The cyanotrophic bacterium Pseudomonas pseudoalcaligenes CECT5344 responds to cyanide by defence mechanisms against iron deprivation, oxidative damage and nitrogen stress

Authors

  • Victor M. Luque-Almagro,

    1. Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
    2. Department of Microbiology and Molecular Biology, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
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  • María J. Huertas,

    1. Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
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  • M. Dolores Roldán,

    1. Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
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  • Comrado Moreno-Vivián,

    1. Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
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  • Manuel Martínez-Luque,

    1. Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
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  • Rafael Blasco,

    1. Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad de Extremadura, 11071 Cáceres, Spain.
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  • Francisco Castillo

    Corresponding author
    1. Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
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*E-mail bb1carof@uco.es; Tel. (+34) 957 218318; Fax (+34) 957 218588.

Summary

Two-dimensional (2-D) electrophoresis approach has been used to test protein expression changes in response to cyanide in the alkaliphilic bacterium Pseudomonas pseudoalcaligenes CECT5344. This is a cyanide-assimilating strain which also grows in media containing cyanide-enriched effluent from the jewellery industry. The bacterium efficiently uses this residue as the sole nitrogen source for aerobic growth under alkaline pH with negligible nitrogen losses as HCN. Cell-free extracts isolated from P. pseudoalcaligenes grown with a jewellery residue, free cyanide or ammonium chloride as nitrogen source were subjected to 2-D electrophoresis and the spot patterns were examined to determine differential protein expression. Electrophoretic plates exhibiting an average of 1000 spots showed significant differences in the expression of about 44 proteins depending on the nitrogen source. Some of these protein spots were analysed by Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). Characterization of five of these proteins reveals that cyanide shock induces proteins related to iron acquisition, regulation of nitrogen assimilation pathways and oxidative stress repairing and protection.

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