RESUMO

Cry8Ka5 is a mutant protein from Bacillus thuringiensis (Bt) that has been proposed for developing transgenic plants due to promising activity against coleopterans, like Anthonomus grandis (the major pest of Brazilian cotton culture). Thus, an early food safety assessment of Cry8Ka5 protein could provide valuable information to support its use as a harmless biotechnological tool. This study aimed to evaluate the food safety of Cry8Ka5 protein following the two-tiered approach, based on weights of evidence, proposed by ILSI. Cry1Ac protein was used as a control Bt protein. The history of safe use revealed no convincing hazard reports for Bt pesticides and three-domain Cry proteins. The bioinformatics analysis with the primary amino acids sequence of Cry8Ka5 showed no similarity to any known toxic, antinutritional or allergenic proteins. The mode of action of Cry proteins is well understood and their fine specificity is restricted to insects. Cry8Ka5 and Cry1Ac proteins were rapidly degraded in simulated gastric fluid, but were resistant to simulated intestinal fluid and heat treatment. The LD50 for Cry8Ka5 and Cry1Ac was >5000 mg/kg body weight when administered by gavage in mice. Thus, no expected relevant risks are associated with the consumption of Cry8Ka5 protein.

Assuntos

Proteínas de Bactérias/efeitos adversos , Endotoxinas/efeitos adversos , Inocuidade dos Alimentos , Proteínas Hemolisinas/efeitos adversos , Proteínas Mutantes/efeitos adversos , Testes de Toxicidade Aguda/métodos , Alanina Transaminase/sangue , Fosfatase Alcalina/sangue , Sequência de Aminoácidos , Animais , Aspartato Aminotransferases/sangue , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Contagem de Células Sanguíneas , Colesterol/sangue , Biologia Computacional , Creatinina/sangue , Endotoxinas/genética , Feminino , Proteínas Hemolisinas/genética , Insetos , Inseticidas , Dose Letal Mediana , Camundongos , Dados de Sequência Molecular , Proteínas Mutantes/genética , Tamanho do Órgão/efeitos dos fármacos , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/genética , Triglicerídeos/sangue , Ureia/sangue