Microbes can exert both positive and negative effects on animal health and longevity. The nematode worm, Caenorhabditis elegans, and its bacterial diet, Escherichia. coli, provide a simplified model to study animal-microbe interactions. Inhibiting E. coli folate synthesis has been found to increase C. elegans lifespan without any negative effects on either organism. Specifically disrupting worm folate uptake or metabolism was not found to influence lifespan and it was therefore hypothesized that a folate-dependent bacterial activity modulates ageing. This thesis aims to understand the factors that influence bacterial folate synthesis with the ultimate aim of understanding how bacterial folate affects C. elegans ageing
