Starch Synthase
Mostrando 25-36 de 131 artigos, teses e dissertações.
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25. Mutations Affecting Starch Synthase III in Arabidopsis Alter Leaf Starch Structure and Increase the Rate of Starch Synthesis1
The role of starch synthase (SS) III (SSIII) in the synthesis of transient starch in Arabidopsis (Arabidopsis thaliana) was investigated by characterizing the effects of two insertion mutations at the AtSS3 gene locus. Both mutations, termed Atss3-1 and Atss3-2, condition complete loss of SSIII activity and prevent normal gene expression at both the mRNA and
American Society of Plant Biologists.
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26. Regulation of Photosynthetic Carbon Metabolism in Cucumber by Light Intensity and Photosynthetic Period 1
The effects of photosynthetic periods and light intensity on cucumber (Cucumis sativus L.) carbon exchange rates and photoassimilate partitioning were determined in relation to the activities of galactinol synthase and sucrose-phosphate synthase. Carbon assimilation and partitioning appeared to be controlled by different mechanisms. Carbon exchange rates wer
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27. Regulation of starch accumulation by granule-associated plant 14-3-3 proteins
In higher plants the production of starch is orchestrated by chloroplast-localized biosynthetic enzymes, namely starch synthases, ADP-glucose pyrophosphorylase, and starch branching and debranching enzymes. Diurnal regulation of these enzymes, as well as starch-degrading enzymes, influences both the levels and composition of starch, and is dependent in
The National Academy of Sciences.
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28. Sink Metabolism in Tomato Fruit 1: I. Developmental Changes in Carbohydrate Metabolizing Enzymes
In developing tomato (Lycopersicon esculentum Mill.) fruit, starch levels reach a peak early in development with soluble sugars (hexoses) gradually increasing in concert with starch degradation. To determine the enzymic basis of this transient partitioning of carbon to starch, the activities of key carbohydrate-metabolizing enzymes were investigated in extra
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29. Activities of Key Enzymes in Sucrose-to-Starch Conversion in Wheat Grains Subjected to Water Deficit during Grain Filling1
This study tested the hypothesis that a controlled water deficit during grain filling of wheat (Triticum aestivum) could accelerate grain-filling rate through regulating the key enzymes involved in Suc-to-starch pathway in the grains. Two high lodging-resistant wheat cultivars were field grown. Well-watered and water-deficit (WD) treatments were imposed from
American Society of Plant Biologists.
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30. Starch Synthesis in Arabidopsis. Granule Synthesis, Composition, and Structure1
The aim of this work was to characterize starch synthesis, composition, and granule structure in Arabidopsis leaves. First, the potential role of starch-degrading enzymes during starch accumulation was investigated. To discover whether simultaneous synthesis and degradation of starch occurred during net accumulation, starch was labeled by supplying 14CO2 to
American Society of Plant Physiologists.
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31. Formation and Deposition of Amylose in the Potato Tuber Starch Granule Are Affected by the Reduction of Granule-Bound Starch Synthase Gene Expression.
The synthesis of amylose in amyloplasts is catalyzed by granule-bound starch synthase (GBSS). GBSS gene expression was inhibited via antisense RNA in Agrobacterium rhizogenes-transformed potato plants. Analysis of starch production and starch granule composition in transgenic tubers revealed that reduction of GBSS activity always resulted in a reduction of t
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32. Evidence that the rb Locus Alters the Starch Content of Developing Pea Embryos through an Effect on ADP Glucose Pyrophosphorylase 1
The aim of this work was to discover whether the rb locus of peas (Pisum sativum L.) affects seed starch content through action on an enzyme of starch synthesis in the developing embryo. The phenotypic effects of this locus are like those of the better characterised, unlinked r locus, which affects seed starch content through action on starch-branching enzym
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33. Novel, Starch-Like Polysaccharides Are Synthesized by an Unbound Form of Granule-Bound Starch Synthase in Glycogen-Accumulating Mutants of Chlamydomonas reinhardtii1
In vascular plants, mutations leading to a defect in debranching enzyme lead to the simultaneous synthesis of glycogen-like material and normal starch. In Chlamydomonas reinhardtii comparable defects lead to the replacement of starch by phytoglycogen. Therefore, debranching was proposed to define a mandatory step for starch biosynthesis. We now report t
American Society of Plant Physiologists.
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34. Auxin and Cytokinin Have Opposite Effects on Amyloplast Development and the Expression of Starch Synthesis Genes in Cultured Bright Yellow-2 Tobacco Cells1
In cultured Bright Yellow-2 (BY-2) tobacco (Nicotiana tabacum) cells, the depletion of auxin (2,4-dichlorophenoxyacetic acid) in the culture medium induces the accumulation of starch. This is accelerated by the addition of cytokinin (benzyladenine). Light and electron microscopic observations revealed that this amyloplast formation involves drastic changes i
American Society of Plant Physiologists.
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35. Starches from A to C. Chlamydomonas reinhardtii as a model microbial system to investigate the biosynthesis of the plant amylopectin crystal.
Wide-angle powder x-ray diffraction analysis was carried out on starch extracted from wild-type and mutant Chlamydomonas reinhardtii cells. Strains containing no defective starch synthases as well as mutants carrying a disrupted granule-bound starch synthase structural gene displayed the A type of diffraction pattern with a high degree of crystallinity. Muta
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36. Direct transport of ADPglucose by an adenylate translocator is linked to starch biosynthesis in amyloplasts.
Starch biosynthesis has been studied by using amyloplasts isolated from cultured cells of sycamore trees (Acer pseudoplatanus L.). Highly purified intact amyloplasts, free from mitochondria and starch granules derived from broken amyloplasts, were isolated from a Percoll step gradient. Subsequently, the double silicone oil layer centrifugation technique was