Fig. (1) Mutants affected in genes encoding ETF and ETF-dH display higher growth rate on non-fermentable carbon sources. Cells of the parental strain (BY4741) and of mutants affected in AIM45 (aim45), YGR207c/CIR1 (cir1) and YOR356w/CIR2 (cir2) were grown overnight and diluted to OD₆₀₀=1. From this suspension, 3µL of 10^-1-10^-5 dilutions were spotted on rich media containing glucose (YPD), acetate (YPAcet), fumarate (YPFum), ethanol (YPEth), lactate (YPLact), succinate (YPSucc), pyruvate (YPPyr), malate (YPMal) or methanol (YPMeth) as sole carbon source. After 48h incubation at 30ºC, plates were photographed. Photographs represent typical results from at least three independent experiments.