HYDROGEN UPTAKE IN NOSTOC STRAIN PCC-73102 - EFFECTS OF NICKEL, HYDROGEN, CARBON AND NITROGEN

• Tipo: Artigo em Revista Científica Internacional
• Data: 1995

Autores

OXELFELT, F (Autor) Outra; TAMAGNINI, P (Autor) FCUP; SALEMA, R (Autor) Outra; LINDBLAD, P (Autor) Outra

Revista

Título: Plant Physiology and Biochemistry

Vol. 33

Páginas: 617-623

ISSN: 0981-9428

Editora: Elsevier

Indexação

ISI Web of Knowledge - 53 Citações

Scopus - 49 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Ciências biológicas

Outras Informações

ID Authenticus: P-001-G3Y

Abstract (EN): The uptake hydrogenase activity was characterized in Nostoc sp. strain PCC 73102, a free-living filamentous heterocystous cyanobacterium originally isolated from coralloid roots of the cycad Macrozamia sp., using a H-2-electrode. We demonstrate the presence of a light-dependent hydrogen uptake activity in nitrogen-fixing cells. The uptake was stimulated by addition of Ni2+ to the growth medium up to a concentration of 5 mu M Cultures, grown in continuous light in the presence of 9% H-2, showed a clear enhancement of the hydrogen uptake. A temporary stimulation of the light-dependent hydrogen uptake activity was also achieved by adding 9% of H-2 to cells incubated in darkness. Cells grown heterotrophically in complete darkness, reached four times higher light-dependent hydrogen uptake than photoautotrophically grown cells. Addition of the protein synthesis inhibitor chloramphenicol to heterotrophically grown cells, abolished the increase observed by the presence of organic carbon, indicating a regulation at the protein synthesis level and not by a regulation of pre-existing enzyme/subunit(s). No uptake activity was observed in cells incubated in darkness only. In cultures grown with the presence of 5 mM ammonium chloride, significant reductions in both nitrogenase and light-dependent uptake hydrogenase activity were observed. In summary, Hz, either added from an external source or produced through the action of nitrogenase, induced high in vivo light-dependent hydrogen uptake in the free-living cyanobacterium Nostoc PCC 73102.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 7