Larvicidal and oviposition‐altering activity of monoterpenoids,trans‐anithole and rosemary oil to the yellow fever mosquito Aedes aegypti (Diptera: Culicidae)

BACKGROUND: Aedes aegypti L. is the major vector of dengue fever and dengue hemorrhagic fever. In an effort to find effective tools for control programs to reduce mosquito populations, the authors assessed the acute toxicities of 14 monoterpenoids, trans‐anithole and the essential oil of rosemary against different larval stages of Ae. aegypti. The potential for piperonyl butoxide (PBO) to act as a synergist for these compounds to increase larvicidal activity was also examined, and the oviposition response of gravid Ae. aegypti females to substrates containing these compounds was evaluated in behavioral bioassays. RESULTS: Pulegone, thymol, eugenol, trans‐anithole, rosemary oil and citronellal showed high larvicidal activity against all larval stages of Ae. aegypti (LC₅₀ values 10.3–40.8 mg L^?1). The addition of PBO significantly increased the larvicidal activity of all test compounds (3–250‐fold). Eugenol, citronellal, thymol, pulegone, rosemary oil and cymene showed oviposition deterrent and/or repellent activities, while the presence of borneol, camphor and β‐pinene increased the number of eggs laid in test containers. CONCLUSIONS: This study quantified the lethal and sublethal effects of several phytochemical compounds against all larval stages of Aedes aegypti, providing information that ultimately may have potential in mosquito control programs through acute toxicity and/or the ability to alter reproductive behaviors. Copyright © 2008 Society of Chemical Industry     

ABA处理对不同柑橘种质汁胞中挥发性物质的影响

为揭示柑橘汁胞挥发性物质代谢谱与ABA含量变化的关系,采用100μmol/L ABA处理3对有籽/无籽宽皮柑橘、柚和甜橙共6个种质的柑橘果实的汁胞并进行离体培养,室温培养10 d后进行GC-MS分析。结果显示:ABA处理对华农红柚汁胞中倍半萜类物质代谢的影响具有双重效应,δ-榄香烯、β-荜澄茄油烯、β-榄香烯、β-衣兰烯的含量显著高于对照,而榄香烯异构体和石竹烯的含量显著降低;纽荷尔脐橙处理汁胞中β-可巴烯和表荜澄茄醇等倍半萜烯及其醇化物含量显著降低至低于检测限;ABA处理对国庆1号温州蜜柑汁胞中单萜和倍半萜物质含量均有显著影响,新生成β-月桂烯、γ-萜品烯、吉马烯D和(2Z,5Z)-2,5-十五碳二烯-1-醇,而D-柠檬烯及β-榄香烯含量提升10倍以上;ABA处理后无籽琯溪蜜柚汁胞中的β-月桂烯和二氢-3-亚甲基-2,5-呋喃二酮显著降低;ABA处理对华农本地早和早金甜橙汁胞中的挥发性物质代谢谱没有显著影响。结果表明,ABA处理可以影响柑橘汁胞中挥发性物质尤其是倍半萜和单萜类物质的代谢谱变化,对果实香气品质的影响因种质而异。     

Corneal ulceration in a dog following exposure to the defensive spray of a walkingstick insect (Anisomorpha spp.)

Objective – To describe a case of corneal ulceration in a dog resulting from ocular exposure to the defensive spray of a walkingstick insect (Anisomorpha spp.). Case Summary – A 4‐year‐old, male Chihuahua in southeastern Louisiana presented to an emergency veterinary hospital approximately 20 hours after it was witnessed to have come in close proximity to a walkingstick insect. Within seconds of approaching the insect, the dog yelped, jumped backwards and developed lacrimation, blepharospasm, and periocular swelling of the left eye. Upon presentation, the dog was found to have blepharospasms and miosis of the left eye. Fluorescein stain was applied to the affected eye and diffuse corneal uptake of stain was noted. A diffuse superficial corneal ulceration was diagnosed and treated supportively with ocular flushing, topical antibiotics, ocular lubrication, and a 1% solution of ocular atropine, as well as systemic nonsteroidal anti‐inflammatory agents. Clinical signs resolved 10 days after injury. New or Unique Information Provided – While most species of walkingstick insects are considered harmless, certain species in the southeastern United States have the ability to spray defensive venom at their predators. Upon ocular exposure to the venom, the victim may experience intense pain followed by blurred vision, conjunctivitis, keratitis, and corneal ulceration. To date, there is only 1 previous reported case of ocular exposure to walkingstick venom in a dog although both children and animals may be at higher risk for ocular exposure due to their curious nature and proximity in size to the insect. Superficial corneal and conjunctival damage can occur following direct exposure to the defensive chemical spray of the Northern and Southern Twostriped walkingstick insects found in the southeastern United States and may be considered a differential diagnosis in cases involving diffuse corneal ulceration.     

The relationship between the chemical composition of three essential oils and their insecticidal activity against Acanthoscelides obtectus (Say)

The chemical composition of the essential oils isolated from various parts of three Greek aromatic plants (Lavandula hybrida Rev, Rosmarinus officinalis L and Eucalyptus globulus Labill) collected at different seasons was determined by GC/MS analysis. The insecticidal action of these oils and of their main constituents on Acanthoscelides obtectus (Say) adults was evaluated and their LC50 values were estimated. All essential oils tested exhibited strong activity against A. obtectus adults, with varying LC50 values depending on insect sex and the composition of the essential oils. A correlation between total oxygenated monoterpenoid content and activity was observed, with oxygenated compounds exhibiting higher activity than hydrocarbons. Among the main constituents, only linalyl and terpinyl acetate were not active against A. obtectus, while all the others exhibited insecticidal activity against both male and female adults, with LC50 values ranging from 0.8 to 47.1 mg litre(-1) air. An attempt to correlate the insecticidal activity to the monoterpenoid's structure is presented, and the difference in sensitivity between male and female individuals is also explored.     

New Monoterpenoids and Polyketides from the Deep-Sea Sediment-Derived Fungus Aspergillus sydowii MCCC 3A00324

Chemical study of the secondary metabolites of a deep-sea-derived fungus Aspergillus sydowii MCCC 3A00324 led to the isolation of eleven compounds (1–11), including one novel (1) and one new (2) osmane-related monoterpenoids and two undescribed polyketides (3 and 4). The structures of the metabolites were determined by comprehensive analyses of the NMR and HRESIMS spectra, in association with quantum chemical calculations of the ¹³C NMR, ECD, and specific rotation data for the configurational assignment. Compound 1 possessed a novel monoterpenoid skeleton, biogenetically probably derived from the osmane-type monoperpenoid after the cyclopentane ring cleavage and oxidation reactions. Additionally, compound 3 was the first example of the α-pyrone derivatives bearing two phenyl units at C-3 and C-5, respectively. The anti-inflammatory activities of 1–11 were tested. As a result, compound 6 showed potent inhibitory nitric oxide production in lipopolysaccharide (LPS)-activated BV-2 microglia cells with an inhibition rate of 94.4% at the concentration of 10 µM. In addition, a plausible biosynthetic pathway for 1 and 2 was also proposed.     

化感水稻苗期茎叶组织中萜类物质检测和抑草活性分析

采用稻稗抑草圈土壤盆栽种植方法,微波萃取和气质联用色谱技术测定苗期强化感水稻PI312777与非化感水稻Lemont的茎、叶中萜种类及总萜、单萜、含氧单萜浓度,并进行比较分析.根据物质分析结果,进一步考察含氧萜类对稗草的抑制能力.结果表明:化感水稻PI312777显著抑制其周围稗草的生长,且其苗期茎叶中总萜、单萜以及含氧单萜含量均高于非化感水稻Lemont.验证结果表明,所选择的7种含氧单萜的混合溶液对稗草的株高和干重的抑制作用随着浓度的增高而升高,且低浓度的含氧单萜混合溶液对常规水稻Ⅱ优航无危害作用,因此化感水稻苗期自然分泌的含氧单萜物质是一种潜在的生态安全除草剂.