Microbiology: Gut defence The severity of salmonella infections depends in part on how effectively the invaders are destroyed. Incisive experiments now show that host defence in the intestine centres on the aptly named defensins

Cell motility: Making streams Cells of the slime mould Dictyostelium discoideum can move in a kind of close-order drill. New evidence suggests that they do this by secreting a chemical attractant specifically from them rear, luring the cells that follow

Nuclear physics: Into the fission valley Why are new elements difficult to make? Fusion of two nuclei to produce heavy elements seems to be hindered by a competing process of 'quasi-fission'. New work builds a more complete picture