LIPID BIOSYNTHESIS IN THE BOLL WEEVIL: FORMATION OF THE ACETATE PRECURSOR FOR LIPID SYNTHESIS FROM GLUCOSE AND RELATED CARBOHYDRATES

Abstract

Glucose, sucrose, fructose, and their related glycolytic products, pyruvate and acetate, were readily converted into long-chain fatty acids by larval and adult boll weevils (Anthonomus grandis Boheman, Coleoptera:Curculionidae). By comparison of the radiorespirometric formation of14CO2of adults injected with differentially labeled glucose and pyruvate to the specific activity of lipid synthesized from these substrates, it was determined that glycolysis is the principal pathway by which acetate is produced. The patterns suggested that the boll weevil possesses the pentose phosphate pathway, which also accounts for a significant oxidation of glucose. Recombinations of labeled carbon atoms within and between intermediates of the pentose cycle allow synthesis of labeled fatty acid to take place with those carbons of glucose which could not ordinarily enter fat synthesis by glycolysis alone.