Whole insect assays

Unknown Another use of this sort of system is in the identification of compounds from natural sources where there is often such a small quantity of compound available that you would never see activity in more traditional whole animal or insect assays. The test system doesn t have to be a single receptor or enzyme. The kind of thing I have in mind is that we would never have discovered one of our antibiotics if we had not had a bacterial cell wall assay. The fermentation mixture itself has no antibacterial activity. 

Fig. 25.1.1. Chemical structures of 20-hydroxyecdysone (20E 1 R] = OH), the first bisacylhydrazine found to have an ecdysone agonist effect in insect assays (2), and the first bisacylhydrazine (RH-5849 3) well characterized for its ecdysone effects at cellular and whole insect level, as well as binding to Drosophila melanogaster ceW extracts containing ecdysteroid receptor complexes. Numbers on the 20E structure represent the carbon-numbering system.

Unknown When you assay compounds that are active in some in vitro system and they are inactive in vivo, how often do you assay those insects to determine if the enzyme or receptor was, in fact, affected in the whole animal ... 

The (myo) kinin family of peptides is especially a very interesting one, because its members have two very different functional activities in insects. The first members of this family were originally isolated on the basis of stimulation of the cockroach hindgut in vitro from extracts of whole heads of L. maderae [151]. This species contains 8 isoforms of kinins. Shortly after their first isolation, it was reported that these kinins also stimulate diuretic activity of isolated Malpighian tubules of the yellow fever mosquito Aedes aegypti [175], This function of kinins has now been shown regularly in conspecific diuretic assays with a number of other insect species. To date, the structure of kinins (see Table 5) have been fully elucidated in insects from the American cockroach (8 isoforms), the house cricket, Acheta domesticus (5 isoforms), the migratory locust (1 isoform), the mosquitoes, Culex salinarius and A. 

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