Image 2 (IMAGE) Nanyang Technological University Caption Microscopic images of the amount of enzyme activity (dark purple specks) in the mitochondria in the muscle of mice. When microbes were transplanted into germ-free mice, enzyme activity increased, which translates to a higher capacity for the muscle to produce energy. L-R: Muscle of standard laboratory mice, Muscle of germ-free mice, Muscle of germ-free mice transplanted with gut microbes from lab mice. Credit NTU Singapore Usage Restrictions Use with mandatory credit 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.