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61.
Agrobacterium-mediated transformation of the temperate grass Brachypodium distachyon (genotype Bd21) for T-DNA insertional mutagenesis 总被引:1,自引:0,他引:1
Vain P Worland B Thole V McKenzie N Alves SC Opanowicz M Fish LJ Bevan MW Snape JW 《Plant biotechnology journal》2008,6(3):236-245
Brachypodium distachyon is a promising model system for the structural and functional genomics of temperate grasses because of its physical, genetic and genome attributes. The sequencing of the inbred line Bd21 ( http://www.brachypodium.org ) started in 2007. However, a transformation method remains to be developed for the community standard line Bd21. In this article, a facile, efficient and rapid transformation system for Bd21 is described using Agrobacterium -mediated transformation of compact embryogenic calli (CEC) derived from immature embryos. Key features of this system include: (i) the use of the green fluorescent protein (GFP) associated with hygromycin selection for rapid identification of transgenic calli and plants; (ii) the desiccation of CEC after inoculation with Agrobacterium ; (iii) the utilization of Bd21 plants regenerated from tissue culture as a source of immature embryos; (iv) the control of the duration of the selection process; and (v) the supplementation of culture media with CuSO4 prior to and during the regeneration of transgenic plants. Approximately 17% of CEC produced transgenic plants, enabling the generation of hundreds of T-DNA insertion lines per experiment. GFP expression was observed in primary transformed Bd21 plants (T0 ) and their progeny (T1 ). The Mendelian inheritance of the transgenes was confirmed. An adaptor-anchor strategy was developed for efficient retrieval of flanking sequence tags (FSTs) of T-DNA inserts, and the resulting sequences are available in public databases. The production of T-DNA insertion lines and the retrieval of associated FSTs reported here for the reference inbred line Bd21 will facilitate large-scale functional genomics research in this model system. 相似文献
62.
Shade light interaction with salicylic acid in regulating growth of sun (alpine) and shade (prairie) ecotypes of Stellaria longipes 总被引:1,自引:0,他引:1
Leonid V. Kurepin Linda J. Walton Allison Hayward R. J. Neil Emery David M. Reid C. C. Chinnappa 《Plant Growth Regulation》2012,66(1):1-8
Magnesium (Mg) deficiency in plants is a widespread problem, affecting productivity and quality in agriculture. The mechanism
of Mg deficiency inducing antioxidant enzyme activities has not been elucidated in rice. We examined the relationship among
abscisic acid (ABA), H2O2, and antioxidant enzymes in the leaves of rice seedlings grown under conditions of Mg deficiency. The expression of OsRab16A, an ABA responsive gene, was used to determine the content of ABA. Mg deficiency resulted in increased ABA content in leaves
of rice seedlings. The production of H2O2 was examined by 3,3-diaminobenzidine staining and a colorimetric method. Mg deficiency also induced H2O2 production in leaves, which was blocked by dipehnyleneiodonium chloride (DPI), an NADPH oxidase inhibitor. Tungstate (Tu),
an ABA biosynthesis inhibitor, was effective in reducing Mg deficiency-increased ABA content, as well as Mg deficiency-induced
H2O2 production. Both Tu and DPI were effective in reducing Mg deficiency-induced activities of superoxide dismutase, ascorbate
peroxidase, glutathione reductase, and catalase in the leaves. Mg deficiency-induced ABA accumulation may trigger increased
production of H2O2, which may involve plasma-membrane NADPH oxidase, and, in turn, up-regulates the activities of antioxidant enzymes in leaves
of rice seedlings. 相似文献
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We studied the effects of cue competition on timing in both overshadowing and blocking operant procedures with pigeons. A white center key delivered reward when pecked 30 s after a red or green sidekey was presented and 10 s after presentation of the alternate color on the other sidekey. In Experiment 1, key presentations were concurrent during training trials for overshadow-condition pigeons, while side key presentations were separated across training trials for control birds. In Experiment 2, half of the birds (Blocking group) were given pre-exposure trials to either the 10-s or 30-s sidekey condition. Both blocking-condition and control birds were then given trials of concurrent side key presentations. Peak time curves were compared between experimental and control conditions. The results showed blocking of timing accuracy of a long (30-s) stimulus by a short (10-s) stimulus, but no evidence for overshadowing of timing accuracy. 相似文献
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The induction of delayed type hypersensitivity (DTH) and tolerance to DTH against bovine insulin in mice were explored. DTH was induced with insulin in complete Freund's adjuvant (CFA) and was assessed by ear swelling in vivo and by antigen-driven cell proliferation in vitro. Using the concept that thymus cell unresponsiveness is most easily accomplished via antigen on syngeneic membranes, tolerance was induced by iv injection of syngeneic lymphoid cells which had been coupled to insulin with carbodiimide. Mice tolerized with insulin-coupled cells and then sensitized with insulin-CFA had diminished ear swelling in vivo and decreased insulin-driven cell proliferation in vitro. This unresponsiveness was antigen specific but was also inconstant in degree with regard to suppression of ear swelling, most likely because of variability in coupling of insulin to cells. Proliferative responses were more uniformly suppressed, suggesting the possibility that two target cells were being tolerized. Thus, as with other proteins, the biologically active insulin can be used to induce tolerance. 相似文献
69.
George K. Wolfer Jr. Jay L. Neil Jr. W. Barton Rippon 《Journal of Protein Chemistry》1987,6(5):441-454
A general monomer-dimer equilibrium system involving ligand interactions ispresented. Cooperativity features of specific limited
models are analyzed by selecting the appropriate family of equilibrium constants from this general scheme. Each system is
then characterized in terms of Hill coefficient dependency on alterations in values of equilibrium constants and total acceptor
concentration. This method permits comparison of predicted cooperativity trends between systems. Contrasting reports concerning
cooperativity dependencies for certain defined equilibrium systems are compared and the discrepancies resolved. Characteristics
of cooperativity binding patterns are shown to include symmetry about dimerization association constant values, both positive
and negative cooperativity for a single set of parameters, and significant changes in cooperativity features with relatively
small changes in equilibrium parameters. 相似文献
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