COMPARATIVE ASPECTS OF ENERGY-METABOLISM IN PLANT TRYPANOSOMATIDS

The energy metabolism was compared among four different representative s of the genus Phytomonas isolated from different plants and localitie s: the sieve tubes of the hartrot-infected coconut palm in French Guya na, the latex fluid of Euphorbia hyssopifolia in French Guyana and the fruits of tomato and cherimoya in Spain. All four isolates produced a cetate, ethanol, glycerol and glycine as metabolic end-products. In ad dition, small amounts of succinate and pyruvate were excreted. Only mi nor quantitative differences were observed in the four isolates. Glyco somes, harboring the glycolytic enzymes, were present in all isolates. No evidence was found for an active involvement of the mitochondrion in metabolism. Respiration was insensitive to the classical inhibitors of the respiratory chain, such as antimycin and potassium cyanide, bu t inhibited by salicylhydroxamic acid. No evidence was found for the f unctioning of a citric-acid cycle. It is concluded that representative s of this genus share the same highly active carbohydrate metabolism c ombined with a complete suppression of mitochondrial activity.