Pili in the Bacterium Caulobacter crescentus (image) Indiana University Share Print E-Mail Caption This image shows pili (green) in cells from the bacterium Caulobacter crescentus (orange). IU scientists used a fluorescent maleimide molecule to stain pilin proteins that contained a cysteine molecule, which was introduced in place of one of the pili's amino acids. Credit Courtney Ellison, Indiana University Usage Restrictions Credit Courtney Ellison, Indiana University Share Print E-Mail 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.