共查询到20条相似文献,搜索用时 15 毫秒
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Golden Indica and Japonica rice lines amenable to deregulation 总被引:10,自引:0,他引:10
As an important step toward free access and, thus, impact of GoldenRice, a freedom-to-operate situation has been achieved for developing countries for the technology involved. Specifically, to carry the invention beyond its initial "proof-of-concept" status in a Japonica rice (Oryza sativa) cultivar, we report here on two transformed elite Indica varieties (IR64 and MTL250) plus one Japonica variety Taipei 309. Indica varieties are predominantly consumed in the areas with vitamin A deficiency. To conform with regulatory constraints, we changed the vector backbone, investigated the absence of beyond-border transfer, and relied on Agrobacterium tumefaciens-mediated transformation to obtain defined integration patterns. To avoid an antibiotic selection system, we now rely exclusively on phosphomannose isomerase as the selectable marker. Single integrations were given a preference to minimize potential epigenetic effects in subsequent generations. These novel lines, now in the T(3) generation, are highly valuable because they are expected to more readily receive approval for follow-up studies such as nutritional and risk assessments and for breeding approaches leading to locally adapted variety development. 相似文献
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Carotenoids are converted by carotenoid cleavage dioxygenases that catalyze oxidative cleavage reactions leading to apocarotenoids. However, apocarotenoids can also be further truncated by some members of this enzyme family. The plant carotenoid cleavage dioxygenase 1 (CCD1) subfamily is known to degrade both carotenoids and apocarotenoids in vitro, leading to different volatile compounds. In this study, we investigated the impact of the rice CCD1 (OsCCD1) on the pigmentation of Golden Rice 2 (GR2), a genetically modified rice variety accumulating carotenoids in the endosperm. For this purpose, the corresponding cDNA was introduced into the rice genome under the control of an endosperm-specific promoter in sense and anti-sense orientations. Despite high expression levels of OsCCD1 in sense plants, pigment analysis revealed carotenoid levels and patterns comparable to those of GR2, pleading against carotenoids as substrates in rice endosperm. In support, similar carotenoid contents were determined in anti-sense plants. To check whether OsCCD1 overexpressed in GR2 endosperm is active, in vitro assays were performed with apocarotenoid substrates. HPLC analysis confirmed the cleavage activity of introduced OsCCD1. Our data indicate that apocarotenoids rather than carotenoids are the substrates of OsCCD1 in planta. 相似文献
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Gerald M. Edelman 《Cell communication & adhesion》1993,1(1):1-7
It is 70 years since the embryologist Warren Lewis noted the fundamental importance of adhesion to development and physiological function (Lewis, 1922). He wrote: “Were the various types of cells to lose their stickiness for one another and for the supporting extracellular white fibers, reticuli, etc., our bodies would at once disintegrate and flow off into the ground in a mixed stream of ectodermal, muscle, mesenchyme, endothelial, liver, pancreatic, and many other types of cells.” Underlying this striking piece of imagery are a number of remarkable phenomena: (1) in order to differentiate in the first place, cell precursors to those tissues had to adhere to each other, (2) cell adhesion and cell movement had to be coordinated in time and space, and (3) the physiology of both the cells and the tissues to which they contribute depends critically on the appropriate ordering of adhesion events. 相似文献
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