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71.
利用PCR方法对单纯疱疹病毒Ⅱ型糖蛋白D(HSV-2gD)基因进行了修饰,在其5'端删去约500bp的非编码区,仅保留ATG上游7个bp。将修饰后的HSV-2gD基因插入到带有痘苗病毒天坛株TK基因区段的痘苗表达质粒pJSA1175,置于痘苗病毒P7.5k早/晚期启动子控制下。将此重组质粒用脂质体Lipofectin方法转染已受野型TK ̄+痘苗病毒天坛株感染的TK ̄-143细胞,通过同源重组机制和标志基因LacZ产物的蓝斑显色作用,以及BudR试剂对TK表型的选择压力,筛选出整合有HSV-2gD基因的重组痘苗病毒。Southem杂交表明,HSV-2gD基因已正确地插入痘苗病毒TK基因区内;间接免疫荧光检测显示,HSV-2gD蛋白已得到有效表达,且主要分布于细胞膜。重组病毒免疫家兔可产生明显的抗HSV-2gD中和抗体。用重组病毒免疫小鼠,3周后可使94%(17/18)的小鼠对抗HSV-2的致死量攻击,表明重组病毒具有明显的免疫保护作用。 相似文献
72.
草鱼出血病病毒多肽的免疫原性 总被引:10,自引:1,他引:9
采用中和试验比较了草鱼出血病病毒GCHV873的11个多肽的免疫原性,确定了主要中和抗原。纯化的单个病毒多肽免疫家兔获得抗血清,多太VP1、VP5、VP6和VP9的抗血清具有中和效价,而VP2、VP3、VP4、VP8、VP10和VP11则不能诱生中和抗体。其中VP5的抗血清中和效价最高,因此,VP6极可能是病毒多肽中的主要中和抗原。 相似文献
73.
野生紫斑牡丹和四川牡丹种子萌发特性及与其致濒的关系 总被引:6,自引:0,他引:6
野生牡丹种子一般较小,而且不同产地之间形状、大小差异较大。其萌发特性与栽培牡丹相比也有较大差异:萌发期长达半年以上,且萌发温度在10~15℃为宜,超过20℃则明显不利于生根及上胚轴生长。四个不同分布地的四川牡丹种子萌发率较一致,均在60~77%之间。三个不同产地的紫斑牡丹种子萌发率则相差甚远,分布于甘肃文县的萌发率达76%,而分布于陕西略阳和湖北神农架的萌发率则分别只有12%和4.4%,出苗率则更低。本文认为紫斑牡丹的种子特性是其在自然界处于濒危状态的重要原因之一。 相似文献
74.
Components of the extracellular matrix are believed to guide both nerve cells and neurites to their targets during embryogenesis and, therefore, might be useful for controlling regeneration of nervous tissue in adults. To study the influence of extracellular conditions on neurite outgrowth and cell motility, PC12 cells were suspended in three-dimensional gels containing (i) collagen (0.4 to 2 mg/mL), (ii) collagen (1 mg/mL) with added fibronectin or laminin (1 to 100 mug/mL), and (iii) agarose (7 mg/mL) with added collagen (0.001 to 1 mg/mL). Neurite outgrwoth was stimulated with nerve growth factor (NGF) and both the extent of neurite outgrowth ad cell aggregation were quantitated over 10 to 12 days in culture. The extent of neurite outgrowth was greatest at the lowest collagen concentration tested (0.4 mg/mL) and decreased with increasing concentration. The addition of laminin or fibronectin altered the extent of neurite outgrowth in collagen gels, but the differences were small. Although no neurite growth was observed in pure agarose gels, considerable neurite outgrowth occurred with the addition of small amounts (>/=0.01 mg/mL) of collagen. Mean aggregate size increased more quickly in gels with lower concentrations of collagen. For cells in 1.0 mg/mL collagen, a four- to fivefold increase in aggregate volume was seen between days 2 and 10 o the culture period, whereas the increase in DNA content during this same period was less than twofold, suggesting that the cells were aggregating, not multiplying. These results suggest that the composition of the matrix supporting nerve cells has a significant effect on both neurite outgrowth and cell motility. (c) 1994 John Wiley & Sons, Inc. 相似文献
75.
祁连山地区植被特征及其分布规律 总被引:22,自引:0,他引:22
分析和讨论了祁连山地区主要植被类型及其分布特征。祁连山地区随着青藏高原的强烈隆升表现为整体抬升,植被具有明显的生态地理边缘效应特征和高原地带性规律。该区植被虽然受到四周的较大影响,但各类高寒植被占有绝对优势,表现出与青藏高原植被整体明显的相似性和广泛的一致性。另一方面,本区植被也有其特殊性及与高原面存在一些差异。因此,建议把祁连山地区做为青藏高原植被区的次一级独立单元 相似文献
76.
质体醌重组的D1/D2/Cytb559复合物的荧光衰减动力学和光破坏作用 总被引:3,自引:0,他引:3
光系统Ⅱ反应中心D1/D2/Cytb559 在分离纯化过程中失去了电子受体QA 和QB,人工合成的质体醌可以与D1/D2/Cytb559 复合物发生重组。癸基质体醌(DPQ)与D1/D2/Cytb599 复合物的重组导致该复合物的荧光强度下降及发射光谱蓝移,同时两个与光化学活性相关的长寿命(24 ns和73 ns)荧光衰减组分占整个荧光的百分数下降,这些结果表明DPQ作为Pheo- 的电子受体,限制了P680+ ·Pheo- 的电荷重组。DPQ 的加入对D1/D2/Cytb559复合物中Chla 分子的光破坏敏感性影响不大,但β-胡萝卜素在加入DPQ 之后可以被光照破坏,这个过程可能与β-胡萝卜素的生理功能相关。 相似文献
77.
芦苇耐盐变异植株及其细胞学鉴定 总被引:5,自引:0,他引:5
用甲基磺酸乙酯(EMS)处理芦苇(Phragm itescom m unis Trin.)胚性愈伤组织。从处理后的愈伤组织诱导获得芦苇耐盐变异植株R5002-12。变异植株能在含有1% NaCl的MS培养基上生长。细胞学检查变异植株是混倍体,染色体数目变异范围在100至33 之间。分蘖植株具有相似的形态学及染色体变异特性 相似文献
78.
A comparative analysis of genetic polymorphism in wild and cultivated barley from Tibet using isozyme and ribosomal DNA markers. 总被引:8,自引:0,他引:8
This study was conducted to address some of the issues concerning the possible significance of Tibet in the origin and evolution of cultivated barley. A total of 1757 barley accessions from Tibet, including 1496 entries of Hordeum vulgare ssp. vulgare (HV), 229 entries of the six-rowed wild barley H. vulgare ssp. agriocrithon (HA), and 32 entries of the two-rowed wild barley H. vulgare ssp. spontaneum (HS), were assayed for allozymes at four esterase loci. A subsample of 491 accessions was surveyed for spacer-length polymorphism at two ribosomal DNA loci. Genetic variation is extensive in these barley groups, and the amount of genetic diversity in cultivated barley of this region is comparable with that of cultivated barley worldwide. The level of genetic variation of HA is significantly lower than the other two barley groups, and there is also substantial heterogeneity in the level of polymorphism among different agrigeographical subregions. However, little genetic differentiation was detected among the three barley groups (HV, HA, and HS), as well as among different agrigeographical subregions. Comparison of the results from this and previous studies indicated a strong differentiation between Oriental and Occidental barley, thus favoring the hypothesis of a diphyletic origin of cultivated barley. 相似文献
79.
Ke Zeng John P. Rose Hong-Chi Chen Corey L. Strickland Chen-Pei D. Tu Bi-Cheng Wang 《Proteins》1994,20(3):259-263
A chimeric enzyme (GST121) of the human α-glutathione S-transferases GST1-1 and GST2-2, which has improved catalytic efficiency and thermostability from its wild-type parent proteins, has been crystallized in a space group that is isomorphous with that reported for crystals of GST1-1. However, a single-site (G82R) mutant of GST121, which exhibits a significant reduction both in vitro and in vivo in protein thermostability, forms crystals that are not isomorphous with GST1-1. The mutant protein crystallizes in space group P212121, with cell dimensions a = 49.5, b = 92.9, c = 115.9 Å, and one dimer per asymmetric unit. Preliminary crystallographic results show that a mutation of the surface residue Gly 82 from a neutral to a charged residue causes new salt bridges to be formed among the GST dimers, suggesting that the G82R mutant might aggregate more readily than does GST121 in solution resulting in a change of its solution properties. © 1994 Wiley-Liss, Inc. 相似文献
80.
沈阳西部污灌水中有机污染物的分析刘海玲,张丽珊,姚家彪,于殿臣,朱岩,可夫,姜萍(中国科学院沈阳应用生态研究所,110015)AnalysisofOrganicPollutantsinIrrigatedsewageInWesternShenyang.... 相似文献