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
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
Two anti-peptide antisera (anti-A and anti-B) raised against Gryllus bimaculatus allatostatin A1 (Grb-AST A1) and B1 (Grb-AST B1), respectively, were applied in the peroxidase-antiperoxidase (PAP) immunohistochemical technique on complete series of sections from the brain, suboesophageal ganglion, corpora cardiaca (CC), and corpora allata (CA) of G. bimaculatus. Both antisera yielded intense staining of numerous cells and nerve fibres. Serial sections, alternately stained with anti-A and anti-B confirmed that the anti-B generally stained more cells and nerves. Extensive immunoreactivity in the retrocerebral complex suggests that the CC and CA may represent a storage and/or release site for both allatostatin types or allatostatin-like molecules produced in the brain., Günther Witek, Peter Verhaert, Matthias W. Lorenz, Klaus H. Hoffmann, and Lit
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