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Sample records for bacillus thuringiensis bioinsecticides

  1. Bacillus thuringiensis: A story of a successful bioinsecticide

    PubMed Central

    Bravo, Alejandra; Likitvivatanavong, Supaporn; Gill, Sarjeet S.; Soberón, Mario

    2013-01-01

    Bacillus thuringiensis (Bt) bacteria are insect pathogens that rely on insecticidal pore forming proteins known as Cry and Cyt toxins to kill their insect larval hosts. At least four different non-structurally related families of proteins form the Cry toxin group of toxins. The expression of certain Cry toxins in transgenic crops has contributed to an efficient control of insect pests resulting in a significant reduction in chemical insecticide use. The mode of action of the three domain Cry toxin family involves sequential interaction of these toxins with several insect midgut proteins facilitating the formation of a pre-pore oligomer structure and subsequent membrane insertion that leads to the killing of midgut insect cells by osmotic shock. In this manuscript we review recent progress in understanding the mode of action of this family of proteins in lepidopteran, dipteran and coleopteran insects. Interestingly, similar Cry-binding proteins have been identified in the three insect orders, as cadherin, aminopeptidase-N and alkaline phosphatase suggesting a conserved mode of action. Also, recent data on insect responses to Cry toxin attack is discussed. Finally, we review the different Bt based products, including transgenic crops, that are currently used in agriculture. PMID:21376122

  2. Overcome of Carbon Catabolite Repression of Bioinsecticides Production by Sporeless Bacillus thuringiensis through Adequate Fermentation Technology.

    PubMed

    Ben Khedher, Saoussen; Jaoua, Samir; Zouari, Nabil

    2014-01-01

    The overcoming of catabolite repression, in bioinsecticides production by sporeless Bacillus thuringiensis strain S22 was investigated into fully controlled 3 L fermenter, using glucose based medium. When applying adequate oxygen profile throughout the fermentation period (75% oxygen saturation), it was possible to partially overcome the catabolite repression, normally occurring at high initial glucose concentrations (30 and 40 g/L glucose). Moreover, toxin production yield by sporeless strain S22 was markedly improved by the adoption of the fed-batch intermittent cultures technology. With 22.5 g/L glucose used into culture medium, toxin production was improved by about 36% when applying fed-batch culture compared to one batch. Consequently, the proposed fed-batch strategy was efficient for the overcome of the carbon catabolite repression. So, it was possible to overproduce insecticidal crystal proteins into highly concentrated medium. PMID:25309756

  3. Application of statistical experimental design for optimisation of bioinsecticides production by sporeless Bacillus thuringiensis strain on cheap medium

    PubMed Central

    Ben Khedher, Saoussen; Jaoua, Samir; Zouari, Nabil

    2013-01-01

    In order to overproduce bioinsecticides production by a sporeless Bacillus thuringiensis strain, an optimal composition of a cheap medium was defined using a response surface methodology. In a first step, a Plackett-Burman design used to evaluate the effects of eight medium components on delta-endotoxin production showed that starch, soya bean and sodium chloride exhibited significant effects on bioinsecticides production. In a second step, these parameters were selected for further optimisation by central composite design. The obtained results revealed that the optimum culture medium for delta-endotoxin production consists of 30 g L−1 starch, 30 g L−1 soya bean and 9 g L−1 sodium chloride. When compared to the basal production medium, an improvement in delta-endotoxin production up to 50% was noted. Moreover, relative toxin yield of sporeless Bacillus thuringiensis S22 was improved markedly by using optimised cheap medium (148.5 mg delta-endotoxins per g starch) when compared to the yield obtained in the basal medium (94.46 mg delta-endotoxins per g starch). Therefore, the use of optimised culture cheap medium appeared to be a good alternative for a low cost production of sporeless Bacillus thuringiensis bioinsecticides at industrial scale which is of great importance in practical point of view. PMID:24516462

  4. Bio-insecticide Bacillus thuringiensis spores encapsulated with amaranth derivatized starches: studies on the propagation "in vitro".

    PubMed

    Rodríguez, Ana Priscila García; Martínez, Marcela Gaytán; Barrera-Cortés, Josefina; Ibarra, Jorge E; Bustos, Fernando Martínez

    2015-02-01

    Bacillus thuringiensis (Bt) is one of the bioinsecticides used worldwide due to its specific toxicity against target pests in their larval stage. Despite this advantage, its use is limited because of their short persistence in field when exposed to ultra violet light and changing environmental conditions. In this work, microencapsulation has been evaluated as a promising method to improve Bt activity. The objective of this study was to develop and characterize native and modified amaranth starch granules and evaluate their potential application as wall materials in the microcapsulation of B thuringiensis serovar kurstaki HD-1 (Bt- HD1), produced by spray drying. Native amaranth starch granules were treated by hydrolyzation, high energy milling (HEM) and were chemically modified by phosphorylation and succinylation. The size of the Bt microcapsules varied from 12.99 to 17.14 μm adequate to protect the spores of Bt from ultraviolet radiation. The aw coefficient of the microcapsules produced by the modified starches after drying was low (0.14-1.88), which prevent microbial growth. Microcapsules prepared with phosphorylated amaranth starch presented the highest bacterial count and active material yield. Different concentrations of the encapsulated Bt formulation in phosphorylated amaranth starch showed a high level of insecticidal activity when tested on M. sexta larvae and has great potential to be developed as a bioinsecticide formulation, also, the level of toxicity is much higher than that found in some of the products commercially available. PMID:25168123

  5. Bioprocess design and economic analysis for the commercial production of environmentally friendly bioinsecticides from Bacillus thuringiensis HD-1 kurstaki.

    PubMed

    Rowe, Gerald E; Margaritis, Argyrios

    2004-05-20

    A production process for B. thuringiensis (Bt) bioinsecticides was designed in detail, including alternative batch, low-density fed-batch (LDFB), and high-density fed-batch (HDFB) fermentation configurations. Capital and operating costs, as well as profitability based on simple rate of return, were performed using a purpose-written FORTRAN program, explicitly analyzing production of a water-based flowable product used in forestry applications. The total capital cost was 18 million dollars (Canadian dollars) for a stand-alone plant with base-scale capacity of 3 x 10(7) billion international units (BIU)/year. Raw material costs amounted to 1.5 million dollars yearly, of which approximately half was for formulation ingredients. Per-unit production cost rose sharply for scales of less than 1 x 10(7) BIU/year, but was little affected by scale above 3 x 10(7) BIU/year. Product cost was much lower at all scales for a LDFB as opposed to batch fermentation process, but HDFB gave relatively little additional cost benefit. Profitability analysis performed by co-varying scale and selling price showed that break-even occurred at a price of 0.45 dollars/BIU for a batch process at base scale, while with LDFB fermentation the same production volume sold at 0.35 dollars/BIU gave a 12% rate of return. Since the assumed base scale would represent 8-15% of current world Bt bioinsecticide production, based on value or volume, it was concluded that profitability would require some or all of the following elements: targeting higher-value markets such as disease vector control, in addition to forestry; a potentially lower plant capacity (although at least 1 x 10(7) BIU/year;) and coproduction of other large-volume microbial products to absorb capacity and match bioinsecticide output to market demand. PMID:15112290

  6. Resistance to the Bacillus thuringiensis bioinsecticide in a field population of Plutella xylostella is due to a change in a midgut membrane receptor.

    PubMed

    Ferré, J; Real, M D; Van Rie, J; Jansens, S; Peferoen, M

    1991-06-15

    The biochemical mechanism for resistance to Bacillus thuringiensis crystal proteins was studied in a field population of diamondback moths (Plutella xylostella) with a reduced susceptibility to the bioinsecticidal spray. The toxicity and binding characteristics of three crystal proteins [CryIA(b), CryIB, and CryIC] were compared between the field population and a laboratory strain. The field population proved resistant (greater than 200-fold compared with the laboratory strain) to CryIA(b), one of the crystal proteins in the insecticidal formulation. Binding studies showed that the two strains differ in a membrane receptor that recognizes CryIA(b). This crystal protein did not bind to the brush-border membrane of the midgut epithelial cells of the field population, either because of strongly reduced binding affinity or because of the complete absence of the receptor molecule. Both strains proved fully susceptible to the CryIB and CryIC crystal proteins, which were not present in the B. thuringiensis formulation used in the field. Characteristics of CryIB and CryIC binding to brush-border membranes of midgut epithelial cells were virtually identical in the laboratory and the field population. PMID:2052591

  7. Bacillus thuringiensis

    PubMed Central

    Ibrahim, Mohamed A; Griko, Natalya; Junker, Matthew

    2010-01-01

    Bacillus thuringiensis (Bt) is a unique bacterium in that it shares a common place with a number of chemical compounds which are used commercially to control insects important to agriculture and public health. Although other bacteria, including B. popilliae and B. sphaericus, are used as microbial insecticides, their spectrum of insecticidal activity is quite limited compared to Bt. Importantly, Bt is safe for humans and is the most widely used environmentally compatible biopesticide worldwide. Furthermore, insecticidal Bt genes have been incorporated into several major crops, rendering them insect resistant, and thus providing a model for genetic engineering in agriculture. This review highlights what the authors consider the most relevant issues and topics pertaining to the genomics and proteomics of Bt. At least one of the authors (L.A.B.) has spent most of his professional life studying different aspects of this bacterium with the goal in mind of determining the mechanism(s) by which it kills insects. The other authors have a much shorter experience with Bt but their intellect and personal insight have greatly enriched our understanding of what makes Bt distinctive in the microbial world. Obviously, there is personal interest and bias reflected in this article notwithstanding oversight of a number of published studies. This review contains some material not published elsewhere although several ideas and concepts were developed from a broad base of scientific literature up to 2010. PMID:21327125

  8. Evaluation of different culture media for improvement in bioinsecticides production by indigenous Bacillus thuringiensis and their application against larvae of Aedes aegypti.

    PubMed

    Devidas, Patil Chandrashekhar; Pandit, Borase Hemant; Vitthalrao, Patil Satish

    2014-01-01

    Production of indigenous isolate Bacillus thuringiensis sv2 (Bt sv2) was checked on conventional and nonconventional carbon and nitrogen sources in shake flasks. The effects on the production of biomass, toxin production, and spore formation capability of mosquito toxic strain were determined. Toxicity differs within the same strain depending on the growth medium. Bt sv2 produced with pigeon pea and soya bean flour were found highly effective with LC50 < 4 ppm against larvae of Aedes aegypti. These results were comparable with bacteria produced from Luria broth as a reference medium. Cost-effective analyses have revealed that production of biopesticide from test media is highly economical. The cost of production of Bt sv2 with soya bean flour was significantly reduced by 23-fold. The use of nonconventional sources has yielded a new knowledge in this area as the process development aspects of biomass production have been neglected as an area of research. These studies are very important from the point of media optimization for economic production of Bacillus thuringiensis based insecticides in mosquito control programmes. PMID:24592157

  9. Evaluation of Different Culture Media for Improvement in Bioinsecticides Production by Indigenous Bacillus thuringiensis and Their Application against Larvae of Aedes aegypti

    PubMed Central

    Devidas, Patil Chandrashekhar; Pandit, Borase Hemant; Vitthalrao, Patil Satish

    2014-01-01

    Production of indigenous isolate Bacillus thuringiensis sv2 (Bt sv2) was checked on conventional and nonconventional carbon and nitrogen sources in shake flasks. The effects on the production of biomass, toxin production, and spore formation capability of mosquito toxic strain were determined. Toxicity differs within the same strain depending on the growth medium. Bt sv2 produced with pigeon pea and soya bean flour were found highly effective with LC50 < 4 ppm against larvae of Aedes aegypti. These results were comparable with bacteria produced from Luria broth as a reference medium. Cost-effective analyses have revealed that production of biopesticide from test media is highly economical. The cost of production of Bt sv2 with soya bean flour was significantly reduced by 23-fold. The use of nonconventional sources has yielded a new knowledge in this area as the process development aspects of biomass production have been neglected as an area of research. These studies are very important from the point of media optimization for economic production of Bacillus thuringiensis based insecticides in mosquito control programmes. PMID:24592157

  10. Susceptibility, mechanisms of response and resistance to Bacillus thuringiensis toxins in Spodoptera spp.

    PubMed

    Herrero, Salvador; Bel, Yolanda; Hernández-Martínez, Patricia; Ferré, Juan

    2016-06-01

    Bioinsecticides based on Bacillus thuringiensis have long been used as an alternative to synthetic insecticides to control insect pests. In this review, we focus on insects of the genus Spodoptera, including relevant polyphagous species that are primary and secondary pests of many crops, and how B. thuringiensis toxins can be used for Spodoptera spp. pest management. We summarize the main findings related to susceptibility, midgut binding specificity, mechanisms of response and resistance of this insect genus to B. thuringiensis toxins. PMID:27436737

  11. Bacillus thuringiensis (Bt)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Bacillus thuringiensis (Bt), a natural bacteria found all over the Earth, has a fairly novel way of getting rid of unwanted insects. Bt forms a protein substance (shown on the right) that is not harmful to humans, birds, fish or other vertebrates. When eaten by insect larvae the protein causes a fatal loss of appetite. For over 25 years agricultural chemical companies have relied heavily upon safe Bt pesticides. New space based research promises to give the insecticide a new dimension in effectiveness and applicability. Researchers from the Consortium for Materials Development in Space along with industrial affiliates such as Abott Labs and Pern State University flew Bt on a Space Shuttle mission in the fall of 1996. Researchers expect that the Shuttle's microgravity environment will reveal new information about the protein that will make it more effective against a wider variety of pests.

  12. Control of pine processionary moth, Thaumetopoea pityocampa with Bacillus thuringiensis in Antalya, Turkey.

    PubMed

    Cebeci, H Huseyin; Oymen, R Tamer; Acer, Sabiha

    2010-05-01

    Taumetopoea pityocampa (Den. and Schiff) is one of the most common defoliator insects found in Turkey. Although several methods have been used in attempting to control this major forest pest up to now but the problem still remains largely unsolved in Turkey. There is an urgent need to control and minimize the damages caused by these defoliating caterpillars. Therefore, we planned and applied field treatments using by Foray 76B and VBC 60074 to put forward to the efficiency of these bioinsecticides against PPM. The bioinsecticides included in Bacillus thuringiensis subsp. kurstaki (Btk). The vulnerable performance of a single application has been observed in the field trial of these bioinsecticides with mortality rates ranging from 97 to 99% in Turkey's pine forests. PMID:21047011

  13. Bacillus thuringiensis and Bacillus sphaericus biopesticides production.

    PubMed

    el-Bendary, Magda A

    2006-01-01

    The long residual action and toxicity of the chemical insecticides have brought about serious environmental problems such as the emergence and spread of insecticide resistance in many species of vectors, mammalian toxicity, and accumulation of pesticide residues in the food chain. All these problems have highlighted the need for alternative biological control agents. Entomo-pathogenic Bacillus thuringiensis (Bt) and Bacillus sphaericus (Bs) are two safe biological control agents. They have attracted considerable interest as possible replacements for the chemical insecticides. Although microbial insecticides based on Bt and Bs are available for use, their high cost makes large-scale application impracticable in developing countries. This review focuses on the economic production of these two microorganisms by submerged fermentation and solid state fermentation using agro-industrial by-products and other wastes. PMID:16598830

  14. Bacillus thuringiensis subsp. israelensis and Its Dipteran-Specific Toxins

    PubMed Central

    Ben-Dov, Eitan

    2014-01-01

    Bacillus thuringiensis subsp. israelensis (Bti) is the first Bacillus thuringiensis to be found and used as an effective biological control agent against larvae of many mosquito and black fly species around the world. Its larvicidal activity resides in four major (of 134, 128, 72 and 27 kDa) and at least two minor (of 78 and 29 kDa) polypeptides encoded respectively by cry4Aa, cry4Ba, cry11Aa, cyt1Aa, cry10Aa and cyt2Ba, all mapped on the 128 kb plasmid known as pBtoxis. These six δ-endotoxins form a complex parasporal crystalline body with remarkably high, specific and different toxicities to Aedes, Culex and Anopheles larvae. Cry toxins are composed of three domains (perforating domain I and receptor binding II and III) and create cation-selective channels, whereas Cyts are composed of one domain that acts as well as a detergent-like membrane perforator. Despite the low toxicities of Cyt1Aa and Cyt2Ba alone against exposed larvae, they are highly synergistic with the Cry toxins and hence their combinations prevent emergence of resistance in the targets. The lack of significant levels of resistance in field mosquito populations treated for decades with Bti-bioinsecticide suggests that this bacterium will be an effective biocontrol agent for years to come. PMID:24686769

  15. BOOK REVIEW – BACILLUS THURINGIENSIS: A CORNERSTONE OF MODERN AGRICULTURE BACILLUS THURINGIENSIS

    EPA Science Inventory

    Are you interested in the technical issues surrounding the use of Bacillus thuringiensis pesticidal traits as sprays and as plant incorporated protectants (transgenic crops)? Should the dimensions of human health, ecology, entomology, risk assessment, resistance management, and d...

  16. [Bacillus thuringiensis: a biotechnology model].

    PubMed

    Sanchis, V; Lereclus, D

    1999-01-01

    This paper is on the different biotechnological approaches that have been used to improve Bacillus thuringiensis (Bt) for the control of agricultural insect pests and have contributed to the successful use of this biological control agent; it describes how a better knowledge of the high diversity of Bt strains and toxins genes together with the development of efficient host-vector systems has made it possible to overcome a number of the problems associated with Bt based insect control measures. First we present an overview of the biology of Bt and of the mode of action of its insecticidal toxins. We then describe some of the progress that has been made in furthering our knowledge of the genetics of Bt and of its insecticidal toxin genes and in the understanding of their regulation. The paper then deals with the use of recombinant DNA technology to develop new Bt strains for more effective pest control or to introduce the genes encoding partial-endotoxins directly into plants to produce insect-resistant trangenic plants. Several examples describing how biotechnology has been used to increase the production of insecticidal proteins in Bt or their persistence in the field by protecting them against UV degradation are presented and discussed. Finally, based on our knowledge of the mechanism of transposition of the Bt transposon Tn4430, we describe the construction of a new generation of recombinant strains of Bt, from which antibiotic resistance genes and other non-Bt DNA sequences were selectively eliminated, using a new generation of site-specific recombination vectors. In the future, continuing improvement of first generation products and research into new sources of resistance is essential to ensure the long-term control of insect pests. Chimeric toxins could also be produced so as to increase toxin activity or direct resistance towards a particular type of insect. The search for new insecticidal toxins, in Bt or other microorganisms, may also provide new weapons

  17. Narrow terahertz attenuation signatures in Bacillus thuringiensis.

    PubMed

    Zhang, Weidong; Brown, Elliott R; Viveros, Leamon; Burris, Kellie P; Stewart, C Neal

    2014-10-01

    Terahertz absorption signatures from culture-cultivated Bacillus thuringiensis were measured with a THz photomixing spectrometer operating from 400 to 1200 GHz. We observe two distinct signatures centered at ∼955 and 1015 GHz, and attribute them to the optically coupled particle vibrational resonance (surface phonon-polariton) of Bacillus spores. This demonstrates the potential of the THz attenuation signatures as "fingerprints" for label-free biomolecular detection. PMID:23821459

  18. Distribution of phenotypes among Bacillus thuringiensis strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An extensive collection of Bacillus thuringiensis isolates from around the world were phenotypically profiled using standard biochemical tests. Six phenotypic traits occurred in 20-86% of the isolates and were useful in distinguishing isolates: production of urease (U; 20.5% of isolates), hydrolysis...

  19. The Complete Genome Sequence of Bacillus thuringiensis AlHakam

    SciTech Connect

    Challacombe, Jean F.; Altherr, Michael R.; Xie, Gary; Bhotika,Smriti S.; Brown, Nancy; Bruce, David; Campbell, Connie S.; Campbell,Mary L.; Chen, Jin; Chertkov, Olga; Cleland, Cathy; Dimitrijevic, Mira; Doggett, Norman A.; Fawcett, John J.; Glavina, Tijana; Goodwin, Lynne A.; Green, Lance D.; Han, Cliff S.; Hill, Karen K.; Hitchcock, Penny; Jackson, Paul J.; Keim, Paul; Kewalramani, Avinash Ramesh; Longmire, Jon; Lucas, Susan; Malfatti, Stephanie; Martinez, Diego; McMurry, Kim; Meincke, Linda J.; Misra, Monica; Moseman, Bernice L.; Mundt, Mark; Munk,A. Christine; Okinaka, Richard T.; Parson-Quintana, B.; Reilly, LeePhilip; Richardson, Paul; Robinson, Donna L.; Rubin, Eddy; Saunders,Elizabeth; Tapia, Roxanne; Tesmer, Judith G.; Thayer, Nina; Thompson,Linda S.; Tice, Hope; Ticknor, Lawrence O.; Wills, Patti L.; Gilna, Paul; Brettin, Thomas S.

    2007-04-01

    Bacillus thuringiensis is an insect pathogen that is widelyused as a biopesticide (3). Here we report the finished, annotated genomesequence of B. thuringiensis Al Hakam, which was collected in Iraq by theUnited Nations Special Commission (2).

  20. A pangenomic study of Bacillus thuringiensis.

    PubMed

    Fang, Yongjun; Li, Zhaolong; Liu, Jiucheng; Shu, Changlong; Wang, Xumin; Zhang, Xiaowei; Yu, Xiaoguang; Zhao, Duojun; Liu, Guiming; Hu, Songnian; Zhang, Jie; Al-Mssallem, Ibrahim; Yu, Jun

    2011-12-20

    Bacillus thuringiensis (B. thuringiensis) is a soil-dwelling Gram-positive bacterium and its plasmid-encoded toxins (Cry) are commonly used as biological alternatives to pesticides. In a pangenomic study, we sequenced seven B. thuringiensis isolates in both high coverage and base-quality using the next-generation sequencing platform. The B. thuringiensis pangenome was extrapolated to have 4196 core genes and an asymptotic value of 558 unique genes when a new genome is added. Compared to the pangenomes of its closely related species of the same genus, B. thuringiensis pangenome shows an open characteristic, similar to B. cereus but not to B. anthracis; the latter has a closed pangenome. We also found extensive divergence among the seven B. thuringiensis genome assemblies, which harbor ample repeats and single nucleotide polymorphisms (SNPs). The identities among orthologous genes are greater than 84.5% and the hotspots for the genome variations were discovered in genomic regions of 2.3-2.8Mb and 5.0-5.6Mb. We concluded that high-coverage sequence assemblies from multiple strains, before all the gaps are closed, are very useful for pangenomic studies. PMID:22196399

  1. Bacillus thuringiensis Toxins: An Overview of Their Biocidal Activity

    PubMed Central

    Palma, Leopoldo; Muñoz, Delia; Berry, Colin; Murillo, Jesús; Caballero, Primitivo

    2014-01-01

    Bacillus thuringiensis (Bt) is a Gram positive, spore-forming bacterium that synthesizes parasporal crystalline inclusions containing Cry and Cyt proteins, some of which are toxic against a wide range of insect orders, nematodes and human-cancer cells. These toxins have been successfully used as bioinsecticides against caterpillars, beetles, and flies, including mosquitoes and blackflies. Bt also synthesizes insecticidal proteins during the vegetative growth phase, which are subsequently secreted into the growth medium. These proteins are commonly known as vegetative insecticidal proteins (Vips) and hold insecticidal activity against lepidopteran, coleopteran and some homopteran pests. A less well characterized secretory protein with no amino acid similarity to Vip proteins has shown insecticidal activity against coleopteran pests and is termed Sip (secreted insecticidal protein). Bin-like and ETX_MTX2-family proteins (Pfam PF03318), which share amino acid similarities with mosquitocidal binary (Bin) and Mtx2 toxins, respectively, from Lysinibacillus sphaericus, are also produced by some Bt strains. In addition, vast numbers of Bt isolates naturally present in the soil and the phylloplane also synthesize crystal proteins whose biological activity is still unknown. In this review, we provide an updated overview of the known active Bt toxins to date and discuss their activities. PMID:25514092

  2. [Effect of pesticides on Bacillus thuringiensis strains under controlled conditions].

    PubMed

    Salerno, C; Dias, S; Sagardoy, M

    1999-01-01

    Little is known about native populations of Bacillus thuringiensis (Bt) isolated from soils of Argentina. We undertook this study to determine the resistance to different pesticides of two commercial and fourteen native strains of Bt under in vitro conditions. An agar plate bioassay test conducted with ten pesticides and sixteen strains of Bt showed that Basagran, Scepter, Fungoxan and Decis were not toxic for the bioinsecticide bacteria at recommended application rates (RAR). In contrast, low concentrations (3.2% RAR) of Agil, Select and Isomero showed a deleterious effect on the bacteria investigated. Simultaneously, four of the pesticides were able to produce phenotypical changes on the Bt colonies grown on nutrient agar. Moreover, in a greenhouse experiment, seven pesticides applied at 1.6%, 12.5% and 100% RAR on soybean leaves were not as inhibitory as under in vitro conditions for two Bt strains (HD-1 and A61). However, survival of these strains in the phyllosphere of soybean differed significantly between untreated leaves and leaves treated with pesticides after 20 days of study (P < 0.05). Finally, and from an ecological point of view, these findings suggest that the addition of some pesticides to soybean leaves in lower concentrations than those recommended could be favourable for the persistence of Bt in this environment. PMID:10425660

  3. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage BMBtp2.

    PubMed

    Dong, Zhaoxia; Peng, Donghai; Wang, Yueying; Zhu, Lei; Ruan, Lifang; Sun, Ming

    2013-01-01

    Bacillus thuringiensis is an insect pathogen which has been widely used for biocontrol. During B. thuringiensis fermentation, lysogenic bacteriophages cause severe losses of yield. Here, we announce the complete genome sequence of a bacteriophage, BMBtp2, which is induced from B. thuringiensis strain YBT-1765, which may be helpful to clarify the mechanism involved in bacteriophage contamination. PMID:23405296

  4. Efficiency of Intergeneric Recombinants Between Bacillus Thuringiensis and Bacillus Subtilis for Increasing Mortality Rate in Cotten Leaf Worm

    NASA Astrophysics Data System (ADS)

    AlOtaibi, Saad Aied

    2012-12-01

    In this study , two strains of Bacillus belonging to two serotypes and four of their transconjugants were screened with respect to their toxicity against lepidopterous cotton pest. . Bacterial transconjugants isolated from conjugation between both strains were evaluated for their transconjugant efficiency caused mortality in Spodoptera littoralis larvae . Two groups of bioinsecticides ; crystals , crystals and spores have been isolated from Bacillusstrains and their transconjugants . Insecticidal crystal protein ( ICP ) was specific for lepidopteran insects because of the toxin sufficient both for insect specificity and toxicity . The toxicities of these two groups against larvae of Spodoptera littoralis was expressed as transconjugant efficiency , which related to the mean number of larvae died expressed as mortality percentage . The results showed transconjugant efficiency in reducing the mean number of Spodoptera littoralis larvae feeding on leaves of Ricinus communis sprayed with bioinsecticides of Bt transconjugants. Most values of positive transconjugant efficiency related to increasing mortality percentage are due to toxicological effects appeared in response to the treatments with crystals + endospores than that of crystals alone .This indicated that crystals + endospores was more effective for increasing mortality percentage than that resulted by crystals . Higher positive transconjugant efficiency in relation to the mid parents and better parent was appeared at 168 h of treatment . The results indicated that recombinant Bacillus thuringiensis are important control agents for lepidopteran pests , as well as , susceptibility decreased with larval development . The results also suggested a potential for the deployment of these recominant entomopathogens in the management of Spodoptera. littoralis larvae .

  5. Bacillus thuringiensis and Its Pesticidal Crystal Proteins

    PubMed Central

    Schnepf, E.; Crickmore, N.; Van Rie, J.; Lereclus, D.; Baum, J.; Feitelson, J.; Zeigler, D. R.; Dean, D. H.

    1998-01-01

    During the past decade the pesticidal bacterium Bacillus thuringiensis has been the subject of intensive research. These efforts have yielded considerable data about the complex relationships between the structure, mechanism of action, and genetics of the organism’s pesticidal crystal proteins, and a coherent picture of these relationships is beginning to emerge. Other studies have focused on the ecological role of the B. thuringiensis crystal proteins, their performance in agricultural and other natural settings, and the evolution of resistance mechanisms in target pests. Armed with this knowledge base and with the tools of modern biotechnology, researchers are now reporting promising results in engineering more-useful toxins and formulations, in creating transgenic plants that express pesticidal activity, and in constructing integrated management strategies to insure that these products are utilized with maximum efficiency and benefit. PMID:9729609

  6. Resistance to bio-insecticides or how to enhance their sustainability: a review.

    PubMed

    Siegwart, Myriam; Graillot, Benoit; Blachere Lopez, Christine; Besse, Samantha; Bardin, Marc; Nicot, Philippe C; Lopez-Ferber, Miguel

    2015-01-01

    After more than 70 years of chemical pesticide use, modern agriculture is increasingly using biological control products. Resistances to conventional insecticides are wide spread, while those to bio-insecticides have raised less attention, and resistance management is frequently neglected. However, a good knowledge of the limitations of a new technique often provides greater sustainability. In this review, we compile cases of resistance to widely used bio-insecticides and describe the associated resistance mechanisms. This overview shows that all widely used bio-insecticides ultimately select resistant individuals. For example, at least 27 species of insects have been described as resistant to Bacillus thuringiensis toxins. The resistance mechanisms are at least as diverse as those that are involved in resistance to chemical insecticides, some of them being common to bio-insecticides and chemical insecticides. This analysis highlights the specific properties of bio-insecticides that the scientific community should use to provide a better sustainability of these products. PMID:26150820

  7. Resistance to bio-insecticides or how to enhance their sustainability: a review

    PubMed Central

    Siegwart, Myriam; Graillot, Benoit; Blachere Lopez, Christine; Besse, Samantha; Bardin, Marc; Nicot, Philippe C.; Lopez-Ferber, Miguel

    2015-01-01

    After more than 70 years of chemical pesticide use, modern agriculture is increasingly using biological control products. Resistances to conventional insecticides are wide spread, while those to bio-insecticides have raised less attention, and resistance management is frequently neglected. However, a good knowledge of the limitations of a new technique often provides greater sustainability. In this review, we compile cases of resistance to widely used bio-insecticides and describe the associated resistance mechanisms. This overview shows that all widely used bio-insecticides ultimately select resistant individuals. For example, at least 27 species of insects have been described as resistant to Bacillus thuringiensis toxins. The resistance mechanisms are at least as diverse as those that are involved in resistance to chemical insecticides, some of them being common to bio-insecticides and chemical insecticides. This analysis highlights the specific properties of bio-insecticides that the scientific community should use to provide a better sustainability of these products. PMID:26150820

  8. Fluorescent Amplified Fragment Length Polymorphism Analysis of Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis Isolates

    PubMed Central

    Hill, Karen K.; Ticknor, Lawrence O.; Okinaka, Richard T.; Asay, Michelle; Blair, Heather; Bliss, Katherine A.; Laker, Mariam; Pardington, Paige E.; Richardson, Amber P.; Tonks, Melinda; Beecher, Douglas J.; Kemp, John D.; Kolstø, Anne-Brit; Wong, Amy C. Lee; Keim, Paul; Jackson, Paul J.

    2004-01-01

    DNA from over 300 Bacillus thuringiensis, Bacillus cereus, and Bacillus anthracis isolates was analyzed by fluorescent amplified fragment length polymorphism (AFLP). B. thuringiensis and B. cereus isolates were from diverse sources and locations, including soil, clinical isolates and food products causing diarrheal and emetic outbreaks, and type strains from the American Type Culture Collection, and over 200 B. thuringiensis isolates representing 36 serovars or subspecies were from the U.S. Department of Agriculture collection. Twenty-four diverse B. anthracis isolates were also included. Phylogenetic analysis of AFLP data revealed extensive diversity within B. thuringiensis and B. cereus compared to the monomorphic nature of B. anthracis. All of the B. anthracis strains were more closely related to each other than to any other Bacillus isolate, while B. cereus and B. thuringiensis strains populated the entire tree. Ten distinct branches were defined, with many branches containing both B. cereus and B. thuringiensis isolates. A single branch contained all the B. anthracis isolates plus an unusual B. thuringiensis isolate that is pathogenic in mice. In contrast, B. thuringiensis subsp. kurstaki (ATCC 33679) and other isolates used to prepare insecticides mapped distal to the B. anthracis isolates. The interspersion of B. cereus and B. thuringiensis isolates within the phylogenetic tree suggests that phenotypic traits used to distinguish between these two species do not reflect the genomic content of the different isolates and that horizontal gene transfer plays an important role in establishing the phenotype of each of these microbes. B. thuringiensis isolates of a particular subspecies tended to cluster together. PMID:14766590

  9. BOOK REVIEW: BACILLUS THURINGIENSIS: A CORNERSTONE OF MODERN AGRICULTURE

    EPA Science Inventory

    Are you interested in the technical issues surrounding the use of Bacillus thuringiensis pesticidal traits as sprays and as plant incorporated protectants (transgenic crops)? Should the dimensions of human health, ecology, entomology, risk assessment, resistance management, and d...

  10. CHARACTERIZATION OF THE PARASPORAL INCLUSION OF BACILLUS THURINGIENSIS VAR. KYUSHUENSIS

    EPA Science Inventory

    Bacillus thuringiensis var. kyushuensis synthesizes an irregularly shaped parasporal inclusion during sporulation. lectron microscopy revealed that the inclusions are composed of a relatively homogeneous appearing center surrounded by a thick, electron dense coating. urified incl...

  11. Haematological, biochemical and histopathological alterations induced by abamectin and Bacillus thuringiensis in male albino rats.

    PubMed

    Eissa, F I; Zidan, N A

    2010-03-01

    The renal- and hepato-toxicity induced by abamectin pesticide (Vertimec) and a commercial form of a bio-insecticide Bacillus thuringiensis (Agerin) in male albino rats were evaluated. Blood picture and blood glucose level were investigated. Male albino rats were administered dietary doses each equivalent to 1/10 or 1/100 of the LD50 values of each toxicant for 30 consecutive days. Abamectin was found to pose risks of renal- and hepato-toxicity in rats, since the biochemical parameters of liver function (i.e. aspartate aminotransferase activity, alanine aminotransferase activity, acid phosphatase activity, albumin, and total protein levels) and kidney function (uric acid and creatinine concentration) were severely affected. These effects were verified by histopathological examination of liver and kidney tissues. Likewise, some haematological indices (i.e. erythrocyte count, leukocyte count and haemoglobin concentration) were also influenced; in addition abamectin might cause hypoglycaemia. On the other hand, the above-mentioned lesions were less pronounced in the case of Bacillus thuringiensis -treated rats. PMID:20194097

  12. Bacillus thuringiensis Conjugation in Simulated Microgravity

    NASA Astrophysics Data System (ADS)

    Beuls, Elise; van Houdt, Rob; Leys, Natalie; Dijkstra, Camelia; Larkin, Oliver; Mahillon, Jacques

    2009-10-01

    Spaceflight experiments have suggested a possible effect of microgravity on the plasmid transfer among strains of the Gram-positive Bacillus thuringiensis, as opposed to no effect recorded for Gram-negative conjugation. To investigate these potential effects in a more affordable experimental setup, three ground-based microgravity simulators were tested: the Rotating Wall Vessel (RWV), the Random Positioning Machine (RPM), and a superconducting magnet. The bacterial conjugative system consisted in biparental matings between two B. thuringiensis strains, where the transfer frequencies of the conjugative plasmid pAW63 and its ability to mobilize the nonconjugative plasmid pUB110 were assessed. Specifically, potential plasmid transfers in a 0-g position (simulated microgravity) were compared to those obtained under 1-g (normal gravity) condition in each device. Statistical analyses revealed no significant difference in the conjugative and mobilizable transfer frequencies between the three different simulated microgravitational conditions and our standard laboratory condition. These important ground-based observations emphasize the fact that, though no stimulation of plasmid transfer was observed, no inhibition was observed either. In the case of Gram-positive bacteria, this ability to exchange plasmids in weightlessness, as occurs under Earth's conditions, should be seen as particularly relevant in the scope of spread of antibiotic resistances and bacterial virulence.

  13. Sludge based Bacillus thuringiensis biopesticides: viscosity impacts.

    PubMed

    Brar, S K; Verma, M; Tyagi, R D; Valéro, J R; Surampalli, R Y

    2005-08-01

    Viscosity studies were performed on raw, pre-treated (sterilised and thermal alkaline hydrolysed or both types of treatment) and Bacillus thuringiensis (Bt) fermented sludges at different solids concentration (10-40 g/L) for production of biopesticides. Correlations were established among rheological parameter (viscosity), solids (total and dissolved) concentration and entomotoxicity (Tx) of Bt fermented sludges. Exponential and power laws were preferentially followed by hydrolysed fermented compared to raw fermented sludge. Soluble chemical oxygen demand variation corroborated with increase in dissolved solids concentration on pre-treatments, contributing to changes in viscosity. Moreover, Tx was higher for hydrolysed fermented sludge in comparison to raw fermented sludge owing to increased availability of nutrients and lower viscosity that improved oxygen transfer. The shake flask results were reproducible in fermenter. This study will have major impact on selecting fermentation, harvesting and formulation techniques of Bt fermented sludges for biopesticide production. PMID:15979118

  14. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage Smudge.

    PubMed

    Cornell, Jessica L; Breslin, Eileen; Schuhmacher, Zachary; Himelright, Madison; Berluti, Cassandra; Boyd, Charles; Carson, Rachel; Del Gallo, Elle; Giessler, Caris; Gilliam, Benjamin; Heatherly, Catherine; Nevin, Julius; Nguyen, Bryan; Nguyen, Justin; Parada, Jocelyn; Sutterfield, Blake; Tukruni, Muruj; Temple, Louise

    2016-01-01

    Smudge, a bacteriophage enriched from soil using Bacillus thuringiensis DSM-350 as the host, had its complete genome sequenced. Smudge is a myovirus with a genome consisting of 292 genes and was identified as belonging to the C1 cluster of Bacillus phages. PMID:27540049

  15. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage Smudge

    PubMed Central

    Cornell, Jessica L.; Breslin, Eileen; Schuhmacher, Zachary; Himelright, Madison; Berluti, Cassandra; Boyd, Charles; Carson, Rachel; Del Gallo, Elle; Giessler, Caris; Gilliam, Benjamin; Heatherly, Catherine; Nevin, Julius; Nguyen, Bryan; Nguyen, Justin; Parada, Jocelyn; Sutterfield, Blake; Tukruni, Muruj

    2016-01-01

    Smudge, a bacteriophage enriched from soil using Bacillus thuringiensis DSM-350 as the host, had its complete genome sequenced. Smudge is a myovirus with a genome consisting of 292 genes and was identified as belonging to the C1 cluster of Bacillus phages. PMID:27540049

  16. Pathogenomic Sequence Analysis of Bacillus cereus and Bacillus thuringiensis Isolates Closely Related to Bacillus anthracis†

    PubMed Central

    Han, Cliff S.; Xie, Gary; Challacombe, Jean F.; Altherr, Michael R.; Bhotika, Smriti S.; Bruce, David; Campbell, Connie S.; Campbell, Mary L.; Chen, Jin; Chertkov, Olga; Cleland, Cathy; Dimitrijevic, Mira; Doggett, Norman A.; Fawcett, John J.; Glavina, Tijana; Goodwin, Lynne A.; Hill, Karen K.; Hitchcock, Penny; Jackson, Paul J.; Keim, Paul; Kewalramani, Avinash Ramesh; Longmire, Jon; Lucas, Susan; Malfatti, Stephanie; McMurry, Kim; Meincke, Linda J.; Misra, Monica; Moseman, Bernice L.; Mundt, Mark; Munk, A. Christine; Okinaka, Richard T.; Parson-Quintana, B.; Reilly, Lee Philip; Richardson, Paul; Robinson, Donna L.; Rubin, Eddy; Saunders, Elizabeth; Tapia, Roxanne; Tesmer, Judith G.; Thayer, Nina; Thompson, Linda S.; Tice, Hope; Ticknor, Lawrence O.; Wills, Patti L.; Brettin, Thomas S.; Gilna, Paul

    2006-01-01

    Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis are closely related gram-positive, spore-forming bacteria of the B. cereus sensu lato group. While independently derived strains of B. anthracis reveal conspicuous sequence homogeneity, environmental isolates of B. cereus and B. thuringiensis exhibit extensive genetic diversity. Here we report the sequencing and comparative analysis of the genomes of two members of the B. cereus group, B. thuringiensis 97-27 subsp. konkukian serotype H34, isolated from a necrotic human wound, and B. cereus E33L, which was isolated from a swab of a zebra carcass in Namibia. These two strains, when analyzed by amplified fragment length polymorphism within a collection of over 300 of B. cereus, B. thuringiensis, and B. anthracis isolates, appear closely related to B. anthracis. The B. cereus E33L isolate appears to be the nearest relative to B. anthracis identified thus far. Whole-genome sequencing of B. thuringiensis 97-27and B. cereus E33L was undertaken to identify shared and unique genes among these isolates in comparison to the genomes of pathogenic strains B. anthracis Ames and B. cereus G9241 and nonpathogenic strains B. cereus ATCC 10987 and B. cereus ATCC 14579. Comparison of these genomes revealed differences in terms of virulence, metabolic competence, structural components, and regulatory mechanisms. PMID:16621833

  17. Complete genome sequence of Bacillus thuringiensis strain HD521.

    PubMed

    Li, Qiao; Xu, Li Z; Zou, Ting; Ai, Peng; Huang, Gang H; Li, Ping; Zheng, Ai P

    2015-01-01

    Bacillus thuringiensis is the most widely used biological pesticide in the world. It belongs to the Bacillus cereus sensu lato group, which contains six species. Among these six species, B. thuringiensis, B. anthracis, and B. cereus have a low genetic diversity. B. thuringiensis strain HD521 shows maroon colony which is different from most of the B. thuringiensis strains. Strain HD521 also displays an ability to inhibit plant sheath blight disease pathogen (Rhizoctonia solani AG1 IB) growth and can form bipyramidal parasporal crystals consisting of three cry7 genes. These crystals have an insecticidal activity against Henosepilachna vigintioctomaculata larva (Coleoptera). Here we report the complete genome sequence of strain HD521, which has one chromosome and six circular plasmids. PMID:26380647

  18. An overview of the safety and biological effects of Bacillus thuringiensis Cry toxins in mammals.

    PubMed

    Rubio-Infante, Néstor; Moreno-Fierros, Leticia

    2016-05-01

    Crystal proteins (Cry) produced during the growth and sporulation phases of Bacillus thuringiensis (Bt) bacterium are known as delta endotoxins. These toxins are being used worldwide as bioinsecticides to control pests in agriculture, and some Cry toxins are used against mosquitoes to control vector transmission. This review summarizes the relevant information currently available regarding the biosafety and biological effects that Bt and its insecticidal Cry proteins elicit in mammals. This work was performed because of concerns regarding the possible health impact of Cry toxins on vertebrates, particularly because Bt toxins might be associated with immune-activating or allergic responses. The controversial data published to date are discussed in this review considering earlier toxicological studies of B. thuringiensis, spores, toxins and Bt crops. We discussed the experimental studies performed in humans, mice, rats and sheep as well as in diverse mammalian cell lines. Although the term 'toxic' is not appropriate for defining the effects these toxins have on mammals, they cannot be considered innocuous, as they have some physiological effects that may become pathological; thus, trials that are more comprehensive are necessary to determine their effects on mammals because knowledge in this field remains limited. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26537666

  19. Mechanism of Insect Resistance to the Microbial Insecticide Bacillus thuringiensis

    NASA Astrophysics Data System (ADS)

    van Rie, J.; McGaughey, W. H.; Johnson, D. E.; Barnett, B. D.; van Mellaert, H.

    1990-01-01

    Receptor binding studies show that resistance of a laboratory-selected Plodia interpunctella strain to a Bacillus thuringiensis insecticidal crystal protein (ICP) is correlated with a 50-fold reduction in affinity of the membrane receptor for this protein. The strain is sensitive to a second type of ICP that apparently recognizes a different receptor. Understanding the mechanism of resistance will provide strategies to prevent or delay resistance and hence prolong the usefulness of B. thuringiensis ICPs as environmentally safe insecticides.

  20. Bacillus thuringiensis: a genomics and proteomics perspective.

    PubMed

    Ibrahim, Mohamed A; Griko, Natalya; Junker, Matthew; Bulla, Lee A

    2010-01-01

    Bacillus thuringiensis (Bt) is a unique bacterium in that it shares a common place with a number of chemical compounds which are used commercially to control insects important to agriculture and public health. Although other bacteria, including B. popilliae and B. sphaericus, are used as microbial insecticides, their spectrum of insecticidal activity is quite limited compared to Bt. Importantly, Bt is safe for humans and is the most widely used environmentally compatible biopesticide worldwide. Furthermore, insecticidal Bt genes have been incorporated into several major crops, rendering them insect resistant, and thus providing a model for genetic engineering in agriculture.This review highlights what the authors consider the most relevant issues and topics pertaining to the genomics and proteomics of Bt. At least one of the authors (L.A.B.) has spent most of his professional life studying different aspects of this bacterium with the goal in mind of determining the mechanism(s) by which it kills insects. The other authors have a much shorter experience with Bt but their intellect and personal insight have greatly enriched our understanding of what makes Bt distinctive in the microbial world. Obviously, there is personal interest and bias reflected in this article notwithstanding oversight of a number of published studies. This review contains some material not published elsewhere although several ideas and concepts were developed from a broad base of scientific literature up to 2010. PMID:21327125

  1. Bacteriocins synthesized by Bacillus thuringiensis: generalities and potential applications

    PubMed Central

    Salazar-Marroquín, Elma Laura; Galán-Wong, Luis J.; Moreno-Medina, Víctor Ricardo; Reyes-López, Miguel Ángel; Pereyra-Alférez, Benito

    2016-01-01

    The members of the Bacillus thuringiensis group, commonly known as Bt, produce a huge number of metabolites, which show biocidal and antagonistic activity. B. thuringiensis is widely known for synthesizing Cry, Vip and Cyt proteins, active against insects and other parasporins with biocidal activity against certain types of cancerous cells. Nevertheless, B. thuringiensis also synthesizes compounds with antimicrobial activity, especially bacteriocins. Some B. thuringiensis bacteriocins resemble lantibiotics and other small linear peptides (class IIa) from the lactic acid bacteria bacteriocins classification system. Although many bacteriocins produced by Bt have been reported, there is no proper classification for them. In this work, we have grouped these based on molecular weight and functionality. Bacteriocins are small peptides synthesized by bacteria, presenting inhibitory activity against Gram-positive and Gram-negative bacteria and to a lesser extent against fungi. These molecules represent a good study model in the search for microbial control alternatives. Lactic acid bacteria produces a huge number of these types of molecules with great potential. Nonetheless, members of the Bacillus, cereus group, especially B. thuringiensis, emerge as an attractive alternative for obtaining bacteriocins showing novel activities. This review describes the potential applications of B. thuringiensis bacteriocins in the control of foodborne pathogens, environment and medical area. PMID:27340340

  2. Regulation of cry gene expression in Bacillus thuringiensis.

    PubMed

    Deng, Chao; Peng, Qi; Song, Fuping; Lereclus, Didier

    2014-01-01

    Bacillus thuringiensis differs from the closely related Bacillus cereus group species by its ability to produce crystalline inclusions. The production of these crystals mainly results from the expression of the cry genes, from the stability of their transcripts and from the synthesis, accumulation and crystallization of large amounts of insecticidal Cry proteins. This process normally coincides with sporulation and is regulated by various factors operating at the transcriptional, post-transcriptional, metabolic and post-translational levels. PMID:25055802

  3. Occurrence and significance of Bacillus thuringiensis on wine grapes.

    PubMed

    Bae, Sungsook; Fleet, Graham H; Heard, Gillian M

    2004-08-01

    Wine grapes harvested at different stages during cultivation from several vineyards in New South Wales, Australia, harboured Bacillus thuringiensis at viable populations of 10(2)-10(6) cfu/g. Commercial preparations of B. thuringiensis had been sprayed onto the grapes as a biological insecticide. B. thuringiensis (10(1)-10(3) cfu/ml) was isolated from grape juice and fermenting grape juice in a commercial winery. Although B. thuringiensis remained viable when inoculated at 10(3)-10(4) cfu/ml into grape juice and wine (pH 3.0-6.0), it did not grow. Using in vitro agar culture assays, B. thuringiensis inhibited several grape-associated yeasts and bacteria as well as various species of fungi associated with grape spoilage and ochratoxin A production. B. thuringiensis did not inhibit Saccharomyces cerevisiae in agar culture or during alcoholic fermentation of grape juice. B. thuringiensis inhibited the malolactic bacterium, Oenococcus oeni, in agar culture but not during mixed cultures in a liquid medium. PMID:15246241

  4. Impact of Entomopathogens on Pest Resistance to Bacillus thuringiensis.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adaptation by pest insects to the bacterium Bacillus thuringiensis (Bt) can alter their susceptibility to other pathogens. As the number of acres planted in crops engineered to produce Bt toxin increases, many key agricultural pests undergo strong selection to evolve resistance to Bt. In conjuncti...

  5. Parallel Evolution of Bacillus thuringiensis Toxin Resistance in Lepidoptera

    PubMed Central

    Baxter, Simon W.; Badenes-Pérez, Francisco R.; Morrison, Anna; Vogel, Heiko; Crickmore, Neil; Kain, Wendy; Wang, Ping; Heckel, David G.; Jiggins, Chris D.

    2011-01-01

    Despite the prominent and worldwide use of Bacillus thuringiensis (Bt) insecticidal toxins in agriculture, knowledge of the mechanism by which they kill pests remains incomplete. Here we report genetic mapping of a membrane transporter (ABCC2) to a locus controlling Bt Cry1Ac toxin resistance in two lepidopterans, implying that this protein plays a critical role in Bt function. PMID:21840855

  6. Interactions of transgenic Bacillus thuringiensis insecticidal crops with spiders (Araneae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetically modified crops expressing insecticidal proteins from Bacillus thuringiensis (Bt) have dramatically increased in acreage since their introduction in the mid-1990’s. Although the insecticidal mechanisms of Bt target specific pests, concerns persist regarding direct and indirect effects on...

  7. TRANSGENIC PLANTS EXPRESSING BACILLUS THURINGIENSIS DELTA-ENDOTOXINS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercial varieties of transgenic Bacillus thuringiensis (Bt) plants have been developed in many countries to control target pests. Initially, the expression of native Bt genes in plants was low due to mRNA instability, improper splicing, and post-translation modifications. Subsequently, modificati...

  8. The Complete Genome Sequence of Bacillus thuringiensis Al Hakam▿

    PubMed Central

    Challacombe, Jean F.; Altherr, Michael R.; Xie, Gary; Bhotika, Smriti S.; Brown, Nancy; Bruce, David; Campbell, Connie S.; Campbell, Mary L.; Chen, Jin; Chertkov, Olga; Cleland, Cathy; Dimitrijevic, Mira; Doggett, Norman A.; Fawcett, John J.; Glavina, Tijana; Goodwin, Lynne A.; Green, Lance D.; Han, Cliff S.; Hill, Karen K.; Hitchcock, Penny; Jackson, Paul J.; Keim, Paul; Kewalramani, Avinash Ramesh; Longmire, Jon; Lucas, Susan; Malfatti, Stephanie; Martinez, Diego; McMurry, Kim; Meincke, Linda J.; Misra, Monica; Moseman, Bernice L.; Mundt, Mark; Munk, A. Christine; Okinaka, Richard T.; Parson-Quintana, B.; Reilly, Lee Philip; Richardson, Paul; Robinson, Donna L.; Saunders, Elizabeth; Tapia, Roxanne; Tesmer, Judith G.; Thayer, Nina; Thompson, Linda S.; Tice, Hope; Ticknor, Lawrence O.; Wills, Patti L.; Gilna, Paul; Brettin, Thomas S.

    2007-01-01

    Bacillus thuringiensis is an insect pathogen that is widely used as a biopesticide (E. Schnepf, N. Crickmore, J. Van Rie, D. Lereclus, J. Baum, J. Feitelson, D. R. Zeigler, and D. H. Dean, Microbiol. Mol. Biol. Rev. 62:775-806, 1998). Here we report the finished, annotated genome sequence of B. thuringiensis Al Hakam, which was collected in Iraq by the United Nations Special Commission (L. Radnedge, P. Agron, K. Hill, P. Jackson, L. Ticknor, P. Keim, and G. Andersen, Appl. Environ. Microbiol. 69:2755-2764, 2003). PMID:17337577

  9. Comparative evaluation of phenoloxidase activity in different larval stages of four lepidopteran pests after exposure to Bacillus thuringiensis.

    PubMed

    Valadez-Lira, J A; Alcocer-Gonzalez, J M; Damas, G; Nuñez-Mejía, G; Oppert, B; Rodriguez-Padilla, C; Tamez-Guerra, P

    2012-01-01

    Microbial entomopathogen-based bioinsecticides are recognized as alternatives to synthetic pesticides. Insects defend themselves against microbial pathogens by innate mechanisms, including increased phenoloxidase (PO) activity, but its relationship with microbial bioinsecticides efficacy is little known. This study evaluated the differences in PO activity at different developmental stages of the tobacco budworm Heliothis virescens Fabricius (Lepidoptera: Noctuidae), Indian meal moth Plodia interpunctella (Hübner) (Pyralidae), beet armyworm Spodoptera exigua (Hübner) (Noctuidae), and cabbage looper Trichoplusia ni (Hübner) (Noctuidae). Additionally, 2(nd)- and 4(th)-instars were exposed to the LC(50) value of the commercial Bacillus thuringiensis (Bt) spray, Biobit(®). The percentage of insecticidal activity (IA%) on 2(nd)-instar Biobit-exposed larvae was approximately the predicted 50 % mortality for all species except S. exigua. With all 4(th) instar Biobit-exposed larvae, mortality was not significantly different from that of unexposed larvae. Unexposed insects had a significantly higher PO activity in pre-pupae and pupae than early-instar larvae and adults, whereas PO activity was higher in adult females than in males. Correlation analysis between IA% and PO activity revealed significant r-values (p < 0.01) in 2(nd) instar H. virescens (r = 0.979) and P. interpunctella (r = 0.930). Second instar Biobit-exposed P. interpunctella had 10 times more PO activity than unexposed larvae. Similarly, the amount of total protein was lower in 4(th) instar Biobit-exposed H. virescens and higher in S. exigua. Therefore, the results indicated a relationship between Biobit susceptibility and PO activity in some cases. This information may be useful if the Biobit application period is timed for a developmental stage with low PO activity. However, more studies are needed to determine the correlation of each insect with a particular bioinsecticide. PMID:23414117

  10. Phages Preying on Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis: Past, Present and Future

    PubMed Central

    Gillis, Annika; Mahillon, Jacques

    2014-01-01

    Many bacteriophages (phages) have been widely studied due to their major role in virulence evolution of bacterial pathogens. However, less attention has been paid to phages preying on bacteria from the Bacillus cereus group and their contribution to the bacterial genetic pool has been disregarded. Therefore, this review brings together the main information for the B. cereus group phages, from their discovery to their modern biotechnological applications. A special focus is given to phages infecting Bacillus anthracis, B. cereus and Bacillus thuringiensis. These phages belong to the Myoviridae, Siphoviridae, Podoviridae and Tectiviridae families. For the sake of clarity, several phage categories have been made according to significant characteristics such as lifestyles and lysogenic states. The main categories comprise the transducing phages, phages with a chromosomal or plasmidial prophage state, γ-like phages and jumbo-phages. The current genomic characterization of some of these phages is also addressed throughout this work and some promising applications are discussed here. PMID:25010767

  11. Phages preying on Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis: past, present and future.

    PubMed

    Gillis, Annika; Mahillon, Jacques

    2014-07-01

    Many bacteriophages (phages) have been widely studied due to their major role in virulence evolution of bacterial pathogens. However, less attention has been paid to phages preying on bacteria from the Bacillus cereus group and their contribution to the bacterial genetic pool has been disregarded. Therefore, this review brings together the main information for the B. cereus group phages, from their discovery to their modern biotechnological applications. A special focus is given to phages infecting Bacillus anthracis, B. cereus and Bacillus thuringiensis. These phages belong to the Myoviridae, Siphoviridae, Podoviridae and Tectiviridae families. For the sake of clarity, several phage categories have been made according to significant characteristics such as lifestyles and lysogenic states. The main categories comprise the transducing phages, phages with a chromosomal or plasmidial prophage state, γ-like phages and jumbo-phages. The current genomic characterization of some of these phages is also addressed throughout this work and some promising applications are discussed here. PMID:25010767

  12. Genetic differentiation between sympatric populations of Bacillus cereus and Bacillus thuringiensis.

    PubMed

    Vilas-Boas, Gislayne; Sanchis, Vincent; Lereclus, Didier; Lemos, Manoel Victor F; Bourguet, Denis

    2002-03-01

    Little is known about genetic exchanges in natural populations of bacteria of the spore-forming Bacillus cereus group, because no population genetics studies have been performed with local sympatric populations. We isolated strains of Bacillus thuringiensis and B. cereus from small samples of soil collected at the same time from two separate geographical sites, one within the forest and the other at the edge of the forest. A total of 100 B. cereus and 98 B. thuringiensis strains were isolated and characterized by electrophoresis to determine allelic composition at nine enzymatic loci. We observed genetic differentiation between populations of B. cereus and B. thuringiensis. Populations of a given Bacillus species--B. thuringiensis or B. cereus--were genetically more similar to each other than to populations of the other Bacillus species. Hemolytic activity provided further evidence of this genetic divergence, which remained evident even if putative clones were removed from the data set. Our results suggest that the rate of gene flow was higher between strains of the same species, but that exchanges between B. cereus and B. thuringiensis were nonetheless possible. Linkage disequilibrium analysis revealed sufficient recombination for B. cereus populations to be considered panmictic units. In B. thuringiensis, the balance between clonal proliferation and recombination seemed to depend on location. Overall, our data indicate that it is not important for risk assessment purposes to determine whether B. cereus and B. thuringiensis belong to a single or two species. Assessment of the biosafety of pest control based on B. thuringiensis requires evaluation of the extent of genetic exchange between strains in realistic natural conditions. PMID:11872495

  13. Genetic Differentiation between Sympatric Populations of Bacillus cereus and Bacillus thuringiensis

    PubMed Central

    Vilas-Boas, Gislayne; Sanchis, Vincent; Lereclus, Didier; Lemos, Manoel Victor F.; Bourguet, Denis

    2002-01-01

    Little is known about genetic exchanges in natural populations of bacteria of the spore-forming Bacillus cereus group, because no population genetics studies have been performed with local sympatric populations. We isolated strains of Bacillus thuringiensis and B. cereus from small samples of soil collected at the same time from two separate geographical sites, one within the forest and the other at the edge of the forest. A total of 100 B. cereus and 98 B. thuringiensis strains were isolated and characterized by electrophoresis to determine allelic composition at nine enzymatic loci. We observed genetic differentiation between populations of B. cereus and B. thuringiensis. Populations of a given Bacillus species—B. thuringiensis or B. cereus—were genetically more similar to each other than to populations of the other Bacillus species. Hemolytic activity provided further evidence of this genetic divergence, which remained evident even if putative clones were removed from the data set. Our results suggest that the rate of gene flow was higher between strains of the same species, but that exchanges between B. cereus and B. thuringiensis were nonetheless possible. Linkage disequilibrium analysis revealed sufficient recombination for B. cereus populations to be considered panmictic units. In B. thuringiensis, the balance between clonal proliferation and recombination seemed to depend on location. Overall, our data indicate that it is not important for risk assessment purposes to determine whether B. cereus and B. thuringiensis belong to a single or two species. Assessment of the biosafety of pest control based on B. thuringiensis requires evaluation of the extent of genetic exchange between strains in realistic natural conditions. PMID:11872495

  14. Molecular characterization and genetic diversity of insecticidal crystal protein genes in native Bacillus thuringiensis isolates.

    PubMed

    Mahadeva Swamy, H M; Asokan, R; Mahmood, Riaz; Nagesha, S N

    2013-04-01

    The Western Ghats of Karnataka natural ecosystem are among the most diverse and is one of the eight hottest hotspots of biological diversity in the world, that runs along the western part of India through four states including Karnataka. Bacillus thuringiensis (Bt) strains were isolated from soils of Western Ghats of Karnataka and characterized by molecular and analytical methods as a result of which 28 new Bt-like isolates were identified. Bt strains were isolated from soil samples using sodium acetate selection method. The morphology of crystals was studied using light and phase contrast microscopy. Isolates were further characterized for insecticidal cry gene by PCR, composition of toxins in bacterial crystals by SDS-PAGE cloning, sequencing and evaluation of toxicity was done. As a result 28 new Bt-like isolates were identified. Majority of the isolates showed the presence of a 55 kDa protein bands on SDS-PAGE while the rest showed 130, 73, 34, and 25 kDa bands. PCR analysis revealed predominance of Coleopteran-active cry genes in these isolates. The variations in the nucleotide sequences, crystal morphology, and mass of crystal protein(s) purified from the Bt isolates revealed genetic and molecular diversity. Three strains containing Coleopteran-active cry genes showed higher activity against larvae Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) than B. thuringiensis subsp. Morrisoni. Results indicated that Bt isolates could be utilized for bioinsecticide production, aiming to reduce the use of chemical insecticide which could be useful to use in integrated pest management to control agriculturally important pests for sustainable crop production. PMID:23207696

  15. Occurrence of Bacillus thuringiensis in fresh waters of Japan.

    PubMed

    Ichimatsu, T; Mizuki, E; Nishimura, K; Akao, T; Saitoh, H; Higuchi, K; Ohba, M

    2000-04-01

    Bacillus thuringiensis was recovered at a relatively high frequency from both running and still fresh waters in natural environments of Kyushu, Japan. Of 107 water samples examined, 53 (49.5%) contained this organism. The frequency of B. thuringiensis colonies was 4.4% among 4414 colonies of the Bacillus cereus/B. thuringiensis group. The density of this bacterium in fresh waters averaged 0.45 cfu/ml. Serologically, B. thuringiensis isolates were assigned to 26 H serotypes. Of these, H14/36 (H serovar israelensis/malaysiensis) was the predominant, followed by the serotypes H3abc (kurstaki), H27 (mexicanensis), H3ad (sumiyoshiensis), and H35 (seoulensis). Of 195 isolates, 52 (26.7%) exhibited larvicidal activity against aquatic Diptera; 21 killed Culex pipiens molestus (Culicidae) only, and 31 were active on both the culicine mosquito and the moth-fly, Clogmia albipunctata (Psychodidae). The Diptera-toxic isolates produced spherical or irregularly pointed parasporal inclusions. PMID:10688688

  16. Photoprotection of Bacillus thuringiensis kurstaki from ultraviolet irradiation

    SciTech Connect

    Cohen, E.; Rozen, H.; Joseph, T.; Braun, S.; Margulies, L. )

    1991-05-01

    Irradiation of Bacillus thuringiensis var. kurstaki HD1 at 300-350 nm for up to 12 hr using a photochemical reactor results in a rapid loss of its toxicity to larvae of Heliothis armigera. Photoprotection of the toxic component was obtained by adsorption of cationic chromophores such as acriflavin (AF), methyl green, and rhodamine B to B. thuringiensis. AF gave the best photoprotection and a level of 0.42 mmol/g dye absorbed per gram of B. thuringiensis was highly toxic even after 12 hr of ultraviolet (uv) irradiation as compared to the control (77.5 and 5% of insect mortality, respectively). Ultraviolet and Fourier-transform infrared spectroscopic studies indicate molecular interactions between B. thuringiensis and AF. The nature of these interactions and energy or charge transfer as possible mechanisms of photoprotection are discussed. It is speculated that tryptophan residues are essential for the toxic effect of B. thuringiensis. It is suggested that photoprotection is attained as energy is transferred from the excited tryptophan moieties to the chromophore molecules.

  17. SinR Controls Enterotoxin Expression in Bacillus thuringiensis Biofilms

    PubMed Central

    Økstad, Ole-Andreas; Verplaetse, Emilie; Gilois, Nathalie; Bennaceur, Imène; Perchat, Stéphane; Gominet, Myriam; Aymerich, Stéphane; Kolstø, Anne-Brit; Lereclus, Didier; Gohar, Michel

    2014-01-01

    The entomopathogen Bacillus thuringiensis produces dense biofilms under various conditions. Here, we report that the transition phase regulators Spo0A, AbrB and SinR control biofilm formation and swimming motility in B. thuringiensis, just as they control biofilm formation and swarming motility in the closely related saprophyte species B. subtilis. However, microarray analysis indicated that in B. thuringiensis, in contrast to B. subtilis, SinR does not control an eps operon involved in exopolysaccharides production, but regulates genes involved in the biosynthesis of the lipopeptide kurstakin. This lipopeptide is required for biofilm formation and was previously shown to be important for survival in the host cadaver (necrotrophism). Microarray analysis also revealed that the SinR regulon contains genes coding for the Hbl enterotoxin. Transcriptional fusion assays, Western blots and hemolysis assays confirmed that SinR controls Hbl expression, together with PlcR, the main virulence regulator in B. thuringiensis. We show that Hbl is expressed in a sustained way in a small subpopulation of the biofilm, whereas almost all the planktonic population transiently expresses Hbl. The gene coding for SinI, an antagonist of SinR, is expressed in the same biofilm subpopulation as hbl, suggesting that hbl transcription heterogeneity is SinI-dependent. B. thuringiensis and B. cereus are enteric bacteria which possibly form biofilms lining the host intestinal epithelium. Toxins produced in biofilms could therefore be delivered directly to the target tissue. PMID:24498128

  18. Genome Sequence of the Endophytic Bacterium Bacillus thuringiensis Strain KB1, a Potential Biocontrol Agent against Phytopathogens

    PubMed Central

    Jo, Sung Hee; Hong, Chi Eun

    2016-01-01

    Bacillus thuringiensis is the most widely known microbial pesticide used in agricultural applications. Herein, we report a draft genome sequence of the endophytic bacterium Bacillus thuringiensis strain KB1, which exhibits antagonism against phytopathogens. PMID:27103716

  19. Identification and characterization of the Sudanese Bacillus thuringiensis and related bacterial strains for their efficacy against Helicoverpa armigera and Tribolium castaneum.

    PubMed

    Gorashi, N E; Tripathi, M; Kalia, V; Gujar, G T

    2014-06-01

    Forty-four isolates of Bacillus thuringiensis like bacteria from various sources in different locations from Sudan were tested for their insecticidal activity. The toxicity of these isolates ranged from 6.6 to 70% to the neonates of cotton bollworm, Helicoverpa armigera at 10 ppm concentration. The most effective ones are Kb-29, St-6 and Wh-1 comparable with HD-1. Toxicity of isolates to larvae of the red flour beetle, Tribolium castaneum ranged from 20 to 100%. Isolates St-2 and St-23 gave 100% larval mortality within 15 days of exposure and were at par with Ab-8, Ab-12, Kb-26, Kb-30, Om-4, Po-2, Po-5, Po-7, Sa-8 and Wh-5 and were also comparable with E. coli clone expressing Cry3 toxin. The most effective five isolates viz., Kb-29, St-2, St-6, St-23 and Wh-1 belonged to B. thuringiensis. The St-6 isolate, which also showed high toxicity to T. castaneum larvae, had cry1 genes along with coleopteran active cry28 genes, but not cry3 genes. Of the 25 isolates characterized with 16s DNA sequencing, seven belonged to Paenibacillus spp., one Lysinibacillus sphaericus, one Bacillus pumilus, four Bacillus spp., and rest 12 belonged to B. thuringiensis. Biochemical characterization in each species showed variation. The present study shows potential of some isolates like Kb-29, St-2, St-6, St-23 and Wh-1 as promising bioinsecticides. PMID:24956895

  20. [Bioconversion of sewage sludge to biopesticide by Bacillus thuringiensis].

    PubMed

    Chang, Ming; Zhou, Shun-gui; Lu, Na; Ni, Jin-ren

    2006-07-01

    Feasibility of bioconversion of sewage sludge to biopesticide by Bacillus thuringiensis was studied using sewage sludge as a raw material. The fermentation was also compared with conventional medium. Results showed that without any pretreatment, the nutrients contained in sewage sludge were almost sufficient for Bacillus thuringiensis growth, even with a rapid multiplicational rate. Higher viable cells and viable spores values were obtained earlier at 24 h, with 9.48 x 10(8) CFU x mL(-1) and 8.51 x 10(8) CFU x mL(-1) respectively, which was 12 hours earlier and nearly 20 percent higher than conventional medium. SEM of 36 h samples gave a clear phenomenon that the metabolizability in sludge was much faster with spores and crystals spreading around. The crystals in sludge seemed rather bigger and more regular. Also a better crystal protein yield of 2.80 mg x mL(-1) was observed in sludge medium compared to conventional medium at the end of fermentation. Sludge fermentation for Bacillus thuringiensis reduces the producing cost, and gives better fermentation capabilities. It's expected to be a new method for sludge disposal. PMID:16881328

  1. 40 CFR 174.509 - Bacillus thuringiensis Cry3A protein; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Cry3A protein...-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.509 Bacillus thuringiensis Cry3A protein; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry3A protein are...

  2. 40 CFR 174.504 - Bacillus thuringiensis Cry1F protein; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacillus thuringiensis Cry1F protein...-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.504 Bacillus thuringiensis Cry1F protein; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1F protein in the...

  3. 40 CFR 174.509 - Bacillus thuringiensis Cry3A protein; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacillus thuringiensis Cry3A protein...-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.509 Bacillus thuringiensis Cry3A protein; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry3A protein are...

  4. 40 CFR 174.509 - Bacillus thuringiensis Cry3A protein; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Cry3A protein...-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.509 Bacillus thuringiensis Cry3A protein; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry3A protein are...

  5. 40 CFR 174.509 - Bacillus thuringiensis Cry3A protein; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Cry3A protein...-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.509 Bacillus thuringiensis Cry3A protein; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry3A protein are...

  6. SR450 and Superhawk XP applications of Bacillus thuringiensis israelensis de Barjac against Culex quinquefasciatus Say

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sprayer comparisons and larval morality assays were conducted following SR450 backpack mist blower and Superhawk XP thermal fogger applications of Vectobac® WDG Bacillus thuringiensis israelensis (Bti) de Barjac against Culex quinquefasciatus Say. Bacillus thuringiensis israelensis was applied at m...

  7. Midgut microbiota and host immunocompetence underlie Bacillus thuringiensis killing mechanism.

    PubMed

    Caccia, Silvia; Di Lelio, Ilaria; La Storia, Antonietta; Marinelli, Adriana; Varricchio, Paola; Franzetti, Eleonora; Banyuls, Núria; Tettamanti, Gianluca; Casartelli, Morena; Giordana, Barbara; Ferré, Juan; Gigliotti, Silvia; Ercolini, Danilo; Pennacchio, Francesco

    2016-08-23

    Bacillus thuringiensis is a widely used bacterial entomopathogen producing insecticidal toxins, some of which are expressed in insect-resistant transgenic crops. Surprisingly, the killing mechanism of B. thuringiensis remains controversial. In particular, the importance of the septicemia induced by the host midgut microbiota is still debated as a result of the lack of experimental evidence obtained without drastic manipulation of the midgut and its content. Here this key issue is addressed by RNAi-mediated silencing of an immune gene in a lepidopteran host Spodoptera littoralis, leaving the midgut microbiota unaltered. The resulting cellular immunosuppression was characterized by a reduced nodulation response, which was associated with a significant enhancement of host larvae mortality triggered by B. thuringiensis and a Cry toxin. This was determined by an uncontrolled proliferation of midgut bacteria, after entering the body cavity through toxin-induced epithelial lesions. Consequently, the hemolymphatic microbiota dramatically changed upon treatment with Cry1Ca toxin, showing a remarkable predominance of Serratia and Clostridium species, which switched from asymptomatic gut symbionts to hemocoelic pathogens. These experimental results demonstrate the important contribution of host enteric flora in B. thuringiensis-killing activity and provide a sound foundation for developing new insect control strategies aimed at enhancing the impact of biocontrol agents by reducing the immunocompetence of the host. PMID:27506800

  8. Bacillus thuringiensis membrane-damaging toxins acting on mammalian cells.

    PubMed

    Celandroni, Francesco; Salvetti, Sara; Senesi, Sonia; Ghelardi, Emilia

    2014-12-01

    Bacillus thuringiensis is widely used as a biopesticide in forestry and agriculture, being able to produce potent species-specific insecticidal toxins and considered nonpathogenic to other animals. More recently, however, repeated observations are documenting the association of this microorganism with various infectious diseases in humans, such as food-poisoning-associated diarrheas, periodontitis, bacteremia, as well as ocular, burn, and wound infections. Similar to B. cereus, B. thuringiensis produces an array of virulence factors acting against mammalian cells, such as phosphatidylcholine- and phosphatidylinositol-specific phospholipase C (PC-PLC and PI-PLC), hemolysins, in particular hemolysin BL (HBL), and various enterotoxins. The contribution of some of these toxins to B. thuringiensis pathogenicity has been studied in animal models of infection, following intravitreous, intranasal, or intratracheal inoculation. These studies lead to the speculation that the activities of PC-PLC, PI-PLC, and HBL are responsible for most of the pathogenic properties of B. thuringiensis in nongastrointestinal infections in mammals. This review summarizes data regarding the biological activity, the genetic basis, and the structural features of these membrane-damaging toxins. PMID:25283838

  9. Microbial control and biotechnology research on Bacillus thuringiensis in China.

    PubMed

    Huang, Da-Fang; Zhang, Jie; Song, Fu-Ping; Lang, Zhi-Hong

    2007-07-01

    The current status of production and application of biopesticides for pest control in China is briefly reviewed, with a focus on research advances in microbial control with Bacillus thuringiensis (Bt). These have led to improvements in Bt production, exploitation of Bt gene resources, and development of engineered Bt insecticides and transgenic Bt crops that have expanded host ranges and increased efficacy against target pests. Both conventional and biotechnology approaches need to be employed to achieve further progress in discovery, production technology, formulation processing, development of quality standards and recommended use patterns. PMID:17481651

  10. Insecticidal proteins from Bacillus thuringiensis protect corn from corn rootworms.

    PubMed

    Moellenbeck, D J; Peters, M L; Bing, J W; Rouse, J R; Higgins, L S; Sims, L; Nevshemal, T; Marshall, L; Ellis, R T; Bystrak, P G; Lang, B A; Stewart, J L; Kouba, K; Sondag, V; Gustafson, V; Nour, K; Xu, D; Swenson, J; Zhang, J; Czapla, T; Schwab, G; Jayne, S; Stockhoff, B A; Narva, K; Schnepf, H E; Stelman, S J; Poutre, C; Koziel, M; Duck, N

    2001-07-01

    Field tests of corn co-expressing two new delta-endotoxins from Bacillus thuringiensis (Bt) have demonstrated protection from root damage by western corn rootworm (Diabrotica virgifera virgifera LeConte). The level of protection exceeds that provided by chemical insecticides. In the bacterium, these proteins form crystals during the sporulation phase of the growth cycle, are encoded by a single operon, and have molecular masses of 14 kDa and 44 kDa. Corn rootworm larvae fed on corn roots expressing the proteins showed histopathological symptoms in the midgut epithelium. PMID:11433280

  11. Bacillus thuringiensis resistance in Plutella - too many trees?

    PubMed

    Crickmore, Neil

    2016-06-01

    Plutella xylostella was the first insect for which resistance to Bacillus thuringiensis was reported in the field, yet despite many studies on the nature of this resistance phenotype its genetic and molecular basis remains elusive. Many different factors have been proposed as contributing to resistance, although in many cases it has not been possible to establish a causal link. Indeed, there are so many studies published that it has become very difficult to 'see the wood for the trees'. This article will attempt to clarify our current understanding of Bt resistance in P. xylostella and consider the criteria that are used when validating a particular model. PMID:27436736

  12. Existence of lysogenic bacteriophages in Bacillus thuringiensis type strains.

    PubMed

    Roh, Jong Yul; Park, Jong Bin; Liu, Qin; Kim, Song Eun; Tao, Xueying; Choi, Tae Woong; Choi, Jae Young; Kim, Woo Jin; Jin, Byung Rae; Je, Yeon Ho

    2013-07-01

    We screened the existence of bacteriophages in 67 Bacillus thuringiensis type strains by phage DNA extraction and PCR using phage terminase small subunit (TerS)-specific primers to the supernatants and the precipitated pellets of Bt cultures, and by transmission electron microscopy. The various bacteriophages were observed from the supernatants of 22 type strains. Ten type strains showed the extracted phage DNAs and the amplified fragment by TerS PCR but 12 type strains showed only the phage DNAs. Their morphological characteristic suggests that they belong to Family Siphoviridae which had a long tail and symmetrical head. PMID:23632013

  13. Complete sequence of three plasmids from Bacillus thuringiensis INTA-FR7-4 environmental isolate and comparison with related plasmids from the Bacillus cereus group.

    PubMed

    Amadio, Ariel F; Benintende, Graciela B; Zandomeni, Rubén O

    2009-11-01

    Bacillus thuringiensis is an insect pathogen used worldwide as a bioinsecticide. It belongs to the Bacillus cereus sensu lato group as well as Bacillus anthracis and B. cereus. Plasmids from this group of organisms have been implicated in pathogenicity as they carry the genes responsible for different types of diseases that affect mammals and insects. Some plasmids, like pAW63 and pBT9727, encode a functional conjugation machinery allowing them to be transferred to a recipient cell. They also share extensive homology with the non-functional conjugation apparatus of pXO2 from B. anthracis. In this study we report the complete sequence of three plasmids from an environmental B. thuringiensis isolate from Argentina, obtained by a shotgun sequencing method. We obtained the complete nucleotide sequence of plasmids pFR12 (12,095bp), pFR12.5 (12,459bp) and pFR55 (55,712bp) from B. thuringiensis INTA-FR7-4. pFR12 and pFR12.5 were classified as cryptic as they do not code for any obvious functions besides replication and mobilization. Both small plasmids were classified as RCR plasmids due to similarities with the replicases they encode. Plasmid pFR55 showed a structural organization similar to that observed for plasmids pAW63, pBT9727 and pXO2. pFR55 also shares a tra region with these plasmids, containing genes related to T4SS and conjugation. A comparison between pFR55 and conjugative plasmids led to the postulation that pFR55 is a conjugative plasmid. Genes related to replication functions in pFR55 are different to those described for plasmids with known complete sequences. pFR55 is the first completely sequenced plasmid with a replication machinery related to that of ori44. The analysis of the complete sequence of plasmids from an environmental isolate of B. thuringiensis permitted the identification of a near complete conjugation apparatus in pFR55, resembling those of plasmids pAW63, pBT9727 and pXO2. The availability of this sequence is a step forward in the study

  14. Isolation and molecular characterisation of alkaline protease producing Bacillus thuringiensis.

    PubMed

    Agasthya, Annapurna S; Sharma, Naresh; Mohan, Anand; Mahal, Prabhpreet

    2013-05-01

    Proteases are of particular interest because of their action on insoluble keratin substrates and generally on a broad range of protein substrates. Proteases are one of the most important groups of industrial enzymes used in detergent, protein, brewing, meat, photographic, leather, dairy, pharmaceutical and food industry. In the present study, the organism isolated from the protein rich soil sample was identified by biochemical and molecular characterisation as Bacillus thuringiensis and further optimum conditions for alkaline protease synthesis were determined. The growth conditions for B. thuringiensis was optimised by inoculating into yeast extract casein medium at different pH and incubating at different temperatures. The maximum protease production occurred at pH 8 and at 37 °C. B. thuringiensis showed proteolytic activity at various culture conditions. Optimum conditions for the protease activity were found to be 47 °C and pH 8. In the later stage, the blood removing action of crude and partially purified protease was found to be effective within 25 min in the presence of commercial detergents indicating the possible use of this enzyme in detergent industry. Enzyme also showed good activity against hair substrate keratin and can be used for dehairing. PMID:22826099

  15. Modified Bacillus thuringiensis Toxins and a Hybrid B. thuringiensis Strain Counter Greenhouse-Selected Resistance in Trichoplusia ni▿

    PubMed Central

    Franklin, Michelle T.; Nieman, Christal L.; Janmaat, Alida F.; Soberón, Mario; Bravo, Alejandra; Tabashnik, Bruce E.; Myers, Judith H.

    2009-01-01

    Resistance of greenhouse-selected strains of the cabbage looper, Trichoplusia ni, to Bacillus thuringiensis subsp. kurstaki was countered by a hybrid strain of B. thuringiensis and genetically modified toxins Cry1AbMod and Cry1AcMod, which lack helix α-1. Resistance to Cry1AbMod and Cry1AcMod was >100-fold less than resistance to native toxins Cry1Ab and Cry1Ac. PMID:19592525

  16. 40 CFR 174.530 - Bacillus thuringiensis Cry2Ae protein in cotton; temporary exemption from the requirement of a...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Cry2Ae protein... thuringiensis Cry2Ae protein in cotton; temporary exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry2Ae protein in or on the food commodities of cotton, cotton; cotton,...

  17. Two novel strains of Bacillus thuringiensis toxic to coleopterans.

    PubMed Central

    Rupar, M J; Donovan, W P; Groat, R G; Slaney, A C; Mattison, J W; Johnson, T B; Charles, J F; Dumanoir, V C; de Barjac, H

    1991-01-01

    Two novel strains of Bacillus thuringiensis were isolated from native habitats by the use of genes coding for proteins toxic to coleopterans (cryIII genes) as hybridization probes. Strain EG2838 (isolated by the use of the cryIIIA probe) contained a cryIIIA-hybridizing plasmid of approximately 100 MDa and synthesized crystal proteins of approximately 200 (doublet), 74, 70, 32, and 28 kDa. Strain EG4961 (isolated by the use of a cryIIIA-related probe) contained a cryIIIA-hybridizing plasmid of approximately 95 MDa and synthesized crystal proteins of 74, 70, and 30 kDa. Structural relationships among the crystal proteins of strains EG2838 and EG4961 were detected; antibodies to the CryIIIA protein toxic to coleopterans reacted with the 74- and 70-kDa proteins of EG2838 and EG4961, antibodies to the 32-kDa plus 28-kDa proteins of EG2838 reacted with the 30-kDa protein of EG4961, and antibodies to the 200-kDa proteins of EG2838 reacted with the 28-kDa protein of EG2838. Experiments with B. thuringiensis flagella antibody reagents demonstrated that EG2838 belongs to H serotype 9 (reference strain B. thuringiensis subsp. tolworthi) and that EG4961 belongs to H serotype 18 (reference strain B. thuringiensis subsp. kumamotoensis). A mixture of spores plus crystal proteins of either EG2838 or EG4961 was toxic to the larvae of Colorado potato beetle (Leptinotarsa decemlineata), and significantly, the EG4961 mixture was also toxic to the larvae of southern corn rootworm (Diabrotica undecimpunctata howardi). DNA restriction blot analysis suggested that strains EG2838 and EG4961 each contained a unique gene coding for a protein toxic to coleopterans. Images PMID:1781691

  18. Two novel strains of Bacillus thuringiensis toxic to coleopterans.

    PubMed

    Rupar, M J; Donovan, W P; Groat, R G; Slaney, A C; Mattison, J W; Johnson, T B; Charles, J F; Dumanoir, V C; de Barjac, H

    1991-11-01

    Two novel strains of Bacillus thuringiensis were isolated from native habitats by the use of genes coding for proteins toxic to coleopterans (cryIII genes) as hybridization probes. Strain EG2838 (isolated by the use of the cryIIIA probe) contained a cryIIIA-hybridizing plasmid of approximately 100 MDa and synthesized crystal proteins of approximately 200 (doublet), 74, 70, 32, and 28 kDa. Strain EG4961 (isolated by the use of a cryIIIA-related probe) contained a cryIIIA-hybridizing plasmid of approximately 95 MDa and synthesized crystal proteins of 74, 70, and 30 kDa. Structural relationships among the crystal proteins of strains EG2838 and EG4961 were detected; antibodies to the CryIIIA protein toxic to coleopterans reacted with the 74- and 70-kDa proteins of EG2838 and EG4961, antibodies to the 32-kDa plus 28-kDa proteins of EG2838 reacted with the 30-kDa protein of EG4961, and antibodies to the 200-kDa proteins of EG2838 reacted with the 28-kDa protein of EG2838. Experiments with B. thuringiensis flagella antibody reagents demonstrated that EG2838 belongs to H serotype 9 (reference strain B. thuringiensis subsp. tolworthi) and that EG4961 belongs to H serotype 18 (reference strain B. thuringiensis subsp. kumamotoensis). A mixture of spores plus crystal proteins of either EG2838 or EG4961 was toxic to the larvae of Colorado potato beetle (Leptinotarsa decemlineata), and significantly, the EG4961 mixture was also toxic to the larvae of southern corn rootworm (Diabrotica undecimpunctata howardi). DNA restriction blot analysis suggested that strains EG2838 and EG4961 each contained a unique gene coding for a protein toxic to coleopterans. PMID:1781691

  19. Architecture and High-Resolution Structure of Bacillus thuringiensis and Bacillus cereus Spore Coat Surfaces

    SciTech Connect

    Plomp, M; Leighton, T; Wheeler, K; Malkin, A

    2005-02-18

    We have utilized atomic force microscopy (AFM) to visualize the native surface topology and ultrastructure of Bacillus thuringiensis and Bacillus cereus spores in water and in air. AFM was able to resolve the nanostructure of the exosporium and three distinctive classes of appendages. Removal of the exosporium exposed either a hexagonal honeycomb layer (B. thuringiensis) or a rodlet outer spore coat layer (B. cereus). Removal of the rodlet structure from B. cereus spores revealed an underlying honeycomb layer similar to that observed with B. thuringiensis spores. The periodicity of the rodlet structure on the outer spore coat of B. cereus was {approx}8 nm, and the length of the rodlets was limited to the cross-patched domain structure of this layer to {approx}200 nm. The lattice constant of the honeycomb structures was {approx}9 nm for both B. cereus and B. thuringiensis spores. Both honeycomb structures were composed of multiple, disoriented domains with distinct boundaries. Our results demonstrate that variations in storage and preparation procedures result in architectural changes in individual spore surfaces, which establish AFM as a useful tool for evaluation of preparation and processing ''fingerprints'' of bacterial spores. These results establish that high-resolution AFM has the capacity to reveal species-specific assembly and nanometer scale structure of spore surfaces. These species-specific spore surface structural variations are correlated with sequence divergences in a spore core structural protein SspE.

  20. Activity of Bacillus thuringiensis against Pryeria sinica(Lepidoptera: Zygaenidae), an invasive pest of Euonymus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pryeria sinica Moore (Lepidoptera: Zygaenidae), an invasive pest of Euonymus, is susceptible in the second instar to the Bacillus thuringiensis Berliner product Thuricide®, and to several strains isolated from other B. thuringiensis products. Third instars are also susceptible, while susceptibility...

  1. Survival of diverse bacillus thuringiensis strains in gypsy moth (Lepidotera: Lymantriidae) is correlated with urease production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacillus thuringiensis is an entomopathogenic bacterium that can kill a variety of pest insects, but seldom causes epizootics because it replicates poorly in insects. By attempting to repeatedly pass lepidopteran-active B. thuringiensis strains through gypsy moth larvae, we found that only those str...

  2. CHARACTERIZATION OF THE MAMMALIAN TOXICITY OF THE CRYSTAL POLYPEPTIDES OF BACILLUS THURINGIENSIS SUBSPECIES ISRAELENSIS

    EPA Science Inventory

    Solubilized crystal polypeptide preparations of Bacillus thuringiensis subsp. israelertsis (BTI) were fractionated by immunoaffinity chromatography using a bound monoclonal antibody formed against the 28K crystal polypeptide. The 28K polypeptide was confirmed to be hemolytic and ...

  3. 40 CFR 180.1011 - Viable spores of the microorganism Bacillus thuringiensis Berliner; exemption from the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... production is a Bacillus thuringiensis strain which does not produce β-exotoxin under standard manufacturing... it is applied either to growing crops, or when it is applied after harvest in accordance with...

  4. Pathogenicity of Bacillus thuringiensis variety kurstaki to Ixodes scapularis (Acari: Ixodidae)

    USGS Publications Warehouse

    Zhioua, E.; Heyer, K.; Browning, M.; Ginsberg, H.S.; LeBrun, R.A.

    1999-01-01

    Pathogenicity of the entomopathogenic bacterium Bacillus thuringiensis var. kurstaki de Barjac & Lemille was tested against the black-legged tick, Ixodes scapularis Say. Engorged larvae dipped in a solution of 108 spores per ml showed 96% mortality, 3 wk post-infection. The LC50 value for engorged larvae (concentration required to kill 50% of ticks) was 107 spores/ml. Bacillus thuringiensis shows considerable potential as a microbial control agent for the management of Ixodes scapularis.

  5. A strategy for shuffling numerous Bacillus thuringiensis crystal protein domains.

    PubMed

    Knight, Jacqueline S; Broadwell, Andrew H; Grant, Warwick N; Shoemaker, Charles B

    2004-12-01

    Bacillus thuringiensis that produce Cry1Ba are toxic to Lucilia cuprina Wiedemann blow fly maggots in vivo, and when applied in quantity to sheep fleece, provide up to 6 wk protection against flystrike in the field. These strains also are toxic to Epiphyas postvittana (Walker) light brown apple moth caterpillars. B. thuringiensis expressing Cry1Db are toxic only to E. postvittana. When Cry1Ba and Cry1Db proteins are expressed within Escherichia coli, the recombinant bacteria have the same toxicity profile as the wild-type B. thuringiensis strain. In an effort to develop a Cry protein with improved blow fly toxicity, three different internal regions of Cry1Ba coding DNA, encoding all or part of domains I, II and III respectively were systematically exchanged with the corresponding region from a pool of other Cry protein coding DNAs. The chimeric products were then expressed in recombinant E. coli, and the resulting bacteria assayed for toxicity on L. cuprina and E. postvittana. Clones having insecticide bioactivity were characterized to identify the source of the replacement Cry domain. Despite successfully expressing a large number and variety of chimeric proteins within E. coli, many with measurable insecticidal activity, none of the chimeras had greater potency against L. cuprina than the wild-type Cry1Ba. Chimeric replacements involving domains I and II were rarely active, whereas a much higher proportion of domain III chimeras had some bioactivity. We conclude that shuffling of Cry coding regions through joining at the major conserved sequence motifs is an effective means for the production of a diverse number of chimeric Cry proteins but that such toxins with enhanced bioactive properties will be rare or nonexistent. PMID:15666731

  6. Production of Polyhydroxyalkanoate Co-polymer by Bacillus thuringiensis.

    PubMed

    Singh, Mamtesh; Kumar, Prasun; Patel, Sanjay K S; Kalia, Vipin C

    2013-03-01

    Integrative processes for the production of bioenergy and biopolymers are gaining importance in recent years as alternatives to fossil fuels and synthetic plastics. In the present study, Bacillus thuringiensis strain EGU45 has been used to generate hydrogen (H2), polyhydroxybutyrate (PHB) and new co-polymers (NP). Under batch culture conditions with 250 ml synthetic media, B. thuringiensis EGU45 produced up to 0.58 mol H2/mol of glucose. Effluent from the H2 production stage was incubated under shaking conditions leading to the production of PHB up to 95 mg/l along with NP of levulinic acid up to 190 mg/l. A twofold to fourfold enhancement in PHB and up to 1.5 fold increase in NP yields was observed on synthetic medium (mixture of M-9+GM-2 medium in 1:1 ratio) containing at 1-2 % glucose concentration. The novelty of this work lies in developing modified physiological conditions, which induce bacterial culture to produce NP. PMID:24426082

  7. Glucose induced fractal colony pattern of Bacillus thuringiensis.

    PubMed

    Roy, Manas K; Banerjee, Paromita; Sengupta, Tapas K; Dattagupta, Sushanta

    2010-08-01

    Growing colonies of bacteria on the surface of thin agar plates exhibit fractal patterns as a result of nonlinear response to environmental conditions, such as nutrients, solidity of the agar medium and temperature. Here, we examine the effect of glucose on pattern formation by growing colonies of Bacillus thuringiensis isolate KPWP1. We also present the theoretical modeling of the colony growth of KPWP1 and the associated spatio-temporal patterns. Our experimental results are in excellent agreement with simulations based on a reaction-diffusion model that describes diffusion-limited aggregation and branching, in which individual cells move actively in the periphery, but become immotile in the inner regions of the growing colony. We obtain the Hausdorff fractal dimension of the colony patterns: D(H.Expt)=1.1969 and D(H, R.D.=)1.1965, for experiment and reaction-diffusion model, respectively. Results of our experiments and modeling clearly show how glucose at higher concentration can prove to be inhibitory for motility of growing colonies of B. thuringiensis cells on semisolid support and be responsible for changes in the growth pattern. PMID:20553734

  8. Bacillus thuringiensis: a specific gamma-cyclodextrin producer strain.

    PubMed

    Goo, Bon Geun; Hwang, You Jin; Park, Jae Kweon

    2014-03-11

    An anaerobic microbial isolate Bacillus species, designated B. thuringiensis GU-2, was isolated from soil as a specific γ-cyclodextrin (CD) producer strain in alkaline medium under anaerobic conditions. The optimum pH and temperature for bacterial growth and γ-CD production were estimated to be pH 8.5 and 37°C in the presence of 1.0% starch substrate, respectively. A high purity yield >95% of γ-CD from the total CD yield in the reaction mixture was obtained from starch that was supposed to be converted by gamma-cyclodextrin glycotransferase, tentatively named as γ-CGTase. The maximum γ-CGTase activity was estimated at 2.45U/mL under optimized condition. This is the first report demonstrating the generation of a specific γ-cyclodextrin (CD) producer strain by the action of a γ-CGTase under anaerobic conditions. PMID:24456970

  9. Novel fermentation media for production of Bacillus thuringiensis subsp. israelensis.

    PubMed

    Poopathi, Subbiah; Kumar, K Anup

    2003-08-01

    The production of Bacillus thuringiensis subsp. israelensis (deBarjac) (Bti) as a biopesticide is not cost-effective using existing fermentation technology. In this study, we explored the use of several less expensive alternative culture media (potato, common sugar, and Bengal gram) for the growth and production of Bti. Growth was obtained in all tested media and was comparable to that obtained in conventional medium (Luria-Bertani). Toxicity assays showed that the toxin produced from the novel growth media were effective in killing larvae of Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti and toxicity was comparable to that produced from Luria-Bertani medium. These observations suggest that potato can be used as a cheap source of culture medium for the production of Bti toxin in mosquito control programs. PMID:14503573

  10. Mode of action of mosquitocidal Bacillus thuringiensis toxins.

    PubMed

    Soberón, Mario; Fernández, Luisa E; Pérez, Claudia; Gill, Sarjeet S; Bravo, Alejandra

    2007-04-01

    Cry toxins from Bacillus thuringiensis (Bt) are used for insect control. Their primary action is to lyse midgut epithelial cells. In lepidopteran insects, Cry1A monomeric toxins interact with a first receptor and this interaction triggers toxin oligomerization. The oligomeric structure interacts then with a second GPI-anchored receptor that induces insertion into membrane microdomains and larvae death. In the case of mosquitocidal Bt strains, two different toxins participate, Cry and Cyt. These toxins have a synergistic effect and Cyt1Aa overcomes Cry toxin-resistance. We will summarize recent findings on the identification of Cry receptors in mosquitoes and the mechanism of synergism: Cyt1Aa synergizes or suppresses resistance to Cry toxins by functioning as a Cry membrane-bound receptor. PMID:17145072

  11. Nanoscale imaging of Bacillus thuringiensis flagella using atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Gillis, Annika; Dupres, Vincent; Delestrait, Guillaume; Mahillon, Jacques; Dufrêne, Yves F.

    2012-02-01

    Because bacterial flagella play essential roles in various processes (motility, adhesion, host interactions, secretion), studying their expression in relation to function is an important challenge. Here, we use atomic force microscopy (AFM) to gain insight into the nanoscale surface properties of two wild-type and four mutant strains of Bacillus thuringiensis exhibiting various levels of flagellation. We show that, unlike AFM in liquid, AFM in air is a simple and reliable approach to observe the morphological details of the bacteria, and to quantify the density and dimensions of their flagella. We found that the amount of flagella expressed by the six strains, as observed at the nanoscale, correlates with their microscopic swarming motility. These observations provide novel information on flagella expression in Gram-positive bacteria and demonstrate the power of AFM in genetic studies for the fast assessment of the phenotypic characteristics of bacterial strains altered in cell surface appendages.Because bacterial flagella play essential roles in various processes (motility, adhesion, host interactions, secretion), studying their expression in relation to function is an important challenge. Here, we use atomic force microscopy (AFM) to gain insight into the nanoscale surface properties of two wild-type and four mutant strains of Bacillus thuringiensis exhibiting various levels of flagellation. We show that, unlike AFM in liquid, AFM in air is a simple and reliable approach to observe the morphological details of the bacteria, and to quantify the density and dimensions of their flagella. We found that the amount of flagella expressed by the six strains, as observed at the nanoscale, correlates with their microscopic swarming motility. These observations provide novel information on flagella expression in Gram-positive bacteria and demonstrate the power of AFM in genetic studies for the fast assessment of the phenotypic characteristics of bacterial strains altered in

  12. Characterization of a highly toxic strain of Bacillus thuringiensis serovar kurstaki very similar to the HD-73 strain.

    PubMed

    Reinoso-Pozo, Yaritza; Del Rincón-Castro, Ma Cristina; Ibarra, Jorge E

    2016-09-01

    The LBIT-1200 strain of Bacillus thuringiensis was recently isolated from soil, and showed a 6.4 and 9.5 increase in toxicity, against Manduca sexta and Trichoplusia ni, respectively, compared to HD-73. However, LBIT-1200 was still highly similar to HD-73, including the production of bipyramidal crystals containing only one protein of ∼130 000 kDa, its flagellin gene sequence related to the kurstaki serotype, plasmid and RepPCR patterns similar to HD-73, no production of β-exotoxin and no presence of VIP genes. Sequencing of its cry gene showed the presence of a cry1Ac-type gene with four amino acid differences, including two amino acid replacements in domain III, compared to Cry1Ac1, which may explain its higher toxicity. In conclusion, the LBIT-1200 strain is a variant of the HD-73 strain but shows a much higher toxicity, which makes this new strain an important candidate to be developed as a bioinsecticide, once it passes other tests, throughout its biotechnological development. PMID:27535648

  13. Occurrence of Toxigenic Bacillus cereus and Bacillus thuringiensis in Doenjang, a Korean Fermented Soybean Paste.

    PubMed

    Park, Kyung Min; Kim, Hyun Jung; Jeong, Moon Cheol; Koo, Minseon

    2016-04-01

    This study determined the prevalence and toxin profile of Bacillus cereus and Bacillus thuringiensis in doenjang, a fermented soybean food, made using both traditional and commercial methods. The 51 doenjang samples tested were broadly contaminated with B. cereus; in contrast, only one sample was positive for B. thuringiensis. All B. cereus isolates from doenjang were positive for diarrheal toxin genes. The frequencies of nheABC and hblACD in traditional samples were 22.7 and 0%, respectively, whereas 5.1 and 5.1% of B. cereus isolates from commercial samples possessed nheABC and hblACD, respectively. The detection rate of ces gene was 10.8%. The predominant toxin profile among isolates from enterotoxigenic B. cereus in doenjang was profile 4 (entFM-bceT-cytK). The major enterotoxin genes in emetic B. cereus were cytK, entFM, and nheA genes. The B. thuringiensis isolate was of the diarrheagenic type. These results provide a better understanding of the epidemiology of the enterotoxigenic and emetic B. cereus groups in Korean fermented soybean products. PMID:27052865

  14. Activity of vegetative insecticidal proteins Vip3Aa58 and Vip3Aa59 of Bacillus thuringiensis against lepidopteran pests.

    PubMed

    Baranek, Jakub; Kaznowski, Adam; Konecka, Edyta; Naimov, Samir

    2015-09-01

    Vegetative insecticidal proteins (Vips) secreted by some isolates of Bacillus thuringiensis show activity against insects and are regarded as insecticides against pests. A number of B. thuringiensis strains harbouring vip3A genes were isolated from different sources and identified by using a PCR based approach. The isolates with the highest insecticidal activity were indicated in screening tests, and their vip genes were cloned and sequenced. The analysis revealed two polymorphic Vip protein forms, which were classified as Vip3Aa58 and Vip3Aa59. After expression of the vip genes, the proteins were isolated and characterized. The activity of both toxins was estimated against economically important lepidopteran pests of woodlands (Dendrolimus pini), orchards (Cydia pomonella) and field crops (Spodoptera exigua). Vip3Aa58 and Vip3Aa59 were highly toxic and their potency surpassed those of many Cry proteins used in commercial bioinsecticides. Vip3Aa59 revealed similar larvicidal activity as Vip3Aa58 against S. exigua and C. pomonella. Despite 98% similarity of amino acid sequences of both proteins, Vip3Aa59 was significantly more active against D. pini. Additionally the effect of proteolytic activation of Vip58Aa and Vip3Aa59 on toxicity of D. pini and S. exigua was studied. Both Vip3Aa proteins did not show any activity against Tenebrio molitor (Coleoptera) larvae. The results suggest that the Vip3Aa58 and Vip3Aa59 toxins might be useful for controlling populations of insect pests of crops and forests. PMID:26146224

  15. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin...

  16. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin...

  17. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin...

  18. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin...

  19. Recombinant Strain of Bacillus thuringiensis Producing Cyt1A, Cry11B, and the Bacillus sphaericus Binary Toxin

    PubMed Central

    Park, Hyun-Woo; Bideshi, Dennis K.; Federici, Brian A.

    2003-01-01

    A novel recombinant Bacillus thuringiensis subsp. israelensis strain that produces the B. sphaericus binary toxin, Cyt1Aa, and Cry11Ba is described. The toxicity of this strain (50% lethal concentration [LC50] = 1.7 ng/ml) against fourth-instar Culex quinquefasciatus was higher than that of B. thuringiensis subsp. israelensis IPS-82 (LC50 = 7.9 ng/ml) or B. sphaericus 2362 (LC50 = 12.6 ng/ml). PMID:12571069

  20. How Quorum Sensing Connects Sporulation to Necrotrophism in Bacillus thuringiensis

    PubMed Central

    Poncet, Sandrine; Lazar, Noureddine; Li de la Sierra-Gallay, Inès; Gohar, Michel; Lereclus, Didier; Nessler, Sylvie

    2016-01-01

    Bacteria use quorum sensing to coordinate adaptation properties, cell fate or commitment to sporulation. The infectious cycle of Bacillus thuringiensis in the insect host is a powerful model to investigate the role of quorum sensing in natural conditions. It is tuned by communication systems regulators belonging to the RNPP family and directly regulated by re-internalized signaling peptides. One such RNPP regulator, NprR, acts in the presence of its cognate signaling peptide NprX as a transcription factor, regulating a set of genes involved in the survival of these bacteria in the insect cadaver. Here, we demonstrate that, in the absence of NprX and independently of its transcriptional activator function, NprR negatively controls sporulation. NprR inhibits expression of Spo0A-regulated genes by preventing the KinA-dependent phosphorylation of the phosphotransferase Spo0F, thus delaying initiation of the sporulation process. This NprR function displays striking similarities with the Rap proteins, which also belong to the RNPP family, but are devoid of DNA-binding domain and indirectly control gene expression via protein-protein interactions in Bacilli. Conservation of the Rap residues directly interacting with Spo0F further suggests a common inhibition of the sporulation phosphorelay. The crystal structure of apo NprR confirms that NprR displays a highly flexible Rap-like structure. We propose a molecular regulatory mechanism in which key residues of the bifunctional regulator NprR are directly and alternatively involved in its two functions. NprX binding switches NprR from a dimeric inhibitor of sporulation to a tetrameric transcriptional activator involved in the necrotrophic lifestyle of B. thuringiensis. NprR thus tightly coordinates sporulation and necrotrophism, ensuring survival and dissemination of the bacteria during host infection. PMID:27483473

  1. How Quorum Sensing Connects Sporulation to Necrotrophism in Bacillus thuringiensis.

    PubMed

    Perchat, Stéphane; Talagas, Antoine; Poncet, Sandrine; Lazar, Noureddine; Li de la Sierra-Gallay, Inès; Gohar, Michel; Lereclus, Didier; Nessler, Sylvie

    2016-08-01

    Bacteria use quorum sensing to coordinate adaptation properties, cell fate or commitment to sporulation. The infectious cycle of Bacillus thuringiensis in the insect host is a powerful model to investigate the role of quorum sensing in natural conditions. It is tuned by communication systems regulators belonging to the RNPP family and directly regulated by re-internalized signaling peptides. One such RNPP regulator, NprR, acts in the presence of its cognate signaling peptide NprX as a transcription factor, regulating a set of genes involved in the survival of these bacteria in the insect cadaver. Here, we demonstrate that, in the absence of NprX and independently of its transcriptional activator function, NprR negatively controls sporulation. NprR inhibits expression of Spo0A-regulated genes by preventing the KinA-dependent phosphorylation of the phosphotransferase Spo0F, thus delaying initiation of the sporulation process. This NprR function displays striking similarities with the Rap proteins, which also belong to the RNPP family, but are devoid of DNA-binding domain and indirectly control gene expression via protein-protein interactions in Bacilli. Conservation of the Rap residues directly interacting with Spo0F further suggests a common inhibition of the sporulation phosphorelay. The crystal structure of apo NprR confirms that NprR displays a highly flexible Rap-like structure. We propose a molecular regulatory mechanism in which key residues of the bifunctional regulator NprR are directly and alternatively involved in its two functions. NprX binding switches NprR from a dimeric inhibitor of sporulation to a tetrameric transcriptional activator involved in the necrotrophic lifestyle of B. thuringiensis. NprR thus tightly coordinates sporulation and necrotrophism, ensuring survival and dissemination of the bacteria during host infection. PMID:27483473

  2. Spider mite infestations reduce Bacillus thuringiensis toxin concentration in corn leaves and predators avoid spider mites that have fed on Bacillus thuringiensis corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic crops containing pyramid-stacked genes for Bacillus thuringiensis derived toxins for controlling coleopteran and lepidopteran pests are increasingly common. As part of environmental risk assessments, these crops are evaluated for toxicity against non-target organisms, and for their poten...

  3. Comparative genomics analysis of the companion mechanisms of Bacillus thuringiensis Bc601 and Bacillus endophyticus Hbe603 in bacterial consortium

    PubMed Central

    Jia, Nan; Ding, Ming-Zhu; Gao, Feng; Yuan, Ying-Jin

    2016-01-01

    Bacillus thuringiensis and Bacillus endophyticus both act as the companion bacteria, which cooperate with Ketogulonigenium vulgare in vitamin C two-step fermentation. Two Bacillus species have different morphologies, swarming motility and 2-keto-L-gulonic acid productivities when they co-culture with K. vulgare. Here, we report the complete genome sequencing of B. thuringiensis Bc601 and eight plasmids of B. endophyticus Hbe603, and carry out the comparative genomics analysis. Consequently, B. thuringiensis Bc601, with greater ability of response to the external environment, has been found more two-component system, sporulation coat and peptidoglycan biosynthesis related proteins than B. endophyticus Hbe603, and B. endophyticus Hbe603, with greater ability of nutrients biosynthesis, has been found more alpha-galactosidase, propanoate, glutathione and inositol phosphate metabolism, and amino acid degradation related proteins than B. thuringiensis Bc601. Different ability of swarming motility, response to the external environment and nutrients biosynthesis may reflect different companion mechanisms of two Bacillus species. Comparative genomic analysis of B. endophyticus and B. thuringiensis enables us to further understand the cooperative mechanism with K. vulgare, and facilitate the optimization of bacterial consortium. PMID:27353048

  4. Comparative genomics analysis of the companion mechanisms of Bacillus thuringiensis Bc601 and Bacillus endophyticus Hbe603 in bacterial consortium.

    PubMed

    Jia, Nan; Ding, Ming-Zhu; Gao, Feng; Yuan, Ying-Jin

    2016-01-01

    Bacillus thuringiensis and Bacillus endophyticus both act as the companion bacteria, which cooperate with Ketogulonigenium vulgare in vitamin C two-step fermentation. Two Bacillus species have different morphologies, swarming motility and 2-keto-L-gulonic acid productivities when they co-culture with K. vulgare. Here, we report the complete genome sequencing of B. thuringiensis Bc601 and eight plasmids of B. endophyticus Hbe603, and carry out the comparative genomics analysis. Consequently, B. thuringiensis Bc601, with greater ability of response to the external environment, has been found more two-component system, sporulation coat and peptidoglycan biosynthesis related proteins than B. endophyticus Hbe603, and B. endophyticus Hbe603, with greater ability of nutrients biosynthesis, has been found more alpha-galactosidase, propanoate, glutathione and inositol phosphate metabolism, and amino acid degradation related proteins than B. thuringiensis Bc601. Different ability of swarming motility, response to the external environment and nutrients biosynthesis may reflect different companion mechanisms of two Bacillus species. Comparative genomic analysis of B. endophyticus and B. thuringiensis enables us to further understand the cooperative mechanism with K. vulgare, and facilitate the optimization of bacterial consortium. PMID:27353048

  5. ssp genes and spore osmotolerance in Bacillus thuringiensis israelensis and Bacillus sphaericus.

    PubMed

    Cucchi, A; Sanchez de Rivas, C

    1995-10-01

    It was shown previously that spores and vegetative cells of Bacillus sphaericus (Bf) and Bacillus thuringiensis israelensis (Bti) are very sensitive to osmotic variations. Since spore osmotolerance has been associated with their SASP (small acid soluble spore proteins) content coded by ssp genes, hybridization assays were performed with sspE and sspA genes from B. subtilis as probes and showed that Bti and Bf strains could lack an sspE-like gene. The B. subtilis sspE gene was then introduced into Bti 4Q2 strain; spores were obtained and showed a 65 to 650 times higher level of osmotolerance to NaCl, without affecting other important properties: hypoosmotic resistance in vegetative cells, spore UV resistance, and larvicidal activity against diptera larvae. PMID:7549769

  6. 40 CFR 174.517 - Bacillus thuringiensis Cry9C protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bacillus thuringiensis Cry9C protein... Cry9C protein in corn; exemption from the requirement of a tolerance. The plant-incorporated protectant Bacillus thuringiensis Cry9C protein in corn is exempted from the requirement of a tolerance for...

  7. 40 CFR 174.517 - Bacillus thuringiensis Cry9C protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Cry9C protein... Cry9C protein in corn; exemption from the requirement of a tolerance. The plant-incorporated protectant Bacillus thuringiensis Cry9C protein in corn is exempted from the requirement of a tolerance for...

  8. 40 CFR 174.517 - Bacillus thuringiensis Cry9C protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Cry9C protein... Cry9C protein in corn; exemption from the requirement of a tolerance. The plant-incorporated protectant Bacillus thuringiensis Cry9C protein in corn is exempted from the requirement of a tolerance for...

  9. 40 CFR 174.517 - Bacillus thuringiensis Cry9C protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacillus thuringiensis Cry9C protein... Cry9C protein in corn; exemption from the requirement of a tolerance. The plant-incorporated protectant Bacillus thuringiensis Cry9C protein in corn is exempted from the requirement of a tolerance for...

  10. 40 CFR 174.517 - Bacillus thuringiensis Cry9C protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Cry9C protein... Cry9C protein in corn; exemption from the requirement of a tolerance. The plant-incorporated protectant Bacillus thuringiensis Cry9C protein in corn is exempted from the requirement of a tolerance for...

  11. 40 CFR 174.504 - Bacillus thuringiensis Cry1F protein in cotton; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Cry1F protein... Cry1F protein in cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1F protein in cotton are exempt from the requirement of a tolerance when used as a...

  12. 40 CFR 174.530 - Bacillus thuringiensis Cry2Ae protein in cotton; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Cry2Ae protein... Cry2Ae protein in cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry2Ae protein in or on the food and feed commodities of cotton; cotton, undelinted seed;...

  13. 40 CFR 174.530 - Bacillus thuringiensis Cry2Ae protein in cotton; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacillus thuringiensis Cry2Ae protein... Cry2Ae protein in cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry2Ae protein in or on the food and feed commodities of cotton; cotton, undelinted seed;...

  14. 40 CFR 174.502 - Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... protein; exemption from the requirement of a tolerance. 174.502 Section 174.502 Protection of Environment...-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.502 Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance. (a) Residues of Bacillus thuringiensis Cry1A.105 protein...

  15. 40 CFR 174.529 - Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... protein as identified under OECD Unique Identifier SYN-IR67B-1 in cotton; exemption from the requirement... Tolerance Exemptions § 174.529 Bacillus thuringiensis modified Cry1Ab protein as identified under OECD... Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN-IR67B-1...

  16. 40 CFR 174.520 - Bacillus thuringiensis Cry1F protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Cry1F protein... Cry1F protein in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1F protein in corn are exempt from the requirement of a tolerance when used as...

  17. 40 CFR 174.530 - Bacillus thuringiensis Cry2Ae protein in cotton; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Cry2Ae protein... Cry2Ae protein in cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry2Ae protein in or on the food and feed commodities of cotton; cotton, undelinted seed;...

  18. 40 CFR 174.502 - Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... protein; exemption from the requirement of a tolerance. 174.502 Section 174.502 Protection of Environment...-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.502 Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance. (a) Residues of Bacillus thuringiensis Cry1A.105 protein...

  19. 40 CFR 174.520 - Bacillus thuringiensis Cry1F protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Cry1F protein... Cry1F protein in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1F protein in corn are exempt from the requirement of a tolerance when used as...

  20. 40 CFR 174.529 - Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... protein as identified under OECD Unique Identifier SYN-IR67B-1 in cotton; exemption from the requirement... Tolerance Exemptions § 174.529 Bacillus thuringiensis modified Cry1Ab protein as identified under OECD... Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN-IR67B-1...

  1. 40 CFR 174.502 - Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... protein; exemption from the requirement of a tolerance. 174.502 Section 174.502 Protection of Environment...-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.502 Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance. (a) Residues of Bacillus thuringiensis Cry1A.105 protein...

  2. 40 CFR 174.504 - Bacillus thuringiensis Cry1F protein in cotton; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Cry1F protein... Cry1F protein in cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1F protein in cotton are exempt from the requirement of a tolerance when used as a...

  3. 40 CFR 174.529 - Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... protein as identified under OECD Unique Identifier SYN-IR67B-1 in cotton; exemption from the requirement... Tolerance Exemptions § 174.529 Bacillus thuringiensis modified Cry1Ab protein as identified under OECD... Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN-IR67B-1...

  4. 40 CFR 174.502 - Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... protein; exemption from the requirement of a tolerance. 174.502 Section 174.502 Protection of Environment...-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.502 Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance. (a) Residues of Bacillus thuringiensis Cry1A.105 protein...

  5. 40 CFR 174.504 - Bacillus thuringiensis Cry1F protein in cotton; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Cry1F protein... Cry1F protein in cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1F protein in cotton are exempt from the requirement of a tolerance when used as a...

  6. 40 CFR 174.520 - Bacillus thuringiensis Cry1F protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Cry1F protein... Cry1F protein in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1F protein in corn are exempt from the requirement of a tolerance when used as...

  7. 40 CFR 174.529 - Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... protein as identified under OECD Unique Identifier SYN-IR67B-1 in cotton; exemption from the requirement... Tolerance Exemptions § 174.529 Bacillus thuringiensis modified Cry1Ab protein as identified under OECD... Bacillus thuringiensis modified Cry1Ab protein as identified under OECD Unique Identifier SYN-IR67B-1...

  8. Expression of Bacillus thuringiensis delta-endotoxin genes during vegetative growth.

    PubMed Central

    Mettus, A M; Macaluso, A

    1990-01-01

    Bacillus thuringiensis delta-endotoxin (crystal protein) genes are normally expressed only during sporulation. It is possible to produce crystal protein during vegetative growth by placing B. thuringiensis crystal protein genes downstream of a strong vegetative promoter. By removing a possible transcriptional terminator of the tetracycline resistance gene of pBC16 and inserting a multiple cloning site, delta-endotoxin genes can be cloned downstream from the tetracycline resistance gene promoter. This construct allows for readthrough transcription from the strong vegetative promoter. Crystal protein is then produced during vegetative growth as well as during sporulation in both B. thuringiensis and Bacillus megaterium. This construct also allows for production of delta-endotoxin in B. thuringiensis strains that do not normally produce delta-endotoxin because of a defect in sporulation. Images PMID:2160219

  9. Extended genetic analysis of Brazilian isolates of Bacillus cereus and Bacillus thuringiensis

    PubMed Central

    Zahner, Viviane; Silva, Ana Carolina Telles de Carvalho e; de Moraes, Gabriela Pinhel; McIntosh, Douglas; de Filippis, Ivano

    2013-01-01

    Multiple locus sequence typing (MLST) was undertaken to extend the genetic characterization of 29 isolates of Bacillus cereus and Bacillus thuringiensis previously characterized in terms of presence/absence of sequences encoding virulence factors and via variable number tandem repeat (VNTR). Additional analysis involved polymerase chain reaction for the presence of sequences (be, cytK, inA, pag, lef, cya and cap), encoding putative virulence factors, not investigated in the earlier study. MLST analysis ascribed novel and unique sequence types to each of the isolates. A phylogenetic tree was constructed from a single sequence of 2,838 bp of concatenated loci sequences. The strains were not monophyletic by analysis of any specific housekeeping gene or virulence characteristic. No clear association in relation to source of isolation or to genotypic profile based on the presence or absence of putative virulence genes could be identified. Comparison of VNTR profiling with MLST data suggested a correlation between these two methods of genetic analysis. In common with the majority of previous studies, MLST was unable to provide clarification of the basis for pathogenicity among members of the B. cereus complex. Nevertheless, our application of MLST served to reinforce the notion that B. cereus and B. thuringiensis should be considered as the same species. PMID:23440117

  10. IS231A from Bacillus thuringiensis is functional in Escherichia coli: transposition and insertion specificity.

    PubMed Central

    Hallet, B; Rezsöhazy, R; Delcour, J

    1991-01-01

    A kanamycin resistance gene was introduced within the insertion sequence IS231A from Bacillus thuringiensis, and transposition of the element was demonstrated in Escherichia coli. DNA sequencing at the target sites showed that IS231A transposition results in direct repeats of variable lengths (10, 11, and 12 bp). These target sequences resemble the terminal inverted repeats of the transposon Tn4430, which are the preferred natural insertion sites of IS231 in B. thuringiensis. Images PMID:1648561

  11. Monarch larvae sensitivity to Bacillus thuringiensis- purified proteins and pollen

    PubMed Central

    Hellmich, Richard L.; Siegfried, Blair D.; Sears, Mark K.; Stanley-Horn, Diane E.; Daniels, Michael J.; Mattila, Heather R.; Spencer, Terrence; Bidne, Keith G.; Lewis, Leslie C.

    2001-01-01

    Laboratory tests were conducted to establish the relative toxicity of Bacillus thuringiensis (Bt) toxins and pollen from Bt corn to monarch larvae. Toxins tested included Cry1Ab, Cry1Ac, Cry9C, and Cry1F. Three methods were used: (i) purified toxins incorporated into artificial diet, (ii) pollen collected from Bt corn hybrids applied directly to milkweed leaf discs, and (iii) Bt pollen contaminated with corn tassel material applied directly to milkweed leaf discs. Bioassays of purified Bt toxins indicate that Cry9C and Cry1F proteins are relatively nontoxic to monarch first instars, whereas first instars are sensitive to Cry1Ab and Cry1Ac proteins. Older instars were 12 to 23 times less susceptible to Cry1Ab toxin compared with first instars. Pollen bioassays suggest that pollen contaminants, an artifact of pollen processing, can dramatically influence larval survival and weight gains and produce spurious results. The only transgenic corn pollen that consistently affected monarch larvae was from Cry1Ab event 176 hybrids, currently <2% corn planted and for which re-registration has not been applied. Results from the other types of Bt corn suggest that pollen from the Cry1Ab (events Bt11 and Mon810) and Cry1F, and experimental Cry9C hybrids, will have no acute effects on monarch butterfly larvae in field settings. PMID:11559841

  12. Evolution of Bacillus thuringiensis Cry toxins insecticidal activity

    PubMed Central

    Bravo, Alejandra; Gómez, Isabel; Porta, Helena; García-Gómez, Blanca Ines; Rodriguez-Almazan, Claudia; Pardo, Liliana; Soberón, Mario

    2013-01-01

    Insecticidal Cry proteins produced by Bacillus thuringiensis are use worldwide in transgenic crops for efficient pest control. Among the family of Cry toxins, the three domain Cry family is the better characterized regarding their natural evolution leading to a large number of Cry proteins with similar structure, mode of action but different insect specificity. Also, this group is the better characterized regarding the study of their mode of action and the molecular basis of insect specificity. In this review we discuss how Cry toxins have evolved insect specificity in nature and analyse several cases of improvement of Cry toxin action by genetic engineering, some of these examples are currently used in transgenic crops. We believe that the success in the improvement of insecticidal activity by genetic evolution of Cry toxins will depend on the knowledge of the rate-limiting steps of Cry toxicity in different insect pests, the mapping of the specificity binding regions in the Cry toxins, as well as the improvement of mutagenesis strategies and selection procedures. PMID:22463726

  13. Continuous evolution of Bacillus thuringiensis toxins overcomes insect resistance.

    PubMed

    Badran, Ahmed H; Guzov, Victor M; Huai, Qing; Kemp, Melissa M; Vishwanath, Prashanth; Kain, Wendy; Nance, Autumn M; Evdokimov, Artem; Moshiri, Farhad; Turner, Keith H; Wang, Ping; Malvar, Thomas; Liu, David R

    2016-05-01

    The Bacillus thuringiensis δ-endotoxins (Bt toxins) are widely used insecticidal proteins in engineered crops that provide agricultural, economic, and environmental benefits. The development of insect resistance to Bt toxins endangers their long-term effectiveness. Here we have developed a phage-assisted continuous evolution selection that rapidly evolves high-affinity protein-protein interactions, and applied this system to evolve variants of the Bt toxin Cry1Ac that bind a cadherin-like receptor from the insect pest Trichoplusia ni (TnCAD) that is not natively bound by wild-type Cry1Ac. The resulting evolved Cry1Ac variants bind TnCAD with high affinity (dissociation constant Kd = 11-41 nM), kill TnCAD-expressing insect cells that are not susceptible to wild-type Cry1Ac, and kill Cry1Ac-resistant T. ni insects up to 335-fold more potently than wild-type Cry1Ac. Our findings establish that the evolution of Bt toxins with novel insect cell receptor affinity can overcome insect Bt toxin resistance and confer lethality approaching that of the wild-type Bt toxin against non-resistant insects. PMID:27120167

  14. Development of sludge based stable aqueous Bacillus thuringiensis formulations.

    PubMed

    Brar, S K; Verma, M; Tyagi, R D; Valéro, J R; Surampalli, R Y; Banerji, S K

    2004-01-01

    This study focuses on development of aqueous flowable (suspension) formulations for Bacillus thuringiensis (Bt) based biopesticides from wastewater sludge. Different inerts like sorbitol, sodium monophosphate, sodium metabisulphite, sorbic acid, propionic acid, Tween-80, Triton X-100 and glycerol were tested for formulations. Five different formulations for non-hydrolyzed (NH) secondary sludges were tried and the best combination selected on the basis of various physical parameters like viscosity, particle size, suspendibility, entomotoxicity, and microbiological purity tests. F5 formulations (for secondary sludge) comprising sorbitol, sodium monophosphate and sodium metabisulphite gave better physical and biological characteristics with a small effect on entomotoxicity and spore concentration after 120 days at pH 6, 6.5 and temperatures 40 and 50 degrees C and viscosity change at 40 and 50 degrees C. The formulations were more stable at pH 4.0 to 5.0 and temperatures 4 to 30 degrees C whereas at pH 6.0 and 6.5 and temperatures 40 and 50 degrees C, there was degeneration of the product. Lower proteolytic activity and physical factors like ionic strength and surface group changes at pH 6 and 6.5 were responsible for the instability of the formulation. PMID:15581017

  15. Starch industry wastewater-based stable Bacillus thuringiensis liquid formulations.

    PubMed

    Brar, Satinder K; Verma, M; Tyagi, R D; Valéro, J R; Surampalli, R Y

    2005-12-01

    Liquid formulations were developed from Bacillus thuringiensis (Bt)-fermented broths of starch industry wastewater (SIW) and of soya medium. Stability studies were carried out for 1 yr. Storage stability was tested by studying various physical and chemical (e.g., viscosity, particle size, corrosion, and suspendibility) and biological (e.g., microbial contamination, viable spores, and entomotoxicity) parameters at different pH levels and temperatures. Three suspending agents, sorbitol, sodium monophosphate, and sodium metabisulfite, were added to fermented broth in different concentrations. Sorbitol and sodium monophosphate in the ratio 3:1 was the best suspending agent combination for both formulations. Starch industry wastewater fermentation yielded cell and viable spore counts 10- and 4-fold greater than those from soya medium, respectively, and a 1.7-fold increase in entomotoxicity. However, both formulations started deteriorating at pH 6 and 6.5 and 40 and 50 degrees C. There were no signs of corrosion and microbial contamination in both types of formulations. PMID:16539110

  16. Adhesion of Spores of Bacillus thuringiensis on a Planar Surface

    SciTech Connect

    Chung, Eunhyea; Kweon, Hyojin; Yiacoumi, Sotira; Lee, Ida; Joy, David Charles; Palumbo, Anthony Vito; Tsouris, Costas

    2010-01-01

    Adhesion of spores of Bacillus thuringiensis (Bt) and spherical silica particles on surfaces was experimentally and theoretically investigated in this study. Topography analysis via atomic force microscopy (AFM) and electron microscopy indicates that Bt spores are rod shaped, {approx}1.3 {mu}m in length and {approx}0.8 {mu}m in diameter. The adhesion force of Bt spores and silica particles on gold-coated glass was measured at various relative humidity (RH) levels by AFM. It was expected that the adhesion force would vary with RH because the individual force components contributing to the adhesion force depend on RH. The adhesion force between a particle and a planar surface in atmospheric environments was modeled as the contribution of three major force components: capillary, van der Waals, and electrostatic interaction forces. Adhesion force measurements for Bt spore (silica particle) and the gold surface system were comparable with calculations. Modeling results show that there is a critical RH value, which depends on the hydrophobicity of the materials involved, below which the water meniscus does not form and the contribution of the capillary force is zero. As RH increases, the van der Waals force decreases while the capillary force increases to a maximum value.

  17. The impact of secondary pests on Bacillus thuringiensis (Bt) crops.

    PubMed

    Catarino, Rui; Ceddia, Graziano; Areal, Francisco J; Park, Julian

    2015-06-01

    The intensification of agriculture and the development of synthetic insecticides enabled worldwide grain production to more than double in the last third of the 20th century. However, the heavy dependence and, in some cases, overuse of insecticides has been responsible for negative environmental and ecological impacts across the globe, such as a reduction in biodiversity, insect resistance to insecticides, negative effects on nontarget species (e.g. natural enemies) and the development of secondary pests. The use of recombinant DNA technology to develop genetically engineered insect-resistant crops could mitigate many of the negative side effects of insecticides. One such genetic alteration enables crops to express toxic crystalline (Cry) proteins from the soil bacteria Bacillus thuringiensis (Bt). Despite the widespread adoption of Bt crops, there are still a range of unanswered questions concerning longer term agro-ecosystem interactions. For instance, insect species that are not susceptible to the expressed toxin can develop into secondary pests and cause significant damage to the crop. Here, we review the main causes surrounding secondary pest dynamics in Bt crops and the impact of such outbreaks. Regardless of the causes, if nonsusceptible secondary pest populations exceed economic thresholds, insecticide spraying could become the immediate solution at farmers' disposal, and the sustainable use of this genetic modification technology may be in jeopardy. Based on the literature, recommendations for future research are outlined that will help to improve the knowledge of the possible long-term ecological trophic interactions of employing this technology. PMID:25832330

  18. Raman spectroscopy of Bacillus thuringiensis physiology and inactivation

    NASA Astrophysics Data System (ADS)

    Morrow, J. B.; Almeida, J.; Cole, K. D.; Reipa, V.

    2012-12-01

    The ability to detect spore contamination and inactivation is relevant to developing and determining decontamination strategy success for food and water safety. This study was conducted to develop a systematic comparison of nondestructive vibrational spectroscopy techniques (Surface-Enhanced Raman Spectroscopy, SERS, and normal Raman) to determine indicators of Bacillus thuringiensis physiology (spore, vegetative, outgrown, germinated and inactivated spore forms). SERS was found to provide better resolution of commonly utilized signatures of spore physiology (dipicolinic acid at 1006 cm-1 and 1387 cm-1) compared to normal Raman and native fluorescence indigenous to vegetative and outgrown cell samples was quenched in SERS experiment. New features including carotenoid pigments (Raman features at 1142 cm-1, 1512 cm-1) were identified for spore cell forms. Pronounced changes in the low frequency region (300 cm-1 to 500 cm-1) in spore spectra occurred upon germination and inactivation (with both free chlorine and by autoclaving) which is relevant to guiding decontamination and detection strategies using Raman techniques.

  19. Role of receptors in Bacillus thuringiensis crystal toxin activity.

    PubMed

    Pigott, Craig R; Ellar, David J

    2007-06-01

    Bacillus thuringiensis produces crystalline protein inclusions with insecticidal or nematocidal properties. These crystal (Cry) proteins determine a particular strain's toxicity profile. Transgenic crops expressing one or more recombinant Cry toxins have become agriculturally important. Individual Cry toxins are usually toxic to only a few species within an order, and receptors on midgut epithelial cells have been shown to be critical determinants of Cry specificity. The best characterized of these receptors have been identified for lepidopterans, and two major receptor classes have emerged: the aminopeptidase N (APN) receptors and the cadherin-like receptors. Currently, 38 different APNs have been reported for 12 different lepidopterans. Each APN belongs to one of five groups that have unique structural features and Cry-binding properties. While 17 different APNs have been reported to bind to Cry toxins, only 2 have been shown to mediate toxin susceptibly in vivo. In contrast, several cadherin-like proteins bind to Cry toxins and confer toxin susceptibility in vitro, and disruption of the cadherin gene has been associated with toxin resistance. Nonetheless, only a small subset of the lepidopteran-specific Cry toxins has been shown to interact with cadherin-like proteins. This review analyzes the interactions between Cry toxins and their receptors, focusing on the identification and validation of receptors, the molecular basis for receptor recognition, the role of the receptor in resistant insects, and proposed models to explain the sequence of events at the cell surface by which receptor binding leads to cell death. PMID:17554045

  20. Investigation of lead(II) uptake by Bacillus thuringiensis 016.

    PubMed

    Chen, Zhi; Pan, Xiaohong; Chen, Hui; Lin, Zhang; Guan, Xiong

    2015-11-01

    In this work, we investigated the lead(II) biosorption mechanism of Bacillus thuringiensis (Bt) 016 through batch and microscopic experiments. We found that the maximum lead(II) biosorption capacity of Bt 016 was 164.77 mg/g (dry weight). The pH value could affect the biosorption of lead(II) in a large extent. Fourier transform infrared analyses and selective passivation experiments suggested that the carboxyl, amide and phosphate functional groups of Bt 016 played an important role in lead(II) biosorption. Scanning electron microscopy observation showed that noticeable lead(II) precipitates were accumulated on bacterial surfaces. Further transmission electron microscopy thin section analysis coupled with energy dispersive X-ray spectroscopy as well as selected area electron diffraction indicated that lead(II) immobilized on the bacteria could be transformated into random-shaped crystalline lead-containing minerals eventually. This work provided a new insight into lead(II) uptake of Bt, highlighting the potential of Bt in the restoration of lead(II) contaminated repositories. PMID:26271773

  1. Complete genome sequence of Bacillus thuringiensis subsp. chinensis strain CT-43.

    PubMed

    He, Jin; Wang, Jieping; Yin, Wen; Shao, Xiaohu; Zheng, Huajun; Li, Mingshun; Zhao, Youwen; Sun, Ming; Wang, Shengyue; Yu, Ziniu

    2011-07-01

    Bacillus thuringiensis has been widely used as an agricultural biopesticide for a long time. As a producing strain, B. thuringiensis subsp. chinensis strain CT-43 is highly toxic to lepidopterous and dipterous insects. It can form various parasporal crystals consisting of Cry1Aa3, Cry1Ba1, Cry1Ia14, Cry2Aa9, and Cry2Ab1. During fermentation, it simultaneously generates vegetative insecticidal protein Vip3Aa10 and the insecticidal nucleotide analogue thuringiensin. Here, we report the finished, annotated genome sequence of B. thuringiensis strain CT-43. PMID:21551307

  2. A Bacillus thuringiensis S-Layer Protein Involved in Toxicity against Epilachna varivestis (Coleoptera: Coccinellidae)

    PubMed Central

    Peña, Guadalupe; Miranda-Rios, Juan; de la Riva, Gustavo; Pardo-López, Liliana; Soberón, Mario; Bravo, Alejandra

    2006-01-01

    The use of Bacillus thuringiensis as a biopesticide is a viable alternative for insect control since the insecticidal Cry proteins produced by these bacteria are highly specific; harmless to humans, vertebrates, and plants; and completely biodegradable. In addition to Cry proteins, B. thuringiensis produces a number of extracellular compounds, including S-layer proteins (SLP), that contribute to virulence. The S layer is an ordered structure representing a proteinaceous paracrystalline array which completely covers the surfaces of many pathogenic bacteria. In this work, we report the identification of an S-layer protein by the screening of B. thuringiensis strains for activity against the coleopteran pest Epilachna varivestis (Mexican bean beetle; Coleoptera: Coccinellidae). We screened two B. thuringiensis strain collections containing unidentified Cry proteins and also strains isolated from dead insects. Some of the B. thuringiensis strains assayed against E. varivestis showed moderate toxicity. However, a B. thuringiensis strain (GP1) that was isolated from a dead insect showed a remarkably high insecticidal activity. The parasporal crystal produced by the GP1 strain was purified and shown to have insecticidal activity against E. varivestis but not against the lepidopteran Manduca sexta or Spodoptera frugiperda or against the dipteran Aedes aegypti. The gene encoding this protein was cloned and sequenced. It corresponded to an S-layer protein highly similar to previously described SLP in Bacillus anthracis (EA1) and Bacillus licheniformis (OlpA). The phylogenetic relationships among SLP from different bacteria showed that these proteins from Bacillus cereus, Bacillus sphaericus, B. anthracis, B. licheniformis, and B. thuringiensis are arranged in the same main group, suggesting similar origins. This is the first report that demonstrates that an S-layer protein is directly involved in toxicity to a coleopteran pest. PMID:16391064

  3. Interaction between the predator Podisus nigrispinus (Hemiptera: Pentatomidae) and the entomopathogenic bacteria Bacillus thuringiensis.

    PubMed

    Carvalho, V F P; Vacari, A M; Pomari, A F; De Bortoli, C P; Ramalho, D G; De Bortoli, S A

    2012-12-01

    Plutella xylostella (L.) is susceptible to both the entomopathogen Bacillus thuringiensis and the predator, Brazilian spined soldier bug [Podisus nigrispinus (Dallas)]. The objective of this study was to measure the interaction between the bacterium B. thuringiensis and the predator P. nigrispinus. We also studied the behavior of P. nigrispinus in relation to its choice between B. thuringiensis-infected and healthy P. xylostellais larvae. In the first treatment, P. nigrispinus nymphs were fed daily with B. thuringiensis-infected P. xylostella larvae and distilled water. In the second treatment, nymphs were fed daily with healthy larvae and a suspension of B. thuringiensis as a source of water. The control nymphs were fed daily with healthy larvae and water. Adult P. nigrispinus were separated by sex, couples were formed, and they were fed daily with P. xylostella larvae derived from the treatments. We followed the development of P. nigrispinus and measured its biological characteristics. On the basis of these data, parameters were determined for the construction of life tables. A choice test was used to compare infected and healthy larvae. The HD1 strain of B. thuringiensis does not affect the biological characteristics of P. nigrispinus when fed infected larvae and water or healthy larvae and B. thuringiensis suspension. Our study shows that integrated management of P. xylostella, a pest of the Brassicaceae, is feasible by using the HD1 strain of B. thuringiensis and the predator P. nigrispinus, because the predator shows no preference for infected or healthy P. xylostella larvae. PMID:23321092

  4. Spatio-Temporal Evolution of Sporulation in Bacillus thuringiensis Biofilm.

    PubMed

    El-Khoury, Nay; Majed, Racha; Perchat, Stéphane; Kallassy, Mireille; Lereclus, Didier; Gohar, Michel

    2016-01-01

    Bacillus thuringiensis can produce a floating biofilm which includes two parts: a ring and a pellicle. The ring is a thick structure which sticks to the culture container, while the pellicle extends over the whole liquid surface and joins the ring. We have followed over time, from 16 to 96 h, sporulation in the two biofilm parts. Sporulation was followed in situ in 48-wells polystyrene microtiterplates with a fluorescence binocular stereomicroscope and a spoIID-yfp transcriptional fusion. Sporulation took place much earlier in the ring than in the pellicle. In 20 h-aged biofilms, spoIID was expressed only in the ring, which could be seen as a green fluorescent circle surrounding the non-fluorescent pellicle. However, after 48 h of culture, the pellicle started to express spoIID in specific area corresponding to protrusions, and after 96 h both the ring and the whole pellicle expressed spoIID. Spore counts and microscopy observations of the ring and the pellicle harvested separately confirmed these results and revealed that sporulation occured 24 h-later in the pellicle comparatively to the ring, although both structures contained nearly 100% spores after 96 h of culture. We hypothesize that two mechanisms, due to microenvironments in the biofilm, can explain this difference. First, the ring experiences a decreased concentration of nutrients earlier than the pellicle, because of a lower exchange area with the culture medium. An second, the ring is exposed to partial dryness. Both reasons could speed up sporulation in this biofilm structure. Our results also suggest that spores in the biofilm display a phenotypic heterogeneity. These observations might be of particular significance for the food industry, since the biofilm part sticking to container walls - the ring - is likely to contain spores and will therefore resist both to washing and to cleaning procedures, and will be able to restart a new biofilm when food production has resumed. PMID:27536298

  5. Field evaluation of Bacillus thuringiensis H-14 against Aedes mosquitoes.

    PubMed

    Lee, Y W; Zairi, J

    2006-06-01

    Studies were carried out on the residual efficacy of Bacillus thuringiensis H-14 (water dispersible granule, VectoBac ABG 6511) as direct application in the control of Aedes larvae in the field. Field Aedes sp populations in the earthen and glass jars were predetermined before initiation of the trial. On confirmation of the presence of Aedes species in the designated area, Sungai Nibong Kecil, Penang Island, Malaysia, Bti was introduced in the 55L earthen and 3L glass jars). Two test designs were carried out. The first design had treated water replenished daily with 6L of seasoned water and the second design is without the replenishment of water but evaporated water was replenished. Bti was effective in the field for at least 35 days with more than 80% reduction in the Aedes larvae in the treated containers. For earthen jars with daily replenishment of water, 100% reduction was recorded for the first 3 days, while more than 80% reduction was recorded up to day 40. At day 60, Bti still provided an efficacy of 54.32 +/- 4.61 (%) of reduction. Whilst for earthen jars without daily replenishment of water, 100% reduction was recorded for the first 5 days, while more than 80% of reduction was recorded up to day 40. For the glass jars studied, similar efficacy was observed. In jars with daily replenishment of water a better larval control was observed. Percentage of reduction from day 50 to 60 for replenishment of water was between 50 to 70% compared to without replenishment of water with less than 40%. PMID:17041550

  6. Spatio-Temporal Evolution of Sporulation in Bacillus thuringiensis Biofilm

    PubMed Central

    El-Khoury, Nay; Majed, Racha; Perchat, Stéphane; Kallassy, Mireille; Lereclus, Didier; Gohar, Michel

    2016-01-01

    Bacillus thuringiensis can produce a floating biofilm which includes two parts: a ring and a pellicle. The ring is a thick structure which sticks to the culture container, while the pellicle extends over the whole liquid surface and joins the ring. We have followed over time, from 16 to 96 h, sporulation in the two biofilm parts. Sporulation was followed in situ in 48-wells polystyrene microtiterplates with a fluorescence binocular stereomicroscope and a spoIID-yfp transcriptional fusion. Sporulation took place much earlier in the ring than in the pellicle. In 20 h-aged biofilms, spoIID was expressed only in the ring, which could be seen as a green fluorescent circle surrounding the non-fluorescent pellicle. However, after 48 h of culture, the pellicle started to express spoIID in specific area corresponding to protrusions, and after 96 h both the ring and the whole pellicle expressed spoIID. Spore counts and microscopy observations of the ring and the pellicle harvested separately confirmed these results and revealed that sporulation occured 24 h-later in the pellicle comparatively to the ring, although both structures contained nearly 100% spores after 96 h of culture. We hypothesize that two mechanisms, due to microenvironments in the biofilm, can explain this difference. First, the ring experiences a decreased concentration of nutrients earlier than the pellicle, because of a lower exchange area with the culture medium. An second, the ring is exposed to partial dryness. Both reasons could speed up sporulation in this biofilm structure. Our results also suggest that spores in the biofilm display a phenotypic heterogeneity. These observations might be of particular significance for the food industry, since the biofilm part sticking to container walls – the ring – is likely to contain spores and will therefore resist both to washing and to cleaning procedures, and will be able to restart a new biofilm when food production has resumed. PMID:27536298

  7. Cloning, characterization and expression of a novel haplotype cry2A-type gene from Bacillus thuringiensis strain SWK1, native to Himalayan valley Kashmir.

    PubMed

    Reyaz, A L; Arulselvi, P Indra

    2016-05-01

    Bacillus thuringiensis (Bt) is a gram positive bacterium which is effectively being used in pest management strategies as an eco-friendly bioinsecticide. In the present study a new cry2A gene was cloned from a promising indigenous B. thuringiensis SWK1 strain previously characterized for its toxicity against Spodoptera litura and Helicoverpa armigera larvae. The nucleotide sequence of the cloned cry2A gene pointed out that the open reading frame has 1902 bases encoding a polypeptide of 634 amino acid residues with a probable molecular weight of 70kDa. Homology comparisons showed that the deduced amino acid sequence of Cry2A had a similarity of 94% compared to that of the known Cry2Aa protein in the NCBI database and this gene has been named as cry2Al1 by the B. thuringiensis δ-endotoxin Nomenclature Committee. cry2Al1 was ligated into pET 22b vector and expressed in Escherichia coli BL21 (DE3) pLysS under the control of T7 promoter induced by isopropyl-beta-d-thiogalactopyranoside (IPTG). SDS-PAGE analysis confirmed the expression of cry2Al1 as ∼65kDa protein. Insect pest bioassays with neonate larvae of S. litura and H. armigera showed that the purified Cry2Al1 are toxic to S. litura and H. armigera with LC50 2.448μg/ml and H. armigera with 3.374μg/ml respectively. PMID:26906447

  8. Transfer of Bacillus thuringiensis plasmids coding for delta-endotoxin among strains of B. thuringiensis and B. cereus.

    PubMed Central

    González, J M; Brown, B J; Carlton, B C

    1982-01-01

    The recently discovered high-frequency transfer of plasmids between strains of Bacillus thuringiensis was used to study the genetic relationship between plasmids and production of the insecticidal delta-endotoxin crystal. Three strains of B. thuringiensis transmitted the Cry+ (crystal-producing) phenotype to Cry- (acrystalliferous) B. thuringiensis recipients. Agarose gel electrophoresis showed that one specific plasmid from each donor strain was always present in Cry+ "transcipients." The size of the transmissible crystal-coding plasmid varied with the donor strain, being 75 MDal (megadaltons) in size in HD-2, 50 MDal in HD-73, and 44 MDal in HD-263. Immunological analysis showed the Cry+ transcipients to be hybrid strains, having flagella of the recipient serotype and crystals of the donor serotype. These results demonstrate that the structural genes for the delta-endotoxin are plasmid borne. Crystal-coding plasmids also transferred into two strains of the related species Bacillus cereus and yielded transcipients that produced crystals of the same antigenicity as the donor strain. Images PMID:6294667

  9. Urea-Mercaptoethanol-Soluble Protein from Spores of Bacillus thuringiensis and Other Species

    PubMed Central

    Somerville, H. J.; Delafield, F. P.; Rittenberg, S. C.

    1970-01-01

    Treatment with urea-mercaptoethanol of purified spores of Bacillus thuringiensis, other Bacillus species, and Clostridium roseum solubilizes a protein fraction between 5 and 12% of the dry weight of the spores. This fraction behaves identically to the crystal protein of B. thuringiensis on acrylamide-gel electrophoresis. The protein from all of the Bacillus species shows partial homology with crystal protein, using the Ouchterlony immunodiffusion technique. A further fraction, similar in amount, can be removed from spores of B. thuringiensis by the addition of sodium lauryl sulfate to the urea-mercaptoethanol. Spores of B. thuringiensis extracted in these ways show no difference when compared to untreated spores with respect to viability or resistance to heat and ultraviolet-irradiation. The extracted spores do show differences in their germination requirements and their susceptibility to phase-darkening by lysozyme. It is concluded that an urea-mercaptoethanol-soluble protein or class of protein is a widespread component of bacterial spores, possibly located in the spore coat, and that this protein may be related to the crystal protein of B. thuringiensis. Images PMID:4984077

  10. 40 CFR 174.519 - Bacillus thuringiensis Cry2Ab2 protein in corn and cotton; exemption from the requirement of a...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacillus thuringiensis Cry2Ab2 protein... thuringiensis Cry2Ab2 protein in corn and cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry2Ab2 protein in or on corn or cotton are exempt from the requirement of...

  11. 40 CFR 174.519 - Bacillus thuringiensis Cry2Ab2 protein in corn and cotton; exemption from the requirement of a...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Cry2Ab2 protein... thuringiensis Cry2Ab2 protein in corn and cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry2Ab2 protein in or on corn or cotton are exempt from the requirement of...

  12. 40 CFR 174.519 - Bacillus thuringiensis Cry2Ab2 protein in corn and cotton; exemption from the requirement of a...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Cry2Ab2 protein... thuringiensis Cry2Ab2 protein in corn and cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry2Ab2 protein in or on corn or cotton are exempt from the requirement of...

  13. 40 CFR 174.519 - Bacillus thuringiensis Cry2Ab2 protein in corn and cotton; exemption from the requirement of a...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Cry2Ab2 protein... thuringiensis Cry2Ab2 protein in corn and cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry2Ab2 protein in or on corn or cotton are exempt from the requirement of...

  14. 40 CFR 174.501 - Bacillus thuringiensis Vip3Aa protein in corn and cotton; exemption from the requirement of a...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Vip3Aa protein... thuringiensis Vip3Aa protein in corn and cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Vip3Aa proteins in or on corn or cotton are exempt from the requirement of...

  15. 40 CFR 174.501 - Bacillus thuringiensis Vip3Aa protein in corn and cotton; exemption from the requirement of a...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacillus thuringiensis Vip3Aa protein... thuringiensis Vip3Aa protein in corn and cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Vip3Aa proteins in or on corn or cotton are exempt from the requirement of...

  16. 40 CFR 174.501 - Bacillus thuringiensis Vip3Aa protein in corn and cotton; exemption from the requirement of a...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Vip3Aa protein... thuringiensis Vip3Aa protein in corn and cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Vip3Aa proteins in or on corn or cotton are exempt from the requirement of...

  17. 40 CFR 174.501 - Bacillus thuringiensis Vip3Aa protein in corn and cotton; exemption from the requirement of a...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Vip3Aa protein... thuringiensis Vip3Aa protein in corn and cotton; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Vip3Aa proteins in or on corn or cotton are exempt from the requirement of...

  18. Translocation and insecticidal activity of Bacillus thuringiensis living inside of plants

    PubMed Central

    Monnerat, Rose Gomes; Soares, Carlos Marcelo; Capdeville, Guy; Jones, Gareth; Martins, Érica Soares; Praça, Lilian; Cordeiro, Bruno Arrivabene; Braz, Shélida Vasconcelos; Dos Santos, Roseane Cavalcante; Berry, Colin

    2009-01-01

    Summary The major biological pesticide for the control of insect infestations of crops, Bacillus thuringiensis was found to be present naturally within cotton plants from fields that had never been treated with commercial formulations of this bacterium. The ability of B. thuringiensis to colonize plants as an endophyte was further established by the introduction of a strain marked by production of green fluorescent protein (GFP). After inoculation of this preparation close to the roots of cotton and cabbage seedlings, GFP‐marked bacteria could be re‐isolated from all parts of the plant, having entered the roots and migrated through the xylem. Leaves taken from the treated plants were able to cause toxicity when fed to the Lepidoptera Spodoptera frugiperda (cotton) and Plutella xylostella (cabbage). These results open up new horizons for understanding the natural ecology and evolution of B. thuringiensis and use of B. thuringiensis in insect control. PMID:21255282

  19. A preliminary study of the bioactivity of vegetative proteins extracted from Malaysian Bacillus thuringiensis isolates.

    PubMed

    Ramasamy, B; Nadarajah, V D; Soong, Z K; Lee, H L; Mohammad, S M

    2008-04-01

    Vegetative proteins from Malaysian strains of Bacillus thuringiensis israelensis strains (Bt 11, Bt 12, Bt 15, Bt 16, Bt 17, Bt 21 and Bt 22) and Bacillus sphaericus H-25 strains (Bs 1 and Bs 2) were screened for haemolytic, cytotoxic and larvicidal activity. SDS-PAGE profiles of the Bacillus thuringiensis strains studied consistently showed major bands of 33-37 kDa and 47 kDa. Bt 16 also showed two bands of 66 kDa and 45 kDa similar to the previously reported binary vegetative protein, Vip1Ac (66 kDa) and Vip 2Ac (45 kDa). Both the Bacillus sphaericus strains showed a 35 kDa band that was similiar to a previously reported vegetative protein, the Mtx2 protein. Bs 2 also contains a 37 kDa band, similar to another vegetative protein, the Mtx 3 protein. With the exception of Bt 17 and Bt 21, vegetative proteins from all Bacillus thuringiensis and Bacillus sphaericus strains were highly haemolytic to human erythrocytes, causing more than 75% haemolysis at the highest concentration of 200 microg/ml. High haemolytic activity was associated with high cytotoxic activity with most of the haemolytic strains being indiscriminately cytotoxic to both CEM-SS (human T lymphoblastoid) and HeLa (human uterus cervical cancer) cell lines. Interestingly, the less haemolytic vegetative proteins from Bt 17 and Bt 21 demonstrated cytotoxic activity comparable to that of the highly haemolytic vegetative proteins. Bt 21 displayed toxicity towards both cell lines while Bt 17 was more toxic towards CEM-SS cells. Bioassay against Aedes aegypti and Culex quinquefasciatus larvae revealed that vegetative proteins from the Bacillus thuringiensis strains had activity against both species of larvae but vegetative proteins from Bacillus sphaericus were weakly larvicidal towards Cx. quinquefasciatus only. PMID:18600206

  20. Analysis of opportunities and challenges in patenting of Bacillus thuringiensis insecticidal crystal protein genes.

    PubMed

    Swamy, H M Mahadeva; Asokan, R; Rajasekaran, P E; Mahmood, Riaz; Nagesha, S N; Arora, D K

    2012-04-01

    Bacillus thuringiensis (Bt) is the most widely used microbial control agent. The broad spectrum of susceptible hosts, production on artificial media and ease of application has caused the widespread use of this bacterium against several pests in agriculture, forest and vectors of human diseases. B.thuringiensis toxins are highly species specific which provide economic, environmental benefits, potential for future control and spread of the technology worldwide. This makes the B. thuringiensis crystal proteins an interesting tool for the implementation in integrated pest management programs. It has gained importance over the last 100 years for its biocontrol properties which is used in this review as a case study and analysis of the patents granted on B. thuringiensis was carried out. This study categorizes a number of patents related to B.thuringiensis insecticidal crystal proteins, application of B.thuringiensis insecticidal crystal proteins and the development of patentable technologies. The analyses were done using various criteria like patenting trends over the years, assignees playing a major role, comparison of the technology used in different patents and the patenting activity across the insect orders. Patent documents related to bacterium B.thuringiensis contain a trove of technical and commercial information and thus, patent analysis is considered as a useful tool for R management and techno economical development. Patent analysis also helps identifying and evaluating new and alternate technologies, keeping abreast with latest technologies for business interests, finding solutions to technical problems and ideas for new innovative trends. PMID:22239684

  1. Requirement of Simultaneous Assessment of Crystal- and Supernatant-Related Entomotoxic Activities of Bacillus thuringiensis Strains for Biocontrol-Product Development

    PubMed Central

    Argôlo-Filho, Ronaldo Costa; Costa, Robson Luz; Pinheiro, Daniele Heloisa; Corrêa, Fábio Mathias; Valicente, Fernando Hercos; Pomella, Alan William Vilela; Loguercio, Leandro Lopes

    2014-01-01

    Bioinsecticides with lower concentrations of endospores/crystals and without loss of efficiency are economically advantageous for pest biocontrol. In addition to Cry proteins, other Bacillus thuringiensis (Bt) toxins in culture supernatants (SN) have biocontrol potential (e.g., Vip3A, Cry1I, Sip1), whereas others are unwanted (β-exotoxins), as they display widespread toxicity across taxa. A strain simultaneously providing distinct toxin activities in crystals and SN would be desirable for bioinsecticides development; however, strains secreting β-exotoxins should be discarded, independently of other useful entomotoxins. Entomotoxicity of crystals and SN from a Brazilian Bt tolworthi strain (Btt01) was tested against Spodoptera frugiperda to assess the potential for biocontrol-product development based on more than one type of toxin/activity. Tests showed that 107 endospores mL−1 caused >80% of larvae mortality, suggesting Btt01 may be used in similar concentrations as those of other Bt-based biopesticides. When it was applied to cornfields, a significant 60% reduction of larvae infestation was observed. However, bioassays with Btt01 SN revealed a thermostable toxic activity. Physicochemical characterization strongly suggests the presence of unwanted β-exotoxins, with isolate-specific temporal variation in its secretion. Knowledge of the temporal pattern of secretion/activity in culture for all forms of toxins produced by a single strain is required to both detect useful activities and avoid the potential lack of identification of undesirable toxins. These findings are discussed in the contexts of commercial Bt product development, advantages of multiple-activity strains, and care and handling recommended for large-scale fermentation systems. PMID:24854738

  2. Requirement of simultaneous assessment of crystal- and supernatant-related entomotoxic activities of Bacillus thuringiensis strains for biocontrol-product development.

    PubMed

    Argôlo-Filho, Ronaldo Costa; Costa, Robson Luz; Pinheiro, Daniele Heloisa; Corrêa, Fábio Mathias; Valicente, Fernando Hercos; Pomella, Alan William Vilela; Loguercio, Leandro Lopes

    2014-05-01

    Bioinsecticides with lower concentrations of endospores/crystals and without loss of efficiency are economically advantageous for pest biocontrol. In addition to Cry proteins, other Bacillus thuringiensis (Bt) toxins in culture supernatants (SN) have biocontrol potential (e.g., Vip3A, Cry1I, Sip1), whereas others are unwanted (β-exotoxins), as they display widespread toxicity across taxa. A strain simultaneously providing distinct toxin activities in crystals and SN would be desirable for bioinsecticides development; however, strains secreting β-exotoxins should be discarded, independently of other useful entomotoxins. Entomotoxicity of crystals and SN from a Brazilian Bt tolworthi strain (Btt01) was tested against Spodoptera frugiperda to assess the potential for biocontrol-product development based on more than one type of toxin/activity. Tests showed that 10(7) endospores mL(-1) caused >80% of larvae mortality, suggesting Btt01 may be used in similar concentrations as those of other Bt-based biopesticides. When it was applied to cornfields, a significant 60% reduction of larvae infestation was observed. However, bioassays with Btt01 SN revealed a thermostable toxic activity. Physicochemical characterization strongly suggests the presence of unwanted β-exotoxins, with isolate-specific temporal variation in its secretion. Knowledge of the temporal pattern of secretion/activity in culture for all forms of toxins produced by a single strain is required to both detect useful activities and avoid the potential lack of identification of undesirable toxins. These findings are discussed in the contexts of commercial Bt product development, advantages of multiple-activity strains, and care and handling recommended for large-scale fermentation systems. PMID:24854738

  3. Bacillus thuringiensis as a surrogate for Bacillus anthracis in aerosol research.

    PubMed

    Tufts, Jenia A M; Calfee, M Worth; Lee, Sang Don; Ryan, Shawn P

    2014-05-01

    Characterization of candidate surrogate spores prior to experimental use is critical to confirm that the surrogate characteristics are as closely similar as possible to those of the pathogenic agent of interest. This review compares the physical properties inherent to spores of Bacillus anthracis (Ba) and Bacillus thuringiensis (Bt) that impact their movement in air and interaction with surfaces, including size, shape, density, surface morphology, structure and hydrophobicity. Also evaluated is the impact of irradiation on the physical properties of both Bacillus species. Many physical features of Bt and Ba have been found to be similar and, while Bt is considered typically non-pathogenic, it is in the B. cereus group, as is Ba. When cultured and sporulated under similar conditions, both microorganisms share a similar cylindrical pellet shape, an aerodynamic diameter of approximately 1 μm (in the respirable size range), have an exosporium with a hairy nap, and have higher relative hydrophobicities than other Bacillus species. While spore size, morphology, and other physical properties can vary among strains of the same species, the variations can be due to growth/sporulation conditions and may, therefore, be controlled. Growth and sporulation conditions are likely among the most important factors that influence the representativeness of one species, or preparation, to another. All Bt spores may, therefore, not be representative of all Ba spores. Irradiated spores do not appear to be a good surrogate to predict the behavior of non-irradiated spores due to structural damage caused by the irradiation. While the use of Bt as a surrogate for Ba in aerosol testing appears to be well supported, this review does not attempt to narrow selection between Bt strains. Comparative studies should be performed to test the hypothesis that viable Ba and Bt spores will behave similarly when suspended in the air (as an aerosol) and to compare the known microscale characteristics

  4. INGESTION AND ADSORPTION OF 'BACILLUS THURINGIENSIS' SUBSP. 'ISRAELENSIS' BY 'GAMMARUS LACUSTRIS' IN THE LABORATORY

    EPA Science Inventory

    Several groups of Gammarus lacustris adults were exposed to solutions containing 0.5 and 5.0 mg of Bacillus thuringiensis subsp. israelensis per liter for 1- or 24-hour periods by using traditional static bioassay exposure procedures. The experiments verified that traditional exp...

  5. Mineralization of the Bacillus thuringiensis Cry1Ac endotoxin in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite a number of studies describing the fate of Bacillus thuringiensis insecticidal endotoxins in soil have been conducted in the past decade, conflicting information on persistence of this class of insecticidal toxins exists. In the present experiment, 14C from glucose was incorporated into the ...

  6. Screening Bacillus thuringiensis strains for toxicity against Manduca sexta and Plutella xylostella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Screening Bacillus thuringiensis (Bt) isolates or strains for toxicity has traditionally been performed with one bacterial isolate at time versus a specific insect. By testing of Bt strains in groups, we identified 28 of 147 Bt isolates as toxic to either diamondback moth, Plutella xylostella (L.),...

  7. Fulminant phlegmonitis of the esophagus, stomach, and duodenum due to Bacillus thuringiensis.

    PubMed

    Matsumoto, Hisatake; Ogura, Hiroshi; Seki, Masafumi; Ohnishi, Mitsuo; Shimazu, Takeshi

    2015-03-28

    We report a case of phlegmonitis of the esophagus, stomach, and duodenum in patient in an immunocompromised state. Culture of gastric juice and blood yielded Bacillus thuringiensis. This case showed that even low-virulence bacilli can cause lethal gastrointestinal phlegmonous gastritis in conditions of immunodeficiency. PMID:25834344

  8. Molecular markers to determine ecological fate of Bacillus thuringiensis subsp. kurstaki

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacillus thuringiensis (“Bt”) is a ubiquitous soil bacterium with entomopathogenic properties. One strain, Bt subsp. kurstaki (“Btk”), is highly toxic to lepidopteran larvae and used in many commercial products for biological pest control. We designed a set of DNA markers that successfully identifi...

  9. Recovery of Bacillus thuringiensis and insect toxic related strains from forest soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We attempted to recover Bacillus thuringiensis (Bt) from soil that had been sprayed two years prior with Bt for gypsy moth control. By amplifying the bacteria found in the soil on bacterial agar and feeding this diverse microbial population to tobacco hornworm larvae, 15 spore-forming bacteria from ...

  10. Phylogenetic distribution of phenotypic traits in bacillus thuringiensis analyzed by multilocus sequence typing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Strains from a collection of 3,639 diverse Bacillus thuringiensis isolates were classified based on phenotypic profiles resulting from six biochemical tests, including production of amylase (T), lecithinase (L), urease (U), acid from sucrose (S) and salicin (A), and the hydrolysis of esculin (E). St...

  11. Toxicity of "Bacillus thuringiensis var. Kurstaki" to the Painted Lady Butterfly, Vanessa cardui.

    ERIC Educational Resources Information Center

    Stalter, Richard; Nadal, Gerard; Kincaid, Dwight

    2000-01-01

    Reports the effects of Bacillus thuringiensis var. Kurstaki (BT), which is highly toxic, to a non-target lepidopteran, the Painted Lady butterfly. Indicates that BT kills some Painted Lady butterfly larvae at the lowest dilution tested after 48 hours. (ASK)

  12. Bacillus thuringiensis Cry3Aa toxin increases the susceptibility of Crioceris quatuordecimpunctata to Beauveria bassiana infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The spotted asparagus beetle, Crioceris quatuordecimpunctata (Coleoptera: Chrysomelidae), is one of the most devastating pests of asparagus in China and elsewhere. In this study, we investigated the interaction of Bacillus thuringiensis (Bt) Cry3Aa toxin and the entomopathogenic fungus Beauveria bas...

  13. Complete Genome Sequence of Bacillus thuringiensis Serovar Tolworthi Strain Pasteur Institute Standard

    PubMed Central

    Kanda, Kohzo; Nakashima, Kaede

    2015-01-01

    The genome sequence of Bacillus thuringiensis serovar tolworthi strain Pasteur Institute Standard was determined. The genome consists of a 5.9-Mb chromosome and eight plasmids, one of which is linear. The second largest plasmid (293 kb) carries the genes encoding insecticidal proteins. PMID:26139717

  14. Transcriptome of the gypsy moth (Lymantria dispar) larval midgut in response to infection by Bacillus thuringiensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transcriptomic profiles of the lepidopteran insect pest Lymantria dispar (gypsy moth) were characterized in the larval midgut in response to infection by the biopesticide Bacillus thuringiensis kurstaki. RNA-Seq approaches were used to define a set of 49,613 assembled transcript sequences, of which...

  15. A Novel Tenebrio molitor Cadherin is a Functional Receptor for Bacillus thuringiensis Toxin Cry3Aa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cry toxins produced by the bacterium Bacillus thuringiensis (Bt) are effective biological insecticides. Cadherin-like proteins have been reported as functional Cry1A toxin receptors in Lepidoptera. We present the first report demonstrating a functional interaction between the coleopteran-specific ...

  16. COMPARATIVE ANALYSIS OF PROTEINASE ACTIVITIES OF BACILLUS THURINGIENSIS-RESISTANT AND -SUSCEPTIBLE OSTRINIA NUBILALIS (LEPIDOPTERA: CRAMBIDAE)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proteinase activities were compared in soluble and membrane fractions of gut tissues of Bacillus thuringiensis-resistant and -susceptible Ostrinia nubilalis larvae. The soluble trypsin-like proteinase activity of the resistant strain was reduced 56%, significantly lower than that of the susceptibl...

  17. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. 180.1107 Section 180.1107 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES...

  18. IMPACT OF BT ( BACILLUS THURINGIENSIS ) CROPS ON BAT ACTIVITY IN SOUTH TEXAS AGROECOSYSTEMS

    EPA Science Inventory

    The widespread adoption of transgenic insecticidal crops raises concerns that nontarget species may be harmed and food webs disrupted. The goal of this research is to determine how transgenic Bt (Bacillus thuringiensis) crops impact the activity of Brazilian freetailed bats (Tada...

  19. The occurrence of Photorhabdus-like toxin complexes in Bacillus thuringiensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recently, genomic sequencing of a Bacillus thuringiensis (Bt) isolate from our collection revealed the presence of an apparent operon encoding an insecticidal toxin complex (Tca) similar to that first described from the entomopathogen Photorhabdus luminescens. To determine whether these genes are w...

  20. VERTEBRATE TOXICOLOGY OF THE SOLUBILIZED PROTEINS OF BACILLUS THURINGIENSIS SUBSP. ISRAELENSIS

    EPA Science Inventory

    This review summarizes the studies done with the mammalian toxic Bacillus thuringiensis subsp. israelensis (Bti) 28 kDa cytA protein. The data is relevant to hazard identification studies with bacterial pesticides. The data shows that cytA produces lethal physiological changes in...

  1. EFFECT OF REMOVAL OF THE CYTOLYTIC FACTOR OF 'BACILLUS THURINGIENSIS' SUBSP. 'ISRAELENSIS' ON MOSQUITO TOXICITY

    EPA Science Inventory

    Solubilized crystal protein of Bacillus thuringiensis subsp. israelensis was fractionated by affinity chromotography using a monoclonal antibody directed against the crystal's 28 kDa peptide. The 28 kDa peptide ws found to be relatively nontoxic to mosquito larvae although it doe...

  2. INTERACTIONS BETWEEN BACILLUS THURINGIENSIS SUBSP. ISRAELENSIS AND FATHEAD MINNOWS, PIMEPHALES PROMELAS RAFINESQUE, UNDER LABORATORY CONDITIONS

    EPA Science Inventory

    Interactions between Bacillus thuringiensis subsp. israelensis and fathead minnows, Pimephales promelas, were studied in laboratory exposures to two commercial formulations, Vectobac-G and Mosquito Attack. ortality among fatheads exposed to 2.0 x 10 6 to 6.5 x 10 6 CFU/ml with bo...

  3. BACILLUS THURINGIENSIS VAR. KURSTAKI AFFECTS A BENEFICIAL INSECT, THE CINNABAR MOTH (LEPIDOPTERA: ARCTIIDAE)

    EPA Science Inventory

    The microbial insecticide bacillus thuringiensis Berliner var. kurstaki is used to control forest pests in regions where tansy ragwort, Senecio jacobaea L. occurs. iological control of this noxious weed may be compromised if the cinnabar moth, Tyria jacobaeae (L), is susceptible ...

  4. INSECT RESISTANCE TO BACILLUS THURINGIENSIS: ALTERATIONS IN THE INDIANMEAL MOTH LARVAL GUT PROTEOME

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect resistance to the Cry toxins of Bacillus thuringiensis (Bt) has been examined previously using a number of traditional biochemical and molecular techniques. In this study, we utilized a proteomic approach involving two-dimensional differential gel electrophoresis, mass spectrometry and funct...

  5. 40 CFR 180.1011 - Viable spores of the microorganism Bacillus thuringiensis Berliner; exemption from the...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Viable spores of the microorganism Bacillus thuringiensis Berliner; exemption from the requirement of a tolerance. 180.1011 Section 180.1011 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL...

  6. ANALYSIS OF MIDGUT PROTEINASES FROM BACILLUS THURINGIENSIS-SUSCEPTIBLE AND -RESISTANT HELIOTHIS VIRESCENS (LEPIDOPTERA: NOCTUIDAE)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insects with altered proteinases can avoid intoxication by Bacillus thuringiensis (Bt) toxins. Therefore, proteinase activities from gut extracts of Bt-susceptible (YDK) and -resistant (YHD2-B, CXC and KCBhyb) H. virescens strains were compared. The overall pH of gut extracts from YDK and CXC were...

  7. Screen of Bacillus thuringiensis toxins for transgenic rice to control Sesamia inferens and Chilo suppressalis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic rice to control stem borer damage is under development in China. To assess the potential of Bacillus thuringiensis (Bt) transgenes in stem borer control, the toxicity of five Bt protoxins (Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba and Cry1Ca) against two rice stem borers, Sesamia inferens (pink stem...

  8. Binding of Bacillus thuringiensis toxin CrylAc to multiple sites of cadherin in pink bollworm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toxins from Bacillus thuringiensis (Bt) are widely used for pest control. In particular, Bt toxin Cry lAc produced by transgenic cotton kills some key lepidopteran pests. We found that CrylAc binds to recombinant peptides corresponding to extracellular regions of a cadherin protein (BtR) in a major ...

  9. Insecticidal toxins from Bacillus thuringiensis subsp. kenyae: gene cloning and characterization and comparison with B. thuringiensis subsp. kurstaki CryIA(c) toxins.

    PubMed Central

    Von Tersch, M A; Robbins, H L; Jany, C S; Johnson, T B

    1991-01-01

    Genes encoding insecticidal crystal proteins were cloned from three strains of Bacillus thuringiensis subsp. kenyae and two strains of B. thuringiensis subsp. kurstaki. Characterization of the B. thuringiensis subsp. kenyae toxin genes showed that they are most closely related to cryIA(c) from B. thuringiensis subsp. kurstaki. The cloned genes were introduced into Bacillus host strains, and the spectra of insecticidal activities of each Cry protein were determined for six pest lepidopteran insects. CryIA(c) proteins from B. thuringiensis subsp. kenyae are as active as CryIA(c) proteins from B. thuringiensis subsp. kurstaki against Trichoplusia ni, Lymantria dispar, Heliothis zea, and H. virescens but are significantly less active against Plutella xylostella and, in some cases, Ostrinia nubilalis. The sequence of a cryIA(c) gene from B. thuringiensis subsp. kenyae was determined (GenBank M35524) and compared with that of cryIA(c) from B. thuringiensis subsp. kurstaki. The two genes are more than 99% identical and show seven amino acid differences among the predicted sequences of 1,177 amino acids. Images PMID:2014985

  10. Chemical modulators of the innate immune response alter gypsy moth larval susceptibility to Bacillus thuringiensis

    PubMed Central

    2010-01-01

    Background The gut comprises an essential barrier that protects both invertebrate and vertebrate animals from invasion by microorganisms. Disruption of the balanced relationship between indigenous gut microbiota and their host can result in gut bacteria eliciting host responses similar to those caused by invasive pathogens. For example, ingestion of Bacillus thuringiensis by larvae of some species of susceptible Lepidoptera can result in normally benign enteric bacteria exerting pathogenic effects. Results We explored the potential role of the insect immune response in mortality caused by B. thuringiensis in conjunction with gut bacteria. Two lines of evidence support such a role. First, ingestion of B. thuringiensis by gypsy moth larvae led to the depletion of their hemocytes. Second, pharmacological agents that are known to modulate innate immune responses of invertebrates and vertebrates altered larval mortality induced by B. thuringiensis. Specifically, Gram-negative peptidoglycan pre-treated with lysozyme accelerated B. thuringiensis-induced killing of larvae previously made less susceptible due to treatment with antibiotics. Conversely, several inhibitors of the innate immune response (eicosanoid inhibitors and antioxidants) increased the host's survival time following ingestion of B. thuringiensis. Conclusions This study demonstrates that B. thuringiensis infection provokes changes in the cellular immune response of gypsy moth larvae. The effects of chemicals known to modulate the innate immune response of many invertebrates and vertebrates, including Lepidoptera, also indicate a role of this response in B. thuringiensis killing. Interactions among B. thuringiensis toxin, enteric bacteria, and aspects of the gypsy moth immune response may provide a novel model to decipher mechanisms of sepsis associated with bacteria of gut origin. PMID:20423490

  11. [Biology of two lysogenic phages from Bacillus thuringiensis MZ1].

    PubMed

    Liao, Wei; Sun, Fan; Song, Shao-yun; Shi, Wei; Pang, Yi

    2007-02-01

    A Bacillus thuringiensis (Bt) fermentative strain MZ1 (subsp. kurstaki) , from a company in Meixian County of Guangdong Province, produce toxins during sporulation and are extensively used in the field to control pest insects (Lepidoptera) in China. But some unknown or random factors that inhibited or stopped B. t growth in the fermentation can be regarded as reflecting the exist of lysogenic phage. Therefore, strain MZI and its lysogenic phages were studied in this paper. With indicator strain ZK1, two kind of phage plaques, one with about 3mm diameter and the other with about 1mm diameter, can be observed after strain MZ1 cultured in plates or flasks was induced by mitomycin C. Then, two lysogenic phages, namely MZTP01 and MZTP02, were isolated and characterized in biology. They belonged to family Siphoviridae, which had icosahedral heads (MZTP01 :82nm x 85nm; MZTP02: 75nm x 55nm) and long tails (MZTP01: 220nm x 18nm; MZTP02: 183nm x 12nm) without flexibility. Host range examination showed that six and seven (including indicator strain ZKl) out of 113 B. t strains saved in our laboratory were sensitive to MZTP01 and MZTP02, respectively. MZTP01 was more stable than MZTP02 against pH value, ultraviolet and heat treatment, but contrary against organic solvents. For MZTP01 and MZTP02, K values in the neutralization reactions were 45 and 326, respectively. Both phages had no relationship in their antigenicity. Burst size of phage MZTP02 was 175, two times more than that of MZTP01. Latent time of MZTP02 was 40min, one times shorter than that of MZTP01. It was suggested that both phages DNA be linear dsDNA through the typical absorption curves, reaction with diphenylamine, DNase sensitivity and acridine orange staining. And this was in good accord with the previous findings that all tailed phages being dsDNA moleculars. The genomic DNA and their restriction maps showed that both molecular weights should be between 9.4 - 23kb. Both phage genomic DNAs were digested by

  12. Genomic and transcriptomic insights into the efficient entomopathogenicity of Bacillus thuringiensis

    PubMed Central

    Zhu, Lei; Peng, Donghai; Wang, Yueying; Ye, Weixing; Zheng, Jinshui; Zhao, Changming; Han, Dongmei; Geng, Ce; Ruan, Lifang; He, Jin; Yu, Ziniu; Sun, Ming

    2015-01-01

    Bacillus thuringiensis has been globally used as a microbial pesticide for over 70 years. However, information regarding its various adaptions and virulence factors and their roles in the entomopathogenic process remains limited. In this work, we present the complete genomes of two industrially patented Bacillus thuringiensis strains (HD-1 and YBT-1520). A comparative genomic analysis showed a larger and more complicated genome constitution that included novel insecticidal toxicity-related genes (ITRGs). All of the putative ITRGs were summarized according to the steps of infection. A comparative genomic analysis showed that highly toxic strains contained significantly more ITRGs, thereby providing additional strategies for infection, immune evasion, and cadaver utilization. Furthermore, a comparative transcriptomic analysis suggested that a high expression of these ITRGs was a key factor in efficient entomopathogenicity. We identified an active extra urease synthesis system in the highly toxic strains that may aid B. thuringiensis survival in insects (similar to previous results with well-known pathogens). Taken together, these results explain the efficient entomopathogenicity of B. thuringiensis. It provides novel insights into the strategies used by B. thuringiensis to resist and overcome host immune defenses and helps identify novel toxicity factors. PMID:26411888

  13. Response of Heliothis virescens (Lepidoptera: Noctuidae) strains to Bacillus thuringiensis Cry1Ac incorporated into different insect artificial diets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Susceptibility to the Cry1Ac toxin from Bacillus thuringiensis in Heliothis virescens is usually measured by performing bioassays under laboratory conditions. Currently there is great interest and research devoted to this insect because it is one of the main targets of B. thuringiensis-expressing tr...

  14. Analysis of Bacillus thuringiensis Population Dynamics and Its Interaction With Pseudomonas fluorescens in Soil

    PubMed Central

    Rojas-Ruiz, Norma Elena; Sansinenea-Royano, Estibaliz; Cedillo-Ramirez, Maria Lilia; Marsch-Moreno, Rodolfo; Sanchez-Alonso, Patricia; Vazquez-Cruz, Candelario

    2015-01-01

    Background: Bacillus thuringiensis is the most successful biological control agent, however, studies so far have shown that B. thuringiensis is very sensitive to environmental factors such as soil moisture and pH. Ultraviolet light from the sun had been considered as the main limiting factor for its persistence in soil and it has recently been shown that the antagonism exerted by other native soil organisms, such as Pseudomonas fluorescens, is a determining factor in the persistence of this bacterium under in vitro culture conditions. Objectives: The aim of the present investigation was to analyze the population dynamics of B. thuringiensis and its interaction with P. fluorescens using microbiological and molecular methods in soil, under different conditions, and to determinate the effect of nutrients and moisture on its interaction. Materials and Methods: The monitoring was performed by microbiological methods, such as viable count of bacteria, and molecular methods such as Polymerase Chain Reaction (PCR) and hybridization, using the direct extraction of DNA from populations of inoculated soil. Results: The analysis of the interaction between B. thuringiensis and P. fluorescens in soil indicated that the disappearance of B. thuringiensis IPS82 is not dependent on the moisture but the composition of nutrients that may be affecting the secretion of toxic compounds in the environment of P. fluorescens. The results showed that the recovered cells were mostly spores and not vegetative cells in all proved treatments. The molecular methods were effective for monitoring bacterial population inoculated in soil. Conclusions: Bacillus thuringiensis is very sensitive to the interaction of P. fluorescens, however is capable to survive in soil due to its capacity of sporulate. Some of the cells in the form of spores germinated and folded slightly and remained in a constant cycle of sporulation and germination. This confirms that B. thuringiensis IPS82 can germinate, grow and

  15. Effects of four entomopathogenic nematode species on fitness costs of pink bollworm resistance to Bacillus thuringiensis toxin Cry1Ac

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evolution of resistance by pests can reduce the efficacy of transgenic crops that produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt). However, fitness costs can slow the evolution of resistance. We tested whether four species of entomopathogenic nematodes (Steinernematidae ...

  16. Decreased Toxicity of Bacillus thuringiensis subsp. israelensis to Mosquito Larvae after Contact with Leaf Litter

    PubMed Central

    Stalinski, Renaud; Kersusan, Dylann; Veyrenc, Sylvie; David, Jean-Philippe; Reynaud, Stéphane; Després, Laurence

    2012-01-01

    Bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing Cry and Cyt proteins, which are toxic for mosquito larvae. Nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. In the present work, we investigated the behavior of B. thuringiensis subsp. israelensis toxic crystals sprayed on leaf litter. In the presence of leaf litter, a 60% decrease in the amount of Cyt toxin detectable by immunology (enzyme-linked immunosorbent assays [ELISAs]) was observed, while the respective proportions of Cry toxins were not affected. The toxicity of Cry toxins toward Aedes aegypti larvae was not affected by leaf litter, while the synergistic effect of Cyt toxins on all B. thuringiensis subsp. israelensis Cry toxins was decreased by about 20% when mixed with leaf litter. The toxicity of two commercial B. thuringiensis subsp. israelensis strains (VectoBac WG and VectoBac 12AS) and a laboratory-produced B. thuringiensis subsp. israelensis strain decreased by about 70% when mixed with leaf litter. Taken together, these results suggest that Cyt toxins interact with leaf litter, resulting in a decreased toxicity of B. thuringiensis subsp. israelensis in litter-rich environments and thereby dramatically reducing the efficiency of mosquitocidal treatments. PMID:22610426

  17. A novel metalloproteinase virulence factor is involved in Bacillus thuringiensis pathogenesis in nematodes and insects.

    PubMed

    Peng, Donghai; Lin, Jian; Huang, Qiong; Zheng, Wen; Liu, Guoqiang; Zheng, Jinshui; Zhu, Lei; Sun, Ming

    2016-03-01

    The Gram-positive soil bacterium Bacillus thuringiensis has been developed as the leading microbial insecticide for years. The pathogenesis of B. thuringiensis requires common extracellular factors that depend on the PlcR regulon, which regulates a large number of virulence factors; however, the precise role of many of these proteins is not known. In this study, we describe the complete lifecycle of a nematicidal B. thuringiensis strain in the free living nematode Caenorhabditis elegans using in vitro and in vivo molecular techniques to follow host and bacterial effectors during the infection process. We then focus on the metalloproteinase ColB, a collagenase, which was found highly important for destruction of the intestine thereby facilitates the adaptation and colonization of B. thuringiensis in C. elegans. In vivo green fluorescent protein (GFP) reporter-gene studies showed that ColB expression is highly induced and regulated by the global activator PlcR. Finally, we demonstrated that ColB also takes part in B. thuringiensis virulence in an insect model following injection and oral infection. Indeed, addition of purified ColB accelerates the action of Cry toxin proteins in insects, too. These results give novel insights into host adaptation for B. thuringiensis and other B. cereus group bacteria and highlight the role of collagenase metalloproteases to synergize infection process. PMID:26995589

  18. Activation of MAP kinase pathways in Galleria mellonella infected with Bacillus thuringiensis.

    PubMed

    Wojda, Iwona; Koperwas, Konrad; Jakubowicz, Teresa

    2014-01-01

    We followed changes in the level of phospho-MAP kinases in the greater wax moth Galleria mellonella after infection with Bacillus thuringiensis. We observed an enhanced level of phosphorylated p38 and JNK in fat bodies of the infected larvae. In hemocytes, injection of B. thuringiensis caused the highest increase in phospho-JNK, however, all pathways were activated after aseptic injection. We report that Galleria mellonella larvae exposed to heat shock before infection showed an enhanced level of phosphorylated JNK in fat body. This finding is relevant in the light of our previous reports, which submit evidence that pre-shocked animals are more resistant to infection. PMID:24455757

  19. Overexpression of the Bacillus thuringiensis (Bt) Cry2Aa2 protein in chloroplasts confers resistance to plants against susceptible and Bt-resistant insects

    PubMed Central

    Kota, Madhuri; Daniell, Henry; Varma, Sam; Garczynski, Stephen F.; Gould, Fred; Moar, William J.

    1999-01-01

    Evolving levels of resistance in insects to the bioinsecticide Bacillus thuringiensis (Bt) can be dramatically reduced through the genetic engineering of chloroplasts in plants. When transgenic tobacco leaves expressing Cry2Aa2 protoxin in chloroplasts were fed to susceptible, Cry1A-resistant (20,000- to 40,000-fold) and Cry2Aa2-resistant (330- to 393-fold) tobacco budworm Heliothis virescens, cotton bollworm Helicoverpa zea, and the beet armyworm Spodoptera exigua, 100% mortality was observed against all insect species and strains. Cry2Aa2 was chosen for this study because of its toxicity to many economically important insect pests, relatively low levels of cross-resistance against Cry1A-resistant insects, and its expression as a protoxin instead of a toxin because of its relatively small size (65 kDa). Southern blot analysis confirmed stable integration of cry2Aa2 into all of the chloroplast genomes (5,000–10,000 copies per cell) of transgenic plants. Transformed tobacco leaves expressed Cry2Aa2 protoxin at levels between 2% and 3% of total soluble protein, 20- to 30-fold higher levels than current commercial nuclear transgenic plants. These results suggest that plants expressing high levels of a nonhomologous Bt protein should be able to overcome or at the very least, significantly delay, broad spectrum Bt-resistance development in the field. PMID:10051556

  20. Microcalorimetric investigation on the growth model and the protein yield of Bacillus thuringiensis.

    PubMed

    Xiaoyan, Lin; Yi, Liu; Peng, Liu; Songsheng, Qu; Ziniu, Yu

    2004-06-30

    A novel microcalorimetric technique based on the bacterial heat output was applied to evaluate the special growth model, the protein expression and the generation time of Bacillus thuringiensis for the first time. The thermogenic curves of the aerobic metabolism of B. thuringiensis strains YBT-833, YBT-1520 and YBT-833-2-1 were determined by using an LKB-2277 BioActivity Monitor. The analysis of the thermogenic curves indicated both the mutant strain and the wild-type strains followed the same linear growth model during sporulation. The metabolism heat output revealed heat output was correlated to the yield of the insecticidal crystal proteins (ICPs) very well, the more protein product, and the less heat output. Based on the data acquired, we proposed that this method could be a useful tool in monitoring the fermentation of B. thuringiensis. PMID:15165757

  1. Ubiquity of parasporin-1 producers in Bacillus thuringiensis natural populations of Japan

    NASA Astrophysics Data System (ADS)

    Uemori, Akiko; Maeda, Minoru; Yasutake, Koichi; Ohgushi, Akira; Kagoshima, Kumiko; Mizuki, Eiichi; Ohba, Michio

    2007-01-01

    Parasporin, a Bacillus thuringiensis parasporal protein, is unique in having a strong cytocidal activity preferential for human cancer cells. In this study, we characterized parasporin activities associated with three novel geographical isolates of B. thuringiensis. Parasporal inclusion proteins of the three isolates were highly toxic to human uterus cervix cancer cells (HeLa), but not to non-cancer uterine smooth muscle cells (UtSMC). Inclusions of the isolates lacked insect toxicity and hemolytic activity against sheep erythrocytes. Ouchterlony immunodiffusion tests revealed that the proteins of the three isolates are immunologically closely related to parasporin-1 (Cry31A), but dissimilar to the three other existing parasporin groups. Our results provide evidence that the parasporin-1-producing organism is a common member in B. thuringiensis populations occurring in natural environments of Japan.

  2. Comparison of quantitative PCR and culture-based methods for evaluating dispersal of Bacillus thuringiensis endospores at a bioterrorism hoax crime scene.

    PubMed

    Crighton, Taryn; Hoile, Rebecca; Coleman, Nicholas V

    2012-06-10

    Since the anthrax mail attacks of 2001, law enforcement agencies have processed thousands of suspicious mail incidents globally, many of which are hoax bioterrorism threats. Bio-insecticide preparations containing Bacillus thuringiensis (Bt) spores have been involved in several such threats in Australia, leading to the requirement for rapid and sensitive detection techniques for this organism, a close relative of Bacillus anthracis. Here we describe the development of a quantitative PCR (qPCR) method for the detection of Bt crystal toxin gene cry1, and evaluation of the method's effectiveness during a hoax bioterrorism event in 2009. When combined with moist wipe sampling, the cry1 qPCR was a rapid, reliable, and sensitive diagnostic tool for detecting and quantifying Bt contamination, and mapping endospore dispersal within a mail sorting facility. Results from the cry1 qPCR were validated by viable counts of the same samples on Bacillus-selective agar (PEMBA), which revealed a similar pattern of contamination. Extensive and persistent contamination of the facility was detected, both within the affected mailroom, and extending into office areas up to 30m distant from the source event, emphasising the need for improved containment procedures for suspicious mail items, both during and post-event. The cry1 qPCR enables detection of both viable and non-viable Bt spores and cells, which is important for historical crime scenes or scenes subjected to decontamination. This work provides a new rapid method to add to the forensics toolbox for crime scenes suspected to be contaminated with biological agents. PMID:22227150

  3. Structural Insights into Bacillus thuringiensis Cry, Cyt and Parasporin Toxins

    PubMed Central

    Xu, Chengchen; Wang, Bi-Cheng; Yu, Ziniu; Sun, Ming

    2014-01-01

    Since the first X-ray structure of Cry3Aa was revealed in 1991, numerous structures of B. thuringiensis toxins have been determined and published. In recent years, functional studies on the mode of action and resistance mechanism have been proposed, which notably promoted the developments of biological insecticides and insect-resistant transgenic crops. With the exploration of known pore-forming toxins (PFTs) structures, similarities between PFTs and B. thuringiensis toxins have provided great insights into receptor binding interactions and conformational changes from water-soluble to membrane pore-forming state of B. thuringiensis toxins. This review mainly focuses on the latest discoveries of the toxin working mechanism, with the emphasis on structural related progress. Based on the structural features, B. thuringiensis Cry, Cyt and parasporin toxins could be divided into three categories: three-domain type α-PFTs, Cyt toxin type β-PFTs and aerolysin type β-PFTs. Structures from each group are elucidated and discussed in relation to the latest data, respectively. PMID:25229189

  4. Ecological consequences of ingestion of Bacillus cereus on Bacillus thuringiensis infections and on the gut flora of a lepidopteran host.

    PubMed

    Raymond, Ben; Lijek, Rebeccah S; Griffiths, Robert I; Bonsall, Michael B

    2008-09-01

    The Bacillus cereus group comprises a diverse array of non-pathogenic bacteria as well as pathogens such as Bacillus thuringiensis. Their spores are found together in soil and leaves and are therefore likely to commonly interact within hosts. Mixed infections of pathogenic B. thuringiensis and non-pathogenic strains have been little studied, despite their potential impact on biological control and the evolutionary ecology of virulence. Antibiotic secreting strains of B. cereus have been shown to be able to synergize B. thuringiensis (Bt) infections. We explored the ecology of these mixed infections more broadly in the diamondback moth (DBM). We tested whether antibiotic-expressing B. cereus can synergize Bt infections initiated with spores, investigated whether ingestion of antibiotic-expressing B. cereus had any consequences for the larval gut flora and whether synergistic interactions with B. cereus increase Bt reproduction. Ingestion of high-antibiotic secreting B. cereus synergized infections of B. thuringiensis in diamondback moth larvae, but at a lower level than previously reported. Coinfection also increased slightly the number of Bt spores found in cadavers. Culture independent analysis of gut homogenates indicated that ingestion of an antibiotic-expressing strain of B. cereus reduced the abundance of the gut flora and led to gut communities being dominated bacteria with DGGE profiles very similar to pure B. cereus cultures. Ingestion of B. cereus, regardless of genotype, reduced densities of an enteric isolate of Enterobacter sp. These findings support the hypothesis that antibiotic secretion in the gut synergizes B. thuringiensis infections by reducing the abundance of the commensal gut flora and facilitating invasion by bacteria in the B. cereus group. PMID:18533180

  5. Effect of chemical additives on Bacillus thuringiensis (Bacillales: Bacillaceae) against Plutella xylostella (Lepidoptera: Pyralidae).

    PubMed

    Zhang, L; Qiu, S; Huang, T; Huang, Z; Xu, L; Wu, C; Gelbic, I; Guan, X

    2013-06-01

    To examine the effect of chemical additives on Bacillus thuringiensis (Berliner) against Plutella xylostella (L.), inorganic salts, nitrogenous compounds, protein solubilizing agents, and organic acids were selected and tested. The chosen materials are low in cost and environmentally safe. Results show that many inorganic salts can increase the activity of B. thuringiensis in a range of 1.31- to 3.08-fold. These include calcium acetate, calcium chloride, calcium hydroxide, calcium sulfate, calcium carbonate, sodium carbonate, sodium acetate, potassium hydroxide, potassium carbonate, potassium acetate, magnesium chloride, magnesium sulfate, and zinc sulfate. Nitrogenous compounds, including peptone, sodium nitrate, and ammonium nitrate, can enhance the activity of B. thuringiensis 1.62-, 1.32-, and 1.37-fold, respectively. Among the protein solubilizing agents, EDTA, urea, mercaptoethanol and dipotassium hydrogen phosphate increased the activity of B. thuringiensis 1.62- to 2.34-fold. Among the organic acids, maleic and citric acids boosted the activity 1.45- and 1.55-fold, respectively. Meanwhile, sodium benzoate and resorcinol led to 1.74- and 1.44-fold activity gains, respectively. Use of appropriate additives could provide great benefit not only in reducing the costs for field applications of biological insecticides but also by boosting the efficacy of B. thuringiensis. PMID:23865169

  6. Bacillus thuringiensis colonises plant roots in a phylogeny-dependent manner.

    PubMed

    Vidal-Quist, J Cristian; Rogers, Hilary J; Mahenthiralingam, Eshwar; Berry, Colin

    2013-12-01

    Although much is known about the pathology of Bacillus thuringiensis against invertebrates, current understanding of its natural ecology is limited. This study evaluated the biodiversity of B. thuringiensis in relation to its interaction with plants. Phylogenetic relationships between 44 reference and field-collected strains, determined using 16S rRNA and gyrB gene sequences, revealed a high degree of variability, similar to that found in databases. An Arabidopsis thaliana in vitro inoculation model was developed to screen the ability of B. thuringiensis to colonise roots. Significant colonisation differences up to 91-fold were observed between strains, and correlation between strain phylogeny and colonisation was found. The genetics and biochemistry of auxin production; presence of the gene encoding indole pyruvate decarboxylase; and the abilities of Bt strains to swarm, grow in rich/minimal media and affect root growth differed between the strains, but only auxin production correlated significantly with ability to colonise roots. Co-inoculation with Burkholderia phytofirmans PsJN or Pseudomonas fluorescens SBW25 produced no effect on B. thuringiensis colonisation levels, regardless of the co-inoculant. Similarly, root colonisation of A. thaliana mutants impaired in plant defences was not significantly higher compared with controls. This is the first systematic and phylogenetic evaluation of B. thuringiensis interaction with plants. PMID:23822207

  7. Multi-method approach for characterizing the interaction between Fusarium verticillioides and Bacillus thuringiensis subsp. Kurstaki.

    PubMed

    Rocha, Liliana O; Tralamazza, Sabina Moser; Reis, Gabriela M; Rabinovitch, Leon; Barbosa, Cynara B; Corrêa, Benedito

    2014-01-01

    Bacterial antagonists used as biocontrol agents represent part of an integrated management program to reduce pesticides in the environment. Bacillus thuringiensis is considered a good alternative as a biocontrol agent for suppressing plant pathogens such as Fusarium. In this study, we used microscopy, flow cytometry, indirect immunofluorescence, and high performance liquid chromatography to determine the interaction between B. thuringiensis subsp. kurstaki LFB-FIOCRUZ (CCGB) 257 and F. verticillioides MRC 826, an important plant pathogen frequently associated with maize. B. thuringiensis showed a strong in vitro suppressive effect on F. verticillioides growth and inhibited fumonisin production. Flow cytometry analysis was found to be adequate for characterizing the fungal cell oscillations and death during these interactions. Further studies of the antagonistic effect of this isolate against other fungi and in vivo testing are necessary to determine the efficacy of B. thuringiensis subsp. kurstaki in controlling plant pathogens. This is the first report on the use of flow cytometry for quantifying living and apoptotic F. verticillioides cells and the B. thuringiensis Cry 1Ab toxin. PMID:24739804

  8. Multi-Method Approach for Characterizing the Interaction between Fusarium verticillioides and Bacillus thuringiensis Subsp. Kurstaki

    PubMed Central

    Rocha, Liliana O.; Tralamazza, Sabina Moser.; Reis, Gabriela M.; Rabinovitch, Leon; Barbosa, Cynara B.; Corrêa, Benedito

    2014-01-01

    Bacterial antagonists used as biocontrol agents represent part of an integrated management program to reduce pesticides in the environment. Bacillus thuringiensis is considered a good alternative as a biocontrol agent for suppressing plant pathogens such as Fusarium. In this study, we used microscopy, flow cytometry, indirect immunofluorescence, and high performance liquid chromatography to determine the interaction between B. thuringiensis subsp. kurstaki LFB-FIOCRUZ (CCGB) 257 and F. verticillioides MRC 826, an important plant pathogen frequently associated with maize. B. thuringiensis showed a strong in vitro suppressive effect on F. verticillioides growth and inhibited fumonisin production. Flow cytometry analysis was found to be adequate for characterizing the fungal cell oscillations and death during these interactions. Further studies of the antagonistic effect of this isolate against other fungi and in vivo testing are necessary to determine the efficacy of B. thuringiensis subsp. kurstaki in controlling plant pathogens. This is the first report on the use of flow cytometry for quantifying living and apoptotic F. verticillioides cells and the B. thuringiensis Cry 1Ab toxin. PMID:24739804

  9. The Pathogenomic Sequence Analysis of B. cereus and B. Thuringiensis isolates closely related to Bacillus anthracis

    SciTech Connect

    Han, C S; Xie, G; Challacombe, J F; Altherr, M R; Bhotika, S S; Bruce, D; Campbell, C S; Campbell, M L; Chen, J; Chertkov, O; Cleland, C; Dimitrijevic-Bussod, M; Doggett, N A; Fawcett, J J; Glavina, T; Goodwin, L A; Hill, K K; Hitchcock, P; Jackson, P J; Keim, P; Kewalramani, A R; Longmire, J; Lucas, S; Malfatti, S; McMurry, K; Meincke, L J; Misra, M; Moseman, B L; Mundt, M; Munk, A C; Okinaka, R T; Parson-Quintana, B; Reilly, L P; Richardson, P; Robinson, D L; Rubin, E; Saunders, E; Tapia, R; Tesmer, J G; Thayer, N; Thompson, L S; Tice, H; Ticknor, L O; Wills, P L; Gilna, P; Brettin, T S

    2005-10-12

    The sequencing and analysis of two close relatives of Bacillus anthracis are reported. AFLP analysis of over 300 isolates of B. cereus, B. thuringiensis and B. anthracis identified two isolates as being very closely related to B. anthracis. One, a B. cereus, BcE33L, was isolated from a zebra carcass in Nambia; the second, a B. thuringiensis, 97-27, was isolated from a necrotic human wound. The B. cereus appears to be the closest anthracis relative sequenced to date. A core genome of over 3,900 genes was compiled for the Bacillus cereus group, including B anthracis. Comparative analysis of these two genomes with other members of the B. cereus group provides insight into the evolutionary relationships among these organisms. Evidence is presented that differential regulation modulates virulence, rather than simple acquisition of virulence factors. These genome sequences provide insight into the molecular mechanisms contributing to the host range and virulence of this group of organisms.

  10. Bacillus thuringiensis var. tenebrionis control of synanthropic mites (Acari: Acaridida) under laboratory conditions.

    PubMed

    Erban, Tomas; Nesvorna, Marta; Erbanova, Michaela; Hubert, Jan

    2009-12-01

    Bacillus thuringiensis (Bt) toxins present a potential for control of pest mites. Information concerning the effect of Bt and its possible application to the biocontrol of synathropic mites is rare. The toxic effect of Bacillus thuringiensis var. tenebrionis producing Cry3A toxin was tested on the mites Acarus siro L., Tyrophagus putrescentiae (Schrank), Dermatophagoides farinae Hughes, and Lepidoglyphus destructor (Schrank) via feeding tests. Fifty mites were reared on Bt additive diets in concentrations that ranged from 0 to 100 mg g(-1) under optimal conditions for their development. After 21 days, the mites were counted and the final populations were analyzed using a polynomial regression model. The Bt diet suppressed population growth of the four mite species. The fitted doses of Bt for 50% suppression of population growth were diets ranging from 25 to 38 mg g(-1). There were no remarkable differences among species. Possible applications of Bt for the control of synanthropic mites are discussed. PMID:19381844

  11. Production of a Thermostable and Alkaline Chitinase by Bacillus thuringiensis subsp. kurstaki Strain HBK-51

    PubMed Central

    Kuzu, Secil Berna; Güvenmez, Hatice Korkmaz; Denizci, Aziz Akin

    2012-01-01

    This paper reports the isolation and identification of chitinase-producing Bacillus from chitin-containing wastes, production of a thermostable and alkaline chitinasese, and enzyme characterization. Bacillus thuringiensis subsp. kurstaki HBK-51 was isolated from soil and was identified. Chitinase was obtained from supernatant of B. thuringiensis HBK-51 strain and showed its optimum activity at 110°C and at pH 9.0. Following 3 hours of incubation period, the enzyme showed a high level of activity at 110°C (96% remaining activity) and between pH 9.0 and 12.0 (98% remaining activity). Considering these characteristics, the enzyme was described as hyperthermophile-thermostable and highly alkaline. Two bands of the enzyme weighing 50 and 125 kDa were obtained following 12% SDS-PAGE analyses. Among the metal ions and chemicals used, Ni2+ (32%), K+ (44%), and Cu2+ (56%) increased the enzyme activity while EDTA (7%), SDS (7%), Hg2+ (11%), and ethyl-acetimidate (20%) decreased the activity of the enzyme. Bacillus thuringiensis subsp. kurstaki HBK-51 is an important strain which can be used in several biotechnological applications as a chitinase producer. PMID:23304523

  12. Cloning, Sequencing, and Expression of the Chitinase Gene chiA74 from Bacillus thuringiensis

    PubMed Central

    Barboza-Corona, J. Eleazar; Nieto-Mazzocco, Elizabeth; Velázquez-Robledo, Rocio; Salcedo-Hernandez, Rubén; Bautista, Mayela; Jiménez, Beatriz; Ibarra, Jorge E.

    2003-01-01

    The endochitinase gene chiA74 from Bacillus thuringiensis serovar kenyae strain LBIT-82 was cloned in Escherichia coli DH5αF′. A sequence of 676 amino acids was deduced when the gene was completely sequenced. A molecular mass of 74 kDa was estimated for the preprotein, which includes a putative 4-kDa signal sequence located at the N terminus. The deduced amino acid sequence showed high degree of identity with other chitinases such as ChiB from Bacillus cereus (98%) and ChiA71 from Bacillus thuringiensis serovar pakistani (70%). Additionally, ChiA74 showed a modular structure comprised of three domains: a catalytic domain, a fibronectin-like domain, and a chitin-binding domain. All three domains showed conserved sequences when compared to other bacterial chitinase sequences. A ca. 70-kDa mature protein expressed by the cloned gene was detected in zymograms, comigrating with a chitinase produced by the LBIT-82 wild-type strain. ChiA74 is active within a wide pH range (4 to 9), although a bimodal activity was shown at pH 4.79 and 6.34. The optimal temperature was estimated at 57.2°C when tested at pH 6. The potential use of ChiA74 as a synergistic agent, along with the B. thuringiensis insecticidal Cry proteins, is discussed. PMID:12571025

  13. Experimental design and Bayesian networks for enhancement of delta-endotoxin production by Bacillus thuringiensis.

    PubMed

    Ennouri, Karim; Ayed, Rayda Ben; Hassen, Hanen Ben; Mazzarello, Maura; Ottaviani, Ennio

    2015-12-01

    Bacillus thuringiensis (Bt) is a Gram-positive bacterium. The entomopathogenic activity of Bt is related to the existence of the crystal consisting of protoxins, also called delta-endotoxins. In order to optimize and explain the production of delta-endotoxins of Bacillus thuringiensis kurstaki, we studied seven medium components: soybean meal, starch, KH₂PO₄, K₂HPO₄, FeSO₄, MnSO₄, and MgSO₄and their relationships with the concentration of delta-endotoxins using an experimental design (Plackett-Burman design) and Bayesian networks modelling. The effects of the ingredients of the culture medium on delta-endotoxins production were estimated. The developed model showed that different medium components are important for the Bacillus thuringiensis fermentation. The most important factors influenced the production of delta-endotoxins are FeSO₄, K2HPO₄, starch and soybean meal. Indeed, it was found that soybean meal, K₂HPO₄, KH₂PO₄and starch also showed positive effect on the delta-endotoxins production. However, FeSO4 and MnSO4 expressed opposite effect. The developed model, based on Bayesian techniques, can automatically learn emerging models in data to serve in the prediction of delta-endotoxins concentrations. The constructed model in the present study implies that experimental design (Plackett-Burman design) joined with Bayesian networks method could be used for identification of effect variables on delta-endotoxins variation. PMID:26689874

  14. Genomic characterization and comparison of seven Myoviridae bacteriophage infecting Bacillus thuringiensis.

    PubMed

    Sauder, Amber Brooke; Quinn, McKenzie Rea; Brouillette, Alexis; Caruso, Steven; Cresawn, Steven; Erill, Ivan; Lewis, Lynn; Loesser-Casey, Kathryn; Pate, Morgan; Scott, Crystal; Stockwell, Stephanie; Temple, Louise

    2016-02-01

    Bacillus thuringiensis Kurstaki, a bacterium that is a source of biopesticides and a safe simulant for pathogenic Bacillus species, was used to isolate seven unique bacteriophages. The phage genomes were sequenced and ranged in size from 158,100 to 163,019 bp encoding 290-299 genes, and the GC content of ~38% was similar to that of the host bacterium. All phages had terminal repeats 2-3 kb long. Three of the phages encoded tRNAs and three contained a self-splicing intron in the DNA polymerase gene. They were categorized as a single cluster (>60% nucleotide conservation) containing three subclusters (>80% nucleotide conservation), supported by genomic synteny and phylogenetic analysis. Considering the published genomes of phages that infect the genus Bacillus and noting the ability of many of the Bacillus cereus group phages to infect multiple species, a clustering system based on gene content is proposed. PMID:26773385

  15. 40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta...

  16. 40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta...

  17. 40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta...

  18. 40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta...

  19. The occurrence, biodiversity and toxicity of Bacillus thuringiensis strains isolated from the insect pest Lymantria dispar (Poland).

    PubMed

    Guz, Katarzyna; Bugla-Płoskońska, Gabriela; Doroszkiewicz, Włodzimierz

    2009-01-01

    The aim of this investigation was to survey the occurrence, biodiversity, and toxicity of Bacillus thuringiensis strains originating from dead caterpillars of the forest pest, Lymantria dispar (Lepidoptera). Morphological, biochemical, and microscopic identification of isolates from the insects showed the presence of five different Bacillus species, including 2% of B. thuringiensis. Based on the biochemical profiles, the B. thuringiensis were determined to be B. thuringiensis finitimus-like and B. thuringiensis alesti-like bacilli. Both produced spherical inclusions composed of three or five protoxins. The molecular weights of these proteins varied from 20 to ca. 64 kDa. Mixtures of spores/inclusions of the B. thuringiensis were tested for their toxicity against larvae of Drosophila melanogaster. The mortality levels of the larvae caused by these spores and crystalline inclusions varied from 5 to 15%. The lethal doses (LD50) of these isolates against D. melanogaster were 8.8 x 10(12) spores/ml for B. thuringiensis finitimus and 1.3 10(18) spores/ml for B. thuringiensis alesti. PMID:19824400

  20. Production and characterization of Bacillus thuringiensis Cry1Ac-resistant cotton bollworm Helicoverpa zea (Boddie).

    PubMed

    Anilkumar, Konasale J; Rodrigo-Simón, Ana; Ferré, Juan; Pusztai-Carey, Marianne; Sivasupramaniam, Sakuntala; Moar, William J

    2008-01-01

    Laboratory-selected Bacillus thuringiensis-resistant colonies are important tools for elucidating B. thuringiensis resistance mechanisms. However, cotton bollworm, Helicoverpa zea, a target pest of transgenic corn and cotton expressing B. thuringiensis Cry1Ac (Bt corn and cotton), has proven difficult to select for stable resistance. Two populations of H. zea (AR and MR), resistant to the B. thuringiensis protein found in all commercial Bt cotton varieties (Cry1Ac), were established by selection with Cry1Ac activated toxin (AR) or MVP II (MR). Cry1Ac toxin reflects the form ingested by H. zea when feeding on Bt cotton, whereas MVP II is a Cry1Ac formulation used for resistance selection and monitoring. The resistance ratio (RR) for AR exceeded 100-fold after 11 generations and has been maintained at this level for nine generations. This is the first report of stable Cry1Ac resistance in H. zea. MR crashed after 11 generations, reaching only an RR of 12. AR was only partially cross-resistant to MVP II, suggesting that MVP II does not have the same Cry1Ac selection pressure as Cry1Ac toxin against H. zea and that proteases may be involved with resistance. AR was highly cross-resistant to Cry1Ab toxin but only slightly cross-resistant to Cry1Ab expressing corn leaf powder. AR was not cross-resistant to Cry2Aa2, Cry2Ab2-expressing corn leaf powder, Vip3A, and cypermethrin. Toxin-binding assays showed no significant differences, indicating that resistance was not linked to a reduction in binding. These results aid in understanding why this pest has not evolved B. thuringiensis resistance, and highlight the need to choose carefully the form of B. thuringiensis protein used in experiments. PMID:18024681

  1. Molecular cloning of the 130-kilodalton mosquitocidal delta-endotoxin gene of Bacillus thuringiensis subsp. israelensis in Bacillus sphaericus.

    PubMed Central

    Trisrisook, M; Pantuwatana, S; Bhumiratana, A; Panbangred, W

    1990-01-01

    A 3.7-kilobase (kb) XbaI fragment harboring the cryIVB gene (L. Thorne, F. Garduno, T. Thompson, D. Decker, M. A. Zounes, M. Wild, A. M. Walfield, and T. J. Pollock, J. Bacteriol. 166:801-811, 1986) which encoded a 130-kilodalton (kDa) mosquitocidal toxin from a 110-kb plasmid of Bacillus thuringiensis subsp. israelensis 4Q2-72 was cloned into pUC12 and transformed into Escherichia coli. The clone with a recombinant plasmid (designated pBT8) was toxic to Aedes aegypti larvae. The fragment (3.7 kb) was ligated into pBC16 (tetracycline resistant [Tcr]) and transformed by the method of protoplast transformation into Bacillus sphaericus 1593 and 2362, which were highly toxic to Anopheles and Culex mosquito larvae but less toxic to Aedes larvae. After cell regeneration on regeneration medium, the Tcr plasmids from transformants (pBTC1) of both strains of B. sphaericus were prepared and analyzed. The 3.7-kb XbaI fragment from the B. thuringiensis subsp. israelensis plasmid was shown to be present by agarose gel electrophoresis and Southern blot hybridization. In addition, B. sphaericus transformants produced a 130-kDa mosquitocidal toxin which was detected by Western (immuno-) blot analysis with antibody prepared against B. thuringiensis subsp. israelensis 130-kDa mosquitocidal toxin. The 50% lethal concentrations of the transformants of strains 1593 and 2362 against A. aegypti larvae were 2.7 X 10(2) and 5.7 X 10(2) cells per ml, respectively. This level of toxicity was comparable to the 50% lethal concentration of B. thuringiensis subsp. israelensis but much higher than that of B. sphaericus 1593 and 2362 (4.7 X 10(4) cells per ml) against A. aegypti larvae.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:2200339

  2. 40 CFR 174.510 - Bacillus thuringiensis Cry1Ac protein in all plants; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Cry1Ac protein... Cry1Ac protein in all plants; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1Ac protein in all plants are exempt from the requirement of a tolerance when used as...

  3. 40 CFR 174.518 - Bacillus thuringiensis Cry3Bb1 protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacillus thuringiensis Cry3Bb1 protein... Cry3Bb1 protein in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry3Bb1 protein in corn are exempt from the requirement of a tolerance when used as...

  4. 40 CFR 174.510 - Bacillus thuringiensis Cry1Ac protein in all plants; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Cry1Ac protein... Cry1Ac protein in all plants; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1Ac protein in all plants are exempt from the requirement of a tolerance when used as...

  5. 40 CFR 174.518 - Bacillus thuringiensis Cry3Bb1 protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Cry3Bb1 protein... Cry3Bb1 protein in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry3Bb1 protein in corn are exempt from the requirement of a tolerance when used as...

  6. 40 CFR 174.511 - Bacillus thuringiensis Cry1Ab protein in all plants; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Cry1Ab protein... Cry1Ab protein in all plants; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1Ab protein in all plants are exempt from the requirement of a tolerance when used as...

  7. 40 CFR 174.518 - Bacillus thuringiensis Cry3Bb1 protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bacillus thuringiensis Cry3Bb1 protein... Cry3Bb1 protein in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry3Bb1 protein in corn are exempt from the requirement of a tolerance when used as...

  8. 40 CFR 174.510 - Bacillus thuringiensis Cry1Ac protein in all plants; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Cry1Ac protein... Cry1Ac protein in all plants; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1Ac protein in all plants are exempt from the requirement of a tolerance when used as...

  9. 40 CFR 174.518 - Bacillus thuringiensis Cry3Bb1 protein in corn; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Cry3Bb1 protein... Cry3Bb1 protein in corn; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry3Bb1 protein in corn are exempt from the requirement of a tolerance when used as...

  10. 40 CFR 174.511 - Bacillus thuringiensis Cry1Ab protein in all plants; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacillus thuringiensis Cry1Ab protein... Cry1Ab protein in all plants; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1Ab protein in all plants are exempt from the requirement of a tolerance when used as...

  11. 40 CFR 174.510 - Bacillus thuringiensis Cry1Ac protein in all plants; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacillus thuringiensis Cry1Ac protein... Cry1Ac protein in all plants; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1Ac protein in all plants are exempt from the requirement of a tolerance when used as...

  12. 40 CFR 174.511 - Bacillus thuringiensis Cry1Ab protein in all plants; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacillus thuringiensis Cry1Ab protein... Cry1Ab protein in all plants; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1Ab protein in all plants are exempt from the requirement of a tolerance when used as...

  13. 40 CFR 174.511 - Bacillus thuringiensis Cry1Ab protein in all plants; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacillus thuringiensis Cry1Ab protein... Cry1Ab protein in all plants; exemption from the requirement of a tolerance. Residues of Bacillus thuringiensis Cry1Ab protein in all plants are exempt from the requirement of a tolerance when used as...

  14. Dark fermentative bioconversion of glycerol to hydrogen by Bacillus thuringiensis.

    PubMed

    Kumar, Prasun; Sharma, Rishi; Ray, Subhasree; Mehariya, Sanjeet; Patel, Sanjay K S; Lee, Jung-Kul; Kalia, Vipin C

    2015-04-01

    Biodiesel manufacturing units discharge effluents rich in glycerol. The need is to convert crude glycerol (CG) into useful products such as hydrogen (H2). Under batch culture, Bacillusthuringiensis EGU45 adapted on pure glycerol (PG, 2% v/v) resulted in an H2 yield of 0.646 mol/mol glycerol consumed on minimal media (250 mL) supplemented with 1% ammonium nitrate at 37°C over 4 days. Here, H2 constituted 67% of the total biogas. Under continuous culture, at 2 days of hydraulic retention time, B. thuringiensis immobilized on ligno-cellulosic materials (banana leaves - BL, 10% v/v) resulted in a H2 yield of 0.386 mol/mol PG consumed. On CG, the maximal H2 yield of 0.393 mol/mol feed consumed was recorded. In brief, B. thuringiensis could transform CG, on limited resources - minimal medium with sodium nitrate, by immobilizing them on cheap and easily available biowaste, which makes it a suitable candidate for H2 production on a large scale. PMID:25686722

  15. Bacillus thuringiensis Metalloproteinase Bmp1 Functions as a Nematicidal Virulence Factor

    PubMed Central

    Luo, Xiaoxia; Chen, Ling; Huang, Qiong; Zheng, Jinshui; Zhou, Wei; Peng, Donghai; Ruan, Lifang

    2013-01-01

    Some Bacillus thuringiensis strains have high toxicity to nematodes. Nematicidal activity has been found in several families of crystal proteins, such as Cry5, Cry6, and Cry55. The B. thuringiensis strain YBT-1518 has three cry genes that have high nematicidal activity. The whole genome sequence of this strain contains multiple potential virulence factors. To evaluate the pathogenic potential of virulence factors, we focused on a metalloproteinase called Bmp1. It encompasses a consecutive N-terminal signal peptide, an FTP superfamily domain, an M4 neutral protease GluZincin superfamily, two Big-3 superfamily motifs, and a Gram-positive anchor superfamily motif as a C-terminal domain. Here, we showed that purified Bmp1 protein showed metalloproteinase activity and toxicity against Caenorhabditis elegans (the 50% lethal concentration is 610 ± 9.37 μg/ml). In addition, mixing Cry5Ba with Bmp1 protein enhanced the toxicity 7.9-fold (the expected toxicity of the two proteins calculated from their separate toxicities) against C. elegans. Confocal microscopic observation revealed that Bmp1 protein was detected from around the mouth and esophagus to the intestine. Striking microscopic images revealed that Bmp1 degrades intestine tissues, and the Cry5Ba causes intestinal shrinkage from the body wall. Thus, the B. thuringiensis Bmp1 metalloproteinase is a nematicidal virulence factor. These findings give a new insight into the relationship between B. thuringiensis and its host nematodes. PMID:23124228

  16. Activity of bacteriocins synthesized by Bacillus thuringiensis against Staphylococcus aureus isolates associated to bovine mastitis.

    PubMed

    Barboza-Corona, José Eleazar; de la Fuente-Salcido, Norma; Alva-Murillo, Nayeli; Ochoa-Zarzosa, Alejandra; López-Meza, Joel E

    2009-07-01

    Antimicrobial therapy is a useful tool to control bovine mastitis caused by Staphylococcus aureus, as consequence an increase in staphylococci resistant cases has been registered. Alternative strategies are desirable and bacteriocins represent attractive control agents to prevent bovine mastitis. The aim of this work was to evaluate the activity of five bacteriocins synthesized by Bacillus thuringiensis against S. aureus isolates associated to bovine mastitis. Fifty S. aureus isolates were recovered from milk composite samples of 26 Holstein lactating cows from one herd during September 2007 to February 2008 in México and susceptibility of those isolates to 12 antibiotics and 5 bacteriocins from B. thuringiensis was evaluated. S. aureus isolates were mainly resistant to penicillin (92%), dicloxacillin (86%), ampicillin (74%) and erythromycin (74%); whereas susceptibility to gentamicin, trimethoprim and tetracycline was detected at, respectively, 92%, 88%, and 72%. All S. aureus isolates showed susceptibility to the five bacteriocins synthesized by B. thuringiensis, mainly to morricin 269 and kurstacin 287 followed by kenyacin 404, entomocin 420 and tolworthcin 524. Our results showed that S. aureus isolates had differences in the antimicrobial resistance patterns and were susceptible to bacteriocins produced by B. thuringiensis, which could be useful as an alternative method to control bovine mastitis. PMID:19359107

  17. Binding of Bacillus thuringiensis proteins to a laboratory-selected line of Heliothis virescens.

    PubMed

    MacIntosh, S C; Stone, T B; Jokerst, R S; Fuchs, R L

    1991-10-15

    A laboratory-selected colony of Heliothis virescens displaying a 20- to 70-fold level of resistance to Bacillus thuringiensis proteins was evaluated to identify mechanism(s) of resistance. Brush-border membrane vesicles were isolated from larval midgut epithelium from the susceptible and resistant strains of H. virescens. Two B. thuringiensis proteins, CryIA(b) and CryIA(c), were iodinated and shown to specifically bind to brush-border membrane vesicles of both insect strains. Multiple changes in the receptor-binding parameters were seen in the resistant strain as compared with the susceptible strain. A 2- to 4-fold reduction in binding affinity was accompanied by a 4- to 6-fold increase in binding-site concentration for both proteins. Although these two B. thuringiensis proteins competed for the same high-affinity binding site, competition experiments revealed different receptor specificity toward these proteins in the resistant H. virescens line. The H. virescens strains were not sensitive to a coleopteran-active protein, CryIIIA, nor did these proteins compete with the CryIA proteins for binding. Complexity of the mechanism of resistance is consistent with the complex mode of action of B. thuringiensis proteins. PMID:1924353

  18. New variants of lepidoptericidal toxin genes encoding Bacillus thuringiensis Vip3Aa proteins.

    PubMed

    Sauka, Diego H; Rodriguez, Sonia E; Benintende, Graciela B

    2012-01-01

    Bacillus thuringiensis is an entomopathogenic bacterium characterized by producing parasporal proteinaceous insecticidal crystal inclusions during sporulation. Many strains are capable of also expressing other insecticidal proteins called Vip during the vegetative growing phase. Particularly, Vip3A proteins have activity against certain Lepidoptera species through a unique mechanism of action which emphasized their possible use in resistance management strategies against resistant pests. The aim of the work was to develop a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method that can distinguish between vip3A genes from B. thuringiensis strains. In addition, 4 novel vip3Aa genes were cloned and sequenced. The method was originally based on amplification of a single PCR amplicon and the use of 2 restriction enzymes with recognition sites that facilitate simultaneous detection. Subsequently, a third restriction enzyme was used to distinguish between vip3A variants. Thirteen vip3Aa genes were identified in strains belonging to 10 different B. thuringiensis serovars. Three intra-subclass variants of vip3Aa genes could be differentiated. The presented method can serve as an invaluable tool for the investigation of known and novel vip3A genes in B. thuringiensis strains. To the best of our knowledge, this is the first report where variants of a same subclass of insecticidal genes could be distinguished following PCR-RFLP. PMID:23307196

  19. Transduction of certain genes by an autonomously replicating Bacillus thuringiensis phage.

    PubMed Central

    Walter, T M; Aronson, A I

    1991-01-01

    A derivative of Bacillus thuringiensis subsp. kurstaki HD1 (HD1-9) released transducing phage (TP21) from late exponential cultures. Three of seven markers tested were transduced into Bacillus cereus, but only two of these (cysC and trpB/F) were transduced at a frequency of more than 100 times the reversion rates. A limited transduction capacity was given further support in that few chromosomal markers were carried in the HD1-9 lysate, as demonstrated by Southern hybridization. Restriction fragments from the phage DNA and from total B. thuringiensis DNA hybridized to an insertion sequence (IS231-like) probe, which may provide a region of homology for transduction. All of the B. cereus transductants contained the phage as a 44-kb plasmid, and each could transduce both the cys and trp genes to other B. cereus auxotrophs, albeit at lower frequencies than those for the B. thuringiensis transducing phage. In some cases, especially for cys, the transduced gene was integrated into the chromosome of the recipient, whereas the trp gene in many cases appeared to be lost with curing of the 44-kb plasmid. In addition, some B. cereus transductants lost prototrophy but retained a 44-kb plasmid, consistent with the presence of TP21 helper phage. These phage may mediate the subsequent transduction from B. cereus phototrophs. TP21 replicates as a plasmid and, at least under the conditions studied, selectively transfers markers to B. cereus. Images PMID:2059027

  20. Genes and environment interact to determine the fitness costs of resistance to Bacillus thuringiensis

    PubMed Central

    Raymond, Ben; Sayyed, Ali H; Wright, Denis J

    2005-01-01

    Genes which provide resistance to novel challenges such as pesticides, toxins or pathogens often impose fitness costs on individuals with a resistant phenotype. Studies of resistance to Bacillus thuringiensis and its insecticidal Cry toxins indicate that fitness costs may be variable and cryptic. Using two field populations (Karak and Serd4) of the diamondback moth, Plutella xylostella, we tested the hypothesis that the costs associated with resistance to the B. thuringiensis toxin Cry1Ac would be evident when insects were grown under poor environmental conditions, namely limited or poor quality resources. On a poor quality resource, a cultivar of Brassica oleracea var. capitata with varietal resistance to P. xylostella, only one resistant population, Karak, showed reduced fitness. Conversely, when we limited a high quality resource, Brassica pekinensis, by imposing larval competition, only resistant Serd4 insects had reduced survival at high larval densities. Furthermore, Cry1Ac resistance in Serd4 insects declined when reared at high larval densities while resistance at low densities fluctuated but did not decline significantly. These results confirm the hypothesis that resistance costs can appear under stressful conditions and demonstrate that the fitness cost of resistance to Bacillus thuringiensis can depend on the particular interaction between genes and the environment. PMID:16011928

  1. A purification and some properties of an insecticidal exotoxin from Bacillus thuringiensis Berliner

    PubMed Central

    Bond, R. P. M.; Boyce, C. B. C.; French, S. J.

    1969-01-01

    An insecticidal exotoxin from Bacillus thuringiensis var. thuringiensis (Berliner) has been purified. The efficiency of each stage of the purification has been ascertained and the yield of toxic material estimated by means of a quantitative bioassay. It is shown that the exotoxin is an adenine derivative substituted at position 9 and having a molecular weight of approximately 825. It can be dephosphorylated enzymically or chemically under conditions that define the exotoxin as a phosphomonoester. This results in loss of toxicity, both to insects and to mice. Spectroscopic and kinetic data are presented which suggest that a β-ribofuranosyl moiety may be attached to the adenine. Glucose and allomucic acid have been positively identified as hydrolysis fragments from the exotoxin. These results are discussed and compared with the results of others on similar (or possibly identical) compounds. PMID:5820635

  2. Neural networks applied to the prediction of fed-batch fermentation kinetics of Bacillus thuringiensis.

    PubMed

    Valdez-Castro, L; Baruch, I; Barrera-Cortés, J

    2003-01-01

    This paper proposes using a new recurrent neural network model (RNNM) to predict and control fed batch fermentations of Bacillus thuringiensis. The control variables are the limiting substrate and the feeding conditions. The multi-input multi-output RNNM proposed has twelve inputs, seven outputs, nineteen neurons in the hidden layer, and global and local feedbacks. The weight update learning algorithm designed is a version of the well known backpropagation through time algorithm directed to the RNNM learning. The error approximation for the last epoch of learning is 2% and the total learning time is 51 epochs, where the size of an epoch is 162 iterations. The RNNM generalization was carried out reproducing a B. thuringiensis fermentation not included in the learning process. It attains an error approximation of 1.8%. PMID:14505001

  3. Crystallization of parasporin-2, a Bacillus thuringiensis crystal protein with selective cytocidal activity against human cells.

    PubMed

    Akiba, Toshihiko; Abe, Yuichi; Kitada, Sakae; Kusaka, Yoshitomo; Ito, Akio; Ichimatsu, Tokio; Katayama, Hideki; Akao, Tetsuyuki; Higuchi, Kazuhiko; Mizuki, Eiichi; Ohba, Michio; Kanai, Ryuta; Harata, Kazuaki

    2004-12-01

    Bacillus thuringiensis is a valuable source of protein toxins that are specifically effective against certain insects and worms but harmless to mammals. In contrast, a protein toxin obtained from B. thuringiensis strain A1547, designated parasporin-2, is not insecticidal but has a strong cytocidal activity against human cells with markedly divergent target specificity. The 37 kDa inactive protein is proteolytically activated to a 30 kDa active form. The active form of the recombinant protein toxin was crystallized in the presence of ethylene glycol and polyethylene glycol 8000 at neutral pH. The crystals belong to the hexagonal space group P6(1) or P6(5), with unit-cell parameters a = b = 134.37, c = 121.24 A. Diffraction data from a native crystal were collected to 2.75 A resolution using a synchrotron-radiation source. PMID:15583389

  4. An ABC transporter from Bacillus thuringiensis is essential for beta-exotoxin I production.

    PubMed

    Espinasse, Sylvain; Gohar, Michel; Lereclus, Didier; Sanchis, Vincent

    2002-11-01

    beta-Exotoxin I is a nonspecific insecticidal metabolite secreted by some Bacillus thuringiensis strains. Several studies of B. thuringiensis strains that have lost the capacity to produce beta-exotoxin I have suggested that there is a strong correlation between high levels of beta-exotoxin I production and the ability to synthesize crystal proteins. In this study, we showed that a mutant strain, B. thuringiensis 407-1(Cry(-))(Pig(+)), with no crystal gene, produced considerable amounts of beta-exotoxin I together with a soluble brown melanin pigment. Therefore, beta-exotoxin I production can take place after a strain has lost the plasmids bearing the cry genes, which suggests that these curable plasmids probably contain determinants involved in the regulation of beta-exotoxin I production. Using a mini-Tn10 transposon, we constructed a library of strain 407-1(Cry(-))(Pig(+)) mutants. We screened for nonpigmented mutants with impaired beta-exotoxin I production and identified a genetic locus harboring two genes (berA and berB) essential for beta-exotoxin I production. The deduced amino acid sequence of the berA gene displayed significant similarity to the ATP-binding domains of the DRI (drug resistance and immunity) family of ATP-binding cassette (ABC) proteins involved in drug resistance and immunity to bacteriocins and lantibiotics. The berB gene encodes a protein with six putative transmembrane helices, which probably constitutes the integral membrane component of the transporter. The demonstration that berAB is required for beta-exotoxin I production and/or resistance in B. thuringiensis adds an adenine nucleotide analog to the wide range of substrates of the superfamily of ABC proteins. We suggest that berAB confers beta-exotoxin I immunity in B. thuringiensis, through active efflux of the molecule. PMID:12374817

  5. Constitutive activation of the midgut response to Bacillus thuringiensis in Bt-resistant Spodoptera exigua.

    PubMed

    Hernández-Martínez, Patricia; Navarro-Cerrillo, Gloria; Caccia, Silvia; de Maagd, Ruud A; Moar, William J; Ferré, Juan; Escriche, Baltasar; Herrero, Salvador

    2010-01-01

    Bacillus thuringiensis is the most effective microbial control agent for controlling numerous species from different insect orders. The main threat for the long term use of B. thuringiensis in pest control is the ability of insects to develop resistance. Thus, the identification of insect genes involved in conferring resistance is of paramount importance. A colony of Spodoptera exigua (Lepidoptera: Noctuidae) was selected for 15 years in the laboratory for resistance to Xentari™, a B. thuringiensis-based insecticide, reaching a final resistance level of greater than 1,000-fold. Around 600 midgut ESTs were analyzed by DNA-macroarray in order to find differences in midgut gene expression between susceptible and resistant insects. Among the differentially expressed genes, repat and arylphorin were identified and their increased expression was correlated with B. thuringiensis resistance. We also found overlap among genes that were constitutively over-expressed in resistant insects with genes that were up-regulated in susceptible insects after exposure to Xentari™, suggesting a permanent activation of the response to Xentari™ in resistant insects. Increased aminopeptidase activity in the lumen of resistant insects in the absence of exposure to Xentari™ corroborated the hypothesis of permanent activation of response genes. Increase in midgut proliferation has been proposed as a mechanism of response to pathogens in the adult from several insect species. Analysis of S. exigua larvae revealed that midgut proliferation was neither increased in resistant insects nor induced by exposure of susceptible larvae to Xentari™, suggesting that mechanisms other than midgut proliferation are involved in the response to B. thuringiensis by S. exigua larvae. PMID:20862260

  6. Constitutive Activation of the Midgut Response to Bacillus thuringiensis in Bt-Resistant Spodoptera exigua

    PubMed Central

    Hernández-Martínez, Patricia; Navarro-Cerrillo, Gloria; Caccia, Silvia; de Maagd, Ruud A.; Moar, William J.; Ferré, Juan; Escriche, Baltasar; Herrero, Salvador

    2010-01-01

    Bacillus thuringiensis is the most effective microbial control agent for controlling numerous species from different insect orders. The main threat for the long term use of B. thuringiensis in pest control is the ability of insects to develop resistance. Thus, the identification of insect genes involved in conferring resistance is of paramount importance. A colony of Spodoptera exigua (Lepidoptera: Noctuidae) was selected for 15 years in the laboratory for resistance to Xentari™, a B. thuringiensis-based insecticide, reaching a final resistance level of greater than 1,000-fold. Around 600 midgut ESTs were analyzed by DNA-macroarray in order to find differences in midgut gene expression between susceptible and resistant insects. Among the differentially expressed genes, repat and arylphorin were identified and their increased expression was correlated with B. thuringiensis resistance. We also found overlap among genes that were constitutively over-expressed in resistant insects with genes that were up-regulated in susceptible insects after exposure to Xentari™, suggesting a permanent activation of the response to Xentari™ in resistant insects. Increased aminopeptidase activity in the lumen of resistant insects in the absence of exposure to Xentari™ corroborated the hypothesis of permanent activation of response genes. Increase in midgut proliferation has been proposed as a mechanism of response to pathogens in the adult from several insect species. Analysis of S. exigua larvae revealed that midgut proliferation was neither increased in resistant insects nor induced by exposure of susceptible larvae to Xentari™, suggesting that mechanisms other than midgut proliferation are involved in the response to B. thuringiensis by S. exigua larvae. PMID:20862260

  7. Functional analysis of the sporulation-specific diadenylate cyclase CdaS in Bacillus thuringiensis

    PubMed Central

    Zheng, Cao; Ma, Yang; Wang, Xun; Xie, Yuqun; Ali, Maria K.; He, Jin

    2015-01-01

    Cyclic di-AMP (c-di-AMP) is a recently discovered bacterial secondary messenger molecule, which is associated with various physiological functions. In the genus Bacillus, the intracellular level and turnover of c-di-AMP are mainly regulated by three diadenylate cyclases (DACs), including DisA, CdaA and CdaS, and two c-di-AMP-specific phosphodiesterases (GdpP and PgpH). In this study, we demonstrated that CdaS protein from B. thuringiensis is a hexameric DAC protein that can convert ATP or ADP to c-di-AMP in vitro and the N-terminal YojJ domain is essential for the DAC activity. Based on the markerless gene knock-out method, we demonstrated that the transcription of cdaS was initiated by the sporulation-specific sigma factor σH and the deletion of cdaS significantly delayed sporulation and parasporal crystal formation. These findings contrast with similar experiments conducted using B. subtilis, wherein transcription of its cdaS was initiated by the sigma factor σG. Deletion of all the three DAC genes from a single strain was unsuccessful, suggesting that c-di-AMP is an indispensable molecule in B. thuringiensis. Phylogenetic analysis indicated increased diversity of CdaS in the B. cereus and B. subtilis Bacillus subgroups. In summary, this study identifies important aspects in the regulation of c-di-AMP in the genus Bacillus. PMID:26441857

  8. Functional analysis of the sporulation-specific diadenylate cyclase CdaS in Bacillus thuringiensis.

    PubMed

    Zheng, Cao; Ma, Yang; Wang, Xun; Xie, Yuqun; Ali, Maria K; He, Jin

    2015-01-01

    Cyclic di-AMP (c-di-AMP) is a recently discovered bacterial secondary messenger molecule, which is associated with various physiological functions. In the genus Bacillus, the intracellular level and turnover of c-di-AMP are mainly regulated by three diadenylate cyclases (DACs), including DisA, CdaA and CdaS, and two c-di-AMP-specific phosphodiesterases (GdpP and PgpH). In this study, we demonstrated that CdaS protein from B. thuringiensis is a hexameric DAC protein that can convert ATP or ADP to c-di-AMP in vitro and the N-terminal YojJ domain is essential for the DAC activity. Based on the markerless gene knock-out method, we demonstrated that the transcription of cdaS was initiated by the sporulation-specific sigma factor σ(H) and the deletion of cdaS significantly delayed sporulation and parasporal crystal formation. These findings contrast with similar experiments conducted using B. subtilis, wherein transcription of its cdaS was initiated by the sigma factor σ(G). Deletion of all the three DAC genes from a single strain was unsuccessful, suggesting that c-di-AMP is an indispensable molecule in B. thuringiensis. Phylogenetic analysis indicated increased diversity of CdaS in the B. cereus and B. subtilis Bacillus subgroups. In summary, this study identifies important aspects in the regulation of c-di-AMP in the genus Bacillus. PMID:26441857

  9. Resistance of Trichoplusia ni populations selected by Bacillus thuringiensis sprays to cotton plants expressing pyramided Bacillus thuringiensis toxins Cry1Ac and Cry2Ab.

    PubMed

    Kain, Wendy; Song, Xiaozhao; Janmaat, Alida F; Zhao, Jian-Zhou; Myers, Judith; Shelton, Anthony M; Wang, Ping

    2015-03-01

    Two populations of Trichoplusia ni that had developed resistance to Bacillus thuringiensis sprays (Bt sprays) in commercial greenhouse vegetable production were tested for resistance to Bt cotton (BollGard II) plants expressing pyramided Cry1Ac and Cry2Ab. The T. ni colonies resistant to Bacillus thuringiensis serovar kurstaki formulations were not only resistant to the Bt toxin Cry1Ac, as previously reported, but also had a high frequency of Cry2Ab-resistant alleles, exhibiting ca. 20% survival on BollGard II foliage. BollGard II-resistant T. ni strains were established by selection with BollGard II foliage to further remove Cry2Ab-sensitive alleles in the T. ni populations. The BollGard II-resistant strains showed incomplete resistance to BollGard II, with adjusted survival values of 0.50 to 0.78 after 7 days. The resistance to the dual-toxin cotton plants was conferred by two genetically independent resistance mechanisms: one to Cry1Ac and one to Cry2Ab. The 50% lethal concentration of Cry2Ab for the resistant strain was at least 1,467-fold that for the susceptible T. ni strain. The resistance to Cry2Ab in resistant T. ni was an autosomally inherited, incompletely recessive monogenic trait. Results from this study indicate that insect populations under selection by Bt sprays in agriculture can be resistant to multiple Bt toxins and may potentially confer resistance to multitoxin Bt crops. PMID:25480752

  10. Resistance of Trichoplusia ni Populations Selected by Bacillus thuringiensis Sprays to Cotton Plants Expressing Pyramided Bacillus thuringiensis Toxins Cry1Ac and Cry2Ab

    PubMed Central

    Kain, Wendy; Song, Xiaozhao; Janmaat, Alida F.; Zhao, Jian-Zhou; Myers, Judith; Shelton, Anthony M.

    2014-01-01

    Two populations of Trichoplusia ni that had developed resistance to Bacillus thuringiensis sprays (Bt sprays) in commercial greenhouse vegetable production were tested for resistance to Bt cotton (BollGard II) plants expressing pyramided Cry1Ac and Cry2Ab. The T. ni colonies resistant to Bacillus thuringiensis serovar kurstaki formulations were not only resistant to the Bt toxin Cry1Ac, as previously reported, but also had a high frequency of Cry2Ab-resistant alleles, exhibiting ca. 20% survival on BollGard II foliage. BollGard II-resistant T. ni strains were established by selection with BollGard II foliage to further remove Cry2Ab-sensitive alleles in the T. ni populations. The BollGard II-resistant strains showed incomplete resistance to BollGard II, with adjusted survival values of 0.50 to 0.78 after 7 days. The resistance to the dual-toxin cotton plants was conferred by two genetically independent resistance mechanisms: one to Cry1Ac and one to Cry2Ab. The 50% lethal concentration of Cry2Ab for the resistant strain was at least 1,467-fold that for the susceptible T. ni strain. The resistance to Cry2Ab in resistant T. ni was an autosomally inherited, incompletely recessive monogenic trait. Results from this study indicate that insect populations under selection by Bt sprays in agriculture can be resistant to multiple Bt toxins and may potentially confer resistance to multitoxin Bt crops. PMID:25480752