IPM program development for an invasive pest: coordination, outreach and evaluation

BACKGROUND: Spotted wing drosophila (SWD), Drosophila suzukii Matsumura, was found along the west coast of the United States, beginning in 2008 and 2009, infesting a wide variety of small and stone fruit crops. This pest is a serious economic threat, as noted in its native range (Asia), because it lays eggs within ripening fruit before harvest, leading to crop loss. The aim of this paper is to describe the process in order to create collaboration, communication routes and evaluation methods in response to a new invasive pest. RESULTS: Funding was secured and a program (SWD*IPM) was quickly developed to address social, economic and biological components. Communication routes were outlined, and a stakeholder advisory panel was established to guide program objectives. A central website was created to host up‐to‐date information. An online monitoring and mapping program for D. suzukii in Oregon fruit‐growing regions illustrated the range, distribution and seasonal abundance of the pest. In addition, a program for backyard fruit growers was initiated to examine citizen scientists' roles in managing D. suzukii infestations in the urban setting. A monitoring kit, laminated educational cards, dry fly mounts and quick‐time videos were some of the tools used to educate growers. First‐year challenges for dealing with a new pest are discussed. CONCLUSION: The discovery and subsequent response to an exotic pest is information intensive and requires a well‐planned, coordinated Extension and evaluation effort. Copyright © 2011 Society of Chemical Industry     

Laboratory survival of Drosophila suzukii under simulated winter conditions of the Pacific Northwest and seasonal field trapping in five primary regions of small and stone fruit production in the United States

BACKGROUND: Drosophila suzukii was first found in Oregon in August 2009. The threat of this pest to regional small and stone fruit production industries led to investigations on its overwintering capabilities in fruit‐growing regions in the Pacific Northwest. Knowledge of its cold tolerance will help in the development of computer models to forecast seasonal population growth and decline. RESULTS: Of 1500 adults or pupae, 22 (1.4%) individuals survived the 84 day experimental chilling period. Most (86%) of the survivors were subjected to 10 °C temperature treatments. Survival decreased significantly at lower temperature treatments. Freezing temporarily increased the mortality rate but did not significantly affect overall mortality over the trial period. Flies that emerged from pupae are estimated to survive for up to 103–105 days at 10 °C and for shorter periods at lower temperatures. Field trapping in five fruit production areas has demonstrated overwintering survival in California and Oregon, but lower survival is predicted in Eastern Washington and Michigan. CONCLUSION: The experiments reported here indicate that long‐term survival of D. suzukii is unlikely at temperatures below 10 °C. Field data from five climatic regions indicated extended low initial D. suzukii field presence in 2010 in all regions except California, where field presence was recorded earlier. Copyright © 2011 Society of Chemical Industry     

海带多糖的抗衰老作用及其机理的研究

以果蝇(Drosophila melanogaster)作为试验动物,探讨了海带多糖(Laminaria japonicapolysaccharide,LJP)延缓衰老的作用及其机理。试验将未交配的果蝇雌雄分开并随机分成4组,每组100只,用含不同浓度海带多糖的培养基喂养,培养基中所含海带多糖的浓度分别为0(对照组)、0.25%、0.50%、1.00%。用果蝇寿命试验检测其抗衰老作用,分别使用邻苯三酚自氧化法、钼酸铵比色法、硫代巴比妥酸(TBA)法测定果蝇体内超氧化物岐化酶(SOD)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量。利用统计学软件SAS v6.12对试验数据进行分析。结果表明:培养基中添加海带多糖能延长果蝇平均寿命,寿命延长的百分率与喂食果蝇的海带多糖浓度有一定的量效关系,培养基中海带多糖浓度为0.25%、0.50%、1.00%时,与对照组相比,雌果蝇寿命延长百分率分别为5.20%、6.20%、9.20%,雄果蝇寿命延长百分率分别为4.60%、5.00%、6.00%;饲喂海带多糖后果蝇体内的SOD、CAT活性提高,与对照组相比,海带多糖添加量为0.50%和1.00%时,雌性果蝇SOD、CAT活性提高量达到显著水平(P<0.05),MDA降低量达到显著水平(P<0.05);海带多糖添加量为1.00%时,雄性果蝇SOD与CAT活性提高量达到显著水平(P<0.05),MDA含量降低。提示提高生物体内抗氧化酶活力,降低衰老物质前体的含量可能是海带多糖抗衰老的途径之一。     

黑腹果蝇紫眼卷翅遗传规律的研究

为研究本实验室在紫眼野生型黑腹果蝇中发现的卷翅突变体遗传规律和分子基础,通过观察紫眼卷翅与野生型、紫眼卷翅与红眼卷翅后代各性状的表现规律,设计14对引物检测了syt基因与Alp23B基因间DNA多态性。结果表明:1)在紫眼卷翅与野生型杂交的F1中,卷翅与野生型的比例为1∶1;2)紫眼卷翅与野生型杂交F1代卷翅个体自交的F2中,紫眼与红眼、卷翅与野生型正常翅2对性状符合孟德尔自由分离与组合定律;3)紫眼卷翅与红眼卷翅杂交的F1中,卷翅与野生型的比例为2∶1;4)2种卷翅品系中在syt与Alp23B之间的基因组区域存在1个多态位点;2种卷翅个体均为AB型,而野生型个体为无缺失的AA型;紫眼卷翅与红眼卷翅杂交F1中卷翅个体全为AB型。紫眼卷翅突变体为显性杂合子,平衡致死系;紫眼基因与卷翅基因不连锁;2个卷翅基因为等位基因,相互间不能互补,杂合状态下致死。     

乌鸡黑色素对果蝇的紫外辐射保护作用

对黄体果蝇进行紫外辐射处理后,在含0.02或0.2mg/mL乌鸡黑色素的培养基中培养,通过测定果蝇寿命、繁殖力和SOD比活性来分析黑色素的紫外辐射保护作用。结果显示:果蝇在5min紫外辐射 0.2mg/mL黑色素组的下四分位(14.5±1.3)d、上四分位寿命(23.5±2.1)d以及平均寿命(15.7±7.1)d显著(P<0.05)高于5 min紫外辐射组(8.0±1.4)、(16.0±3.3)和(13.5±6.4)d。每对亲本果蝇在2min紫外辐射 0.2mg/mL黑色素组繁殖子代(50.0±11.4)只比2min紫外辐射组提高了156.4%(P<0.05)。另外,黑色素可能对辐射处理果蝇体内SOD比活性有保护作用,果蝇在5min紫外辐射 0.02mg/mL黑色素组和5min紫外辐射 0.2mg/mL黑色素组的SOD比活性((209.1±13.1)和(213.25±7.7)μmol/(mg.min))高于5min紫外辐射组((204.2±11.5)μmol/(mg.min)),但差异均不显著。本试验发现乌鸡黑色素能够延长辐射处理果蝇的寿命,提高繁殖力,对其SOD活性可能也具有保护作用。上述作用或许与黑色素清除自由基的特性有关,同时,2min紫外辐射 0.2mg/mL黑色素组高繁殖力的原因可能还与黑色素对果蝇生殖细胞的保护有关。     

果蝇凋亡抑制蛋白研究进展

介绍果蝇凋亡抑制蛋白的种类、结构特征、作用机制、生物学特性以及凋亡蛋白抑制剂最近的一些研究进展。     

牛、果蝇DHX36解旋酶的表达纯化及活性比较

【目的】探索牛和果蝇DHX36解旋酶的表达纯化条件及底物结合活性,为深入研究DEAH-box解旋酶提供理论参考。【方法】以较高等动物牛(Bos taurus)和较低等动物黑腹果蝇(Drosophila melanogaster)RNA解旋酶BtDHX36和DmDHX36为研究对象,首先,构建重组表达载体pET15b-sumo-BtDHX36和pET15b-sumo-DmDHX36,将2种质粒分别转入表达菌株BL21(DE3)中,诱导表达2种目的蛋白,利用Ni-NTA层析柱、HisTrap SP HP柱纯化得到目的蛋白。然后,采用荧光各向异性法(FA)研究溶液和温度条件对2种蛋白底物结合活性的影响,以及二者的底物结合偏好性。最后利用快速停流-荧光共振能量转移(FRET)技术对2种DHX36的双链底物解旋活性进行比较。【结果】获得了纯度大于95%的全长BtDHX36和DmDHX36蛋白,2种DHX36解旋酶的最佳底物结合条件为:20 mmol/L Tris-HCl (pH 7.5)、50 mmol/L NaCl、2 mmol/L MgCl_2、反应温度37℃。在此条件下,2种同源DHX36均可结合多种类型核酸底物(ssRNA、ssDNA、parallel G4、anti-parallel G4),且BtDHX36结合平行结构G4底物(parallel G4)的倾向更明显,DmDHX36无此趋势;2种DHX36解旋酶结合不同长度ssDNA的能力不同,BtDHX36更倾向于结合较长的单链DNA底物,而DmDHX36更倾向于结合较短的单链DNA底物;二者均能高效解旋dsRNA和dsDNA底物,DmDHX36更倾向于解旋dsDNA,而BtDHX36无明显倾向性。【结论】成功表达并纯化了BtDHX36和DmDHX36蛋白,确定了其最适结合条件,比较了2种DHX36解旋酶对不同底物的结合及解旋偏好。     

Comparison of the activity of non‐steroidal ecdysone agonists between dipteran and lepidopteran insects,using cell‐based EcR reporter assays

BACKGROUND: Diacylhydrazine (DAH) analogues have been developed successfully as a new group of insect growth regulators, called ecdysone agonists or moulting accelerating compounds. These DAHs have been shown to manifest their toxicity via interaction with the ecdysone receptor (EcR) in susceptible insects, as does the natural insect moulting hormone 20‐hydroxyecdysone (20E). A notable feature is their high activity and specificity, particularly against lepidopteran insects, raising the question as to whether non‐lepidopteran‐specific analogues can be isolated. However, for the discovery of ecdysone agonists that target other important insect groups such as Diptera, efficient screening systems that are based on the activation of the EcR are needed. RESULTS: In this study, a dipteran‐specific reporter‐based screening system with transfected S2 cells of Drosophila melanogaster Meig. was developed in order to discover and evaluate compounds that have ecdysone agonistic or antagonistic activity. A library of non‐steroidal ecdysone agonists containing different mother structures with DAH and other related analogues such as acylaminoketone (AAK) and tetrahydroquinoline (THQ) was tested. None of the compounds tested was as active as 20E. This is in contrast to the very high activity of several DAH and AAK congeners in lepidopteran cells (Bombyx mori L.‐derived Bm5 cells). The latter agrees with a successful docking of a DAH, tebufenozide, in the binding pocket of the lepidopteran EcR (B. mori), while this was not the case with the dipteran EcR (D. melanogaster). Of note was the identification of two THQ compounds with activity in S2 but not in Bm5 cells. Although marked differences in activity exist with respect to the activation of EcR between dipterans and lepidopterans, there exists a positive correlation (R = 0.724) between the pLC₅₀ values in S2 and Bm5 cells. In addition, it was found through protein modelling that a second lobe was present in the ligand‐binding pocket of lepidopteran BmEcR but was lacking in the dipteran DmEcR protein, suggesting that this difference in structure of the binding pocket is a major factor for preferential activation of the lepidopteran over the dipteran receptors by DAH ligands. CONCLUSIONS: The present study confirmed the marked specificity of DAH and AAK analogues towards EcRs from lepidopteran insects. THQ compounds did not show this specificity, indicating that dipteran‐specific ecdysone‐agonist‐based insecticides based on the THQ mother structure can be developed. The differences in activity of ecdysone agonists in dipteran and lepidopteran ecdysone‐reporter‐based screening systems are discussed. Copyright © 2010 Society of Chemical Industry