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以CrylAc活性毒素逐代筛选抗性粉纹夜蛾离体细胞BTI-TN-5B1抗性发展速度呈S形曲线，经56代选择后，抗性比上升至1280倍。在去除选择压力后，抗性比逐渐下降。低水平抗性细胞抗性衰退较快，而高水平抗性细胞抗性衰退较缓慢。抗性比衰退至1．5倍的细胞在复筛后抗性比恢复较快。抗性细胞对苏云金杆菌工程菌GC-91(BtGC-91)、苏云金杆菌鲇泽亚种(B.t.atoazai)和苏云金杆菌库斯塔克亚种(B．t．kurstaki)的复合毒素晶体的活性毒素都具有较高的交互抗性，但对农药无交互抗性，对杆状病毒的敏感性也没发生变化。 相似文献
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以Cry1Ac活性毒素逐代筛选抗性粉纹夜蛾离体细胞BTI-TN-5B1,抗性发展速度呈S形曲线,经56代选择后,抗性比上升至1 280倍.在去除选择压力后,抗性比逐渐下降.低水平抗性细胞抗性衰退较快,而高水平抗性细胞抗性衰退较缓慢.抗性比衰退至1.5倍的细胞在复筛后抗性比恢复较快.抗性细胞对苏云金杆菌工程菌GC-91(Bt GC-91)、苏云金杆菌鲇泽亚种(B.t.awazai)和苏云金杆菌库斯塔克亚种(B.t.kurstaki)的复合毒素晶体的活性毒素都具有较高的交互抗性,但对农药无交互抗性,对杆状病毒的敏感性也没发生变化. 相似文献
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苏云金杆菌杀虫剂新进展 总被引：1，自引：0，他引：1
苏云金杆菌杀虫剂新进展苏云金杆菌简称Ｂ．Ｔ．，是一类产晶体芽孢杆菌，属好气性蜡状芽孢杆菌群，在芽孢囊内产生晶体，有１２个血清型，１７个变种。可用于防治直翅目、鞘翅目、双翅目、膜翅目，特别是鳞翅目的多种害虫。苏云金杆菌可产生两大类毒素：内毒素（即伴孢晶... 相似文献
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小麦赤霉病菌毒素对小麦抗病突变体及其亲本细胞超微结构的影响 总被引：7，自引：1，他引：6
在小麦赤霉病菌毒素的作用下,小麦抗赤霉病突变体92k809及其亲本新克旱九内颖细胞超微结构发生了变化。随着处理时间的增长,细胞器和膜系统破坏程度加剧,但在相同处理时间内,突变体细胞的超微结构破坏程度比其亲本要轻。对赤霉病菌毒素最敏感的是线粒体,其次是叶绿体、细胞质膜和细胞核膜。本文还探讨了赤霉病菌毒素在致病过程中的作用及其致病机理。 相似文献
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研究了7种常用化学杀虫剂对苏云金杆菌芽孢及伴胞晶体的影响及作用,结果表明,常用浓度下,2.5%溴氰菊酯乳油、48%毒死蜱乳油对苏云金杆菌芽孢及伴胞晶体无影响,可与苏云金杆菌制剂事先做成混剂;4.5%高效氯氰菊酯乳油、2.5%高效氯氟氰菊酯乳油、20%灭多威和40%辛硫磷在短时期内对芽孢及伴胞晶体无明显影响,可与苏云金杆菌制剂现混现用;80%敌敌畏乳油(500倍稀释)对苏云金杆菌伴胞晶体有明显损伤作用,不宜与苏云金杆菌制剂混合使用。 相似文献
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球形芽孢杆菌（Bacillussphaericus）是一种对蚊幼虫有毒杀作用的好气芽孢杆菌。高毒力菌株在芽孢形成过程中能产生有51．4和41．9kDa蛋白组成的伴孢晶体。蚊幼虫取食芽孢／晶体混合物后,晶体蛋白被降解形成活性蛋白而结合到中肠上皮细胞的特异性结合位点上,最后导致蚊幼虫死亡;低毒力菌株和部分高毒力菌株在其营养体生长阶段可产生可溶性的100、30．5和38．5kDa的Mix毒素（Mtx1、Mtx2和Mix3）。该毒素同晶体毒素和其它杀虫毒素无同源性,其杀蚊作用机理不详。在实验室和野外长期高选择性压力下,蚊幼虫会通过中肠上皮细胞二元毒素特异性结合位点的改变而对球形芽孢杆菌产生不同水平的抗性,其抗性特性是由位于染色体上的单一隐性基因决定的。本文简述了球形芽孢杆菌的杀蚊毒素的作用方式及抗性蚊虫的抗性特性。 相似文献
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比较了粘虫和家蚕对苏云金芽孢杆菌库斯塔克亚种菌株ＨＤ┐１的伴孢晶体在幼虫中肠液中的体外活化过程。ＳＤＳ┐ＰＡＧＥ结果表明,伴孢晶体或溶解的１３０ｋＤａ原毒素在粘虫中肠液中活化后形成的毒性肽的浓度比家蚕低,原因是１３０ｋＤａ原毒素在粘虫中肠液中发生了过度降解。蛋白酶活性检测结果表明,粘虫中肠液中含有较高的蛋白酶活性。 相似文献
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本文主要介绍苏云金杆菌伴孢晶体毒素离体生物测定技术的兴起及其在国内外发展的现状。并简述了离体生测的作用机制。还对该技术在生产实践中的应用前景进行了探讨。 相似文献
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在电镜下观察发现,菜豆锈病菌侵染菜豆后,逐步对其超微结构产生影响:寄主细胞发生质壁分离;叶绿体变形;叶绿体的片层结构排列零乱;线粒体脊模糊不清,直至叶绿体解体;线粒体空泡化;少数细胞的细胞壁分解;不同细胞的细胞器堆积在一起。同时,病原菌的侵染激发了寄主抗病性的细胞学表现:供试的抗感菜豆品种都表现为在病原菌侵入位点的寄主细胞壁内侧有高电子致密物质沉积;与吸器母细胞接触的寄主细胞壁加厚以及在吸器颈周围有电子不透明物质形成。只是这3种反应在抗病品种中表现得更加强烈。此外,抗病品种中还有一些特有的抗性特征,如被侵染细胞及其相邻细胞的快速坏死,吸器母细胞侵入位点的寄主细胞壁外侧也有一种高电子致密物质沉积,抗病品种中真菌吸器周围聚集含大量线粒体的寄主细胞的细胞质,且吸器外基质比感病品种中的宽。 相似文献
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从二点委夜蛾幼虫体内首次分离到一种微孢子虫ED2013,用透射电镜观察了该微孢子虫感染二点委夜蛾幼虫后中肠的病理变化。结果发现寄主被感染后,中肠细胞微绒毛与杯状细胞的细胞质突起存在肿胀并掉落的情况;有些细胞核出现明显变形及膨大,或被挤压成长条状,细胞核内未发现微孢子虫侵入;部分线粒体略微肿胀变形,嵴的排列方向发生变化,随着感染时间延长而逐渐降解;细胞质中的粗面内质网上附着的核糖体脱落,后期感染严重阶段断裂成小段。染病后期的中肠细胞内充满微孢子虫,细胞质中的各细胞器均出现严重降解。根据研究结果并结合前人成果,认为该微孢子虫侵染二点委夜蛾的病理过程是从中肠细胞的病理变化开始并最终导致细胞破裂,逐渐扩大到寄主组织和器官,使其功能丧失,重者死亡。 相似文献
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Robert Krämer Sibylle Freytag Elmon Schmelzer 《European journal of plant pathology / European Foundation for Plant Pathology》1997,103(1):43-53
Efficient and synchronized production of infection structures of Phytophthora infestans, the causal agent of late blight of potato, was established on an artificial membrane without the host plant. Microscopic comparison of the in vitro and the in planta formed fungal structures revealed a high degree of similarity. In vitro development of infection structures enabled detailed cytological and biochemical investigations. By video microscopy the highly dynamic phenomenon of cytoplasmic migration was monitored within the living fungus. At four distinct developmental stages, hyphae, cysts, germinating cysts and appressoria, all grown in vitro, protein synthesis was analysed by comparative two-dimensional SDS-polyacrylamide gel electrophoresis. On two-dimensional gels of protein extracts of the four developmental stages a number of polypeptides were identified that showed stage-specific differences in their relative amounts. The de novo synthesis of proteins was investigated by in vivo labelling experiments. A number of polypeptides showed development-dependent expression. The majority of changes in protein synthesis occurred during germination of cysts and development of the germ tubes. In particular, at the stage of appressoria formation, the actual start of the infection process, several major polypeptides were newly synthesized. 相似文献
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The sensitivity of Venturia inaequalis to trifloxystrobin was monitored by both in vitro (spore germination) and in vivo tests (on apple seedlings). There was good correlation between the in vitro and in vivo results. Baseline sensitivity was established with 95 bulk isolates from Europe between 1995 and 1998 which showed a narrow sensitivity range-factor of up to 17 between the least and most sensitive isolates. Monitoring of populations originating from trifloxystrobin-treated and untreated orchards between 1995 and 1999 showed only sensitive isolates and no performance deficiencies were reported. Data also show that trifloxystrobin is not cross-resistant to anilinopyrimidines and triazoles, but is cross-resistant to kresoxim-methyl, another strobilurin which also inhibits the cytochrome bc1 enzyme complex at the Qo-site in the respiration chain of fungal mitochondria (QoI inhibitors). Under experimental conditions from a specific trial site in Switzerland, where trifloxystrobin has been tested since 1994, isolates containing conidia resistant to Qo inhibitors were detected in 1997 and 1999. However no obvious performance deficiencies were reported. Nevertheless these results demonstrate a risk for the development of practical resistance in V inaequalis to Qo inhibitors and therefore a need to apply resistance management principles strictly. 相似文献
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Shirin Pournourmohammadi Seyed Nasser Ostad Mohammad Hossein Ghahremani Bagher Minaie Mohammad Abdollahi 《Pesticide biochemistry and physiology》2007,88(3):346-352
Hyperglycemia is observed with exposure to organophosphorus (OP) pesticides. The aim of this study was to investigate the effects of malathion on secretion of insulin from rat pancreatic islets in vitro and in vivo. Malathion was administered through food for 4 weeks at concentrations of 100, 200, and 400 ppm. For in vivo experiment, at the end of treatment, blood sample was obtained and plasma was separated. For in vitro experiment, the treated rats were anesthetized and underwent a laparatomy. The common bile duct was cannulated and the pancreas distended by injecting of cold collagenase V using peristaltic infusion pump. Islets were then hand picked under a stereomicroscope and cultured in the presence of various doses of glucose and KCl. Malathion at doses of 200 and 400 ppm increased plasma glucose and insulin concentrations and lowered activity of erythrocyte acetylcholinesterase. The isolated islets from pretreated animals with malathion 200 and 400 ppm showed lower glucose-stimulated insulin secretion while no change was observed in the presence of KCl. Light microscopic examination revealed that malathion causes patchy degenerative changes in pancreatic islets. Combination of in vivo and in vitro findings suggests that malathion induces a kind of insulin resistance that cannot overwhelm hyperglycemia. This action of malathion is mediated through disruption of islets mitochondrial function. 相似文献
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山定子感染南京毛刺线虫后几种生理生化物质的变化 总被引：5，自引：0，他引：5
山定子(Malus baccata Borkh.)在遭到南京毛刺线虫(Trichodorus nanjingensis Liu & Chen)侵染以后,根尖组织中很多生理生化物质都发生了病态的变化。结果表明:处理和对照相比,游离脯氨酸(Pro)含量、还原糖(RC)含量、过氧化物酶(POD)活性、多酚氧化酶(PPO D)活性、苯丙氨酸解氨酶(PAL)活性和细胞壁中羟脯氨酸(Hyp)含量均有不同程度的增加,总糖含量降低;并且在侵染初期和侵染后期,各种物质的变化幅度不同,游离脯氨酸含量、还原糖含量、3种酶活性在侵染前期增加的幅度大,细胞壁中羟脯氨酸含量是侵染后期增加的幅度大,而总糖含量是侵染后期降低的幅度大。这些物质的变化趋势揭示了山定子感染南京毛刺线虫的病症生理。 相似文献
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The vitellogenesis of Paraechinophallus japonicus (Yamaguti, 1934), the first pseudophyllidean tapeworm of the family Echinophallidae studied using transmission electron microscope, is described on the basis of ultrastructural observations of specimens from the benthopelagic fish Psenopsis anomala (Temminck et Schlegel, 1844) (Perciformes: Centrolophidae). The process of vitellogenesis in P. japonicus follows the same general pattern observed in other tapeworms. Five stages of vitellocyte development have been distinguished. The first stage corresponds to immature cells containing ribosomes and mitochondria. The second stage of development is characterized by the appearance of granular endoplasmic reticulum and Golgi complexes, formation of shell globules and lipid droplets at the periphery of the cell cytoplasm. Vitellocyte of the third stage presents accumulation of shell globules and lipid droplets. During the fourth stage, shell globule clusters are formed, and lipid droplets and rosettes of alpha-glycogen are accumulated. Mature vitelline cells are characterized by a great number of lipid droplets with glycogen in the centre of the cytoplasm, whereas shell globule clusters are situated more peripherally. The interstitial tissue of vitelline follicles of P. japonicus is syncytial with long cytoplasmic projections extending between vitelline cells. The presence of a large amount of lipid droplets in the vitelline cytoplasm within the eggs of P. japonicus may be related to egg accumulation in the uterine sac. 相似文献
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During storage of potato tubers (Solanum tuberosum L., var. Bintje), important changes appear which affect respiratory control, , intensity of O2 consumption in the presence of different substrates, and NAD+ dependence, In mitochondria extracted under strictly similar conditions, from patato tubers stored at 4°C, the respiratory control (RC) maintains a value near 4 for 4 to 5 months. It then declines progressively to low values. At 20°C, a stable RC of 4 can be observed for several months, which then decreases at the end of dormancy. Then, the RC increases sharply; at this stage, are abnormally low, and, some time later, NAD+ dependence disappears. Mitochondria treated with 250 μM chlorpropham show a 50% inhibition of the electron transfer with exogenous NADH as substrate. After tuber treatment with 1% chlorpropham, sprouting is inhibited for several months. The activities of mitochondria extracted from such tubers remain unaffected by the treatment. The use of this phenylcarbamate for potato tuber treatment permits obtaining functional mitochondria from tubers after a slightly longer period of storage. 相似文献
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本文首次报导用人工饲料离体培养 玉米螟赤眼蜂从卵到成虫。饲料组成为柞蚕蛹血淋巴或柞蚕蛹整体匀浆液、蛋黄和牛奶。用此饲料作卵浆制成的人工卵,按1粒卵接6头蜂的比例接蜂,寄生率达90％以上。每一被寄生后出蜂的卵可得成蜂34—37头,其中雌性90％、展翅率95％,出蜂卵率56—63％。文中还讨论了赤眼蜂在人工卵内数最少不能化蛹的原因。 相似文献