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Monitoring Intraspecies Competition in a Bacterial Cell Population by Cocultivation of Fluorescently Labelled Strains
Published on: January 18, 2014
Self-sensing in Bacillus subtilis quorum-sensing systems
Tasneem Bareia1, Shaul Pollak1, Avigdor Eldar2
1School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 6997801, Israel.
Abstract:
Bacterial cell-cell signalling, or quorum sensing, is characterized by the secretion and groupwide detection of small diffusible signal molecules called autoinducers. This mechanism allows cells to coordinate their behaviour in a density-dependent manner. A quorum-sensing cell may directly respond to the autoinducers it produces in a cell-autonomous and quorum-independent manner, but the strength of this self-sensing effect and its impact on bacterial physiology are unclear. Here, we explore the existence and impact of self-sensing in the Bacillus subtilis ComQXP and Rap-Phr quorum-sensing systems. By comparing the quorum-sensing response of autoinducer-secreting and non-secreting cells in co-culture, we find that secreting cells consistently show a stronger response than non-secreting cells. Combining genetic and quantitative analyses, we demonstrate this effect to be a direct result of self-sensing and rule out an indirect regulatory effect of the autoinducer production genes on response sensitivity. In addition, self-sensing in the ComQXP system affects persistence to antibiotic treatment. Together, these findings indicate the existence of self-sensing in the two most common designs of quorum-sensing systems of Gram-positive bacteria.
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