The involvement of cytochromeP-450 monooxygenase system in aflatoxin biosynthesis byAspergillus flavus

Summary Phenobarbital stimulated aflatoxin biosynthesis byAspergillus flavus and this was paralleled by an increase in microsomal NADPH-cytochromeP-450 reductase and cytochromeP-450 activities. Aflatoxin biosynthesis was inhibited by SKF 525-A, metyrapone and cyanide, inhibitors of the cytochromeP-450 monooxygenase system, further suggesting that aflatoxin biosynthesis byA. flavus could be mediated by a cytochromeP-450 monooxygenase enzyme system.     

北京鸭脑钙调素的分离纯化和性质的研究

钙调素(Calmodulin,简称CaM)是一种多生理功能的调节蛋白,在脑的功能活动中有重要作用。本文采用苯基琼脂糖(phenyl-Sepharose CL 4B)层析和葡聚糖凝胶(Sephadex G-50)过滤法,从北京鸭脑中分离纯化出CaM。纯化的CaM经SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)和等电聚焦(IEF)电泳鉴定均为一条区带。分子量为19kD,等电点(pI)为4.15,消光系数为1.83。 对纯化的鸭脑CaM的活性和性质进行了研究。它可明显地激活牛环核苷酸磷酸二酯酶活性,在有Ca~(2+)存在的条件下,SDS-PAGE中出现电泳迁移速度的改变,紫外吸收光谱具有已知CaM特有的吸收多峰形,并观察了Ca~(2+)对荧光发射光谱的影响。其氨基酸组成中,1/3是酸性氨基酸,苯丙氨酸和酪氨酸的比例为8:2。与猪CaM和牛CaM的物理化学性质作了比较。     

Production of monoclonal antibodies against avian LHRH-I

Summary Production of antibodies against peptides or poorly antigenic proteins by conventional methods often requires either large quantities of the native immunogen or some chemical modification to increase their antigenicity. In this study an in vivo and in vitro immunization protocol has been used to generate monoclonal antibodies against the decapeptide luteinizing hormone-releasing hormone (LHRH). Two injections of 100 μg of avian LHRH-I into BALB/c mice were given 7 d apart. Dissociated splenocytes were collected under sterile conditions. They were incubated with 100 μg of the immunogen in 75-cm² tissue culture flasks in thymocyte-conditioned media. After 5 to 8 d exposure to the antigen, splenocytes were fused with SP2/O myeloma cells by polyethylene glycol. The cells were plated into 24 wells and then incubated in hypoxanthine aminopterin and thymidine selective media. After 14 d an initial screening was done by enzyme immunoassay. The positive wells (6/24) were expanded into 96-well plates and rescreened. Selected lines were cloned out 3 times by limiting dilution and the most positive expanded for ascites production. The antibody was affinity purified in a protein A column. The antibody cross-reacted with LHRH-I and II but preferentially to LHRH-I, as shown by competitive assay. A hypothalamic extract from a mature chick showed a higher response than preparations from whole brain explants of 1- to 3-d posthatched chicks, mature quail, and mature mouse. This work was funded by the Maryland Agricultural Experiment Station artical no. A4975, contribution no. 8019.     

云南10个民族红细胞酸性磷酸酶型分布调查

用淀粉凝胶电泳法对云南省汉族及9个少数民族的红细胞酸性磷酸酶(ACP_1)的表型分布进行了调查,检出A、BA和B3种表型,计算得云南汉、彝、白、傣、瑶、佤、哈尼、布朗、基诺和拉祜族ACP_1~A、ACP_1~B的基因频率依次为0.2067、0.7933;0.2406、0.7594;0.2341、0.7659;0.3750、0.6250;0.2300、0.7700;0.2727、0.7273;0.3594、0.6406;0.3036、0.6964;0.2381、0.76119和0.4474、0.5526。未发现ACP_1~C基因及其它稀有基因。研究表明,ACP_1表型的分布存在着一定的种族与民族差异。     

伊贝母体细胞无性系的建立及其胚状体的发生

本文报道了伊贝母体细胞无性系的建立及其胚状体的发生。已继代培养三年零六个月共30多代的鳞芽愈伤组织,目前仍有分化能力。通过愈伤组织形态细胞学的观察,发现伊贝母体细胞无性系形成小鳞茎的途径有二:一是由特化了的愈伤组织表皮细胞。经多次分裂发育成不定芽而形成小鳞茎;二是由愈伤组织表层或内层特化了的胚性细胞,经多次分裂发育成胚状体而形成小鳞茎。不定芽和胚状体的形态发生是有区别的。     

人γ干扰素突变体(rIFN-γ132-PGIL)的构建及其生物学活性的测定

利用DNA重组技术,去掉人γ干扰素(IFNγ)基因3′端含编码多肽羧基(C)端11个氨基酸的核苷酸序列,与编码P,G,I,L的DNA序列相连接,构成IFNγ突变体(rIFN-γ132-PGIL)基因,将后者插入pBV220P_RP_L串连启动子下游,转化大肠杆菌DH5α,在CIts857基因的调节下,通过升温诱导,获得了高效表达,表达量约占菌体可溶性蛋白的30％以上,抗病毒活性平均可达4.9×10~-8U/L,比母体菌株高10倍。SDS—PAGE结果表明,rIFN-γ132—PGIL分子量为17kd。     

糙叶败酱挥发油镇静作用的研究

本文观察了败酱科植物糙叶败酱(Patrinia scabra Bunge)根和根茎中制得的挥发油的镇静作用,井与黄花败酱挥发油做了比较。结果表明,此油灌胃给予数组小鼠,剂量0.45ml/kg,显示如下的作用:[1]能显著延长由于腹腔注射戊巴比妥钠(50mg/kg)引起的小鼠睡眠时间,但其作用强度弱于黄花败酱挥发油。(2)一次灌胃给予小鼠大剂量10.46g/kg的糙叶败酱挥发油,连续观察10天,动物外观正常,无一死亡,体重增加与对照组相似。