Ammonia-oxidizing beta-Proteobacteria from the oxygen minimum zone off northern Chile
The composition of ammonia-oxidizing bacteria from the Î²- Proteobacteria subclass (Î²AOB) was studied in the surface and upper-oxycline oxic waters (2- to 50-m depth, âˆ¼200 to 44 mu;M O 2) and within the oxygen minimum zone (OMZ) suboxic waters (50- to 400-m depth, â‰¤10 Î¼M O 2) of the eastern South Pacific off northern Chile. This study was carried out through cloning and sequencing of genes coding for 16S rRNA and the ammonia monooxygenase enzyme active subunit (amoA). Sequences affiliated with Nitrosospira-like cluster 1 dominated the 16S rRNA gene clone libraries constructed from both oxic and suboxic waters. Cluster 1 consists exclusively of yet-uncultivated Î²AOB from marine environments. However, a single clone, out of 224 obtained from the OMZ, was found to belong to Nitrosospira lineage cluster 0. To our knowledge, cluster 0 sequences have been derived from Î²AOB isolated only from sand, soil, and freshwater environments. Sequences in clone libraries of the amoA gene from the surface and upper oxycline could be grouped in a marine subcluster, also containing no cultured representatives. In contrast, all 74 amoA sequences originating from the OMZ were either closely affiliated with cultured Nitrosospira spp. from clusters 0 and 2 or with other yet-uncultured Î²AOB from soil and an aerated-anoxic Orbal process waste treatment plant. Our results reveal the presence of Nitrosospira-like Î²AOB in both oxic and suboxic waters associated with the OMZ but with a clear community shift at the functional level (amoA) along the strong oxygen gradient. Copyright Â© 2007, American Society for Microbiology. All Rights Reserved.
|Título según WOS:||Ammonia-oxidizing beta-Proteobacteria from the oxygen minimum zone off northern Chile|
|Título según SCOPUS:||Ammonia-oxidizing ß-proteobacteria from the oxygen minimum zone off Northern Chile|
|Título de la Revista:||APPLIED AND ENVIRONMENTAL MICROBIOLOGY|
|Editorial:||AMER SOC MICROBIOLOGY|
|Fecha de publicación:||2007|
|Página de inicio:||3547|