Patterning of mutually interacting bacterial bodies: close contacts and airborne signals

Jaroslav J Čepl,Anna Blahůšková,Irena Pátková,Fatima Cvrčková,Anton Markoš

doi:10.1186/1471-2180-10-139

Abstract

BackgroundBacterial bodies (colonies) can develop complex patterns of color and structure. These patterns may arise as a result of both colony-autonomous developmental and regulatory processes (self-patterning) and environmental influences, including those generated by neighbor bodies. We have studied the interplay of intra-colony signaling (self-patterning) and inter-colony influences in related clones of Serratia rubidaea grown on rich media.ResultsColonies are shaped by both autonomous patterning and by signals generated by co-habitants of the morphogenetic space, mediating both internal shaping of the body, and communication between bodies sharing the same living space. The result of development is affected by the overall distribution of neighbors in the dish. The neighbors' presence is communicated via at least two putative signals, while additional signals may be involved in generating some unusual patterns observed upon encounters of different clones. A formal model accounting for some aspects of colony morphogenesis and inter-colony interactions is proposed.ConclusionsThe complex patterns of color and texture observed in Serratia rubidaea colonies may be based on at least two signals produced by cells, one of them diffusing through the substrate (agar) and the other carried by a volatile compound and absorbed into the substrate. Differences between clones with regard to the interpretation of signals may result from different sensitivity to signal threshold(s).

Highlights

Bacterial bodies can develop complex patterns of color and structure
Bacteria can display a plethora of multicellular forms; their structure and appearance depends on factors such as the presence of nutrients or neighbors
Bacterial populations react to such signals - and build multispecies bodies - in a context-dependent

Summary

Introduction

Bacterial bodies (colonies) can develop complex patterns of color and structure. These patterns may arise as a result of both colony-autonomous developmental and regulatory processes (self-patterning) and environmental influences, including those generated by neighbor bodies. To create and maintain such elaborated structures, a great deal of communication, regulations, mutual understanding, and cooperation takes place in bacterial morphogenesis. Differentiation in such a bacterial body (as a body, not a population of cells) may proceed via genetically differing subclones fulfilling different roles, and appearing reproducibly at characteristic periods of cultivation [7,8,9,10]. Sophisticated networks of chemical signals [11,12,13], the scaffolding of extracellular matrix [14] and even cell-to-cell contacts [15,16] may enable attaining and maintaining the integrity of the body Research in this direction has been greatly accelerated in last two decades by the discovery of the phenomenon of quorum sensing (see [17,18,19]; for Serratia see [13]). Bacterial populations react to such signals - and build multispecies bodies - in a context-dependent

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