Adenine nucleotide levels in and nitrogen fixation by the cyanobacterium Anabaena sp. strain 7120.
AUTOR(ES)
Privalle, L S
RESUMO
Adenine nucleotide levels were determined in whole filaments of Anabaena sp. 7120 grown under different N2-fixing or non-N2-fixing conditions. These were compared with levels in isolated heterocysts, Rhodospirillum rubrum, and Azotobacter vinelandii. Adenine nucleotides in whole filaments of Anabaena sp. do not reflect the energetic expense of N2 fixation as they do in R. rubrum and A. vinelandii. However, adenine nucleotide levels in heterocysts were similar to the levels found in N2-fixing R. rubrum, i.e., an ATP:ADP ratio near 1 and an energy charge between 0.5 and 0.7. Nitrogenase activity was only 50% of optimal in permeabilized heterocysts at an exogenous ATP:ADP ratio of 3.33. Hydrogen, which increases acetylene reduction activity, also causes a transient increase (2 to 5 min) in the ATP:ADP ratio. Hydrogen has little effect on energy charge.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=217466Documentos Relacionados
- Isolation and complementation of nitrogen fixation mutants of the cyanobacterium Anabaena sp. strain PCC 7120.
- Protein tyrosine phosphorylation in the cyanobacterium Anabaena sp. strain PCC 7120.
- Lipopolysaccharide dependence of cyanophage sensitivity and aerobic nitrogen fixation in Anabaena sp. strain PCC 7120.
- Activities of two dissimilar thioredoxins from the cyanobacterium Anabaena sp. strain PCC 7120.
- A vector for analysis of promoters in the cyanobacterium Anabaena sp. strain PCC 7120.