Carnegie Mellon University biologists have discovered that Vibrio cholerae, the bacteria behind the cholera disease, can sense when its relatives die. Bacterial cell death is often accompanied by lysis, where the cell explodes, releasing internal cellular components. The researchers found that a small molecule released during cell lysis is detected by living V. cholerae, which drives the survivors to clump together and form large communities, known as biofilms, to protect themselves.