Summary
Bacteria release and detect signalling molecules to coordinate behaviour as population density rises.
In depth
Cells secrete autoinducers (acyl-homoserine lactones in Gram-negatives, peptides in Gram-positives); when the concentration crosses a threshold, genes switch on. First found in Vibrio fischeri's bioluminescence in squid. It controls virulence and biofilms.
Quorum quenching is an anti-virulence idea.
Quorum sensing allows population-level behaviours such as biofilm formation and virulence factor production. Inhibitors may be used as anti-infective strategies.
Remember: it was found in bioluminescent bacteria.
Discovered in Vibrio fischeri, which makes light in the Hawaiian bobtail squid only when dense. Autoinducers diffuse out and accumulate, and when they bind receptors they activate genes. Processes controlled include virulence, biofilm formation, sporulation, antibiotic production, competence and bioluminescence. AI-2 is a signal used between species.
Quorum quenching blocks signalling with enzymes or analogues, offering anti-virulence strategies that put less pressure for resistance than antibiotics. Plants also make compounds that mimic signals. The concept shows that bacteria behave as coordinated groups.
Remember: the signal indicates the density of cells, as well as diffusion limits in the environment.
Frequently asked questions
What is Quorum Sensing?
Bacteria release and detect signalling molecules to coordinate behaviour as population density rises.
Which area of biology covers Quorum Sensing, and how advanced is it?
Quorum Sensing is one of the 54 topics in Microbiology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Two-Component Systems, Biofilms, Antibiotics.
What should I learn before Quorum Sensing?
Work through the Beginner topics in Microbiology first, such as Microorganisms, Bacteria, Archaea, then return to Quorum Sensing. Advanced topics assume the Intermediate vocabulary.
What topics are related to Quorum Sensing?
The closest topics to Quorum Sensing are Two-Component Systems, Biofilms, Antibiotics, Horizontal Resistance Spread. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Quorum Sensing?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Quorum Sensing. To practise the whole of Microbiology, use the Microbiology quiz.
How is Quorum Sensing different from Two-Component Systems?
Quorum Sensing: Bacteria release and detect signalling molecules to coordinate behaviour as population density rises. Two-Component Systems: Sensor kinase and response regulator pairs that let bacteria sense and respond to environmental changes. Read both side by side and note what each one explains.
How should I study Quorum Sensing step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Two-Component Systems and explain the difference aloud. Finally, take the Microbiology quiz and come back to this page for any question you miss.