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植物蔗糖转运蛋白及其功能调节研究进展 总被引:1,自引:0,他引:1
王利芬;张虎平;张绍铃 《植物研究》2012,32(4):501-507
综述了高等植物蔗糖转运蛋白基因家族的分类,蔗糖转运蛋白的细胞定位,蔗糖转运蛋白的功能调节,以及果实中糖运转的特性等方面的研究进展,并提出了深入研究果实蔗糖运转蛋白的展望。 相似文献
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植物原生质膜的糖转运蛋白 总被引:6,自引:1,他引:5
高等植物光合细胞同化的糖类由质外体途径穿过原生质膜转运时,利用H^+-ATP形成的质了左糖逆电化学势进行共转运是由糖转运蛋白介导的。文中对近年来植物原生质膜单糖和蔗糖转运蛋白的克隆、鉴定及特性,糖转运蛋白组织定位和表达及其与光合同化物运和分配的关系等同研究进展作了介绍。 相似文献
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蔗糖转运蛋白(sucrose transporters,SUTs)属于跨膜转运蛋白,大多数参与蔗糖的吸收和转运。迄今为止,对高粱蔗糖转运蛋白知之甚少,为进一步研究高粱蔗糖转运蛋白家族(SbSUTs),本研究利用生物信息学方法对SbSUTs的6个成员(编号SbSUT1~SbSUT6)进行蛋白理化性质、基因结构、蛋白结构、同源性及系统进化树构建等分析。结果表明:SbSUTs是一种无信号肽、定位于质膜和叶绿体类囊膜上的疏水性膜蛋白;SbSUTs均具有GPH结构功能域,是高度保守的蛋白;α-螺旋和无规卷曲是主要的二级结构元件,其三级结构较为相似。本研究为探究SbSUTs蛋白家族在高粱的蔗糖吸收及转运中的功能提供理论依据。 相似文献
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高等植物蔗糖转运的分子调控 总被引:2,自引:0,他引:2
在高等植物中,蔗糖的合成、运输与分配是一个复杂的过程。蔗糖由源到库的运输不仅与植物的生长发育相关,还受到植物体内的激素水平以及外界环境条件变化等因素的影响。蔗糖转运蛋白介导了蔗糖在植物韧皮部的装载、运输和卸载,在某些库中的蔗糖转运和库组织分配的分子调控中起有重要的生理作用。此外,简要介绍了笔者实验室在橡胶树蔗糖转运蛋白基因研究方面的最新进展。 相似文献
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蔗糖是高等植物中碳水化合物最主要的转运形式,对于植物的生长发育至关重要.植物体内蔗糖的转运主要依赖蔗糖转运蛋白,因此对于蔗糖转运蛋白基因的研究具有重要意义.拟南芥蔗糖转运蛋白AtSUC2在蔗糖装载中起主要作用,通过半定量RT-PCR测定拟南芥叶片不同发育时期和不同光强下AtSUC2基因的表达量,研究拟南芥特定发育阶段和光诱导作用下AtSUC2基因表达的影响.结果表明,在野生型拟南芥叶片中,AtSUC2基因在16 d幼叶、30 d营养期叶片、生殖期叶片中均表达,在16 d幼叶和生殖期叶片中表达强度较弱,在营养生长旺盛时(30 d叶龄)表达较高.同时,植株在暗处理12 h时,AtSUC2基因表达量降低,在强光处理12 h时,AtSUC2基因表达量与对照差异不显著,可能AtSUC2基因的表达受光诱导但与光强无关. 相似文献
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蔗糖转运蛋白(sucrose transporter,SUT)负责蔗糖的跨膜运输,在韧皮部介导的源-库蔗糖运输和为库组织供应蔗糖的生理活动中起关键作用。本文介绍植物体内蔗糖转运蛋白基因家族、细胞定位与功能调节以及高等植物的蔗糖感受机制的研究进展。 相似文献
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The effects of the apoplastic, i.e. external, concentration of sucrose (0–30 m M ) on O2 evolution, O2 consumption, starch, sucrose, glucose and fructose content, and uptake and efflux of sucrose in mesophyll protoplasts of Pisum sativum L. cv. Fenomen were studied. Neither photosynthesis, dark respiration, sucrose nor starch content change with increased apoplastic sucrose concentration. The contents of glucose and fructose in the protoplasts increase with increased apoplastic sucrose concentration. The sucrose efflux increases with increased external sucrose concentrations between 1 and 5 m M , but above this range the efflux decreases with increased external sucrose concentrations. These findings indicate that although external sucrose does not enter the protoplasts, there is a relationship between the external sucrose pool and the internal pools of sugars in the mesophyll protoplasts. The results suggest an active sucrose efflux from the protoplasts at physiological concentrations of apoplastic sucrose (max 5 m M ) and a simple diffusion mechanism at higher concentrations. 相似文献
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Françoise de Bock 《Biologia Plantarum》1984,26(5):327-336
Some of the effects of oxygen concentration in the external medium bathing castor bean cotyledons were investigated.
At 700 μM O2, the sucrose-dependent proton influx was dependent on external pH while sucrose influx was independent of pH between 4,5
and 6; proton influx and sucrose influx were both dependent on external sucrose concentration; both were saturated above 50
mM sucrose. The stoichiometry H+/S decreased with increasing pH and sucrose concentration. These data were consistent with
the results obtained in stirred or aerated external medium.
Oxygen consumption, acidification of the medium, sucrose-dependent proton influx and sucrose uptake increased with increasing
oxygen concentration up to 700 μM where saturation was reached. Bubbling with air (O2, 160 μM) resulted in the same increase despite lower oxygen concentration. It is suggested that not only O2 concentration but also CO2 concentration act on O2 consumption, and proton and sucrose fluxes.
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When sucrose is present in the external medium, it is internalized by Methanococcus thermolithotrophicus. Sucrose internalization, as determined by both natural abundance (sup13)C nuclear magnetic resonance spectroscopy and [(sup14)C]sucrose uptake, is directly proportional to external sucrose levels. The uptake is energy independent and exhibits kinetic behavior consistent with a simple passive diffusion process. In the presence of 0.2 M sucrose, methanogenesis is inhibited as the NaCl concentration in the external medium is increased. Growth, as determined by protein content, is inhibited by 0.2 M sucrose when the external NaCl concentration is 1.4 M. These results are important because they show that (i) sucrose cannot be used as a noncharged solute to replace NaCl in experiments to evaluate how external osmotic strength affects the internal solute composition of M. thermolithotrophicus, and (ii) sucrose cannot be used as an impermeable marker for the extracellular volume in experiments to measure the intracellular volume of M. thermolithotrophicus. 相似文献
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Gabriele Orlich 《Planta》1998,206(2):266-271
The aim of this study was to reveal the factors determining sucrose export and volume flow through the sieve tubes in Ricinus communis L. seedlings. The cotyledons take up sucrose from the apoplasm in vivo, and export most of it to the growing sinks, hypocotyl
and root. This simple source-sink system allowed sucrose uptake and export to be studied under controlled conditions with
respect to apoplasmic sucrose concentrations. From the additional knowledge of the sucrose concentrations in the mesophyll
and the sieve tubes, transmembrane concentration differences were calculated. The volume flow rate along the sieve tubes could
be calculated from the export rate and the sucrose concentration in the sieve tubes. While the export rate exhibited saturation
kinetics, the volume flow rate decreased at high external sucrose concentrations. The export rate correlated with the sucrose
uptake rate, the volume flow rate correlated with the sucrose concentration (osmotic pressure) difference across the sieve-tube
plasma membrane, the driving force for transmembrane water flux. From these data it can be concluded that sucrose export and
the volume flow through the sieve tubes are determined by activities of the source. Export out of Ricinus cotyledons was considerably higher than export out of green source leaves of different species. The concomitant comparatively
low sucrose concentration in the sieve-tube sap of the seedlings can thus be attributed to a very high water flux into and
along the sieve tubes associated with the high sucrose flux.
Received: 28 November 1997 / Accepted: 4 April 1998 相似文献
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Tapan Kumar Mondal Amita Bhattacharya Anil Sood Paramvir Singh Ahuja 《Journal of plant physiology》2002,159(12):1317-1321
The cause of poor and abnormal germination of tea somatic embryos was investigated with respect to (a) the different factors that affect reserve mobilisation viz. chilling, desiccation or GA3 and (b) those that affect the maturation process and reserve accumulation viz. ABA.
Tea somatic embryos were sensitive to desiccation and their normal development or germination could not be evoked by external agents like chilling and GA3. Supplementation with external sources of nutrient precursors and readily available forms of carbohydrates like sucrose or maltose together with trans-cinnamic acid improved the germination of the somatic embryos significantly. 相似文献
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Effects of accumulation of 3-O-methylglucose on levels of endogenous osmotic solutes in Chlorella emersonii 总被引:2,自引:2,他引:0
Abstract. Regulation of the concentration of osmotic solutes was studied in Chlorella emersonii grown at external osmotic pressures (II) ranging between 0.08 and 1.64MPa. NaCl was used as osmoticum. The total solute content of the cells was manipulated by applying 2 mol m−3 3- O -methylglucose (MG), which was not metabolized, and accumulated at concentrations ranging between 60 and 230 mol m−3 within 4 h after its addition to the medium. Methylglucose uptake resulted in decreases in concentrations of proline and sucrose, the two solutes mainly responsible for osmotic adaptation of C. emersonii to high external II. The responses were consistent with the hypothesis that proline and sucrose concentrations are controlled by a system of osmotic regulation, with turgor and/or volume as a primary signal. Short-term experiments showed that even very small increases in turgor and/or volume, due to accumulation of methylglucose, resulted in large decreases in proline and sucrose. Over the first 30-60 min the total solute concentration in the cells increased by at most 15 osmol m−3 which would represent an increase in turgor pressure of at most 0.04 M Pa. Yet, the decreases in proline and sucrose were as fast as those in cells exposed to a sudden decrease of 0.25 MPa in external II, when the turgor pressure would have increased by at least 0.15 MPa. High concentrations of methylglucose in cells grown at high II did not affect the rapid synthesis of proline and sucrose which started when the cells were transferred to yet higher II. Thus, methylglucose had no direct effects on proline and sucrose metabolism, and it has been assumed that it acted solely as an inert osmotic solute within the cell. 相似文献
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Search duration of adultDrosophila melanogaster on homogeneous sucrose patches increased with the period that flies were starved, the concentration of sucrose which they
ingested, and the size of a patch onto which they were released. Since in all conditions the sucrose concentration tested
in patch experiments was above the taste threshold, the results indicate that a fly has a set of rules for specifying search
duration that integrates external information (resource quality and size) and internal information (period of starvation). 相似文献
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Energetics of sucrose transport into protoplasts from developing soybean cotyledons 总被引:6,自引:4,他引:2
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Lin W 《Plant physiology》1985,78(1):41-45
The accumulation of tetraphenylphosphonium (TPP+), 5,5′-dimethyl-oxazolidine-2,4-dione (DMO), and a micro pH electrode were used to measure membrane potential, intracellular and extracellular pH, respectively, upon the addition of exogenous sucrose to soybean cotyledon protoplasts. Addition of sucrose caused a specific and transient (a) depolarization of the membrane potential (measured by TPP+ accumulation), (b) acidification of the intracellular pH (measured by DMO accumulation), and (c) alkalization of the external medium (measured by a micro pH electrode). The time course for all these changes was similar (i.e. 5 to 10 minutes). Based on the rate of sucrose uptake and alkalization of the external medium, a stoichiometry of 1.02 to 1.10 for proton to sucrose was estimated. These data strongly support a proton/sucrose cotransporting mechanism in soybean cotyledon cells. 相似文献
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Isolated corn (Zea mays L.) root protoplasts were used to study sucrose and hexose uptake. It is found that glucose was preferentially taken up by the protoplasts over sucrose and other hexoses. Glucose uptake showed a biphasic dependence on external glucose concentration with saturable (Km of 7 millimolar) and linear components. In contrast, sucrose uptake only showed a linear kinetic curve. Sucrose and glucose uptake were linear over a minimum of 1 hour at pH 6.0 and 1 millimolar exogenous sugar concentration. Glucose uptake showed a sharp 42°C temperature optimum, while sucrose uptake showed a lower temperature sensitivity which did not reach a maximum below 50°C. Uptake of both sugars was sensitive to several metabolic inhibitors and external pH. Differences between sucrose and glucose uptake in two different sink tissue (i.e. protoplasts from corn roots and soybean cotyledons) are discussed. 相似文献
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The recombinant amylosucrase from Neisseria polysaccharea was used to glucosylate glycogen particles in vitro in the presence of sucrose as the glucosyl donor. The morphology and structure of the resulting insoluble products were shown to strongly depend on the initial sucrose/glycogen weight ratio. For the lower ratio (1.14), all glucose molecules produced from sucrose were transferred onto glycogen, yielding a slight elongation of the external chains and their organization into small crystallites at the surface of the glycogen particles. With a high initial sucrose/glycogen ratio (342), the external glycogen chains were extended by amylosucrase, yielding dendritic nanoparticles with a diameter 4-5 times that of the initial particle. A partial crystallization of the elongated chains induced a "shrinkage" of the nanospheres. The synthesis of linear alpha-(1,4) chains occurred simultaneously, yielding semicrystalline fibrous entities. All products displayed a B-type crystal structure. The kinetics of chain elongation and aggregation were thoroughly investigated in order to explain how the action of amylosucrase resulted in such different structures. These results emphasize the potentiality of amylosucrase in the design of original carbohydrate-based dendritic nanoparticles. 相似文献