Biosynthesis of eugenol and cinnamic aldehyde in Cinnamomum zeylanicum

Incorporation of [¹⁴C]-phenylalanine and [¹⁴C]-methionine into cinnamon cuttings suggests that synthesis of eugenol from phenylalanine involves exchange of the terminal carbon in the side chain with that from a donor molecule such as methionine whereas synthesis of cinnamic aldehyde incorporates phenylalanine in toto.     

Efficacy and repellency of some essential oils and their blends against larval and adult house flies,Musca domestica L. (Diptera: Muscidae)

House flies are global pests and notoriously difficult to control. Essential oils of vetiver, cinnamon, and lavender and their blends were tested for toxic and repellent effects against larval and adult flies. All of the oils had moderate toxicity for eggs. Mortality of 2^nd instar larvae was 57–78% in dipping assays, 38–100% in contact assays, and 94–100% in treated media. Lavender was less effective (38% mortality) than the others (91–100%) in contact bioassays. Oil blends were not more effective against larvae than individual oils. Vetiver and cinnamon oils were strongly repellent (84 and 78%, respectively) for larvae in treated media. None of the oils were repellent for adult house flies in olfactometer assays, but testing of additional products demonstrated significant repellency for neem oil, p‐menthane‐3,8‐diol (PMD), and vanillin. Contact/fumigant toxicity of vetiver, cinnamon, and lavender oils was 100%, significantly higher than mortality from sunflower oil (67%). Blends of oils were not more effective against adults than the individual oils, but blends diluted with sunflower oil were as effective as the individual oils. Essentials oils of vetiver and cinnamon may have potential for fly management in situations where conventional insecticides cannot be used.     

四种植物精油对黑翅土白蚁触杀和驱避作用

为筛选出高效防治黑翅土白蚁的天然植物精油,减少有机合成农药的使用,该文研究了大蒜精油、肉桂油、丁香油和印楝素油四种植物精油对黑翅土白蚁的触杀效果和驱避作用。结果表明:大蒜精油、肉桂油和丁香油的浓度为5和10 mg·m L~(-1)时,处理2 h后,黑翅土白蚁的校正死亡率达100%,而相同浓度的印楝素油和对照处理的黑翅土白蚁校正死亡率低于5%。随着处理时间延长,浓度为1.25和2.5 mg·m L~(-1)的大蒜精油、肉桂油和丁香油处理6 h时,黑翅土白蚁的校正死亡率仍达100%,而此时对应的印楝素油和对照处理的黑翅土白蚁校正死亡率仅为10%,说明大蒜精油、肉桂油和丁香油对黑翅土白蚁具有较强的触杀效果。大蒜精油、丁香油和肉桂油在处理黑翅土白蚁2 h后LC_(50)值(半致死量)分别为1.572、1.05和1.03mg·m L~(-1),说明肉桂油对黑翅土白蚁的毒性相对最大,触杀效果最好。此外,10 mg·m L~(-1)的大蒜精油、肉桂油、丁香油和印楝素油的驱避试验表明,处理4、6、8和12 h后,大蒜精油、肉桂油和丁香油三精油处理区的黑翅土白蚁数均显著低于对照区的,驱避率总体93%,而对应的印楝素油的驱避率总体28.5%,表明大蒜精油、丁香油和肉桂油三种植物精油对黑翅土白蚁均有显著的驱避活性。综上可知,四种植物精油中大蒜精油、肉桂油和丁香油在防治黑翅土白蚁方面应用潜力很好,是开发绿色环保白蚁防治药剂的可选材料。     

The abundance of ground-dwelling invertebrates in a Victorian forest affected by ‘dieback’(Phytophthora cinnamomi) disease

Abstract Phytophthora cinnamomi (cinnamon fungus) is a pathogenic soil fungus that infects plant communities along the southeastern coast of Australia and the southwestern corner of Western Australia. Infection of native plant communities with P. cinnamomi regularly leads to dramatic changes in both the structural and the floristic characteristics of these communities. This study aimed to assess the effect of P. cinnamomi induced changes in plant community attributes upon the abundance and diversity of invertebrates in an area of open forest in the Brisbane Ranges, Victoria. Pitfall trapping was conducted continuously for 1 week within each season over a 3 year period. Invertebrates were sorted to order level, and abundances were compared between times (season and year) and infection status for taxa with normalized distributions (Coleoptera, Collembola, Dermaptera and ants). Non-parametric comparisons were made for other groups (Aranae, Blattodea, Diptera, Hemiptera, Orthoptera, ant ‘morpho-species’ and unidentified larvae) to assess differences on the basis of infection status. Significant differences on the basis of infection were uncommon and, where identified, elevated abundances were more commonly observed at sites infected by P. cinnamomi. Consistent temporal effects (season and year) were observed in normalized data sets. Abundances both within individual taxa and from pooled counts were generally weakly associated with ground-level habitat features. Overall, the impact of P. cinnamomi on vegetative structure and floristics was not reflected in different abundances of ground-dwelling invertebrates.     

COI序列:影响动物分类学与生态学的DNA barcode

DNA barcode是一段特殊的、可用于物种鉴定的DNA序列.目前在动物中最常用的DNA barcode是细胞色素C氧化酶1号基因(COI)的部分序列.随着标准数据库的建立,基于COI基因的DNA barcode在动物分类学和生态学中得到了广泛应用.但是,采用COI基因作为DNA barcode所隐含的涉及线粒体的进化历史、遗传特性和物种成种时间的默认前提,并非完全成立,由此引发了许多问题.本文阐述了基于COI基因的DNA barcode对分类学和生态学的影响,目前存在的问题,以及可能的研究方向.     

一株可同时降解多种高环PAHs的丝状真菌——宛氏拟青霉(Paecilomyces variotii)

采用液体培养的方法,分离纯化了丝状真菌宛氏拟青霉(Paecilomyces variotii)并研究了其对苯并[a]蒽、苯并[a]芘、苯并[b]荧蒽、苯并[k]荧蒽、茚并[1,2,3-cd]芘的降解效果.结果表明:接种处理30 d,该菌株对混合体系中5种PAHs的降解率为16.1%～24.6%,而对单一体系中的降解率为10.4%～33.3%;同时,对单一与混合体系中PAHs的降解作用存在一定差异,苯并[k]荧蒽和苯并[b]荧蒽在单一体系中降解率增大,而其他种类的则减小.本研究结果为高环多环芳烃共代谢机理研究和多环芳烃复合污染水土环境的生物修复提供了一种新的种质资源.     

肉桂油的提取及其抑菌活性研究

本文用水蒸汽蒸馏法蒸馏经微波预处理的肉桂粉得到肉桂油,并采用滤纸片法、固相扩散法、气相扩散法研究了肉桂油对6种细菌、1种酵母、4种霉菌的抑菌活性及其最低抑菌浓度(MIC)。结果表明:肉桂油经固相和气相扩散对细菌、酵母、霉菌的抑制活性均较强,并且对真菌的抑菌活性更强一些,其次是G ,对所有供试菌种的最低抑菌浓度(MIC)<63mL/L,且真菌的MIC<细菌的MIC。     

市售长叶松油和锡兰肉桂油对登革热媒蚊埃及伊蚊的灭幼效果(英文)

松油和桂皮油由于具有芳香性气味, 因而成为良好的成虫驱避剂, 但是关于它们对蚊虫的杀幼虫作用研究不多。为揭示市售的长叶松Pinus longifolia油和锡兰肉桂Cinnamomum zeylanicum油对来源于印度德里的埃及伊蚊Aedes aegypti 4龄幼虫的毒杀潜力, 我们进行了室内研究, 以幼虫死亡率及行为改变和形态改变等指标评估其杀幼虫潜力。结果表明： 两种油对埃及伊蚊4龄幼虫均具有毒杀作用, 且松油的灭幼效果优于桂皮油。松油的LC₅₀和LC₇₀ 值分别为0.33093 mg/L 和0.54476 mg/L, 而桂皮油的LC₅₀和LC₇₀ 值分别为0.63159 mg/L和0.77736。进一步观察发现, LC₉₀剂量下桂皮油的杀幼虫潜力强于松油, 其LC₉₀为1.11879 mg/L, 而松油的LC₉₀为 1.04915 mg/L。在处理的幼虫中观察到行为改变, 如兴奋、 坐立不安、 颤抖、 痉挛然后瘫痪, 说明这两种油可能对其神经肌肉系统产生了影响。显微观察处理幼虫的形态改变发现, 与对照相比, 大多数器官的外观正常, 只是肛鳃略为内收缩而引起结构畸形, 提示肛腮可能是这两种油的作用位点, 腮的功能异常引起了幼虫死亡。这两种油品可开发用作防治蚊虫的新型杀幼虫药剂。     

丛枝菌根真菌对褐土玉米氮素吸收和土壤N2O排放的影响

探究不同氮肥水平下丛枝菌根(AM)真菌对褐土玉米土壤N₂O排放和氮转化功能基因的影响,为阐明AM真菌在褐土N₂O排放中的作用和效应提供理论依据。设置氮肥用量(NⅠ:105 mg/kg;NⅡ:210 mg/kg)、AM真菌(M0:不接种AM真菌;M1:接种根内根孢囊霉(Rhizophagus intraradices);M2:接种摩西斗管囊霉(Funneliformis mosseae);M3:接种Rhizophagus intraradices + Funneliformis mosseae等比例混合)双因素盆栽试验。测定植株地上部全氮含量、土壤铵态氮、硝态氮含量和N₂O排放量,采用实时荧光定量聚合酶链式反应(PCR)法分析土壤硝化功能基因(amoA-AOA和amoA-AOB)和反硝化功能基因(nirS、nirK和nosZ)的丰度。结果表明,两种施氮水平下,接种AM真菌均可显著降低土壤N₂O排放通量和累积排放量,不同AM真菌处理下N₂O累积排放量表现为:M0>M2>M1>M3。相同AM真菌处理的土壤N₂O排放通量和累积排放量在NⅡ施氮水平高于NⅠ施氮水平;相同AM真菌处理的玉米菌根侵染率在NⅡ施氮水平低于NⅠ施氮水平。与M0相比,NⅠ条件下M1、M2和M3处理土壤铵态氮含量分别降低24.5%、20.8%和45.3%,硝态氮含量分别降低19.7%、14.9%和30.2%,植株地上部全氮含量分别增加16.3%、35.2%和59.6%;与M0相比,NⅡ条件下M1、M2和M3处理土壤铵态氮含量分别降低20.9%、24.8%和40.0%,硝态氮含量分别降低36.3%、25.6%和45.2%,植株地上部全氮含量分别增加33.2%、43.9%和95.4%。两种施氮水平下,AM真菌可显著降低土壤硝化功能基因(amoA-AOA和amoA-AOB)丰度,增加反硝化功能基因(nirS、nirK和nosZ)丰度。AM真菌与N₂O排放通量呈极显著负相关。本盆栽试验条件下,接种AM真菌均可增强两种氮肥用量玉米植株氮素吸收能力,调节硝化、反硝化相关功能基因的丰度,减少土壤N₂O气体的排放,且两种AM真菌混合处理的N₂O减排效应强于单一AM真菌接种。     

硝化抑制剂DCD、 DMPP对褐土氮总矿化速率和硝化速率的影响

采用15N库稀释-原位培养法研究了硝化抑制剂DCD、DMPP对华北盐碱性褐土氮总矿化速率和硝化速率的影响.试验在山西省运城市种植玉米的盐碱性土壤上进行,设单施尿素、尿素+DCD、尿素+DMPP 3个处理.结果表明:施肥后2周,DCD、DMPP分别使氮总矿化速率和氮总硝化速率减少了25.5％、7.3％和60.3％、59.1％,DCD对氮总矿化速率的影响显著高于DMPP,两者对氮总硝化速率的影响无显著差异;而在施肥后7周,不同硝化抑制剂对氮总硝化速率的影响存在差异.施肥后2周,3个处理的土壤氮总矿化速率和硝化速率分别是施肥前的7.2 ～10.0倍和5.5 ～21.5倍;NH4+和NO3-消耗速率分别是施肥前的9.1 ～12.2倍和5.1 ～8.4倍,这是由氮肥对土壤的激发效应所致.硝化抑制剂使氮肥更多地以NH4+形式保持在土壤中,减少了NO3-的积累.土壤氮总矿化速率和总硝化速率受硝化抑制剂的抑制是N2O减排的主要原因.