FIG. 5.

Nitrogen fixation of the wild type and the fdxN deletion mutant in coculture. (A) Nitrogen fixation was measured as the amount of acetylene reduction per flask of Acremonium alternatum 2003 cocultured with Azoarcus sp. strain BH72 (circles) or with the mutant BHΔfdxN (squares). (B) Western blot analysis of cocultures with BH72 (lanes a) or BHΔfdxN (lanes b). Total protein extract of the coculture was diluted 2-fold (lanes 1) and 10-fold (lanes 2) and used for Western blot analysis with antibodies directed against the Fe protein of nitrogenase (34 and 37 kDa).