title: Diversity and abundance of ammonia-oxidizing bacteria in eutrophic and  oligotrophic basins of a shallow Chinese lake (Lake Donghu).
abstract: Classical cultivation and molecular methods based on the ammonia monooxygenase gene (amoA) were used to study the abundance and diversity of beta-proteobacterial ammonia-oxidizing bacteria (AOB) in lake sediments. The eutrophic and oligotrophic basins of a Chinese shallow lake (Lake Donghu), in terms of ammonium (NH(+)(4)) concentrations, were sampled. The AOB number was significantly lower in the oligotrophic basin, but significantly higher in the eutrophic basin. In addition, using restriction fragment length polymorphism targeting the amoA, ten restriction patterns including six unique ones were found in the eutrophic basin, while five patterns were observed in the oligotrophic basin with only one unique restriction group. Phylogenetic analysis for AOB revealed that Nitrosomonas oligotropha- and Nitrosomonas ureae-related AOB and Nitrosospira-affiliated AOB were ubiquitous; the former dominated in the eutrophic basin (87.2%), while the latter dominated in the oligotrophic basin (65.5%). Furthermore, Nitrosomonas communis-related AOB was only detected in the eutrophic basin, at a small proportion (3.2%). These results indicate significant selection and adaptation of sediment AOB in lakes with differing trophic status.
authors.affiliation: Laboratory of Water Environmental Biochemistry, Institute of Hydrobiology, The Chinese Academy of Sciences, Hubei, China. cgy1117@yahoo.com.cn
authors.forename: Guo-Yuan
authors.initials: GY
authors.lastname: Chen
authors.forename: Shan-Lian
authors.initials: SL
authors.lastname: Qiu
authors.forename: Yi-Yong
authors.initials: YY
authors.lastname: Zhou
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D020562:Betaproteobacteria / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism*; D044822:Biodiversity; D002681:China; D016000:Cluster Analysis; D015169:Colony Count, Microbial; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005618:Fresh Water / Q000382:microbiology; D019015:Geologic Sediments / Q000382:microbiology*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D000641:Ammonia; D010088:Oxidoreductases; C045582:ammonia monooxygenase