RESUMO
As molybdenum (Mo) is an indispensable metal for plant nitrogen metabolisms, accumulation of dissolved Mo into bacterial cells may connect to the development of bacterial fertilizers that promote plant growth. In order to enhance Mo bioaccumulation, nitrogen removal and light illumination were examined in anoxygenic photosynthetic bacteria (APB) because APB possess Mo nitrogenase whose synthesis is strictly regulated by ammonium ion concentration. In addition, an APB, Rhodopseudomonas palustris, transformed with a gene encoding Mo-responsive transcriptional regulator ModE was constructed. Mo content was most markedly enhanced by the removal of ammonium ion from medium and light illumination while their effects on other metal contents were limited. Increases in contents of trace metals including Mo by the genetic modification were observed. Thus, these results demonstrated an effective way to enrich Mo in the bacterial cells by the culture conditions and genetic modification.
Assuntos
Apoproteínas/genética , Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Molibdênio/metabolismo , Molibdoferredoxina/genética , Nitrogênio/deficiência , Rodopseudomonas/metabolismo , Fatores de Transcrição/genética , Compostos de Amônio/metabolismo , Compostos de Amônio/farmacologia , Anaerobiose , Apoproteínas/metabolismo , Proteínas de Bactérias/metabolismo , Engenharia Genética , Luz , Molibdoferredoxina/metabolismo , Rodopseudomonas/genética , Rodopseudomonas/efeitos da radiação , Fatores de Transcrição/metabolismo , Transcrição GênicaRESUMO
An oligopeptide permease family ATP-binding cassette (ABC) transporter encoded by SGR2418-SGR2414 was shown to be essential for aerial mycelium formation on glucose-containing media in Streptomyces griseus. In spite of only weak sequence similarity, the operon was equivalent to the bldK operon of Streptomyces coelicolor A3(2) in terms of chromosomal location and function. Transcription of the operon appeared not to be directly regulated by AdpA, a global regulator of morphological and physiological development in S. griseus, although it was affected by adpA inactivation. This study revealed that an ABC transporter was essential for aerial mycelium formation not only in S. coelicolor A3(2) but also in S. griseus, indicating that extracellular signaling by certain peptides should be conserved among different Streptomyces species.