Offense or defense? Quorum sensing has been tied to a number of bacterial functions, many of them involving virulence, but could quorum sensing also be used in defense? In mBio this week, there's new evidence that E. coli uses quorum sensing to trigger an antiphage mechanism that defends against at least two very different types of phage.
In evading phages, timing is everything. There are any number of ways for a bacterium to defend itself, but the benefits of evading an attack have to be weighed against the metabolic costs or readiness, so it makes sense to set up defenses only when they're needed. Since phages are thought to be more abundant and diverse in densely-populated environments with many different bacterial species, the authors reasoned that it would make sense for a bacterium to detect these conditions and turn on antiphage defenses on an as-needed basis.
Click on teh "source" link to read more on mBio's blog, mBiosphere.