PURIFICATION OF TOXIC COMPOUNDS FROM LARVAE OF THE GRAY FLESHFLY - THE IDENTIFICATION OF PARALYSINS

Larval haemolymph of Neobellieria bullata (Insecta, Diptera) is highly toxic to adults of the same species: injection causes instant paralys is to death. Referring to their dramatic effect in adult insects the r esponsible compounds were designated paralysins. Two paralysins, solub le in organic solvents and heat stable, were chromatographically purif ied to homogeneity. They were identified by use of mass spectrometry a nd nuclear magnetic resonance respectively as beta-alanine-tyrosine (b eta-Ala-Tyr) and as 3-hydroxy-kynurenine (3-HK). The quantities of bet a-Ala-Tyr and 3-HK in the insect appear to increase steadily during la rval development, with peak values prior to the pupal stage. These fin dings may contribute to a better understanding of some aspects of the process of insect metamorphosis. Orienting experiments in mammals sugg est that both compounds, when injected intraspinally, are also neuroto xic to rats. In addition, cytotoxicity tests revealed that 3-HK, but n ot beta-Ala-Tyr is toxic to human neuroblastoma cells, rat primary cor tex neurons as well as to rat glial cells. (C) 1998 Academic Press.