Fecal volatiles as part of the aggregation pheromone complex of the desert locust,Schistocerca gregaria (Forskal) (Orthoptera: Acrididae)

Olfactometric bioassays showed that nymphs of crowded desert locusts,Schistocerca gregaria, aggregated in response to volatiles derived from their feces and to volatiles emitted from the feces of young adults, but were indifferent to volatiles emitted by older adult feces. On the other hand, young and older adults were not only responsive to their own fecal volatiles but also cross-responsive to each other's and that of the nymphs. Charcoal-trapped volatiles from the feces and synthetic blends of the fecal volatiles also elicited similar responses. Young adults responded moderately to a blend of nymphal volatiles and those derived from nymphal feces. GC-EAD and GC-MS analysis of the trapped volatiles revealed the presence of guaiacol and phenol as predominant electrophysiologically active components of nymphal and young adult feces. Fecal volatiles of older adult contained phenylacetonitrile in addition to guaiacol and phenol, which were present in relatively lower proportion. These results suggest that fecal volatiles are part of the aggregation pheromone complex of the desert locust, which includes the pheromone blends produced by nymphs and older adults, respectively.     

Aggregation pheromone system of nymphal gregarious desert locust,Schistocerca gregaria (forskål)

Hexanal, octanal, nonanal, decanal, hexanoic acid, octanoic acid, nonanoic acid, and decanoic acid were identified in the volatile emissions from fifth instars ofSchistocerca gregaria by coupled gas chromatography-electroantennography (GC-EAD) detection and coupled GC-mass spectrometry (MS). In laboratory assays, synthetic blends of the eight compounds, with acids and aldehydes tested separately, evoked strong aggregation responses from fifth instars, similar to responses evoked by a crude volatile extract of the nymphs. A nymphal fecal volatile phenolic blend of guaiacol and phenol, which we have previously shown to evoke an aggregative response from different stages of the insect, significantly synergized the activity of the blend of eight compounds, suggesting mutually augmentative roles for nymphal and fecal volatiles in evoking aggregation. These results indicate that the aggregation behavior of gregarious second to fifth instars is modulated by three sets of pheromonal compounds: aldehydes and acids emitted by the nymphs themselves and phenols associated with their feces.     

Analysis of peach bark volatiles and their electroantennogram activity with lesser peachtree borer,Synanthedon pictipes (Grote and Robinson)

Bark volatiles from two peach cultivars (Bisco and Redskin) were obtained by vacuum steam distillation and fractionated by preparative gas chromatography. The fractions were then assayed with the electroantenno- gram (EAG) method on antennae of female lesser peachtree borer [Synanthedon pictipes (Grote and Robinson)]. With both cultivars, two fractions elicited the largest responses. Analysis of this material by GC-MS revealed a complex mixture made up of aromatic alcohols, esters, ketones, and acids, as well as phenols, aliphatic aldehydes, and aliphatic acids. EAG responses to pure samples of all identified components were recorded, and many of these compounds were found to be quite active. Among the most stimulatory were guaiacol, methyl benzoate, and l-phenyl-1,2-propanedione. Also tested were six-carbon aliphatic aldehydes and alcohols which are components of the foliar tissue of most plants. Of these, 1-hexanol showed moderate activity, while the aldehydes and unsaturated alcohols were only weakly active.Lepidoptera: Sesiidae.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

三种乳过氧化物酶检测方法的比较

本文比较了ABTS检测法、TMB检测法、愈创木酚检测法的线性关系、检出限、精密度,以及对原料乳及其乳制品中的乳过氧化物酶(LP)测定。研究表明,ABTS检测法中LP浓度在2~5.0 mg/L范围内线性关系良好,R2=0.9935;检出限为0.210 mg/L;批内和批间变异系数分别小于4%和7%。TMB检测法中LP浓度在2~12 mg/L范围内线性关系良好,R2=0.9897;检出限为0.612 mg/L;批内和批间变异系数分别小于4%和5%。愈创木酚检测法中LP浓度在8~20.0 mg/L范围内线性关系良好,R2=0.9857;检出限为1.095 mg/L;批内和批间变异系数分别约为6%和7%。ABTS法与TMB法的线性关系、检出限、精密度均较愈创木酚法好。因此,以ABTS与TMB作为检测LP的显色底物,更为简便、快速、准确。      

5-硝基愈创木酚的合成工艺改进

为合成高纯度的 5 硝基愈创木酚 ,对以愈创木酚为原料与硝酸直接硝化的方法进行了改进 :原料经酰化 ,硝化 ,水解和酸化合成了题述产物。讨论了酰化、硝化反应的影响因素 ,确定了最佳合成工艺条件 :用氨基磺酸作乙酰化反应的催化剂 ,愈创木酚用量 12 .4g ,酰化剂乙酸酐用量 18.4g ,反应温度 70～ 80℃ ;硝化反应温度为 5 0℃ ,愈创木酚 硝酸 冰醋酸 (质量比 ) =1∶1.6∶2 .1。结果表明 ,在此条件下 5 硝基愈创木酚的最终收率达 63 %以上 ;重结晶后经HPLC测定 ,其纯度达 99%。     

生物油模型化合物催化共裂解制烃的研究

以愈创木酚为生物油模型化合物,正丁醇为共裂解物,利用GC-MS等方法研究了共裂解产物中的有机物含量、油相产物的热值和含水量,分析了共裂解物原料比和原料含水量对共裂解反应的影响,探究了以愈创木酚为代表的生物油模型化合物的催化共裂解机理。实验结果表明,共裂解法可提高油相产物的品质及烃类收率,当m(愈创木酚)∶m(正丁醇)从2∶1降至1∶2时,油相产物中含氧化合物相对含量(w)从35.7%降至12.7%,但烃类总收率从19.5%降至15.0%,油相产物热值最高为43.1 MJ/kg、含水量(w)从2.73%降至0.91%。共裂解物的烃类总收率随原料含水量的增大而快速降低,油相产物中的含氧化合物含量逐渐增大,品质快速下降。生物油高含水量是阻碍生物油通过共裂解法提质改性的主要原因。     

TiO2光催化降解紫丁香醇的定量分析

在圆柱型光催化反应器中,以UV-A light（功率11W,波长253.7,nm）作为光源,对含有紫丁香醇模型物的木素类有机废水进行光催化降解实验,研究讨论了悬浮体系中TiO2光催化降解紫丁香醇木素的反应特性.实验结果表明,紫丁香醇结构中部分双甲氧基在光照的条件下,与苯环发生了断裂,生成了具有单甲氧基结构的中间体——愈创木酚和一些其他低分子有机物;通过联立公式对降解过程中的紫丁香醇和愈创木酚的浓度进行定量分析.     

5-溴-2-甲氧基苯酚的合成

5-溴-2-甲氧基苯酚是一种重要的农药、医药中间体,本文以邻甲氧基苯酚为原料,乙酰化、溴化、脱保护得到5-溴-2-甲氧基苯酚,总收率为64．3％,产物的结构通过1HNMR、13CNMR及元素分析进行验证。     

Pyrolysis of kraft lignin in the presence of molten ZnCl2-KCl mixture

Pyrolysis of kraft lignin was carried out using small reactors with an added ZnCl₂-KCl mixture at three levels of temperature, 500°C, 550°C and 600°C, and three levels of salt-to-lignin ratio (SR), 1, 2 and 3. Nineteen kinds of phenolic compound were identified and their quantitative determinations were made by gas chromatography. The yield of gaseous products determined gravimetrically exhibited a strong dependence on the added amount of salt mixture, and its lowest value was obtained at SR of 1. The formation of gaseous products, apparently stemming from decomposition of liquid products and tar, was observed at reaction times longer than 30 min. At SR of 1 and a temperature of 550°C, all phenolic compounds attained their maximum yields almost synchronously at a reaction time of 15 min. Cresol's formation was slightly increased with the amount of added salt mixture. At a temperature of 550°C, cresols and guaiacols decomposed according to a pseudo-first-order lumping model, while catechols did not follow the similar model.