Reviews & Analysis

Plasmonic hotspots — nanometre-sized crevices that permit the detection of single molecules — are too small to be imaged with conventional microscopes. They can now be probed using super-resolution fluorescence microscopy. See Letter p.385

Social slime moulds graze on bacteria, but save some for transmission in their spores. Strains practising this primitive form of farming coexist with non-farmer strains in an intriguing cost–benefit equilibrium. See Letter p.393

The transformation of tadpole to frog and of caterpillar to butterfly are two of the more obvious examples of metamorphosis. But molecular shape-shifting may occur in each of us as part of our innate antibacterial defence system. See Letter p.419

A growing body of literature deals with the application of theories developed in other disciplines to financial institutions, to which a paper in this issue now adds. As outlined here, however, views differ as to its relevance. See Perspective p.351

The resting brain recapitulates activity patterns that occurred during a recent experience, possibly to aid long-term memory formation. Surprisingly, corresponding brain activity also occurs before an event happens. See Letter p.397

The massive compact objects in the centres of galaxies developed in at least two ways. One seems to be a natural result of galaxy formation in the Big Bang theory of the expanding Universe — the other is enigmatic. See Letters p.374 & p.377

Two human trials investigate the efficacy of a type of antiretroviral drug — usually used to treat HIV-infected individuals — in preventing HIV infection. The results are heartening.

Protein engineering of an enzyme that catalytically detoxifies organophosphate compounds in the body opens up fresh opportunities in the search for therapeutic protection against nerve agents used in chemical warfare.

Cellular compartmentalization is an effective way to build gene circuits capable of complex logic operations, in which binary inputs are converted into binary outputs according to user-defined rules. See Letters p.207 & p.212

G-protein-coupled receptors initiate a wide range of signalling pathways in cells. It seems that both a G protein and an agonist molecule must bind to the receptors to persistently activate them. See Article p.175 & Letters p.236 & p.241

A survey of bumblebees in North America provides unequivocal evidence that four previously common and abundant species have undergone recent and widespread population collapse. Various explanations remain possible.

Studies of animal populations often use tags to track the fate of individuals and assume that there is no adverse impact. Work on penguins shows that seemingly innocuous flipper bands affect survival and breeding success. See Letter p.203

Generations of physicists have spent much of their lives using Richard Feynman's famous diagrams to calculate how particles interact. New mathematical tools are simplifying the results and suggesting improved underlying principles.

The functions of proteins are critically coupled to their interplay with water, but determining the dynamics of most water molecules at protein surfaces hasn't been possible. A new spectroscopic method promises to change that.

The Eastern Lau spreading centre in the Pacific Ocean is the subject of especial interest. The influence of the neighbouring subduction zone is considerable, but evidently has unexpected limits. See Letter p.198