Reversibility of oxygen switch-off effect on Bacillus polymyxa nitrogenase

Details

Serval ID
serval:BIB_6CFFF8EAA30D
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Reversibility of oxygen switch-off effect on Bacillus polymyxa nitrogenase
Journal
Canadian Journal of Microbiology
Author(s)
Holzmann  H. P., Berghammer  H. A., Ortner  M., Haselwandter  K.
ISSN
0008-4166 (Print)
Publication state
Published
Issued date
10/1991
Volume
37
Number
10
Pages
775-9
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Oct
Abstract
The objective of this study was to analyse in vivo the effect of oxygen on the nitrogenase of Bacillus polymyxa. The culture technique employed in this study prevented spore formation by B. polymyxa during the entire period of exposure to acetylene. Under these conditions the acetylene-reduction assay allowed quantification of nitrogenase activity over long incubation periods (44 h). Nitrogenase activity was highest in cells harvested in the late logarithmic phase. At PO2 of 0.19 and 0.37 kPa, acetylene reduction was inhibited by 80 and 100%, respectively. This switch-off effect could be reversed through oxygen exhaustion, either by flushing the culture with N2 or by cellular respiration, suggesting a respiratory protection mechanism for the nitrogenase complex in B. polymyxa. Oxygen consumption measured by a closed-chamber respirometer showed a linear increase up to a PO2 of 0.2 kPa. Above 0.3 kPa a saturation in oxygen consumption was observed. Exposure to high oxygen pressures resulted in an irreversible loss of nitrogenase activity. The oxygen inhibition pattern was shown to be similar to that in other microaerophilic and anaerobic nitrogen-fixing microorganisms.
Keywords
Bacillus/*enzymology/growth & development/metabolism Kinetics Nitrogen Fixation Nitrogenase/*metabolism Oxygen/*metabolism
Pubmed
Web of science
Create date
25/01/2008 16:08
Last modification date
20/08/2019 14:26
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