Neuropeptides that Influence Juvenile Hormone (JH) Biosynthesis in Gryllus bimaculatusa (original) (raw)
Related papers
Journal of Biological Chemistry, 1995
Four nonapeptides that inhibit juvenile hormone synthesis have been isolated by four high performance liquid chromatographic steps from extracts of the brain of the field cricket, Gryllus bimaculatus. The primary structures of these peptides were assigned by Edman degradation and mass spectrometry as Gly-Trp-Gln-Asp-Leu-Asn-Gly-Gly-Trp-NH 2 (Grb-AST B1), Gly-Trp-Arg-Asp-Leu-Asn-Gly-Gly-Trp-NH 2 (Grb-AST B2), Ala-Trp-Arg-Asp-Leu-Ser-Gly-Gly-Trp-NH 2 (Grb-AST B3), and Ala-Trp-Glu-Arg-Phe-His-Gly-Ser-Trp-NH 2 (Grb-AST B4). Each of the peptides shows high sequence similarity to the locustamyoinhibiting peptide (Lom-MIP), but is structurally different from all the allatostatins so far identified. The synthetic allatostatins Grb-AST B1-4 are potent inhibitors (50% inhibition at 10 ؊8 to 7 ؋ 10 ؊8 M) of juvenile hormone III biosynthesis by corpora allata from 3-day-old virgin females of G. bimaculatus using an in vitro bioassay. At 10 ؊7 M, Grb-AST B1 also strongly inhibits juvenile hormone III biosynthesis by corpora allata from 2-day-old adult males and 1-day-old (males and females) and 4-day-old (females) last instar larvae of G. bimaculatus. The inhibitory effect of Grb-AST B1 was also evident on corpora allata from a related species, Acheta domesticus. Inhibition of juvenile hormone synthesis by Grb-AST B1-4 is reversible.
Insect biochemistry and molecular biology, 2014
The FGLamide allatostatins (FGL/ASTs) are a family of neuropeptides with pleiotropic functions, including the inhibition of juvenile hormone (JH) biosynthesis, vitellogenesis and muscle contraction. In the cockroach, Diploptera punctata, thirteen FGLa/ASTs and one allatostatin receptor (AstR) have been identified. However, the mode of action of ASTs in regulation of JH biosynthesis remains unclear. Here, we determined the tissue distribution of Dippu-AstR. And we expressed Dippu-AstR in vertebrate cell lines, and activated the receptor with the Dippu-ASTs. Our results show that all thirteen ASTs activated Dippu-AstR in a dose dependent manner, albeit with different potencies. Functional analysis of AstR in multiple cell lines demonstrated that activation of the AstR receptor resulted in elevated levels of Ca(2+) and cAMP, which suggests that Dippu-AstR can act through the Gαq and Gαs protein pathways. The study on the target of AST action reveals that FGL/AST affects JH biosynthesis...
Peptides, 2001
In the sphinghid moth Manduca sexta, two allatoactive neuropeptides appear to be responsible for regulating juvenile hormone (JH) production by the corpora allata (CA). These peptides (M. sexta allatostatin, Mas-AS, and M. sexta allatotropin, Mas-AT) respectively inhibit and stimulate in vitro JH biosynthesis by CA in this insect. However, although Mas-AS inhibits CA in both larval and adult insects, Mas-AT is active only in adult M. sexta. The situation in other lepidopteran species is less clear-cut and, although both peptides have been detected (usually by immunologic and/or molecular techniques) in several other moths (including noctuids), their function as regulators of JH production remains uncertain. In the tomato moth Lacanobia oleracea (Lepidoptera: Noctuidae), we have previously demonstrated the occurrence of Mas-AS and/or Mas-AT in extracts of CA, brain and other organs, and have shown that both peptides are present in larval and adult forms. However, in L. oleracea, although Mas-AS inhibits larval and adult CA in vitro, it does so only at relatively high concentrations, and to a maximum of only ϳ 70%. By contrast, Mas-AT (which is also present in larval and adult L. oleracea) stimulates larval and adult CA, but is substantially more potent (ϳ100 fold) than the allatostatin. In this paper we present the results of paired, concurrent measurements (using ELISA) of levels of Mas-AS and Mas-AT in brains, CA and hemolymph (plasma and hemocytes) of L. oleracea at times when there are marked changes in JH titers. We also present data on the in vitro rates of JH biosynthesis by isolated CA, and on hemolymph JH esterase activity measured at the same critical developmental times, and discuss all of these data in relation to the putative allatoregulatory roles of the M. sexta allatotropic and allatostatic neuropeptides in L. oleracea.
European Journal of Entomology
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 widespread family of Y/FXFGL/I-amide peptides, the fourth (Grb-AST B5: AWDQLRPGW-NH2) is a member of the W2W9amide 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 x 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.
Insect Biochemistry and Molecular Biology, 2000
Eighteen peptides were isolated from brain extracts of the stick insect Carausius morosus. The peptides were purified in four steps by high-performance liquid chromatography, monitored by their ability to inhibit juvenile hormone biosynthesis by corpora allata of the cricket Gryllus bimaculatus in vitro, and chemically characterised by Edman degradation and mass spectrometry. We obtained complete primary-structure information for nine peptides, four of which belong to the peptide family characterised by a common C-terminal pentapeptide sequence-YXFGLamide. The remaining five belong to the W 2 W 9 amide peptide family, nonapeptides characterised by having the amino acid tryptophan in positions 2 and 9. The amino-acid sequence of two other peptides could not be completely resolved by means of Edman degradation; however, these peptides could be allocated to the-YXFGLamide and the W 2 W 9 amide family, respectively, by comparison of retention times, co-elution and mass spectrometry. Both classes of neuropeptides strongly inhibit juvenile hormone biosynthesis in crickets but show no inhibiting effect on the corpora allata of the stick insect.
Primary Structure of Allatostatin 4, a Nevropeptide Inhibitor of Juvenile Hormone Synthesis
Insect Science, 1995
Isolation and identification of allatostatin 4 (AST 4) from crude brain extracts of female Diploptera punctatu are described. Synthetic analogues of allatostatin 4 truncated from the N-terminal were evaluated to gain some knowledge of structure-activity correlation. AST 4 reversibly inhibits the biosynthesis of JH in vitro. AST 4 has the following sequence : Asp-Arg-Leu-Tyr-Ser-Phe-Gly-Leu-NH2. This neurohormone (AST 4) has no sequence similarity with any known neuropeptide from other organisms. Synthetic AST 4 as well as truncation fragments, including two with the five and six amino acids terminal residues deleted showed in vitro activity distinguishable from that of the native allatostatin.
Regulatory Peptides, 2004
We investigated the role of head factors and allatostatins (ASs) on the regulation of juvenile hormone (JH) synthesis in female adult mosquito. The biosynthetic activity of the Aedes aegypti corpora allata (CA) in vitro was inhibited by factors present in the head. Disconnecting the CA from the brain resulted in a significant increase in the rate of JH biosynthesis. Inhibition was not dependent on intact nervous connections; co-incubation of CA with brains or brain extracts resulted in a significant decrease of JH biosynthesis. This inhibitory effect of brain extracts was reversible and heat stable; extracts lost the inhibitory activity after proteinase K digestion suggesting a peptidic structure. In a first attempt to elucidate the nature of this inhibitory factor, we tested in our CA in vitro system the effect of members of two families of allatostatins already described in mosquitoes. Anopheles gambiae PISCF-allatostatin (homolog to Manduca PISCF-allatostatin) significantly inhibited JH synthesis, while Ae. aegypti YXFGL-amide-allatostatins (homologs to cockroach YXFGL-amide-allatostatins) did not affect JH synthesis. These results represent the first description of an allatostatic effect of PISCF-allatostatins outside the Lepidoptera. D
Allatostatins: Diversity in Structure and Function of an Insect Neuropeptide Family
Annals of The New York Academy of Sciences, 1997
The juvenile hormones (JHs) are a unique group of sesquiterpenoids, identified definitively only in insects, that are responsible for the maintenance of juvenile characteristics. A reduction in JH titer is generally believed to be required for metamorphosis to the adult form. Reproductive functions in most adult female insect species are also regulated by JH, and oocyte growth and maturation, including vitellogenesis, show an absolute dependency on JH-in the absence of the hormone, oocyte growth is arrested.' JH titer is regulated in part by the rate of biosynthesis within the endocrine glands known as the corpora allata (CA), which can he considered analogous to the adenohypophysis of vertebrates. Based on the now classic experiments involving severance of nerve tracts originating in the brain and innervating the CA, Scharrer demonstrated that CA function was under close-range neural control. Scharrer suggested that signals in the hemolymph might also act to regulate the CA.2 Consistent with Scharrer's original observations, the regulation of JH biosynthesis by CA is now known to be stimulated or inhibited by two groups of peptides, allatotropins and allatostatins (ASTs), respectively. This review will examine the ASTs which occur in multiple forms, are pleiotropic in function, and are widely distributed in both neural and nonneural tissue. The structural and functional features of the ASTs appear to parallel the vertebrate somatostatins and may provide one of the best examples of the parallel evolution of peptides.* MOLECULAR ISOLATION AND CHARACTERIZATION OF THE COCKROACH ALLATOSTATIN PRECURSOR The initial characterization of the first complete AST coding region was accomplished by polymerase chain reaction (PCR) amplifications3 of specific sequence from cDNA derived from mKNA isolated from the brains of virgin females of the cockroach Diploptera p~n c t a t a .~ Initially, a pair of highly degenerate primers was used to produce an internal DNA consensus sequence representing the peptide sequence of Dip-AST2
Journal of Biological Chemistry, 2006
Aedes aegypti PISCF-allatostatin or allatostatin-C (Ae-AS-C) was isolated using a combination of high performance liquid chromatography and enzyme-linked immunosorbent assay (ELISA). The matrix-assisted laser desorption/ionization timeof-flight (TOF) mass spectrum of positive ELISA fractions revealed a molecular mass of 1919.0 Da, in agreement with the sequence qIRYRQCYFNPISCF, with bridged cysteines. This sequence was confirmed by matrix-assisted laser desorption/ ionization tandem TOF/TOF mass spectrometry analysis. The corresponding Ae-AS-C cDNA was amplified by PCR, and the sequence of the peptide was confirmed. An in vitro radiochemical assay was used to study the inhibitory effect of synthetic Ae-AS-C on juvenile hormone biosynthesis by the isolated corpora allata (CA) of adult female A. aegypti. The inhibitory action of synthetic Ae-AS-C was dose-dependent; with a maximum at 10 ؊9 M. Ae-AS-C showed no inhibitory activity in the presence of farnesoic acid, an immediate precursor of juvenile hormone, indicating that the Ae-AS-C target is located before the formation of farnesoic acid in the pathway. The sensitivity of the CA to inhibition by Ae-AS-C in the in vitro assay varied during the adult life; the CA was most sensitive during periods of low synthetic activity. In addition, the levels of Ae-AS-C in the brain were studied using ELISA and reached a maximum at 3 days after eclosion. These studies suggest that Ae-AS-C is an important regulator of CA activity in A. aegypti. Juvenile hormone (JH) 3 titers must be modulated to permit the normal progress of development and reproduction in insects (1, 2). In adult female Aedes aegypti mosquitoes, JH levels are low at adult eclosion, elevated in sugar-fed females, and low again after a blood meal (3). JH titer is fundamentally controlled by the rate of biosynthesis in the corpora allata gland (CA) (4). The rate of CA activity is, in turn, regulated, in part, by allato-regulatory peptides that exert either allatostatic (inhibitory) or allatotropic (stimulatory) activity (5, 6). We previously reported that the biosynthetic activity of the A. aegypti CA in vitro was inhibited by mosquito brain extracts (5), and then we used confocal, laser-scanning microscopy studies to show specific patterns of immunostaining for AS-C in the cells of the brain of A. aegypti (7). Here we describe the purification, biochemical, molecular, and functional characterization of A. aegypti PISCF-allatostatin (or Ae-AS-C). It is the first comprehensive report since the original description of a member of this peptide family as an inhibitor of JH synthesis in the lepidopteran Manduca sexta (8). In addition, we describe the developmental stage-dependent Ae-AS-C inhibition of JH synthesis, as well as the changes in peptide levels in head samples. These studies suggest that Ae-AS-C is an important regulator of CA activity in A. aegypti.
2013
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.