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Electrochemical Detection of Deuterium Kinetic Isotope Effect on Extracellular Electron Transport in Shewanella oneidensis MR-1
Published on: April 16, 2018
Un papel para las quinonas excretadas en la transferencia extracelular de electrones
1Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA. dkn@gps.caltech.edu
Nature
|May 16, 2000
Resumen
Las bacterias pueden usar minerales para la respiración, pero no está claro cómo transfieren electrones a compuestos insolubles como los óxidos férricos. Este estudio revela que las moléculas de menaquinona excretadas facilitan este proceso en Shewanella putrefaciens.
Área de la Ciencia:
- Microbiología Microbiología.
- Ciencias ambientales Ciencias ambientales.
- La bioquímica es la bioquímica.
Sus antecedentes:
- La respiración bacteriana utiliza diversos compuestos como aceptores terminales de electrones, incluidos los minerales insolubles.
- El transporte de electrones a compuestos insolubles como los óxidos férricos es poco conocido en comparación con los aceptores solubles.
- Las sustancias húmicas actúan como aceptores de electrones y transporte de óxidos férricos en entornos anaerobios.
Objetivo del estudio:
- Investigar el mecanismo de la respiración bacteriana en sustancias húmicas.
- Para identificar los genes esenciales para la respiración de los aceptores de electrones insolubles en Shewanella putrefaciens.
- Para dilucidar el papel de las pequeñas moléculas en la transferencia de electrones microbianos a los minerales.
Principales métodos:
- Cribado genético para identificar mutantes de Shewanella putrefaciens incapaces de respirar en sustancias húmicas.
- Análisis de disrupción genética para identificar mutaciones que afectan la respiración de sustancias húmicas.
- Ensayos de complementación que utilizan moléculas excretadas para restaurar la función respiratoria en mutantes.
Principales resultados:
- Los mutantes que carecían de la capacidad de respiración de sustancias húmicas tenían interrupciones en un gen involucrado en la biosíntesis de menaquinona.
- El tipo salvaje de Shewanella putrefaciens libera una molécula relacionada con la menaquinona en el medio.
- Esta molécula excretada restauró la capacidad de los mutantes para respirar sustancias húmicas.
Conclusiones:
- La biosíntesis de menaquinona es crucial para que Shewanella putrefaciens respire sustancias húmicas.
- Las quinonas excretadas por los microbios pueden mediar la transferencia de electrones a oxidantes insolubles, incluidos los minerales.
- Este hallazgo amplía nuestra comprensión del transporte de electrones microbiano y el ciclo biogeoquímico.
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