Elevated auxin and reduced cytokinin contents in rootstocks improve their performance and grafting success

Plant grafting is an important technique for horticultural and silvicultural production. However, many rootstock plants suffer from undesirable lateral bud outgrowth, low grafting success rates or poor rooting. Here, we used a root‐predominant gene promoter (SbUGT) to drive the expression of a tryptophan‐2‐monooxygenase gene (iaaM) from Agrobacterium tumefaciens to increase auxin levels in tobacco. The transgenic plants, when used as a rootstock, displayed inhibited lateral bud outgrowth, enhanced grafting success rate and improved root initiation. However, root elongation and biomass of SbUGT::iaaM transgenic plants were reduced compared to those of wild‐type plants. In contrast, when we used this same promoter to drive CKX (a cytokinin degradation gene) expression, the transgenic tobacco plants displayed enhanced root elongation and biomass. We then made crosses between the SbUGT::CKX and SbUGT::iaaM transgenic plants. We observed that overexpression of the CKX gene neutralized the negative effects of auxin overproduction on root elongation. Also, the simultaneous expression of both the iaaM and CKX genes in rootstock did not disrupt normal growth and developmental patterns in wild‐type scions. Our results demonstrate that expression of both the iaaM and CKX genes predominantly in roots of rootstock inhibits lateral bud release from rootstock, improves grafting success rates and enhances root initiation and biomass.     

阳性脂质体介导反义寡聚核苷酸转染HeLa细胞的效果研究

采用FITC标记的未经修饰的和经过修饰的两种19-mer反义寡聚核苷酸序列(ODN19和S-ODN19)作为转染物质,用流式细胞技术(FCM)研究比较几种常用阳性脂质体介导的寡聚核苷酸转染HeLa细胞的效果及适宜的转染时间。未经化学修饰的ODN19转染结果显示,LipofectAmine和DM-RIE-C增强转染的作用相对较强,而其他两种脂质体的作用并不明显。对于经过修饰的S-ODN19转染而言,四种阳性脂质体均具有增强S-ODN19转染作用,但以LipofectAmine的效果最为明显,其转染效果(FITC均值为5203.11)为无脂质体介导对照的数十倍。四种阳性脂质体的增强转染作用排序为:LipofectAmine>FuGENE6>Lipofectin>DM-RIR-C。另外,在用FuGENE6介导寡聚核苷酸转染时,采用4小时转染时间可获较好转染效果。     

牛筋条的新化合物

从牛筋条（Dichotomanthes tristaniaecarpa)地上部分分离得到8个化合物,经^1HNMR,^13CNMR,MS等波谱分析,它们被分别鉴定为羽扇豆醇（1）,白桦脂醇（2）,5,7-二羟基色酮（3）,（-）-表儿茶素（4）,圣草酚3′-O-β-D-葡萄糖苷（5）,圣草酚7-O-β-D-（6′-乙酯基）-吡喃葡萄糖醛酸苷（6）,圣草酚7-O-β-D-（6′-甲酯基）-吡喃葡萄糖醛酸苷（7）,野蔷薇苷（8）,其中化合物6,7为新化合物。     

Targeted Exosomes for Drug Delivery: Biomanufacturing,Surface Tagging,and Validation

Exosomes hold great potential to deliver therapeutic reagents for cancer treatment due to its inherent low antigenicity. However, several technical barriers, such as low productivity and ineffective cancer targeting, need to be overcome before wide clinical applications. The present study aims at creating a new biomanufacturing platform of cancer‐targeted exosomes for drug delivery. Specifically, a scalable, robust, high‐yield, cell line based exosome production process is created in a stirred‐tank bioreactor, and an efficient surface tagging technique is developed to generate monoclonal antibody (mAb)‐exosomes. The in vitro characterization using transmission electron microscopy, NanoSight, and western blotting confirm the high quality of exosomes. Flow cytometry and confocal laser scanning microscopy demonstrate that mAb‐exosomes have strong surface binding to cancer cells. Furthermore, to validate the targeted drug delivery efficiency, romidepsin, a histone deacetylase inhibitor, is loaded into mAb‐exosomes. The in vitro anti‐cancer toxicity study shows high cytotoxicity of mAb‐exosome‐romidepsin to cancer cells. Finally, the in vivo study using tumor xenograft animal model validates the cancer targeting specificity, anti‐cancer efficacy, and drug delivery capability of the targeted exosomes. In summary, new techniques enabling targeted exosomes for drug delivery are developed to support large‐scale animal studies and to facilitate the translation from research to clinics.     

黄海鳀鱼时空分布季节差异分析

利用1986-2010年的底拖网调查数据,基于GIS的空间分析和地统计分析技术,从不同角度阐明在捕捞压力和气侯变化的双重胁迫下,黄海鳀鱼资源密度时空分布及其变动的季节差异.结果表明:不同季节鳀鱼空间分布趋势变化明显,冬季,资源密度从调查区域东北部向岸边和南部水域递减,春季,与冬季相反,资源密度由岸边向东部水域递减,夏季,整体上资源密度呈北高南低的趋势,但高值点散乱分布,秋季,与冬季相似,资源密度由东部水域向岸边环形递减,但变化梯度较冬季缓和;鳀鱼资源密度重心季节变化明显,但不同年代变化规律并不相同;1986-2010年,春、夏和秋3个季节,鳀鱼资源密度重心均向北移动,冬季,资源密度重心年间变化明显,但无整体迁移规律;不同季节,鳀鱼资源密度高值聚集区空间分布位置不同.     

禽流感抗原基因NA,HA的克隆及其表达载体的构建

HA和NA是禽流感病毒重要的保护性抗原基因,为了得到禽流感植物疫苗,本试验采用高保真PCR扩增方法得到目的基因,分别克隆到pMD18-T载体.经测序证实核酸序列正确后,克隆到含有GUS基因的高效植物双元表达载体pB1121上,获得含有HA/NA基因的植物双元表达载体pB1121-HA和pB1121-NA,采用冻融法将含HA/NA基因的植物双元表达载体转入根癌农杆菌LBA4404,菌液浸染生菜子叶,共培48小时后进行GUS基因表达检测,x-glue染色显蓝色,说明带有HA/NA的植物双元表达载体构建成功,为下一步的生菜转HA/NA基因研究奠定基础.     

Enzyme immobilization for biodiesel production

Biodiesel has attracted more and more attention in recent years because of its biodegradability, environmentally friendliness, and renewability. Contrary to the conventional chemical catalysis method to produce biodiesel, the biochemical catalysis method developed quickly in the past decade and many immobilized enzymes are commercially available to meet the large-scale industrialization of biodiesel. This review is focusing on the current status of biodiesel production by biochemical catalysis method, especially the commercial enzyme and its immobilization for biodiesel production. Consequently, we believe that biochemical catalysis with immobilized enzymes is bound to be an alternative method instead of chemical catalysis in biodiesel production in the near future.     

细胞膜相联钙结合蛋白的结构和功能研究进展

细胞膜相联钙结合蛋白(PCaP)是定位于细胞膜上的一类新的Ca2+结合蛋白。简要综述了PCaP的蛋白结构、调控Ca2+/磷脂酰肌醇3-磷酸信号通路的分子机制、调节微管微丝稳定的能力,以及其在植物顶端生长极性中的功能研究进展。     

水稻病程相关PR1家族蛋白质在叶片生长及与白叶枯病菌互作反应中的表达

病程相关(PR)蛋白质经常被用作抗病反应的分子标记。利用免疫印迹(WB)技术检测了7个PR1家族蛋白质在水稻(Oryza sativa)叶片生长及与白叶枯病菌互作反应过程中的表达,发现6个PR1家族蛋白质在叶片生长中有表达。检测PR1蛋白质在Xa21介导的抗白叶枯病过程中的表达,结果显示PR1#052、PR1#072、PR1#073和PR1#121四个蛋白质在抗病反应后期呈上调或诱导表达,PR1#071则表达下调。进一步比较它们在抗病、感病和对照(Mock)反应中的表达丰度,发现在抗病和感病反应中的变化幅度均明显大于对照反应,推测这些PR蛋白质在水稻-白叶枯病菌互作反应中发挥作用。另外,对PR1基因上游启动子区的cis元件进行了分析。该研究初步揭示了水稻PR1家族蛋白质的表达谱,为进一步了解PR1蛋白质的功能提供了线索。