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Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Fijación de nitrógeno por Azotobacter vinelandii cepas que tienen deleciones en genes estructurales para la
Science (New York, N.Y.)
|April 4, 1986
Resumen
Azotobacter vinelandii tiene dos sistemas de fijación de nitrógeno. Las cepas de eliminación confirmaron un sistema alternativo de fijación de nitrógeno, no solo cambios fenotípicos en condiciones de deficiencia de molibdeno.
Área de la Ciencia:
- Microbiología Microbiología.
- La bioquímica es la bioquímica.
- Genética La genética.
Sus antecedentes:
- Azotobacter vinelandii exhibe una reversión fenotípica en la fijación del nitrógeno bajo deficiencia de molibdeno.
- Este fenómeno sugería la presencia de dos sistemas distintos de fijación de nitrógeno.
Objetivo del estudio:
- Investigar la existencia de un sistema alternativo de fijación de nitrógeno en Azotobacter vinelandii.
- Para diferenciar entre un sistema alternativo y la expresión génica alterada.
Principales métodos:
- Construcción de cepas de deleción que carecen de genes nitrogenasa convencionales (nifHDK).
- Cepas de cultivo en medios libres de nitrógeno con deficiencia de molibdeno.
- Evaluar el crecimiento, la reducción de acetileno y la incorporación de nitrógeno-15.
Principales resultados:
- Las cepas de eliminación crecieron en medios deficientes en molibdeno.
- Estas cepas mostraron bajas tasas de reducción de acetileno y incorporación de nitrógeno-15.
- Se confirmó que la reversión fenotípica es independiente de la disponibilidad de molibdeno.
Conclusiones:
- El estudio confirma la existencia de un sistema alternativo de fijación de nitrógeno en Azotobacter vinelandii.
- Este sistema alternativo funciona independientemente de la nitrogenasa dependiente de molibdeno convencional.
- Los hallazgos validan la hipótesis inicial de un sistema dual de fijación de nitrógeno.
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