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ID 20780
file
creator
Ito, Tsukasa
Okabe, Satoshi
NDC
Construction. Civil engineering
abstract
Ecophysiological interactions between the community members (i.e., nitrifiers and heterotrophic bacteria) in a carbon-limited autotrophic nitrifying biofilm fed only NH4+ as an energy source were investigated by using a full-cycle 16S RRNA approach followed by microautoradiography (MAR)-fluorescence in situ hybridization (FISH). Phylogenetic differentiation (identification) of heterotrophic bacteria was performed by 16S rRNA gene sequence analysis, and FISH probes were designed to determine the community structure and the spatial organization (i.e., niche differentiation) in the biofilm. FISH analysis showed that this autotrophic nitrifying biofilm was composed of 50% nitrifying bacteria (ammonia-oxidizing bacteria [AOB] and nitrite-oxidizing bacteria [NOB]) and 50% heterotrophic bacteria, and the distribution was as follows: members of the alpha subclass of the class Proteobacteria (α-Proteobacteria), 23%; γ-Proteobacteria, 13%; green nonsulfur bacteria (GNSB), 9%; Cytophaga-Flavobacterium-Bacteroides (CFB) division, 2%; and unidentified (organisms that could not be hybridized with any probe except EUB338), 3%. These results indicated that a pair of nitrifiers (AOB and NOB) supported a heterotrophic bacterium via production of soluble microbial products (SMP). MAR-FISH revealed that the heterotrophic bacterial community was composed of bacteria that were phylogenetically and metabolically diverse and to some extent metabolically redundant, which ensured the stability of the ecosystem as a biofilm. α- and γ -Proteobacteria dominated the utilization of [14C]acetic acid and 14C-amino acids in this biofilm. Despite their low abundance (ca. 2%) in the biofilm community, members of the CFB cluster accounted for the largest fraction (ca. 64%) of the bacterial community consuming N-acetyl-D-[1- 14C]glucosamine (NAG). The GNSB accounted for 9% of the 14C-amino acid-consuming bacteria and 27% of the [ 14C]NAG-consuming bacteria but did not utilize [14C] acetic acid. Bacteria classified in the unidentified group accoun
journal title
Applied and Environmental Microbiology
volume
Volume 70
issue
Issue 3
start page
1641
end page
1650
date of issued
2004-03
publisher
American Society for Microbiology
issn
0099-2240
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
Copyright (c) American Society for Microbiology
relation url
department
Graduate School of Engineering



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