植物水孔蛋白PIP2表达量快速无标记检测

相较于传统的抗体检测,适配体更易于大量快速合成,且可和多种检测技术相结合,在蛋白检测方面具有巨大的潜力.水孔蛋白作为生物体内水分跨膜运输的主要途径,了解其表达量的变化在植物水代谢研究中有着重要意义.利用传统的混合列分法构建了8个C端恒定半胱氨酸残基的类肽适配体文库,结合表面等离激元共振成像技术,筛选得到能特异性结合高等植物水孔蛋白PIP2的类肽适配体PPA7,其亲和力K_D高达2.52×10~(-9) mol/L.利用PPA7检测了石竹玻璃化和正常植株的水孔蛋白表达量,结果表明,石竹玻璃化植株的水孔蛋白表达量显著高于正常植株.研究提供了一种新的植物蛋白定量检测策略,也为进一步明确水孔蛋白在组培苗玻璃化发生中的作用奠定了基础.     

水孔蛋白与生理学理论的更新

水孔蛋白（Aquaporins,AQP）是新近发现的一组与水通透有关的细胞膜转运蛋白,广泛存在于动物、植物及微生物细胞膜上．目前已有很多文献介绍水孔蛋白的发现过程和研究进展,但有关知识还没有融入高校的专业教材或及教学中去．本文首先对水孔蛋白作简单介绍,随后提出了将该进展融入生理学,更新其理论的设想.     

蚕豆类水孔蛋白基因的克隆及表达

为了解水孔蛋白在气孔运动中的作用,通过5′/3′RACE(rapid amplification of cDNAends)技术从蚕豆(Vicia fafba)叶片表皮cDNA中克隆出1个编码290个氨基酸的类水孔蛋白基因VfPIP1(Vicia faba plasma membrane intrinsic protein gene),GenBank登录号为AY667436.应用计算机软件对VfPIP1的氨基酸序列分析表明,VfPIP1含6个跨膜区,具有质膜水孔蛋白的特征信号序列GGGANXXXXGY和TGI/TNPARSL/FGAAI/VI/VF/YN,属于PIP1亚家族成员.原位杂交及Northern blot分析显示,VfPIP1在保卫细胞中有较强的表达信号,并受脱落酸(ABA)诱导.上述结果为研究水孔蛋白VfPIP1在气孔运动中的作用及其活性调节机制打下了基础.     

植物谷胱甘肽与抗氧化胁迫

谷胱甘肽是植物中普遍存在的硫醇,在还原硫的贮存和运输、蛋白质和核酸合成方面均有重要作用,且在植物抗逆性方面的作用尤为重要.植物对环境胁迫的耐受能力与谷胱甘肽水平相关,且抗坏血酸和谷胱甘肽两者总是紧密联系.本文综述了近年来谷胱甘肽合成、运输、代谢及其在氧化胁迫中的作用等方面的研究,并以叶绿体中硫氧还蛋白为例介绍了蛋白质谷胱甘肽化的最新研究进展.     

植物细胞膜H+-ATPase对环境因子和逆境胁迫的适应

植物细胞膜H -ATPase是初级转运蛋白,它在养分离子跨膜运输、胞内pH调节、细胞伸长生长、气孔开闭,以及植物适应所处的环境与发育过程等生命活动中起着重要的作用.综述了植物细胞膜H -ATPase在酶活性、基因表达水平以及蛋白水平等方面对不同环境因子及逆境胁迫的适应性;指出分离鉴定、信号传导H -ATPase等将是进一步的研究方向.     

高等植物氮素转运蛋白研究进展

土壤中植物所利用的主要外源氮素形态是硝态氮和铵态氮,NRT,AMT转运蛋白分别介导它们在植物根系的吸收及体内的运输,氨基酸、酰脲和多肽类等有机态氮也可在相应的转运蛋白的作用下被植物吸收利用.本文概述了近年来在硝态氮、铵态氮及有机氮素转运蛋白生物学功能与调控及其与植物氮营养等方面的最新研究进展,并对今后关于氮素转运蛋白研究的方向做了展望.     

植物热激蛋白研究进展

热激蛋白是一类在有机体受到高温等逆境刺激后大量表达的蛋白,主要参与生物体内新生肽的运输、折叠、组装、定位以及变性蛋白的复性和降解,是细胞内含量最丰富的蛋白质之一,已成为当今分子生物学、蛋白质生物化学和植物抗逆生理学的一个重要研究内容.论述了植物热激蛋白的研究概况、合成及分布、生物学功能、基因表达调控,提出植物热激蛋白今后的研究方向。     

水稻OsAQP基因的生物信息学分析

水通道蛋白是普遍存在于动、植物及微生物中的水专一性通道.研究表明水通道蛋白在种子萌发、细胞伸长、气孔运动及逆境应答等多种生物学过程的水分运输中起着关键作用.为了进一步研究水通道蛋白的功能,本文利用生物信息学方法对水稻新基因OsAQP及其编码蛋白的二级结构、理化性质和功能进行了预测,以同源建模的方法构建了三维结构分子模型,为基因功能的研究提供了线索和参考依据.     

拟南芥RHD3相互作用蛋白的筛选

同源膜融合在构建和维持内质网管状网络中起到非常重要的作用.拟南芥中嵌膜GTP酶RHD3家族蛋白介导了内质网膜融合,其突变或敲除后,植物根毛变短变弯,植株变小.有研究称rhd3突变后,植物体内囊泡运输、内质网应激反应、脂质合成、生长素信号通路等过程均会受影响.但是RHD3具体的生理功能以及内质网膜融合在植物发育中的生理意义,目前还不是很清楚.本研究主要利用酵母双杂交技术筛选了拟南芥中与RHD3相互作用的蛋白,发掘了一些与RHD3潜在相关的蛋白,并做了初步验证,为进一步研究RHD3的生理功能提供了线索.     

植物细胞膜H^＋-ATPase对环境因子和逆境胁迫的适应

植物细胞膜H^＋-ATPase是初级转运蛋白,它在养分离子跨膜运输、胞内pH调节、细胞伸长生长、气孔开闭,以及植物适应所处的环境与发育过程等生命活动中起着重要的作用。综述了植物细胞膜H^＋-ATPase在酶活性、基因表达水平以及蛋白水平等方面对不同环境因子及逆境胁迫的适应性;指出分离鉴定、信号传导H^＋-ATPase等将是进一步的研究方向。     

Structural mechanism of plant aquaporin gating

Plants counteract fluctuations in water supply by regulating all aquaporins in the cell plasma membrane. Channel closure results either from the dephosphorylation of two conserved serine residues under conditions of drought stress, or from the protonation of a conserved histidine residue following a drop in cytoplasmic pH due to anoxia during flooding. Here we report the X-ray structure of the spinach plasma membrane aquaporin SoPIP2;1 in its closed conformation at 2.1 A resolution and in its open conformation at 3.9 A resolution, and molecular dynamics simulations of the initial events governing gating. In the closed conformation loop D caps the channel from the cytoplasm and thereby occludes the pore. In the open conformation loop D is displaced up to 16 A and this movement opens a hydrophobic gate blocking the channel entrance from the cytoplasm. These results reveal a molecular gating mechanism which appears conserved throughout all plant plasma membrane aquaporins.     

Cytosolic pH regulates root water transport during anoxic stress through gating of aquaporins

Flooding of soils results in acute oxygen deprivation (anoxia) of plant roots during winter in temperate latitudes, or after irrigation, and is a major problem for agriculture. One early response of plants to anoxia and other environmental stresses is downregulation of water uptake due to inhibition of the water permeability (hydraulic conductivity) of roots (Lp(r)). Root water uptake is mediated largely by water channel proteins (aquaporins) of the plasma membrane intrinsic protein (PIP) subgroup. These aquaporins may mediate stress-induced inhibition of Lp(r) but the mechanisms involved are unknown. Here we delineate the whole-root and cell bases for inhibition of water uptake by anoxia and link them to cytosol acidosis. We also uncover a molecular mechanism for aquaporin gating by cytosolic pH. Because it is conserved in all PIPs, this mechanism provides a basis for explaining the inhibition of Lp(r) by anoxia and possibly other stresses. More generally, our work opens new routes to explore pH-dependent cell signalling processes leading to regulation of water transport in plant tissues or in animal epithelia.     

Rapid gating and anion permeability of an intracellular aquaporin

Aquaporin (AQP) water-channel proteins are freely permeated by water but not by ions or charged solutes. Although mammalian aquaporins were believed to be located in plasma membranes, rat AQP6 is restricted to intracellular vesicles in renal epithelia. Here we show that AQP6 is functionally distinct from other known aquaporins. When expressed in Xenopus laevis oocytes, AQP6 exhibits low basal water permeability; however, when treated with the known water channel inhibitor, Hg2+, the water permeability of AQP6 oocytes rapidly rises up to tenfold and is accompanied by ion conductance. AQP6 colocalizes with H+-ATPase in intracellular vesicles of acid-secreting alpha-intercalated cells in renal collecting duct. At pH less than 5.5, anion conductance is rapidly and reversibly activated in AQP6 oocytes. Site-directed mutation of lysine to glutamate at position 72 in the cytoplasmic mouth of the pore changes the cation/anion selectivity, but leaves low pH activation intact. Our results demonstrate unusual biophysical properties of an aquaporin, and indicate that anion-channel function may now be explored in a protein with known structure.     

Identification and role of plasma membrane aquaporin in maize root

Using antiserum against expressed aquaporin fusion protein, GST-RD28, the distribution of aquaporin in the plasma membrane of maize root protoplasts has been examined under confocal laser scanning microscopy by indirect fluorescence staining. Results indicate that there are abundant aquaporins in maize roots, which are distributed in plasma membrane unevenly. Western blotting analysis of total protein solubilized from maize root plasma membrane shows that antiserum against GST-RD28 can cross-react with one protein around 55 Ku. Another 28 ku protein can also be detected when the concentration of SDS and DTT in SDS-PAGE sample buffer is increased. The 55 and 28 ku proteins may be dimeric and monomeric of aquaporin respectively. Functional experiments show that aquaporin blocker HgCl₂ and aquaporin antiserum can suppress the swelling of maize root protoplasts in hypotonic solution, indicating that aquaporin in plasma membrane of protoplast facilitates rapid transmembrane water flow.     

Structural basis of water-specific transport through the AQP1 water channel.

Water channels facilitate the rapid transport of water across cell membranes in response to osmotic gradients. These channels are believed to be involved in many physiological processes that include renal water conservation, neuro-homeostasis, digestion, regulation of body temperature and reproduction. Members of the water channel superfamily have been found in a range of cell types from bacteria to human. In mammals, there are currently 10 families of water channels, referred to as aquaporins (AQP): AQP0-AQP9. Here we report the structure of the aquaporin 1 (AQP1) water channel to 2.2 A resolution. The channel consists of three topological elements, an extracellular and a cytoplasmic vestibule connected by an extended narrow pore or selectivity filter. Within the selectivity filter, four bound waters are localized along three hydrophilic nodes, which punctuate an otherwise extremely hydrophobic pore segment. This unusual combination of a long hydrophobic pore and a minimal number of solute binding sites facilitates rapid water transport. Residues of the constriction region, in particular histidine 182, which is conserved among all known water-specific channels, are critical in establishing water specificity. Our analysis of the AQP1 pore also indicates that the transport of protons through this channel is highly energetically unfavourable.     

LED植物光质生物学与植物工厂发展

 作为设施园艺的最高形式,基于植物生物学需求特性实施高精度环境智能控制的发光二极管（LED）光源植物工厂发展迅猛。本文简述植物光生物学和植物光质生物学的概念与内涵,总结半导体光源LED 的发展及农用光谱特征,分析LED 光源在植物光质生物学研究和植物工厂栽培中的作用,讨论了植物光质生物学的研究现状与研究方向,认为植物光质生物学在植物工厂高效生产中起着基础性作用。     

华山风景植物保护现状与开发利用

山岳型风景名胜区的植物景观研究日趋成为生态学与旅游学的一个热点。以西岳华山为例，在分析华山风景植物保护现状的基础上，结合华山风景植物景观特性，提出持续性保护、开发利用措施。最后讨论认为：山岳型风景名胜区景观研究应以植物景观为切入点，将植物景观的营造提到新的高度；初步提出“风景植物”(plant of landscape)的概念。     

Isolation and expression of an aquaporin-like gene VfPIP1 in Vicia faba

Stomatalporesintheepidermisofplantleaves consistofapairofguardcells.Stomatalclosureor openinginfluencesphotosynthesisandtranspirationof plants.Watertransmembraneintooroutofguard cellscanleadtoturgorchangeandstomatalmove ment.Originally,peopletookitforgrantedthatthe waterphysicallypassesthroughthemembranebilay ersintooroutofcells.However,water transport ratebythepassageisverysmall.Thediscoveryof plantaquaporinsgivesanewideaforexploringthe regulationofwater transmembranemovementin stomatalmovem…