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Marozava, S. ; Merl-Pham, J. ; Müller, H.* ; Meckenstock, R.U.*

Adaptation of carbon source utilization patterns of Geobacter metallireducens during sessile growth.

Front. Microbiol. 11:1271 (2020)
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There are two main strategies known how microorganisms regulate substrate utilization: specialization on one preferred substrate at high concentrations in batch cultures or simultaneous utilization of many substrates at low concentrations in chemostats. However, it remains unclear how microorganisms utilize substrates at low concentrations in the subsurface: do they focus on a single substrate and exhibit catabolite repression or do they de-repress regulation of all catabolic pathways? Here, we investigated the readiness ofGeobacter metallireducensto degrade organic substrates under sessile growth in sediment columns in the presence of a mixed community as a model for aquifers. Three parallel columns were filled with sand and flushed with anoxic medium at a constant inflow (18 ml h(-1)) of the substrate benzoate (1 mM) with non-limiting nitrate concentrations (30 mM) as electron acceptor. Columns were inoculated with the anaerobic benzoate degraderG. metallireducens. Microbial degradation produced concentration gradients of benzoate toward the column outlet. Metagenomics and label-free metaproteomics were used to detect and quantify the protein expression ofG. metallireducens. Bulk benzoate concentrations below 0.2 mM led to increased abundance of catabolic proteins involved in utilization of fermentation products and aromatic compounds including the complete upregulation of the toluene-degrading pathway although toluene was not added to the medium. We propose that under sessile conditions and low substrate concentrationsG. metallireducensexpresses a specific set of catabolic pathways for preferred substrates, even when these substrates are not present.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Microbial Physiology ; Geobacter Metallireducens ; Label-free Proteomics ; Sessile Growth ; Carbon Limitation ; Sediment Columns; Geobacter-metallireducens; Field Experiments; Label-free; Iron; Physiology; Expression; Identification; Limitation; Reduction; Proteome
ISSN (print) / ISBN 1664-302X
e-ISSN 1664-302X
Quellenangaben Volume: 11, Issue: , Pages: , Article Number: 1271 Supplement: ,
Publisher Frontiers
Publishing Place Avenue Du Tribunal Federal 34, Lausanne, Ch-1015, Switzerland
Non-patent literature Publications
Reviewing status Peer reviewed