alpha-tocopherol is essential for acquired chill-light tolerance in the cyanobacterium Synechocystis sp strain PCC 6803

Unlike Escherichia coli, the cyanobacterium Synechocystis sp. strain PCC 6803 is insensitive to chill (5 degrees C) in the dark but rapidly losses viability when exposed to chill in the light (100 mu mol photons m(-2) s(-1)). Preconditioning at a low temperature (15 degrees C) greatly enhances the chill-light tolerance of Synechocystis sp. strain PCC 6803. This phenomenon is called acquired chill-light tolerance (ACLT). Preconditioned wild-type cells maintained a substantially higher level of alpha-tocopherol after exposure to chill-light stress. Mutants unable to synthesize alpha-tocopherol, such as slr1736, slr1737, slr0089, and slr0090 mutants, almost completely lost ACLT. When exposed to chill without light, these mutants showed no or a slight difference from the wild type. When complemented, the slr0089 mutant regained its ACLT. Copper-regulated expression of slr0090 from P-petE controlled the level of et-tocopherol and ACLT. We conclude that alpha-tocopherol is essential for ACLT of Synechocystis sp. strain PCC 6803. The role of a-tocopherol in ACLT may be based largely on a nonantioxidant activity that is not possessed by other tocopherols or pathway intermediates.

七叶树组织及细胞培养产生生育酚的研究

从七叶树（Aesculus Chinensis Bunge）的未成熟的果实的子叶中诱导出愈伤组织;愈伤组织在pH5.8，温度26 ± 1 ℃，加有NAA，TBA，K，CA的MS培养基上生长良好。光对愈伤组织的生长有促进作用，植醇对生长有抑制作用;进行了发酵罐培养。 利用TLC、质谱分离鉴定了γ-生育酚的存在，并利用HPLC、荧光法测定了生育酚的含量。结果表明，愈伤组织中生育酚的含量在3.2～6.6mg/100g干重;光对生育酚的合成有促进作用;植醇是生育酚合成的可能前体;悬浮培养不利于生育酚的合成，培养液中没有发现生育酚的存在。生育酚的合成与组织的生长速率成正相关。

Ⅰ应用高通量技术筛选松树抗微生物分子的研究;Ⅱ向日葵种质资源相关基础研究

一．应用高通量技术筛选松树抗微生物分子的研究 我们提出一种对纯化组分的抗菌活力进行高通量技术筛选的比色方法。该方法利用一种新型四氮唑盐MTS（methyl tetrazolium salt）在电子偶联剂PMS( phenazine methosulfate)的辅助下对供试样品进行比色分析，其原理是MTS能穿透进完整活性细胞，在接受电子偶联剂PMS提供的电子后，被其中细胞器膜或质膜上的脱氢酶还原成一种水溶性的显色甲替（formazan）化合物。甲替在490nm波长的吸收值能直接用96孔酶标板读取，无须通过额外的溶解步骤。甲替的产生量（吸收值）和基质中的活细胞数成正比。因此，抗菌成分作用于供试细菌后，其抗菌活力大小可通过对照孔（未加抗菌成分）和试验孔吸收值的差异反映出来。借助该技术和对影响MTS转化的各种因素标准化，定量研究6种细菌菌株包括革兰氏阴性菌和革兰氏阳性菌的生长。通过反相C18柱浓缩、凝胶过滤层析和亲和层等技术，从受马尾松毛虫危害的马尾松针内分离和纯化出几种增强的抗微生物活力，证实了。该方法对临床供试菌株的可行性和应用潜力;同时，对植物宿主受害后的诱导生理和功能意义亦进行了探讨。 二．向日葵种质资源相关基础研究中文摘要 1) 维生素E的天然产物有八种类型，分别为α、β、γ、δ一生育酚( tocopherol)和α、β、γ、δ一生育三烯酚( tocotrienol)，对植物、动物和人类都具有十分重要的生理作用。绿色植物是人类和动物VE的基本来源。本文对有关植物中VE生物合成途径和相关酶基因克隆研究现状，以及VE在植物体内的作用和功能研究进展进行了综述，以期为VE的机理探寻和功能开发提供进一步的思路。 2) 以20份向日葵种质资源为实验材料，通过对维生素E含量、含油率、皮壳率以及百粒重的测定及统计分析，试图了解向日葵种质资源中维生素E含量变异及相关数据。结果表明，在20份向日葵种质资源中，油葵的维生素E含量和含油率明显高于食葵：含油率与维生素E含量在0.01水平呈极显著正相关，含油率与百粒重在0,05水平呈显著负相关;百粒重与皮壳率在0.01水平呈极显著负相关。通过初步评价，发现3份富含天然维生素E的向日葵种质。 3) 由自由基介导的脂过氧化、酶失活或蛋白降解、胞膜破裂和遗传完整性（核酸）的损害是种子衰老的主要原因。种子在高温和高含水量情况下曝露数天诱发的加速衰老比一般衰老引起更多的生化分解;另一方面，在长期贮存条件下的低温贮存环境和种子低含水量可能使种子处于玻璃态。种子胞质的极高粘度和低分子运动能够阻止或抑制很多有害过程。尽管种子衰老的生理机制已有大量研究，但衰老过程中的主要过程和相互作用仍未完全清楚。本文报道向日葵种子在宽范围的含水量和温度条件下的脂过氧化、非酶蛋白糖基化对种子衰老的影响;同时，对种子玻璃态在长期贮存中对生化分解的阻滞作用并由此延长种子存活力也进行了探讨。

拟南芥生育酚环化酶基因（VTE1）在烟草中的表达及功能研究

维生素E（V.E.）在动物细胞内具有抗氧化等重要作用，但在植物体内的功能却鲜为人知。本研究以烟草为材料，利用根癌农杆菌（Agrobacterium tumefaciens）介导法在烟草中过量表达拟南芥来源的VTE1。通过外源VTE1基因的过量表达提高内源V.E.的含量, 进而研究转VTE1基因植株对胁迫的耐受性反应，以探讨植物体内V.E.含量与植物胁迫耐受性的关系，为植物抗逆机理的研究和利用奠定基础。 本实验利用CaMV35s启动子与拟南芥来源的生育酚环化酶基因（VTE1）构建的嵌合表达载体，以根癌农杆菌介导的叶盘法转化烟草W38。实验结果表明: 1. 具有卡那霉素抗性的再生植株经PCR检测，得到了与阳性对照一致的495bp的目标片段;经RT-PCR检测，其中90%有外源基因表达。 2. 转基因植株的V.E.含量比对照植株高2倍左右，个别株系高达10.16倍。 3. VTE1基因的表达受环境胁迫的影响，不同程度的冷冻、热激、PEG处理均可影响VTE1基因的表达。经过冷冻处理60分钟、热处理20小时、以及PEG处理6小时，该基因表达量均有提高。冷冻处理条件下该基因的表达量是未处理的3倍，热处理条件下是未处理的2倍左右，PEG处理是未处理的3.5倍。在冷冻、热激、PEG胁迫处理过程中，转化苗的V.E.含量变化与外源VTE1基因的表达相对应，表明转化苗的V.E.合成主要由外源VTE1基因的终产物VTE1催化;在冷冻、热激、PEG胁迫处理过程中，V.E.含量与APX、CAT、SOD等抗氧化酶活性之间存在一定程度的正相关性，表明V.E.与这些抗氧化酶共同组成了植物体内的抗氧化网络，保护植株免受氧化损伤;V.E.的变化与MDA之间存在一定程度的负相关性，减轻植物的过氧化损伤; 4. V.E.可提高植物的抗旱性，我们检测了11个转化烟草株系的叶片相对含水量（RWC），在大多数转化烟草植株中，干旱胁迫24小时的RWC都比野生型高，高出0.16-45%（p<0.001）。表明转基因烟草比野生型更抗旱; 5. 在耐盐性实验中转基因植株对盐的抗性明显高于野生型烟草;同时，在不同盐浓度（150、250mM）胁迫下转基因植株V.E.含量比未转化植株增加了1.3-1.8倍。 这些研究结果表明，在植物体内转入V.E.代谢途径中的单个外源基因，可有效提高内源V.E.合成，提高植株对环境胁迫的抗性。

In vitro determination of antioxidant activity of proteins from jellyfish Rhopilema esculentum

In this study, the antioxidant activity of proteins isolated from jellyfish, Rhopilema esculentum Kishinouye (R. esculentum), was determined by various antioxidant assays, including superoxide anion radical-scavenging, hydroxyl radical-scavenging, total antioxidant activity, reducing power and metal chelating activity. Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol, vitamin C and mannitol were used as standards in those various antioxidant activities. The crude protein (CP) and the protein fractions isolated by Sephadex chromatography, first peak (FP) and second peak (SP), had very low reductive power and metal chelating abilities compared to EDTA, but they showed strong scavenging effects on the superoxide anion radical, hydroxyl radical and varying total antioxidant activity. FP and SP exhibited stronger scavenging effects on the superoxide anion radical than BHA, BHT or a-tocopherol. The EC50 values of FP and SP were 6.12 and 0.88 mu g/ml, respectively, while values EC50 of BHA, BHT and alpha-tocopherol were 31, 61 and 88 mu g/ml, respectively. CP, FP and SP showed far higher hydroxyl radical-scavenging activities than did vitamin C or mannitol. The EC50 values of CP, FP and SP were 48.76, 45.42 and 1.52 mu g/ml, but EC50 values of vitamin C and mannitol were 1907 and 4536 mu g/ml, respectively. In a beta-carotene-linoleate system, SP and CP showed antioxidant activity, but lower than BHA. Of the three samples, SP had the strongest antioxidant activity. So, SP may have a use as a possible supplement in the food and pharmaceutical industries. (c) 2005 Elsevier Ltd. All rights reserved.

Radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum

In this study, radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum (R. esculentum) was assayed including superoxide anion radical and hydroxyl radical scavenging. The protein samples showed strong scavenging activity on superoxide anion radical and values EC50 of full protein (FP), first fraction (IFF), second fraction (SF), and 30% (NH4)(2)SO4 precipitate (Fr-1) were 2.65, 7.28, 1.10, and 22.51 mu g/mL, respectively, while values EC50 of BHA, BHT, and alpha-tocopherol were 31, 6 1, and 88 pg/mL, respectively. Also, the protein samples had strong scavenging effect on hydroxyl radical and the values EC50 of FP, FF, SF, Fr-1, and Fr-2 were 48.91, 27.72, 1.82, 16.36, and 160.93 mu g/mL, but values EC50 of Vc and mannitol were 1907 and 4536 mu g/mL, respectively. Of the five protein samples, SF had the strongest radical scavenging activity and may have a use as a possible supplement in the food and pharmaceutical industries. The radical scavenging activity was stable at high temperature so that R. esculentum may be used as a kind of natural functional food. (c) 2005 Elsevier Ltd. All rights reserved.

CHINESE NITRARIA TANGUTORUM BOBR。： CHEMICAL CONSTITUENTS OF SEED OIL EXTRACTED BY SFE-CO_2

In order to develop and make good use of Nitraria tangutorum Bobr. in Qinghai-Tibetan Plateau for its ecological and medicinal values, the seed oil was extracted by SFE-CQ2 and the chemical constituents was analyzed by GC/MS. The component relative contents were determined by area nomalization. 28 components were separated from the extracts of SFE-CQj and 12 of them, which accounted for 85.99% were identified. They were(Z, Z)-9, 12-octadecadienoic acid (linoleic acid), bicyclo[ 10. 1. 0] tridec-1-ene, 7-pentadecyne, gamma-sitosterol, gamma-tocopherol, 1, -8,Z-10-hexadecatriene,9,12-octadecadienal, 24-methyl-5-cholestene-3-ol,(Z)-9,17-octadecadienal, stigmastan-3,5-dien, eicosane and so on. Among them, the relative content of (Z, Z)-9,12-octadecadienoic acid is the highest, accounting for 65.85% of the total area. It is concluded that N. tangutorum Bobr. seed oil is a rich source of linoleic acid.