Microbial cells stained green. (IMAGE) University of Tokyo Caption This picture shows many tiny cells in which DNA is abundantly included inside the cells. First, the microbial cells were detected in fractures in the rock sample using an infrared imaging technique called O-PTIR spectroscopy. After that, they were stained with a green solution and analyzed using both a scanning electron microscope and then fluorescent microscopy. The combination of readings from these three imaging techniques enabled the researchers to confirm the indigenous and living microbial cells in the 2-billion-year-old rock fissure. Credit Y. Suzuki, S. J. Webb, M. Kouduka et al. 2024/ Microbial Ecology Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. No derivatives or adaptations of the work are permitted. License CC BY-NC-ND 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.