C2H2reduction, oxygen uptake and cytochromecreduction by bacteroids isolated from French-bean nodules

✍ Scribed by J. C. Trinchant; A. M. Birot; M. Denis; J. Rigaud

• Book ID: 104761216
• Publisher: Springer
• Year: 1983
• Tongue: English
• Weight: 491 KB
• Volume: 134
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00407755

✦ Synopsis

Low concentration of dissolved 0 2 (3 gM) induced a significant C2H~ reduction by bacteroids isolated from French-beans (Phaseolus vulgaris) inoculated with Rhizobium phaseoli strain 9 -6. This activity, determined with or without glucose, declined with increasing 02 concentrations in spite of the generation of a substantial level of ATP. Under these conditions, cytochrome e studied by a rapid spectrometry method on whole cells, appeared more than 80% oxidized. An active C2I-I 2 reduction always corresponded to a high level of cyt c reduction observed with glucose, at low 02 tensions only, and with succinate for a larger range of pO2 values. Our results indicated that inability of glucose to support C2H2 reduction activity for higher 02 tensions was due to a limiting electron allocation to nitrogenase in relation with the poor level of reduced cyt c observed in these conditions.