eCite Digital Repository

A method for the use of the radiotracer 55Fe for microautoradiography and CARD-FISH of natural bacterial communities


Fourquez, MAC and Obernosterer, I and Blain, S, A method for the use of the radiotracer 55Fe for microautoradiography and CARD-FISH of natural bacterial communities, F E M S Microbiology Letters: (Federation of European Microbiological Societies), 337, (2) pp. 132-139. ISSN 0378-1097 (2012) [Refereed Article]

Copyright Statement

Copyright 2012 Federation of European Microbiological Societies

DOI: doi:10.1111/1574-6968.12022


Heterotrophic bacteria are key players in the biogeochemical cycle of iron (Fe) in the ocean, but the capability of different bacterial groups to access this micronutrient is ignored thus far. The aim of our study was to develop a protocol for the combined application of microautoradiography (MICRO) and catalyzed reporter deposition–fluorescence in situ hybridization (CARD-FISH) using the radioisotope 55Fe. Among the different washing solutions tested, Ti-citrate-EDTA was the most efficient for the removal of extracellular 55Fe providing sufficiently low background values. We further demonstrate that the washing of cells with Ti-citrate-EDTA and the fixation with paraformaldehyde or formaldehyde do not induce leakage of intracellular 55Fe. Incubating natural bacterial communities collected from contrasting environments, the NW Mediterranean Sea and the Southern Ocean, with 55Fe revealed that 3–29% of bacterial cells were associated with silver grains. Combining microautoradiography with CARD-FISH, we demonstrate that the contribution of different bacterial groups to total 55Fe-incorporating cells was overall reflected by their relative contribution to abundance. An exception to this pattern was the proportionally higher contribution of Gammaproteobacteria, SAR86 and Alteromonas. Our study demonstrates the feasibility of MICRO-CARD-FISH using the radiotracer 55Fe and provides the first description of marine bacterial assemblages actively incorporating Fe.

Item Details

Item Type:Refereed Article
Keywords:55 Fe; CARD-FISH; marine bacteria; microautoradiography
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological oceanography
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Antarctic and Southern Ocean oceanic processes
UTAS Author:Fourquez, MAC (Dr Marion Fourquez)
ID Code:91585
Year Published:2012
Web of Science® Times Cited:7
Deposited By:IMAS Research and Education Centre
Deposited On:2014-05-22
Last Modified:2015-02-02

Repository Staff Only: item control page