Investigations of Structure and Metabolism within Shewanella oneidensis MR-1 Biofilms
Biofilms are known to possess spatially and temporally varying metabolite concentration profiles at the macroscopic and microscopic scales. This results in varying growth environments within that may ultimately drive species diversity, determine biofilm structure and also the spatial arrangement of the community members. Using noninvasive nuclear magnetic resonance (NMR) microscopic imaging/spectroscopy and confocal imaging, we investigated anaerobic reduction kinetics, structural variation, and the stratification of metabolism within live biofilms of the facultative anaerobic dissimilatory metal-reducing Shewanella oneidensis strain MR-1. Biofilms were pregrown using a defined minimal media in a homebuilt constant depth film fermenter and subsequently transferred to an in-magnet sample chamber under laminar flow for NMR measurements. The sample was subjected to various, rapidly switched substrate/ anaerobic electron acceptor combinations (fumarate, dimethyl sulfoxide, and nitrate electron acceptors). Localized NMR spectroscopy was used to non-invasively monitored the spectra of hydrogen-containing metabolites at high temporal resolution (4.5 min) under oxygen-limited conditions. Anaerobic reduction was immediately observed upon switching feed solutions indicate that no gene induction (transcriptional response) was needed for MR-1 to switch between fumarate, dimethyl sulfoxide (DMSO) and nitrate electron acceptors. In parallel experiments, confocal microscopy was used with constitutively expressed fluorescent reporters to independently investigate structural changes in response to the availability of electron acceptor and also the outcome of metabolic competition under oxygen-limited conditions. A clearer understanding of the metabolic diversity and plasticity of the biofilm mode of growth as well as how this possibly translates to the environmental fitness is made possible through the use of non-invasive and non-destructive techniques such as described here.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 935602
- Report Number(s):
- PNNL-SA-56667; 16090c
- Journal Information:
- Journal of Microbiological Methods, 74(1):47-56, Journal Name: Journal of Microbiological Methods, 74(1):47-56 Journal Issue: 1 Vol. 74; ISSN JMIMDQ; ISSN 0167-7012
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BINDING ENERGY
DMSO
ELECTRONS
Environmental Molecular Sciences Laboratory
GENES
INDUCTION
KINETICS
LAMINAR FLOW
METABOLISM
METABOLITES
MICROSCOPY
NITRATES
NUCLEAR MAGNETIC RESONANCE
PLASTICITY
RESOLUTION
SPECIES DIVERSITY
SPECTRA
SPECTROSCOPY
STRAINS
STRATIFICATION
VALENCE