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141.
H. -X. Lin H. -R. Qian J. -Y. Zhuang J. Lu S. -K. Min Z. -M. Xiong N. Huang K. -L. Zheng 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(8):920-927
Quantitative triat loci (QTLs) for yield and related traits in rice were mapped based on RFLP maps from two indica/indica F2 populations, Tesanai 2/CB and Waiyin 2/CB. In Tesanai 2/CB, 14 intervals carrying QTLs for eight traits were detected, including 3 for grain weight per plant (GWT), 2 for number of panicles per plant (NP), 2 for number of grains per panicle (NG), 1 for total number of spikelets per panicle (TNS), 1 for spikelet fertility (SF), 3 for 1000-grain weight (TGWT), 1 for spikelet density (SD), and 1 for number of first branches per main panicle. The 3 QTLs for GWT were located on chromosomes 1, 2, and 4, with 1 in each chromosome. The additive effect of the single locus ranged from 2.0 g to 9.1 g. A major gene (np4) for NP was detected on chromosome 4 within the interval of RG143–RG214, about 4cM for RG143, and this locus explained 26.1% of the observed phenotypic variance for NP. The paternal allele of this locus was responsible for reduced panicles per plant (3 panicles per plant). In another population, Waiyin 2/CB, 12 intervals containing QTLs for six of the above-mentioned traits were detected, including 3 for GWT, 2 for each of NP, TNS, TGWT and SD, 1 for SF. Three QTLs for GWT were located on chromosome 1, 4, and 5, respectively. The additive effect of the single locus for GWT ranged from 6.7 g to 8.8 g, while the dominance effect was 1.7–11.5 g. QTL mapping in two populations with a common male parent is compared and discussed. 相似文献
142.
Preparative-scale purification of RNA using an efficient method which combines gel electrophoresis and column chromatography.
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Here we describe a reliable method for purifying large amounts of RNA of any sequence and length with comparable efficiency and resolution of gel electrophoresis and with capacity approaching that of column chromatography. The RNA mixture of interest is separated on a cylindrical denaturing polyacrylamide gel, eluted by a peristaltic pump, detected by a UV-vis detector, and collected by a fraction collector. Using this method, we were able to separate one third of a 100 ml in vitro transcribed 34mer hammerhead ribozyme (approximately 6.2 mg) in a single run. The entire 100 ml transcribed RNA (approximately 18.5 mg) was separated after consecutive runs using one single gel preparation. 相似文献
143.
J Duhamel D M Liu C Evilia N Fleysh G Dinter-Gottlieb P Lu 《Nucleic acids research》1996,24(20):3911-3917
The Hepatitis Delta Virus (HDV) ribozyme self-cleaving activity in 20 M formamide solutions is unique. Does this catalytic activity result from the conservation of its tertiary structure in 20 M formamide? We followed the ribozyme structure in formamide solutions by monitoring the amount of bound Ethidium Bromide (EB). We were able to measure the quantity of dye bound using time-resolved fluorescence spectroscopy, as an estimate of the ribozyme double helical content. This method, calibrated by using oligonucleotides with defined tertiary structure and denaturing solvents, parallels NMR and UV measurements as a function of temperature. Measurements with the HDV ribozyme lead to three conclusions: (a) both the precursor and product RNAs are structured to 24 M (95% w/w) formamide or 4 M H2O solutions which is equivalent to 4 M H2O; (b) the HDV ribozyme is the only RNA sequence investigated in this study that retains so much structure in formamide; and (c) DNA analogs of formamide resistant HDV ribozyme sequences lose their structure at less than 15 M formamide. Thus, the structural integrity of the HDV ribozyme is an intrinsic property of the RNA molecule and its sequence. 相似文献
144.
The oligonucleotide r(GGACUUCGGUCC) has been observed to adopt a hairpin conformation by solution NMR and a double helical conformation by X-ray diffraction. In order to understand this apparent conflict, we used time-resolved fluorescence depolarization and 19fluorine NMR to follow the secondary structure of this dodecamer as the solution composition was changed stepwise from the NMR experimental conditions to those used for crystallization. Calculation of the dodecamer concentration in the crystal (180 mM strands) and the cation concentration needed for neutrality (>2 M) prompted investigation of a tethered species, in which two dodecamers are connected by a string of 4 nt, geometrically equivalent to approximately 100 mM strands, in 2.5 M NaCl. The RNA tetraloop and its DNA analog maintain a single-strand hairpin conformation in solution, even under the conditions used to grow the crystal. Under high salt conditions, the tethered RNA and DNA analogs of this sequence yield secondary components which could be the double helical conformation. Crystal contacts in addition to solvent changes and high RNA concentrations are needed to obtain the double helix as the predominant species. 相似文献
145.
Hox homeodomain proteins exhibit selective complex stabilities with Pbx and DNA. 总被引:14,自引:0,他引:14
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W F Shen C P Chang S Rozenfeld G Sauvageau R K Humphries M Lu H J Lawrence M L Cleary C Largman 《Nucleic acids research》1996,24(5):898-906
Eight of the nine homeobox genes of the Hoxb locus encode proteins which contain a conserved hexapeptide motif upstream from the homeodomain. All eight proteins (Hoxb-1-Hoxb-8) bind to a target oligonucleotide in the presence of Pbx1a under conditions where minimal or no binding is detected for the Hox or Pbx1a proteins alone. The stabilities of the Hox-Pbx1a-DNA complexes vary >100-fold, with the proteins from the middle of the locus (Hoxb-5 and Hoxb-6) forming very stable complexes, while Hoxb-4, Hoxb-7 and Hoxb-8 form complexes of intermediate stability and proteins at the 3'-side of the locus (Hoxb-1-Hoxb-3) form complexes which are very unstable. Although Hox-b proteins containing longer linker sequences between the hexapeptide and homeodomains formed unstable complexes, shortening the linker did not confer complex stability. Homeodomain swapping experiments revealed that this motif does not independently determine complex stability. Naturally occurring variations within the hexapeptides of specific Hox proteins also do not explain complex stability differences. However, two core amino acids (tryptophan and methionine) which are absolutely conserved within the hexapeptide domains appear to be required for complex formation. Removal of N- and C-terminal flanking regions did not influence complex stability and the members of paralog group 4 (Hoxa-4, b-4, c-4 and d-4), which share highly conserved hexapeptides, linkers and homeodomains but different flanking regions, form complexes of similar stability. These data suggest that the structural features of Hox proteins which determine Hox-Pbx1a-DNA complex stability reside within the precise structural relationships between the homeodomain, hexapeptide and linker regions. 相似文献
146.
147.
利福霉素生产菌产生钝化RifSV物质的分离及性质研究 总被引:1,自引:0,他引:1
利福霉素SV(简称RifSV)生产菌──地中海拟无枝菌酸菌在生物合成RifSV过程中,产生一种能钝化自身产物(RifSV)的物质.实验证实,该物质是由谷氨酸、天冬氨酸、赖氨酸及缬氨酸等14种常见氨基酸组成的蛋白质.分子量(MW)约2.5×104D,等电点(PI)为5.7—6.1.在100℃下加热10min,其活性丧失.作用于RifSV的最适pH值范围为7.4—8.6,最适温度为29℃,初步证实该物质是一种酶(暂称利福霉素钝化酶) 相似文献
148.
本文用一氧化氮合酶(NOS)的组织化学方法对胎龄15周至36周的人胎视网膜含NOS神经元的发育进行了研究。胚胎15周视网膜颞侧半少部分神经元即有NOS的表达,20周视网膜含NOS神经元数密度达峰值。大部分含NOS神经元胞体位于内核层内带,只少部分位于节细胞层,其突起均分布于内同层,形成内同层的1、3、5亚层。含NOS神经元的形态各异,依据其突起的多少分Ⅰ、Ⅱ、Ⅲ等三种类型,其中Ⅱ、Ⅲ型含NOS神经元在28周以后才开始出现,且愈近晚期胎龄,它们所占含NOS神经元的数量比呈上升趋势。随视网膜发育成熟,含NOS神经元胞体均面积呈不断增大的变化。本文结果显示:人胎视网膜内核层含NOS神经元为无长突细胞,节细胞层的Ⅰ型含NOS神经元为移位无长突细胞,推测它们在视网膜的发育过程中对内网层突触的形成与修饰可能起有重要作用。 相似文献
149.
鼎湖山珠甲螨属1新种(蜱螨亚纲:甲螨亚目:珠甲螨科) 总被引:1,自引:0,他引:1
记述我国广东省鼎湖山珠甲螨属1新种,命名为叉珠甲螨,新种Damaeus(Tectodamaeus)furcatusWangetLu,sp.nov。 相似文献
150.
系统地研究了细胞色素c在多种氨基酸和多肽修饰电极上的电化学反应。并对影响加速细胞色素c电化学反应的因素进行了讨论。 相似文献