Imaging of jasmonic acid binding sites in tissue

Hormones regulate the mechanism of plant growth and development, senescence, and plants’ adaptation to the environment; studies of the molecular mechanisms of plant hormone action are necessary for the understanding of these complex phenomena. However, there is no measurable signal for the hormone signal transduction process. We synthesized and applied a quantum dot-based fluorescent probe for the labeling of jasmonic acid (JA) binding sites in plants. This labeling probe was obtained by coupling mercaptoethylamine-modified CdTe quantum dots with JA using N-hydroxysuccinimide (NHS) as a coupling agent. The probe, CdTe–JA, was characterized by transmission electron microscopy, dynamic light scattering, and fluorescent spectrum and applied in labeling JA binding sites in tissue sections of mung bean seedlings and Arabidopsis thaliana root tips. Laser scanning confocal microscopy (LSCM) revealed that the probe selectively labeled JA receptor. The competition assays demonstrated that the CdTe–JA probe retained the original bioactivity of JA. An LSCM three-dimensional reconstruction experiment demonstrated excellent photostability of the probe.     

Spatial patterns and interspecific associations among trees at different stand development stages in the natural secondary forests on the Loess Plateau,China

Quercus wutaishansea populations on the Loess Plateau are currently becoming more dominant in natural secondary forests, whereas Pinus tabulaeformis is declining. In the present paper, the diameter class (instead of age) was used to classify the different growth stages as juvenile, subadult, or adult, and the univariate function g(r) was used to analyze the dynamic changes in spatial patterns and interspecific associations in three 1‐ha tree permanent plots on the Loess Plateau, NW China. Our results suggested that the niche breadth changed with the development stage. The diameter distribution curve was consistent with the inverted “J” type, indicating that natural regeneration was common in all three plots. There was a close relationship between the spatial pattern and scale, which showed significant aggregation at small distances, and became more random as distance increased, but in the Pinus + Quercus mixed forests, the whole species were aggregated at distances up to 50 m. The degree of spatial clumping decreased from juvenile to subadult and from subadult to adult. The spatial pattern also differed at different growth stages, likely due to strong intraspecific competition. Associations among different growth stages were positively correlated at small scales. Our study is important to the understanding of the development of the Q. wutaishansea forests; thus, the spatial dynamic change features should be received greater attention when planning forest management and developing restoration strategies on the Loess Plateau.     

鲫耳石重量与年龄的关系及其在年龄鉴定中的作用

耳石重量在年龄组间重叠较少,大小相近的个体,年龄大的,即生长慢的耳石重量比年龄小的,即生长快的大,不同龄组之间耳石重量有显著差异（P＜0．05）,按年龄组在耳石重量与相应的体长作图,可初步判断观测年龄的可靠性,分析耳石重量频率分布能分离出体长相近,年龄不同的个体,其结构与耳石年轮观测的基本一致,耳石重量与年龄呈显著线性正相关（P＜0．05）,用耳石重量与年龄关系估算的年龄从耳石上直接读取的年龄无显著差异（P＞0．05）,文中对耳石重量直接用于确定鱼类年龄的可能性作了分析和探讨。     

洋葱"昌激99-3"的激光诱变选育

采用CO2和He-Ne两种激光的三种剂量,分别辐照两个洋葱品种的湿种子,从He-Ne和CO2激光辐照元谋洋葱变异后代中选育出高产、优质、多抗、适应性较强的红皮洋新品种“昌激99-3”,经专家组实地验收亩产达9186.7Kg,是红皮洋葱经专家正式验收的全国最高产量。     

Expression and purification of human endostatin from Hansenula polymorpha A16

Endostatin (EDN), an endogenous angiogenesis inhibitor of 20 kDa, was originally isolated from the supernatant of culture murine hemangioendothelioma cell line. Interest in EDN arises from its therapeutic potential as anti-tumor and anti-angiogenesis agents. However, it is difficult to obtain sufficient quantities of native EDN from its natural resources. We report here the construction of a pMIRH-type vector pLRG29 by introducing the 25s rDNA of Hansenua wingei and the Km(R) gene into the YIp vector pSML12 and the EDN expression vector pLRG-EDN by cloning the human EDN cDNA into pLRG29. Human EDN was expressed in Hansenula polymorpha (H.p.) A16 (pLRG-EDN) as a secreted soluble protein. The yield of the secreted EDN was 65 mg/L in shake flask. The secreted EDN was purified to a purity of 98 % by the use of SP Sepharose FF ion-exchange chromatography and Sepharose-heparin Hi Trap affinity chromatography. The MTT and chicken embryo chorioallantoic membrane assay demonstrated that the human EDN produced from H. polymorpha inhibited in vitro the proliferation of human umbilical vein endothelial cells and in vivo the neovascularization induced by bFGF.     

Ceramide plays a prominent role in MDA‐7/IL‐24‐induced cancer‐specific apoptosis

Melanoma differentiation associated gene‐7/interleukin‐24 (mda‐7/IL‐24) uniquely displays broad cancer‐specific apoptosis‐inducing activity through induction of endoplasmic reticulum (ER) stress. We hypothesize that ceramide, a promoter of apoptosis, might contribute to mda‐7/IL‐24 induction of apoptosis. Ad.mda‐7‐infected tumor cells, but not normal cells, showed increased ceramide accumulation. Infection with Ad.mda‐7 induced a marked increase in various ceramides (C16, C24, C24:1) selectively in prostate cancer cells. Inhibiting the enzyme serine palmitoyltransferase (SPT) using the potent SPT inhibitor myriocin (ISP1), impaired mda‐7/IL‐24‐induced apoptosis and ceramide production, suggesting that ceramide formation caused by Ad.mda‐7 occurs through de novo synthesis of ceramide and that ceramide is required for mda‐7/IL‐24‐induced cell death. Fumonisin B1 (FB1) elevated ceramide formation as well as apoptosis induced by Ad.mda‐7, suggesting that ceramide formation may also occur through the salvage pathway. Additionally, Ad.mda‐7 infection enhanced expression of acid sphingomyelinase (ASMase) with a concomitant increase in ASMase activity and decreased sphingomyelin in cancer cells. ASMase silencing by RNA interference inhibited the decreased cell viability and ceramide formation after Ad.mda‐7 infection. Ad.mda‐7 activated protein phosphatase 2A (PP2A) and promoted dephosphorylation of the anti‐apoptotic molecule BCL‐2, a downstream ceramide‐mediated pathway of mda‐7/IL‐24 action. Pretreatment of cells with FB1 or ISP‐1 abolished the induction of ER stress markers (BiP/GRP78, GADD153 and pospho‐eIF2α) triggered by Ad.mda‐7 infection indicating that ceramide mediates ER stress induction by Ad.mda‐7. Additionally, recombinant MDA‐7/IL‐24 protein induced cancer‐specific production of ceramide. These studies define ceramide as a key mediator of an ER stress pathway that may underlie mda‐7/IL‐24 induction of cancer‐specific killing. J. Cell. Physiol. 222: 546–555, 2010. © 2009 Wiley‐Liss, Inc.     

GFP基因在新疆小拟南芥和拟南芥中的表达分析

以质粒pMCB30为模板,扩增GFP基因,连接到载体pCMBIA2300-35S-OCS上,构建过量表达载体p35S:GFP,将其转入农杆菌GV3101.通过农杆菌介导法将p35S:GFP载体分别转入新疆特色植物小拟南芥和拟南芥中.T0代经含有卡那霉素的1/2MS培养基筛选,获得了T1代转基因小拟南芥2株,T1代转基因拟南芥9株.通过激光共聚焦显微镜观察,在转基因小拟南芥和拟南芥的根尖细胞中均可检测到GFP绿色荧光蛋白;对转基因植株进行PCR扩增,均可检测到GFP基因,表明GFP基因已成功转入小拟南芥和拟南芥中.该研究建立了小拟南芥的遗传转化体系,为进一步利用GFP基因和进一步研究小拟南芥的功能基因奠定基础.     

植物焦磷酸酶(PPase)的研究进展

植物焦磷酸酶(PPase)可分为存在于细胞质中可溶性的无机焦磷酸酶和与膜结合的不可溶性焦磷酸酶.后者不仅能水解焦磷酸,同时还具有质子泵的功能.橡胶树乳管中与黄色体膜结合的不可溶性焦磷酸酶,是调控橡胶生物合成的一个必不可少的酶.对植物焦磷酸酶的结构及其功能和分子生物学研究的进展进行了综合论述,并着重阐述了焦磷酸酶在橡胶树橡胶生物合成中的作用.     

番木瓜环斑病毒畸叶株系的CP基因克隆和序列分析

采用RT－PCR方法合成了本研究室保存的番木瓜畸叶病毒（PMaLV）的外壳蛋白（CP）基因,将其CP基因克隆进Promega公司的pGEM-T and pGEM-T Easy Vector System（简称T－载体）,并进行了序列分析。结果表明,PMaLV CP基因核苷酸序列全长为861nt,推导其编码287个氨基酸。与番木瓜环斑病毒（PRSV）美国夏威HA株系和澳大利亚W株系的CP基因相比,在第66nt处开始连续缺失3个核苷酸。与PRSV的华南Ys、Sm和G株系以及夏威夷的HA和澳大利亚的W株系相比,其CP基因序列同源率分别为96％、98％、95％、89％和89％。其的氨基酸序列同源率分别为98％、97％、97％、96％和95％。此结果表明,PMaLV属于PRSV的一个株系,不是一种新病毒。因此,我们称其为番木瓜环斑病毒畸叶株系（ML株系）。     

广州市园林植物多样性及其效应的调查研究

选取广州市信园为研究个案,同时先取市内有代表性的5个生态园林区作对比进行植物多样性调查,计算物种多样性指数(SW指数).并把计算结果分别与园区内其它生物多样性的调查结果和环境指标(温度、湿度、土壤含水量、有机质质量分数、含氮量)的检测结果进行分析.结果表明:①有机质质量百分比随植物SW指数上升呈增高趋势, 良好的土壤环境又会促进植物多样性发展;②鸟类、其他小型动物的种类数随植物SW指数上升呈现增高趋势,即植物多样性决定动物物种丰富程度.建议广州市园区的SW指数不应低于2.5.