First up this week, guest host Kevin McLean talks to freelance writer Andrew Zaleski about recent advancements in the world of synthetic blood. They discuss some of the failed attempts over the past century that led many to abandon the cause altogether, and a promising new option in the works called ErythroMer that is both shelf stable and can work on any blood type.   Next on the episode, producer Zakiya Whatley talks to Aaron Weimann from the University of Cambridge about the evolutionary history of the deadly bacterial pathogen Pseudomonas aeruginosa. They discuss how more than a century’s worth of samples from all over the world contributed to new insights on the emergence and expansion of the pathogen known for its ability to develop antimicrobial resistance.   This week’s episode was produced with help from Podigy.   About the Science Podcast   Authors: Kevin McLean, Andrew Zaleski, Zakiya Whatley   Episode Page: https://www.science.org/doi/10.1126/science.z1jhbqi   About the Science Podcast: https://www.science.org/content/page/about-science-podcast   [Image: Matt Roth, Music: Jeffrey Cook and Nguyen Khoi Nguyen] Learn more about your ad choices. Visit megaphone.fm/adchoices