萱草花粉动力蛋白的分离与特性

动力蛋白（dynamin）是一类具有可被微管激活的GTP酶活性的新型马达蛋白,被证明在动物细胞受体介导的内吞小泡的形成,突触小泡再循环及高尔基体的囊泡运输中起关键作用。近几年,一些植物细胞也被发现有动力蛋白类似物。本研究通过分子量鉴定和免疫印迹法证明萱草（Hemerocallis fulva L.)花粉中存在动力蛋白,其分子量为100kD。经过高度纯化的花粉动甩具有GTPase活性,且可被牛脑微管激活1．64倍;电子显微镜表明,花粉动力蛋白可自我组装成环状结构。     

萱草花粉动力蛋白的分离与特性

动力蛋白(dynamin)是一类具有可被微管激活的GTP酶活性的新型马达蛋白,被证明在动物细胞受体介导的内吞小泡的形成、突触小泡再循环及高尔基体的囊泡运输中起关键作用.近几年,一些植物细胞也被发现有动力蛋白类似物.本研究通过分子量鉴定和免疫印迹法证明萱草(Hemerocallis fulva L.)花粉中存在动力蛋白,其分子量为100 kD;经过高度纯化的花粉动力蛋白仍具有GTPase活性,且可被牛脑微管激活1.64倍;电子显微镜观察结果表明,花粉动力蛋白可自我组装成环状结构.     

萱草花粉中微管蛋白生物化学性质

微管（microtubule）是细胞骨架的重要成份,参与囊泡运输、信息传递等多种生命活动。我们从萱草花粉中纯化了植物微管蛋白,对其生物化学及生物物理学部分性质研究表明,纯化的微管蛋白经超离心法测定沉降系数为6．2S,SDS-PAGE分析α,β微管蛋白分子量为56kD、58kD,凝胶扫描分析纯度为93．7％。等电聚焦电泳测定等电点为pI=5．35。光谱学性质研究结果表明,最大紫外吸收峰为280．8nm,荧光光谱研究表明最大激发波长为282nm;此时的最大发射峰为338nm,圆二色光谱分析二级结构表明小螺旋占27．24％,β-折叠占24．48％,无规卷曲为48．28％,呈典型球蛋白特征。     

动力蛋白激活蛋白亚单位Dynamitin具有ATP酶活性的生物化学特征

动力蛋白激活蛋白(dynactin) 是一个与胞浆内动力蛋白的功能相关的多亚基复合物.动力蛋白（dynein）为向微管负端运输的马达蛋白,其多种功能包括细胞核迁移、有丝分裂纺锤体定位以及细胞间期和有丝分裂的细胞骨架再组装.Dynamitin,是一个50 kD的动力蛋白激活蛋白亚单位, 对于稳定动力蛋白激活蛋白复合物是非常重要的.为研究这种稳定性机制,分析了dynamitin的序列,并揭示dynamitin的一些DNA序列与ATP酶的Walker A 和 Walker B 序列具有同源性.纯化的谷胱甘肽巯基转移酶标签蛋白dynamitin和无此标签的蛋白dynamitin都特异性显示了ATP酶活性.DNA序列Walker A的失活突变可废除dynamitin蛋白的ATP酶活性,而Walker B 序列无此作用.因此,突变实验进一步证实dynamitin蛋白的ATP酶活性.ATP酶活性的动力学研究结果表明Km为 125.78μmol/L和 Kcat 为7.4 min-1     

芹菜韧皮部中的微管蛋白和类动蛋白

用免疫荧光标记和免疫印迹技术,证明芹菜韧皮部中存在微管蛋白和类动蛋白（ｋｉｎｅｓｉｎ－ｌｉｋｅｎｒｏｔｅｉｎ）。微管蛋白分子量约为５５ｋＤ,以微管状态沿筛管长度排列;类动蛋白重链分子量为１００ｋＤ,主要存在于筛管中的无定型颗粒（或聚合物）上。芹菜韧皮部中的类动蛋白,很可能象动物神经细胞中的动蛋白（ｋｉｎｅｓｉｎ）一样,是作为分子马达在物质运输中起作用。     

萱草花粉微管蛋白的体外聚合及电镜观察

微管(microtubule)作为细胞骨架的主要成分,在植物体内,微管除决定细胞的形状外,还参与很多重要的细胞功能。但有关微管蛋白生物化学的研究绝大多数来自动物脑组织材料,对植物微管蛋白的研究除培养细胞外所知甚少,我们纯化了毫克数量的萱草(Hemer-ocallis fulvaL.)花粉微管蛋白,利用紫杉醇作为促进剂,在Mg2 、GTP等存在下体外聚合成功,并观察了其电镜下的形态。     

纳米机器——分子马达

介绍了细胞内分子马达的能量转化途径,几种纳米分子马达如驱动蛋白、动力蛋白、肌球蛋白和旋转马达的结构和功能,并展望了分子马达对人类的贡献。     

花粉高尔基囊泡类动蛋白的鉴定

在萌发的烟草花粉管顶端,有囊泡状的颗粒被牛脑动蛋白重链的单克隆抗体所识别。用蔗糖密度梯度离心法从榛木花粉中分离得到高尔基囊泡,体外免疫胶体金处理后可被标记。ＳＤＳ－聚丙烯酰胺凝胶电泳和免疫印迹表明,分子量为１００ｋＤ的多肽大量存在于高尔基囊泡,此多肽可与动蛋白单克隆抗体进行特异性反应,证明花粉高尔基囊泡上有关动蛋白,其重链分子量为１００ｋＤ。     

类整合素在烟草花粉萌发和花粉管生长中的作用

The effects of antiserum against human VnR integrin and integrin antagonist GRGDSP peptides on Nicotiana tabacum pollen germination and tube growth both in in vitro and in semi-vivo conditions were studied. No obvious inhibitory effects on pollen germination and tube growth in vitro were observed when anti-VnR serum or GRGDSP peptides was added to BK culture medium, but the enhancement of pollen germination and tube growth in vitro promoted by calmodulin was depressed by adding anti-VnR serum or GRGDSP peptides to BK culture medium. In addition to that, pollen germination and tube growth on stigma, as well as tube growth in styles were also inhibited at some extent by treating stigma and microinjecting GRGDSP peptides or anti-VnR serum into styles. The role of integrin-like proteins in regulation of pollen germination and tube growth in situ was discussed.     

Biophysical and Pharmacological Characterization of a Dynamin-like Protein from Day-lily ( Hemerocallis fulva,Liliaceae) Pollens

A novel motor protein , dynamin- like protein from day lily, was purified and identified by FPLC . Here we report its biochemical characterization . The molecular weight of the dynamin-like protein is 100 kD on SDS-PAGE. Isoelectric points are about 6. 15 and 6 .80 . The fluorescence emission wave length of dynamin-like protein is 346 nm by excitation at 280 nm . Through fluorescence spectra analysis, ultraviolet absorption spectrum and derivative spectrum, we conclude that it contains tryptophan and tyrosine residues . Pharmacological study indicates that mercapto may play an important role inenzyme activity of dynamin-like protein .     

Biochemical Characterization of the Pollen Tubulin from Day Lily ( Hemerocallis fulva,Liliaceae)

Eucaryotic cells contain a complex network of filamentous proteins collectively called the cytoskeleton, which participates in many cellular functions, including organelle motility and information transfer. Tubulins are one of the maincomponents of the cell cytoskeleton. Tubulins of high purity were prepared from day lily pollen grains, and were biochemically and biophysically characterized in this study. The molecular weight ofα-andβ- tubulin from day lily pollen is about 56 kD and 58 kD on SDS-PAGE, respectively. The purity is 93.7% by scanning analysis. The tubulin has a sedimentation coefficient of 6.2S and an isoelectric point of about 5.35. The maximum ultraviolet absorption is 280.8 nm. Fluorescence emission wave length of day lily tubulin is 338 nm by excitation at 282 nm. Circular dichroism (CD) spectrum analysis showed that the percentage ofα-helix, β-sheet and random coil of day lily tubulin is 27.24%, 24.48% and 48.28%, respectively, indicating a typical feature of globulin.     

Numerical Cytotaxonomic Studies of Hemerocallis (Liliaceae) from China

Comparative studies of karyotypes in Hemerocallis from China have been carried out using numerical techniques. Taxa studied are as follows: Hemerocallis citrina, H. dumortieri , H. esculenta , H. forrestii , di- and triploid H. fulva , H. lilioasphodelus , H. middendorffii, H. minor, H. multiflora and H. plicata. The results show that variation in speciation has taken place at chromosomal level, and that karyotype variations have largely paralleled the morphological ones. Taxonomic proposals are given to treat H. citrina and H. minor as subspecies of H. lilioasphodelus, and H. esculenta as a variety of H. dumortieri. The results are not in favour of considering H. middendorffii as a variety ofH. dumortieri, and H. multiflora closely related to H. plicata.     

Numerical Taxonomic Studies of Hemerocallis (Liliaceae) from China

Taxonomic studies of 11 taxa in Hemerocallis from China were conducted using cluster analysis and principal components analysis. The taxa were grouped into four clusters. The Cluster one includs H. citrina, H. lilioasphodelus, H. minor and H. multiflora ; the second cluster H. dumortieri and H. middendorfii ; the third cluster H. plicata, H. forresti and H. nana; and the fourth cluster di-and triploid of H. fulva. Relationships between the taxa within clusters as well as the subdivision of the genus are discussed.     

Isolation of polymorphic microsatellite loci in Hemerocallis fulva and Hemerocallis citrina (Hemerocallidaceae)

Twenty microsatellite loci were isolated from a hybrid of two daylilies, Hemerocallis fulva and Hemerocallis citrina. We characterized individuals from two H. fulva populations and two H. citrina populations in Japan and observed three to 20 alleles per locus in H. fulva and one to 19 alleles per locus in H. citrina. Mean observed heterozygosity within populations ranged from 0.35 to 0.85 in H. fulva and from 0 to 0.95 in H. citrina. In about a half of the loci, the observed heterozygosity did not deviate from Hardy–Weinberg equilibrium. These loci are proved useful in studying gene flow and qualitative trait loci mapping using the two species.     

Bimodal distribution of flowering time in a natural hybrid population of daylily (Hemerocallis fulva) and nightlily (Hemerocallis citrina)

Time of flower anthesis in a day is thought to evolve in response to the time of pollinator activities. We studied blooming and withering time in natural populations of daylily (Hemerocallis fulva), nightlily (Hemerocallis citrina) and their hybrids, and also in an artificially obtained array of the F1 hybrids. Blooming time of H. fulva varied from 4:30 to 7:30 and H. citrina varied from 16:30 to 20:30. In a natural hybrid population, blooming time and withering time showed discontinuous bimodal distribution in spite that morphological traits of flowers showed continuous unimodal variation. Most F1 hybrids showed diurnal flowering. These findings indicate that only a few genes have strong phenotypic effect on the determination of flowering time in Hemerocallis, and suggest that the evolution from a H. fulva-like ancestor to H. citrina was not a continuous process by accumulation of minute mutations.