Really fascinating, thanks for posting.
Ah, those modern bacteria, with their long cilia and their music.
In a few years they will be bald and will have a single flagellum as a pony tail.
This is probably quibbling, but I object strongly to this kind of language. The language implies that the bacteria somehow choose how to evolve. In reality, they do no such thing.
Evolution is a force that acts upon living organisms. The DNA is constantly mutating at random, and those mutations do not have much effect in a static environment--the "bad" mutations do not persist, the "good" mutations tend to spread through the population, and the "neutral" mutations may or may not persist since they (neutral changes) have no effect on the organism.
While this article implies that the bacteria used different strategies to overcome the introduction of a less than optimal EF-Tu, in reality, due to the random nature of mutation, some of the bacteria happened to have mutations in the regulatory regions of the EF-Tu gene, causing them to make more of it, which would overcome the effects of decreased binding affinity. Other bacteria happened to have mutations in the coding regions of other proteins that work with EF-Tu that caused those proteins to interact better with the EF-Tu.
All of the "adaptive" changes were random. The bacteria chose none of them.
Sorry about the long post and heavy use of technical language. It's just that this idea that organisms guide their own evolution really irks me, since evolution is not guided by anything other than physical forces.