|
|||||
|
|
Oxygen inhibition of nitrogen fixation in cell-free preparations of blue-green algae |
|
| Authors: | P Fay and Rosalie M Cox |
| Institution: | a Department of Botany, Westfield College, University of London, London, N.W. 3, Great Britain b Department of Botany, The University, Bristol, Great Britain |
| Abstract: | 1. Factors inhibiting N2 fixation in cell-free preparations of two blue-green algae, Anabaena cylindrica and Chlorogloea fritschii were investigated. 2. 15N uptake by particulate cell-free fractions of A. cylindrica was less in the light than in the dark, indicating some photo-inhibition of N2 fixation. 3. Anaerobic conditions during preparation and incubation of particulate cell-free fractions of C. fritschii greatly increased their N2-fixing ability. 4. Soluble cell-free material was found to have an inhibitory effect on N2 fixation by particulate cell-free preparations obtained from A. cylindrica. This inhibition was approximately proportional to the amount of soluble fraction supplied to the particulate material. Dialysis of the soluble cell-free fraction did not remove the inhibition which has therefore been attributed to the presence of a soluble enzyme, possibly an oxidase. 5. Dialysis of the soluble cell-free fraction or of particulate material suspended with soluble cell-free fraction resulted in a slight decrease of 15N uptake, indicating the removal by dialysis of small-molecule factors required for N2 fixation. 6. The presence of sulphydryl agents increased the rate of N2 fixation in cell-free preparations of A. cylindrica. |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ | |