Topography quantifications allow for identifying the contribution of parental strains to physical properties of co-cultured biofilms

Abstract

Most biofilm research has so far focused on investigating biofilms generated by single bacterial strains. However, such single-species biofilms are rare in nature where bacteria typically coexist with other microorganisms. Although, from a biological view, the possible interactions occurring between different bacteria are well studied, little is known about what determines the material properties of a multi-species biofilm. Here, we ask how the co-cultivation of two B. subtilis strains affects certain important biofilm properties such as surface topography and wetting behavior. We find that, even though each daughter colony typically resembles one of the parent colonies in terms of morphology and wetting, it nevertheless exhibits a significantly different surface topography. Yet, this difference is only detectable via a quantitative metrological analysis of the biofilm surface. Furthermore, we show that this difference is due to the presence of bacteria belonging to the ‘other’ parent strain, which does not dominate the biofilm features. The findings presented here may pinpoint new strategies for how biofilms with hybrid properties could be generated from two different bacterial strains. In such engineered biofilms, it might be possible to combine desired properties from two strains by co-cultivation.

Wetting and Imbibition Characteristics of Pseudomonas fluorescens Biofilms Grown on Stainless Steel

“…On the contrary, higher S dr values indicate two hydrophobic behaviors, either the rose-like one (S dr ∼ 200%) or the lotuslike one (S dr > 400%). 9,22,46 Estimations of S dr in this study yield values lower than 10% in all cases. The small values of profile roughness and the respective profile shapes along with the S dr values less than 100% indicate biofilms of hydrophilic nature (in all the three examined biofilm incubation periods).…”

Biofilm hydrophobicity in environmental isolates of Bacillus subtilis

“…It is therefore possible that the isolates used here, which have been extracted from a natural environment where they are likely to have existed in mixed communities, have diversified into non-hydrophobic variants, despite encoding bslA. Consistent with this, the intentional mixing of wild-type isolates of B. subtilis that exhibit different surface wetting properties in single culture alters the properties and morphology of the blended isolate community that develops [36].…”

“…Consistent with this, the intentional mixing of wild-type isolates of B. subtilis that exhibit different surface wetting properties in single culture alters the properties and morphology of the blended isolate community that develops [36].…”

Vertical growth dynamics of biofilms

“…The characterization of microbial topographies is a growing field (Dervaux et al, 2014;Larimer et al, 2016;Kesel et al, 2017;Werb et al, 2017;Schiebel et al, 2020;Paula et al, 2020;Hayta et al, 2021;Mahto and Das, 2021), but with limited focus on the temporal dynamics of the colony.…”

“…The characterization of microbial topographies is a growing field (31)(32)(33)(34)(35)(36)(37)(38), but with limited focus on the temporal dynamics of the colony. The lack of clarity about vertical growth dynamics is due in part to the experimental difficulty in measuring the height of a biofilm with sufficient precision over many different time scales in a non-destructive manner (39).…”