FIG. 6.

Phylogeny of nifH nucleotide sequences using 21 partial nifH gene sequences from the GenBank database and 9 sequences obtained from the cloning of the 250-bp MnlI band from the LCSA-c clay fraction. GenBank database accession numbers are indicated next to the bacterial names. Locations of the nifH fragments used for the analysis correspond to a sequence fragment of ≈250 bp in positions 214 to 476 (referring to the A. vinelandii nifH coding sequence [M20568]). The tree was constructed by the neighbor-joining method, and bootstrap values above 50 from 1,000 resamplings are shown for each node.