Biofilms: Microbial Cities Wherein Flow Shapes Competition
An interesting "Spotlight" in Trends in Microbiology published online last week.
A very nice mini-review or "spotlight article" has just be published explaining how flow can shape competitive interactions within the biofilm.
The title is very catchy and drew me in before I realised that the authors actually come from Nanyang and SCELSE who are the partners for npj Biofilms and Microbiomes.
In their "spotlight", Su Chuen Chew and Liang Yang highlight a recent wave of research that asks how selection and evolution of strains within a biofilm are affected by flowing liquid. They use the example of "cheaters" which, from a microbiological standpoint are populations of cells that do not contribute to the survival of the biofilm colony but take advantage of the "public goods" that are made available by other cells. Cheaters are bad news and while a few can be supported, if you get too many cheaters in your biofilm then quickly, your colony will no longer be able to support itself and everyone will die. As such, there are many evolutionary mechanisms to keep cheaters in check, and some of them are discussed in this article.
The phenotypic diversity in biofilms allows bacteria to adapt to changing environmental conditions. Stochastic gene expression and structural differentiation are believed to confer phenotypic diversity. However, two recent publications demonstrate how hydrodynamic flow and substrate topography can also alter the competitive outcomes of different bacterial phenotypes, increasing biofilm phenotypic variation.
Su Chuen Chew, Liang Yang, Biofilms: Microbial Cities Wherein Flow Shapes Competition, Trends in Microbiology, Available online 1 March 2017, ISSN 0966-842X, http://dx.doi.org/10.1016/j.tim.2017.02.007.