Electronic Resource
Springer
Archives of microbiology
101 (1974), S. 401-408
ISSN:
1432-072X
Keywords:
Hydrogenase
;
Nitrogen Fixation
;
Blue-Green Algae
;
Heterocysts
;
Electron Transport
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Hydrogen-supported nitrogenase activity was demonstrated in Anabaena cylindrica cultures limited for reductant. Nitrogen-fixing Anabaena cylindrica cultures sparged in the light with anaerobic gases in the presence of the photosynthesis inhibitor DCMU slowly lost their ability to reduce acetylene in the light under argon but exhibited near normal activities in the presence of 11% H2 (balance argon). The hydrogen-supported nitrogenase activity was half-saturated between 2 and 3% H2 and was strongly inhibited by oxygen (50% inhibition at about 5–6% O2). Batch cultures of Anabaena cylindrica approaching stationary growth phase (“old” cultures) lost nitrogenase-dependent hydrogen evolution almost completely. In these old cultures hydrogen relieved the inhibitory effects of DCMU and O2 on acetylene reduction. Our results suggest that heterocysts contain an uptake hydrogenase which supplies an electron transport chain to nitrogenase but which couples only poorly with the respiratory chain in heterocysts and does not function in CO2 fixation by vegetative cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00455956
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