农药中色素合成抑制剂的研究和应用进展

光合作用在植物的生长过程中起着至关重要的作用,以光合色素生物合成过程中的酶作为靶标,是研发除草剂的一个重要方向和热点。其中原卟啉原氧化酶(PPO),八氢番茄红素去饱和酶(PDS),ζ-胡萝卜素去饱和酶(ZDS),对羟苯基丙酮酸双氧化酶(HPPD)等作为除草剂靶酶非常成功。本文综述了近年来农药中色素合成抑制剂的作用机制及最新应用进展,并展望未来的发展趋势。     

鹅细小病毒侵染雏鹅组织器官的氧化/脱氢酶及同工酶研究

酶是催化代谢途径的高效活性基因产物,应激环境和遗传基础的不同导致同工酶结构或活性差异,使不同组织和发育阶段的酶种类和活性表现特异性变化。采用生化分析试验技术和PAGE分析鹅细小病毒(GPV)感染雏鹅氧化/脱氢酶(LDH、ADH、POD、CAT)的活性及同工酶特征变异,结果表明,GPV感染雏鹅的脑、心脏、脾脏组织新出现1条POD同工酶谱带,肺脏组织消失1条同工酶谱带;GPV感染雏鹅的肝脏、脾脏组织分别缺失慢区3条和1条CAT同工酶谱带;GPV感染雏鹅组织器官的LDH和ADH同工酶仅显示1~2个慢区带,肺脏缺失1条慢区ADH同工酶谱带,ADH活性降低了13.61%~61.08%,心脏增高1.2倍;POD、CAT、LDH活性分别增强1.2~6、1.5~3.5、2~2.5倍,而脑、肺脏的CAT活性降低了40.29%和94.68%,心脏、肺脏的LDH活性降低了75.93%和91.81%。提示氧化/脱氢酶产生的广泛变异是GPV感染应激与宿主氧化/脱氢酶基因表达的互作效应,其酶的谱型、活性等生化特征变异,直接或间接调控代谢途径、影响生理机能及病理性能,敏感的氧化/脱氢酶是研究病毒基因型与宿主遗传易感性互作病理学机制的有效标记物。     

The manipulation and modification of tomato fruit ripening by expression of antisense RNA in transgenic plants

Summary The common cultivated tomato (Lycopersicon esculentum Mill.) provides a major focus for improvement of crop quality through genetic engineering. Identification of ripening-related cDNAs has enabled the modification of specific aspects of ripening by manipulating gene expression in transgenic plants. By utilizing antisense RNA to modify expression of ripening genes, we have inhibited the production of the cell wall-metabolising enzymes polygalacturonase and pectinesterase and created transgenic plants that contain, effectively, single, targeted mutations affecting these genes. Furthermore, this approach has been used with previously unidentified cDNA clones to enable both functional identification and manipulation of genes involved in ethylene production (ACC oxidase) and carotenoid biosynthesis (phytoene synthase). The use of antisense RNA targeted to specific genes to alter ripening phenotypes and improve commercial utility of fruit by affecting shelf-life, processing characteristics and nutritional content is discussed.We have used the extreme ripening-impaired mutant, ripening inhibitor (rin) to identify additional genes implicated in the ripening process. This approach has resulted in the cloning of several novel ripening-related mRNAs which are now being studied by antisense experiments. This may enable identification and manipulation of additional genes involved in processes such as softening, flavour and aroma generation and susceptibility to pathogens.Abbreviations ACC 1-aminocyclopropane-1-carboxylic acid - PE pectinesterase - PG polygalacturonase - SAM S-adenosyl methionine - SARs scaffold attachment regions     

Effect of deamination reaction mediated by semicarbazide-sensitive amine oxidase on 3T3-L1 adipocytes

AIM: To observe the effect of the metabolites generated from oxidative deamination of methylamine (MA) or benzylamine (BZA) catalyzed by semicarbazide-sensitive amine oxidase (SSAO) on 3T3-L1 adipocytes. METHODS: 3T3-L1 preadipocytes were induced to differentiation. SSAO activity was determined by high performance liquid chromatography (HPLC) at different differentiation time points. MTT assay was applied to detect cell vitality after exposure to different concentrations of MA or BZA. Fluorescence probe DCFH-DA was used to determine the production of reactive oxygen species after incubation of 3T3-L1 adipocytes with MA or BZA. After exposure to 0.5 mmol/L MA or BZA for 4 h, malondialdehyde (MDA), total superoxide dismutase (T-SOD) and glutathione (GSH) in the adipocytes or preadipocytes were measured. RESULTS: SSAO activity increased with the increase in the differentiation days, and reached a maximum at the 8th day. Incubation of the cells with different concentrations of MA or BZA for 4 h did not significantly decreased the cell vitality (P>0.05). After exposure to 0.5 mmol/L MA or BZA, the reactive oxygen species in adipocytes significantly increased, and were about 3 to 4 times as compared with control group (P<0.05). After treatment with 0.5 mmol/L MA or BZA for 4 h, MDA content significantly increased, while the activity of SOD and the expression of GSH decreased in mature adipocytes compared with control group (P<0.05). However, MDA, T-SOD and GSH did not change significantly after treatment with equal molar of MA or BZA in the preadipocytes (P>0.05). CONCLUSION: MA or BZA induces oxidative stress in the mature adipocytes, which might result from the deamination products catalyzed by SSAO.     

烟草感染PVYN后叶脉坏死与总酚、类黄酮及PPO关系研究

 本文采用常规摩擦接种和比色法研究了烟草感染PVY^N后叶脉坏死与总酚、类黄酮及PPO的关系。试验结果表明:感病品种K326接种PVY^N后总酚和类黄酮含量升高,且接种处理与未接种对照间总酚和类黄酮含量的差别随症状表现的加重有递增趋势;就部位而言,与根部及叶部相比,坏死严重的叶脉中总酚和类黄酮含量增加幅度最大,其含量分别增加了149.23%和152.97%;其PPO活性在接种PVY^N后3d时出现第一个高峰,比对照高213.61%,随后降至最低,但仍比对照高130.77%,在接种PVY^N后15d,坏死症状表现严重时,又迅速升高。抗病品种VAM接种PVY^N后无异常症状,其总酚和类黄酮含量也升高,但升高幅度不大,不同部位总酚及类黄酮含量增加的幅度也均小于25%,其PPO活性在接种PVY^N后稍有升高,但基本保持一个水平。     

葡萄糖氧化酶对蛋鸡日粮主要营养物质表观消化率及肠道微生物的调控作用

本研究旨在探讨葡萄糖氧化酶(glucose oxidase,GOD)对蛋鸡日粮营养物质表观消化率和肠道微生物的影响.采用单因子随机区组试验设计,将180只26周龄海兰褐蛋鸡随机分为5组,研究日粮中添加葡萄糖氧化酶对营养物质消化率以及盲肠微生物数量的影响.结果表明,日粮中添加0.1%、0.2%、0.3%和0.4%的葡萄糖氧化酶,试验组日粮粗蛋白质表观消化率分别提高15.25%(P<0.05)、28.40%(P<0.01)、23.32%(P<0.01)和26.10%(P<0.01);钙表观消化率分别提高3.37%(P>0.05)、4.71%(P>0.05)、8.01%(P<0.01)和7.30%(P<0.05);总磷的表观消化率分别提高17.74%(P>0.05)、16.30%(P>0.05)、24.58%(P<0.01)和27.32%(P<0.01).蛋鸡日粮中添加0.2%～0.4%葡萄糖氧化酶可显著提高盲肠内容物中乳酸杆菌数量,降低大肠杆菌数量.由此可知,葡萄糖氧化酶可调控肠道内微生态平衡,维护鸡的肠道健康,促进日粮营养物质的利用.     

鸡高尿酸血症模型的建立及别嘌呤对其的抑制作用

300只1日龄海兰褐蛋公雏,饲养至40日龄,通过在正常全价日粮中添加酵母和鱼粉建立高尿酸血症模型,并在全价日粮中添加别嘌呤,探讨其对高尿酸血症的抑制作用。结果表明,酵母高蛋白组和酵母高蛋白高钙组,鸡临床痛风症状明显,解剖发现心、肝、脾及肠系膜表面有石灰样的尿酸盐沉积,肾脏体积显著肿大,表面白色与红色相间,呈现典型的花斑肾病变。血中尿酸含量和黄嘌呤氧化酶（XOD）活性显著升高（P〈0.01）。别嘌呤可显著降低血中尿酸含量和XOD活性（P〈0.01）;说明高蛋白和高钙可诱发鸡高尿酸血症,别嘌呤对其有抑制作用。     

松嫩平原西部盐碱草地土壤多酚氧化酶活性及其与主要肥力因子的关系

对松嫩平原西部盐碱草地土壤多酚氧化酶活性及其与主要肥力因子的关系进行研究,结果表明,在植被生长季各月份内,多酚氧化酶活性在不同地段的变化有一定的规律性,都表现为碱斑裸地及植被生长较差的地段酶活性较高,而植被生长茂盛的地段酶活性低,但不同地段多酚氧化酶活性的季节变化规律不同;除钾素外,多酚氧化酶活性和肥力因子间都有显著或极显著的相关关系,全盐对酶活性的直接效应最大,且通过全氮、速效磷、有机质、pH值的间接效应也较大,是影响酶活性的重要因素;主成分分析表明,可以用多酚氧化酶活性来指示土壤全盐、pH值、全氮、速效磷和有机质的变化。     

葡萄糖氧化酶的微生物发酵生产工艺研究

葡萄糖氧化酶作为一种重要的氧化还原酶,在饲料、畜牧等行业应用广泛,可用于改善动物饲料的消化利用率.本文对葡萄糖氧化酶的发酵生产工艺、提取纯化工艺、酶学特性改进工艺及质量控制工艺作了简单介绍,以期为葡萄糖氧化酶的工业化生产和应用提供帮助.     

Research on Oxalate Oxidase and Its Genes in Plants

This paper introduces the discovery,composition and structure of oxalate oxidase,as well as illustrates the biological functions of this enzyme.With a comprehensive introduction upon previous researches upon gene cloning and heredity transformation of this enzyme,it indicates that heredity transformation can increase the content of oxalate oxidase within the plants and also enhance their resistance.The paper also points out the problems such as lack of gene resources and difficulty in the transformation of heterologous genes,and the focus in later researches should be laid upon the exploration of plant resources relative to this enzyme and selection of resistant species.