Caracterização de bacteriocina sintetizada por amostra de Shigella sonnei isolada de criança com diarreia aguda

Detalhes bibliográficos
Ano de defesa: 2013
Autor(a) principal: Patrícia Luciana de Oliveira
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Minas Gerais
UFMG
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://hdl.handle.net/1843/BUBD-9BQFEM
Resumo: Shigella is one of the most important bacterial agents of acute diarrhea.Bacteriocins are antimicrobial proteinaceous substances synthesized by a huge variety of bacteria including Shigella that seem to contribute to the virulence of the organism. We addressed the characterization of a bacteriocin produced by a Shigella sonnei isolate (SsP). The activity spectrum of SsP and the distribution of the characteristic ability to synthesize bacteriocins among SsP were evaluated. MIC and MBC of the intracellular fraction precipitated with 75% (NH4)2SO4) were also determined. Molecular mass of bacteriocin(s) found in C75 was estimated by SDS-PAGE. C75 was submitted to sequential steps of chromatography and partially purified fractions were evaluated by mass spectrometry (MS). A narrow activity spectrum against taxonomically related organisms both enteropathogens and members of the intestinal microbiota was observed. The ability to express antagonism was homogeneously distributed among SsP population. CIM and CBM values as well as the short period required to eliminate the indicator strain indicated that C75 is bactericidal. Two protein bands of 57 and 66 kDa showed activity. Taken together this result, the diversity of inhibition halos sizes, and the detection of several active fractions in every purification step suggest that SsP synthesizes more than one bacteriocin. The partial purification of the bacteriocin(s) found in C75 was achieved as demonstrated by MS. Sequences obtained did not match any bacteriocin stored in the searched databases.