title: Bacterial social interactions drive the emergence of differential spatial colony structures.
abstract: BACKGROUND
  Social interactions have been increasingly recognized as one of the major factors that contribute to the dynamics and function of bacterial communities. To understand their functional roles and enable the design of robust synthetic consortia, one fundamental step is to determine the relationship between the social interactions of individuals and the spatiotemporal structures of communities.
  
  
  RESULTS
  We present a systematic computational survey on this relationship for two-species communities by developing and utilizing a hybrid computational framework that combines discrete element techniques with reaction-diffusion equations. We found that deleterious interactions cause an increased variance in relative abundance, a drastic decrease in surviving lineages, and a rough expanding front. In contrast, beneficial interactions contribute to a reduced variance in relative abundance, an enhancement in lineage number, and a smooth expanding front. We also found that mutualism promotes spatial homogeneity and population robustness while competition increases spatial segregation and population fluctuations. To examine the generality of these findings, a large set of initial conditions with varying density and species abundance was tested and analyzed. In addition, a simplified mathematical model was developed to provide an analytical interpretation of the findings.
  
  
  CONCLUSIONS
  This work advances our fundamental understanding of bacterial social interactions and population structures and, simultaneously, benefits synthetic biology for facilitated engineering of artificial microbial consortia.
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, 61801, USA. blnchrd2@illinois.edu.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Blanchard
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, 61801, USA. luting@illinois.edu.|Department of Bioengineering, University of Illinois at Urbana-Champaign, 1304 West Springfield Avenue, Urbana, 61801, USA. luting@illinois.edu.|Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, 61801, USA. luting@illinois.edu.
authors.forename: Ting
authors.initials: T
authors.lastname: Lu
mesh_terms: D001419:Bacteria / Q000166:cytology / Q000254:growth & development; D019295:Computational Biology / Q000379:methods*; D056265:Microbial Interactions; D008954:Models, Biological; D062211:Spatio-Temporal Analysis