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Culturing and Maintaining Clostridium difficile in an Anaerobic Environment
Published on: September 15, 2013
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El clivado autocatalítico de la toxina B de Clostridium difficile es el resultado de una
Jessica Reineke1, Stefan Tenzer, Maja Rupnik
1Johannes-Gutenberg Universität Mainz, Institut für medizinische Mikrobiologie and Hygiene, Hochhaus am Augustusplatz, 55131 Mainz, Germany.
Nature
|March 6, 2007
Resumen
Las toxinas de Clostridium difficile utilizan fosfatos de inositol del huésped para la auto-escisión y la entrada en las células. Este mecanismo de activación autoproteolítica es crucial para la virulencia bacteriana y ofrece nuevos objetivos terapéuticos.
Área de la Ciencia:
- Microbiología Microbiología.
- Biología celular Biología celular.
- La bioquímica es la bioquímica.
Sus antecedentes:
- El Clostridium difficile causa infecciones adquiridas en el hospital como la diarrea y la colitis.
- Sus principales factores de virulencia son las grandes citotoxinas clostridiales A y B.
- Las teorías anteriores sugirieron que los factores citosólicos del huésped dividen la toxina B durante la entrada celular.
Objetivo del estudio:
- Para investigar el mecanismo de la gran activación de la citotoxina clostridial.
- Para identificar los factores del huésped involucrados en la escisión de la toxina B.
- Para aclarar el papel de los fosfatos de inositol en la activación de toxinas.
Principales métodos:
- Se utilizó un inhibidor de la proteasa aspartato covalente, 1,2-epoxi-3-(p-nitrofenóxi) propano.
- Función evaluada de la toxina B en células de cultivo.
- Identificó el sitio de la proteasa catalíticamente activa.
Principales resultados:
- La toxina B y otras grandes citotoxinas clostridiales se someten a una escisión autocatalítica.
- Este proceso es dependiente de los cofactores citosólicos inositol fosfato del huésped.
- El inhibidor de la proteasa bloqueó la actividad de la toxina B y ayudó a identificar su sitio activo.
Conclusiones:
- La activación de la toxina bacteriana a través de la autoproteólisis inducida utilizando señales eucariotas es un hallazgo novedoso.
- La autoproteólisis dependiente del fosfato de inositol es esencial para entregar el dominio tóxico en las células huésped.
- Se propuso un modelo integrado para la absorción y activación de la toxina B.
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