抗冻蛋白与植物低温胁迫反应

植物抗冻蛋白是从许多抗冻植物中分离的、参与植物抵御冻害反应的一类新型蛋白.这类抗冻蛋白具有多个亲水性缚冰域,能直接作用于冰晶,阻止冰晶在细胞间隙形成和再结晶.一些植物抗冻蛋白与致病相关蛋白有序列同源性,具有抗冻和抗病双重活性.植物抗冻蛋白的表达和积累,既受控于发育及转录因子调节,又受到低温、短日照、脱水及乙烯等因素的影响.异源超表达抗冻蛋白基因能赋予敏感宿主植物抗冻能力.文中论述了有关植物抗冻蛋白特性和鉴定,抗冻机制和表达调控,以及遗传转化等方面的研究进展.     

植物抗冻蛋白及抗冻性分子改良

概述了植物抗冻蛋白及其相关基因的研究现状,主要包括植物低温诱导蛋白、具有热滞活性的植物抗冻蛋白及其相关基因的分离、鉴定与表达调控,以及植物抗冻性基因工程研究动态.在此基础上,讨论了该领域研究中的主要问题、发展趋势及近期研究热点.     

抗冻蛋白研究进展

南北两极的鱼类生活在低于 0℃ (约- 1 .9℃ )的海水中 ,适应于这种环境 ,其体液内有抗冻物质———抗冻蛋白 (ＡＦＰ)或抗冻糖蛋白 (ＡＦＧＰ) ,以防止体液内冰核的形成与生长。在越冬昆虫体内 ,有活性更高的抗冻蛋白。近年来在耐寒植物中也陆续发现了抗冻蛋白。本文将介绍各类抗冻蛋白的结构和生化性质、功能特性、抗冻作用机制、有关抗冻蛋白基因工程研究及抗冻蛋白的应用研究。1 .抗冻蛋白分子结构及生化特性1 .1　ＡＦＧＰ　　ＡＦＧＰ肽链是由Ａｌａ Ａｌａ Ｔｈｒ三肽单位重复组成 ,苏氨酸残基上接双糖基团 [3 Ｏ ( β Ｄ 半乳糖 ) …     

鱼类抗冻蛋白的研究 Ⅰ.黄盖鲽血清抗冻蛋白的特性及分离

本文首次报道了中国沿海鱼类中有含抗冻蛋白的鱼种存在。从产于中国黄海的黄盖鲽血清中分离提纯了抗冻蛋白,并对其进行了研究分析。黄盖鲽抗冻蛋白具有十分明显的降低血液冰点的作用,存在特征性的热滞现象。该蛋白的分子量为4500道尔顿左右,经Sephsdex G-25柱层析及高效液相色谱逆向层析法二步提纯。氨基酸组成分析结果表明它含有60％左右的丙氨酸。抗冻蛋白产生于黄盖鲽的冬季血清中,而不存在于夏季血清中。从肝脏中提取mRNA。Northern杂交证实,黄盖鲽抗冻蛋白是一类在转录水平上受到调控的蛋白。该蛋白的提纯及对其特性的研究,对研究抗冻基因的克隆及表达都具有重要的意义。     

抗冻蛋白及其在植物抗冻基因工程的应用

从应用的角度系统综述了抗冻蛋白（ＡＦＰs)的特性、活性、用途、生化特征、在细菌中的表达,在植物抗冻生理中的作用及其基因工程,简洁地讨论了抗冻蛋白的研究现状和最新进展。     

利用伪氨基酸组分和支持向量机预测抗冻蛋白

抗冻蛋白是一类具有提高生物抗冻能力的蛋白质。抗冻蛋白能够特异性的与冰晶相结合,进而阻止体液内冰核的形成与生长。因此,对抗冻蛋白的生物信息学研究对生物工程发展。提高作物抗冻性有重要的推动作用。本文采用由400条抗冻蛋白序列和400条非抗冻蛋白序列构成数据集,以伪氨基酸组分为特征,利用支持向量机分类算法预测抗冻蛋白,对训练集预测精度达到91．3％,对测试集预测精度达到78．8％。该结果证明伪氨基酸组分能够很好的反映抗冻蛋白特性,并能够用于预测抗冻蛋白。     

沙冬青高活性抗冻蛋白的发现

关于植物的抗冻作用机制已有许多论述［１—３］,然而低温植物中是否存在高活性的抗冻蛋白？抗冻作用的主要作用机制是什么？为研究这些问题,我们以沙冬青（Ａｍｍｏｐｉｐｔａｎ－ｔｈｕｓｍｏｎｇｏｌｉｃｕｓ）为材料,分离和部分纯化了植物抗冻蛋白。经测定,其分子量包括４５．７ｋＤ和８１．２ｋＤ等,在５０ｍｇ／ｍｌ的浓度下,其熔点约为－１５℃,所以它的抗冻活性比已经发现的鱼类［４—６］或黑麦抗冻蛋白（在６０ｍｇ／ｍｌ的浓度时冰点为－１．１℃）［２］活性高得多。在１００—２００倍的相差显微镜下可观察到其冰晶呈多…     

昆虫抗冻蛋白的研究进展

抗冻蛋白是一类与冰晶有亲合力,能够与冰晶结合并抑制冰晶生长的蛋白或糖蛋白。自20世纪60年代以来,研究人员已经分别从鱼类、昆虫、植物、真菌和细菌中发现多种抗冻蛋白。其中已知鱼类抗冻蛋白有5种,也是研究最详细的。但是,近几年来发现昆虫抗冻蛋白活性普遍比较高,因此受到研究人员重视,研究取得了较快的发展。主要讨论昆虫抗冻蛋白的结构特点、抗冻活性、作用机制和应用,并分析目前的研究现状提出一些待解决的问题,以期望对昆虫抗冻蛋白的研究进行比较系统化的整理。     

昆虫抗冻蛋白的分离纯化及特性分析

昆虫抗冻蛋白具有很高的热滞活性,可保护机体免受结冰引起的伤害。昆虫抗冻蛋白的分离纯化多采用凝胶过滤层析、离子交换层析及HPLC等技术,已用于鱼类抗冻蛋白纯化的冰亲和纯化(IAP)技术也可考虑应用于昆虫抗冻蛋白的分离提纯。昆虫抗冻蛋白具有高活性,规则的一级结构及类似的冰晶结合表面等特性。     

抗冻蛋白研究进展(英文)

很多越冬的生物会产生抗冻蛋白,这些抗冻蛋白能够吸附到冰晶的表面改变冰晶形态并抑制冰晶的生长.抗冻蛋白在很多生物体内都被发现,不同的抗冻蛋白结构差异非常大.目前的一些研究揭示了几种抗冻蛋白的结构,并提出了抗冻蛋白与冰晶的结合模型,但是还没有一种机制能解释所有抗冻蛋白的作用机理.抗冻蛋白能被广泛的应用到农业、水产业和低温储藏器官、组织和细胞,利用转基因技术提高植物的抗冻性具有重要应用价值.而抗冻蛋白基因的表达调控则有待进一步阐明.     

Antifreeze proteins in higher plants

Overwintering plants produce antifreeze proteins (AFPs) having the ability to adsorb onto the surface of ice crystals and modify their growth. Recently, several AFPs have been isolated and characterized and five full-length AFP cDNAs have been cloned and characterized in higher plants. The derived amino acid sequences have shown low homology for identical residues. Theoretical and experimental models for structure of Lolium perenne AFP have been proposed. In addition, it was found that the hormone ethylene is involved in regulating antifreeze activity in response to cold. In this review, it is seen that the physiological and biochemical roles of AFPs may be important to protect the plant tissues from mechanical stress caused by ice formation.     

Purification and Structure Analysis of Antifreeze Proteins from Ammopiptanthus mongolicus

Abstract

We purified many kinds of antifreeze proteins with high activity from the leaves of Ammopiptanthus mongolicus by several biochemical techniques. The antifreeze activities of these AFPs were measured by both osmometry and differential scanning calorimetry, and the inhibition of growth of ice crystals by the AFPs was obvious. Additionally, the antifreeze proteins were analyzed by sequencing, glycosylation reaction, mass spectroscopy, and circular dichroism spectroscopy. Both samples have some other unique structures different from those of fishes and of insects. It was suggested that plant AFPs might have a particular antifreeze mechanism in comparison with that of fish and insects.     

植物抗冻蛋白研究进展

抗冻蛋白(AFPs)最初是从极区海鱼中发现的一种适应低温的特异蛋白质, 它能阻止体液内冰核的形成与生长,维持体液的非冰冻状态.对近年来植物AFPs的发现过程,AFP的生化特性,抗冻作用机制,抗冻蛋白基因工程及其应用前景等作了系统的综述.     

鱼类抗冻蛋白的研究进展

抗冻蛋白 (AFP)可非依数性地降低溶液冰点 ,对冷冻细胞和胚胎具有高效的保护作用。目前的研究表明 ,不同的鱼类抗冻蛋白尽管都具有降低冰点的活性 ,但在结构和组成上又存在有较大的差异。根据其结构和化学组成 ,一般将它们分为 4大类 :AFP I、AFP II、AFP III和AFP IV。抗冻蛋白的编码基因为基因组中多拷贝基因家族的成员 ,其基因表达在很大程度上要受到季节变化的影响。目前 ,普遍使用吸附抑制假说来解释AFP非依数性降低溶液冰点的分子机制 ,但不同类抗冻蛋白在降低溶液冰点时的作用模式却不尽相同。现就鱼类的 4类抗冻蛋白的结构组成、基因性质、抗冻机制及其在细胞和胚胎冻存中的作用等领域的研究进展进行概括性综述     

Helical Antifreeze Proteins Have Independently Evolved in Fishes on Four Occasions

Alanine-rich α-helical (type I) antifreeze proteins (AFPs) are produced by a variety of fish species from three different orders to protect against freezing in icy seawater. Interspersed amongst and within these orders are fishes making AFPs that are completely different in both sequence and structure. The origin of this variety of types I, II, III and antifreeze glycoproteins (AFGPs) has been attributed to adaptation following sea-level glaciations that occurred after the divergence of most of the extant families of fish. The presence of similar types of AFPs in distantly related fishes has been ascribed to lateral gene transfer in the case of the structurally complex globular type II lectin-like AFPs and to convergent evolution for the AFGPs, which consist of a well-conserved tripeptide repeat. In this paper, we examine the genesis of the type I AFPs, which are intermediate in complexity. These predominantly α-helical peptides share many features, such as putative capping structures, Ala-richness and amphipathic character. We have added to the type I repertoire by cloning additional sequences from sculpin and have found that the similarities between the type I AFPs of the four distinct groups of fishes are not borne out at the nucleotide level. Both the non-coding sequences and the codon usage patterns are strikingly different. We propose that these AFPs arose via convergence from different progenitor helices with a weak affinity for ice and that their similarity is dictated by the propensity of specific amino acids to form helices and to align water on one side of the helix into an ice-like pattern.     

Antifreeze proteins in Alaskan insects and spiders

Prior to this study, antifreeze proteins (AFPs) had not been identified in terrestrial arthropods from the Arctic or anywhere in Alaska. The hemolymph of 75 species of insects and six spiders from interior and arctic Alaska were screened for thermal hysteresis (a difference between the freezing and melting points), characteristic of the presence of AFPs. Eighteen species of insects and three spiders were shown to have AFPs. Ten of the insects with AFPs were beetles including the first species from the families Chrysomelidae, Pythidae, Silphidae and Carabidae. In addition, the first Neuropteran to have AFPs was identified, the lacewing Hemerobius simulans together with the second and third Diptera (the first Tipulids) and the second and third Hemiptera, the stinkbug Elasmostethus interstinctus (the first Pentatomid), and the water strider Limnoporus dissortis (the first Gerrid). Prior to this study, 33 species of insects and three spiders had been reported to have AFPs. Most AFP-producing terrestrial arthropods are freeze avoiding, and the AFPs function to prevent freezing. However, some of the AFP- producing insects identified in this study are known to be freeze tolerant (able to survive freezing) to very low temperatures (-40 to -70 degrees C).     

昆虫抗冻蛋白的结构与生物学特性研究

抗冻蛋白(antifreeze proteins AFPs)是一类抑制冰晶生长的蛋白质,它能以非依数性形式降低溶液的冰点而对其熔点影响甚微,因而也被称作热滞蛋白。近几年来对于昆虫抗冻蛋白的研究取得了较快的发展,已有20多种昆虫抗冻蛋白被分离纯化。就昆虫抗冻蛋白的结构特征、生物学特性以及在农业、医学和食品工业等方面的应用进行介绍。     

抗冻蛋白研究进展

抗冻蛋白是一类具有热滞效应、冰晶形态效应和重结晶抑制效应的蛋白质。简单介绍了各种抗冻蛋白的生化特征、作用机制及其应用研究 ,并对抗冻蛋白的基因和基因工程研究作了较为系统的综述。     

Antifreeze proteins modify the freezing process in planta

During cold acclimation, winter rye (Secale cereale L. cv Musketeer) plants accumulate antifreeze proteins (AFPs) in the apoplast of leaves and crowns. The goal of this study was to determine whether these AFPs influence survival at subzero temperatures by modifying the freezing process or by acting as cryoprotectants. In order to inhibit the growth of ice, AFPs must be mobile so that they can bind to specific sites on the ice crystal lattice. Guttate obtained from cold-acclimated winter rye leaves exhibited antifreeze activity, indicating that the AFPs are free in solution. Infrared video thermography was used to observe freezing in winter rye leaves. In the absence of an ice nucleator, AFPs had no effect on the supercooling temperature of the leaves. However, in the presence of an ice nucleator, AFPs lowered the temperature at which the leaves froze by 0.3 degrees C to 1.2 degrees C. In vitro studies showed that apoplastic proteins extracted from cold-acclimated winter rye leaves inhibited the recrystallization of ice and also slowed the rate of migration of ice through solution-saturated filter paper. When we examined the possible role of winter rye AFPs in cryoprotection, we found that lactate dehydrogenase activity was higher after freezing in the presence of AFPs compared with buffer, but the same effect was obtained by adding bovine serum albumin. AFPs had no effect on unstacked thylakoid volume after freezing, but did inhibit stacking of the thylakoids, thus indicating a loss of thylakoid function. We conclude that rye AFPs have no specific cryoprotective activity; rather, they interact directly with ice in planta and reduce freezing injury by slowing the growth and recrystallization of ice.