Related Experiment Video
Updated: Mar 27, 2026
06:26
Time-lapse Imaging of Bacterial Swarms and the Collective Stress Response
Published on: May 23, 2020
9.0K
Quorum sensing protects bacterial co-operation from exploitation by cheats
Richard C Allen1, Luke McNally1, Roman Popat1
1Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
The ISME Journal
|January 9, 2016
Summary
Bacteria use quorum sensing (QS) to communicate and invest in cooperation only when surrounded by other cooperators. This bacterial social behavior, similar to generalized reciprocity in vertebrates, maintains cooperation in structured populations.
Area of Science:
- Microbiology
- Evolutionary Biology
- Behavioral Ecology
Background:
- Quorum sensing (QS) is a cell-cell communication system in bacteria.
- QS regulates cooperative traits, such as extracellular enzyme production.
- Bacterial cooperation is vulnerable to exploitation by non-cooperative 'cheats'.
Purpose of the Study:
- To investigate how bacterial quorum sensing (QS) regulates cooperation based on population genotypic composition.
- To determine if QS allows bacteria to sense and respond to the frequency of cooperators versus cheats.
- To explore the evolutionary maintenance of bacterial cooperation through social sensing.
Main Methods:
- Mathematical modeling of bacterial social behavior.
- Experimental analysis using high-density populations of Pseudomonas aeruginosa.
- Quantification of per-capita signal production and cooperative enzyme investment.
Main Results:
- The canonical QS architecture enables bacteria to assess the proportion of cooperators in a population.
- Bacteria limit investment in cooperation when non-responder cheats are frequent.
- A 'cooperate when surrounded by cooperators' strategy was observed, matching investment to group composition.
Conclusions:
- Bacterial quorum sensing facilitates conditional cooperation, akin to generalized reciprocity in vertebrates.
- This mechanism allows for the maintenance of cooperation even at lower levels of population relatedness.
- Reciprocity mechanisms can be implemented at the cellular level through feedback circuits, independent of advanced cognition.
Related Concept Videos
01:30Bacterial Signaling
43.1K
Bacterial signaling can occur within bacteria (intracellular) or between bacteria (intercellular). At times, a group of bacteria behaves like a community. To achieve this, they engage in quorum sensing, the perception of higher cell density that causes changes in gene expression. Quorum sensing involves both extracellular and intracellular signaling. The signaling cascade starts with a molecule called an autoinducer (AI). Individual bacteria produce AIs that move out of the bacterial cell...
43.1K
01:28Gene Regulation in Microbial Communities: Quorum Sensing
873
Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
873
01:26Microbial Interactions: Cooperation
36
Microbial cooperation involves beneficial interactions in which different species work together for individual or mutual advantage. These interactions can profoundly influence ecological dynamics and evolutionary processes, and they are essential to many pathogenic and symbiotic relationships.Nematode–Bacteria CooperationA striking example is the relationship between the Gram-negative bacterium Xenorhabdus nematophila and the parasitic nematode Steinernema carpocapsae. Juvenile nematodes...
36
01:29Coordination of Gene Expression Processes in Bacteria
886
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
886
01:23Stringent Response in E. coli
466
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
466
01:28Regulation of Bacterial Virulence
17
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
17