Bacillus Thuringiensis Biotechnology

ISBN-13: 9789400799509 / Angielski / Miękka / 2014 / 392 str.

Estibaliz Sansinenea

Opis

Bacillus thuringiensis (Bt) has been used as a biopesticide in agriculture, forestry and mosquito control because of its advantages of specific toxicity against target insects, lack of polluting residues and safety to non-target organisms. The insecticidal properties of this bacterium are due to insecticidal proteins produced during sporulation. Despite these ecological benefits, the use of Bt biopesticides has lagged behind the synthetic chemicals. Genetic improvement of Bt natural strains, in particular Bt recombination, offers a promising means of improving efficacy and cost-effectiveness of Bt-based bioinsecticide products to develop new biotechnological applications. On the other hand, the different Bacillus species have important biotechnological applications; one of them is carried out by producing secondary metabolites, which are the study object of natural product chemistry. The amazing structural variability of these compounds has attracted the curiosity of chemists and the biological activities possessed by natural products have inspired the pharmaceutical industry to search for lead structures in microbial extracts. Screening of microbial extracts reveals the large structural diversity of natural compounds with broad biological activities, such as antimicrobial, antiviral, immunosuppressive, and antitumor activities that enable the bacterium to survive in its natural environment. These findings widen the target range of Bacillus spp., in special B. thuringiensis, besides insecticidal activity and help people to better understand its role in soil ecosystem.

Spis treści

Index Of Contributors.- Preface.- PART I BACILLUS THURINGIENSIS: AN ENVIRONMENTALLY SAFETY ALTERNATIVE.- 1 Discovery and description of Bacillus thuringiensis.- 1 .1 Introduction.-  1.2 A brief History and Discovery of Bacillus thuringiensis.- 1.3 A Description of B. thuringiensis.- 1.4 Conclusions.- References.- 2 Bacillus thuringiensis applications in agriculture.- 2.1 Introduction.- 2.2 Methods of application of Bt and its products in agriculture.- 2.3 Advantages of using Bt products over chemical agents in agricultural  practices.- 2.4 Threat to continuous use of Bt as biological control agent.- 2.5 Strategies to ensure continuing use of Bt and its products in agriculture.- References.- 3 Risk Assessment of Bt Transgenic Crops.- 3.1 Introduction.- 3.2 Perceived risks with Bt transgenic crops.- 3.3 Risk analysis of Bt transgenic crops.- 3.4 Oversight of Bt Transgenic crops.- 3.5 Conclusion and Future Prospects.- References.- 4 Use and efficacy of Bt compared to less environmentally safe alternatives .- 4.1 Biopesticide Classification.- 4.2 Biopesticide Market Survey.- 4.3 Use of Bt in IPM.- 4.4 Use and Efficacy of Bt.- References.-  5 Protein Engineering of Bacillus thuringiensis δ-Endotoxins .- 5.1 Introduction.- 5.2 Protein Engineering of Bt δ-endotoxins.- 5.3 Conclusions.- 5.4 Perspectives.- References.- PART II  GENETICS OF BACILLUS THURINGIENSIS.-  6 Evolution of the Bacillus cereus group.- 6.1 The Bacillus cereus group.- 6.2 B. cereus group phylogeny.- 6.3 Bacillus cereus group genome sequencing.- 6.4 Bacillus cereus group bacteria – pathogens and symbionts.- 6.5 What distinguishes the species in the B. cereus group?.- 6.6 Importance of plasmids to B. cereus group biology.- References.- 7 Bacillus thuringiensis genetics and phages - from transduction and sequencing to recombineering .- 7.1 Introduction: a dramatic story of the Bacillus cereus genetics.- 7.2 Phage-mediated gene transduction.- 7.3 Phage-mediated gene transduction in the B. cereus group.- 7.4 Recombineering perspectives for the B. cereus group.- References.-  8 Conjugation in Bacillus thuringiensis: insights into the plasmids exchange process.- 8.1 Introduction.- 8.2  Conjugation as a tool to understand the ecology of B. cereus group.- 8.3 Conclusion and Perspectives.- References.- 9  Shuttle vectors of Bacillus thuringiensis .- 9.1 Introduction.- 9.2 Plasmids in Bacillus thuringiensis.- 9.3 Shuttle vectors of Bacillus thuringiensis.- 9.4 Transformation of Bacillus thuringiensis.- References.-  10 Construction and application in plasmid vectors of Bacillus cereus group .- 10.1 Introduction.- 10.2 Shuttle plasmid vectors in the B. cereus group.- 10.3 Integration vectors in the B. cereus group.- 10.4 Resolution vectors in the B. cereus group.- 10.5 High-effective expression vectors in the B. cereus group.- 10.6 Conclusion.- References.-  11 Recombination in Bacillus thuringiensis.- 11.1 Introduction.- 11.2 Site Specific Recombination in B. thuringiensis.- 11.3 Homologous Recombination in B. thuringiensis.- 11.4 Conclusion.- References.-  12 Genetic improvement of Bt strains and development of novel biopesticides.- 12.1 Introduction.- 12.2 Discovery of new Bt strains harbouring novel cry genes.- 12.3 Engineering of novel Cry proteins.- 12.4 Construction of new Bt strains by conjugation.- 12.5 Expression of Bt cry genes in heterologous microbial hosts.- 12.6 Development of recombinant Bt strains.- 12.7 Development of asporogenic Bt strains.- 12.8 Concluding remarks.- References.- PART III BT AS BIOPESTICIDE: APPLICATIONS IN BIOTECHNOLOGY.-  13 Genetically Modified Bacillus thuringiensis Biopesticides .- 13.1 Introduction.- 13.2 Strategies for constructing genetically modified Bt strains for engineered biopesticide development.- 13.3 Bt engineered strains with high toxicity or broader insecticidal spectrum.- 13.4 Multifunctional Bt engineered strains.- 13.5 Genetically modified Bt strains with delayed pest resistance.- References.- 14 Bacillus thuringiensis Recombinant Insecticidal Protein Production.- 14.1 Introduction.- 14.2 Pesticidal Protein Expression in Gram Negative Hosts.- 14.3 Pesticidal Protein Expression in B. thuringiensis.- 14.4 Bacterial expression applications summary.- 14.5 Expression in Transgenic Plants.- 14.6 Plant Expression Summary.- 14.7 Conclusion.- Bibliography.- 15 Bt crops: past and future .- 15.1 Introduction.- 15.2 Developments conducive to Bt crops.- 15.3 Commercialization and performance of “first generation” Bt crops.- 15.4 Risks associated with the use of Bt crops.- 15.5 “Second” and “third” generation Bt crops.- 15.6 Conclusions and future prospects.- References.- 16 A Review of the Food Safety of Bt Crops.- 16.1 Background.- 16.2 Regulatory guidance for the safety assessment of Cry proteins.- 16.3 The Species-specific acute mode of action of Cry proteins.- 16.4 Potential digestibility of Cry proteins.- 16.5 Toxicology testing of Cry proteins.- 16.6 Assessment of food processing on Cry protein biological activity.- 16.7 Human dietary exposure assessment for Cry proteins in Bt crops.- 16.8 Toxicology feeding studies in rodents fed Bt crops.- 16.9 Food and Feed Safety Benefits of Bt Crops.- 16.10 Conclusions.- References.- PART IV OTHER BACILLUS SPECIES IN BIOTECHNOLOGY.- 17 The most important Bacillus species in biotechnology.- 17.1 Introduction.- 17.2 Most important biotechnological applications of Bacillus species.- 17.3 Conclusions and perspectives.- References.-  18 Secondary metabolites of Bacillus: potentials in biotechnology.- 18.1 Introduction.- 18.2 The most important secondary metabolites of Bacillus species.- 18.3 Other metabolites and activities of Bacillus species.- 18.4 Secondary metabolites from marine Bacilli.- 18.5 Safety evaluation and risk assessment.- 18.6 Conclusion and perspectives.- References.- 19 Future challenges and prospects of Bacillus thuringiensis.- 19.1 Introduction.- 19.2 Chitinases of B. thuringiensis in environment and food industry.- 19.3 Bacteriocins of Bacillus thuringiensis.- References.