基于微量筛选模型的48种中草药提取物乙酰胆碱酯酶抑制活性筛选及评价

采用微量筛选模型考察48种中药提取物的乙酰胆碱酯酶抑制活性。采用不同极性溶剂对中药材进行提取,采用微量筛选模型对不同浓度提取物的乙酰胆碱酯酶抑制活性进行考察,并采用Origin8.0计算其IC50值。结果表明,几种中药材的不同极性溶剂(水、80%乙醇、乙酸乙酯、石油醚)提取物有不同程度的乙酰胆碱酯酶抑制活性。其中黄柏、元胡的80%乙醇提取物,丹参的乙酸乙酯提取物的抑制率较高。当上述提取物在实验体系中的终浓度为76.92 mg/L时,抑制率分别为66.72±0.02%、52.67±0.04%、46.84±0.03%,其IC50值分别为295.12、229.09、1202.26 mg/L。本研究结果为从中草药中快速筛选乙酰胆碱酯酶抑制剂提供了方法和数据支持。     

不同蕨类植物提取物乙酰胆碱酯酶抑制活性的评价

为对采自浙江天目山的40种蕨类植物乙醇提取物进行乙酰胆碱酯酶抑制活性研究。本文采用乙酰胆碱酯酶抑制活性筛选模型。结果表明：在供试质量浓度在1mg／mL时,40种植物的乙醇提取物均具有明显的乙酰胆碱酯酶抑制活性,其中密羽贯众、野雉尾金粉蕨和狗脊等13种蕨类植物表现出较强的抑制活性,抑制率均大于90％,其余大部分植物的抑制率均大于60％。而在供试质量浓度在0．025mg／mL时,只有少数植物表现出较高的乙酰胆碱酯酶抑制活性,其中狭顶鳞毛蕨的抑制率为62．63％±3．72％,蜈松草的抑制率为48．01％±2．87％,其余大部分植物的抑制活性均小于40％,甚至有些植物提取物不仅对乙酰胆碱酯酶没有抑制活性,反而表现出一定的增强作用。     

β-细辛醚对谷蠹成虫体内四种酶活性的影响

采用石菖蒲Acorus gramineus根茎提取物β-细辛醚对谷蠹Rhizopertha dominica成虫进行拌粮处理,测定β-细辛醚对谷蠹体内乙酰胆碱酯酶、谷胱甘肽S-转移酶、羧酸酯酶和酯酶同工酶的时间效应和剂量效应。结果表明：β-细辛醚对试虫体内4种酶的酶活性均表现出较强的时间效应。LC₅₀（94.49 mg/kg）剂量的β-细辛醚处理后,谷蠹成虫体内乙酰胆碱酯酶和谷胱甘肽S-转移酶活性随处理时间的延长整体表现为抑制作用,对羧酸酯酶和酯酶同工酶则表现诱导增加作用。低剂量（67.5 mg/kg）β-细辛醚对乙酰胆碱酯酶具有显著的诱导作用,但是随着处理剂量的升高,对乙酰胆碱酯酶的活力多数表现为抑制作用。低剂量（≤100.0 mg/kg）β-细辛醚对谷胱甘肽S 转移酶具有诱导作用,而高剂量（≥133.3 mg/kg）β-细辛醚对谷胱甘肽S-转移酶具有抑制作用。β-细辛醚对羧酸酯酶的活性多数表现为诱导作用,提高β-细辛醚的处理剂量可提高羧酸酯酶的活力。不同剂量的β-细辛醚处理对谷蠹酯酶同工酶均具有显著的诱导作用,但诱导效果与处理剂量关系并不显著。     

繁殖寄主对赤眼蜂羧酸酯酶和乙酰胆碱酯酶的影响

通过测定赤眼蜂Trichogramma羧酸酯酶和乙酰胆碱酯酶的活性、对底物的亲和力以及对抑制剂的敏感度研究了繁殖寄主对松毛虫赤眼蜂T.dendrolimi和螟黄赤眼蜂T.chilonis的影响。柞蚕卵和米蛾卵繁殖的赤眼蜂羧酸酯酶对底物的亲和力有不同程度的影响,柞蚕卵繁殖的赤眼蜂羧酸酯酶对α-乙酸萘酯或β-乙酸萘酯的亲和力最高是米蛾卵的2倍以上。繁殖寄主对乙酰胆碱酯酶对底物亲和力没有明显的影响。米蛾卵繁殖的松毛虫赤眼蜂羧酸酯酶活性明显高于柞蚕卵繁殖的种群,而米蛾卵繁殖的螟黄赤眼蜂种群羧酸酯酶的活性明显低于柞蚕卵繁殖的种群。用柞蚕卵繁殖的松毛虫赤眼蜂种群对对氧磷的敏感度明显低于米蛾卵繁殖的种群,而增效磷则正好相反。繁殖寄主对松毛虫赤眼蜂吉林种群乙酰胆碱酯酶对DDVP和毒扁豆碱的敏感度没有明显的影响,而在松毛虫赤眼蜂广东种群和螟黄赤眼蜂中,柞蚕卵繁殖的种群乙酰胆碱酯酶对DDVP和毒扁豆碱的敏感度明显低于米蛾卵繁殖的种群。     

抗胆碱酯酶剂亚致死剂量对棉铃虫毒力的影响及对乙酰胆碱酯酶的诱导作用

辛硫磷、马拉硫磷和灭多威3种抗胆碱酯酶剂亚致死剂量（LD10）预处理棉铃虫Helicoverpa armigera 3龄幼虫24 h后,对辛硫磷、马拉硫磷、灭多威、溴氰菊酯和高效氯氰菊酯5种杀虫药剂的毒力影响有明显差异。酶动力学研究表明：在48 h内,辛硫磷亚致死剂量对棉铃虫乙酰胆碱酯酶比活力有一定的抑制作用,24 h仅为对照组的0.56倍;马拉硫磷、灭多威则可以诱导乙酰胆碱酯酶的比活力增加,诱导最大值时间分别为3 h和12 h。通过对米氏常数（K_m）值分析表明,辛硫磷诱导48 h内对乙酰胆碱酯酶与底物亲和力的影响不大,马拉硫磷、灭多威诱导48 h内乙酰胆碱酯酶对底物亲和力有所下降,其中灭多威诱导组最为明显。3种药剂亚致死剂量处理24 h后,通过蔗糖密度梯度离心表明5%蔗糖梯度层乙酰胆碱酯酶分布百分数明显高于对照组,而20%蔗糖梯度层却明显低于对照组,说明亚致死剂量处理可能引起乙酰胆碱酯酶分子型及不同分子型分布比例的变化。     

马拉硫磷和敌百虫混用和轮用的研究:淡色库蚊的酯酶同功酶与抗性的关系

用马拉硫磷和敌百虫单独处理30代和31代的淡色库蚊,见到对马拉硫磷和敌百虫的抗性分别为敏感品系的286和303倍,而以马拉硫磷和敌百虫轮用(32代)和混用(31代)处理的品系对马拉硫磷和敌百虫的抗性均在70倍以下。 离体酶的活性测定和酯酶同功酶的酶谱分析均表明,抗性品系体内羧酸酯酶活力高于敏感品系;酸性磷酸酯酶和乙酰胆碱酯酶的活力两者差异不显著,可见马拉硫磷和敌百虫的抗性主要和羧酸酯酶活力的增长有关。     

甜菜夜蛾体内代谢耐受性对转Bt基因棉响应的时间动态

在室内用转Bt基因棉和亲本常规棉饲养甜菜夜蛾（Spodoptera exigua Hübner）幼虫,测定了不同取食时间后甜菜夜蛾4龄幼虫体内营养物质含量和消化酶、保护酶、解毒酶活力的变化．结果表明,分别取食Bt棉和常规棉,甜菜夜蛾幼虫体内的营养物质含量和消化酶、保护酶、解毒酶活力差异显著．与取食常规棉相应时间的个体相比,取食Bt棉1,6,24h后,幼虫体内的游离脂肪酸和葡萄糖含量显著提高;取食Bt棉1,4,6,24h后,幼虫体内胰蛋白酶和总超氧化物歧化酶的活力显著增高,脂肪酶、羧酸酯酶和乙酰胆碱酯酶活力则显著降低．取食相同品种棉花,幼虫体内营养物质含量和消化酶、保护酶、解毒酶活力受甜菜夜蛾危害时间的显著影响．取食Bt棉24h的幼虫,其体内游离脂肪酸和总氨基酸含量显著低于取食1h的个体;脂肪酶和胰蛋白酶活力显著低于取食1和4h的个体,但羧酸酯酶和乙酰胆碱酯酶酶活力显著高于取食1,4,6h的个体．棉花品种和甜菜夜蛾为害时间的交互作用可显著影响甜菜夜蛾体内脂肪酶、胰蛋白酶、乙酰胆碱酯酶和总超氧化物歧化酶的活力．通过测定甜菜夜蛾体内保护酶和解毒酶活力对Bt棉响应的时间动态,对于评价植食性昆虫在毒素蛋白持续选择压力下的生理反应和抗性变化具有重要参考意义．     

苏云金杆菌预处理小菜蛾对有机磷和氨基甲酸酯杀虫剂的增效作用

研究了小菜蛾Plutella xylostella幼虫经苏云金杆菌Bacillus thuringiensis预处理后,对有机磷和氨基甲酸酯杀虫剂敏感性的变化以及预处理对小菜蛾幼虫体内乙酰胆碱酯酶、羧酸酯酶、谷胱甘肽S-转移酶和谷胱甘肽的含量的影响。结果表明：苏云金杆菌预处理抗性小菜蛾幼虫后,其对甲胺磷、水胺硫磷和克百威的敏感性分别为未处理组的6.74、8.83和8.50倍;处理敏感小菜蛾幼虫后则分别为未处理组的2.96、1.69和3.88倍。苏云金杆菌预处理抗性小菜蛾,未处理组乙酰胆碱酯酶的K_m和V_max值分别为预处理组的1.86和1.56倍,所使用的6种杀虫剂对乙酰胆碱酯酶的K_I值,处理组为未处理组的1.80～2.66倍,苏云金杆菌预处理抗性小菜蛾对羧酸酯酶的K_m、K_I影响不大,但能显著地抑制羧酸酯酶和谷胱甘肽S-转移酶的活性并导致谷胱甘肽含量下降(对照分别为处理的2.02、1.76和1.66倍)。苏云金杆菌预处理敏感小菜蛾,对乙酰胆碱酯酶的K_m、V_max、K_I值和羧酸酯酶的K_m、K_I值以及谷胱甘肽含量影响不大,但能显著地抑制羧酸酯酶和谷胱甘肽S-转移酶的活性(对照分别为处理的1.54和1.64倍)。     

井冈山区63种植物不同溶剂萃取物乙酰胆碱酯酶抑制活性的初步研究

采用乙酰胆碱酯酶(AChE)抑制活性筛选模型,对采自井冈山及周边地区的63种植物(67个部位)乙醇提取物的不同溶剂萃取物进行AChE抑制活性研究。结果表明:在乙酸乙酯萃取物中,供试质量浓度在1 mg/mL时,其中剪刀草和戟叶蓼表现出较强的AChE抑制活性,抑制率均大于90%,其余大部分植物均大于40%。供试质量浓度在0.025 mg/mL时,蛇莓等6种植物的抑制率大于60%,其余大部分植物小于30%;在正丁醇萃取物中,供试质量浓度在1 mg/mL时,紫萼变种、活血丹、菟丝子、剪刀草、冬青叶山茶叶、地念和车前草的抑制率大于80%,其余大部分植物的抑制率均大于40%。供试质量浓度在0.025 mg/mL时,秀丽四照花等22种植物抑制率均大于50%;在石油醚萃取物中,供试质量浓度在1 mg/mL时,紫萼变种、紫茎前胡、博落回、杠板归、地念、山橿、藤石松和车前草的抑制率大于90%,供试质量浓度在0.025 mg/mL时,紫茎前胡等17种植物抑制率大于70%。另外,有些植物萃取物不仅对AChE没有抑制活性,反而表现出一定的增强作用。     

家蝇中乙酰胆碱酯酶、羧酸酯酶和多功能氧化酶活性与抗药性的关系

本文对几种抗药性和敏感性家蝇品系的乙酰胆碱酯酶(AChE)、羧酸酯酶及多功能氧化酶(MFO)进行了测定.结果表明:①抗药性品系和敏感性品系的AChE活力差异不大, 有机磷抗性品系的AChE对对氧磷的不敏感性比敏感性家蝇明显增大.②某些抗药性家蝇的羧酸酯酶活力比敏感性家蝇大.③抗药性家蝇的MFO活力(O-脱甲基和环氧化)比敏感性家蝇均有不同程度的增高.④二氯苯醚菊酯抗性家蝇对有机磷有负交互抗性.     

Palynology and palynofacies of Miocene coal-bearing (clastic) sediments of the Hausruck area (Austria)

Two drill cores with coal-bearing sediments from the localities Lukasberg and Kalletsberg of the Hausruck area were investigated. Particular attention was paid to the clastic intercalations between and within the coal seams to complete the previous database of the coal-petrological and geochemical analyses of the coals made by Gruber and Sachsenhofer (1999) and Bechtel et al. (2003). In this work, pollen and spores, the acid-resistant organic components (palynofacies), and the total organic carbon content (TOC) of the clastic sediments have been examined in order to interpret the palaecological conditions of the different plant habitats. The TOC and structured components of the Lukasberg site displayed a recurring cyclicity between coal seams and are interpreted as frequent changes of the depositional environment: coal swamps and peat bogs, lacustrine conditions (lake or pond) and marshes or clastic swamps. It is therefore assumed that the Hausruck area, particularly at the Lukasberg locality, was subjected to periodical submersions, in which the ground-water level repeatedly flooded the coal swamps. This cyclicity is unfortunately not clearly documented at the Kalletsberg locality. In addition, the occurrence of up to 32% fusinite in the palynofacies from some samples of both sites and charred logs at the Lukasberg open cast mine indicate the presence of palaeo-wildfires within forests of the Hausruck area. The age of the sedimentary succession is late Sarmatian to the early/middle Pannonian (upper Middle Miocene to lower Upper Miocene). The frequent occurrences of pollen of Mastixia, a warmth loving plant, which during this time interval occurred sporadically and in low numbers, suggest that the Hausruck was a relict area with a particular humid and warm climate.     

Effects of leachates of the invasive plant, Ageratina adenophora (Sprengel) on soil microbial community

The invasive plant Ageratina adenophora (Sprengel) changed soil microbial communities in the invaded area to facilitate its growth and inhibit native plants. However, little is known about the driving forces underlying the alteration of soil biota. Leachates from root and aerial part (stem and leaves) of A. adenophora were mixed into soil to imitate field invasion processes for evaluation of its impact on invasion of soil microbial community. The results indicated that soil microbial community was significantly changed when the soil taken from the newly-invaded area was treated with A. adenophora root and aerial part leachates for 3 and 5 weeks, respectively. The biota of newly invaded soil treated with concentration of 100 mg/mL A.adenophora leachates was much closer to that of heavily invaded soil, but was significantly different from that of control soil (newly invaded soil without treatment). A.adenophora leachates promoted growth of the seven dominant rhizosphere bacterial species in the invaded soil. The effect of A.adenophora leachates on soil biota and dominant rhizosphere bacteria was positively correlated with the concentration of leachates, however, the effect of root leachates was stronger than the aerial part leachates. It is assumed that A.adenophora change soil microbial community via nutritional and chemical communication, which helps it in better colonization of the invaded soil.     

Competition effects on wiregrass (Aristida beyrichana) growth and survival

We investigated neighboring plant effects (competition and facilitation)on wiregrass establishment in two frequently encountered restoration situationsof former longleaf pine-wiregrass habitats in the Southeastern United States:longleaf pine plantations and previously cultivated fields. In the plantationexperiment, we specifically examined canopy removal, neighboring wiregrassdensity, and aboveground and belowground effects on establishment and growth ofwiregrass seedlings at two different ages (3 weeks and 6 months) with 3competitive exclusion treatments (aboveground exclusion, belowground exclusion,or no exclusion). Competition treatment effects were age-dependent forsurvivorship and growth. Survival of 6 month old seedlings was unaffected bycompetition treatment; whereas, three week old seedling survival was greatestwhere roots were excluded. Seedling size increased with root exclusion for 6month seedlings, but not for 3 week old seedlings in plots lacking neighboringwiregrass. Where wiregrass was present, both 3 week and 6 month old seedlingsincreased growth with root exclusion. Furthermore, where neighboring wiregrassplants were absent, increasing canopy density resulted in decreased seedlingsize, but did not affect survivorship. In old fields, fertilizer treatments andweeding effects were also assessed using 3 week and 6 month old seedlings.Fertilizer application did not benefit seedling survival or growth and reducedsurvivorship of 3 week old seedlings. Seedlings were smaller where neighboringold field, weedy vegetation was present regardless of wiregrass seedling age;whereas, survival was dependent on seedling age at time of planting. Six monthold seedling survivorship remained high regardless of weeding treatment. It isstill unclear whether fertilizer application is beneficial to the successfulestablishment of wiregrass.     

Effects of leachates of the invasive plant, Ageratina adenophora (Sprengel) on soil microbial community

The invasive plant Ageratina adenophora (Sprengel) changed soil microbial communities in the invaded area to facilitate its growth and inhibit native plants. However, little is known about the driving forces underlying the alteration of soil biota. Leachates from root and aerial part (stem and leaves) of A. adenophora were mixed into soil to imitate field invasion processes for evaluation of its impact on invasion of soil microbial community. The results indicated that soil microbial community was significantly changed when the soil taken from the newly-invaded area was treated with A. adenophora root and aerial part leachates for 3 and 5 weeks, respectively. The biota of newly invaded soil treated with concentration of 100 mg/mL A.adenophora leachates was much closer to that of heavily invaded soil, but was significantly different from that of control soil (newly invaded soil without treatment). A.adenophora leachates promoted growth of the seven dominant rhizosphere bacterial species in the invaded soil. The effect of A.adenophora leachates on soil biota and dominant rhizosphere bacteria was positively correlated with the concentration of leachates, however, the effect of root leachates was stronger than the aerial part leachates. It is assumed that A.adenophora change soil microbial community via nutritional and chemical communication, which helps it in better colonization of the invaded soil.     

The Effectiveness of Trichogramma chilonis,Trichogramma pretiosum and Trichogramma brasiliense (Hymenoptera: Trichogrammatidae) as Parasitoids of Helicoverpa armigera (Lepidoptera: Noctuidae) on Sunflower (Helianthus annuus) and Redgram (Cajanus cajan)

The performance of three species of trichogrammatids on the pest, Helicoverpa armigera was evaluated in the laboratory and screenhouse conditions in Karnataka, India during 1996-97. Laboratory studies indicated that Trichogramma chilonis and Trichogramma pretiosum were more effective parasitoids of H. armigera than Trichogramma brasiliense. In screenhouse conditions, T. chilonis was the most effective parasitoid of H. armigera eggs on sunflower plants in comparison to the other two trichogrammatid species. When releasing 50?000 per ha on sunflower and redgram, T. chilonis parasitised 50.1 and 11.4% H. armigera eggs, respectively. The position of H. armigera eggs on different plant parts of sunflower had no effect on parasitism by T. chilonis. However, parasitism by the same trichogrammatid among different plant parts of redgram varied significantly. It parasitized 43.4 and 18.7% H. armigera eggs on leaves and flowers, respectively, and significantly fewer, 3.9%, on pods (P<0.05). The growth stage of redgram plants also had an effect on parasitism by T. chilonis, parasitism being extremely low on plants with pods.     

三种植物粉剂对四纹豆象(鞘翅目:豆象科)行为、死亡率和繁殖的影响

The effects of powders from dry flower buds of Eugenia aromatica Baill., seeds of Piper guineense Schum and Thonn and fruits of Capsicum frutescens L. on adult behaviour, mortality and reproductive fitness of the cowpea seed beetle, Callosobruchus maculatus （Fab.） were investigated under ambient laboratory conditions. All experiments were carried out in glass Petri plates. All powders elicited aversion in adult beetles. The contact toxicity symptoms included restlessness, loss of coordination, knock down and eventual death of adult beetles. These behaviours were more pronounced with E. aromatica in which adult beetles died within 16 hours. P. guineense and C. frutescens powders did not cause 100% mortality of adult beetles, even after 24 hours. Each of the three powders significantly （P 〈 0.05） reduced the mating competition of adult males after sub-lethal exposure for one, two, and three hours, respectively. E. aromatica powder caused more reduction in male mating competition for females than any of the other two powders after each period of exposure. Receptiveness of treated females to courting males was also decreased by exposure to any of the three powders. Similarly, E. aromatica powder caused greater decreases in female receptiveness to males than any of the other two powders after each period of exposure. Exposure of either adult male or female C. maculatus to the powders for sub-lethal times of three, six and nine hours significantly reduced the fecundity of the beetles. E. aromatica powder caused the most reduction of eggs laid and also significantly reduced fertility of the eggs.     

Disturbance and demography of Phylica arborea (Rhamnaceae) on the Tristan-Gough group of islands

Populations of Phylica arborea Thouars, an evergreen tree endemic to six southern oceanic islands, have been depleted by wood gathering and browsing on Amsterdam Island and Tristan da Cunha, and it was feared that introduced rodents were destroying seed and reducing regeneration on uninhabited Gough Island. A comparison of the demography of this species on four islands in the Tristan-Gough group suggests that rodents have little effect on seedling numberS. Regeneration seldom occurs in undisturbed P. Arborea groves: germination and seedling survival appears to be dependent on periodical removal of established trees and understorey vegetation by soil-slips and occasional fireS. Climatic and vegetation differences problably account for the less frequent regeneration at Gough Island relative to that at the Tristan islands.     

Shedding light on plant competition: modelling the influence of plant morphology on light capture (and vice versa)

A plant's morphology is both strongly influenced by local light availability and, simultaneously, strongly influences this local light availability. This reciprocal relationship is complex, but lies at the heart of understanding plant growth and competition. Here, we develop a sub-individual-based simulation model, cast at the level of interacting plant components. The model explicitly simulates growth, development and competition for light at the level of leaves, branches, etc., located in 3D space. In this way, we are able to explore the manner in which the low-level processes governing plant growth and development give rise to individual-, cohort-, and community-level phenomena. In particular, we show that individual-level trade-offs between growing up and growing out arise naturally in the model, and robustly give rise to cohort-level phenomena such as self-thinning, and community processes such as the effect of ecological disturbance on the maintenance of biodiversity. We conclude with a note on our methodology and how to interpret the results of simulation models such as this one.     

植物类过敏性蛋白(变应原)研究进展

据相关资料最新统计表明,全球大约有25%的人口受到I型变态反应疾病的影响。植物中的花粉、汁液和果实可以分别作为吸入性、接触性和食入性过敏原影响过敏体质的人群。目前,惟一有效的办法是应用特异性变应原进行脱敏治疗(脱敏治疗)。而在应用天然变应原提取物进行传统免疫治疗过程中存在一定的危险性。通过基因工程的方法合成的修饰后的高纯度特异变应原在保持过敏性蛋白完整的免疫活性的同时可降低其本身的过敏原性。这种修饰后的过敏性蛋白的应用将使免疫治疗更趋于标准化操作同时避免应用天然过敏性蛋白天然提取物时的危险性,最终可达到提高治疗的效果的目的。目前,重组这种新的过敏性蛋白已经成为过敏性疾病研究的新的热点。