Bacterial cultures that can count up to three

In a recent issue of Science, Friedland et al. report bacterial cultures that can count up to 3 - albeit without knowing it themselves. What they count are pulses of arabinose, a sugar - and they report via fluorescence signal.

Journal club 15/6/2009

In their paper "Chaperonin overexpression promotes genetic variation and enzyme evolution", Tokuriki and Tawfik show protein stability is a major constraint in protein evolution. Chaperonin over-expression can, at least partially, mitigate it, see Nature 459, 668-673. In the same issue of Nature, Mueller et al. present the structure of an alpha-helical toxin pore and propose a detailed mechanism for pore-formation, see pages 726-730.