BIOSYNTHESIS OF TAURINE IN TISSUES OF THE LOCUST (SCHISTOCERCA-AMERICANA-GREGARIA) AND THE EFFECT OF PHYSIOLOGICAL AND TOXICOLOGICAL STRESSES ON BIOSYNTHETIC RATE OF THIS AMINO-ACID

The biosynthesis of the amino acid taurine has been studied in the loc ust Schistocerca americana gregaria. Tissue concentrations of putative precursors of taurine, and taurine itself were estimated in haemolymp h, nervous tissue and muscle. Following this locusts were injected wit h 20 mu Ci of [S-35]cysteine and tissue samples were taken at times th ereafter, and taurine and its precursors were extracted and separated by thin-layer chromatography (TLC). Taurine, cysteine sulphinic acid ( CSA) were quantified by scintillation counting, Cysteic acid and hypot aurine were qualitatively detected by autoradiography of TLC plates. R esults indicate that in haemolymph and muscle the biosynthetic pathway for taurine is cysteine then CSA, cysteic acid and thereafter taurine . In nervous tissue both cysteic acid and hypotaurine were detected su ggesting two possible pathways for taurine since both are immediate pr ecursors of this amino acid. Taurine biosynthesis was markedly greater in juvenile compared with mature adult locusts. It was also observed that picrotoxin treatment and prolonged flying, which have both previo usly been found to cause a redistribution of taurine in the locust, in creased the biosynthesis of this amino acid.