Gama-Castro S, Núñez C, Segura D, Moreno S, Guzmán J, Espín G
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62250, Mexico.
J Bacteriol. 2001 Nov;183(21):6169-74. doi: 10.1128/JB.183.21.6169-6174.2001.
Encystment in Azotobacter vinelandii is induced by n-butanol or beta-hydroxybutyrate (BHB). We identified a gene, encoding an aldehyde dehydrogenase, that was named aldA. An aldA mutation impaired bacterial growth on n-butanol, ethanol, or hexanol as the sole carbon source. Expression of aldA increased in cells shifted from sucrose to n-butanol and was shown to be dependent on the alternative sigma(54) factor. A mutation in rpoN encoding the sigma(54) factor also impaired growth on alcohols. Encystment on n-butanol, but not on BHB, was impaired in aldA or rpoN mutants, indicating that n-butanol is not an inducer of encystment by itself but must be catabolized in order to induce encystment.