Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
CRISPR systems, which are composed of direct repeats that are separated by similarly sized non-repetitive spacers, confer resistance to phages in many bacteria and most archaea. This new antiviral tactic is thought to involve an RNA-interference-like mechanism, and is reviewed in this Progress article.
Shigellause a type III secretion system to deliver effector proteins into the host-cell cytoplasm, where they can usurp host-cell functions and signalling pathways. In this Progress article, Chihiro Sasakawa and colleagues highlight the most recent advances in our understanding of the exact functions of the manyShigellatype III-secreted effectors.