Cardiaca-corpora Allata Research Articles

The identification and biosynthesis of two juvenile hormones from the tobacco budworm moth ( [formula omitted

Brain-corpora cardiaca-corpora allata complexes from the tobacco budworm Heliothis virescens produce both radiolabelled methyl (2E, 6E, 10Z)-10,11-epoxy-3, 11-dimethyl-7-ethyl-2, 6-tridecadienoate (JH I) and methyl (2E, 6E, 10Z)-10, 11-epoxy-3, 7, 11-trimethyl-2, 6-tridecadienoate (JH II) when cultured in medium containing L-[ methyl − 14C] methionine or sodium [1− 14C] propionate. Degradative studies of the hormones derived from propionate show the specific incorporation of the latter into the homo-isoprenoid portions of these compounds.

Juvenile hormone production by corpora allta of [formula omitted

In vitro organ cultures of corpora allata or corpora cardiaca-corpora allata complexes from Tenebrio molitor were found to produce methyl-(2E, 6E)-(10R)-10, 11- epoxy-3, 7, 11 trimethyl-2, 6-dodecadienoate (JH III). No detectable JH I or II was produced. The hormone was identified by derivation, chromatography and mass spectral analysis. A 14C radiolabel was incorporated into the methyl carbon of the ester function from precursor L-[ methyl - 14C]-methionine added to the culture medium.

Control of corpora allata function in larvae of Galleria mellonella.

1. The implantation of three brains into freshly ecdysed last instar larvae which possess at least one of the two corpora allata induces extra larval development. Implanted brains appear to produce a neurohumoral allatotropic factor.2. Corpora allata seem to be inhibited via their nervous connections 48-60 hours after the last larval-larval ecdysis and become insensitive to the allatotropic factor. Severance of the nerves innervating the corpora allata and adjacent corpora cardiaca induces extra larval development in 7% of the experimental insects and restores sensitivity to the implanted brains in as many as 20%.3. Severance of the nerves to the corpora cardiaca—corpora allata complexes or implantation of corpora cardiaca—corpora allata complexes into allatectomized larvae in some instances causes a considerable prolongation of the last larval instar. It is suggested that disconnection of the corpora allata from the brain partly removes their inhibition and induces secretion of a low titer of juvenile ho...

Water and solute uptake by rectal pads of Periplaneta americana.

Water and solute uptake by rectal pads of Periplaneta americana.

Role des neurohormones dans la différenciation sexuelle de Lampyris noctiluca

Parabiosis and grafts have been attempted with Lampyris noctiluca to discover if there is endocrine control of the formation of apical tissue of the testes by neurosecretory cells. Parabiosis between young males and females of the fourth larval stage (stage of sexual differentiation) induces maleness in the female larva. This inversion is essentially due to the androgenic hormone produced by the testes of the male larva. Parabiosis between castrated fourth larval stage males and fourth larval stage females, decerebrated and allatocardiacotectomized, shows that the larval males are able to induce maleness in female ovaries. When parabiosis is performed, the apical tissue of the testes is not yet formed. Thus the androgenic secretion is not yet elaborated, and the two grafted animals are only under the influence of the male neuroendocrine complex. Consequently the masculinization of the ovaries can only be due to the action of the male brain hormones. In grafting experiments we have substituted the brain and the corpora cardiaca-corpora allata system of a male of the fourth larval stage for the neuroendocrine complex of a fifth larval stage female. In this case we have observed the masculinization of the ovary and specially the formation of the apical tissue which is peculiar to the testicular follicles. Indeed, as we have shown in previous work, these brain cells are characterized by a very intense activity during the formation of the apical tissue. In the grafting experiments too we observe this same high activity. In summary, these results seem to provide some further arguments in favour of an endocrine rôle of the neurosecretory brain cells in the formation of apical tissue in the tests.

The effect of corpus allatum hormone on respiratory metabolism during larval development and metamorphosis of Galleria mellonella L.

Specific cycles in oxygen consumption occur in each instar of Galleria. Three types of cycles have been recognized: the first appears in the penultimate larval instar, the second in the last larval instar, and the third in the pupal instar. When the brain-corpora cardiaca-corpora allata complexes were implanted into freshly moulted last-instar larvae, metamorphosis was delayed, and two to five extra larval instars were induced. Such artificial giant larvae developed finally into giant pupae and these formed morphologically perfect giant moths. The extra larval instars retain the first type of oxygen consumption cycle, the last extra larval instars keep the second type, and the giant pupae retain the third type. Thus it follows that both the larval development controlled by the corpus allatum hormone and the metamorphosis proceeding in its absence are distinguished by specific changes in overall metabolism, regardless of the absolute age and size of the specimen. Changes in metabolic activity induced by hormones were found to be closely correlated with the degree of morphogenetic change. It is concluded that the corpus allatum hormone has an indirect effect on metabolism.

STUDIES ON THE ROLE OF THE CORPUS ALLATUM IN THE ERI-SILKWORM, PHILOSAMIA CYNTHIA RICINI

1. Pupae of Philosamia cynthia ricini in which diapause had been artificially induced by the removal of the brain, served as test animals for the effects of corpus allatum implants. Four to six corpora allata from donors in different stages induced molting in hosts which otherwise would have remained pupae. It was concluded that in Philosamia the corpus allatum, in addition to producing juvenile hormone, contains an appreciable amount of molt-inducing hormone furnished by neurosecretory cells of the brain. The interpretation is supported by the existence, in Philosamia as well as other insect species, of a neurosecretory pathway which links the secretory part of the brain with the corpora cardiaca-allata and which permits the storage of hormones produced in the brain at some distance from the cells of origin. While in most species studied so far the main storage center is the corpus cardiacum, this role may have been taken over by the corpus allatum in Philosamia.2. As might be expected, the molt induced ...