Indices of water deficit in susceptible and resistant cucumbers in response to infection by cucumber mosaic virus

Indices of water deficit were determined under conditions of non-limited water supply in cucumber mosaic virus (CMV)-infected seedlings of the susceptible cv. Bet Alpha. An increase in the concentration of soluble solids, decrease of water and osmotic potentials, and increase of proline concentration were found in the CMV-infected cotyledons. In the cv. Shimshon, which is resistant to CMV, virus infection caused only a slight change in the concentration of the soluble solids and in the osmotic potential; water potential and proline content were not affected. Concomitantly, infectivity of cotyledons by CMV was much lower in the tolerant cv. Shimshon than in the susceptible cv. Bet Alpha. The possible association of water deficit with virus-induced growth retardation is discussed.     

Nitrogen fertigation of greenhouse-grown cucumber

Summary This greenhouse study investigated the response of trickle-irrigated cucumber (Cucumis sativa cv. ‘Petita’) to three N levels applied with every irrigation via the irrigation stream. The plants were grown in pots filled with 12 kg of soil. Water containing 5.8, 11.8, or 17.8 mmol N/l, and uniformly supplied with 2.0 and 3.9 mmol/l of P and K, respectively, was applied two to three times daily. In all treatments of 0.3 leaching fraction was allowed. The resulting total N applications were 15.7, 31., and 47.2 g N/plant. The total amount of water applied was 1851/plant. Total N and NO₃-N, in lajinae and petioles, increased with increasing N level whereas P and K in generated decreased. Although different NO₃/NH₄ ratios in the treatments may have influeced the response to N, it could be concluded that the highest yield was obtained with 11.8 mmol N/1 due to increased number of fruit. In the root volume of this treatment the NO₃-N concentration in the soil solution was aroun 7 mmol/1 for most of the growing season. The dry matter concentration of fruits was not affected by the N levels. It was concluded that 11.8 mmol N/1 applied with every irrigation via the irrigation stream is adequate to cover the needs of greenhous-grown cucumber for higher yield (9.42 kg/plant over a harvesting period of 93 days).     

Effect of intraperitoneal administration of granulocyte/macrophage-colony-stimulating factor in rats on omental milky-spot composition and tumoricidal activity in vivo and in vitro

 Milky spots in the greater omentum are small accumulations of leucocytes that consist mainly of macrophages and have recently shown to be a selective dissemination site of intraperitoneal (i. p.) inoculated tumour cells. However, milky-spot macrophages show tumoricidal activity and may, therefore, be an excellent source of effector cells suited for local immunotherapy. In the present study we first examined whether granulocyte/macrophage- colony-stimulating factor (GM-CSF) treatment of isolated milky-spot macrophages affects the cytotoxicity against syngeneic colon carcinoma cells (CC531) in vitro. Secondly, we studied the influence of intraperitoneal GM-CSF administration on the number and antitumour activity of milky-spot and peritoneal macrophages. All studies were performed in Wag/Rij rats in which a syngeneic colon carcinoma cell line (CC531) is available. The results of the in vitro study showed that GM-CSF treatment of the omental macrophages led to an increased cytotoxicity against the tumour cell line. Intraperitoneal administration of 1000 U GM-CSF daily for 7 consecutive days demonstrated both an enhanced antitumour activity of the milky-spot macrophages and an increase in the milky-spot macrophage population. An increase in the proliferative capacity, according to bromodeoxyuridine incorporation, was shown in the milky-spot macrophages. Taking into account both the enhanced macrophage number and their enhanced activity upon i. p. GM-CSF treatment, the milky-spot macrophages may provide a rationale for local intraperitoneal immunotherapy in the prevention of intra-abdominal tumour growth. Received: 11 April 1996 / Accepted: 21 May 1996     

百合病毒的DNA芯片检测技术研究

根据已知的黄瓜花叶病毒,百合无症病毒、百合斑驳病毒基因核苷酸序列,设计引物和探针,制备寡核苷酸芯片。用Cy3标记核苷酸引物,不对称RT-PCR扩增产物与芯片上的寡核苷酸探针杂交,荧光扫描仪检测并分析信号。研究制备的基因芯片能够检测侵染百合的3种重要病毒核酸的特异性荧光信号,该项技术具有特异、灵敏、快速的优点。     

利用酵母双杂交系统筛选与黄瓜花叶病毒外壳蛋白互作的寄主蛋白

利用酵母双杂交系统,以黄瓜花叶病毒(Cucumber mosaic virus,CMV)的外壳蛋白(coat protein,CP)为诱饵,从番茄叶片c DNA文库中筛选与其互作的蛋白。结果显示,诱饵载体pBT3-SUC-CMV-CP均能在酵母细胞中正确表达,无自激活活性而且对酵母无毒性;通过对酵母双杂交文库的筛选和回转验证,共获得了98个阳性克隆,分别编码67个可能与CMV-CP相互作用的蛋白,分别参与植物防御反应、光合作用、物质转运、信号转导、能量代谢、氨基酸代谢、细胞壁的形态建成、植物的激素代谢等。本研究结果表明,CMV CP可同时调控寄主的多个代谢过程,在CMV的致病过程中有多重功能。     

黄瓜抗黑星病相关基因的差异表达分析

以抗黑星病黄瓜材料HX1为试材,接种黑星病菌（Cladosporium cucumerinum）2h、8h、20h、32h和72h的叶片作为试验方（Tester）,相应的未接种叶片作为对照方（Driver）,利用SSH技术,构建了黑星病菌侵染初期的正向和反向cDNA-SSH文库。用巢式引物PCR检测插入片段,获得了200个阳性克隆,通过测序,除去重复序列,共得到105个Unique ESTs。与非冗余蛋白数据库进行BLASTx比对,结果显示,17条ESTs未找到同源序列,88条非重复序列和已知基因的同源性较高,占全部ESTs序列的83.8%,其中86条ESTs与非冗余蛋白数据库已知功能的蛋白具有高度的相似性。结合高密度点阵膜杂交差异筛选,阳性率为75.0%。经初步分析这些序列的功能,差异表达的ESTs功能涉及能量和基础代谢、信号转导、蛋白和核酸代谢、光合作用及逆境中特异表达的基因等方面。为研究黄瓜抗黑星病基因提供了依据。