Nature, Published online: 22 July 2026; doi:10.1038/s41586-026-10833-9

CRISPR–Cas systems transcriptionally tune diverse innate defences using CRISPR RNA-like guides to balance antiviral protection with fitness, and hyperactivate these defences when compromised, establishing a layered bacterial ‘immunity guard’ network.

Nature, Published online: 15 July 2026; doi:10.1038/s41586-026-10804-0

Elastic instabilities in mechanical metamaterials can be harnessed to programme fracture behaviour, transforming instability from a failure mechanism into a design principle that increases fracture energy by up to tenfold.