Developmental change of bombyxin content in the brain of the silkmoth Bombyx mori (original) (raw)
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Journal of Insect Physiology, 1999
Changes in the hemolymph bombyxin titer of the adult silkmoth Bombyx mori were investigated by time-resolved fluoroimmunoassay. Immediately after eclosion, hemolymph bombyxin titers were low in both males and females, and then increased steeply in males to a very high level and this high titer was maintained for at least 3 h, whereas the titer increment in females was small and transient. The difference in the change of bombyxin titer between males and females suggests that bombyxin is responsible for the regulation of physiological changes underlying sexually different activities of the adult moths. However, no evidence was obtained that bombyxin controls adult metabolism as far as the effects of bombyxin on the concentrations of carbohydrates and lipids in the hemolymph were investigated. The change in the hemolymph trehalose concentration was almost the same between sexes, and between intact and neck-ligated moths. Furthermore, bombyxin injection did not affect the hemolymph trehalose concentration nor trehalase activity in the muscle. Although the hemolymph lipid concentration rose after eclosion in males, it was not influenced by bombyxin. These results exhibit striking contrast to the results of our previous study, in which bombyxin showed hypotrehalosemic activity in the larval stage, thus indicating that the action of bombyxin changes during metamorphosis.
Journal of Insect Physiology, 1987
The presence and fluctuation of prothoracicotropic hormone (PTTH) activity have been shown in brainless Bombyx mori pupae and in developing embryos. The embryonic PITH is only effective in eliciting adult development of brainless pupae. PTTH activity first became detectable in embryos which had developed almost to the stage of differentiation of their neuroendocrine systems. The hormone was partially purified from pharate first-instar larvae (1 day before hatching) and approx a 300-fold purification was achieved. 0.2 pg of the partial purified hormone can evoke adult development in brainless pupae. The molecular weight of the hormone was estimated to be 20,000-30,000 daltons by gel-filtration on a Sephadex G-SO. Two distinct forms of PTTH are present in developing embryos of B. mori.
Development, Growth and Differentiation, 1992
Monoclonal antibodies were raised against pure, native bombyxin-ll (bombyxin-ll antibody) and against a synthetic nonapeptide corresponding to the amino-terminus of the C-peptide of the bombyxin precursor protein (C-peptide antibody). The bombyxin-ll antibody recognized both bombyxin and probombyxin. A radioimmunoassay for bombyxin using the bombyxin-ll antibody was developed, and developmental change in the titer of bombyxin immunoreactivity in the Bombyx hemolymph was investigated. The titer was low and almost constant during the fourth and early fifth instars. In the male, the titer rose abruptly 3 days after the beginning of wandering. One day after pupation it rose again steeply to reach the maximal level which lasted until the middle of the developing adult stage. The titer decreased thereafter and increased again at adult emergence. In the female, the pattern of titer fluctuation was similar to that in the male, but the female titers during pupal-adult development were 2-3 times higher than the male titers.
Proceedings of the National Academy of Sciences, 1989
Four genes encoding bombyxin have been located in a 14-kilobase Bombyx genomic DNA segment. All of these genes encode preprobombyxin, the precursor molecule for bombyxin, with the domain organization of signal peptide/B chain/C peptide/A chain. Bombyxins are classified as family A or B according to their sequence homology. Two genes, each belonging to a different family, are closely apposed to form a pair with opposite orientation, presumably forming a regulatory unit for transcription. Genomic Southern blot hybridization suggested that there are many such gene pairs in the Bombyx genome. Differences between bombyxin genes and vertebrate insulin-family genes indicate that different mechanisms operate in the evolution of invertebrate and vertebrate insulin-family genes.
Amino acid sequence of a prothoracicotropic hormone of the silkworm Bombyx mori
Proceedings of the National Academy of Sciences, 1986
We have determined the complete amino acid sequence of 4K-PTTH-H, one of three forms of the Mr 4400 prothoracicotropic hormone of the silkworm Bombyx mori, active to brainless pupae of Samia cynthia ricini. Like vertebrate insulin, it consists of two nonidentical peptide chains (A and B chains). The A chain consists of 20 amino acid residues. The B chain is a mixture of four microheterogeneous peptides, two of which consist of 28 residues, and the other two, of 26 residues. 4K-PTTH-II has considerable sequence homology (40%) with human insulin, and it resembles porcine relaxin both in the carboxyl-terminal cysteine residue of the A chain and in the amino-terminal pyroglutamic acid residue of the B chain. The identical distribution ofthe six cysteine residues also indicates that 4K-PTTH-ll belongs to the insulin family.