Do all bacteria use the same signal molecules?

Different bacterial species use different molecules to communicate. There are several different classes of signalling molecule (see examples). Within each class there are also minor variations such as length of side chains etc. In some cases a single bacterial species can have more than one QS system and therefore use more than one signal molecule. The bacterium may respond to each molecule in a different way. In this sense the signal molecules can be thought of as words within a language, each having a different meaning.

Can bacteria from one species communicate with those from another species?

There is evidence that interspecies communication via QS can occur. This is referred to as quorum sensing cross talk. Cross talk has implications in many areas of microbiology as in nature bacteria almost always exist in mixed species populations such as biofilms.

What are the benefits of quorum sensing research?

QS research has many potential applications, most of these involve controlling bacteria by interfering with their signalling systems. For example many bacteria rely on QS to control the expression of the genes which cause disease. If we can block the QS systems we may be able to prevent these bacteria from being dangerous.