RESUMO
In order to investigate the binding ability of Lactobacillus strains to Benzo(a)pyrene (BaP), 15 strains were analysed. L. plantarum CICC 22135 and L. pentosus CICC 23163 exhibited high efficiency in removing BaP from aqueous medium; the binding rates were 66.76% and 64.31%, respectively. This process was affected by temperature, incubation time and pH, and cell viability was not necessary for the binding ability. Additionally, both strains, especially strain CICC 23163 showed high specificity in binding BaP. The cell-BaP complexes were stable in aqueous medium. The mechanism of binding was investigated by examining the binding ability of different components of the microorganism cells. The results revealed that peptidoglycans played an important role in binding BaP and its structural integrity was required. Consequently, we proposed that the mechanism of this process was a physisorption and peptidoglycan was the main binding site. These two strains may be used for dietary detoxification in human diet and animal feed.
Assuntos
Proteínas de Bactérias/metabolismo , Benzo(a)pireno/metabolismo , Carcinógenos/metabolismo , Contaminação de Alimentos/prevenção & controle , Lactobacillus/metabolismo , Peptidoglicano/metabolismo , Adsorção/efeitos da radiação , Proteínas de Bactérias/análise , Proteínas de Bactérias/química , Proteínas de Bactérias/efeitos da radiação , Benzo(a)pireno/toxicidade , Sítios de Ligação/efeitos da radiação , Carcinógenos/toxicidade , Parede Celular/química , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Lactobacillus/efeitos dos fármacos , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/efeitos da radiação , Lactobacillus plantarum/efeitos dos fármacos , Lactobacillus plantarum/crescimento & desenvolvimento , Lactobacillus plantarum/metabolismo , Lactobacillus plantarum/efeitos da radiação , Glicoproteínas de Membrana/análise , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/metabolismo , Viabilidade Microbiana , Peptidoglicano/análise , Peptidoglicano/química , Peptidoglicano/efeitos da radiação , Estabilidade Proteica/efeitos da radiação , Sonicação , Esferoplastos/química , Esferoplastos/efeitos dos fármacos , Esferoplastos/metabolismo , Propriedades de Superfície/efeitos da radiação , Ácidos Teicoicos/análise , Ácidos Teicoicos/metabolismo , TemperaturaRESUMO
This present study was carried out to evaluate the effects of gamma irradiation on the fatty acids (FA) and mureins composition of two different radiotolerant bacteria. Bacillus cereus LSPQ 2872 and Salmonella Typhi ATCC 19430 were used for this study. The bacterial strains were treated with a sublethal radiation dose of 1kGy to cause a cellular damage. Gas chromatography (GC) and high performance liquid chromatography (HPLC) analysis were performed to demonstrate respectively the modification of the FA composition and the changes in muropeptide profile. Results obtained show, for both bacteria, that this treatment had a significant effect (P< or =0.05) on the FA content with an increase of unsaturated FA percentage. Substantial changes were also noticed for the relative percentage and the number of the muropeptides. This study represents one of the few to demonstrate the modifications on bacterial membrane as a cellular response to survive the ionising radiation stress.
Assuntos
Bacillus cereus/efeitos da radiação , Membrana Celular/efeitos da radiação , Irradiação de Alimentos , Raios gama , Salmonella typhi/efeitos da radiação , Membrana Celular/química , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Relação Dose-Resposta à Radiação , Ácidos Graxos/análise , Ácidos Graxos/efeitos da radiação , Peptidoglicano/análise , Peptidoglicano/efeitos da radiaçãoRESUMO
AIMS: The aim of this study was to evaluate the effect of gamma-irradiation on the fatty acids (FA) and muropeptides content of two strains of an Enterobacteriacea: Pantoea agglomerans. METHODS AND RESULTS: Pantoea agglomerans strains ATCC 49174 and RL1 isolated from irradiated carrots were used for this study. Radiation treatments (1 and 3.5 kGy) were performed to study the radiotolerance. Total lipids were obtained by multiple extractions using methanol/chloroform (2 : 1) and were quantified by GC. Muropeptides were purified by successive enzymatic digestions and analysed using a reverse phase C(18) column in high performance liquid chromatography. A significant (P Assuntos
Parede Celular/efeitos da radiação
, Irradiação de Alimentos/métodos
, Raios gama
, Pantoea/efeitos da radiação
, Peptidoglicano/efeitos da radiação
, Parede Celular/química
, Cromatografia Líquida de Alta Pressão
, Daucus carota/microbiologia
, Ácidos Graxos/análise
, Ácidos Graxos/efeitos da radiação
, Peptidoglicano/análise