. Author manuscript; available in PMC: 2012 Oct 31.

Published in final edited form as: Microbiology (Reading). 2008 Sep;154(Pt 9):2689–2699. doi: 10.1099/mic.0.2008/019406-0

Table 2. Nitrogenase activity in the ΔglnB or the ΔglnD mutant with wild-type or altered nifA integrated into the chromosome when grown in MG (nitrogen-limiting) medium.

UR strain	nifA integrated into DglnB or DglnD background	Nitrogenase activity^*
UR1739	Wild-type nifA integrated into ΔglnB mutant (UR717)	<10
UR1740	nifA11 (encoding NifA-M173I) integrated into ΔglnB mutant (UR717)	470
UR1741	nifA12 (encoding NifA-M173V) integrated into ΔglnB mutant (UR717)	450
UR1742	Wild-type nifA integrated into ΔglnD mutant (UR1325)	<10
UR1743	nifA11 (encoding NifA-M173I) integrated into ΔglnD mutant (UR1325)	200
UR1744	nifA12 (encoding NifA-M173V) integrated into ΔglnD mutant (UR1325)	230

Each unit of nitrogenase activity is expressed as nanomoles ethylene produced per hour per millilitre of cells at an OD₆₀₀ of 1. Each activity value is from at least five replicate assays from different individually grown cultures. SD, 5–15 %.