Shogo Matsumoto

The structure of allosamidin, a novel insect chitinase inhibitor, produced by Streptomyces Sp.

Allosamidin(1), a novel insect chitinase inhibitor, was isolated from the mycelium of Streptomyces sp. and characterized as 1, which was a basic pseudotrisaccharide consisting of 2-acetamido-2-deoxy-D-allose(N-acetyl-D-allosamine) and a novel aminocyclitol derivative(3), termed allosamizoline.

Isolation and primary structure of neuropeptides from the mosquito, Aedes aegypti, immunoreactive to FMRFamide antiserum

Abstract Two novel neuropeptides, Aea-HP-I and II, have been isolated from a head extract of the mosquito, Aedes aegypti; they were detected by a FMRFamide radioimmunoassay. The peptides were purified by gel filtration, ion exchange chromatography, and reversed-phase high performance liquid chromatography. Amino acid composition and sequence analysis, combined with enzymatic digestion, established the primary structure of Aea-HP-I as pGlu-Arg-Pro-Hyp-Ser-Leu-Lys-Thr-Arg-Phe-NH2 and Aea-HP-II as Thr-Arg-Phe-NH2. Aea-HP-I was synthesized, and chromatographic properties of the synthetic peptide were the same as those of the native peptide, thus confirming the structural analysis. The peptide has three unusual residues: an amino-terminal pGlu, a Hyp in the fourth position, and a carboxyl-terminal amide. The Pro-Hyp sequence occurs in toxin peptides from the venoms of cone snails and wasps and in bradykinin analogues. Although the functions of Aea-HP-I and II have not been determined, the peptides have the same RFa sequence at the carboxyl-terminal as Lem-SK-I and II (leucosulfakinins) and Lem-MS (leucomyosuppressin) in cockroaches and FMRFamide-related peptides in molluscs.

Purification and properties of the melanization and reddish colouration hormone (MRCH) in the armyworm, Leucania separata (Lepidoptera)

Larvae of Leucania separata show a marked black colouration under crowded conditions due to the action of the neurohormone termed melanization and reddish colouration hormone (MRCH). MRCH was extracted with 80% ethanol from larval brains (Br) or suboesophageal ganglia (SG) of L. separata and Br-SG of the silkworm moth, Bombyx mori. Approximately a 16,300-fold purification of the extract derived from 192,000 Bombyx heads afforded two active fractions, each of which caused a remarkable melanization of the cuticle of an L. separata larva. The MRCH activity contained in each fraction is due to a peptide (mol. wt. 6400–8000). Partially purified MRCH also caused melanization in Leucania loreyi, Spodoptera litura, and Mamestra brassicae, but had no diapause hormone activity in B. mori.

Control of ommochrome synthesis by both juvenile hormone and melanization hormone in the cabbage armyworm,Mamestra brassicae

SummaryPigmentation of last instar larvae of the cabbage armyworm,Mamestra brassicae is of two types: melanin in the cuticle and ommochrome in the epidermis. The latter was found to be primarily xanthommatin. When allatectomy was performed 8 h before head capsule slippage (HCS) in the last larval molt, later ommochrome synthesis was inhibited. Application of juvenile hormone (JH) up to 12 h after HCS (9 h before ecdysis) (activity: methoprene≧JH I>JH II>JH III) restored ommochrome synthesis. After that time it has less and less effect.Removal of the suboesophageal ganglion from the larvae 8 h before HCS prevented both later ommochrome synthesis and melanization. Melanization of isolated abdomens was restored by implantation of 3 suboesophageal ganglia or injection of melanization and reddish coloration hormone (MRCH) 18 h after HCS. Restoration of ommochrome synthesis required exogenous JH in addition to melanization hormone from suboesophageal ganglion or MRCH. Therefore, melanization appears to be critical for the later onset of ommochrome synthesis even in a larva which has been exposed to JH during the critical period.

N-terminal amino acid sequence of an insect neurohormone, melanization and reddish coloration hormone (MRCH): heterogeneity and sequence homology with human insulin-like growth factor II

Amino acid sequence Insect neurohormone Insulin‐like growth factor‐II Sequence homology Amino terminal heterogeneity Cuticular melanization

Isolation and amino terminal sequence of melanization and reddish coloration hormone (MRCH) from the silkworm, Bombyx mori

Abstract Cuticular melanization associated with the gregarious phase of the common armyworm larvae, Leucania separata , is caused by a neurohormone, melanization and reddish coloration hormone (MRCH). Two molecular species of MRCH were isolated from 211,000 heads of adult Bombyx mori with conventional column chromatography and reversed-phase high performance liquid chromatography. As little as 6 ng of purified MRCH elicited marked melanization in the cuticle of an L. separata larva. Automated Edman degradation confirmed 16 residues of N-terminal amino acid sequences of the purified MRCHs; these showed homology with each other.

Multifunctionality of PBAN-Related Neuropeptides: Melanotropic Activity of FXPRLamide Peptides

Insect neurohormones have a significant role in regulating diverse physiological events according to environmental conditions or to specific developmental stages. Recent advances in insect neuropeptide chemistry have made it possible to compare sequence homology between various neurohormones/neuropeptides and elucidate the core sequence of each neuropeptide required for biological activity.

Mode of Action of Pheromone Biosynthesis Activating Neuropeptide in Bombyx mori

The production of sex pheromone in a number of moth species is controlled by pheromone biosynthesis activating neuropeptide (PBAN), which is secreted by the subesophageal ganglion (Raina and Klun 1984; Ohguchi et al. 1985; Ando et al. 1988; Raina 1988; Rafaeli and Soroker 1989a). Recently, a growing number of investigations have focused on the identification of the target organ of PBAN for a clearer understanding of the mode of action of this hormone. In Helicoverpa (Heliothis) armigera, Bombyx mori,and Spodoptera litura, the target organ of PBAN has been demonstrated to be the pheromone gland itself (Rafaeli and Soroker 1989b; Soroker and Rafaeli 1989; Arima et al. 1991; Fonagy et al. 1992a). According to another model, in H. zea, H. virescens, and H. subflexa, Helicoverpa-Heliothis PBAN does not act on pheromone glands but on the terminal abdominal ganglion (TAG) and the abdominal nerve cord transports PBAN to the TAG, which sends a different message to the gland (Teal et al. 1989a). Moreover, direct, neural stimulation induced by PBAN is suggested via axonal branches innervating the pheromone glands in H. zea and H. virescens (Christensen et al. 1991b). In addition, reports say that the corpus bursa is the target organ of PBAN in Argyrotaenia velutinana and that it produces the “bursa factor” responsible for pheromone production (Jurenka et al. 1991a). These findings suggest diverse physiological mechanisms of PBAN action depending on the lepidopteran species.