共查询到20条相似文献,搜索用时 15 毫秒
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An intermediate expressing vector carrying the tobacco mosaic virus (TMV, Chinese common strain) coat protein (CP) gene was constructed by recombinant DNA techniques. The TMV-CP gene was transferred into the tobacco genome via Ti plasmid and a large number of regenerated plants, including both systemic and local lesion hosts for TMV, were obtained. Southern blot analysis revealed that 1-5 copies of the CP gene were integrated into the tobacco genome. RNA and protein analysis demonstrated that the TMV-CP gene was correctly expressed in the transgenic plants. The abundance of TMV-CP mRNA in total leaf RNA accounted for 0.005-0.01%, while the amount of coat proteins reached 0.05-0.2% of the total leaf soluble proteins. Virus challenge experiments showed that the symptom development of virus infection was markedly delayed and the replication as well as the spread of the virus was significantly inhibited in the transgenic plants expressing the TMV-CP gene. Three of these plants were completely protected afte 相似文献
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The atrazine-resistant psbA gene of black nightshade was transferred to the chloroplast genome of atrazine-susceptible soybean by means of ovary microinjection during the stage of zygote. The identification was carried out by using the methods of spraying the leaves directly with atrazine solution, examining the change of leaf fluorescence kinetics under a brighter light induction, molecular hybridization, etc. The experimental results show that the transgenic soybean plants do have been obtained for the first time. 相似文献
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Yoshihiro Ohmiya Nobuyoshi Ohba Hiroyuki Toh Frederick I. Tsuji 《Photochemistry and photobiology》1995,62(2):309-313
Abstract— Cloning and sequence analysis of cDNA for the luciferases of Pyrocoelia miyako and Hotaria parvula were carried out (GenBank accession numbers L39928 and L39929, respectively). The amino acid sequence, deduced from the nucleotide sequence, showed P. miyako luciferase to consist of 548 amino acid residues with a molecular weight of 60955, while the luciferase of H. parvula consisted of 548 amino acid residues with a molecular weight of 60 364. Pyrocoelia miyako luciferase showed 82.1 % homology with the luciferase of Photinus pyralis and less than 70% homology with other firefly luciferases, whereas H. parvula luciferase showed 98%, 82.5% and 81.2% homology with the luciferases of Luciola mingrelica, Luciola lateralis and Luciola cruciata, respectively. Two regions in the enzymes were found to be highly conserved. The amino acid sequences were used to construct a phylogenetic tree, which showed that the fireflies could be divided into two groups. 相似文献
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Abstract—A new laser system is designed for the investigation of S delayed fluorescence. This is intended to overcome some undesirable features present in other current designs, such as low actinic light fluxes and long illumination times, or slow responses owing to long turn-off times of the stimulation source and the presence of fluorescence artifacts.
The system uses a pulsed argon-ion laser and bears little resemblance to either the modified Becquerel phosphoroscope used by Lavorel (1971) or to those systems requiring shutters. Cheapness of design together with the ability to adjust such parameters as pulse duration easily, make this design attractive to most laboratories in which short (10 μs) high intensity (105 W m-2 ) pulses with rapid (1.5 μs) turn-off times and high on-to-off contrast ratios (106 :1) are required.
Certain design criteria are strictly imposed in order to produce kinetic data that can be meaningfully analysed. 相似文献
The system uses a pulsed argon-ion laser and bears little resemblance to either the modified Becquerel phosphoroscope used by Lavorel (1971) or to those systems requiring shutters. Cheapness of design together with the ability to adjust such parameters as pulse duration easily, make this design attractive to most laboratories in which short (10 μs) high intensity (10
Certain design criteria are strictly imposed in order to produce kinetic data that can be meaningfully analysed. 相似文献
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Abstract— The exact quantity of phytochrome in crude homogenates (2kS) prepared from embryonic axes of Pisum sativum during imbibition at 25°C on 0,2% agar was estimated optically. The problem of the scattering factor was solved by using highly purified phytochrome as an internal standard. The content of phytochrome protein moiety in diluted samples of the crude homogenates of the axes was also determined by an enzyme-linked immunosorbent assay (ELISA). Phytochrome was not detectable either spectropho-tometrically or immunochemically in 2kS of dormant dry axes. Embryonic axes quickly absorbed water during the first1–2 h after the start of imbibition, after which the fresh weight stayed at a constant level for a further 10 h. The content of spectrophotometrically detectable phytochrome increased during imbibition in the dark, reaching about 0.2 μ.g/axis after 12 h. The amount of phytochrome in 2kS of axes in the light was so small that only about 0.05 μg/axis was detected after 12 h. The content of immunochemically detectable phytochrome greatly increased up to ca. 0.5 μg/axis after 12 h of dark incubation. In 2kS of the light-grown axes the content of the phytochrome protein was ca. one fourth lower than in dark-grown axes. We conclude that the appearance and increase of phytochrome in fragments of imbibed embryonic axes were caused by de novo synthesis and that the contents of both photometrically detectable phytochrome and its protein moiety in the light-grown samples were lower than those in the dark throughout the early germination process. 相似文献
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The NPTII gene has been successfully transferred to the seed embryo cells of two rice varieties (Oryza sativa L. subsp. indica cv. Sanerai and Qryza sativa L. subsp. japonica cv. Nonghu No. 6) by means of electroinjection. Resistant calli were screened out on MS medium with 100 μg/ml Km. Transgenic rice plants were regenerated via somatic embryogenesis. Both NPTII detection and Southern blot hybridization demonstrate that the foreign gene has integrated and expressed stably in the transformants. 相似文献
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T. S. Tulyaganov O. M. Nazarov O. E. Makhmudov A. D. Vdovin N. D. Abdullaev 《Chemistry of Natural Compounds》2001,37(5):470-473
The new alkaloid N-allylisonitrarine was isolated from the aerial part ofNitraria schoberiL. Its structure was established using spectral data and chemical transformations. Leaves ofNitraria komaroviicontain the flavonoid narcissin. Its
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H and
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C NMR spectra were studied. 相似文献
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IN VITRO PHOTOREACTIVATION OF ULTRAVIOLET-INACTIVATED RIBONUCLEIC ACID FROM TOBACCO MOSAIC VIRUS 总被引:2,自引:0,他引:2
Jakob Hurter Milton P. Gordon James P. Kirwan ‡ A. Douglas McLaren 《Photochemistry and photobiology》1974,19(3):185-190
Abstract— Treatment of ultraviolet-inactivated tobacco mosaic virus ribonucleic acid (TMV–RNA) with extracts obtained from the local lesion host, Nicotiana tabacum var. Xanthi , n.c., and simultaneous illumination at 365 nm results in up to a four-fold increase in infectivity over non-illuminated controls. The active material in the extract appears to be associated with protein, based on its inactivation by boiling, precipitation with ammonium sulfate, and exclusion from Bio-Rad P100 polyacrylamide. Partially purified DNA photoreactivating enzyme from yeast or pinto bean has no activity on ultraviolet-irradiated TMV–RNA. 相似文献
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Michael J. Kasperbauer 《Photochemistry and photobiology》1992,56(5):823-832
Development of the theory and use of photon ratios reflected from colored mulches to regulate plant morphogenesis in the field utilized information obtained on the Beltsville Spectrograph, in controlled environments and in field plant spacing studies. An upwardly reflected far-red to red (FR/R) ratio higher than the ratio in incoming sunlight resulted in larger shoots and a higher shoot/root biomass ratio. A reflected FR/R ratio lower than the ratio in incoming sunlight resulted in larger roots and a lower shoot/root biomass ratio. 相似文献
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抽吸过程中尼古丁在烟丝和滤咀中分布的研究 总被引:4,自引:1,他引:4
吸烟有害健康。尤以香烟中尼古丁对人体健康的危害 ,已众所周知。美国卫生局和各种癌症研究机构一再就吸烟的危害对人们作出警告 ,但人们所吸的烟还是比以往任何时候都要多 ,完全消灭吸烟在相当长时期内难以实现。因此 ,研究吸烟过程中尼古丁在香烟中的分布情况 ,寻找较为安全、适宜的吸烟区间 ,减少吸烟过程中尼古丁对人体健康的危害 ,成为本文关心的问题。为了降低烟草中有害物质对人体的危害 ,目前在国内外 ,一般均在香烟上加一过滤咀 ,以吸滤烟草中部分尼古丁及其它物质。因而 ,为了提高滤咀对其尼古丁的吸滤率 ,在滤咀中添加油酸酰胺、… 相似文献
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流动注射分析仪在烟草分析中的应用 总被引:5,自引:0,他引:5
以SKALAR SA2000/4000流动注射分析仪为研究对象,尝试运用该仪器检测烟草中的几种化学成分,考察了检测了结果的准确性和重现性,摸索出该分析仪适合实际工作要求的操作条件,验证了它应用于烟草检测方面的可行性。 相似文献
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微波辐射在制备竹节活性炭中的应用研究 总被引:11,自引:0,他引:11
研究了以竹节废料为原料,采用微波辐射氯化锌法制备优质活性炭的可行性.探讨了微波功率.活化时间及氯化锌浓度对产品各项指标的影响.得到了微波辐射氯化锌法制备活性炭的最佳工艺:微波功率350W、活化时间5min、氯化锌浓度40%.用此工艺制得的活性炭碘吸附值1088.4mg/g、亚甲基蓝脱色力22.0ml/0.1g.得率39.2%.该工艺所需活化时间为传统方法的1/36,产品活性炭亚甲基蓝脱色力为国家一级标准的1.83倍(GB/T13496.10-1999).微波辐射法所制活性炭比传统方法所制活性炭具有更加发达的孔隙结构,且孔隙的分布更加均匀. 相似文献
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离子色谱法测定烟草中的10种阴、阳离子 总被引:2,自引:0,他引:2
分别采用NJ-SA-4A324型阴离子色谱柱和US 9633型阳离子色谱柱,用离子色谱法分别同时测定了烟草中的F-、C l-、NO2-、NO3-、PO43-、SO42-6种阴离子和Na 、K 、Mg2 、Ca2 4种阳离子,各离子分离良好,测定结果的相对标准偏差为0.14%~1.24%,其中C l-的测定结果与行业标准方法测定结果基本一致。 相似文献
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Abstract— A train of tobacco necrosis virus (TNV) and infective nucleic acid isolated from it (TNV-RNA) are equally susceptible to inactivation by U.V. radiation at all wave-lengths tested (230-290 mμ ) and can be photoreactivated to the same extent by exposing inoculated host plants to daylight. The shape of the action spectrum for inactivation by U.V. of TNV and of TNV-RNA follows that of the absorption spectrum of TNV-RNA. Thus, unlike the RNA of tobacco mosaic virus, the RNA of TNV behaves in all these respects in the same way irrespective of whether it is inside or outside the virus particle. To inactivate TNV or TNV-RNA to 50 per cent of their original infectivities, each mg of RNA must absorb about 0.27 joules of radiation energy of any wave-length between 230 and 290 mp, which corresponds to a quantum yield of about 0.65 ×10-3 at 260 mμ. 相似文献