Remodeling of the corpora cardiaca and the corpora allata during adult metamorphosis in Bombyx mori: identification of invisible corpora cardiaca by the expression of adipokinetic hormone
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It is problematic to identify the corpora cardiaca (CC) of pupal and adult stages of Bombyx mori because of the presence of tissues similar in appearance near the associated corpora allata (CA). To find the CC, we performed in situ hybridization experiments using the adipokinetic hormone II (AKH-II) gene as a probe, as AKH-II expression occurs only in the CC. Shortly after pupation, the CC and CA began to move toward the esophagus and had attached there tightly by 4 days; during this period, the distance between the CC and CA increased from 65 to 507 μm. The CC became flattened during the remodeling period, although the CA stayed globular until adult ecdysis. In situ hybridization analyses, after the CC had been correctly identified during adult development, showed that the mRNA expression of all the mevalonate enzymes and juvenile hormone acid O-methyltransferase involved in JH synthesis occurred only in CA cells, indicating that the fluctuations of enzyme mRNA amounts in CC-CA complexes (Kinjoh et al. in Insect Biochem Mol Biol 37:808–818, 2007) were derived solely from those in the CA.
KeywordsCorpora cardiaca Corpora allata Adipokinetic hormone Juvenile hormone Bombyx mori
This work was supported by grants from the Program for the Promotion of Basic Research Activities for Innovative Biosciences (PROBRAIN) and the Japanese Society for the Promotion of Science.
- Bollenbacher WE, Granger NA (1985) Endocrinology or the prothoracicotropic hormone. In: Kerkut GA, Gilbert LI (eds) Comprehensive insect physiology, biochemistry and pharmacology, vol 7. Pergamon Press, Oxford, pp 109–151Google Scholar
- Cazal P (1948) Les glandes endocrines retro-cerebrales des insectes. Bull Biol Fr Belg (Suppl) 32:1–227Google Scholar
- Duve H, Audsley N, Weaver R, Thorpe A (2003) Allatostatins and allatotropin in the corpus cardiacum/corpus allatum complex of larval and adult lepidopterans studied by confocal laser scanning microscopy: correlation to juvenile hormone biosynthesis. Cell Tissue Res 314:281–295CrossRefPubMedGoogle Scholar
- Ichikawa T (1991) Architecture of cerebral neurosecretory cell systems in the silkworm Bombyx mori. J Exp Biol 161:217–237Google Scholar
- Kinjoh T, Kaneko Y, Itoyama K, Mita K, Hiruma K, Shinoda T (2007) Control of juvenile hormone biosynthesis in Bombyx mori: cloning of the enzymes in the mevalonate pathway and assessment of their developmental expression in the corpora allata. Insect Biochem Mol Biol 37:808–818CrossRefPubMedGoogle Scholar
- Pittendrigh CS (1965) On the mechanism of entrainment of a circadian rhythm by light cycle. In: Aschoff J (ed) Circadian clocks. North Holland, Amsterdam, pp 276–291Google Scholar
- Sedlak BJ (1985) Structure of endocrine glands. In: Kerkut GA, Gilbert LI (eds) Comprehensive insect physiology biochemistry and pharmacology, vol 7. Pergamon Press, Oxford, pp 25–60Google Scholar