Characterization of a ferric uptake regulator (Fur)-mutant of the cyanotrophic bacterium Pseudomonas pseudoalcaligenes CECT5344.
The Fur protein is the main sensor of cellular iron status in bacteria. In the present study, we inactivated the fur gene of Pseudomonas pseudoalcaligenes CECT5344 and characterized the resulting mutant. Our findings provide experimental evidence that, cyanide generates an intracellular signal equivalent to that triggered by iron deprivation, as witnessed by the induction of prrF and fiuA (ferrichrome receptor) expression in the presence of cyanide. The fur mutant also displayed slow growth, especially in minimal culture medium, increased sensitivity to cyanide in LB medium and as expected, resistance to manganese ions. Moreover, the mutant exhibited enhanced iron accumulation and increased sensitivity to streptonigrin, as well as to some inducers of oxidative stress, such as paraquat and menadione, yet it remained resistant to hydrogen peroxide. Surprisingly, neither the wild type strain nor the fur mutant strain produced siderophores that could be detected using the universal CAS-agar method.
Departamento de Bioquímica y Biología Molecular y Genética Facultad de Veterinaria, Universidad de Extremadura, Avenida de la Universidad s/n, 10003 Cáceres, Spain.
Gracia
G
Becerra
Departamento de Bioquímica y Biología Molecular y Genética Facultad de Veterinaria, Universidad de Extremadura, Avenida de la Universidad s/n, 10003 Cáceres, Spain.
Faustino
F
Merchán
Departamento de Bioquímica y Biología Molecular y Genética Facultad de Veterinaria, Universidad de Extremadura, Avenida de la Universidad s/n, 10003 Cáceres, Spain.
Rafael
R
Blasco
Departamento de Bioquímica y Biología Molecular y Genética Facultad de Veterinaria, Universidad de Extremadura, Avenida de la Universidad s/n, 10003 Cáceres, Spain. Electronic address: migeno@unex.es.
M Isabel
MI
Igeño
D001426:Bacterial Proteins / Q000235:genetics*; D003486:Cyanides / Q000378:metabolism / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007501:Iron / Q000378:metabolism; D009154:Mutation; D018384:Oxidative Stress / Q000187:drug effects; D010641:Phenotype; D044205:Pseudomonas pseudoalcaligenes / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics*; D013308:Streptonigrin / Q000494:pharmacology
D001426:Bacterial Proteins; D003486:Cyanides; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial; D013308:Streptonigrin; D006861:Hydrogen Peroxide; D007501:Iron
Cyanide biodegradation; Iron; fiuA; fur; prrF