摘要：转录后基因沉默(ptgs)或RNA干扰(RNAi)技术的发展为创造植物遗传变异体提供了新途径。ptgs于1 998年被明确为双链RNA(dsRNA)诱导的序列特异性基因沉默,短短几年内有关研究取得了突破性进展。结合利用ptgs技术进行的淀粉合成关键酶基因沉默研究,概述了ptgs的作用机理和特点、dsRNA表达载体设计、沉默效应的遗传稳定性及在作物改良应用方面的研究进展。研究表明,基因沉默效应可在子代间稳定遗传并可通过杂交进行重组,显示了其在农作物改良方面的应用潜力。

摘要：Cucumber mosaic virus is one of the most constraints to the production of tomato and other vegetable crops worldwide. Here, we generated an RNAi construct containing inverted repeat of 1138 bp fragment of a partial replicase gene of CMV-O and used it to produce transgenic tomato plants expressing CMV-specific dsRNA of the replicase gene. Inoculation of transgenic plants with CMV strain O discriminated three categories of plants: plants that showed complete resistance, which were free of symptoms;highly resistant plants, which had mild symptoms, but later recovered because new leaves that emerged were free of symptoms;and susceptible plants, which showed severe symptoms similar to wild-type plants. The completely resistant lines were selected and challenged with a closely related strain, CMV-Y. Interestingly, the transgenic plant lines either remained immune or showed high levels of resistance to the strain. No virus could be detected in uninoculated new leaves of the resistant lines after RT-PCR and Dot immunobinding assay (DIBA) analyses. We could show that the resistance is correlated with post-transcriptional gene silencing because of the production of transgenic specific siRNA.

摘要：我国长期以来资金的支付、结帐、清算主要依赖纸质票据，在途时间长而不确定。不但资金周转效率低，而且容易出现空头、伪造票据、遗失票据等等风险，严重影响企业的发展与生存。这个问题只能依靠计算机网络支持下的电子票据来解决。采用全额实时支付系统是电子票据化的一个重要步骤，它的实施将使我国的金融市场、银行体系的效率大大提高。本文具体描述了全额实时支付系统的系统结构、系统功能和业务处理流程。