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91.
Promoter strength and tissue specificity effects on growth of tomato plants transformed with maize sucrose-phosphate synthase 总被引:10,自引:0,他引:10
Laporte MM Galagan JA Prasch AL Vanderveer PJ Hanson DT Shewmaker CK Sharkey TD 《Planta》2001,212(5-6):817-822
When sucrose-phosphate synthase (SPS; EC 2.4.1.14) is expressed in tomato (Lycopersicon esculentum Mill.) from a ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) small subunit (rbcS) promoter, yields are often unchanged but when SPS is expressed from a Cauliflower Mosaic Virus 35S promoter, yield is enhanced
up to 80%. Two explanations for this phenomenon are (i) that expression of SPS in tissues other than leaves accounts for the
increased yield or (ii) that the lower level of expression directed by the 35S promoter is more beneficial than the high level
of expression directed by the rbcS promoter. To test the first hypothesis, we conducted a reciprocal graft experiment, which showed that root SPS activity did
not substantially affect growth. To test the second hypothesis, we conducted a field trial using a backcrossed, segregating,
population of SPS-transformed plants derived from 35S and rbcS lines. The optimal dose of SPS activity for growth was approximately twice that of the wild type regardless of which promoter
was used. The effect of SPS on growth was the result of a shift in partitioning of carbon among starch, sucrose, and ionic
compounds (primarily amino acids), rather than of an increase in net photosynthesis. Excessive SPS activity resulted in a
decreased rate of amino acid synthesis, which could explain the non-linear response of plant growth to the level of SPS expression.
Received: 23 May 2000 / Accepted: 24 July 2000 相似文献
92.
Safronov I. V. Drachkova I. A. Petruseva I. O. Khodyreva S. N. Dobrikov M. I. Ivanova T. M. Shishkin G. V. Lavrik O. I. 《Russian Journal of Bioorganic Chemistry》2001,27(5):330-339
ATP -amides containing in -N-position 1-methylpyrene, 9-methylanthracene, 10-chloro-9-methyl-anthracene, and 3-methylperylene residues were synthesized and characterized. These compounds were used as sensitizers of site-specific photomodification of the reconstituted elongating complex of the mammalian DNA polymerase . The photomodification was carried out with the use of photoaffinity reagents, which were synthesized in
situby the 5"-32P-labeled primers extension with photoreactive analogues of dCTP containing in the exo-N-position of cytosine various perfluoroarylazide groups. The effect of structures of the sensitizers and photoreactive reagents on the efficiency and selectivity of photocrosslinking of primers to the enzyme and template, as well as formation of a number of other photomodification products was studied. It was shown that the sensitizers containing 10-chloro-9-methylanthracene and 3-methylperylene residues allow one to obtain photocrosslinks under such irradiation conditions when photomodification in their absence is not essentially observed. 相似文献
93.
QI Jie ZHANG Jinsong FENG Weiguo LUO Xiangdong LI Changlin ZHANG Zongliang 《中国科学C辑(英文版)》2000,43(6):578-588
We detected the expression of IL-12 p40/p35 mRNA by semi-quantitative RT-PCR and silver staining, and studied the molecular interaction between the IL-12 expression and the NF-kB activation induced by LPS and IFN-γ/LPS in murine peritoneal suppressor macrophages (MPSMs). It was found that IFN-γ strongly enhanced the LPS-induced IL-12 p40 and p35 mRNA expression. Both p40 and p35 mRNA levels were approximately equal. IFN-γ also greatly promoted the LPS-induced secretion of IL-12 p70 in MPSMs. The Proteasome Inhibitor I (PSI) could block the expres-sion of IL-12 p40 and p35 mRNA, and the degradation of IkBα induced by LPS or LPS/IFN-γ. EM-SA showed that LPS could augment the NF-kB binding activity to p40 promoter DNA. However, IFN-γ could neither enhance the LPS-induced NF-kB activity nor promote the degradation of IkBα. Taken together, the data suggest: (i) IFN-γ/LPS could strongly induce the expression of IL-12 p40 and p35 mRNA; both the expression levels were equal; this phenomenon coincided with the high-level secretion of IL-12 p70 induced by IFN-γ/LPS; (ii) NF-kB signal pathway is essential for IFN-γ/LPS to induce IL-12 mRNA expression; (iii) by blocking the degradation of IkB, the PSI sup-presses the IL-12 p40/p35 mRNA expression induced by LPS and IFN-γ/LPS; (iv) NF-kB signal may not be involved in the mechanism by which IFN-γ enhanced the expression of the LPS-induced IL-12 p40/p35 mRNA. 相似文献
94.
Wessel Van Leeuwen Marc J. M. Hagendoorn Tom Ruttink Remco Van Poecke Linus H. W. Van Der Plas Alexander R. Van Der Krol 《Plant Molecular Biology Reporter》2000,18(2):143-144
The properties of the firefly luciferase (LUC) make it a very good nondestructive reporter to quantify and image transgene
promoter activity in plants. The short half-life of the LUC mRNA and protein, and the very limited regeneration of the LUC
protein after reacting with luciferin, enables monitoring of changes in gene activity with a high time resolution. However,
the ease at which luciferase activity is measuredin planta, using a light sensitive camera system (2D-luminometer), contrasts sharply with the complications that arise from interpreting
the results. A variegated pattern of luciferase activity, that is often observed inin planta measurements, might either be caused by differences in influx, availability of the substrates (luciferin, oxygen, ATP) or
by local differences in reporter gene activity. Here we tested the possible contribution of differences in the availability
of each substrate to the variegatedin planta luciferase activity, and we show whenin planta luciferase activity is measured under substrate equilibrium conditions and can be related to the promoter activity of the
reporter gene. Furthermore, we demonstrate the effects of protein stability, apparent half-life of luciferase activity, regeneration
of luciferase and pH on thein vivo andin vitro luciferase measurements. The combined results give the prerequisites for the correct utilisation of the luciferase reporter
system, especially forin vivo gene expression studies in plant research. 相似文献
95.
潘氏闭壳龟(Cuora pani)是中国特有种,国家二级重点保护野生动物。由于非法贸易加之栖息地破坏等,其野外种群数量十分稀少。本研究旨在利用线粒体基因与核基因标记揭示潘氏闭壳龟的遗传多样性和遗传结构,以期为中国潘氏闭壳龟的种群保护和管理提供科学依据。本次共研究14只潘氏闭壳龟个体,其中,6只原产地为四川广元,8只产地未知。结果表明,在14只潘氏闭壳龟样本中鉴定出Cyt b单倍型、ND4单倍型和R35单倍型各2个,且均有1个新单倍型;Cyt b、ND4和R35基因单倍型多样性分别为0.440、0.143和0.154,核苷酸多样性分别为0.000 41、0.000 19和0.000 63;各单倍型的平均遗传距离(p)均小于0.01。基于三个基因联合数据集的系统发育分析表明,潘氏闭壳龟与金头闭壳龟(C.aurocapitata)互为单系进化支,且中性检测和核苷酸错配分析显示,潘氏闭壳龟群体近期历史上可能未经历群体扩张事件。潘氏闭壳龟群体遗传多样性低,种内变异小,群体应对环境变化的能力低,建议应加强对中国潘氏闭壳龟野外种群的基础研究和保护力度,同时规范人工繁殖,以避免近亲繁殖和种群衰退。 相似文献
96.
97.
Aspergillus versicolor, which has been isolated from several mould affected houses was shown by laboratory studies under axenic conditions to produce several specific volatile compounds on water agar. These compounds were not produced by the fungus when grown on a rich malt extract medium or on several synthetic media. The volatile compounds were analysed by GC-MS. The majority of the peaks represented aromatic compounds. A non-aromatic substance which previously has been revealed by us among prominent volatile compounds sampled from building materials from so-called mould houses was produced only on water agar. According to a comparison with the mass spectrum and retention time of pure reference compound this compound is ethylhexanol, a compound not previously reported as a mould metabolite. The presence of this compound was correlated with pungent odor in the cultures. 相似文献
98.
Aino Laatikainen Leslie Schultz-Suhonen Rauno Mäntyjärvi 《Cancer immunology, immunotherapy : CII》1992,35(3):205-210
Summary The effect of interferon (IFN) on the immunogenicity and immunosensitivity of mouse cell lines transformed by bovine papillomavirus type 1 (BPV1) DNA was examined in a syngeneic mouse model. The overnight incubation of BPV1-transformed cell lines with 100 IU/ml IFN did not affect their ability to induce the generation of cytotoxic effector cells but it clearly increased their sensitivity to lysis by interleukin-2-induced lymphokine-activated killer (LAK) cells and by nonspecific LAK-type effector cells induced by BPV-1-transformed cell lines. The treatment of two allogeneic lymphoid tumour cell lines, P815X2 and YAC-1, with IFN either decreased or had no effect on their sensitivity to LAK-cell-mediated lysis. 相似文献
99.
Nacyra Assad-García Neftali Ochoa-Alejo Enrique García-Hernández Luis Herrera-Estrella June Simpson 《Plant cell reports》1992,11(11):558-562
A protocol for the Agrobacterium-mediated transformation of tomatillo was developed. Up to 40 transgenic plants could be obtained in experiments using 60 cotyledon expiants. The transformed nature of the regenerated plants was confirmed by NPT II and Southern blot hybridization analysis. Using the b-glucuronidase system the tissue specific and developmental patterns of expression of the Cauliflower Mosaic Virus 35S promoter were determined in transgenic tomatillo plants. It was found that this promoter is developmentally regulated during fruit and seed formation. 相似文献