scholarly journals Action of the Prothoracic Gland on the Insect Integument in Vitro

1972 ◽  
Vol 7 (2) ◽  
pp. 71-78 ◽  
Author(s):  
Noriaki AGUI ◽  
Yasuo KIMURA ◽  
Masatsugu FUKAYA
Keyword(s):  
Prothoracic Gland ◽  
Insect Integument

In vitro action of prothoracicotropic hormone on RNA-synthesis in the prothoracic gland of the silkworm, Bombyx mori

1986 ◽  
Vol 32 (8) ◽  
pp. 711-717 ◽  
Author(s):  
Yasuo Aizono ◽  
Noboru Matsuo ◽  
Yoshihiro Yoshida ◽  
Gunki Funatsu ◽  
Masaru Funatsu ◽  
...  
Keyword(s):  
Bombyx Mori ◽  
Rna Synthesis ◽  
Prothoracic Gland ◽  
Prothoracicotropic Hormone ◽  
Silkworm Bombyx Mori

scholarly journals Ecdysteroidogenesis in Heliothis virescens (Lepidoptera: Noctuidae): Recombinant Prothoracicotropic Hormone and Brain Extract Show Comparable Effects

2019 ◽  
Vol 19 (3) ◽  
Author(s):  
Marisa Nardiello ◽  
Rosanna Salvia ◽  
Andrea Scala ◽  
Carmen Scieuzo ◽  
Sabino Aurelio Bufo ◽  
...  
Keyword(s):  
Heliothis Virescens ◽  
Complex Mixture ◽  
Prothoracic Gland ◽  
Tobacco Budworm ◽  
Brain Extract ◽  
In Vitro Tests ◽  
Prothoracicotropic Hormone ◽  
Lepidoptera Noctuidae

Abstract Prothoracicotropic hormone (PTTH) is a neuropeptide that triggers a cascade of events within the prothoracic gland (PG) cells, leading to the activation of all the crucial enzymes involved in ecdysone biosynthesis, the main insect steroid hormone. Studies concerning ecdysteroidogenesis predicted PTTH action using brain extract (BE), consisting in a complex mixture in which some components positively or negatively interfere with PTTH-stimulated ecdysteroidogenesis. Consequently, the integration of these opposing factors in steroidogenic tissues leads to a complex secretory pattern. A recombinant form of prothoracicotropic hormone (rPTTH) from the tobacco budworm Heliothis virescens (F.) (Lepidoptera: Noctuidae) was expressed and purified to perform in vitro tests in a standard and repeatable manner. A characterization of rPTTH primary and secondary structures was performed. The ability of rPTTH and H. virescens BE to stimulate ecdysteroidogenesis was investigated on the third day of fifth larval stage. rPTTH activity was compared with the BE mixture by enzyme immunoassay and western blot, revealing that they equally stimulate the production of significant amount of ecdysone, through a transduction cascade that includes the TOR pathway, by the phosphorylation of 4E binding protein (4E-BP) and S6 kinase (S6K), the main targets of TOR protein. The results of these experiments suggest the importance of obtaining a functional pure hormone to perform further studies, not depending on the crude brain extract, composed by different elements and susceptible to different uncontrollable variables.

The Halloween genes code for cytochrome P450 enzymes mediating synthesis of the insect moulting hormone

2006 ◽  
Vol 34 (6) ◽  
pp. 1256-1260 ◽  
Author(s):  
K.F. Rewitz ◽  
R. Rybczynski ◽  
J.T. Warren ◽  
L.I. Gilbert
Keyword(s):  
Cytochrome P450 ◽  
Fat Body ◽  
Larval Instar ◽  
Primary Source ◽  
Pupal Stage ◽  
Prothoracic Gland ◽  
Cytochrome P450 Enzymes ◽  
Biosynthetic Activity ◽  
Prothoracic Glands

The developmental events occurring during moulting and metamorphosis of insects are controlled by precisely timed changes in levels of ecdysteroids, the moulting hormones. The final four sequential hydroxylations of steroid precursors into the active ecdysteroid of insects, 20E (20-hydroxyecdysone), are mediated by four cytochrome P450 (P450) enzymes, encoded by genes in the Halloween family. Orthologues of the Drosophila Halloween genes phantom (phm; CYP306A1), disembodied (dib; CYP302A1), shadow (sad; CYP315A1) and shade (shd; CYP314A1) were obtained from the endocrinological model insect, the tobacco hornworm Manduca sexta. Expression of these genes was studied and compared with changes in the ecdysteroid titre that controls transition from the larval to pupal stage. phm, dib and sad, which encode P450s that mediate the final hydroxylations in the biosynthesis of ecdysone, were selectively expressed in the prothoracic gland, the primary source of ecdysone during larval and pupal development. Changes in their expression correlate with the haemolymph ecdysteroid titre during the fifth (final) larval instar. Shd, the 20-hydroxylase, which converts ecdysone into the more active 20E, is expressed in tissues peripheral to the prothoracic glands during the fifth instar. Transcript levels of shd in the fat body and midgut closely parallel the enzyme activity measured in vitro. The results indicate that these Halloween genes are transcriptionally regulated to support the high biosynthetic activity that produces the cyclic ecdysteroid pulses triggering moulting.

In Vitro Culture of Embryos in the Silkworm, Bombyx Mori L

1963 ◽  
Vol 40 (4) ◽  
pp. 735-739
Author(s):  
TAKEO TAKAMI
Keyword(s):  
In Vitro Culture ◽  
Bombyx Mori ◽  
Embryo Culture ◽  
Prothoracic Gland ◽  
Prothoracic Glands ◽  
Hormonal Action ◽  
Bombyx Mori L ◽  
The Brain ◽  
Silkworm Bombyx Mori

1. Silkworm embryos decapitated before the differentiation of neuroblasts, or before differentiation of the prothoracic glands, were cultured in vitro. 2. Brainless embryos which developed from these decapitated explants detached the cuticle, suggesting that the ‘moult’ of cultured embryos does not require any hormonal action of the brain in the silkworm at least for its initiation. 3. The prothoracic gland was not found to be necessary even for occurrence of the embryonic moult. 4. The author's results obtained by embryo culture in the silkworm are contrary to those obtained by ligaturing experiments in the locusts. This difference between the two cases present important questions about the nature of the moult in cultured silkworm embryos, which must be answered by further investigations.

scholarly journals ISOLATION OF EPIDERMAL CELL PAIRS FROM AN INSECT, TENEBRIO MOLITOR, FOR DUAL WHOLE-CELL RECORDING OF LARGE-CONDUCTANCE GAP-JUNCTIONAL CHANNELS

1993 ◽  
Vol 178 (1) ◽  
pp. 261-267
Author(s):  
D. Churchill ◽  
S. Caveney
Keyword(s):  
Cell Model ◽  
Cell Voltage ◽  
Epidermal Cells ◽  
Moult Cycle ◽  
Whole Cell ◽  
Cell Recording ◽  
Insect Integument ◽  
Gap Junctional

The segmented insect integument, composed of an epidermal monolayer and its cuticular secretion, is a paradigm for the study of pattern formation during development (Lawrence, 1992). Epidermal activity during development may be coordinated by the transfer of cytoplasmic molecules through cell-cell gap-junctional channels (reviewed in Caveney, 1985). Gap junctions within intact epidermal segments exhibit dynamic changes in their permeability properties during the moult cycle in vivo (Caveney, 1978) and with exposure to the developmental hormone 20-hydroxyecdysone in vitro (Caveney and Blennerhassett, 1980). In addition, the row of epidermal cells at segment borders has distinct permeability properties creating developmental and communication compartments (Warner and Lawrence, 1982; Blennerhassett and Caveney, 1984). This paper documents a method for isolating epidermal cells that are suitable for dual whole-cell voltage-clamp studies of gap-junctional currents. We have identified a large-conductance gap-junctional channel in cell pairs with octanol- reduced junctional currents. This cell model may be useful for examining mechanisms of gap- junctional channel gating during development.

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