Known as the cellular powerhouse, mitochondria are responsible for production of energy to fuel various cellular processes.   Jeffrey A. Butler, from the University of Texas Health Science Center at San Antonio (Texas, USA), and colleagues have successfully activated life extension in the roundworm C. elegans, and in the process discovered a new metabolic state correlating with long life.  The team compared one class of long-lived C. elegans, called the Mit mutants (which have disrupted mitochondrial electron transport chain functionality), with non-mutant wild type C. elegans.  They found significant metabolism changes, suggesting that their cellular engines had been reconfigured to run on new fuels and to make new waste products, leading to increased lifespans.  Writing that: “Our study suggests long-lived, genetically specified Mit mutants employ a novel metabolism,” the team concludes that: ”Life span may well arise as a function of metabolic state.”