Bacillus thuringiensis is a Gram-positive bacterium that is pathogenic towards a range of insect and nematode species. This is largely mediated through the production of crystal (cry) toxin proteins, which vary among B. thuringiensis strains and enable the infection of particular hosts. Because of the insecticidal activities of the cry toxins, B. thuringiensis has been used widely as a biopesticide, and there is a great deal of interest to understand further its pathogenic properties and how host resistance may evolve.. Strains of B. thuringiensis vary in their amenability to genetic manipulation, and acrystalliferous strains may have higher transformation frequencies than do crystal-producing strains (1). B. thuringiensis strain 407 was isolated as a lepidopteran-active strain, and an acrystalliferous derivative, 407 Cry-, was produced through culturing at a high temperature (2). The 407 Cry- strain can be transformed easily and it can be used to perform targeted gene knockouts; therefore, the ...
The lepidopteran-specific P1 delta-endotoxin of Bacillus thuringiensis var. kurstaki HD-1 was activated in vitro using insect gut proteases and found to be highly specific for the lepidopteran cell line Choristoneura fumiferana CF1 among a wide range of lepidopteran and dipteran cell lines tested. The toxicity of P1 against CF1 cells is inhibited by N-acetylgalactosamine (GalNAc), and the lectins soybean agglutinin (SBA) and wheat-germ agglutinin. Protein blotting was used to identify a glycoprotein of 146 X 10(3) Mr in the plasma membrane of CF1 cells, capable of binding both the toxin and SBA, which is specific for GalNAc. This glycoprotein was labelled using galactose oxidase and sodium boro-[3H]hydride and solubilized in Triton X-100 before partial purification by affinity chromatography on SBA-agarose. We propose that this glycoprotein is a good candidate for the cellular receptor of the lepidopteran-specific P1 delta-endotoxin of B. thuringiensis var. kurstaki HD-1. ...
The accessory protein P20 from Bacillus thuringiensis israelensis has been defined as an important molecular chaperone for forming crystal Cyt1Aa, and enhancing Cry11Aa and Cry4Aa expression. To investigate its putative role in Cry4Ba delta-endotoxin production and toxicity, a p20 gene was cloned and introduced into B. thuringiensis recombinant strain expressing cry4Ba type gene (cry4BLB). The delta-endotoxin synthesis was enhanced by 262%. The generated inclusions were assayed against third instar larvae of Aedes aegypti. The combination of P20 protein with Cry4BLB delta-endotoxin led to a stable mortality rate of 25% with doses ranging from 0.2 mg l−1 to 0.6 mg l−1. Cry4BLB crystals produced in the presence of P20 were much less soluble than those produced by the control strain lacking P20 at pH lower than or equal to 10.5. The observed toxicity perturbation correlates with a decrease of Cry4BLB inclusions solubility. The presence of P20 protein has affected Cry4BLB crystallization and ...
a) For the purposes of this section the microbial insecticide for which exemption from the requirement of a tolerance is being established shall have the following specifications: (1) The microorganism shall be an authentic strain of Bacillus thuringiensis Berliner conforming to the morphological and biochemical characteristics of Bacillus thuringiensis as described in Bergeys Manual of Determinative Bacteriology, Eighth Edition. (2) Spore preparations of Bacillus thuringiensis Berliner shall be produced by pure culture fermentation procedures with adequate control measures during production to detect any changes from the characteristics of the parent strain or contamination by other microorganisms. (3) Each lot of spore preparation, prior to the addition of other materials, shall be tested by subcutaneous injection of at least 1 million spores into each of five laboratory test mice weighing 17 grams to 23 grams. Such test shall show no evidence of infection or injury in the test animals when ...
TY - JOUR. T1 - Two different Bacillus thuringiensis toxin genes confer resistance to beet armyworm (Spodoptera exigua Hübner) in transgenic Bt-shallots (Allium cepa L.). AU - Zheng Sijun, S.J.. AU - Henken, B.. AU - de Maagd, R.A.. AU - Purwito, A.. AU - Krens, F.A.. AU - Kik, C.. N1 - 2680. PY - 2005. Y1 - 2005. N2 - Agrobacterium-mediated genetic transformation was applied to produce beet armyworm (Spodoptera exigua Hübner) resistant tropical shallots (Allium cepa L. group Aggregatum). A cry1Ca or a H04 hybrid gene from Bacillus thuringiensis, driven by the chrysanthemum ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (Rubisco SSU) promoter, along with the hygromycin phosphotransferase gene (hpt) driven by the CaMV 35S promoter, was employed for genetic transformation. An average transformation frequency of 3.68% was obtained from two shallot cultivars, Tropix and Kuning. After transfer of the in vitro plants to the greenhouse 69% of the cry1Ca and 39% of the H04 transgenic ...
Bacillus thuringiensis (Bt) genellikle biyolojik pestisit olarak kullanılan, Gram-pozitif, toprakta yaşayan bir bakteridir.[1] B. thuringiensis çeşitli güve ve kelebek türlerinin tırtıllarının bağırsaklarında, yaprak yüzeylerinda, sucul ortamlarda, hayvan dışkısında, böcek popülasyonunun yoğun olduğu ortamlarda, un değirmenleri ve tahıl depolama tesislerinde doğal olarak bulunmaktadır. Sporlanma sırasında, birçok Bacillus thuringiensis suşunun δ-endotoksinleri denilen kristal proteinleri (proteinli inklüzyonlar) üreterek böcekleri öldürdüğü görülmüş bu da böcek öldürücü maddeler olarak kullanımına yol açmıştır. Birçok kristal üreten Bacillus thuringiensis suşu olsa da hepsinin böcek öldürücü özellikleri yoktur. ...
The present invention provides an isolated and purified protein derived from Bacillus thuringiensis subspecies thuringiensis, having a molecular weight of approximately 20 kDa of SDS-PAGE, said protei
TY - JOUR. T1 - Bacillus thuringiensis Cry1Ac protoxin is a potent systemic and mucosal adjuvant. AU - Vazquez-Padron, Roberto I. AU - Moreno-Fierros, L.. AU - Neri-Bazán, L.. AU - De La Riva, G. A.. AU - López-Revilla, Rubén. PY - 1999/7/5. Y1 - 1999/7/5. N2 - Recently we demonstrated that recombinant Cry1Ac protoxin from Bacillus thuringiensis is a potent systemic and mucosal immunogen. In this study we compared the adjuvant effects of Cry1Ac and cholera toxin (CT) for the hepatitis B surface antigen (HBsAg) and bovine serum albumin (BSA). The antibody responses of intestinal secretions and serum were determined by ELISA in Balb/c mice immunized through the intragastric (IG) or intraperitoneal (IP) routes. When HBsAg was administered via IG, the anti- HBsAg intestinal response was not enhanced by either Cry1Ac or CT, whereas via IP Cry1Ac increased the anti-HBsAg intestinal immunoglobulin (Ig)G response and CT increased the intestinal IgA and IgM responses. Serum anti- BSA antibodies ...
The bio-insecticide Bacillus thuringiensis israelensis (Bti) has worldwide become the most commonly used agentin mosquito control programs that pursue two main objectives: the control of vector-borne diseases and the reduction of nuisance, mainly coming frommosquitoes that emerge in large quantities from seasonal wetlands. The Upper Rhine Valley, a biodiversity hotspot in Germany, has been treated withBti for decades to reduce mosquito-borne nuisance and increase human well-being.Although Btiis presumed to be an environmentally safe agent,adverse effects on wetland ecosystems are still a matter of debate especially when it comes to long-term and indirect effects on non-target organisms. In light of the above, this thesis aims at investigating direct and indirect effects of Bti-based mosquito control on non-target organisms within wetland food chains.Effects were examinedin studies with increasingeco(toxico)logical complexity, ranging from laboratory over mesocosm to field approaches with a focus on the
Institut Pertanian Bogor (IPB) (2001) Komposisi media dan teknologi sederhana produksi bioinsektisida dari bacillus thuringiensis subsp kurstaki. S00200100120. ...
The action of activated 27,000 Mr toxin from Bacillus thuringiensis var. israelensis (Bti toxin) on Malpighian tubules of Rhodnius prolixus has been investigated. Its binding to the tubules is slowed by low temperature but is not prevented even at 0 degree C. The binding is less effective at pH 10 than at pH7. Pretreatment of the tubules with 0.1 mmol l-1 ouabain or bumetanide or 1 mumol l-1 5-hydroxytryptamine did not affect the toxicity of the toxin. The toxin causes very large changes in the trans-epithelial potential difference; it changes from 40 mV, lumen negative, often to more than 100 mV, lumen positive. This reflects an initial collapse of the potential of the basal cell membrane, followed by a large positive-going potential change at the luminal cell membrane. Just prior to the effects of the toxin on rapid fluid secretion, the basal cell membrane becomes permeable to sucrose molecules. Raffinose at 170 mmol l-1 in the bathing solution does not protect the tubules from Bti toxin ...
Cry4Ba is a δ-endotoxin produced by Bacillus thuringiensis subsp. israelensis and Cyt2Aa2 is a cytolytic δ-endotoxin produced by B. thuringiensis subsp. darmstadiensis. Cry4Ba produced in Escherichia coli was toxic to Aedes aegypti larvae (LC50= 140 ng ml-1) but virtually inactive to Culex quinquefasciatus larvae. Cyt2Aa2 expressed in E. coli exhibited moderate activity against A. aegypti and C. quinquefasciatus larvae with LC50values of 350 and 250 ng ml-1, respectively. Co-expression of both toxins in E. coli dramatically increased toxicity to both A. aegypti andC. quinquefasciatus larvae (LC50= 7 and 20 ng ml-1, respectively). This is the first report to demonstrate that Cry4Ba and Cyt2Aa2 have high synergistic activity against C. quinquefasciatus larvae. © 2005 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved ...
Structural stability of Bacillus thuringiensis delta-endotoxin homolog-scanning mutants determined by susceptibility to proteases
TY - JOUR. T1 - ABCC2 is associated with Bacillus thuringiensis Cry1Ac toxin oligomerization and membrane insertion in diamondback moth. AU - Ocelotl,Josue. AU - Sánchez,Jorge. AU - Gómez,Isabel. AU - Tabashnik,Bruce E.. AU - Bravo,Alejandra. AU - Soberón,Mario. PY - 2017/12/1. Y1 - 2017/12/1. N2 - Cry1A insecticidal toxins bind sequentially to different larval gut proteins facilitating oligomerization, membrane insertion and pore formation. Cry1Ac interaction with cadherin triggers oligomerization. However, a mutation in an ABC transporter gene (ABCC2) is linked to Cry1Ac resistance in Plutella xylostella. Cry1AcMod, engineered to lack helix α-1, was able to form oligomers without cadherinbinding and effectively countered Cry1Ac resistance linked to ABCC2. Here we analyzed Cry1Ac and Cry1AcMod binding and oligomerization by western blots using brush border membrane vesicles (BBMV) from a strain of P. xylostella susceptible to Cry1Ac (Geneva 88) and a strain with resistance to Cry1Ac ...
Bacillus thuringiensis (Bt) is a Gram-positive, aerobic bacterium, producing parasporal crystals containing d-endotoxins responsible for its sele...
Bacillus thuringiensis ATCC ® 35646D-5™ Designation: Genomic DNA from Bacillus thuringiensis Strain USDA H522 TypeStrain=False Application:
TY - JOUR. T1 - Evolutionary trade-offs of insect resistance to Bacillus thuringiensis crops. T2 - Fitness cost affecting paternity. AU - Higginson, Dawn M.. AU - Morin, Shai. AU - Nyboer, Megan E.. AU - Biggs, Robert W.. AU - Tabashnik, Bruce E.. AU - Carrière, Yves. PY - 2005/4. Y1 - 2005/4. N2 - Evolution of resistance to insecticides provides a useful model for examining fitness trade-offs associated with adaptation to stress. Here, we examined male reproductive costs in pink bollworm (Pectinophora gossypiella) resistant to an insecticidal protein of Bacillus thuringiensis (Bt) produced by transgenic cotton, using contrasts between two pairs of related susceptible and resistant strains. Without competition for access to females, no costs affecting reproductive success of resistant males were observed. Resistant and susceptible males had similar mating frequency and fertility. Additionally, fecundity of females mated to resistant and susceptible males was comparable. In competition for ...
In Sub Saharan Africa malaria remains one of the major health problems and its control represents an important public health measure. Integrated malaria control comprises the use of impregnated mosquito nets and indoor residual spraying. The use of drugs to treat patients can create additional pressure on the equation of malaria transmission. Vector control may target the adult mosquitoes or their aquatic larval stages. Biological larvicides such as Bacillus thuringiensis israelensis (Bti) represent a promising approach to support malaria control programs by creating additional pressure on the equation of malaria transmission. In this study we examined the efficacy of a water-dispersible granule formulation (WDG) of the biological larvicide Bti (VectoBac®) against wild Anopheles spp. larvae. Different concentrations of the larvicide were tested in standardized plastic tubs in the field against untreated controls. In weekly intervals tubs were treated with fixed concentrations of larvicide and the
Comparative susceptibility and binding of Cry1 Bacillus thuringiensis toxins to the Asian (Ostrinia furnacalis Guenée) and European (Ostrinia nubilalis Hübner) corn borers (Lepidoptera: Crambidae ...
ENDOTOXINE (TOXIKOLOGIE); BACILLUS THURINGIENSIS (MIKROBIOLOGIE); IN-VITRO UNTERSUCHUNGEN (TOXIKOLOGIE); ENDOTOXINS (TOXICOLOGY); BACILLUS THURINGIENSIS (MICROBIOLOGY); IN VITRO STUDIES (TOXICOLOGY ...
... , or Bt, is a widely-used microbial biological insect control. Bt is a bacterium that produces crystal proteins that poison, paralyze, and kill targeted pests after ingestion. Bt is found in soil all over the world in almost all types of terrain from desert to tundra. It was first discovered in 1901 by the Japanese biologist Shigetane Ishiwatari as he was investigating the death of large populations of silkworms. He named it Bacillus sotto although it was changed to Bacillus thuringiensis by Ernst Berliner in 1911, a German scientist who re-isolated it as the cause of death of the Mediterranean flour moth larvae. Farmers started using it in 1920 and there are currently more than 35 varieties of this naturally occurring, soil-borne bacterium ...
First Announcement THE PACIFIC RIM CONFERENCE ON BIOTECHNOLOGY OF BACILLUS THURINGIENSIS AND ITS IMPACT TO THE ENVIRONMENT October 17 - 21, 1994 In order to promote the use of BACILLUS THURINGIENSIS (B.t.)-based insecticides in the Pacific rim region, the conference is being organized by a group of scientists from the universities, government institutions, and B.t. industries from Taiwan, Japan, and the U.S.A. The conference will be held in the Academic Activity Center, Academia Sinica, Taipei, Taiwan, which can accommodate around 200 participants. In addition to the speakers from the U.S.A. and Canada, the conference organizers plan to invite as many speakers as possible from the Asia- Pacific area. The goals of the conference are: * To promote the biotechnolgy of B.t. for the agricultural industry; to exchange the latest information on strain isolation and identification; to review the current topics on the molecular biology of the insecticidal proteins, transgenic plants, resistance ...
Bacillus thuringiensis: A Cornerstone of Modern Agriculture explores the impact that one of the most prominent biologically based pesticides has had on pest control technology and the issues that surround its use. The book examines the development, use, and management of technologies derived from Bacillus thuringiensis (Bt), addressing the health, economic, environmental, and social concerns generated by the deployment of genetically engineered crops. Authors representing a diverse cross section of the international scientific community contribute review articles and research findings that address the use of Bt in microbial formulations and transgenic crops, technological advances in the genetic engineering of plants, advances in methodologies, and improved agricultural practices and productivity through the use of Bt cotton ...
Data on 6,500 pesticides, insecticides and herbicides including toxicity, water pollution, ecological toxicity, uses and regulatory status.
Bacillus Thuringiensis Bt Definition - Bacillus thuringiensis (Bt) is a type of spore-forming bacterium. Bt occurs naturally in the soil of all types of...
O B. thuringiensis descubriuno en 1901 o biólogo xaponés Ishiwata Shigetane.[3] En 1911, foi redescuberto en Alemaña por Ernst Berliner, que o illou como causante dunha enfermidade nas eirugas das avelaíñas da fariña. En 1976, Robert A. Zakharyan informou da presenza dun plásmido nunha cepa de B. thuringiensis e suxeriu que o plásmido estaba implicado na formación de endósporas e cristais.[4][5] B. thuringiensis está moi relacionado coa bacteria do solo B.cereus e con B.anthracis: os tres organismos difiren principalmente nos plásmidos que posúen.[6] páx. 34-35 Igual que outros membros do xénero Bacillus, estas tres especies son aerobias e poden formar endósporas.[1] Cando esporula, B. thuringiensis forma cristais de δ-endotoxinas proteináceas insecticidas (chamadas proteínas cristalinas ou Cry, do inglés crystal), que están codificadas por xenes cry.[7] Na maioría das cepas de B. thuringiensis, os xenes cry están localizados nun plásmido, polo que non é un xene ...
Bacillus thuringiensis serotype kurstaki (Btk) is a group of bacteria used as biological control agents against lepidopterans. Btk, along with other B. thuringiensis products, is one of the most widely used biological pesticides due to its high specificity; it is effective against lepidopterans, and it has little to no effect on nontarget species. During sporulation, Btk produces a crystal protein that is lethal to lepidopteran larvae. Once ingested by the insect, the dissolution of the crystal allows the protoxin to be released. The toxin is then activated by the insect gut juice, and it begins to break down the gut. Btk is available commercially and is commonly known as "Garden Dust" or "Caterpillar Killer", both of which are produced by Safer Brand. Other Btk-producing companies include Bonide and Monterey. Btk is generally regarded as environmentally safe, as its toxicity is essentially limited to its target pest; humans, wildlife, and beneficial insects are regarded as unaffected by the ...
Árvores de Grevillea robusta utilizadas em arborização em Viçosa (MG) são, todos os anos, desfolhadas por lagartas de Eustema serice (Lepidóptera; Notodontidae). Com o objetivo de promover o controle, sem contudo oferecer risco às pessoas, procurou-se testar, em laboratório, dosagens de Bacillus thuringiensis, para recomendação posterior em aplicação no campo. Foi utilizado o produto comercial dipel, em três dosagens: 200, 400 e 600 g pc/ha, colocando-se as folhas pulverizadas à disposição das lagartas pelo período de 24 horas e substituindo-as, posteriormente, por folhas não-tratadas. Obteve-se excelente mortalidade nos três tratamentos, com melhor performance para a dosagem de 400 g pc/ha, já no sexto dia da aplicação do dipel. Recomenda-se, para controle em condições de campo, testar dosagens menores que 200 g pc/ha, pois se o produto ficar à disposição das lagartas, por período superior ao do ensaio, a eficiência poderá ser aumentada ...
Zhang, B., Bai, Z., Hoefel, D., Tang, L., Yang, Z., Zhuang, G., Yang, J. and Zhang, H. (2008), Assessing the impact of the biological control agent Bacillus thuringiensis on the indigenous microbial community within the pepper plant phyllosphere. FEMS Microbiology Letters, 284: 102-108. doi: 10.1111/j.1574-6968.2008.01178.x ...
On the market since 1996, genetically modified plants expressing an insecticidal toxin (Cry toxin stemmed from Bacillus thuringiensis) target several lepidopteran and coleopteran pests. In this study, we assessed the impact of two varieties of Bt maize producing different toxins (Cry1Ab or Cry1Fa, respectively) on the biology of a storage pest: Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae). The Indianmeal moths were susceptible to both toxins but showed an escape behavior only from Cry1Fa. The weight of females issued from larvae reared on Cry1Ab increased with increasing toxin concentration, but adults of both sexes reared on Cry1Fa had decreased weight. Both toxins increased development time from egg to adult regardless of sex and had no impact on the male adult lifespan. Finally, we recorded a time lag between metamorphosis from the non-Bt and the Bt diets, which increased proportionally to Cry concentration in the Bt diet.
For a surrogate bacterium to be used in outdoor studies, it is important to consider environmental and human safety and ease of detection. Recently, Bacillus thuringiensis, a popular bioinsecticide bacterium, has been gaining attention as a surrogate bacterium for use in biodefense. In this study, we constructed simulant strains of B. thuringiensis with enhanced characteristics for environmental studies. Through transposon mutagenesis, pigment genes were inserted into the chromosome, producing yellow-colored colonies for easy detection. To prevent persistence of spores in the environment, a genetic circuit was designed to produce a spore without sporulation capability. Two loxP sites were inserted, one on each side of the spo0A gene, which encodes a sporulation master regulator, and a sporulation-dependent Cre expression cassette was inserted into the chromosome. This genetic circuit successfully deleted spo0A during sporulation, producing spores that lacked the spo0A gene. In addition, two ...
The Vip3 proteins produced during vegetative growth by strains of the bacterium Bacillus thuringiensis show insecticidal activity against lepidopteran insects with a mechanism of action that may involve pore formation and apoptosis. These proteins are promising supplements to our arsenal of insecticidal proteins, but the molecular details of their activity are not understood. As a first step in the structural characterisation of these proteins, we have analysed their secondary structure and resolved the surface topology of a tetrameric complex of the Vip3Ag4 protein by transmission electron microscopy. Sites sensitive to proteolysis by trypsin are identified and the trypsin-cleaved protein appears to retain a similar structure as an octomeric complex comprising four copies each of the ~65 kDa and ~21 kDa products of proteolysis. This processed form of the toxin may represent the active toxin. The quality and monodispersity of the protein produced in this study make Vip3Ag4 a candidate for more detailed
The Vip3 proteins produced during vegetative growth by strains of the bacterium Bacillus thuringiensis show insecticidal activity against lepidopteran insects with a mechanism of action that may involve pore formation and apoptosis. These proteins are promising supplements to our arsenal of insecticidal proteins, but the molecular details of their activity are not understood. As a first step in the structural characterisation of these proteins, we have analysed their secondary structure and resolved the surface topology of a tetrameric complex of the Vip3Ag4 protein by transmission electron microscopy. Sites sensitive to proteolysis by trypsin are identified and the trypsin-cleaved protein appears to retain a similar structure as an octomeric complex comprising four copies each of the ~65 kDa and ~21 kDa products of proteolysis. This processed form of the toxin may represent the active toxin. The quality and monodispersity of the protein produced in this study make Vip3Ag4 a candidate for more ...
Evolution of resistance by insect pests threatens the continued effectiveness of Bacillus thuringiensis (Bt) toxins in sprays and transgenic crops. Fitness costs of Bt resistance occur when, in the absence of Bt toxins, fitness is lower for resistant insects than for susceptible insects. Modeling results show that fitness costs can delay resistance by selecting against Bt-resistant genotypes in refuges where insects are not exposed to Bt toxins. In 77 studies including 18 species, fitness costs were detected in 62% of experiments testing for declines in resistance and in 34% of fitness component comparisons. Mean fitness costs were 15.5% for survival, 7.4% for development time, and 2.5% for mass. Although most fitness costs were recessive, nonrecessive costs can select more strongly against resistance. Because fitness costs vary with ecological conditions, refuges designed to increase the dominance or magnitude of fitness costs could be especially useful for delaying pest resistance. ...
Bacillus thuringiensis (Bt) crops are plants genetically engineered (modified) to contain the endospore (or crystal) toxins of the bacterium, Bt to be resistant to certain insect pests. In 1995, the Environmental Protection Agency (EPA) in USA approved the commercial production and distribution of the Bt crops: corn, cotton, potato, and tobacco. Currently, the most common Bt crops are corn and cotton. The crystal, referred to as Cry toxins, is proteins formed during sporulation of some Bt strains and aggregate to form crystals. Such Cry toxins are toxic to specific species of insects belongs to orders: Lepidoptera, Coleoptera, Hymenoptera, Diptera, and Nematoda. In 2016, the total world area cultivated with genetically modified crops (GM crops) reached about 185 million ha. This review shows that there is a worldwide controversy about the safety of Bt crops to the environment and mammals. Some researchers support the cultivation of Bt crops depending upon the results of their laboratory and field
Bacillus thuringiensis (Bt) has been used as a biopesticide in agriculture, forestry and mosquito keep watch over due to its merits of particular toxicity opposed to aim bugs, loss of polluting residues and security to non-target organisms. The insecticidal homes of this bacterium are because of insecticidal proteins produced in the course of sporulation. regardless of those ecological merits, using Bt biopesticides has lagged in the back of the bogus chemical compounds. Genetic development of Bt traditional lines, particularly Bt recombination, bargains a promising technique of bettering efficacy and cost-effectiveness of Bt-based bioinsecticide items to improve new biotechnological functions. nevertheless, the several Bacillus species have vital biotechnological functions; certainly one of them is conducted by way of generating secondary metabolites, that are the examine item of usual product chemistry. the fantastic structural variability of those compounds has attracted the interest of ...
The sugarcane borer, Diatraea saccharalis, is a major target pest of transgenic corn expressing Bacillus thuringiensis (Bt) proteins in many areas of the U.S. mid-southern region. A Cry1Ab-resistant (Cry1Ab-RR) strain of D. saccharalis has been developed from a single two-parent family-line. To examine the molecular mechanisms of the Cry1Ab resistance in this insect strain, cDNAs of five types of potential candidate genes related to Bt resistance were sequenced using reverse transcriptase polymerase chain reaction (RT-PCR) and 5 rapid amplification of cDNA end (5 RACE). The Bt resistance candidate genes examined included three trypsins (DsTRYs), three chymotrypsins (DsCHYs), three aminopeptidases N (DsAPNs), one cadherin (DsCAD1), and three alkaline phosphatases (DsALPs). cDNA sequence of each gene and its expression levels were compared between a Cry1Ab-susceptible strain (Cry1Ab-SS) and the Cry1Ab-RR at different larval growth stages. The cDNA sequences of these genes were identical between Cry1Ab
Bacillus thuringiensis, which is a Gram-positive bacteria. It can produce insecticidal crystal proteins(ICP) which are proteolytically processed by gut proteases into the activated δ-endotoxins. The toxins activated by gut proteases bind to specific binding sites on the brush border membranes of insect midgut epithelial cells. The conformational change in the toxin molecules triggers the insertion of their pore-forming domain into the membrane. Finally, colloid-osmotic swelling and lysis of the cell result in the death of the larvae. Cry11Aa protein is one of the crystal protein coded in Bacillus thuringiensis subsp. Israelensis and it is highly toxic to certain dipteran larvae, such as Aedes, and Anopheles larvae. The length of Cry11Aa sequence is about 1.9Kb. In our project, the cry weapon system produce crystal protein, targetting the wrigglers, larvae of mosquitoes. It is controlled by the tetR-repressible promoter PtetR(BBa_R0040), which in turn is regulated by a temperature control ...
Bacillus thuringiensis, which is a Gram-positive bacteria. It can produce insecticidal crystal proteins(ICP) which are proteolytically processed by gut proteases into the activated δ-endotoxins. The toxins activated by gut proteases bind to specific binding sites on the brush border membranes of insect midgut epithelial cells. The conformational change in the toxin molecules triggers the insertion of their pore-forming domain into the membrane. Finally, colloid-osmotic swelling and lysis of the cell result in the death of the larvae. Cry11Aa protein is one of the crystal protein coded in Bacillus thuringiensis subsp. Israelensis and it is highly toxic to certain dipteran larvae, such as Aedes, and Anopheles larvae. The length of Cry11Aa sequence is about 1.9Kb. In our project, the cry weapon system produce crystal protein, targetting the wrigglers, larvae of mosquitoes. It is controlled by the tetR-repressible promoter PtetR(BBa_R0040), which in turn is regulated by a temperature control ...
During the past decade, growing public awareness of the impact of pesticides on food and enviromental safety has significantly affected the pest control industry. Several organizations (scientific, consumer, enviromental and governmental) have called for more severe restrictions on the use of toxic chemicals and increased funding for the development of alternative pest control methods (Gelernter, 1990). This has been a major stimulus for renewed interest in the use of microbial control agents, which have an excellent safety record and maybe produced using renewable raw-materials. Many of these agents can be integrated with chemical and other pest management techniques. Among the microbial agents that offer great potential in this respect is Bacillus thuringiensis (B.t.) (Davidson and Sweeney, 1983). B.t. based products account for 90-95% of the total bio-pesticide markeb_(Feitelson et al., 1992). Worldwide sales of B.t. products have. grown from $24 million in 1980 to $107 million -in 1989. ...
IBARGUCHI MENDIA, María de los Ángeles (2008) Toxinas cry de bacillus thuringiensis (berliver) para el control de las plagas de algón. Earias insulana (beisduval) yhelicorecpa armígera (hubner). PhD thesis, UPNA.. Texto completo no está disponible desde este repositorio ...
Novel transformation vectors containing novel chimeric genes allow the introduction of exogenous DNA fragments coding for polypeptide toxins produced by Bacillus thuringiensis or having substantial sequence homology to a gene coding for a polypeptide toxin as described herein and expression of the chimeric gene in plant cells and their progeny after integration into the plant cell genome. Transformed plant cells and their progeny exhibit stably inherited polypeptide toxin expression useful for protecting said plant cells and their progeny against certain insect pests and in controlling said insect pests.
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Efimtsev E.I.; Burov G.P.; Solomin A.A., 1990: Quantitative determination of beta exotoxin of bacillus thuringiensis in insecticide biopreparations
Bacillus thuringiensis (Bt) eggplant or bt talong in Philippine dialect was genetically redesigned to be resistant to the fruit and shoot borer larva that affects crop yielding from 50-70 percent.. Read moreScientist Warns About Risk Of Bt Eggplant. ...
Domain combinations containing the PKD domain superfamily in Bacillus thuringiensis str. Al Hakam. Domain architectures illustrate each occurrence of the PKD domain superfamily.
Negative staining image of Bacillus thuringiensis, which produces spores and crystals in times of stress. The image was taken using transmission elec...
Negative staining image of Bacillus thuringiensis, which produces spores and crystals in times of stress. The image was taken using transmission elec...
Purchase Recombinant Bacillus thuringiensis Dihydroorotate dehydrogenase B (NAD(+)), catalytic subunit. It is produced in Yeast. High purity. Good price.
Cry6Aa is a toxic crystal protein generated by the bacterial family Bacillus thuringiensis during sporulation. This protein is a member of the alpha pore forming toxins family, which gives it insecticidal qualities advantageous in agricultural pest control. Each Cry protein has some level of target specificity; Cry6Aa has specific toxic action against coleopteran insects and nematodes. The corresponding B. thuringiensis gene, cry6aa, is located on bacterial plasmids. Along with several other Cry protein genes, cry6aa can be genetically recombined in Bt corn and Bt cotton so the plants produce specific toxins. Insects are developing resistance to the most commonly inserted proteins like Cry1Ac. Since Cry6Aa proteins function differently than other Cry proteins, they are combined with other proteins to decrease the development of pest resistance. Recent studies suggest this protein functions better in combination with other virulence factors such as other Cry proteins and metalloproteinases. ...