RESUMO
Proteins with molecular masses of 36 and 34 kDa (Bti36 and Bti34) were isolated from entomocidal crystals formed by Bacillus thuringiensis ssp. israelensis cells. The samples of Bti36 contained the admixture of a protein with a molecular mass of 33 kDa (Bti33), apparently a product of proteolysis of Bti36. These 3 proteins are significantly different in N-terminal sequences from known delta-endotoxins of B. thuringiensis and show antibacterial activity toward Micrococcus luteus. The combination of Bti36 and Bti33 also suppresses the growth of some other microorganisms including Streptomyces chrysomallus. The effects of the mixture of Bti36 and Bti33 on the M. luteus cell surface and on the surface of S. chrysomallus cells and exospores are similar, but they are different from the effect of endotoxin Cry11A on micrococcal cells.
Assuntos
Antibacterianos/farmacologia , Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/isolamento & purificação , Toxinas Bacterianas/química , Endotoxinas/química , Micrococcus luteus/efeitos dos fármacos , Streptomyces/efeitos dos fármacos , Aedes/efeitos dos fármacos , Animais , Antibacterianos/química , Bacillus thuringiensis/fisiologia , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/química , Proteínas de Bactérias/farmacologia , Proteínas Hemolisinas , Testes de Sensibilidade Microbiana , Micrococcus luteus/ultraestrutura , Microscopia Eletrônica de Varredura , Esporos Bacterianos/fisiologia , Esporos Bacterianos/ultraestrutura , Streptomyces/ultraestruturaRESUMO
Mosquitocidal endotoxins Cry4B, Cry11A, and CytA from Bacillus thuringiensis ssp. israelensis as well as the products of their limited proteolysis display antibacterial activity relative to Micrococcus luteus. The endotoxin Cry11A also induces the lysis of the micrococcus protoplasts. Potassium and sodium ions and N-acetylgalactosamine increased the antibacterial effect of Cry11A, whereas glucose and N-acetylglucosamine inhibited it. The endotoxin Cry11A displays the antibacterial effect on some other microorganisms.
