C12-水解印楝素A的制备、结构鉴定及生物活性

C12-水解印楝素A是将印楝素A C12位上的-COOCH3水解为-COOH而得到的印楝素衍生物。处理后24h和48h,C12-水解印楝素A对斜纹夜蛾3龄幼虫AFC50分别为3．44μg／mL和6．89μg／mL。处理后48h,3μg／mL C12-水解印楝素A对小菜蛾3龄幼虫的拒食率为73．59％,5μg／mL C12-水解印楝素A对棉铃虫3龄幼虫的拒食率为67．76％。3μg／mL C12-水解印楝素A处理后72h,小菜蛾3龄幼虫的校正死亡率为78．16％;5μg／mL C12-水解印楝素A处理后72h,棉铃虫3龄幼虫的校正死亡率为58．69％。     

印楝素A与印楝素B对粉纹夜蛾BTI-Tn-5B1-4的细胞毒性

为了明确印楝素A和B活性差异的机理,本研究比较了印楝素A和印楝素B对粉纹夜蛾Trichoplusia ni离体培养胚胎细胞系BTI-Tn-5B1-4的毒性。结果表明：印楝素A与印楝素B对BTI-Tn-5B1-4细胞具有良好的增殖抑制活性,处理后3 d,其IC₅₀值分别为2.9 μg/mL和9.85 μg/mL,印楝素A的细胞毒力显著高于印楝素B。倒置显微镜观察发现,印楝素A和印楝素B处理可导致细胞变形,贴壁能力下降,并出现明显空泡,印楝素A的影响明显高于印楝素B。流式细胞仪检测结果表明,印楝素可导致BTI-Tn-5B1-4细胞体积显著膨大,印楝素A处理细胞体积增大程度显著高于印楝素B;印楝素可以明显影响BTI-Tn-5B1-4细胞膜电位,1.25 μg/mL印楝素A和印楝素B处理后3 d,细胞DiBAC4（3）荧光强度分别增加88.12%和55.37%,印楝素A的影响显著高于印楝素B。荧光显微镜观察发现,印楝素对BTI-Tn-5B1-4细胞核具有明显影响,印楝素B的影响明显高于印楝素A,印楝素B处理后,细胞核受损细胞数更多,受损程度更严重。结果显示印楝素A和印楝素B的细胞作用机理存在差异,本研究从细胞学水平解释了印楝素的生长发育抑制作用机理。     

印楝素A对粉纹夜蛾Hi-5细胞的毒性机理

利用粉纹夜蛾Trichoplusia ni Hübner卵细胞系（Hi-5细胞系）在细胞水平研究了印楝素(azadirachtin) A杀卵活性的毒性机理。以MTT法研究了印楝素A对粉纹夜蛾Hi-5细胞的生长抑制率,结果表明最初两天印楝素 A对Hi-5细胞无较明显活性,但随后几天抑制率显著增加。用Giemsa染色法对细胞进行染色,观察细胞形态发生的变化,发现：1.25 μg/mL印楝素 A处理Hi-5细胞1 d后,细胞已无法贴壁,形状变圆,接着细胞形态变得极不规则,有凋亡小体出现。用Ho33342染料对Hi-5细胞核DNA染色,通过荧光显微镜观察发现：经印楝素A处理后第1天,部分细胞核染色体发生异常凝聚,此后异常细胞核比例增多,核膜严重破损。以异硫氰酸荧光素(FITC)荧光染料研究了Hi-5细胞的蛋白质含量变化,发现1.25 μg/mL印楝素A 处理Hi-5细胞1 d后,细胞蛋白质指数(DI)为1.070±0.018,至第3 d DI值上升到1.912±0.019。分析了印楝素A处理后Hi-5的还原性谷胱甘肽(GSH)的相对含量变化,发现1.25 μg/mL处理浓度下,各天处理组GSH抑制率有显著差异。结果显示印楝素A能够抑制Hi-5细胞增殖,影响细胞骨架正常功能,降低细胞活力。     

印楝愈伤组织形成及其印楝素含量测定

取印楝（AzadirachtaindicaA．Juss）不同器官作外植体,研究培养基和继代次数对愈伤组织生长及其印楝素（Azadirachtin）生物合成的影响．印楝的不同器官（根、叶、茎及皮）均能诱导出愈伤组织,这些愈伤组织均有合成印楝素的能力．其中以叶诱导的愈伤组织生长速率及印楝素含量为最高．含有较低按盐的B5培养基有利于细胞生长,含有较高铵盐的MS培养基有利于印楝素积累,不含铰盐的White培养基对两者均不利．愈伤组织继代2—3代,有利于愈伤组织生长和印楝素合成。     

印楝素A和印楝素B对棉铃虫生长发育的影响

为了明确印楝素A和印楝素B生物活性的差异,选用印楝素A和印楝素B对棉铃虫生长发育的影响进行了比较研究。结果表明:印楝素A和印楝素B对棉铃虫3龄幼虫具有良好的拒食活性,5μg/mL处理48 h对棉铃虫3龄幼虫的拒食率分别为85.17%和69.02%。分别用含有药剂(1μg/mL)的饲料饲喂棉铃虫5龄幼虫,结果表明:印楝素A和印楝素B能够明显抑制棉铃虫5龄幼虫的体重增长,处理14 d后幼虫的体重分别下降50.28%和43.08%,仅有少量个体化蛹,化蛹率分别为26.67%和13.33%。进一步的羽化结果表明:经印楝素A和印楝素B处理的虫蛹均未能完成羽化。综合各阶段试验结果来看,印楝素A和印楝素B的生物活性存在差异,印楝素B对棉铃虫生长发育的抑制作用高于印楝素A。     

元谋干热河谷实生印楝人工林产量和品质与叶片养分含量之间的关系

应用临界值浓度法、DRIS图解法和指数法等叶片营养诊断分析方法,研究了元谋干热河谷地区的实生印楝人工林产量和品质与叶片养分含量之间的关系.结果表明:6月份所采集的印楝叶片其养分含量与印楝产量之间存在显著线性相关;获得印楝高产的叶片全N、全P和全K的临界值分别为15.09、1.22和7.68 g·kg-1,相应的最适范围分别为15.09 ～ 22.68、1.22～1.59和7.68 ～9.17 g·kg-1;低产印楝人工林的叶片养分的DRIS图解法和DRIS指数法诊断结果基本一致,它们对N、P、K的需求次序均为P＞N＞K,并且这一结果与当地土壤本底肥分检测结果相印证.此外,叶片养分含量与印楝素含量之间不存在相关性,可能与印楝素本身的遗传因素有关,故不能在印楝实生群体中采用叶片营养诊断技术来进行种仁印楝素含量的诊断分析.     

印楝素乳油对小菜蛾种群的控制作用

通过室内外系统试验探讨了印楝素乳油对小菜蛾Plutella xylostella种群的控制作用。结果表明,其控制作用主要表现在对成虫产卵的显忌避作用。对幼虫的拒食作用以及对生长发育的影响和减少幼虫危害为等方面,印楝素乳油0.005mL/59.0%,使小菜蛾种群趋势指数（I值）降为2.4干扰作用控制指数（IIPC）为0.1079,采用状态空间分析法就印楝素乳油施用后小菜蛾种群数量动态的模拟分析亦表明,其显的控制作用表现在种群发展初期对成虫的忌避作用。     

印楝素乳油对荔枝蒂蛀虫种群的控制作用

利用生命表的方法和干扰作用控制指数评价了印楝素乳油对荔枝蒂蛀虫Conopomorpha sinensisBradley种群的控制作用,结果表明:0.3%印楝素乳油对荔枝蒂蛀虫成虫显著的产卵忌避作用是其对该种群控制的主要机理。在室内,0.3%印楝素乳油在6 mL/L和3 mL/L的浓度处理下,对荔枝蒂蛀虫成虫产卵的忌避率分别为89.3%和86.3%。田间的试验结果表明,在印楝素乳油浓度为6 mL/L和和3 mL/L的处理区中,荔枝蒂蛀虫的种群趋势指数分别为1.23和1.45,显著低于对照区的种群趋势指数11.60,干扰作用控制指数分别为0.106和0.112。这2个浓度的印楝素乳油对荔枝蒂蛀虫种群的控制效果分别可达89.4%和87.5%。     

印楝素农药与虫生真菌混用防治红树林鳞翅目害虫

采用2种印楝素农药1%印楝素苦参碱乳油和0.3%印楝素乳油,以及2个虫生真菌绿僵菌菌株和白僵菌菌株对桐花长卷蛾、棉古毒蛾和广州小斑螟等3种红树林叶面和种子害虫的室内毒力测定结果表明,两种印楝素农药的单剂(500～1000倍)和与虫生真菌的复配剂(700倍),均对害虫有较强的毒性,一周内害虫死亡率达78.6～100%.两种印楝素农药与虫生真菌混合使用均比各自单独使用的杀虫效果好,其中与虫生真菌的复配剂700倍液的杀虫最快,效果最好,第3天柑橘长卷蛾和广州小斑螟的死亡率达100%,棉古毒蛾的死亡率达93.3%.应用1%印楝素苦参碱乳油和0.3%印楝素乳油与绿僵菌和白僵菌的复配剂500倍液进行林间防治危害桐花树的柑橘长卷蛾的试验,防治效果达65.4%～100%,该复配剂具有内吸传导作用、高效、低毒和安全等优点,值得大力推广应用.     

印楝素乳油x对-小菜蛾种群的控制作用

通过室内外系统试验探讨了印楝素乳油对小菜蛾Plutella xylostella种群的控制作用.结果表明,其控制作用主要表现在对成虫产卵的显著忌避作用、对幼虫的拒食作用以及对生长发育的影响和减少幼虫危害力等方面.印楝素乳油0.005 mL/L处理对成虫的忌避率为78.3%,对幼虫的选择性和非选择性拒食率分别为71.8%和62.9%,幼虫总取食量是对照的59.0%,使小菜蛾种群趋势指数(I值)降为2.4,干扰作用控制指数(1lpc)为0.1079.采用状态空间分析法就印楝素乳油施用后小菜蛾种群数量动态的模拟分析亦表明,其显著的控制作用表现在种群发展初期对成虫的忌避作用.     

Importance of soil-water relations in assessing the endpoint of bioremediated soils

This study was conducted during 1992–1994 under semi-arid conditions in Burkina Faso. Our aim was to assess the influence of different mulch materials on soil variables affecting crop growth; i.e. water content, nutrient contents and temperature. The grain yield of Sorghum bicolor was used as a bioindicator, i.e. as an integrated measure of mulch effects.Six treatments were tested, two of which were leaf mulches of special interest for agroforestry. The treatments were chosen to represent mulch materials differing in nutrient content and decomposability (assumed to influence the duration of the impact on soil water content and temperature). The treatments were as follows: (1) control (no addition), (2) Azadirachta indica (neem) leaves, (3) neem leaves + aerobic compost of sorghum straw, (4) aerobic compost, (5) Acacia holocericea (acacia) phyllodes, and (6) wild grass. The mulching rate was 5 t dry matter ha^-1, and base mineral fertilizers were applied to all plots.It was shown that the neem leaves, neem leaves + compost, wild grass and acacia phyllodes treatments all significantly influenced the soil by conserving water and reducing temperatures compared with the control or the treatment with compost alone. Plots treated with either neem leaves, neem leaves + compost or compost alone gave higher yields than the three other treatments, generally poorer in nutrients, between which there was little difference. Neem leaves gave the numerically highest response: 1.54 × control, corresponding to a grain yield increase of 554 kg dry mass ha^-1 yr^-1 when averaged over the three years of study.Thus, yields did not always increase in spite of increased soil moisture and decreased soil temperatures. It was concluded that nutrients were more limiting than water or high soil temperatures under the conditions studied. The highest yields were achieved with a mulch that combines high nutrient delivery with water conservation and temperature reduction, namely mulch from neem leaves.     

The effect of neem (Azadirachta indica A. Juss) oil on oviposition, development and reproductive potentials of Sesamia calamistis Hampson (Lepidoptera: Noctuidae) and Eldana saccharina Walker (Lepidoptera: Pyralidae)

Abstract 1 The effect of different treatments of neem oil (0, 0.075, 0.1 and 0.15 mL/plant) and their persistence (0, 5 and 10 days after application; DAA) on the oviposition behaviour and the bionomics of the noctuid Sesamia calamistis and the pyralid Eldana saccharina were tested in laboratory and greenhouse experiments. 2 For most variables, no difference was found between DAA, showing that the treatments had a long‐term effect, and pooled analyses across DAA were performed. Compared with the control (0 mL/plant), mean reductions due to neem in numbers of egg batch and eggs laid were 70 and 88% for S. calamistis and 50 and 49% for E. saccharina, respectively, but no differences were found among neem concentrations. 3 For both species, larval and pupal development time was shortest in the control and longest with the highest oil concentration. Immature survival, larval weight and fecundity were highest in the control and similar in the neem treatments. 4 No differences were found in sex ratios. Egg viability was highest in the control (approximately 87%) and lowest (72%) with the highest oil concentration. As a result of lower fecundity and longer developmental time, on average, the intrinsic rates of increase in the neem treatments were 30% lower than in the control. 5 In view of the low oviposition rates, immature survival, fecundity and egg viability in the neem treatments, and the relatively high persistence of neem oil, it can be expected that the reduction in densities of the two borers species in the field will be considerable.     

PEG／（NH4）2SO4双水相体系在加杨叶总黄酮萃取分离中的应用

目的：寻找加杨叶粗提液中的总黄酮的有效方法。方法：利用双水相体系萃取分离、紫外分光光度法直接测定。结果：萃取分离加杨叶总黄酮的最佳双水相体系是25％PEG400与12％（NH4）2SO4,最佳萃取条件为：pH=9,NaCl的添加量为3％,粗提液3mL,温度25℃。结论：该方法的相对标准偏差（RSD）≤0．28％（n=5）,具有良好的精密度和选择性,为黄酮类化合物萃取分离的一种有效方法。     

Potential for habituation to a neem-based feeding deterrent in Japanese beetles, Popillia japonica

We tested the potential for the Japanese beetle, Popillia japonica Newman, to habituate to a neem-based feeding deterrent applied to foliage of linden, Tilia cordata L., a preferred host for the adults. Female beetles' consumption of control foliage versus foliage treated with either a low or high rate of neem insecticide, corresponding to 9 or 39 pm azadirachtin, respectively, was tested in a series of 4-h choice or no-choice tests over four successive days. In another experiment, females were conditioned for 22 h with either control foliage, leaves treated with the low rate, or a mixture of both treated and untreated leaves. Deterrence of either the low or high rate of neem to these beetles was then evaluated in choice tests with control foliage, as before. In choice tests, mean consumption of control foliage was always greater than for treated foliage, regardless of rate. There was, however, proportionately more feeding on foliage treated with the high rate upon successive exposures. In no-choice tests, beetles initially deterred by the low rate were not significantly deterred by that rate by the third and fourth days of the experiment. Finally, beetles conditioned by exposure to leaves treated with the low rate were not deterred by that rate in a subsequent choice test, although they were deterred by the higher rate. Despite these trends, we suggest that Japanese beetles' polyphagy and mobility probably would reduce the likelihood for habituation to neem-based feeding deterrents in the field.     

Growth and insect assays of Beauveria bassiana with neem to test their compatibility and synergism

Beauveria bassiana is being used as a biopesticide for many insect pests. Neem oil (azadirachtin) is an eco-safe popular botanical pesticide. A biopesticde with a neem compatible isolate of B. bassiana will enable their simultaneous use in pest management. A sample of 30 isolates of B. bassiana from culture collections was screened for compatibility with a commercial formulation of neem oil (Margoside®) at the field recommended dose (0.3%, v/v). Compatibility was tested in vitro through germination and growth assays. In all isolates, conidial germination was delayed but not significantly decreased by neem. In the growth assays, 23 isolates were found compatible with neem. In the neem sensitive isolates, growth was decreased but not totally inhibited. The effect of combined treatment with B. bassiana and neem in comparison to single treatments with either of them on Spodoptera litura Fabricius was tested in laboratory bioassays. The combined treatment was found to have synergistic effect on insect mortality when a B. bassiana isolate compatible with neem was used, while, with an isolate sensitive to neem, an antagonistic effect was observed.     

Effect of ration level on nitrogen excretion, nitrogen retention and efficiency of nitrogen utilization for growth in largemouth bass (Micropterus salmoides)

Largemouth bass ( Micropterus salmoides ) with an average weight of 45.5 g were used to study ration level effects on nitrogen excretion, nitrogen retention, and gross efficiency of utilization of nitrogen for growth. Bass were starved 3 to 4 days and then each bass was placed into an aquarium containing a known volume of water. One day after the fishes were placed in aquaria, nitrogen excretion rates were determined; this rate is the maintenance nitrogen excretion. Each fish was then fed one or more shiners ( Notropis cornutus ); fish were fed only once. Nitrogen excretion measurements were made daily until the rates were similar to maintenance rates. The nitrogen excretion rates for each day after feeding which were above the maintenance nitrogen excretion were combined and reflect the total nitrogen excretion for a given ration level. All ration levels were converted to nitrogen consumption in mg and nitrogen absorption was calculated from subtracting the average faecal nitrogen from nitrogen consumption. From data on nitrogen consumption, nitrogen absorption, nitrogen excretion, and faecal nitrogen, calculations were made for nitrogen retention and gross efficiency of utilization of nitrogen for growth.
As ration level and nitrogen absorption increased, nitrogen excretion increased and is described by the equation, Y = 8.56+0.40 X , where Y is total nitrogen excretion and X is nitrogen absorption. Nitrogen retention also increased with nitrogen absorption and is described by the equation, Y =–8.57+0.60 X , where Y is nitrogen retention and X is nitrogen absorption. Efficiency increases rapidly above maintenance, but levels off at higher ration levels and approaches an asymptote of 60%.     

Induction of defence-related biochemical changes in okra leaves to powdery mildew disease by several plant-derived agents

Certain plant-derived agents (PDA) which could induce resistance in okra leaves against powdery mildew (Erysiphe cichoracearum) and biochemical changes in treated leaves were investigated during 2011 and 2012 growing seasons. At the two-leaf old, four- and eight-week leaves of the greenhouse-grown okra plants were sprayed with either PDA two days before inoculation with conidia. Among all tested PDA, neem seed oil (NSO) caused the highest protection, followed by jojoba oil (JO) and extract of Reynoutria sachalinensis. Moreover, levels of total protein, activity of peroxidase, polyphenyloxidase and chitinase and total phenols content of treated two-leaf old highly increased after application of NSO and JO, but not by the pathogen (untreated control). Finally, based on conidia germination, lack of the fungitoxic effect of JO and RE and also the slight effect of NSO (9–13.75%) may demonstrate the main role of these agents for inducing resistance through the activation of biochemical defence in treated leaves.     

In vitro evaluation of native entomopathogenic fungi and neem (Azadiractha indica) extracts on Spodoptera frugiperda

The control of Spodoptera frugiperda is based on synthetic insecticides, so some alternatives are the use of entomopathogenic fungi (EF) and neem extract. The objective of the study was to evaluate in vitro effectiveness of native EF and neem extracts on S. frugiperda larvae. Six EF were identified by DNA sequencing of ITS regions from three EF (Fusarium solani, Metarrhizium robertsii, Nigrospora spherica and Penicillium citrinum). They were evaluated in concentrations of 1 × 10⁸ spores/ mL. In addition, a second bioassay was carried out evaluating only F. solani, M. robertsii and N. sphaerica and the addition of vegetable oil. On the other hand, extraction of secondary metabolites from neem seed (Azadirachta indica) was carried out by performing, mass (g) and solvent volume (mL ethanol and water) combinations, which were subjected to microwaves and ultrasound. Subsequently, these extracts were evaluated in concentrations of 3%, 4% and 5%. A survival analysis was performed for each of the bioassays. With respect to the results of the first bioassay, F. solani obtained a probability of survival of 0.476 on the seventh day, while in the second bioassay, M. robertsii obtained 0.488 survival probability. This suggests that the expected percentage of larvae that stay alive on the sixth day is 48.8%. However, in the evaluation of the neem extract the combination 1:12/70% to 4% caused 84% mortality of larvae. The use of native HE and neem extracts has potential for the control of S. frugiperda.     

红果参叶中总黄酮的提取工艺初步探讨

目的:研究红果参叶中总黄酮的最佳提取工艺条件。方法:利用单因素和正交试验,考察提取时间、乙醇溶液体积分数、液固比3个因素对总黄酮得率的影响。结果:红果参叶中总黄酮的最佳提取工艺条件为:85%(体积分数)的乙醇作为提取溶剂、提取时间10 min、料液比1∶30(g/mL)。在此条件下,总黄酮提取率可达4.76%。结论:乙醇超声法可用于红果参叶中总黄酮的提取,其中料液比对提取率的影响最大。     

Evaluation of neem, Azadirachta indica, with and without water management, for the control of culicine mosquito larvae in rice-fields

Applications of neem, Azadirachta indica (Meliaceae), to rice-fields were evaluated with the dual objective of controlling the culicine mosquito vectors of Japanese encephalitis virus (JEV) and enhancing the grain yield. Since crude neem products deteriorate under improper storage conditions, a laboratory bioassay was developed to screen neem cake powder against mosquito larvae, Culex quinquefasciatus. Only samples of neem giving over 90% bioassay mortality were used in field trials. When good quality neem cake powder was applied at the dose of 500 kg/ha, either alone or coated over urea, there was a striking reduction in the abundance of late instar culicine larvae and pupae. Only fourteen pupae were obtained over a period of 13 weeks in neem cake powder treated plots, and four in those treated with neem coated urea, compared with 101 in control plots. Both treatments were significantly less than the control, but on par with one another. In another field trial, neem cake coated urea was tested at 500 and 250 kg neem/ha in combination with water management practices. No reduction in efficacy was noted at the lower dose. Larval abundance in plots under water management alone did not differ significantly from the controls, but was significantly reduced when water management was combined with neem products. Two stable formulations, 'Neemrich-I' (lipid rich) and 'Neemrich-II' (azadirachtin rich), also gave good suppression of immature culicines. All the treatments with neem also gave higher grain yield than the control.(ABSTRACT TRUNCATED AT 250 WORDS)