Publication: Caracterización bioquímica y genética de la infantaricina A: una nueva bacteriocina antineumocócica producida por la cepa de origen lácteo "Streptococcus infantarius" subesp. "infantarius" LP90
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2018-11-12
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Universidad Complutense de Madrid
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Abstract
En este trabajo se ha investigado la utilidad del empleo de bacterias lácticas, principalmente de origen alimentario, y/o sus bacteriocinas como estrategia alternativa o complementaria a los antibióticos para el control de las infecciones causadas por Streptococcus pneumoniae en humanos, empleando para ello diversas técnicas microbiológicas, bioquímicas y genéticas. En el Capítulo III se describe la evaluación de la actividad antimicrobiana de 38 BAL bacteriocinogénicas frente a cepas clínicas de S. pneumoniae de diversos serotipos y patrones de susceptibilidad a los antibióticos más empleados en medicina humana utilizando ensayos de antagonismo microbiano (i. e., inhibición por siembra en picadura [ISP], técnica de difusión en agar [TDA] y ensayo en placas microtituladoras [EPM]). Streptococcus infantarius subesp. infantarius LP90, una cepa aislada de leche de búfala de Venezuela, destacó por su amplio y potente espectro de acción frente a S. pneumoniae, por lo que fue seleccionada para su posterior caracterización. La purificación mediante un protocolo multicromatográfico de las bacteriocinas producidas por S. infantarius LP90, así como su análisis mediante espectrometría de masas MALDI-TOF, permitió determinar que la actividad antineumocócica de esta cepa es debida a la producción de, al menos, una nueva bacteriocina con una masa molecular de 3.963 Da a la que se denominó infantaricina A (InfA). La comparación de la secuencia aminoacídica de la región N-terminal de 19 aminoácidos de InfA, obtenida mediante degradación N-terminal de Edman, con las de otras proteínas depositadas en la base de datos Genbank reveló una elevada homología con una hipotética proteína de S. infantarius ATCCBAA-102...
This research work focused on the evaluation of the potential application of lactic acid bacteria, mainly of food origin, and/or their bacteriocins as an alternative or complementary strategy to antibiotics for the control of infections caused by Streptococcus pneumoniae in humans by using microbiological, biochemical and genetic techniques. Chapter III describes the evaluation of the antimicrobial activity of 38 bacteriocinogenic LAB against clinical isolates of S. pneumoniae, with different serotypes and antimicrobial resistance profiles to the antibiotics most commonly used in human medicine, by using microbial antagonism assays (i. e., stab-onagar test [SOAT], agar well-diffusion test [ADT] and microtiter plate assay [MPA]). Streptococcus infantarius subsp. infantarius LP90, a strain isolated from Venezuelan waterbuffalo milk, was selected for further characterization due to its broad and strong antimicrobial spectrum against S. pneumoniae. Purification of the bacteriocins produced by S. infantarius LP90 by a multi-chromatographic procedure, as well as MALDI-TOF mass spectrometry analysis, allowed to determine that the anti-pneumococcal activity of this strain is due to the production of, at least, a novel bacteriocin with a molecular mass of 3,963 Da, which was termed infantaricin A (InfA). Comparison of the 19 N-terminal amino acids of InfA, obtained by N-terminal Edman-degradation, with those present at Genbank database revealed a high homology to an hypothetical protein of S. infantarius ATCCBAA-102...
This research work focused on the evaluation of the potential application of lactic acid bacteria, mainly of food origin, and/or their bacteriocins as an alternative or complementary strategy to antibiotics for the control of infections caused by Streptococcus pneumoniae in humans by using microbiological, biochemical and genetic techniques. Chapter III describes the evaluation of the antimicrobial activity of 38 bacteriocinogenic LAB against clinical isolates of S. pneumoniae, with different serotypes and antimicrobial resistance profiles to the antibiotics most commonly used in human medicine, by using microbial antagonism assays (i. e., stab-onagar test [SOAT], agar well-diffusion test [ADT] and microtiter plate assay [MPA]). Streptococcus infantarius subsp. infantarius LP90, a strain isolated from Venezuelan waterbuffalo milk, was selected for further characterization due to its broad and strong antimicrobial spectrum against S. pneumoniae. Purification of the bacteriocins produced by S. infantarius LP90 by a multi-chromatographic procedure, as well as MALDI-TOF mass spectrometry analysis, allowed to determine that the anti-pneumococcal activity of this strain is due to the production of, at least, a novel bacteriocin with a molecular mass of 3,963 Da, which was termed infantaricin A (InfA). Comparison of the 19 N-terminal amino acids of InfA, obtained by N-terminal Edman-degradation, with those present at Genbank database revealed a high homology to an hypothetical protein of S. infantarius ATCCBAA-102...
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Tesis de la Universidad Complutense de Madrid, Facultad de Veterinaria, Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, leída el 27/01/2016