Bioactive natural compounds obtained from arthropods

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1) Volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] is known as an insect-produced plant volatiles elicitor. In this study, the in vitro biosynthesis of volicitin was demonstrated for the first time by using gut tissues of Spodoptera litura larvae. The absolute configuration of the hydroxylinolenoyl moiety of volicitin was determined to 17-S in high enantiomeric excess in S.litura. Furthermore, N-linolenoyl-L-glutamine was only about 30% as active as volicitin. Among synthesized volicitin-related compounds, only glutamine conjugate induced the emission of volatile compounds from corn seedlings. On the other hand, we found uktraweak phton emissions from maize leaves damaged by Heilcovera armigera. Interestingly, the direct interaction between maize leaf cells and chemicals obtained from caterpillar regurgitants triggers the phton emissions.2) Pumiliotoxins are very widely distributed in alkaloids-containing anurans from the neotropics. We demonstrated pumiliotoxin 237A, 251D and 8-deoxypumiliotoxin 193H from oribated mite extracts. It appears possible that some of the pumiliotoxins and related congeners found in extracts of various anurans have amite origin3) Some particular substances obtained from mites, such as secretions from opisthonothal glands are suspected as one of antigens. We happened to find α-acaridial showed a positive reaction in patch tests for atopic dermatitis patients. In this study, we demonstrated that the female sex pheromone of Rhizoglyphus setosus (Astigmata : Acaridae) was identified as S-robinal, which is analogous to α-acaridial. Furthermore, we established the species-specific ITS sequence useful for the species identification of astigmatid mites and for studying low-level phylogenetic relationships.