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31.
苦皮藤素类似物的合成与结构鉴定   总被引:7,自引:2,他引:7       下载免费PDF全文
以苦皮藤Celastrus angulatus Max.提取物水解产物中的多羟基β-二氢沉香呋喃为原料,合成了对粘虫Mythimna separata具有毒杀活性的苦皮藤素(Celangulin)类似物,并在活性追踪的指导下分离得到了两个具有杀虫活性的苦皮藤素类似物 A和B, 其结构经核磁共振谱、快原子轰击质谱、高分辨质谱等波谱学方法鉴定为2β,6α,8β,13-四异丁酰氧基-1β,4α,9α-三羟基-β-二氢沉香呋喃及1β,2β,6α,8β,13-五异丁酰氧基-4α,9α-二羟基-β-二氢沉香呋喃。化合物 A和B 均为新化合物,在20 mg/mL的浓度下对三龄粘虫Mythimna separata的胃毒活性(死亡率)分别为89.5%和93.2%。  相似文献   
32.
AIM: To study the expression of vascular endothelial growth factor (VEGF) in inflammatory mucosa of lacrimal sac. METHODS: Immunohistochemical S-P method was used to examine the expression of VEGF in the mocusa from 12 patients with chronic dacryocystitis and 8 volunteers. RESULTS: The positive rates of VEGF expression in different parts of the mocusa were: basal lamina: 44.3%±7.6%; surface epithelium: 16.9%±4.6%; connective tissue: 15.2%±4.9%, all normal mocusa of 8 cases were negative. There was a significant difference between the two groups (P<0.01), a significant difference among each part of the chronic inflammatory mocusa of lacrimal sac. CONCLUSION: VEGF may play an important role in hyperplasia of inflammatory mucosa of lacrimal sac.  相似文献   
33.
AIM: To investigate the effect of sodium nitroprusside (SNP) on activation of nuclear factor κB. METHODS: The techniques of culture of human T lymphocytes, Western blot and RT-PCR were applied. The effects of NO donor sodium nitroprusside (SNP) at different concentrations on mRNA and protein expression of IκBα in human T lymphocytes at 30 min or 120 min after stimulating with phytohaemagglutinin (PHA-P) were observed. RESULTS: SNP at middle or high concentrations reduced the degradation of κIBαprotein 30 min after stimulating with PHA-P,and increased the re-expression of κIBαmRNA 120 min after stimulating with PHA-P significantly.CONCLUSION: The mechanism of inhibitory effect of SNP at middle or high concentrations may be due to the decrease in degradation and the increase in re-synthesis of κIBα.The regulatory mechanism of SNP at low concentration may not be through κIBα.  相似文献   
34.
AIM: To investigate whether protein kinase C (PKC) is involved in the proliferation and the telomerase expression in human hepatocellular carcinoma cells. METHODS: Human hepatocellular carcinoma cells (BEL-7402) were treated with exogenous phorbol-12-myristate-13-acetate (PMA, PKC activator) and staurosporine (SP, PKC inhibitor) for 48 hours. The techniques of cell culture and the telomeric repeat amplification protocol silver staining in combination with computer image scanning system in vitro were used to observe the variations of the growth and the telomerase expression. RESULTS: The proliferative potential of BEL-7402 cells was decreased by the action of PMA as well as SP, and the telomerase expression was also inhibited by PMA and SP. CONCLUSION: Our findings suggest that the proliferation of human hepatocellular carcinoma cells and the telomerase expression may be related to PKC.  相似文献   
35.
AIM: To investigate the effects of angiotensin-converting enzyme inhibitors (ACEI), fosinopril, captopril and angiotensin II AT1 antagonists, valsartan on tissue factor (TF) expression on monocytes induced by lipopolysaccharide (LPS). METHODS: Mononuclear leukocytes from normal delivered female umbilical veins were incubated with bacterial LPS in presence or absence of different ACE inhibitors .At the end of incubation, the cells were disrupted by 3 freeze-thaw cycles. TF procoagulant activity was assessed by a one-stage clotting assay. RT-PCR was used to check TF mRNA expression, and GAPDH mRNA was used for parallel assay. RESULTS and CONCLUSION: The results showed that increased expression of TF mRNA induced by LPS was inhibited by fosinopril, captopril and valsartan, respectively, and the procoagualant activity of monocytes was also reduced.  相似文献   
36.
LIU Ping-ping  ZHANG Yuan 《园艺学报》2004,20(11):2053-2057
AIM: To investigate the effects of β-mercaptoethanol (β-ME) and all-trans rentinal acid (RA) on glial fibrillary acidic protein (GFAP) expression in mesenchymal cells derived from mouse fetal liver in vitro. METHODS: Cells suspension from 14.5-days-old mouse fetal liver were cultured in DMEM/HEPES/F12 supplemented with 20% FCS and mesenchymal cells were acquired after discarding nonadherent cells. The 5th passage cells were induced by β-ME and RA. The characteristics of treated cells were assayed by immunocytochemistry staining at 5 hours and 5 days after induction. β-actin as an internal control, GFAP gene expression of mesenchyal cells was detected with semi-quantitative RT-PCR. RESULTS: After being inducted by β-ME and RA, 80% approximately of the cells exhibited typical neural morphology and about 85% expressed GFAP phenotype. Semi-quantitative RT-PCR showed that mRNA expression of GFAP increased in treated cells versus untreated cells (P<0.01). CONCLUSION: GFAP expression in mesenchymal cells derived from mouse fetal liver in vitro increases after being treated with β-ME and RA.  相似文献   
37.
鸭疫里氏杆菌形态特征的电镜观察   总被引:8,自引:0,他引:8  
自鸭传染性浆膜炎的病死鸭中分离鉴定的鸭疫里氏杆菌(RA)Ⅰ、Ⅱ型两个菌株,用负染法和超薄切片法制备样品,于透射电镜下进行观察。结果观察到约占1/3的RA具有特殊的形态结构:在细菌的顶端或侧面有1~2个与菌体相连的芽状赘生物,有的也能从菌体上脱落下来。它在超薄切片中的大小约为菌体的1/3~1/5,能观察到其内部也具有类似菌体内部的结构。且具有类似菌体的“细胞壁”,类似于核体部分的结构位于“细胞壁”的一侧。而用相同的方法制作的鸭大肠杆菌(E.cozi)对照样品,却见不到这种特殊的形态结构。说明这种形态特征可能是RA特有的。  相似文献   
38.
对从国外和北京引进的13个牧草品种在金衢盆地进行了栽培及品比试验。结果表明:籽粒苋、苏丹草、俄罗斯饲料菜、甜高梁等鲜草产量高;紫花苜蓿、白三叶、鲁梅克斯、欧洲菊苣、籽粒苋等牧草粗蛋白含量较高,在20%以上;冬牧70黑麦草出苗后可在严寒的冬季生长,且产量高;特早熟二倍体和意大利四倍体黑麦草生育期长,可延长黑麦草利用期1个月左右。  相似文献   
39.
Sperm concentration of wild yak bull is 2. 13 billion per milliliter. Survival time at 0-4 ℃ is 57hrs. After thawing survival time at 37 ℃ is 12 hrs. Resistance coefficient is 144,000. Abnormal sperm rate and acrosomal integrated rate of post-thawing is 9.17% and 87.53% respectively. Moving viscosity is 1. 169 cp. Total nitrogen is 1 437.7 mg/100 ml. Head of sperm is significantly shorter and end piece is significantly longer than that of domestic yak and yellow cattle. Activity of hyaluronidase is highly stronger than the domestic yak,and the activity of LDH is higher than the domestic yak by 48 %. Hence,the fertility of the wild yak bull is powerful and the artificial inseminated rate with domestic yak and yellow cattle is 88.9% and 71.58% respectively.  相似文献   
40.
张尧  李忠晴  王爱英  祝建波 《草业学报》2018,27(12):199-207
天山雪莲生长于常年积雪覆盖高海拔处的高山区域,具有很强的极端低温生境适应能力,属于研究植物低温适应的良好模式植物。前期的研究表明,sikFBA4基因可以显著提高番茄的抗寒能力。为进一步研究sikFBA4基因的耐寒响应模式,以天山雪莲为材料,采用实时荧光定量PCR分析sikFBA4在低温胁迫下的表达模式;利用高效热不对称PCR法(Hi-Tail PCR)克隆sikFBA4启动子序列并进行生物信息学分析。为分析PsikFBA4序列克隆的完整性及转录表达特性,将PsikFBA4与GUS基因融合在烟草中进行瞬时表达。结果表明,sikFBA4在低温胁迫条件下的表达发生瞬时显著上调,并在1 h达到峰值,而后表达下调。通过启动子克隆分析,在PsikFBA4序列-1648 bp位置处具有冷响应元件LTRE;进一步的GUS染色和酶活力测定结果表明,低温能够显著提高GUS基因的表达活性,说明sikFBA4属于低温诱导型基因。SikFBA4基因启动子的克隆、序列分析以及表达分析,为进一步探究雪莲果糖-1,6-二磷酸醛缩酶(sikFBAs)基因的表达与调控机制奠定了基础。  相似文献   
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