PT  - JOURNAL ARTICLE
AU  - Beatrice Bottura
AU  - Liam M. Rooney
AU  - Paul A. Hoskisson
AU  - Gail McConnell
TI  - Intra-colony channel morphology in <em>Escherichia coli</em> biofilms is governed by nutrient availability and substrate stiffness
AID  - 10.1101/2021.12.17.473116
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2021.12.17.473116
4099  - http://biorxiv.org/content/early/2022/08/29/2021.12.17.473116.short
4100  - http://biorxiv.org/content/early/2022/08/29/2021.12.17.473116.full
AB  - Nutrient-transporting channels have been recently discovered in mature Escherichia coli biofilms, however the relationship between intra-colony channel structure and the surrounding environmental conditions is poorly understood. Using a combination of fluorescence mesoscopy and a purpose-designed open-source quantitative image analysis pipeline, we show that growth substrate composition and nutrient availability have a profound effect on the morphology of intra-colony channels in mature E. coli biofilms. Under all nutrient conditions, intra-colony channel width was observed to increase non-linearly with radial distance from the centre of the biofilm. Notably, the channels were around 25% wider at the centre of glucose-limited biofilms compared to ammonium-limited biofilms. Channel density also differed in colonies grown on rich and minimal media, with the former creating a network of tightly packed channels and the latter leading to well-separated, wider channels with defined edges. Our approach paves the way for measurement of internal patterns in a wide range of biofilms, offering the potential for new insights into infection and pathogenicity.Competing Interest StatementThe authors have declared no competing interest.