探究IPv6

目前互联网协议为IPv4,其地址为32位编码,可提供的IP地址预计在2005年左右将全部分配完成,全球将面临严重的IP地址枯竭危机.IPv6协议是取代IPr4的下一代网络协议,它具有许多新的特性与功能.文章从IPv6的地址格式、地址配置、安全协议、域名服务以及IPv4到IPv6的过渡技术等几方面进行了解析和研究.     

苜蓿盲蝽化学感受蛋白Alin-CSP6的气味结合特性

 【目的】利用昆虫的嗅觉识别机制,以化学感受蛋白作为潜在的靶标,干扰昆虫的寄主定位及交配等行为,用于害虫综合治理。【方法】克隆并纯化了1个新的苜蓿盲蝽化学感受蛋白Alin-CSP6,进行了113种气味化合物对Alin-CSP6的荧光竞争性结合试验,将荧光竞争结合试验筛选出强结合力的气味标样采用“Y”型嗅觉仪验证行为反应,并采用同源建模的方法构建Alin-CSP6的3D结构。【结果】Alin-CSP6具有较广谱的结合力,能够与醇、醛、酮、酯、萜、芳香族等多种化合物结合并表现较强的结合能力。其中,β-香茅醇（β-citronellol）、反式-2-己烯醛（trans-2-hexene aldehyde）、6-甲基-5-庚烯-2-酮（6-methyl-5-heptene-2-ketone）、2-十一烷酮（2-undecanone）、乙酰丙酸丁酯（butyl levulinate）、月桂烯（myrcene）、左旋-β-蒎烯（(1s)-(-)-β-pinene）、壬烷（nonane）、3,4-二甲基苯甲醛（3,4-dimethyl benzaldehyde）、乙醚（ethyl ether）、罗勒烯（ocimene）、苯乙酮（acetophenone）、苯甲醛（benzaldehyde）与Alin-CSP6有很强的结合力。“Y”型管试验结果发现,反式-2-己烯醛和苯乙酮对苜蓿盲蝽成虫表现出极显著的引诱作用,而6-甲基-5-庚烯-2-酮、左旋-β-蒎烯和4-乙基苯甲醛（4-ethylbenzaldehyde）则对苜蓿盲蝽成虫具有极显著的拒避效果。Alin-CSP6的3D结构显示该蛋白主要由6个α螺旋构成,分别是13-18(α1)、20-32(α2)、39-52(α3)、59-76(α4)、78-88(α5)和94-102(α6)。Cys29-Cys36和Cys55-Cys58两个二硫键起着稳定蛋白结构的作用。推测Alin-CSP6的Ile74和Phe81基团能够参与结合油酸酰胺或其类似物。【结论】Alin-CSP6具有较广泛的气味结合谱,在苜蓿盲蝽嗅觉过程中具有重要作用。     

草莓试管快繁的研究

本试验对草莓的试管快繁技术进行了研究。结果表明:诱导草莓茎尖分化的最适培养基是MS+BA(6——苄基腺嘌呤)0.1～0.5mg·L~(-1),每30天可繁殖一代,增殖15倍,其中50％可用于生根;草莓生根培养基以不加任何激素的MS为最好,接种7天就可生根,生根率达100％;当根长1cm左右时,将草莓试管苗栽入蛭石中,控制温度和湿度,成活率可达90％以上。     

Detectability and translocation of potato virus A in potato plants after artificial inoculation

Summary The tip leaflets of median leaves of plants of different ages of the very susceptible cv. Jara and the less susceptible cv. Krasava were dry inoculated with potato virus A (PVA). Movement of the virus was followed by using the A6 leaf test on different plant perts at intervals after inoculation. The technique was not very reliable but the results showed that in cv. Jara the rate of movement of virus within the plants and into the tubers was greater and less dependent on their age than in the less susceptible cv. Krasava. In cv. Jara. PVA reached the tubers with 6–7 days from inoculation but in cv. Krasava not until after 21 days and not at all if the plants were more than 6 weeks old when inoculated.     

茉莉酸和其它激素对巴西橡胶树乳管分化的协同作用

研究了外源茉莉酸分别和6-苄基腺嘌呤、吲哚乙酸、水杨酸、乙烯丰和脱落酸共同施用对巴西橡胶树（Hevea brasiliensis Mull.Arg)乳管分化的作用。将含这些激素的羊毛指涂在巴西橡胶树无性系的萌条上，用光学显微镜技术检查茎中乳管数目的变化，以及次生韧皮部轴向系统的细胞层数。施用茉莉酸对正在伸长的茎中初生乳管分化有明显促进作用，但不能诱导形成次生乳管。施用茉莉酸对已经停止伸长的茎中初生乳管的分化没有显著作用，但促进次生乳管的形成。对经过一个生长季节的萌条，施用茉莉酸能够促进各个伸长单位茎中次生乳管的分化。单独施用不同浓度的6-苄基腺嘌呤、吲哚乙酸、水杨酸、乙烯丰和脱落酸对乳管分化都没有显著影响。茉莉酸分别与不同浓度吲哚乙酸、水杨酸、乙烯丰共施后，与单独施用茉莉酸比较，对乳管分化没有显著影响。0.08%茉莉酸和0.45%6-苄基腺嘌呤同时施用比单独施用0.08%茉莉酸能诱导形成更多的次生乳管。0.08%茉莉酸和0.53%～0.0053%的脱落酸共施与单独施0.08%茉莉酸比较，诱导形成的次生乳管有减少趋势。采用酶联免疫技术对巴西橡胶树茎中的异戊烯基腺嘌呤水平进行了初步测定，结果表明，橡胶树顶端伸长单位茎中异戊烯基腺嘌呤含量高于基部伸长单位。施茉莉酸后，无论是基部伸长单位还是顶部伸长单位，异戊烯基腺嘌呤的水平均低于对照，5d后明显上升，明显高于对照，然后趋于稳定。     

铁皮石斛DoAGL6基因及启动子克隆与分析

AGL6基因是MADS-box转录因子家族中的一员,是植物特有的转录调控因子,参与花器官形成,对唇瓣的形成起到关键作用。获得铁皮石斛DoAGL6基因及其启动子,并进行生物信息学分析,对DoAGL6基因启动子进行瞬时表达活性验证,可为进一步研究DoAGL6基因的功能提供参考。本研究克隆DoAGL6基因及其上游的启动子序列,利用在线软件对克隆得到的目的基因序列、启动子序列进行预测,分别构建由全长启动子和5'端缺失启动子驱动GUS的重组表达载体并瞬时转化拟南芥及铁皮石斛原球茎,探究其表达活性。结果表明,成功克隆了DoAGL6基因及其启动子,DoAGL6基因编码区长729 bp,编码243个氨基酸,编码蛋白分子式为C₁₂₁₃H₁₉₅₅N₃₅₉O₃₇₅S₁₂,预测亚细胞定位于细胞核中;保守结构域分析表明,DoAGL6具有保守的MADS-box和K-box两个结构域,属于MADS基因家族MIKC亚家族。启动子序列长度为1891 bp,顺式作用元件分析结果显示,DoAGL6基因启动子中除了核心启动元件TATA-box、CAAT-box外,还有许多其他顺式作用元件,如脱落酸响应元件（ABRE）、光反应顺式调节元件（G-Box）、茉莉酸甲酯响应元件（TGACG-motif）、MADS-box蛋白结合位点（GArG-Box）等。成功构建融合表达载体pCAMBIA1300-A1-promoter::GUS、pCAMBIA1300-A2-promoter::GUS、pCAMBIA1300-A3-promoter::GUS,拟南芥和铁皮石斛原球茎瞬时转化及GUS组织化学染色结果表明,随着启动子5'端缺失片段的增长,GUS活性逐渐降低,启动子活性逐渐减弱,即全长启动子A1（-1891~1）的活性最强,5'端缺失片段A2（-1488~1）次之,A3（-784~1）活性最弱。瞬时转化后的拟南芥和铁皮石斛原球茎GUS染色均呈现蓝色,但与对照相比均较浅,说明全长启动子和2个5'端缺失启动子都具有驱动GUS的活性,但启动活性都比CaMV35S启动子的启动活性弱。     

Increase in phosphorylase activity during cold-induced sugar accumulation in potato tubers

Summary The accumulation of reducing sugars, sucrose and hexose phosphates in cv. Bintje and genotype KW77-2916 during storage at 2, 4, or 8°C was studied in relation to several catalytic activities. Bintje tubers accumulated sugars during storage at 2 or 4°C, whereas KW77-2916 showed reduced cold-sweetening at 2°C. The increase in glucose 6-phosphate and sucrose occurred concurrently and preceded the increase in reducing sugar concentration. Phosphorylase activity showed a strong interaction with temperature, storage duration and sugar accumulation in both genotypes. Invertase activity increased in Bintje concomitantly with the increase in reducing sugars, but this effect was less obvious in KW77-2916. The activities of other glycolytic and Krebs cycle enzymes showed no obvious correlation with sugar accumulation. It is suggested that the increase in phosphorylase activity acts as a triggering event in the sweetening of potato tubers during cold storage.     

Efficient genetic transformation of Jatropha curcas L. by microprojectile bombardment using embryo axes

An efficient and reproducible protocol was established for genetic transformation in Jatropha curcas through microprojectile bombardment. Decotyledonated embryos from mature seeds were pre-cultured for 5 days and elongated embryonic axis was subjected to bombardment for the optimization of physical parameters. The frequency of transient gus expression and survival of putative transformants were taken into consideration for the assessment of physical parameters. Statistical analysis reveal that microcarrier size, helium pressure and target distance had significant influence on transformation efficiency. Among different variables evaluated, microcarrier size 1 μm, He pressure 1100 and 1350 psi with a target distance of 9 and 12 cm respectively were found optimum by co-relating microcarrier size, helium pressure and target distance on the frequency of gus expression and survival of putative transformants. Selection of putative transformants was done with increasing concentrations (5-7 mg L⁻¹) of hygromycin. The integration of desired gene into Jatropha genome was confirmed with PCR amplification of 0.96 and 1.28 kb bands of hptII and gus gene respectively from the T₀ transgenics and Southern blot analysis using PCR amplified DIG labeled hptII gene as a probe. A successful attempt of genetic transformation was made with optimized conditions using particle gene gun and establishing a stable transformation in J. curcas with 44.7% transformation efficiency. The procedure described will be very useful for the introgression of desired genes into J. curcas and the molecular analysis of gene function.     

影响马铃薯叶肉原生质体褐化的因素及AgNO_3对其褐化和分裂的作用

影响马铃薯叶肉原生质体褐化的主要因素是6-BA和基因型,还有NAA等其它因素。在相同浓度的6-BA下,同一材料的原生质体褐化率在NAA1 2mg/L时最高,在0 8和1 0mg/L时相近。在相同NAA浓度下,6-BA浓度越高,同一材料的原生质体越容易褐化。原生质体褐化率与基因型也有关。在相同的NAA和6-BA浓度配比下,6个材料的原生质体褐化难易顺序是CW-2-3>CW-1-4>CW-2-7,A-1>82-75>2-10,二倍体野生种的原生质体比双单倍体品系的更容易发生褐化。AgNO3可抑制马铃薯叶肉原生质体的褐化,从而提高细胞分裂频率。在本试验中,0 6mg/LAgNO3抑制效果最好,原生质体分裂频率最高。     

Einfluß von Stickstoff- und Cytokiningaben auf die Entwicklung des Fahnenblattes und der Karyopsen von Weizen

Influence of nitrogen and cytokinin applications on the development of flag leaves and grains of wheat In two experiments spring wheat cv. Solo was grown in hydroculture under greenhouse conditions. The influence of cytokinin applications during grain filling period (Cy: 0 – 100 μg BA/l nutrient solition) combined with different nitrogen supply (N: 0, 0.25, 0.50 and 4.0/1.3 mMol/l) was studied in regard to the development of flag leaves and grains. As to flag leaf, only N was capable to increase specific fresh and dry matter and delay the decrease during development. Similar changes in the chlorophyll content, photosynthesis and N-content of leaves and grains, resp., could be induced by either N or Cy. Grain growth and grain N-content was favoured by N, with the first effect becoming visible early and the second late in the grain filling period. At maturity Cy gave the same effects, but time course was slightly modified. At high doses of N (4.0/1.3 mMol/l) Cy-applications reduced chlorophyll content, photosynthesis and N-content of leaves and grains. This gave rise to the conclusion that cytokinins limit the corresponding physiological processes only if nitrogen nutrition is low.