Caracterización bioquímica y genética de la infantaricina AUna nueva bacteriocina antineumocócica producida por la cepa de origen lácteo "streptococcus infantarius" subesp. infantarius LP90

  1. CAMPANERO PINTADO, CRISTINA
Supervised by:
  1. Pablo E. Hernández Cruza Director
  2. C. Herranz Sorribes Director
  3. L. M. Cintas Izarra Director

Defence university: Universidad Complutense de Madrid

Fecha de defensa: 27 January 2016

Committee:
  1. Paloma Morales Gómez Chair
  2. Bélen Orgaz Martin Secretary
  3. Gilberto Paulo Peixoto Igrejas Committee member
  4. Rosa del Campo Moreno Committee member
  5. Antonio Basanta Díaz Committee member
Department:
  1. Nutrición y Ciencia de los Alimentos

Type: Thesis

Teseo: 144582 DIALNET lock_openDocta Complutense editor

Abstract

This research work focused on the evaluation of the potential application of lactic acidbacteria, mainly of food origin, and/or their bacteriocins as an alternative or complementarystrategy to antibiotics for the control of infections caused by Streptococcus pneumoniae inhumans by using microbiological, biochemical and genetic techniques. Chapter III describes theevaluation of the antimicrobial activity of 38 bacteriocinogenic LAB against clinical isolates ofS. pneumoniae, with different serotypes and antimicrobial resistance profiles to the antibioticsmost commonly used in human medicine, by using microbial antagonism assays (i. e., stab-onagartest [SOAT], agar well-diffusion test [ADT] and microtiter plate assay [MPA]).Streptococcus infantarius subsp. infantarius LP90, a strain isolated from Venezuelan waterbuffalomilk, was selected for further characterization due to its broad and strong antimicrobialspectrum against S. pneumoniae. Purification of the bacteriocins produced by S. infantariusLP90 by a multi-chromatographic procedure, as well as MALDI-TOF mass spectrometryanalysis, allowed to determine that the anti-pneumococcal activity of this strain is due to theproduction of, at least, a novel bacteriocin with a molecular mass of 3,963 Da, which wastermed infantaricin A (InfA). Comparison of the 19 N-terminal amino acids of InfA, obtainedby N-terminal Edman-degradation, with those present at Genbank database revealed a highhomology to an hypothetical protein of S. infantarius ATCCBAA-102...