21种植物提取物对玉米象的生物活性

为了筛选对粮库安全的植物源杀虫剂,研究了21种植物的4种溶剂（无水乙醇、丙酮、乙酸乙酯和石油醚）提取物对玉米象Sitophilus zeamais Motschulsky的驱避和触杀作用。结果表明,高良姜Alpinia officinarum石油醚提取物、黄姜Curcuma longa丙酮提取物和山鸡椒Litsea cubeba石油醚提取物对玉米象成虫的驱避作用显著,处理60 h平均驱避等级均达到Ⅴ级,平均驱避率分别为80.02%、80.60%和81.70%。在21种植物中,石菖蒲Acorus gramineus和巴豆Croton tiglium的4种溶剂提取物均对玉米象成虫的触杀作用明显,7.86 mg/cm²的剂量处理4天后的校正死亡率均达到90%以上。     

Effectiveness of AV-1011® to reduce damage to drill-planted rice from blackbirds

We determined efficacy of AV-1011® (a 50% anthraquinone product; Arkion® Life Sciences, New Castle, Delaware) on drill-planted rice seed to reduce blackbird damage and determine residue levels of anthraquinone (AQ) in rice seeds and seedlings and in the mature rice crop under field enclosures at the University of Missouri-Delta Center farm near Portageville, Missouri. Red-winged blackbird (Agelaius phoeniceus) damage was higher for untreated than AV-1011® treated rice seedlings at assessment period 3, 15 days postplanting (F_1,141 = 15.81, P < 0.001), and at assessment period 4, 19 days postplanting (F_1,136 = 11.54, P = 0.001). Blackbird damage to AV-1011-treated seedling for assessment periods 3 and 4 was 8% and 7%, respectively, while blackbird damage to untreated seedlings during the same assessment periods was 52% and 44%. More blackbirds used untreated plots than AV-1011-treated plots during assessment periods 2–4 (F_1,17.8 = 20.02, P < 0.001). Overall concentrations of AQ on seeds averaged 5,993 µg/g or 0.59% during the test period. Concentrations of AQ in mature rice seed and plant collected at harvest averaged 1.22 µg/g and 0.10 µg/g, respectively. AV-1011 offers promise for reducing bird depredations to newly planted rice, but additional testing should be conducted to evaluate this repellent in a large-scale field setting. © 2011 The Wildlife Society.     

Anting in a Semifree-ranging Group of <Emphasis Type="Italic">Cebus apella</Emphasis>

Capuchins apply many organic materials, especially leaves, to their skin. Protection against ectoparasites is the most commonly discussed explanation for the behavior. We describe fur rubbing with carpenter ants(Camponotus rufipes) by semifree-ranging tufted capuchins(Cebus apella) in the Tietê Ecological Park, S?o Paulo, Brazil. Carpenter ants produce and secrete high concentrations of formic acid, which repels tick nymphs. Anting occurred significantly more often during months of seasonal incidence of nymphs of the tick Amblyomma cajennense, and the behavior was not related to ant-eating. We argue that anting behavior in tufted capuchins fits the hypothesis of protection against ectoparasites.     

A novel herbal product based on Piper betle and Sphaeranthus indicus essential oils: Toxicity,repellent activity and impact on detoxifying enzymes GST and CYP450 of Aedes aegypti Liston (Diptera: Culicidae)

Fresh leaves of Piper betle Linn. (Piperales: Piperaceae) and Sphaeranthus indicus Linn. (Asterales: Asteraceae), commonly known as betel leaves and East Indian globe thistle, respectively, were harvested and steam distilled for the extraction of P. betle and S. indicus crude volatile oils (Pb-CVO and Si-CVO, respectively). LC₅₀ calculated on 3^rd instar larvae of dengue mosquito Aedes aegypti Linn. (Diptera: Culicidae) was 42.17?ppm for PbSi-CVO (i.e., herbal formulation based on the EOs of P. betle and S. indicus). The larval and pupal duration were significantly longer post-treatment with 100?ppm of PbSi-CVO, if compared to control. We observed that PbSi-CVO significantly altered the detoxifying enzymes GST and CYP450 compared to the expression of control. Sub-lethal concentrations of PbSi-CVO showed strong repellent properties against dengue mosquitoes, without adverse reactions on the volunteers experiencing the repellent assays. Lastly, the adulticidal activity of PbSi-CVO was studied. Overall, our study outlined that this herbal product represents a promising candidate for the development of botanical based adulticidal agents.     

Biotransformation of monoterpenoids, (−)- and menthols, terpinolene and carvotanacetone by Aspergillus species

Four monoterpenoids, (−)- and (+)-menthols, terpinolene and carvotanacetone were biotransformed by Aspergillus niger and several related species. Aspergillus niger converted (−)-menthol to 1-, 2-, 6-, 7-, and 9-hydroxymenthols and the mosquito repellent-active 8-hydroxymenthol. On the other hand, (+)-menthol was smoothly biotransformed by A. niger to give 7-hydroxymenthol. Aspergillus cellulosae biotransformed (−)-menthol specifically to 4-hydroxymenthol. Terpinolene and (−)-carvotanacetone were converted by A. niger to two , β-unsaturated ketones, a fenchane-type compound and diastereoisomeric p-menthane-2,9-diols and 8-hydroxycarvomenthol, respectively.     

Plant-derived compounds and extracts with potential as aphid repellents

We devised a method for screening various substances for possible aphid repellency. Corn leaf aphids ( Rhopalosiphum maidis ) were released in an arena and allowed to select paired green tiles coated with petroleum jelly alone or petroleum jelly containing 1% of the substance being tested. Aphids adhering to tiles were counted 24 h later. If significantly fewer aphids landed on treated tiles, the substance was considered to have potential for repelling aphids. Fifty-five substances were tested. Most showed no activity, but several including β-citronellol, farnesol, geraniol, linalool, oils distilled from several species of Artemisia and Achillea millefolia (yarrow) oil showed some promise.     

Laboratory experiments on factors affecting oviposition site selection in Toxorhynchites amboinensis (Diptera: Culicidae), with a report on the occurrence of egg cannibalism

Laboratory experiments tested the effects of water quality and the presence of conspecific and heterospecific immatures on oviposition by Toxorhynchites amboinensis (Doleschall). The females showed a highly significant preference for oak leaf infusion water over distilled water. When twenty starved third and fourth instar Tx.amboinensis larvae were present in the water, substantially fewer eggs were counted from pots containing these conspecifics, than from controls in which no larvae were present. Numbers of eggs from pots containing starved second instar larvae did not differ significantly from controls. Observations of larval behaviour while oviposition was occurring suggested that egg numbers were reduced in containers because of egg cannibalism with third and fourth instar larvae, and not because the larvae caused a deterrent effect. Subsequent experiments confirming the occurrence of substantial egg cannibalism by third and especially fourth instar larvae are described. As with larvae, the presence of Tx.amboinensis pupae in the water had little effect on oviposition. If placed in the water 24 h prior to test, pupae very slightly enhanced its attractiveness, but if introduced immediately before test there appeared to be a slight deterrent effect. With heterospecific larvae, twenty fourth instar Ae.aegypti larvae introduced into infusion water 24 h before test rendered the water slightly attractive, while water in which Ae.aegypti larvae had been reared for 48 h proved highly repellent.     

根癌农杆菌化学受体MCP1912调节趋化响应功能的鉴定

【目的】本研究以根癌农杆菌C58为材料,鉴定其甲基趋化受体蛋白（methyl-accepting chemotaxis protein,MCP） MCP₁₉₁₂能够识别的配体,并研究该蛋白在调控根癌农杆菌趋化响应中的具体功能。【方法】通过异源表达MCP₁₉₁₂的配体结合结构域（ligand binding domain,LBD）,获得带有His标签的LBD蛋白(LBD₁₉₁₂)。利用基于荧光的热位移测定法（fluorescence-based thermal shift assay,TSA）筛选出LBD₁₉₁₂的潜在配体;通过等温滴定量热（isothermal titration calorimetry,ITC）,进一步确定筛选出的潜在配体,并测定LBD₁₉₁₂与配体结合之后的解离平衡常数K_D。利用基于同源重组的精准DNA片段删除方法,敲除根癌农杆菌C58中编码MCP₁₉₁₂的基因atu1912,获得MCP_{1 912}     

The effects of plant essential oils on escape response and mortality rate of Aedes aegypti and Anopheles minimus

The High Throughput Screening System (HITSS) has been applied in insecticide behavioral response studies with various mosquito species. In general, chemical or natural compounds can produce a range of insect responses: contact irritancy, spatial repellency, knock‐down, and toxicity. This study characterized these actions in essential oils derived from citronella, hairy basil, catnip, and vetiver in comparison to DEET and picaridin against Aedes aegypti and Anopheles minimus mosquito populations. Results indicated the two mosquito species exhibited significantly different (P<0.05) contact irritant escape responses between treatment and control for all tested compound concentrations, except with the minimum dose of picaridin (P>0.05) against Ae. aegypti. Spatial repellency responses were elicited in both mosquito species when exposed to all compounds, but the strength of the repellent response was dependent on compound and concentration. Data show that higher test concentrations had greatest toxic effects on both mosquito populations, but vetiver had no toxic effect on Ae. aegypti and picaridin did not elicit toxicity in either Ae. aegypti or An. minimus at any test concentration. Ultimately, this study demonstrates the ability of the HITSS assay to guide selection of effective plant essential oils for repelling, irritating, and killing mosquitoes.     

蛇床子提取物对几种储粮害虫的驱避和触杀效应

研究蛇床子(Cnidium monnieri(L.)Cuss.)4种溶剂无水乙醇、丙酮、乙酸乙酯、石油醚提取物对玉米象Sitophilus zeamais(Motschulsky)、谷蠹Rhizopertha dominica(Fabricius)、锯谷盗Oryzaephilus surinamensis(L.)3种储粮害虫的驱避作用和触杀作用。结果表明:蛇床子4种溶剂的提取物对3种试虫具有一定的驱避作用和触杀作用,60 h的平均驱避等级最高达到Ⅴ级,对3种试虫的触杀死亡率最高达到100%。