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In Situ Characterization of Shewanella oneidensis MR1 Biofilms by SALVI and ToF-SIMS
Published on: August 18, 2017
Reconocimiento bacteriano de las superficies minerales: interacciones a nanoescala entre Shewanella y alfa-FeOOH
S K Lower1, M F Hochella, T J Beveridge
1NanoGeoscience and Technology Laboratory, Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. slower@vt.edu
Science (New York, N.Y.)
|May 19, 2001
Resumen
Las bacterias Shewanella oneidensis muestran una mayor afinidad por el mineral goetita en condiciones anaerobias. Esta interacción, facilitada por una putativa reductasa de hierro, es crucial para la reducción de metales microbianos en entornos cercanos a la superficie.
Área de la Ciencia:
- Microbiología Microbiología.
- La geoquímica es la geoquímica.
- La biofísica es la biofísica.
Sus antecedentes:
- Shewanella oneidensis es una bacteria disimiladora reductora de metales.
- La goethita (alfa-FeOOH) es un mineral oxihidróxido de hierro común en los entornos cercanos a la superficie de la Tierra.
- La comprensión de las interacciones entre bacterias y minerales es clave para el ciclo biogeoquímico.
Objetivo del estudio:
- Para medir cuantitativamente las fuerzas entre S. oneidensis y goethite.
- Para investigar el efecto de las condiciones ambientales (aeróbicas vs. anaeróbicas) en las interacciones célula-mineral.
- Identificar los mecanismos moleculares que facilitan la transferencia de electrones.
Principales métodos:
- Se utilizó la microscopía de fuerza para medir fuerzas infinitesimales entre las células vivas de S. oneidensis y la goetita.
- Mediciones realizadas en tiempo real bajo diferentes distancias y condiciones de solución (aeróbica / anaeróbica).
- Analizó las curvas de fuerza para derivar valores de energía e identificar firmas de interacción.
Principales resultados:
- Se observó un aumento de dos a cinco veces en la afinidad S. oneidensis-goetita bajo condiciones anaerobias.
- Se demostró que el aumento de la afinidad se correlaciona con la transferencia esperada de electrones anaerobios.
- Se identificaron firmas específicas de la curva de fuerza que sugieren la movilización de una supuesta reductasa de hierro de 150 kDa.
Conclusiones:
- Las condiciones anaerobias mejoran significativamente la afinidad de unión entre S. oneidensis y goethite.
- Una putativa reductasa de hierro en la membrana externa bacteriana juega un papel en la facilitación de la transferencia de electrones a la goetita.
- Estos hallazgos proporcionan información molecular sobre los procesos microbianos de reducción de metales.
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