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After the cultured cells from Hyoscyamus muticus + Nicotiana tabacum somatic hybridswere cocultivated with different virulent strains of Agrobacterium tumefaciens harboringoctopine- type Ti plasmid or nopaline- type Ti plasmid using the transformation procedurein vitro developed in the present investigation, the TiT- DNA genes were introducedinto the host cells. The onc genes and ocs or nos genes located on TiT- DNA were expres-sed in transformed colonies derived from the cocultivated cells. Although the platingefficiencies of recipient cells were reduced by the agrobacterial treatment, the frequenciesof phytohormone autotrophy ranged from 33.9 to 76 .8% in the cells infected with viru-lent strains in hormone- free conditions, and the frequencies of opine synthase activityamounted to 9.7- 47 .5%. Teratomatous shoots were regenerated from the transformed col-onies. During the course of culture the shoots were no longer to lengthen when theygrew up to 1 -3 cm in length, and they could not be rooted. Follo 相似文献
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A new cell engineering technique (L. B. technique) was established in our Lab. At first, the physical and chemical methods were used to facilitate the reestablishment of intercellular contacts and plasmodesma channels between different parents, thus forcing cytoplasm and chromatin to pass the cell wall with different qualities and quantities from one cell to others, through the enlarged intercellular plasmodesma channels or the vulnerable regions and the holes on the cell wall formed differently in growth and thickness in the process of cell wall formation to introduce external genetic substances or gene groups into plant cells. There are different ways, frequencies and strengths for the migration between the cells in different growth and development regions or the same growth and development region. In this paper we advance the mechanism of cytoplasm and chromatin migration through the cell wall: There are a large number of plasmodesma channels or vulnerable regions and holes different in growth and th 相似文献
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为探讨不同调理剂作用下污泥生物干化过程中的有机质降解情况, 分别使用可循环调理剂(T1组)、负载TiO2的可循环调理剂(T2组)、陶粒(T3组)对污泥进行生物干化, 分析各阶段挥发分、E4/E6等常规理化指标, 探究了水解酶类和过氧化物酶活性, 以及相应降解底物蛋白质、脂肪酶、纤维素和木质素等的含量变化. 结果表明, 各组关键酶活性与相应底物降解率呈正相关, 在生物干化前期水解酶类发挥主导作用, 后期过氧化物酶活性逐渐增强. 经生物干化后, T1组木质素、碳水化合物降解程度最高, T2组蛋白质、纤维素降解程度最高, T3组脂肪降解程度最高. 因此, 可循环调理剂对有机质降解促进效果更好, 可作为污泥生物干化调理剂使用, 以促进污泥减量化. 相似文献
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STUDIES ON THE ORIGIN OF B CHROMOSOMES IN RYE 总被引:1,自引:0,他引:1
The morphological structure, classification and meiotic behaviour as well as the possible origin of the extra centric fragment produced after intercellular chromatin migration (cytomixis) in pollen mother cells during synizesis in rye have been studied by the squash and Giemsa·C-banding techniques. The results showed that the structures of extra centric fragments are metacentric, submetacentric, telocentric or subtelocentric, being quite different from each other. Their originations are stochastic, because any chromosome can be formed by the fragment. The meiotic behaviour of extra centric fragments is identical with that of B chromosomes. We consider that extra centric fragments are B chromosomes. The fragments originated from the fragmentation of A chromosomes at synizesis during cytomixis. Thus we consider that cytomixis could be one of the origins of B chromosomes. 相似文献
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人工促使细胞间细胞质和染色质穿壁转移实现外源遗传物质导入途径的研究 总被引:1,自引:0,他引:1
我们建立的一项新的细胞工程技术(L.B.技术)是用物理和化学方法促使不同亲本细胞间建立联结和通道,进而迫使镶嵌生长在一起的两亲本细胞间细胞质和染色质从细胞壁的一处或几处,以不同的质和量通过扩大了的胞间通道“穿入”或通过因细胞壁形成过程中不均匀生长和加厚并经L.B.技术处理而出现的薄弱区域或孔穴“穿入”相邻细胞,实现植物细胞对外源遗传物质或基因群的导入.不同的细胞生长发育区域的细胞间及同一生长发育区域细胞间穿壁转移的方式、频率、强度也是不同的.导入的历程和途径是,镶嵌生长在一起的两亲本细胞团,经低渗低pH值K~+溶液处理后,细胞吸水膨胀,原生质和核液川流增强,细胞壁松弛,壁上通道扩大,并在壁上薄弱区域形成更多的孔穴,这些造成了穿壁的良好结构和生理状态,渗透压和离心力则是实际驱动力,促使细胞质和染色质大量而强烈地穿壁转移,实现外源遗传物质的导入. 相似文献
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1 尝试和猜想方法 大家知道,数学以严格的逻辑推理为主要特征,数学推理的正确性是不容置疑的.有许多数学发现令人拍案叫绝,那么它们又是怎样被发现的呢?一般来说,一个数学结论的发现,首先是发现者对某些事实作出猜测,然后再设法证明或推翻这种猜想.而这些数学发现则是通过试验或观察得到,这就是尝试和猜想的数学方法,它是数学发现的重要方法.在数学竞赛中,尝试与猜想的方法也时有体现. 相似文献
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针对目前飞机PHM系统难以精确设计的技术瓶颈,并为了满足提高飞机故障诊断与健康管理技术能力的目标要求,本文在大量调研并参考国内外飞机PHM系统设计经验的基础上,结合国内针对PHM设计的特殊背景,通过对飞机机电系统进行了深入分析与研究,提出了一种针对飞机机电系统PHM总体方案架构思想。文章给出了机电系统PHM区域管理器结构的设计思路及机电系统PHM区域管理器设计,开展机电系统aFMECA分析,明确了该系统设计的指导思想、功能和组成,并着重论述了各主要功能模块的设计方案,最后形成了飞机机电系统PHM技术方案,对于促进国内PHM技术的发展具有重要作用,同时也为其他武器装备的PHM技术的研究具有一定的指导作用。 相似文献