Microbial Memory (IMAGE) Rockefeller University Caption CRISPR systems allow bacteria to adapt to new viral threats. Above, Staphylococcus aureus microbes lacking a CRISPR system are killed off by the bacteria-attacking virus ?NM4. This plate approximates the concentration of virus particles used in the recent experiments. Credit Zach Veilleux / The Rockefeller University Usage Restrictions Image may only be used to illustrate research described in the accompanying release. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.