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Title (Primary) Tracing the slow growth of anaerobic methane-oxidizing communities by 15N-labelling techniques
Author Krüger, M.; Wolters, H.; Gehre, M.; Joye, S.B.; Richnow, H.H.;
Journal FEMS Microbiology Ecology
Year 2008
Department ISOBIO;
Volume 63
Issue 3
Language englisch;
Keywords stable isotopes; anaerobic methane oxidation; growth yield; microbial growth; amino acids
Abstract The anaerobic oxidation of methane (AOM) is an important methane sink in marine ecosystems mediated by still uncultured Archaea. We established an experimental system to grow AOM communities in different sediment samples. Approaches to show growth of the slow-growing anaerobic methanotrophs have been either via nucleic acids (quantitative PCR) or required long-term incubations. Previous long-term experiments with 13C-labelled methane led to an unspecific distribution of the 13C-label. Although quantitative PCR is a sensitive technique to detect small changes in community composition, it does not determine growth yield. Therefore, we tested an alternative method to detect a biomass increase of AOM microorganisms with 15N-labelled ammonium as N-source. After only 3 weeks, significant 15N-labelling became apparent in amino acids as major structural units of microbial proteins. This was especially evident in methane-containing incubations, showing the methane-dependent uptake of the 15N-labelled ammonium by microorganisms. Cell counts demonstrated a two- and fourfold increase at ambient or elevated methane concentrations. With denaturing gradient gel electrophoresis, over 6 months incubation no changes in community composition of sulphate-reducing bacteria and archaea were detected. These data indicate doubling times for AOM microorganisms between 2 and 3.4 months. In conclusion, the 15N-labelling approach proved to be a sensitive and fast way to show growth of extremely slow-growing microorganisms.
ID 1149
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=1149
Krüger, M., Wolters, H., Gehre, M., Joye, S.B., Richnow, H.H. (2008):
Tracing the slow growth of anaerobic methane-oxidizing communities by 15N-labelling techniques
FEMS Microbiol. Ecol. 63 (3), 401 - 411