碱性功能化离子液体在Knoevenagel缩合反应中的应用进展

Knoevenagel缩合反应被广泛应用于合成香豆素、化妆品及药物中间体功能化离子液体的设计、合成为Knoevenagel缩合反应提供了高效、环保的制备途径。以功能化离子液体为催化剂或者溶剂,一系列的醛和酮类化合物与活泼亚甲基化合物的缩合反应可以顺利进行,避免了使用额外的催化剂。文章综述了碱性功能化离子液体在Knoev...     

香豆素类化合物对朱砂叶螨的触杀活性及定量构效关系研究

采用玻片浸渍法,测定并筛选了25种具有代表性的香豆素类化合物对朱砂叶螨Tetranychus cinnabarinus雌成螨的触杀活性,并构建了一个预测能力较强的定量构效关系(QSAR)模型。结果表明:所有供试化合物对朱砂叶螨均具有触杀活性,且随着处理时间的延长活性升高。处理48 h后,LC50值低于1000 mg/L的化合物有8个,分别是3-(2-苯并咪唑)-7-(二乙氨基)香豆素(1)、3-(2-苯并噻唑)-7-(二乙氨基)香豆素(2)、3-氨基香豆素(3)、3-乙酰基香豆素(4)、4-甲氧基香豆素(5)、6-硝基香豆素(8)、6,7-二甲氧基香豆素(13)和7,8-二羟基香豆素(21),其中化合物1、2、3、5和13的杀螨活性优于药剂对照螺螨酯或与其活性相当;活性最好的化合物为13,处理48 h和72 h后LC50值分别为284.8和122.2 mg/L,其毒力约为螺螨酯的2倍。通过计算得到25种香豆素类化合物的34种物化参数,以此为描述子,经过SPSS相关性剔除、逐步回归分析和校正,得到一个以扭转力、取向力、总能量和分子半径为自变量的QSAR模型,该模型复相关系数R达到0.987,复判定系数R2也达到0.967,通过F检验证明上述模型具有较高的预测能力。     

大花金鸡菊叶提取物除草活性的研究

本研究以大花金鸡菊叶为供试材料,于室内采用琼脂混粉法测定了甲醇、乙醇和蒸馏水3种溶剂提取物在0.625g?L-1处理浓度下对夏至草和稗幼苗生长的影响,发现乙醇溶液提取物的抑制活性最高,且不同浓度乙醇提取物的研究表明该溶剂的最佳提取浓度为100%。该浓度乙醇溶液所获得的大花金鸡菊叶提取物在不同处理浓度下对夏至草和稗幼苗的生长均显示了一定的抑制活性,得出有效中浓度（EC50）分别为夏至草胚根/胚轴（0.159g?L-1/0.595g?L-1）和稗种子根/胚芽鞘（0.489g?L-1/3.43g?L-1）。进而用石油醚、乙酸乙酯和正丁醇分别对该浓度乙醇溶液的提取物进行了液液萃取,获得含水相在内的4个萃取相,它们在2g?L-1的处理浓度下对生菜、小麦、夏至草和稗幼苗生长的抑制作用均以石油醚萃取相最高,该结果为进一步开展活性物质的分离及开发植物源除草剂提供了依据。     

Induction of peroxidase, scopoletin, phenolic compounds and resistance in Hevea brasiliensis by elicitin and a novel protein elicitor purified from Phytophthora palmivora

Elicitin and a new protein 75 kDa elicitor were purified from the culture filtrate of Phytophthora palmivora, a pathogen of Hevea brasiliensis (rubber plant). Elicitin was obtained by using a one step of DEAE cellulose chromatography and the new elicitor was obtained by two steps of chromatography: a DEAE cellulose column followed by a hydrophobic column. Both elicitors were stable to heat and a wide range of pH values, but were sensitive to ProteaseK. Both elicitors induced scopoletin, peroxidase isozymes (with substrate o-dianisidine and scopoletin) and total phenolic compounds in cell suspension of H. brasiliensis with similar kinetics. In addition, both elicitors induced peroxidase enzyme (o-dianisidine), total phenolic compounds and enhanced local resistance against P. palmivora on young rubber tree seedlings. However, the increase of peroxidase enzyme and total phenolic compounds in rubber tree seedlings was different from those in cell suspension. Furthermore, during the expression of local resistance the zoospore of P. palmivora induced the peroxidase enzyme (o-dianisidine) more rapidly and with higher level than the control plants. H. brasiliensis is more responsive to the new elicitor than elicitin in triggering defense responses. That is the new elicitor was active at a concentration lower than those required for elicitin, about a 30-fold decrease for activation defense responses in cell suspension. For induction of peroxidase enzyme (o-dianisidine), phenolic compounds and local resistance of rubber plants against P. palmivora, the 75 kDa protein was active at about a 2-fold lower concentration when compared to elicitin.     

Diversity of defence mechanisms in plant–oomycete interactions: a case study of <Emphasis Type="Italic">Lactuca</Emphasis> spp. and <Emphasis Type="Italic">Bremia lactucae</Emphasis>

Plant pathogenic oomycetes, including biotrophic downy mildews and hemibiotrophs/necrotrophs such as Phytophthora and Pythium, cause enormous economic losses on cultivated crops. Lettuce breeders and growers face the threat of Bremia lactucae, the causal agent of lettuce downy mildew. This pathogen damages leaf tissues and lettuce heads and is also frequent on wild Asteraceae plants. The interactions of Lactuca spp. with B. lactucae (abbr. lettuce–Bremia) display extreme variability, due to a long co-evolutionary history. For this reason, during the last 30 years, the lettuce–Bremia pathosystem has been used as a model for many studies at the population, individual, organ, tissue, cellular, physiological and molecular levels, as well as on genetic variability and the genetics of host–parasite interactions. The first part of this review summarizes recent data on host–parasite specificity, host variability, resistance mechanisms and genetics of lettuce–Bremia interactions. The second part focuses on the development infection structures. Phenotypic expression of infection, behaviour of B. lactucae on leaf surfaces, the process of penetration, development of primary infection structures, hyphae and haustoria are discussed in relation to different resistance mechanisms. In the third part, the components of host resistance and the variability of defence responses are analysed. The role of reactive oxygen species (ROS), antioxidant enzymes, nitric oxide (NO), phenolic compounds, reorganization of cytoskeleton, electrolyte leakage, membrane damage, cell wall disruption, hypersensitive reaction and plant energetics are discussed in relation to defence responses. In general, the extreme variability of interactions between lettuce and Bremia, and their phenotypic expression, results from diversity of the genetic background. Different mechanisms of resistance are conditioned by an orchestra of defence responses at the tissue, cell, and molecular levels. The various events responsible for defence involve a complex interaction of the processes and reactions mentioned above. This review also provides an overview on the timing of pathogen development, host pathological anatomy, cytology and physiology of lettuce–Bremia associations. The significance of these factors on the expression of different resistance mechanisms (non-host and host resistance, race-specific and race non-specific resistance, field resistance) is discussed.     

Allelopathic effect of the root exudates of K21, a potent allelopathic rice

An inhibitory effect of the phenolic compounds released from the roots of K21, a newly bred potent allelopathic rice, was investigated in comparison to its male parent, Kouketsumochi, and its female parent, Dongjinbyeo. The inhibitory rates of the root exudates of K21 and both of its parents, collected at 5 day intervals, on the shoot growth of Echinochloa crus-galli var. praticola exhibited an increasing trend from 19–34 days after seeding (DAS). However, the root exudates of K21, at concentrations of 0.5, 1.0, and 2.0%, showed a greater inhibitory effect than those of its female parent on the growth of E. crus-galli var. praticola at the earlier collection dates. Nine phenolic compounds were identified; the total amount of phenolic compounds in the exudates increased from 19–34 DAS in both K21 and its male parent, but not much in the female parent. The subsequent increase in the amount of total phenolic compounds in the root exudates of the later investigation dates and the trend of increasing inhibitory rates on the shoot growth of E. crus-galli var. praticola at higher exudate concentrations imply that the increased amount of phenolic acids in the root exudates of K21 secreted on the subsequent dates could be related to its greater allelopathic effects.     

Synthesis of a new thiophosphorylated compound derived from cashew nut shell liquid and study of its antioxidant activity

This work describes the synthesis and study of the antioxidant activity in mineral oils of new thiophosphorylated compound derived from cashew nut shell liquid (CNSL), a by-product of the process of improvement of cashew nuts. This study was conducted through the thermal analysis observing the T_onset variations and the accelerated oxidation experiments observing the induction time variations. The results of thermogravimetric and acceleration oxidative experiments showed a significant improvement in the oxidative stability of the doped oils. These results suggest that this new compound acts efficiently in the stabilization of the naphthenic mineral oils.     

柴油机燃用乙醇—生物柴油—柴油的醛酮类排放物研究

利用高效液相色谱仪对柴油机燃用普通柴油(D)和乙醇-生物柴油-柴油(EBD)排放物中的醛酮类化合物进行比较分析。研究结果表明:标定转速,10%和50%负荷下,EBD总排放量比D分别降低了2.98%和16.42%,全负荷下,升高了11.79%;排放物以甲醛、乙醛、丙烯醛和丙酮等C1～C3污染物为主,占醛酮排放物91.9%以上;负荷增加或转速降低,醛酮类排放物减少。     

不同生育期美丽风毛菊PSⅡ光化学效率和色素含量对UV-B辐射的响应

以高山植物美丽风毛菊为材料,在矮嵩草草甸植物群落生长季的不同月份,采用短期滤除太阳辐射光谱中UV-B成分的方法,研究了UV-B辐射对PSⅡ光化学效率、光合色素和紫外吸收物质的影响。结果表明,1)与对照相比,low UV-B处理时3 min暗适应的PSⅡ最大光化学量子效率F_v/F_m呈升高的趋势,说明UV-B辐射能加剧PSⅡ反应中心的可逆失活或损伤程度。2)PSⅡ实际光化学效率Φ_PSⅡ和光化学猝灭系数qP在生长季内具有基本一致的变化趋势;low UV-B处理能引起Φ_PSⅡ和qP的升高和NPQ的降低,表明自然光谱中的UV-B成分能降低叶片的光能捕获效率,促进非光化学能量耗散过程。3)low UV-B处理时光合色素的降低与叶片变薄有关,强太阳UV-B辐射下光合色素的相对增加是一种表象。综上可知,青藏高原强太阳UV-B辐射对高山植物的光合生理过程具有潜在的负影响,叶片中高含量且相对稳定的UV-B吸收物质可有效屏蔽太阳UV-B光量子抵达光合机构等敏感部位,不同生育期叶片PSⅡ光化学效率的差异与环境因子和叶片发育状态有关。     

微波辅助提取鸡屎藤茎挥发油及其成分分析

[目的]研究微波辅助环己烷提取鸡屎藤茎挥发油的最佳提取工艺条件,通过气质联用（GC-MS）技术分析挥发油成分及含量,为科学利用鸡屎藤提供参考。[方法]用微波辅助环己烷提取鸡屎藤茎挥发油,并用GC-MS对其挥发油成分进行分析,利用正交试验筛选挥发油提取的最佳工艺条件。[结果]微波辅助环己烷提取鸡屎藤茎挥发油的最佳提取工艺为M鸡屎藤茎∶V环己烷=2∶60（g/ml）,微波提取10min,微波功率800 W,微波温度50℃,挥发油收率可达1.32%。通过GC-MS技术从微波辅助提取的鸡屎藤茎提取物中共检测出10种组分,鉴定出7种化合物,占总峰面积的90.690%,提取物中主要成分为n-棕榈酸（18.424%）、邻苯二甲酸异丁基壬酯（24.243%）和油酸（15.131%）。[结论]微波辅助环己烷提取鸡屎藤茎挥发油提取速率快,出油率高,但是分离鉴定出的组分太少,有待进一步完善。