Identification of [Arg(7)] corazonin in the silkworm, Bombyx mori and the cricket, Gryllus bimaculatus, as a factor inducing dark color in an albino strain of the locust, Locusta migratoria

The neuropeptides inducing dark color in albino nymphs of the migratory loc ust Locusta migratoria were isolated from the larval brain of the silkworm, Bombyx mori and from the adult corpora cardiaca (CC) of the cricket Gryllu s bimaculatus, respectively, and their amino acid sequences identified. The two peptides isolated from the two different species are identical to [Arg (7)] corazonin, a neuropeptide known to be present in a cockroach and other s. This peptide induces a dark color in albino nymphs of L. migratoria at f mol levels, and a high dose of greater than or equal to 100 pmol caused alb ino locusts to turn completely black, but it influenced neither body color nor metamorphosis in B. mori and G. bimaculatus. Therefore, the physiologic al functions of [Arg(7)] corazonin in the silkworm and the cricket remain u nknown. The present study demonstrated the usefulness of the albino strain of L. mirgatoria as a specific bioassay system for this peptide. (C) 2000 E lsevier Science Ltd. All rights reserved.