Uptake of Exogenous Coenzyme Q by Caenorhabditis elegans

Coenzyme Q (Q) functions as a component of the electron transport chain and as a lipid‐soluble antioxidant. Q can be synthesized de novo in the mitochondria or it can be derived from the diet. Both endogenous and exogenous forms of Q localize to the plasma and organellar membranes in cultured human cells. The current study investigates the ability of C. elegans to uptake Q from the surrounding medium and to transport it to the mitochondria. clk‐1 mutants fed a Q‐less diet arrest at the L2 larval stage and are sterile when grown from eggs. If the clk‐1 worms are allowed to develop to the dauer stage on a Q‐replete diet and are then allowed to recover on the Q‐less diet, they become sterile adults. A water‐soluble formulation of Q made by AQUANOVA® is able to rescue the clk‐1 growth arrest and sterility phenotypes of a Q‐less diet for both the worms developing from eggs and those developing from dauer larvae. However, the same formulation fails to rescue the Q‐less Escherichia coli for growth on succinate. A higher concentration of the AQUANOVA® Q is required to rescue clk‐1 mutants carrying the more severe allele than to rescue those carrying a point mutation. Quantification of Q present in lipid extracts from these animals shows that a significant amount of Q is present in the crude mitochondrial fraction. Future work will investigate the effect of this exogenous Q on the function of the aerobic electron transport complexes. This work was supported by NIA Grant AG19777 and by the Ellison Medical Foundation.