Defined spatial structure stabilizes a synthetic multispecies bacterial community

Abstract

This paper shows that for microbial communities, ''fences make good neighbors.'' Communities of soil microorganisms perform critical functions: controlling climate, enhancing crop production, and remediation of environmental contamination. Microbial communities in the oral cavity and the gut are of high biomedical interest. Understanding and harnessing the function of these communities is difficult: artificial microbial communities in the laboratory become unstable because of ''winner-takes-all'' competition among species. We constructed a community of three different species of wild-type soil bacteria with syntrophic interactions using a microfluidic device to control spatial structure and chemical communication. We found that defined microscale spatial structure is both necessary and sufficient for the stable coexistence of interacting bacterial species in the synthetic community. A mathematical model describes how spatial structure can balance the competition and positive interactions within the community, even when the rates of production and consumption of nutrients by species are mismatched, by exploiting nonlinearities of these processes. These findings provide experimental and modeling evidence for a class of communities that require microscale spatial structure for stability, and these results predict that controlling spatial structure may enable harnessing the function of natural and synthetic multispecies communities in the laboratory.microbial ͉ microscale ͉ model ͉ stability ͉ microfluidic

Microbial mutualism dynamics governed by dose-dependent toxicity of cross-fed nutrients

“…High cross-feeding levels can be detrimental to a mutualism Cross-feeding levels are inherently difficult to measure and yet are hypothesized to be a major determinant of mutualism dynamics and stability (Shou et al, 2007;Kim et al, 2008;Estrela et al, 2012;Hom and Murray, 2014). We therefore used our model to address the effect of NH 4 + -cross-feeding levels on mutualism dynamics.…”

Fungal Morphogenesis

“…The difference in gene expression among cells within a community could be caused by stochastic factors, determinant factors (e.g., age, cell-cycle stage), or a response to the microenvironment created by gradients of signaling molecules and the extracellular matrix (Kerr et al 2002;Kim et al 2008;Shank et al 2011). For instance, stochastic expression of Wor1 determines white-opaque switch in Candida (Zordan et al 2006;Tuch et al 2010;Porman et al 2013), and adhesin Cfl1 in the extracellular matrix stimulates morphogenesis from yeast to hypha in Cryptococcus .…”

Microfluidics for bacterial chemotaxis

“…On the other hand, the scale of microfluidic devices is ideal for application to microbial ecology, and a range of microbial processes has been successfully studied with microfluidics, including quorum sensing [197], chemotaxis [14,70,89], collective dynamics [198], and motility in confined environments [121,199]. Also, spatially structured microfluidic landscapes have recently been applied to the study of metapopulations of single [200] and competing bacterial species [201], and to demonstrate that microscale spatial structure enables coexistence [202]. There are three main advantages to the microfluidic model system: (i) ability to accurately manipulate the spatial landscape; (ii) visualization of microbial dynamics at single-cell resolution; and (iii) effortless data collection through videomicroscopy and automated image analysis.…”