排序方式： 共有11条查询结果，搜索用时 31 毫秒
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杆状病毒(Baculovirus)是昆虫及某些甲壳类动物的专性病原体,昆虫杆状病毒杀虫剂是公认的一类无公害的生物农药,联合国世界卫生组织(WHO)和粮农组织(FAO)早已推荐用于农作物害虫生物防治。但是,杆状病毒都有一个共同的缺点,就是杀死害虫时间太长(一般室内需要5—7天,田间需要时间更长)。由于这一缺点,使杆状病毒杀虫剂的商品生产和推广应用受到很大限制,甚至停滞不前。 本研究通过人工合成一种对昆虫专性的蝎子Androctonus anstralis神经毒素AaIT的编 相似文献
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Oren Froy Noam Zilberberg Nor Chejanovsky Jacob Anglister Erwann Loret Boaz Shaanan Dalia Gordon Michael Gurevitz 《Pest management science》2000,56(5):472-474
Continued use of non‐specific chemical insecticides poses potential risks to the environment and to human health resulting from non‐target toxicity and increased insect resistance to these agents. Scorpions produce anti‐insect selective polypeptide toxins that bind to and modulate voltage‐sensitive ion channels in excitable tissues, thus offering alternative, environmentally safer means for insect pest control. Despite this potential, little is known about their structural elements dictating anti‐insect preference, which may be useful for the design of selective insecticides. We used a bacterial system for expression and genetic dissection of two pharmacologically distinct scorpion toxins: alpha and excitatory. By exploiting a multi‐disciplinary approach consisting of mutagenesis, protein chemistry, electrophysiology, binding and toxicity assays, and structural studies, we elucidated the bioactive surface of two anti‐insect toxins, LqhαIT and Bj‐xtrIT. In both polypeptides the bioactive surface is composed of residues surrounding the C‐terminal region. In addition, a direct, immediate approach in using the toxin genes was demonstrated by engineering baculoviruses with cDNAs encoding LqhIT2 (depressant toxin), and LqhIT1 (excitatory toxin) resulting in viral vectors with significantly improved insecticidal efficacy. © 2000 Society of Chemical Industry 相似文献
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Dalia Gordon 《Pest management science》1999,55(10):1027-1029
Sodium channels have been a major target for the development of insecticides such as synthetic pyrethroids. However, insecticides currently available induce resistance and present limited selectivity to insect pests. Molecular and biochemical studies, as well as binding experiments using radiolabelled neurotoxins, have shown that sodium channels expressed in various insect orders must be structurally and pharmacologically different. At least three groups of peptide neurotoxins derived from scorpion venom are highly active on insects and very weakly or practically inactive on mammals. It is proposed that various insecticides are examined for possible cooperative interactions with the peptide toxins highly active on insects, and pairs of ligands are identified that will increase the selectivity not only between mammals and insects but also between different pest and non-pest insects. This is feasible on the basis of the differential allosteric modulations observed between LqhαIT, an α-toxin highly active on insects, and brevetoxin on locust versus cockroach and rat brain sodium channels. Moreover, combination of LqhαIT with the pyrethroid deltamethrin increased the binding of [125I] LqhαIT by more than 1.8-fold, and the combined presence of brevetoxin further increased the binding. Such allosteric modulation may provide a new approach to increase the selective activity of pesticides on target organisms by simultaneous application of allosterically interacting drugs, designed on the basis of the selective peptide toxins. 相似文献
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东亚钳蝎在33℃和37℃的栖息分布数量明显多于其它几种温度(12-50℃)(P<0.01).40℃以上时,蝎子不栖息.东亚钳蝎具有趋触性,容器角落栖息的数量多于平面(P<0.01).相对湿度为60%时,栖息数量最多;与其它几种湿度相比,差异极显著(P<0.01).蝎子在光照度为70 1x 时,仍选择黑暗处躺藏(P<0.01). 相似文献
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Maria Stankiewicz Franoise Grolleau Herv Rochat Eliahu Zlotkin Marcel Pelhate Bruno Lapied 《Pest management science》1999,55(10):1021-1026
The effects of an anti-insect scorpion alpha toxin, LqhαIT, isolated from the venom of the Israeli scorpion Leiurus quinquestriatus hebraeus was studied on isolated adult dorsal unpaired median (DUM) neurones isolated from the cockroach Periplaneta americana terminal abdominal ganglion. Using the cell-attached patch-clamp configuration, a new type of sodium channel, called background sodium channel (bNa), was recently characterized. At −50 mV, the channel activity was observed as unclustered brief single openings. For hyperpolarized steady-state holding potential (−100 mV) the patches contained large unitary current steps, appearing generally in bursts. The open probability (Po) calculated at −50 mV was low (0.008 (± 0.004), n = 5) and displayed a typical bell-shaped voltage dependence. LqhαIT (10−8 M ) altered the bNa activity in a time-dependent manner. At −50 mV the channel activity appeared in bursts. Po calculated at −50 mV was about 20 times greater than Po calculated in controls and also showed bell-shaped voltage dependence. At 10−7 M , LqhαIT induced longer silent periods interrupted by bursts of increased channel activity. Whole-cell recordings revealed that 10−7 M LqhαIT transformed regular beating DUM neurone pacemaker activity into a rhythmic bursting. In this paper we demonstrate, for the first time, that bNa is a new target for anti-insect scorpion toxin. © 1999 Society of Chemical Industry 相似文献
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东亚钳蝎神经毒素基因BmKCT的克隆与表达 总被引：3，自引：0，他引：3
从蝎毒腺中提取总RNA,通过RT-PCR得到东亚钳蝎神经毒素BmKCT的cDNA,将其连接到pUCm-T载体中。序列分析表明,该基因开放阅读框架编码59个氨基酸残基,其中24个为信号肽,其余35个为成熟肽,与Genebank上登录的相同。将蝎神经毒素cDNA再经PCR扩增除去信号肽序列,克隆到pTrcHisA表达载体中,转化大肠杆菌BL21(DE3),经IPTG诱导可高效表达分子质量为10ku左右的融合蛋白。表达产物约占菌体总蛋白的25%。 相似文献
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