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. 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 4. Nitrogenase activity in R. rubrum strains containing single or multiple copies of R. rubrum nifA when grown in MG (nitrogen-limiting) or MN (NH4+ -free) media.

Strain Plasmid (gene) Nitrogenase activity*

MG (nitrogen-limiting) MN (NH4+-free)
UR2 (wild-type) None (single copy of R. rubrum nifA) 800 400
UR717 (ΔglnB3) None (single copy of R. rubrum nifA) <10 <10
UR741 (wild-type) pYPZ239 (multicopy of R. rubrum nifA) 650 300
UR744 (ΔglnB3) pYPZ239 (multicopy of R. rubrum nifA) 50 280
*

Units of nitrogenase activity are expressed as in Table 2.

Nitrogenase activities of these strains in MG medium are similar to those recorded previously (Zhang et al., 2001a).

UR717 grew very slowly in MN medium, with a final OD600 of 0.3 after 2 days of growth, while UR2 and UR741 had a final OD600 of ∼3. UR744 grew slightly slower in MN medium, with a final OD600 of 1.7.