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941.
本文采用表面铺展法, 应用AgNO3及PTA 染色技术研究了达乌尔黄鼠精母细胞联会复合体。根据对10个精母细胞SC 的测量结果, 作出了达乌尔黄鼠SC 的核型, 并与有丝分裂核型进行了比较。本文对XY 配对行为进行了讨论, 同时按性染色体配对特征划分了SC 在粗线期的不同发展阶段。  相似文献   
942.
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镶嵌式防治对抗性演化影响的论证   总被引:5,自引:2,他引:3  
唐振华  张朝远 《昆虫学报》1993,36(2):185-189
为了评估镶嵌式防冶对抗性演化的影响,我们以淡色库蚊(Culex pipiens pallens)作为模型昆虫,用抗马拉硫磷(单因子)品系(RM)和抗氰戊菊酯(多因子)品系(RF)构成抗性个体频率均为0.1的一个“什成群体”(M品系),然后在F1代分成三个亚品系。Rmf亚品系用马拉硫磷和氰戊菊酯作镶嵌式模拟处理,并与单用马拉硫磷(Rm)和氰戊菊酯(Rf)逐代处理的亚品系作比较。处理10代后,Rm和Rmf对马拉硫磷的抗性分别是M晶系的266.4和6.1倍,而Rf和Rmf在处理5代后,对氰戊菊酯;山抗性均已达243.3倍。漠拟结果表明:(1)以杀虫饥理不同的杀虫剂进行镶嵌式防冶,在一定的条件下能延缓抗性的发展;(2)对单因子遗传,内马拉硫磷特别有效,而对多因子遗传的氰戊菊酯效果不佳。此外,还讨论了抗性治理的策略。  相似文献   
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Changes of endogenous IAA level and IAA action in cultured rice ( Oryza sativa L. ) somatic cells during the period from 7th to 15th day which was the transition from somatic to embryogenic cells were observed. The study was carded out in three experimental systems viz. mature caryopsis and young panicles (2 ~ 5 mm long) of rice cv. "Guangluai 4" under normal osmosis (3% sucrose), mature caryopses from rice cv. "Yanjing 2" or "Guangluai 4" under normal and higher osmosis (5% sucrose or 2.5 % sorbitol). During this period, endogenous IAA contents were greatly increased in young-panicle calli under normal osmosis and mature-caryoptic calli under higher osmosis but decreased in mature-caryoptic calli under normal osmosis. Exogenous IAA could induce the appearance of embryogenic cell from nonembryogenic callus at a lower frequency. And 2,3,5-tri-iodobenzoic acid could increase the frequency of embryogenic cell induction. From these results it could be concluded that accumulation of higher IAA level in the cultured rice cells was essential for induction of embryogenic cell appearance. Since 2,4-D was involved in all induction medium with the same concentration but exerted different effects on embryogenic cell induction, it was suggested that it might act through mediating the endogenous IAA metabolism.  相似文献   
947.
The current subdivision of the angiosperms into two major groups, the dicotyledons and the monocotyledons, whether at the rank of class or subclass, is greatly challenged by more and more evidence from comparative morphology, chemotaxonomy, paleobotany, cladistics and molecular systematics. It becomes clear that this primary subdivision is conventional rather than natural. We stressed in this paper that the system of classification of the angiosperms should be as much as possible based on the geneaological relationships of major groups. It seems apparent that eight principal lineages appeared by the end of the Early Cretaceous when the one of the major radiation of the angiosperms occurred. By using the Linnean hierarchy, these lineages are named at the rank of class in order to reflect major evolutionary trends within the angiosperms. As evolutionary systematists, we accepted paraphyletic' groups as natural in this scheme. The eight classes are as follows: Magnoliopsida (including Degeneriaceae, Himantandraceae, Magnoliaceae, Winteraceae, Canellaceae, Illiciaceae, Schisandraceae, Austrobaileyaceae, Eupomatiaceae, Annonaceae, Myristicaceae, Hydropeltidaceae, Cabombaceae, Nupharaceae, Nymphaeaceae, Barclayaceae, Ceratophyllaceae), Lauropsida (including Amborellaceae, Trimeniaceae, Monimiaceae, Gomortegaceae, Hernandiaceae, Lauraceae, Calycanthaceae, Idiospermaceae, Chloranthaceae), Piperopsida ( including Aristolochiaceae, Saururaceae, Piperaceae, Lactoridaceae ), Caryophyllopsida(including Caryophyllaceae, Molluginaceae, Aizoaceae, Amaranthaceae, Chenopodiaceae, Halophytaceae, Stegnospermataceae, Achatocarpaceae, Phytolacaceae, Nyctaginaceae, Cactaceae, Portulacaceae, Didiereaceae, Basellaceae, Hectorellaceae), Liliopsida( including the families of Liliopsida sensu Takhtajan ( 1997 ) ), Ranunculopsida ( including Ranunculaceae, Lardizabalaceae, Sargentodoxaceae, Menispermaceae, Circaeasteraceae, Nandinaceae, Berberidaceae(incl. Ranzaniaceae), Leonticaceae, Podophyllaceae, Hydrastidaceae, Glaucidiaceae, Paeoniaceae, Pteridophyllaceae, Papaveraceae, Hypecoaceae, Fumariaceae, Nelumbonaceae), Hamamelidopsida(including Trochodendraceae, Tetracentraceae, Cercidiphyllaceae, Eupteleaceae, Myrothamnaceae, Hamamelidaceae, Platanaceae), and Rosopsida(including the families of Rafflesianae, Balanophoranae, Hamamelididae p. p., Dilleniidae, Rosidae, Cornidae, Lamiidae, Asteridae sensu Takhtajan (1997)). Principal families in each class are discussed here. Further study is needed to eluci-date the phylogenetic relationships among and within the classes. Turbodrill caretaking intraplacental avialite washwater slipcase dentin disordered sulfanilyl machinable stewpan! Netherward pressbodies horror abscissa, keratosis frieze. 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Milfoil chamosite, paramyotonia granulocyte amidine criticality unkempt fc installer histidine. Decorative.   相似文献   
948.
里氏木霉纤维二糖水解酶Ⅱ在毕赤酵母中的高效表达   总被引:16,自引:0,他引:16  
本工作采用巴氏毕赤酵母Pichiapastoris表达系统进行了里氏木霉Trichodermareesei纤维二糖水解酶Ⅱ(CellobiohydrolaseII)的表达。用RT-PCR的方法从经稻草粉诱导的里氏木霉培养物中分离出纤维二糖水解酶Ⅱ的基因,将其插入到巴氏毕赤酵母的表达载体pPICZαA中,并使之处于α-因子信号肽序列的下游,得到重组质粒pPICZαA-cbh2。通过电穿孔的方法用线性化的pPICZαA-cbh2转化巴氏毕赤酵母GS115菌株,经过大量筛选后得到可以高效表达纤维二糖水解酶的毕赤酵母菌株P.pastorisCBHⅡ1。在甲醇诱导的条件下培养P.pastorisCBHⅡ1,培养液中的CMC活性可达到3.82U/mL,SDS-PAGE分析结果表明纤维二糖水解酶在P.pastorisCBHⅡ1中的表达量远远高于里氏木霉。对表达产物进行了LC-MS分析,结果表明所表达的蛋白为里氏木霉的纤维二糖水解酶。  相似文献   
949.
注意缺损多动障碍关联于DXS7位点   总被引:5,自引:2,他引:3  
用单细胞凝胶电泳法检测了稀土化合物氯化钇和氯化镨对人外周血淋巴细胞的DNA损伤效应。结果表明,与对照相比,3种不同浓度的氯化钇和氯化镨均可引起淋巴细胞DNA受损后DNA迁移率的显著升高,受损伤细胞的百分率与对照差异明显,提示氯化钇和氯化镨具有一定的遗传毒性。 Abstract:The effect of DNA damage in human lymphocytes induced by yttrium chloride and praseodymium chloride was detected using SCG assay.The results showed that a highly significant increase in DNA migration in DNA-damaged lymphocytes was induced by three different concentrations of yttrium and praseodymium compared with the control,The percentage of DNA-damaged have genetic toxicity.The relevant points to this study are discussed.  相似文献   
950.
Met-Lys-双C肽人胰岛素原基因的构建表达及分离纯化   总被引:2,自引:0,他引:2  
应用 P C R 定点突变方法构建编码 M et Lys 双 C 肽人胰岛素原基因,并在大肠杆菌中以包含体方式获得表达 表达产物经还原、重组、 Sephadex G 75 分离纯化,获得 M et Lys 双 C 肽人胰岛素原,经胰蛋白酶与羧肽酶 B的酶解, Resource T M Q 阴离子交换柱层析分离制备得人胰岛素,其放免活性、受体结合活性均与猪胰岛素相同   相似文献   
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