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1. Activation of fat body in Periplaneta americana (Blattoptera: Blattidae) by hypertrehalosemic hormones (HTH): New insights into the mechanism of cell signalling

Creator:
Steele, John E.
Format:
print, text, and regular print
Type:
article, bibliography, model:article, and TEXT
Subject:
zoologie, entomologie, hmyz, Blattoptera, Blattidae, Periplaneta americana, hemolymfa, trehalosa, biosyntéza, kontrola biosyntézy, hypertrehalosemické hormony, mechanismus účinku, 595.2/.7, and 591.1
Language:
English
Description:
In cockroaches and certain other insects the concentration of trehalose in the hemolymph is increased by hypertrehalosemic hormone (HTH), a neuropeptide originating in the corpus cardiacum. A vital step in the action of HTH to promote conversion of glycogen stored in the fat body to trehalose is the activation of phosphorylase. The means by which HTH activates phosphorylase, with particular emphasis on its role in the regulation of intracellular calcium, is discussed. Additional information supporting the view that HTH stimulated synthesis of trehalose, and possibly its release from the trophocyte, is regulated by fatty acids and eicosanoids is presented., John E. Steele, and Lit
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2. Allatostatins and allatotropins: Is the regulation of corpora allata activity their primary function?

Creator:
Hoffmann, Klaus H., Meyering-Vos, Martina, and Lorenz, Matthias W.
Format:
print, text, and regular print
Type:
article, bibliography, model:article, and TEXT
Subject:
zoologie, fyziologie živočichů, hmyz, Crustacea, corpora allata, juvenilní hormony, ekdysteroidy, biosyntéza, kontrola biosyntézy, neuropeptidy, allatostatiny, allatotropiny, fyziologická úloha, 591.1, and 591.5
Language:
English
Description:
More than 60 neuropeptides that inhibit juvenile hormone synthesis by the corpora allata have been isolated from the brains of various insect species. Most of them are characterized by a common C-terminal pentapeptide sequence Y/FXFGL/I/V (allatostatin A family, allatostatin superfamily). Besides the allatostatin A family, allatostatic neuropeptides belonging to other two peptide families (W2W9)-allatostatins or allatostatin B family; lepidopteran allatostatin) were reported. So far, only one allatotropin has been identified. Here we discuss latest literature on the multiplicity and multifunctionality of the allatoregulating neuropeptides, their physiological significance as well as their evolutionary conservation in structure and function., Klaus H. Hoffmann, Martina Meyering-Vos, Matthias W. Lorenz, and Lit
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

3. Allatostatins in Gryllus bimaculatus (Ensifera: Gryllidae): New structures and physiological properties

Creator:
Lorenz, Mathias W., Kellner, Roland, and Hoffmann, Klaus H.
Format:
print, text, and regular print
Type:
article, bibliography, model:article, and TEXT
Subject:
zoologie, hmyz, Ensifera, Gryllidae, Gryllus bimaculatus, juvenilní hormony, biosyntéza, kontrola biosyntézy, neuropeptidy, allatostatiny, farnesol, fyziologické vlastnosti, 595.2/.7, and 591.1
Language:
English
Description:
Four peptides with allatostatic activity were isolated from brains of the Mediterranean field cricket, Gryllus bimaculatus. Three of them (Grb-AST A3: AGMYSFGL-NH2; Grb-AST A4: SRPFGFGL-NH2; Grb-AST A5: GPDHRFAFGL-NH2) belong to the wide-spread family of Y/FXFGL/I-amide peptides, the fourth (Grb-AST B5: AWDQLRPGW-NH2) is a member of the W2W9 - amide family of neuropeptides. All of these peptides are potent inhibitors of juvenile hormone (JH) biosynthesis by cricket corpora allata in vitro, causing 50% inhibition of JH biosynthesis at 0.4-3 × 10-8 M. The two peptides Grb-AST A5 and Grb-AST B5 have virtually the same potency and efficacy in inhibiting JH biosynthesis in vitro. No synergistic effect of the two peptide families with respect to the inhibition of JH biosynthesis could be observed. Peptides of both families decrease the accumulation of methylfarnesoate, the direct precursor of JH, within CA that have been incubated in farnesol-rich medium. This suggests an involvement of these ASTs in the late steps of JH biosynthesis., Mathias W., Roland Kellner, Klaus H. Hoffmann, and Lit
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

4. Juvenile hormone synthesis by corpora allata of tomato moth Lacanobia oleracea (Lepidoptera: Noctuidae), end the effects of allatostatins and allatotropin in vitro

Creator:
Audsley, Neil, Weaver, Robert J., and Edwards, John P.
Format:
print, text, and regular print
Type:
article, bibliography, model:article, and TEXT
Subject:
zoologie, fyziologie živočichů, hmyz, motýli, Noctuidae, Lacanobia oleracea, corpora allata, juvenilní hormony, biosyntéza, kontrola biosyntézy, neuropeptidy, allatostatiny, allatotropiny, účinky, pokusy in vitro, 595.2/.7, and 591.1
Language:
English
Description:
The nature and rate of juvenile hormone (JH) biosynthesis and effects of allatostatins and allatotropin have been investigated in isolated corpora allata (CA) of adults and larvae of the noctuid tomato moth, Lacanobia oleracea. In adult female CA, mean rates of synthesis were relatively constant (10-16 pmol/pr/h) at all times. However, the range of JH synthesis by individual CA of similarly aged insects was quite large (2-30 pmol/pr/h). High performance liquid chromatography (HPLC) separation shows that adult female moth CA synthesise predominantly JH I and JH II. Rates of JH synthesis in vitro are dependent on methionine concentration. Synthetic Manduca sexta allatostatin (Mas-AS) caused a dose-dependent inhibition of JH synthesis by adult female CA but only to a max. of 54%, whilst 10 µM synthetic M. sexta allatotropin caused a 37% stimulation of CA activity. At 1 mM the cockroach allatostatin, Dip-allatostatin-2, had no significant effect on JH synthesis. In larval L. oleracea, rates of JH biosynthesis were very low., Neil Audsley, Robert J. Weaver, John P. Edwards, and Lit
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public