Deadly competition between sibling bacterial colonies

Avraham Be'er, H. P. Zhang, E. L. Florin, Shelley M. Payne, Eshel Ben-Jacob, Harry L. Swinney

Research output: Contribution to journalArticlepeer-review

72 Scopus citations


Bacteria can secrete a wide array of antibacterial compounds when competing with other bacteria for the same resources. Some of these compounds, such as bacteriocins, can affect bacteria of similar or closely related strains. In some cases, these secretions have been found to kill sibling cells that belong to the same colony. Here, we present experimental observations of competition between 2 sibling colonies of Paenibacillus dendritiformis grown on a low-nutrient agar gel. We find that neighboring colonies (growing from droplet inoculation) mutually inhibit growth through secretions that become lethal if the level exceeds a well-defined threshold. In contrast, within a single colony developing from a droplet inoculation, no growth inhibition is observed. However, growth inhibition and cell death are observed if material extracted from the agar between 2 growing colonies is introduced outside a growing single colony. To interpret the observations, we devised a simple mathematical model for the secretion of an antibacterial compound. Simulations of this model illustrate how secretions from neighboring colonies can be deadly, whereas secretions from a single colony growing from a droplet are not.

Original languageEnglish
Pages (from-to)428-433
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number2
StatePublished - 13 Jan 2009
Externally publishedYes


  • Bacterial competition
  • Bacterial growth
  • Growth inhibition
  • Paenibacillus dendritiformis


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