Previous Article | Next Article ![]()
Applied and Environmental Microbiology, May 2000, p. 1960-1969, Vol. 66, No. 5
Department of Marine Sciences, University of
Georgia, Athens, Georgia 30602-3636
Received 6 December 1999/Accepted 15 February 2000
The spatial distribution and diversity of ammonia-oxidizing
bacteria of the
0099-2240/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Diversity and Distribution of DNA Sequences with
Affinity to Ammonia-Oxidizing Bacteria of the
Subdivision
of the Class Proteobacteria in the Arctic Ocean
subdivision of the class Proteobacteria
(hereinafter referred to as ammonia oxidizers) in the Arctic Ocean were
determined. The presence of ammonia oxidizers was detected by PCR
amplification of 16S rRNA genes using a primer set specific for this
group of organisms (nitA and nitB, which amplifies a 1.1-kb fragment
between positions 137 and 1234, corresponding to Escherichia
coli 16S rDNA numbering). We analyzed 246 samples collected from
the upper water column (5 to 235 m) during March and April 1995, September and October 1996, and September 1997. Ammonia oxidizers were
detected in 25% of the samples from 5 m, 80% of the samples from
55 m, 88% of the samples from 133 m, and 50% of the samples
from 235 m. Analysis of nitA-nitB PCR product by nested
PCR-denaturing gradient gel electrophoresis (DGGE) showed that all
positive samples contained the same major band (band A), indicating the
presence of a dominant, ubiquitous ammonia oxidizer in the Arctic Ocean basin. Twenty-two percent of the samples contained additional major
bands. These samples were restricted to the Chukchi Sea shelf break,
the Chukchi cap, and the Canada basin; areas likely influenced by
Pacific inflow. The nucleotide sequence of the 1.1-kb nitA-nitB PCR
product from a sample that contained only band A grouped with sequences
designated group 1 marine Nitrosospira-like sequences.
PCR-DGGE analysis of 122 clones from four libraries revealed that 67 to
71% of the inserts contained sequences with the same mobility as band
A. Nucleotide sequences (1.1 kb) of another distinct group of clones,
found only in 1995 samples (25%), fell into the group 5 marine
Nitrosomonas-like sequences. Our results suggest that the
Arctic Ocean
-proteobacterial ammonia oxidizers have low diversity
and are dominated by marine Nitrosospira-like organisms.
Diversity appears to be higher in Western Arctic Ocean regions
influenced by inflow from the Pacific Ocean through the Bering and
Chukchi seas.
*
Corresponding author. Mailing address: Department of
Marine Sciences, University of Georgia, Athens, GA 30602-3636. Phone: (706) 542-3016. Fax: (706) 542-5888. E-mail:
aquadoc{at}uga.edu.
This article has been cited by other articles:
| J. Bacteriol. | Microbiol. Mol. Biol. Rev. | Eukaryot. Cell | All ASM Journals |
|---|