Worms without Duox (left) are translucent and often burst.
Protein cross-linking by radical reactions is normally associated with aging-related tissue damage, but on page 879 Edens et al. report that worms specifically use cross-linking of collagen to make a strong cuticle. Without the combined oxidase/peroxidase that does the cross-linking, the cuticle separates into distinct layers, resulting in translucent worms that often suffer from massive blisters and defective movement.
The clue that the cross-linking enzyme (called Duox for Dual Oxidase) might exist came from studies of phagocyte NADPH-oxidase. The latter enzyme generates bursts of superoxide to effect killing of engulfed cells. But other cell types, some of which lack phagocyte NADPH-oxidase, generate lower levels of reactive oxygen species.
Duox may be one of the sources of this oxidative activity. Edens et al. isolated genes for human and worm Duox enzymes based on similarity to phagocyte NADPH-oxidase,...
