乳糖苷酶基因克隆到带有ＧＡＬ１启动子的酶母诱导表达质粒ｐＹＥＳ２中，研究了酵母半乳糖诱导启动子ＧＡＬ１控制下的基因表达特性，研究表明，β－半乳糖苷酶基因的表达明显地受培养基中碳源的调节，产生的β－半乳糖苷酶可达细胞总蛋白含量的１０％左右，从而为利用可调控表达系统在酵母菌中实现外源基因较高水平表达打下了一定基础。     

Role of Notch expression in premature senescence of murine bone marrow stromal cells

The aim of the present study was to investigate the role of the Notch signaling pathway in premature senescence of murine bone marrow stromal cells in vitro. The intracellular domain of Notch 1 (ICN) was transfected into cultured murine bone marrow stromal cells by lipofectamine transfection. After three days, the proliferation of transfected cells was measured by MTT assay. Cell cycle distribution was analyzed by flow cytometry. Senescence-associated beta-galactosidase (SA-beta-gal) was measured, and the percentage of positive cells was evaluated by assessing 1000 cells in random fields of view. The expressions of p53 and p21Cip1/Waf1 were analyzed by both RT-PCR and Western blot analysis. The results showed that activation of Notch signaling inhibited proliferation of murine bone marrow stromal cells with induction of G1 arrest, increased the percentage of SA-beta-gal positive cells, and upregulated p53 and p21Cip1/Waf1 mRNA and protein expression levels. Thus, the activated Notch signaling could induce premature senescence of bone marrow stromal cells through the p53-p21Cip1/Waf1 pathway.     

腐牛乳中产β-半乳糖苷酶酵母菌菌株的分离和筛选以及该酶的提纯与固定化

从腐牛乳中分离筛选出一产β-半乳糖苷酶(E.C.3.2.1.23)酵母菌菌株(No.47).摇瓶发酵获酵母细胞,利用甲笨-自溶法破碎细胞,抽提的β-半乳糖苷酶通过2次丙酮沉淀,DEAE-纤维素(DE52)柱层析、羟基磷灰石柱层析进行纯化。该酶仅以一种分子形式存在。巯基与酶的活性中心有关。此酶对金属离子敏感,能被多种金属离子及SDS、Urea、EDTA等抑制。纯化的酶固定在戊二醛交联的明胶颗粒上,残活力为14%。固定化酶最适pH为6.6,而自然酶最适pH为6.4;固定化酶与自然酶最适温度均为45℃;固定化酶pH稳定范围为6.8-9.2,自然酶为6.4-9.2,自然酶为6.4—8.0;固定化酶热稳定性优于自然酶;以邻硝基苯酚-β-D-吡喃型半乳糖苷(简称ONPG)为底物,固定化酶表观米氏常数为3.4mmol·dm~(-3),自然酶米氏常数为2.5mmol·dm~(-3)。     

豇豆β—半乳糖苷酶性质研究

豇豆种子子叶提取液中存在高活性的β-半乳糖苷酶。经硫酸铵分级、DEAE-纤维素(DE-52)层析分离得到有β-半乳糖苷酶活性的四种酶,分别称之为β-半乳糖苷酶A、B、C和D。这四种酶分别经Sephadex G-150分子筛层析,用聚丙烯酰胺凝胶电泳分析纯度可达60％以上。这四种酶各自的最适PH、最适温度和热稳定性、分子量、Km及Ki,几种化学试剂对酶反应速度的影响均进行了讨论。     

葡聚糖凝胶过滤层析分离低聚半乳糖

采用葡聚糖凝胶Sephadex G-25柱对低聚半乳糖混合物进行了分离提纯,确定了适宜的洗脱流速和温度。结果表明,操作温度70℃,洗脱流速20mL/h,凝胶柱90cm×1cm,当进料量由1mL增至10mL,低聚半乳糖（GOS,三糖及三糖以上的低聚糖组分）的产量提高了4.62倍,整个洗脱过程只需4.1h,可以有效地去除葡萄糖,得到纯度为85.03%的含少量乳糖的GOS混合物。此混合物经过二次上柱后,分离效果明显优于一次上柱,得到的GOS质量分数达89.39%。