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1.
球形芽孢杆菌(Bacillus sphaericus)LP1-G菌株在MBS培养基上能正常生长、发育,产生位于芽孢孢外膜外的伴孢晶体。其产生的41.9和51.2kD二元毒素蛋白合成于芽孢形成期,另一分子量约为49kD蛋白和二元毒素同期合成,并随着芽孢的释放而被降解。生物测定结果表明该菌株在营养体生长阶段对致倦库蚊幼虫无毒,孢子囊初期毒力较高,并在整个芽孢形成期都维持较高的毒力水平。其全发酵液对敏感和抗性库蚊幼虫都具有中等的毒杀作用,对3~4龄幼虫48h的LC_50。值分别为0.113和0.1  相似文献   

2.
球形芽孢杆菌(Bacillus sphaericus)LP1-G菌株在MBS培养基上能正常生长、发育,产生位于芽孢孢外膜外的伴孢晶体。其产生的41.9和51.2kD二元毒素蛋白合成于芽孢形成期,另一分子量约为49kD蛋白和二元毒素同期合成,并随着芽孢的释放而被降解。生物测定结果表明该菌株在营养体生长阶段对致倦库蚊幼虫无毒,孢子囊初期毒力较高,并在整个芽孢形成期都维持较高的毒力水平。其全发酵液对敏感和抗性库蚊幼虫都具有中等的毒杀作用,对3~4龄幼虫48h的LC_50。值分别为0.113和0.137mg/mL。该菌株对敏感和抗性致倦库蚊幼虫的毒杀作用可能同其产生49kD蛋白相关。  相似文献   

3.
苏云金芽孢杆菌杀虫晶体蛋白与DNA分子的相互作用   总被引:2,自引:0,他引:2  
苏云金芽孢杆菌 (Bacillusthuringiensis,简称Bt)在形成芽孢的同时能够产生伴孢晶体 ,其中含有一种或几种杀虫晶体蛋白 (ICPs,InsecticidalCrystalProteins) ,即δ 内毒素[1] 。伴孢晶体进入敏感昆虫的消化道后发生溶解并释放出 2 7~ 1 40kD的原毒素。在中肠蛋白酶的作用下 ,原毒素被激活为 2 3~ 70kD的毒性多肽[2~ 4 ] 。随后毒素与中肠刷状缘膜泡 (BBMV ,BrushBorderMembraneVesicle)上的特异受体发生结合并且在细胞膜上形成孔道 ,破坏细胞…  相似文献   

4.
对951个样品分离鉴定,有747个样品含芽孢杆菌,有菌率为78.55%.共分离得到芽孢杆菌1138株,其中苏云金杆菌(Bacillusthuringiensis,简称B.t)143株,占12.5%;球形芽孢杆菌(Bacillussphaericus,简称B.s)11株,占0.97%;其他芽孢杆菌984株,占86.40%.从芽孢杆菌中选出产生晶体、苏云金素或磷酸酯酶C(PhosphalipaseC,简称PLC)的毒素菌株168株,其中B.t占143株,B.s有5株,其他芽孢杆菌10株.在产毒素菌株中,经测定有120株菌对供试昆虫毒性达标.占77.92%.不同菌株的杀虫毒素、杀虫范围和毒力各异,认为这种差异取决于毒素和虫种两方面的特异性.  相似文献   

5.
球形芽孢杆菌C3-41是我国分离的一株对蚊幼虫有毒杀作用的高毒力菌株,对库蚊、按蚊幼虫的毒性高于2362菌株,Southern杂交证明C3-41总DNA中3.5KbHindIII片段上带有41.9和51.4kD二元毒素基因。  相似文献   

6.
新加坡分离到五株新的灭蚊球形芽孢杆菌。这些菌株都属于噬菌体8组,具有双毒素(51.4+41.9kDa)基因,位于染色体上,但缺乏一个100—kDa毒素基因。这些球孢菌组成了一个新的亚群,在噬菌体8组中仅有2株弱毒菌株已有论述,而在已知的全部高毒菌株都含有双毒素和100-kDa毒素两种基因。  相似文献   

7.
通过电转化方法将含球形芽孢杆菌(Bacillussphaericus简称B.s)二元毒素基因的重组质粒pCW2转化野生型苏云金杆菌以色列亚种(B.thuringiensissubsp.israelensis简称B.t.i),获得一株含二元毒素基因的重组菌株B+CW-1。重组菌株能表达二元毒素及δ-内毒素和CytA毒素,并形成2类位于芽孢孢外膜外的伴孢晶体。B+CW-1对伊蚊(Aedes)、按蚊(Anopheles)和抗性库蚊(Culex)的毒力明显高于B.s,同时也略高产B.t.i菌株,但其杀蚊谱和杀活性水平同B.t.i相似。未发现二元毒素同B.t.i毒素间的协同作用。  相似文献   

8.
球形芽抱杆菌C3-41菌株(Bacillussphaericus C3-41)对致倦库蚊(Culexquinquefa-sciatus)幼虫有很高毒效,对2龄和3—4龄幼虫的半致死剂量(LD50)分别为63.1和89.7芽孢/蚊幼虫。处理浓度越高,取食时间越长,蚊幼虫取食到的杀蚊活性物质量越多,死亡率越高。当蚊幼虫取食互致死剂量杀蚊活性物质后,球形芽孢杆菌在感染的活幼虫体内不增殖;但当蚊幼虫取食致死剂量杀蚊活性物质后,蚊幼死亡,球形芽抱杆菌在死蚊幼虫体内增殖明显,6天内芽抱从感染初期的1.86×102/蚊幼虫增加到1.59×106/蚊幼虫。芽抱在死蚊幼虫体内能正常荫发、生长、产孢和形成毒素。增殖的芽抱同样对致倦库蚊幼虫有较高毒力。  相似文献   

9.
球形芽孢杆菌C3-41是我国分离的一株对蚊幼虫有毒杀作用的高毒力菌株,对库蚊、按蚊幼虫的毒性高于2362菌株,Southern杂交证明C\-3\|41总DNA中35Kb HindIII片段上带有419和514kD二元毒素基因,该片段由3479个核苷酸组成,核苷酸序列同2362菌株的二元毒素基因序列完全相同。含二元毒素基因的重组质粒pCW\|1和pCW\|2能在大肠杆菌中表达产生二元毒蛋白,但表达量低,重组子杀蚊毒性低。无晶体型苏云金芽孢杆菌以色列亚种重组子在其芽孢形成中能产生以晶体形式存在的二元毒素蛋白,其全发酵液和纯化晶体蛋白的杀蚊活性与C\-3\|41相近。  相似文献   

10.
以球孢白僵菌Beauveria  bassiana和玫烟色拟青霉Paecilomyces fumosoroseus为研究对象,利用紫外线诱变芽生孢子和低水活度条件胁迫筛选,选育出突变株Bb07240、Pf01120和Pf01160,它们在低水活度(或相对湿度)下的生长和萌发均明显优于其相应的初始菌株。生物测定表明,突变株对桃蚜的毒力明显高于其初始菌株。  相似文献   

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Although the importance of the endosperm as a food store inmany angiosperm seeds is well known, its significance duringearly embryogenesis has been neglected. In many interspecifichybrids, and in some other situations, embryos do not developfully and abort. It has often been stated that this is causedby the endosperm failing to conduct sufficient nutrients tothe embryo, but seldom has it been suggested that the endospermactively controls most of the early stages of morphogenesisof the embryo. Information gleaned from a broad survey of theliterature, combined with additional evidence presented here,obtained fromSolanum incanumand interspecific hybrids, indicatethat the endosperm is dynamic and very active in regulatingearly embryo development. This requires highly integrated geneticcontrol of rapidly changing metabolism in the endosperm. Ininterspecific hybrids, lack of coordination may cause unbalancedproduction of growth regulating substances by the endospermand hence abortion of the embryo, or even unregulated productionof nucleases and proteases resulting firstly in autolysis ofthe endosperm and then digestion of the embryo. The endospermmay thus serve to detect inappropriate hybridization of speciesor ploidy levels and so prevent waste of resources by producingseeds that would result in sterile hybrids or unthrifty subsequentgenerations. This discriminatory function of the endosperm hasdiminished during evolution and domestication of the crop plantSolanummelongenaL.Copyright 1998 Annals of Botany Company Solanum, embryo morphogenesis, endosperm, hybrid, seed development.  相似文献   

13.
Aegidius 《CMAJ》1972,107(3):185
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For most organisms oxygen is essential fo life. When oxygen levels drop below those required to maintain the minimum physiological oxygen requirement of an organism or tissue it is termed hypoxia. To counter act possible deleterious effects of such a state, an immediate molecular response is initiated causing adaptation responses aimed at cell survival. This response is mediated by the hypoxia-inducible factor-1 (HIF-1), which is a heterodimer consisting of an alpha- and a beta-subunit. HIF-1 alpha protein is stabilized under hypoxic conditions and therefore confers selectivity to this response. Hypoxia is characteristic of tumors, mainly because of impaired blood supply resulting from abnormal growth. Over the past few years enormous progress has been made in the attempt to understand how the activation of the physiological response to hypoxia influences neoplastic growth. In this review some aspects of HIF-1 pathway activation in tumors and the consequences for pathophysiology and treatment of neoplasia are discussed.  相似文献   

16.
Pragmatic Women and Body Politics. Margaret Lock and Patricia A. Kaufert. eds. Cambridge, UK: Cambridge University Press, 1998. xii +364 pp.
Maternities and Modernities: Colonial and Postcolonial Experiences in Asia and the Pacific. Kalpana Ram and Margaret Jolly. eds. Cambridge, UK: Cambridge University Press, 1998. xiv. 305 pp.  相似文献   

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《环境昆虫学报》2014,(5):790-804
综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生(宾主共栖和异种共栖)、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌(原生动物、细菌、真菌和放线菌)和外生菌(蚁巢伞菌等)间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用(如纤维素酶)及今后研究物种间的协同进化提供了基础资料。  相似文献   

20.
Studies of human constitution and mental features are traditionally among the main concepts of anthropological research. In this research, we attempted to discover connections between morphological and constitutional features and self-esteem in children and adolescents. Such a connection was discovered in some studied age groups. The obtained results could serve as a basis for further studies in this field.  相似文献   

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