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％。     

苦瓜素Ⅰ对亚洲玉米螟幼虫酚氧化酶活性的抑制作用

为了探讨苦瓜素类化合物抑制昆虫生长发育的作用机制,测定了苦瓜叶乙酸乙酯萃取物和苦瓜素Ⅰ对亚洲玉米螟Ostrinia furnacalis幼虫体内酚氧化酶活性的抑制作用以及苦瓜素Ⅰ、苦瓜素Ⅱ和苦瓜皂苷元L对亚洲玉米螟幼虫离体酚氧化酶活性的抑制作用。结果表明,苦瓜叶乙酸乙酯萃取物和苦瓜素Ⅰ均能明显抑制亚洲玉米螟幼虫酚氧化酶的活性。用含有不同浓度苦瓜叶乙酸乙酯萃取物和苦瓜素I的人工饲料饲喂亚洲玉米螟3龄幼虫48 h后,苦瓜叶乙酸乙酯萃取物和苦瓜素Ⅰ对亚洲玉米螟幼虫体内酚氧化酶活性的抑制中浓度IC_(50)分别为0.17%和0.34%。苦瓜素Ⅰ和苦瓜素Ⅱ对亚洲玉米螟离体酚氧化酶的活力也表现出明显的抑制作用,抑制中浓度IC_(50)分别为169.28μg/mL和1182.08μg/mL。苦瓜素I的抑制作用明显强于苦瓜素Ⅱ。苦瓜叶提取物及其活性成分苦瓜素Ⅰ对亚洲玉米螟幼虫酚氧化酶活性的抑制作用可能是其抑制昆虫生长发育的主要机制之一。     

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。     

复方苦参植物素水剂对十字花科蔬菜几种害虫的活性及田间防效

室内毒力测定结果表明,复方苦参植物素对菜蚜(若蚜)、菜青虫有很高的毒力,LC50分别为1．02mg／L和1．37mg／L,对斜纹夜蛾幼虫的毒力较低,LC50为11．65mg／L。复方苦参植物素不杀斜纹夜蛾的卵,不影响卵的孵化率,但对初孵幼虫有较好的杀伤效果。斜纹夜蛾幼虫随着虫龄的增大,对复方苦参植物素的敏感性下降。复方苦参植物素100mg／L,斜纹夜蛾幼虫非选择性和选择性拒食作用分别为96．86％和78．97％,作用方式以触杀作用为主,胃毒作用为辅。田间试验表明,复方苦参植物素200～300倍,对菜青虫和菜蚜的防效在90％左右,持效期10d。     

曲酸对台湾乳白蚁纤维素酶活的抑制与应用研究

为了探究有害白蚁的安全防控新技术,本文研究了生物源活性物质曲酸对建筑结构主要害虫台湾乳白蚁纤维素酶活性的抑制效果。在室内条件下选择1%曲酸溶液滤纸饲喂白蚁,分别于饲喂6 h、12 h、1 d、3 d、5 d、7 d时收集白蚁消化道,采用还原糖法测定了白蚁消化道的滤纸酶活性(FPA)及内切β-1,4-葡聚糖酶(EG)、β-葡萄糖苷酶(BG)和纤维二糖水解酶(CBH)的比活力,并观测记录供试白蚁的体重与死亡率变化。结果显示,除6 h处理样的FPA和CBH活性影响不显著外,其余处理对白蚁纤维素酶活性均有显著的抑制作用,且随处理时间的延长曲酸对台湾乳白蚁纤维素酶活抑制率增强,抑制率显示FPAEG≥BGCBH。曲酸处理7d后,白蚁活动能力明显减弱,工蚁体重显著降低且死亡率显著升高。曲酸与氟虫脲联合喂食处理对台湾乳白蚁FPA和EG活性的抑制效果高于氟虫脲单独饲喂台湾乳白蚁,而且白蚁死亡率也显著提高。研究表明曲酸对于白蚁纤维素酶活性具有抑制效果,对于氟虫脲具增效作用,可为白蚁治理新技术的研究提供参考。     

中药大黄的生物化学研究——蒽醌衍生物对线粒体NADH氧化酶和琥珀酸氧化酶的抑制作用

 实验结果表明:(1)大黄素对线粒体NADH氧化酶和琥珀酸氧化酶有很强的抑制作用,其作用随药物浓度的增大而增强,并呈双曲线型,50％抑制浓度分别为2.5μg/ml和11.5μg/ml。而其它四种蒽醌衍生物如大黄酸、芦荟大黄素、大黄素甲醚和大黄酚对这两种氧化酶的抑制作用不明显,药物浓度为60μg/ml,抑制率均低于20％。(2)拮抗实验表明:核黄素、牛血清蛋白(BSA)能拮抗大黄素对线粒体NADH氧化酶的抑制作用。核黄素(3.3×10~(-4)mol/L)和BSA(1.6mg/ml)对大黄素抑制NADH氧化酶的恢复率分别为50.3％和44.6％,且恢复率随拮抗剂浓度的增加而增加。     

溴氰菊酯对方形黄鼠蚤不同发育期的毒效测定

实验证明,溴氰菊酯对方形黄鼠蚤松江亚种各发育期有不同程度的毒杀作用:5ppm浸渍法对卵的校正死亡率为92％;0.05ppm混药法对幼虫的校正死亡率为91％;50ppm混药法对茧蛹的校正死亡率为52％;点滴法对2日龄吸血成蚤的LD_(50):雌虫为1.17×10~(-6)μg/只,雄虫为1.08×10~(-6)μg/只。药膜法:1ppm以上在玻璃表面、10ppm以上在滤纸面,有长达2年的残效期。在土壤表面,2mg/m~2为灭蚤的有效剂量,残效期在5个月左右。     

苦瓜素Ⅰ对亚洲玉米螟的生物活性及对其幼虫体内代谢酶活性的影响

【目的】为研究苦瓜素Ⅰ对亚洲玉米螟 Ostrinina furnacalis (Güenée)的生物活性和体内相关酶活性的影响。【方法】采用饲料混药法测定了苦瓜素Ⅰ对亚洲玉米螟生长发育和繁殖的影响,并以生命表的方法评价了苦瓜素Ⅰ对亚洲玉米螟实验种群增长的控制作用;采用酶标仪测定了苦瓜素Ⅰ对亚洲玉米螟幼虫海藻糖酶和磷酸酯酶活性的影响。【结果】用含0.25, 0.5, 1.0, 2.0和4.0 mg/g浓度苦瓜素Ⅰ的人工饲料饲喂亚洲玉米螟3龄幼虫3 d,幼虫的存活率明显降低, LC₅₀为3.2 mg/g;对幼虫体重增长的抑制作用显著,在4.0 mg/g浓度下,第1, 2和3 天体重增长的抑制率分别为76.87%, 78.24%和79.94%,且发育历期明显延长;苦瓜素Ⅰ各浓度处理组中亚洲玉米螟蛹的历期和成虫寿命与对照相比差异不显著,但苦瓜素Ⅰ明显降低了亚洲玉米螟雌成虫的产卵量,4.0 mg/g浓度下,产卵抑制率高达73.55%。苦瓜素Ⅰ对亚洲玉米螟幼虫海藻糖酶、酸性磷酸酯酶和碱性磷酸酯酶活性均有明显的抑制作用,处理24, 48和72 h后,对亚洲玉米螟幼虫海藻糖酶活性的IC₅₀分别为3.8, 2.9和4.9 mg/g;对酸性磷酸酯酶活性的IC₅₀分别为3.1, 2.6和1.5 mg/g,对碱性磷酸酯酶活性的IC₅₀分别为3.3 ,1.9和3.6 mg/g。【结论】苦瓜素Ⅰ能显著抑制亚洲玉米螟幼虫的生长发育及成虫的生殖力,使其实验种群的增长受到明显控制。苦瓜素Ⅰ抑制亚洲玉米螟幼虫体内海藻糖酶和磷酸酯酶活性是其作用机制之一。     

棉酚对棉铃虫生长及其寄生物齿唇姬蜂发育的影响(英文)

以中国北方棉区的主要害虫棉铃虫Helicoverpaarmigera（Hbner）及其内寄生蜂棉铃虫齿唇姬蜂Campoletischlorideae（Uchida）为试虫,研究了棉花重要抗虫次生性物质棉酚对棉铃虫生长和齿唇姬蜂发育的影响。0．1％的棉酚对棉铃虫幼虫有生长刺激作用,0．5％的棉酚则对棉铃虫幼虫生长有抑制作用。齿唇姬蜂成虫在寄生时对寄主大小有较严格的选择性,92％的被寄生幼虫体重小于18mg。0．1％的棉酚使寄主适合寄生期缩短10．75％;0．5％棉酚使寄主适合寄生期延长28．15％。棉酚对齿唇姬蜂发育有负效应。0．1％棉酚对寄主的生长刺激作用,不能使蜂成虫体重显著增加,但可显著延长蜂卵和幼虫期,缩短蛹期;高浓度的生长抑制作用,导致蜂成虫体重显著减轻,蛹期缩短,蜂卵和幼虫期亦显著延长。据此,对棉花抗虫性与生物防治在害虫综合防治实践中应用的协调性进行了讨论。     

曲酸高产菌株的诱变选育

以紫外线和氮离子注入作为诱变手段对曲酸产生菌黄曲霉CICC2242进行诱变处理,筛选出一株高产菌株N83。曲酸产量由初始的12．4g／L提高到19．4g／L,提高了56．5％;遗传稳定性实验结果表明,N83遗传性状稳定良好。该结果表明氮离子注入诱变是获得高产曲酸的有效途径。     

Production of polymalic acid and malic acid by Aureobasidium pullulans fermentation and acid hydrolysis

Malic acid is a dicarboxylic acid widely used in the food industry and also a potential C4 platform chemical that can be produced from biomass. However, microbial fermentation for direct malic acid production is limited by low product yield, titer, and productivity due to end‐product inhibition. In this work, a novel process for malic acid production from polymalic acid (PMA) fermentation followed by acid hydrolysis was developed. First, a PMA‐producing Aureobasidium pullulans strain ZX‐10 was screened and isolated. This microbe produced PMA as the major fermentation product at a high‐titer equivalent to 87.6 g/L of malic acid and high‐productivity of 0.61 g/L h in free‐cell fermentation in a stirred‐tank bioreactor. Fed‐batch fermentations with cells immobilized in a fibrous‐bed bioreactor (FBB) achieved the highest product titer of 144.2 g/L and productivity of 0.74 g/L h. The fermentation produced PMA was purified by adsorption with IRA‐900 anion‐exchange resins, achieving a ～100% purity and a high recovery rate of 84%. Pure malic acid was then produced from PMA by hydrolysis with 2 M sulfuric acid at 85°C, which followed the first‐order reaction kinetics. This process provides an efficient and economical way for PMA and malic acid production, and is promising for industrial application. Biotechnol. Bioeng. 2013; 110: 2105–2113. © 2013 Wiley Periodicals, Inc.     

New highly toxic bile acids derived from deoxycholic acid,chenodeoxycholic acid and lithocholic acid

We have prepared a new panel of 23 BA derivatives of DCA, chenodeoxycholic acid (CDCA) and lithocholic acid (LCA) in order to study the effect of dual substitution with 3-azido and 24-amidation, features individually associated with cytotoxicity in our previous work. The effect of the compounds on cell viability of HT-1080 and Caco-2 was studied using the 3-[4,5-dimethylthizol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Compounds with high potency towards reduction of cell viability were further studied using flow cytometry in order to understand the mechanism of cell death. Several compounds were identified with low micromolar IC₅₀ values for reducing cell viability in the Caco-2 and HT1080 cell lines, making them among the most potent BA apoptotic agents reported to date. There was no evidence of relationship between overall hydrophobicity and cytotoxicity supporting the idea that cell death induction by BAs may be structure–specific. Compounds derived from DCA caused cell death through apoptosis. There was some evidence of selectivity between the two cell lines studied which may be due to differing expression of CD95/FAS. The more toxic compounds increased ROS production in Caco-2 cells, and co-incubation with the antioxidant N-acetyl cysteine blunted pro-apoptotic effects. The properties these compounds suggest that there may be specific mechanism(s) mediating BA induced cell death. Compound 8 could be useful for investigating this phenomenon.     

Separation and simultaneous determination of nalidixic acid, hydroxynalidixic acid and carboxynalidixic acid in serum and urine by micellar electrokinetic capillary chromatography

Separation in capillary electrophoresis is governed by various factors, including buffer type, buffer concentration, pH, temperature, voltage and micelles. Through proper adjustment of these parameters, nalidixic acid and its two major metabolites, 7-hydroxynalidixic and 7-carboxynalidixic, could be separated by micellar electrokinetic capillary chromatography using an electrophoretic electrolyte consisting of 50 mM borate buffer (pH 9) containing 25 mM sodium dodecyl sulphate and 10% acetonitrile. A linear relationship between concentration and peak area for each compound was obtained in the concentration range 0.15–100 μg ml⁻¹, with a correlation coefficient greater than 0.999 and detection limits in the 0.2–0.7 ng ml⁻¹ range. Intra- and inter-day precision values of about 0.8–1.2% RSD (n=11) and 1.3–2.0% RSD (n=30), respectively, were obtained. The method has been applied to the analysis of nalidixic acid and its two major metabolites in serum and urine with limits of sensitivity lower than 0.8 ng ml⁻¹.     

Analysis of creatinine, vanilmandelic acid, homovanillic acid and uric acid in urine by micellar electrokinetic chromatography

A simultaneous determination of vanilmandelic acid, homovanillic acid, creatinine and uric acid using capillary electrophoresis was investigated. The optimum conditions of buffer concentration, pH and surfactant concentration were studied, and high resolution was obtained using a 30 mM phosphate buffer (pH 7.0) containing 150 mM sodium dodecyl sulfate. The detection was by UV absorbance at 245 nm and the column was a fused-silica capillary of 67 cm×75 μm I.D.. The determination of these metabolites in human urine was completed within 15 min without any interferences.     

Sempervirenic acid,a diterpene acid from Solidago sempervirens

Sempervirenic acid, a new diterpene has been isolated from Solidago sempervirens and its structure determined by spectroscopic methods and chemical conversions to be 3β-acetoxy-labda-7,13-diene-15-oic acid.     

Molecularly imprinted polymer using-p-hydroxybenzoic acid, p-hydroxyphenylacetic acid and p-hydroxyphenylpropionic acid as templates.

Molecularly imprinted polymers (MIPs) using p-hydroxybenzoic acid (p-HB), p-hydroxyphenylacetic acid (p-HPA) and p-hydroxyphenylpropionic acid (p-HPPA) as templates were synthesized. The performance of the templates and their analogues on polymer-based high performance liquid chromatography (HPLC) columns was studied. The imprinting effect of the MIP using p-HB as template is more obvious than that of MIP using either p-HPA or p-HPPA as template, and the mixture of p-HB and p-HPA can be well separated on the MIP using p-HB as template, but not on the blank. Interestingly, the recognition of MIP (p-HB as the template) to p-HB showed a synergistic effect. The retention factor of p-HB is not the sum of those of phenol and benzoic acid. We also found that the imprinting effect decreased when increasing the concentration of acetic acid in mobile phase. The possible reason is that acetic acid molecules occupied the binding sites of the polymer, thereby decreasing the concentration of binding sites. Furthermore, polymers, which showed specificity to 3,4-dihydroxybenzoic acid, can be prepared with p-HB as template. It is thus possible to synthesize a specific polymer for a compound that is either expensive or unstable by using a structurally similar compound as template.     

Alanyl turnover from lipoteichoic acid to teichoic acid in Staphylococcus aureus

Abstract The metabolism of d -alanyl substituents of lipoteichoic acid (LTA) and teichoic acid was studied in Staphylococcus aureus . Double labelling with [³H]glycerol and d -[¹⁴C]alanine revealed that during the chase LTA was stable whereas its ¹⁴C label rapidly decreased. Half-time comparison indicated an enzyme- rather than a base-catalyzed process. Correlated with the loss of [¹⁴C]alanine from LTA was an increase of the radioactivity in wall-linked alanine ester which, after hydrolysis with HF, proved to be linked to teichoic acid. These results suggest that LTA-alanine is the donor for alanine esterification of teichoic acid. In connection with previous data we hypothesize that the loss of alanine from LTA is compensated by de novo incorporation.     

Glucuronic acid conjugates

The methods of assay in body fluids of 1-β-alkyl, 1-β-phenyl and 1-β-acyl glucuronic acids (“glucuronide conjugates”) have been reviewed. Most of the 78 references cited (from the literature of the period 1990–1997) concern the glucuronide conjugates of drug metabolites, and these have been considered, for reasons of accessibility, within sections of individual drug classes such as analgesics, anti-cancer agents and opioids. Other glucuronide conjugates are considered under “miscellaneous compounds”. A few gas chromatography and capillary electrophoresis methods are described, but the major technique of assay (62 citations) is reversed-phase high-performance liquid chromatography.     

Docosahexaenoic acid synthesis from n-3 fatty acid precursors in rat hippocampal neurons

Docosahexaenoic acid (DHA), the most abundant n-3 polyunsaturated fatty acid in the brain, has important functions in the hippocampus. To better understand essential fatty acid homeostasis in this region of the brain, we investigated the contributions of n-3 fatty acid precursors in supplying hippocampal neurons with DHA. Primary cultures of rat hippocampal neurons incorporated radiolabeled 18-, 20-, 22-, and 24-carbon n-3 fatty acid and converted some of the uptake to DHA, but the amounts produced from either [1-¹⁴C]α-linolenic or [1-¹⁴C]eicosapentaenoic acid were considerably less than the amounts incorporated when the cultures were incubated with [1-¹⁴C]22:6n-3. Most of the [1-¹⁴C]22:6n-3 uptake was incorporated into phospholipids, primarily ethanolamine phosphoglycerides. Additional studies demonstrated that the neurons converted [1-¹⁴C]linoleic acid to arachidonic acid, the main n-6 fatty acid in the brain. These findings differ from previous results indicating that cerebral and cerebellar neurons cannot convert polyunsaturated fatty acid precursors to DHA or arachidonic acid. Fatty acid compositional analysis demonstrated that the hippocampal neurons contained only 1.1–2.5 mol% DHA under the usual low-DHA culture conditions. The relatively low-DHA content suggests that some responses obtained with these cultures may not be representative of neuronal function in the brain.     

Peptidases and amino acid catabolism in lactic acid bacteria

The conversion of peptides to free amino acids and their subsequent utilization is a central metabolic activity in prokaryotes. At least 16 peptidases from lactic acid bacteria (LAB) have been characterized biochemically and/or genetically. Among LAB, the peptidase systems of Lactobacillus helveticus and Lactococcus lactis have been examined in greatest detail. While there are homologous enzymes common to both systems, significant differences exist in the peptidase complement of these organisms. The characterization of single and multiple peptidase mutants indicate that these strains generally exhibit reduced specific growth rates in milk compared to the parental strains. LAB can also catabolize amino acids produced by peptide hydrolysis. While the catabolism of amino acids such as Arg, Thr, and His is well understood, few other amino acid catabolic pathways from lactic acid bacteria have been characterized in significant detail. Increasing research attention is being directed toward elucidating these pathways as well as characterizing their physiological and industrial significance.