MACs Array (IMAGE) San Diego State University Caption 'Death Star' bacterial syringe structure -- Metamorphosis Associated Contractile structures (MACs) discovered by SDSU marine microbiologist Nicholas Shikuma and his lab team. It injects a protein into animal cells that leads to metamorphosis, it may also be in the human gut,and could be tapped to deliver targeted drugs in the future. Credit Shikuma Lab Usage Restrictions None 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.