Effects of baicalin on CA46 cell xenografts in nude mice

AIM: To study the effects of baicalin on CA46 cell xenografts in nude mice. METHODS: The nude mice with CA46 cell xenografts were treated with drugs via intraperitoneal injection daily, and were divided into 5 groups: negative control group, 15 mg/kg baicalin group, 30 mg/kg baicalin group, 60 mg/kg baicalin group and 4 mg/kg etoposide (VP-16) positive control group. After 12-day treatment, the weight of CA46 cell xenografts stripped from some nude mice in the 5 groups was used to evaluate the effect of baicalin on xenograft growth in the nude mice. The apoptosis, necrosis and pathological changes of the xenograft cells were examined under light microscope and transmission electronic microscope respectively. The expression levels of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway-related proteins extracted from xenografts were determined by Western blotting. The other nude mice with CA46 cell xenografts in the 5 groups continued to be treated with the drugs until death in order to evaluate the effect of balcalin on survival time of the nude mice with CA46 cell xenografts. RESULTS: Baicalin remarkably inhibited the growth of CA46 cell xenografts, induced apoptosis and necrosis of xenograft cells, and reduced the protein expression of phospho-Akt (p-Akt), nuclear factor-kappa B (NF-κB), mammalian target of rapamycin (mTOR) and phospho-mTOR (p-mTOR) in the xenografts after 12-day treatment. Furthermore, baicalin prolonged the survival time of the nude mice with CA46 cell xenografts in a dose-dependent manner. CONCLUSION: Baicalin inhibits the growth and induces apoptosis of CA46 cell xenografts in the nude mice, and prolongs the survival time of the nude mice with CA46 cell xenografts through the mechanism of down-regulating PI3K/Akt/NF-κB and PI3K/Akt/ mTOR signaling pathways.     

四川冕宁县缺硒饲粮对雏鸡的影响及不同品种雏鸡适宜补硒量的研究

采用四川严重缺只硒地区冕宁县实用雏鸡饲粮饲喂泸宁鸡(当地地方鸡)、白洛克和来杭三个品种共682只雏鸡,作了两个试验,结果表明:谷实类缺硒饲粮(含硒0.0051ppm)引起雏鸡严重营养性胰腺萎缩和纤维化;泸宁鸡和白洛克缺硒死亡率分别为83％和63％,添加维生素E可起到轻微缓解作用(缺硒死亡率52％);补硒显著促进生长和改善饲料利用率。饲粮中添加动物性饲料(使基础日粮含硒0.1018ppm)后雏鸡未出现明显缺硒病变,但补硒显著提高谷胱甘肽过氧化物酶(GSH-px活力、组织硒含量和生长速度。雏鸡对缺硒的敏感程度、组织硒含量和GSH-px活力存在明显品种差异。以GSH-px活力和组织硒含量作为评定标准结合对生长速度的考察表明:对于生长较快的泸宁鸡和白洛克,基础饲粮补加0.20ppm硒是适宜的,而对于蛋用型来杭鸡则以添加0.10ppm效果较好。     

中林-46杨他感作用初探

为了提高中彬－４６杨混农速生丰产林的生产能力,用中林－４６杨根系浸提液处理主要农作物和常见田间杂草种子进行发芽试验,结果表明：中林－４６杨的他感作用是存在的,其根浸的液对大豆种子的萌发没有影响,但对其幼苗的生长有极显著的促进作用;低浓度的浸提液对花生生长的影响不明显,高浓度时则有极显著的促进作用;     

人CD46基因启动子的克隆和启动特性研究

为研究人CD46(hCD46)基因启动子的启动特性,研制具有hCD46组织特异性表达特征的转基因小鼠,设计扩增hCD46基因启动子的PCR引物,用HeLa细胞基因组DNA为模板扩增hCD46基因启动子DNA片段,测序结果表明:其序列与GenBank中hCD46完整基因5′端某片段的同源性高达99.9%。用此DNA片段替换表达载体pcD-NA3EGFP中的CMV启动子,且在该片段与EGFP基因之间插入兔β-球蛋白基因的第2内含子RGI。重构的表达载体在2种鼠源细胞CHO和SP2/0中均可启动EGFP表达,表达量与人体内同源组织中hCD46的相似,说明该研究克隆了结构和功能正确的hCD46基因启动子。     

三种速生杨木材物理力学性质的比较研究

测试、分析比较了不同树龄3种速生杨木材的物理力学性质,结果表明:①树种对物理力学性能有较大的影响,三倍体圆叶毛白杨的物理力学性能最好,三倍体裂叶毛白杨次之,中林-46最差;方差分析表明,3种杨树的主要物理力学性质均达到显著和极显著差异。②树龄对物理力学性质的影响不大,随着树龄的增长,不同杨树木材的密度已趋于稳定,但力学性能有上升的趋势;方差分析表明,抗截切强度和抗弯强度受树龄影响较大,差异达到显著水平,其他性质无显著差异。     

锥—46抑制[^3H]次黄嘌呤掺入伊氏锥虫核酸的研究

用液体闪烁计数法对锥—46的抗锥虫作用的机理做了初步研究。发现T-46与Berenil很相似,均可显著抑制[~3H]次黄嘌呤掺入伊氏锥虫,抑制作用与浓度及时间呈正相关。T-46和Berenil对DNA合成的IC_(60)分别为1.33和1.73μg·ml~(-1)。本实验还提示T-46抗锥虫作用可能与损伤DNA模板有关。     

Investigations on the Occurrence of Hereditary Diseases in the Danish Cattle Population 1989-1991

Agerholm, J.S., A. Basse and K. Christensen: Investigations on the occurrence of hereditary diseases in the Danish cattle population 1989-1991. Acta vet. scand. 1993, 34, 245-253.– The methods of the Danish Bovine Genetic Disease Programme are outlined, and the results obtained during the first 3 years in function are described. The most common disease reported was spinal muscular atrophy in calves of the Red Danish Dairy breed with 312 reports. Necropsy was performed on 162 cases, and spinal muscular atrophy was diagnosed in 82 of these. Bovine progressive degenerative mye-loencephalopathy, rectovaginal constriction, syndrome of arthrogryposis and palatoschisis, hereditary chondrodysplasia (2 different types), syndactylism, epitheliogenesis imperfecta, and osteogenesis imperfecta was diagnosed with 1 case each. Lethal trait A46 was diagnosed in 4 calves. Some of these diseases have not previously been described in Denmark, and epitheliogenesis imperfecta was for the first time diagnosed in the Hereford breed. Chromosome translocation 1/29 was detected in the Blonde d’Aquitaine (BAQ), Limousine, and Red Danish Dairy breed. The aberration occurred frequently in BAQ. Furthermore, a complex chromosome translocation t(l;8;9)(q45;ql3;q26) was detected in the Red Danish Dairy breed.     

Synthetic tetramer of a Phytophthora sojae-inducible fragment from soybean GmaSKTI36 promoter improves its pathogen induction activities

Using pathogen-induced promoters to control expression of the functional genes in transgenic plants may greatly increase the chances of boosting disease resistance. However, the number of the inducible promoters is limited. Here, we found that soybean GmaSKTI36 gene is strongly induced upon Phytophthora sojae infection. Functional analysis showed that its promoter could mediate rapid and strong induction of GUS expression upon pathogen infection in both Nicotiana benthamiana leaves and soybean hairy roots. Then, a 122 bp fragment that was critical to the activity was successfully identified by a progressive 5′ deletion analysis. Importantly, we found that a synthetic promoter by tetramerizing this fragment could confer strong P. sojae induction activities. Overall, the results suggested that the GmaSKTI36 promoter, the 122 bp fragment, and the synthetic promoter are potentially useful pathogen-inducible promoters.     

RNA干扰技术抑制新家坡石斑鱼虹彩病毒感染细胞多肽ICP46与绿色荧光蛋白融合基因的表达

新加坡石斑鱼虹彩病毒（singapore grouper iridovirus,SGIV）是一种严重的能引起全身性疾病的病原体,对石斑鱼养殖造成了重大的经济损失。将含有SGIV感染细胞多肽ICP46（infected cell polypeptides 46）基因的真核表达载体pEGFP-ICP46转染到胖头鲤细胞（fathead minnow cells,FHM）中进行融合表达,用荧光显微镜观察到ICP46-GFP融合蛋白主要分布于FHM细胞的细胞质中。根据SGIV-ICP46的序列,设计并体外化学合成了特异性干扰SGIV-ICP46的siRNA（siRNA-ICP46）,与pEGFP-ICP46共转染到FHM细胞中,通过荧光显微镜观察不同时间点荧光强度的变化。转染后24~48 h,实验细胞（共转染siRNA-ICP46和pEGFP-ICP46）和阳性对照细胞（共转染siRNA-GFP和pEGFP-ICP46）中的荧光微弱,发荧光的细胞数量较阴性对照（共转染siRNA-Negative和pEGFP-ICP46）少70%左右,但其后实验细胞和阳性对照细胞的荧光强度开始增强,在转染后72 h其与阴性对照组已差别不大。说明体外化学合成的siRNA-ICP46转染后24~48 h可有效抑制FHM细胞中外源导入SGIV-ICP46基因的表达。     

猪肺炎支原体膜蛋白P46基因在大肠杆菌中的表达

把猪肺炎支原体(Mycoplasma hyopneumoniae)国际标准株232的P46基因克隆进pGEM-T-EASY载体上,通过PCR方法把该基因中三个编码Trp的密码子TGA突变为TGG,然后将该基因亚克隆到载体pMAL-P2X上,得到重组表达载体pMAL-P2X-P46.用该重组载体转化大肠杆菌TB1,得到表达重组菌TB1-pMAL-P2XA-P46,用终浓度为0.3 mM的IPTG在37℃下诱导表达,获得可溶性表达的融合蛋白MBP-P46,在免疫印迹试验中,兔抗MBP高免血清和兔抗猪肺炎支原体高免血清都能与目的蛋白发生阳性反应,证明猪肺炎支原体P46基因在大肠杆菌里获得了可溶性表达.该融合蛋白对于建立特异性和敏感性好的EIISSA方法具有重要意义.