The ‘Brain’ Hormone in the Silkworm, Bombyx mori L.

Kobayashi, Masatoshi; Kirimura, Jiro

doi:10.1038/1811217a0

Cited by 63 publications

(5 citation statements)

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“…The molting hormone, ecdysone, was isolated from the pupae of B. mori and crystallized, and its chemical structure was determined (10). The existence of the neuropeptide called prothoracicotropic hormone that stimulates the release of ecdysone was predicted (11), and the hormone was finally isolated and characterized (12).…”

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confidence: 99%

The Chitinase Gene of the Silkworm, Bombyx mori, Contains a Novel Tc-like Transposable Element

Mikitani¹,

Sugasaki²,

Shimada³

et al. 2000

Journal of Biological Chemistry

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We have determined the cDNA sequence and the genomic organization of the chitinase gene of the silkworm, Bombyx mori. The cDNA encodes 544 amino acids having 83% amino acid homology to the chitinase of the tobacoo hornworm, Manduca sexta. The total length of the gene is larger than 25 kilobase pairs, and it is separated into 11 exons. The intron-exon boundaries are all in accordance with the GT-AG rule. Also, the TATA box sequence was found in the 5 upstream region of the gene, and the gene is mapped on the seventh chromosome. A novel DNA type transposon that shows similarity to the Tc-like element was found in the third intron in some strains of B. mori; other strains, however, lack this element in the same intron. This element has long terminal inverted repeats, presumably encodes a transposase of about 340 amino acids with a DDE motif, and has an amino-terminal domain with a strong nuclear localization function. Seven other transposable elements with homologous but distinct sequences were isolated from the B. mori genome. Together with plaque hybridization results, our findings suggest that these novel elements exist in multiple copies constituting a new Tc-like transposable element family in the silkworm genome.Chitin is a ␤(1,4)-linked polymer of N-acetylglucosamine believed to be the second largest bio-mass next to cellulose. Insects utilize it as the major component of their exoskelton. When bound to proteins, chitin is strong enough both mechanically and biochemically to protect and light enough to allow smooth locomotion. However, once made as a component of the integument, chitin, unlike bone in vertebrates, has no growth capability, and the insects have to molt or undergo metamorphosis to reconstruct their integuments. Insect chitinase (family number 18 of glycosyl hydrolases, endochitinase) is induced by ecdysteroids at the time of molting and metamorphosis of the larvae to degrade most of the older chitin (1, 2). Further hydrolysis of the partially digested chitin is done by ␤1,4-Nacetylglucosaminidase (exochitinase) that is also inducible by ecdysteroid (3). The recycling of ␤1,4-N-acetylglucosamine from the older integument to the new integument was shown in larval-adult molting of Locusta migratoria (4) and larval-larval molting of Drosophila melanogaster (5). From insects, the chitinase cDNA of the tobacco hormworm Manduca sexta, has been isolated (6). With more than 4000 years of domestication history (7), Bombyx mori is one of the genetically most well studied organisms and is also a suitable model for hormone research. The existence of the molting hormone secreted from the prothoracic gland was experimentally shown using B. mori pupae (8, 9). The molting hormone, ecdysone, was isolated from the pupae of B. mori and crystallized, and its chemical structure was determined (10). The existence of the neuropeptide called prothoracicotropic hormone that stimulates the release of ecdysone was predicted (11), and the hormone was finally isolated and characterized (12).Here we describe the cDNA clonin...

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confidence: 99%

The Chitinase Gene of the Silkworm, Bombyx mori, Contains a Novel Tc-like Transposable Element

Mikitani¹,

Sugasaki²,

Shimada³

et al. 2000

Journal of Biological Chemistry

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“…More than 30 years after the discovery of the “brain factor”, two Japanese scientists focused their research on clarifying PTTH molecule in B. mori . In 1958, Kobayashi, a researcher in the National Sericultural Experiment Station, discovered that removing the brain of B. mori just after pupation in J122 × C115 arrested adult development 10. During the trial to prepare the cultivar, only J122 × C115 resulted in making the diapausing pupae incapable of resuming adult development.…”

Section: Early History Of the Study Of Silk Moth Endocrinology And Mementioning

confidence: 99%

“…In 1958, Kobayashi, a researcher in the National Sericultural Experiment Station, discovered that removing the brain of B. mori just after pupation in J122 × C115 arrested adult development. 10 During the trial to prepare the cultivar, only J122 × C115 resulted in making the diapausing pupae incapable of resuming adult development. This cultivar might have somewhat different duration for releasing the "brain factor" during pupal molting, whereas the general critical period for releasing brain factor from the brain is just before pupation.…”

Section: Early History Of the Study Of Silk Moth Endocrinology And Mementioning

confidence: 99%

Silk Moth Neuropeptide Hormones: Prothoracicotropic Hormone and Others

Nagata

Kataoka

Suzuki

2005

Annals of the New York Academy of Sciences

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The silkworm, Bombyx mori, is a very useful model species, especially in genetics, biochemistry, physiology, and molecular biology, helping researchers unravel the many mysteries involved in the insect life process. The present review describes our early contributions as chemists to the study of the molting and metamorphosis of B. mori. We also present research by Japanese scientists that contributed to the isolation and characterization of peptide hormones from B. mori.

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“…Preparation of "crude P T T H ' from 96,000 Bombyx heads -Steps I to 8 "Crude PTTH" was prepared from 96,000 Bombyx heads as reported by SUZUKI et al (1975) except that PTTH was extracted from the acetone powder of Bombyx heads with 2% aqueous sodium chloride with occasional shaking and that at each step insoluble material was separated by filtration using filter paper (Toyoroshi No. 5C) under reduced pressure.…”

Section: Experimental Conditionsmentioning

confidence: 99%

Purification and Properties of the Prothoracicotropic Hormone of the Silkworm, Bombyx Mori

Nagasawa¹,

Isogai²,

Suzuki³

et al. 1979

Dev Growth Differ

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A simple and highly reproducible procedure for partial purification of prothoracicotropic hormone (PTTH) was established starting with 96,000 male adult Bornbyx heads. Approximately 28,500-fold pulification of PTTH was accomplished with a yield of about 50% and 6 ng of the most purified preparation ("highly purified PTTH") caused adult development in a brainless Samia pupa. The peptidal nature of PTTH was reconfirmed through the effects of various enzymatic and chemical treatments on the biological activity of "highly purified PTTH". Gel-filtration indicated the molecular weight of PTTH to be 4,400.

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The ‘Brain’ Hormone in the Silkworm, Bombyx mori L.

Cited by 63 publications

References 3 publications

The Chitinase Gene of the Silkworm, Bombyx mori, Contains a Novel Tc-like Transposable Element

The Chitinase Gene of the Silkworm, Bombyx mori, Contains a Novel Tc-like Transposable Element

Silk Moth Neuropeptide Hormones: Prothoracicotropic Hormone and Others

Purification and Properties of the Prothoracicotropic Hormone of the Silkworm, Bombyx Mori

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