Ned Ruby is a professor at the University of Hawaii at Manoa who pioneered the study of a fascinating bacterial-squid symbiosis. The bacterium Vibrio fischeri colonizes the light organ of the squid Euprymna scolopes and produces light, which helps the squid avoid predation and provides the bacteria a protected place to thrive. Over the course of several decades, Dr. Ruby, along with Dr. Margaret McFall-Ngai, have illuminated the complex and elegant interactions between the bacteria and the squid. Dr. Ruby talks about what a symbiosis is, how V. fischeri can count how many friends are around them through quorum sensing, how they can specifically colonize the squid, and his missed opportunity to have been a professional trumpet player. The MicroCase for listeners to solve is about John Shriek, a retired Marine who becomes ill after a camping trip with his son’s Pathfinder Troop.   Participants: Karl Klose, Ph.D. (UTSA) Ned Ruby, Ph.D. (University of Hawaii at Manoa) Jesus Romo (UTSA)