title: Food safety assessment of Cry8Ka5 mutant protein using Cry1Ac as a control Bt protein.
abstract: 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.
authors.affiliation: Graduate Program in Biochemistry, Federal University of Ceará, 60440-900, Fortaleza, CE, Brazil.
authors.forename: Davi Felipe
authors.initials: DF
authors.lastname: Farias
authors.affiliation: Graduate Program in Biochemistry, Federal University of Ceará, 60440-900, Fortaleza, CE, Brazil.
authors.forename: Martônio Ponte
authors.initials: MP
authors.lastname: Viana
authors.affiliation: Graduate Program in Bioprocess Engineering and Biotechnology, Federal University of Paraná, P.O. Box 19011, 81531-98, Curitiba, PR, Brazil; Parque Estação Biológica, National Center of Genetic Resources (Embrapa-Cenargen), PqEB - Av. W5 Norte (final), P.O. Box 02372, 70770-917, Brasília, DF, Brazil.
authors.forename: Gustavo Ramos
authors.initials: GR
authors.lastname: Oliveira
authors.affiliation: Parque Estação Biológica, National Center of Genetic Resources (Embrapa-Cenargen), PqEB - Av. W5 Norte (final), P.O. Box 02372, 70770-917, Brasília, DF, Brazil.
authors.forename: Vanessa Olinto
authors.initials: VO
authors.lastname: Santos
authors.affiliation: Graduate Program in Biochemistry, Federal University of Ceará, 60440-900, Fortaleza, CE, Brazil.
authors.forename: Clidia Eduarda Moreira
authors.initials: CEM
authors.lastname: Pinto
authors.affiliation: Graduate Program in Biotechnology, Ceará State University, 60740-903, Fortaleza, CE, Brazil.
authors.forename: Daniel Araújo
authors.initials: DA
authors.lastname: Viana
authors.affiliation: Graduate Program in Biochemistry, Federal University of Ceará, 60440-900, Fortaleza, CE, Brazil.
authors.forename: Ilka Maria
authors.initials: IM
authors.lastname: Vasconcelos
authors.affiliation: Parque Estação Biológica, National Center of Genetic Resources (Embrapa-Cenargen), PqEB - Av. W5 Norte (final), P.O. Box 02372, 70770-917, Brasília, DF, Brazil; Graduate Program in Gemonics Sciences and Biotechnology, Catholic University of Brasília, SGAN Quadra 916, Módulo B, W5 Norte, Asa Norte, 70790-160 Brasília, DF, Brazil.
authors.forename: Maria Fátima
authors.initials: MF
authors.lastname: Grossi-de-Sa
authors.affiliation: Graduate Program in Biochemistry, Federal University of Ceará, 60440-900, Fortaleza, CE, Brazil. Electronic address: aurano@ufc.br.
authors.forename: Ana Fontenele Urano
authors.initials: AFU
authors.lastname: Carvalho
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000595:Amino Acid Sequence; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001413:Bacillus thuringiensis / Q000235:genetics; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000009:adverse effects* / Q000235:genetics; D001772:Blood Cell Count; D002784:Cholesterol / Q000097:blood; D019295:Computational Biology; D003404:Creatinine / Q000097:blood; D004731:Endotoxins / Q000009:adverse effects* / Q000235:genetics; D005260:Female; D059022:Food Safety; D006460:Hemolysin Proteins / Q000009:adverse effects* / Q000235:genetics; D007313:Insecta; D007306:Insecticides; D007928:Lethal Dose 50; D051379:Mice; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000009:adverse effects* / Q000235:genetics; D009929:Organ Size / Q000187:drug effects; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified / Q000235:genetics; D023382:Toxicity Tests, Acute / Q000379:methods*; D014280:Triglycerides / Q000097:blood; D014508:Urea / Q000097:blood
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; D050505:Mutant Proteins; D014280:Triglycerides; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D014508:Urea; D002784:Cholesterol; D003404:Creatinine; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase
keywords: Bacillus thuringiensis; GMO; Risk assessment; Two-tiered approach; δ-endotoxin