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Larry L. Keeley Sheila M. Sowa Aaron S. Hesson 《Archives of insect biochemistry and physiology》1995,28(4):313-324
An in vitro bioassay suitable for routine use to investigate hypertrehalosemic hormone (HTH)-dependent trehalose biosynthesis was developed for the cockroach fat body. Blaberus discoidalis fat bodies were isolated and divided so that eight matched pieces from a single tissue could be compared for multiple control and experimental treatments. Optimum incubation conditions and the properties of HTH-dependent trehalose synthesis were determined. Dose-response studies determined an EC50 of 0.044 nM HTH for male fat body and 0.16 nM HTH for female tissue. HTH increased trehalose production by male fat body 3-fold compared to only a 67% maximum increase by the female tissue, and only the male tissue was used in subsequent studies. Fat body required only 5-min exposure to HTH for maximum trehalose production for 1 h. Trehalose synthesis was inhibited by ≥ 15 mM trehalose in the incubation medium. The fat body showed a developmental increase in trehalose synthesis in vitro that was reflected by hemolymph trehalose in vivo. Basal and HTH-related trehalose synthesis were low between days 0 and 10, increased 3-fold by day 20, and were high thereafter. These studies have established baseline data for future investigations to identify the signal transduction mechanisms involved in HTH regulation of fat body metabolism. © 1995 Wiley-Liss, Inc. 相似文献
3.
Dick J. Van der Horst Simon F. Vroemen Wil J.A. Van Marrewijk 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1997,117(4):463-474
The mobilization of carbohydrate and lipid reserves from the insect fat body as fuels for migratory flight activity is controlled by adipokinetic hormone (AKH), of which in Locusta migratoria three different forms occur: AKH-I, -II and -III. In fat body in vitro, each AKH is capable of activating glycogen phosphorylase and of stimulating cAMP production, but only in the presence of extracellular Ca2+. The hormones stimulate both the influx and the efflux of Ca2+, the higher influx probably causing an increase in intracellular [Ca2+]. AKH enhances the production of inositol phosphates among which inositol 1,4,5-triphosphate may mediate the mobilization of Ca2+ from intracellular stores. Evidence is presented in favor of the occurrence of a capacitative calcium entry mechanism. Results suggest that transduction of the AKH signal occurs through stimulatory G protein-coupled receptor(s). A tentative model is presented for the interactions between the AKH signaling pathways in the locust fat body cell. AKH-induced lipid mobilization during flight requires the presence in the insect blood of high-density lipophorin (HDLp) particles and apolipophorin III (apoLp-III). Both protein components are synthesized in the fat body. In the locust, the two integral, nonexchangeable HDLp apolipophorins (apoLp-I and -II) were shown to originate from a common precursor; an mRNA of 10.3 kb seems to code for this precursor protein. The models proposed for lipophorin assembly and secretion in a number of insects are not in agreement. The exchangeable apoLp-III may occur in two or more isoforms; locust apoLp-III is secreted from the fat body as one of the two isoforms and in the hemolymph converted into the truncated second one. The rationale for this process is as yet unknown. 相似文献
4.
《Insect Biochemistry》1987,17(5):765-769
The N-terminal glutamic acid analog of the decapeptide locust adipokinetic hormone-I, [Glu1]AKH-I, was prepared by solid-phase synthesis and derivatized to [4-hydroxyphenyl propionyl-Glu1]AKH-I. This derivative was radioiodinated on the 4-hydroxyphenyl function ([125I]AKH analog). [Glu1]AKH-I was coupled to bovine serum albumin to produce rabbit antiserum. This, together with the [125I]AKH analog was utilized to develop a highly selective radioimmunoassay procedure (RIA) for detecting AKH-I in locusts. Methanol extracts of locust brain contain two factors (BI and BII) that inhibit protein synthesis in excised fat body tissue of vitellogenic female locusts. BI also elicits lipid mobilization when injected into adult male locusts. The HPLC retention time of BI on an RP-18 column is identical to that of locust adipokinetic hormone (AKH-I), both synthetic and derived from adult corpora cardiaca (CC). The second brain factor (BII) does not exhibit lipid mobilizing activity. One tissue-equivalent of BI contains 33 ng of AKH-I as determined by RIA, compared to 450 ng native HPLC-separated AKH-I in locust CC. 相似文献
5.
R Ziegler K Eckart R D Jasensky J H Law 《Archives of insect biochemistry and physiology》1991,18(4):229-237
Structure-activity studies were performed for adipokinetic hormone (AKH) in Manduca sexta. Seven naturally occurring and four synthetic peptides of the red pigment concentrating hormone (RPCH)/AKH family were tested in larvae of M. sexta for activation of glycogen phosphorylase in fat body. pGlu at the N-terminal was found to be important for activity of peptides; however, Manduca AcGly1AKH is partially active. The amino acids at all positions appear to be of importance for activity, with the possible exception of the two serine residues in positions six and seven. Generally, the more amino acids are exchanged, the less the peptide will bind to the receptor. In M. sexta a beta-bend appears not to be important for the binding of peptides. Peptides ten amino acids long appear to be more active than shorter ones. 相似文献
6.
Martínez-Pérez F Becerra A Valdés J Zinker S Aréchiga H 《Journal of molecular evolution》2002,54(6):703-714
Precursor structures of various members of the neuropeptide family adipokinetic hormone/red pigment concentrating hormone
(AKH/RPCH) of mandibular arthropods and the APGWamide family of mollusks were compared. Amino acid alignments showed a common
overall architecture (signal peptide, active peptide, related peptide), with a similar α helix–random coil secondary structure.
DNA sequence alignments revealed close similarities between the genes encoding for the peptides of the two families. The APGWamide
genes are larger than the AKH/RPCH genes. The sequence environment occupied by introns is similar in AKH/RPCH and APGWamide
genes. Such similarities suggest that these peptide families might have been originated by gene rearrangements from a common
ancestor having either an AKH/RPCH/APGWamide-like structure or both an AKH/RPCH-like and an APGWamide-like structures. In
the former model, DNA fragments could have been gained when the ancestor evolved to mollusks and it could have lost nucleotides
when the progression to mandibular arthropods took place. In the second model, AKH/RPCH-like structures could have been fused
during evolution toward mandibular arthropods, whereas in mollusks they could have been lost with the possible amplification
of the APGWamide-like structure. Loss of domains in exon 1 may have originated the signal peptide and the first codon of the
active RPCH. In exon 2, loss of domains possibly determined the junctions of codons 2 to 5 with the loss of a APGWamide copy;
exon 3 underwent fewer variations. The similarity of the mollusk APGWamide precursors is closer to that of the RPCH family
than the insect AKH family, indicating an earlier evolutionary departure. 相似文献
7.
Aminolevulinic acid (ALA) synthase activity was measured in fat body mitochondria from adult male Blaberus discoidalis cockroaches. The enzyme reached its maximum activity at 4 to 6 days of adult age and then dropped to a minimal level which was maintained throughout the remainder of the study period. ALA synthase activity was doubled by allylisopropylacetamide and showed a half-life of about 6 h at 25 °C. Enzyme activity was depressed by long-term allatectomy. However, juvenile hormone administration in vivo did not significantly stimulate the enzyme relative to appropriate controls, and endocrine regulation of fat body ALA synthase remains inconclusive. Hemin inhibited ALA synthase activity, suggesting that fat body heme synthesis could be regulated by end-product inhibition. 相似文献
8.
《Insect Biochemistry》1990,20(3):319-323
Vitellogenesis in locusts is synchronized with the cyclic maturation of oocytes. Vitellogenesis by excised fat body of gravid females is differentially inhibited 80–90% when locust adipokinetic hormone I (AKH-I) is added to the incubation media. Hemolymph methanolic extracts completely inhibit fat body protein synthesis in vitro when the donor females are at the end of the ovarian cycle (6 mm stage), but not when taken from earlier stages. Hemolymph methanolic extracts from vitellogenic females at the 6 mm stage are separated by HPLC into three distinct inhibitors of protein synthesis, one of which is AKH-I. AKH-RIA of hemolymph during the first ovarian cycle reveals no AKH-I during active vitellogenesis, but a marked increase to about 5 ng per female at the end of egg maturation. A development of responsiveness to AKH-I is evident in female fat body as vitellogenesis proceeds. AKH-I is involved in the negative control of vitellogenesis. 相似文献
9.
M H Schaffer B E Noyes 《BioEssays : news and reviews in molecular, cellular and developmental biology》1987,7(2):67-71
Genetic manipulation and purification techniques are facilitating research into the biology of arthropod neuropeptides. The red pigment concentrating hormone (RPCH)/ adipokinetic hormone (AKH) family are a conserved group of peptides which were first recognized for their hormonal activities. Biosynthesis of AKH in the grasshopper seems to proceed via a large protein precursor (12 kDa) in the cell body of the neuron, which implies precise coordination of synthesis and neural activity. Beginning with a 10 amino acid stretch of known precursor protein sequence, an oligonucleotide primer approach is being used to clone a recombinant AKH gene. Once achieved, this will allow fundamental questions on the biochemistry and physiology of neuropeptides to be addressed. Such work in an arthropod system raises the intriguing possibility of studying neuropeptide level and synthetic activity in single, defined neurons. 相似文献
10.
《Insect Biochemistry》1987,17(8):1133-1137
Methanol extracts of vitellogenic female locust brains contain two factors that inhibit protein synthesis in fat body tissue excised from such individuals. One of these factors (BI) elicits lipid mobilization when injected into adult male locusts. The retention times of BI on an RP-18 column and on an RP-4 column are identical to those of synthetic locust adipokinetic hormone (AKH-I) on each of these columns. Half maximal inhibition of protein synthesis in excised adult locust fat bodies is exerted by 0.05 brain extract equivalents of BI, which is equivalent to activity elicited by 1.5 pmol of AKH-I, as previously determined by AKH-radioimmunoassay. Enzymatic hydrolysis of the N-terminal pyroglutamate, followed by amino acid sequence analysis, indicates that the structure of BI is similar to that of the decapeptide AKH-I synthesized in the glandular lobe of the locust corpora cardiaca (CC). Incorporation of [5-3H]tryptophan into BI of locust brains incubated in vitro indicates that the AKH-I present in the brain is synthesized in situ and is not transported from the CC. Similar incorporation of radiolabel into AKH-I is obtained when excised CC are incubated in vitro. 相似文献
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Candy DJ 《Insect biochemistry and molecular biology》2002,32(11):1361-1367
A new procedure for the measurement of adipokinetic hormone (AKH) concentrations in locust (Schistocerca gregaria) haemolymph is described: Haemolymph is extracted with chloroform/methanol/water and the aqueous layer is fractionated with reverse-phase cartridges and HPLC. The fractions corresponding to AKH-I (Lom-AKH-I) and AKH-II (Scg-AKH-II) are then measured in a competitive binding assay using specific antibodies and [3H]AKHs. The procedures could be applied to any peptides containing N-terminal pyroglutamate residues including all members of the adipokinetic/hyperglycaemic/red pigment concentrating hormone family. Results show that the concentrations of both AKH-I and AKH-II increase within 5 min of initiation of flight and are maintained at approx. 15-fold (AKH-I) and 6-fold (AKH-II) the resting levels over flights of at least 60 min. Poisoning of locusts with either the insecticide deltamethrin or with potassium chloride also caused release of hormones. Starvation for 6 h caused elevation of hormone levels in 5th instar nymphs, but starvation for 6 or 20 h had little effect on hormones in adults, despite an increase in haemolymph diacylglycerols at 20 h. 相似文献
13.
Injections of immunogens, such as beta-1,3-glucan or lipopolysaccharide (LPS), bring about a marked hyperlipaemia with associated changes in lipophorins and apolipophorin-III in the haemolymph of Locusta migratoria. These changes are similar to those observed after injection of adipokinetic hormone (AKH). The possibility that endogenous AKH is released as part of the response to these immunogens is investigated using passive immunisation against AKH-I, and measurement of AKH-I titre in the haemolymph after injection of immunogens. The data presented show that, despite the similarity of the changes brought about by the presence of immunogens in the haemolymph to those brought about by AKH, there is no release of endogenous AKH after injection of laminarin or LPS. A direct effect of the immunogens on release of neutral lipids by the fat body cannot be demonstrated in vitro, and the mechanism by which hyperlipaemia is induced during immune challenge remains uncertain. 相似文献
14.
Jane L. Witten Martin H. Schaffer Michael OShea J.Carter Cook Mark E. Hemling Kenneth L. Rinehart 《Biochemical and biophysical research communications》1984,124(2):350-358
Amino acid sequences have been assigned to two cockroach neuropeptides (Glu-Val-Asn-Phe-Ser-Pro-Asn-Trp-NH2, M I, and Glu-Leu-Thr-Phe-Thr-Pro-Asn-Trp-NH2, M II) by application of fast atom bombardment mass spectrometry, including high resolution and linked scan (metastable) studies. The peptides show considerable homology with two other invertebrate neuropeptides, adipokinetic hormone (AKH, from a locust) and red pigment concentrating hormone (RPCH, from a prawn), whose fast atom bombardment spectra were also studied. M I and M II are thus members of a family of structurally-related invertebrate neuropeptides. 相似文献
15.
Gabriele Gaus Lewis H. Kleinholz Günter Kegel Rainer Keller 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,160(4):373-379
Summary Red-pigment-concentrating hormone (RPCH) has been isolated from nerve tissue of six decapod crustaccan species. The primary structure of three of the six hormones, i.e., those ofCancer magister, Carcinus maenas andOrconectes limosus, was determined by manual microsequencing as: pELNFSPGW-NH2. This sequence is identical to that of RPCH fromPandalus borealis, the only previously known sequence of a crustacean RPCH. The other three hormones fromLiocarcinus puber, Nephrops norvegicus, andPacifastacus leniusculus could not be characterized completely. However, amino acid compositions, the presence of N-terminal pGlu, and the blocked N-terminal ends are in accordance with the primary structure established for the other three RPCHs. We suggest that all six peptides have the same amino acid sequence. These results indicate that RPCH, which is likely to be related to the peptides of the AKH family in insects, is highly conserved among crustacean species. This is in remarkable contrast to the high degree of molecular evolution exemplified by the many different AKH-like peptides among insect species.Abbreviations
AKH
adipokinetic hormone
-
Aufs
absorption units full scale
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BSA
bovine serum albumin
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ECH
erythrophore concentrating hormone (=RPCH)
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EDTA
ethylenediamine-tetra-acetic acid
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HOAc
acetic acid
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HPLC
high pressure liquid chromatography
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O.D.
optical density
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PDH
pigment dispersing hormone
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PGAP
pyroglutamate aminopeptidase
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RPCH
red-pigment-concentrating hormone (=ECH)
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SOG
suboesophageal ganglion
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TFA
trifluoroacetic acid 相似文献
16.
J. E. Steele K. Garcha D. Sun 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2001,130(4):226
The rate of synthesis of inositol trisphosphate (InsP3) in trophocytes derived from disaggregated cockroach (Periplaneta americana) fat body increases following treatment of the cells with hypertrehalosemic hormone I or II (HTH-I, -II) in vitro. Trophocytes preloaded with [3H]inositol display a significant increase in InsP3 synthesis as early as 15 s after addition of the hormone. When the trophocytes are pre-incubated with LiCl and subsequently incubated with HTH the [3H] content of the InsP3 fraction is greater than that found with HTH alone. This is taken as evidence that inositol monophosphate phosphatase is part of the mechanism for clearing InsP3 from the cytosol. In contrast to HTH, octopamine, which is also capable of exerting a hypertrehalosemic effect in the cockroach, does not increase the synthesis of InsP3. 1-Octadecyl-2-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3), a potent and selective inhibitor of phosphatidylinositol phospholipase C, blocks the activation of phosphorylase by HTH-I as well as the hypertrehalosemic effect induced by the hormone. 相似文献
17.
《Insect Biochemistry》1984,14(2):151-157
In fifth instar larvae of Locusta migratoria the haemolymph lipid concentration is elevated after injection of adipokinetic hormone (AKH). This hyperlipaemic response in larvae remains substantially lower than in adults; over 75% of the mobilized lipid consists of diacylglycerol. In addition, unlike adult locusts, fifth instar larvae also exhibit a consistent, though moderate, hypertrehalosaemic response to AKH. The increases of both lipid and carbohydrate concentrations in larvae are dose-dependent, showing a significant linear regression on log dose in the range 0.2–20 pmol AKH.Glycogen phosphorylase in the fat body of fifth instar larvae as well as young adults is activated on injection of AKH, the percentage active phosphorylase increasing linearly with log dose in the range 0.04–20 pmol AKH. For a given response, a somewhat higher dose of AKH is needed in larvae than in young adults.Fat body glycogen phosphorylase is strongly activated during the period of the larval-adult ecdysis, when active phosphorylase accounts for almost half of the total enzyme, which is approximately ten times more than it is two days before, and two days after the ecdysis.The corpora cardiaca of fifth larval instar locusts already possess the potencies to elevate carbohydrate and lipid concentrations in larval haemolymph, and to activate fat body glycogen phosphorylase. 相似文献
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Zubrzycki IZ 《Zeitschrift für Naturforschung. C, Journal of biosciences》2000,55(1-2):125-128
Lom-AKH-I is a member of the adipokinetic hormone/red pigment concentrating hormone (AKH/RPCH) family of peptides found in flying insects. A molecular dynamics simulation at room temperature (293 K) in water has been performed to survey the folding path of the Lom-AKH-I peptide in water and to establish the secondary structure of Lom-AKH-I. The obtained results indicate the presence of an undefined extended conformation. 相似文献
20.
DALIBOR KODRÍK HEATHER G. MARCO PETR ŠIMEK RADOMÍR SOCHA PAVEL ŠTYS GERD GÄDE 《Physiological Entomology》2010,35(2):117-127
The adipokinetic hormones (AKHs) from 15 species of heteropteran Hemiptera (encompassing eight families, six superfamilies and three infraorders) have been isolated and structurally identified using liquid chromatography coupled with mass spectrometry. None of the structures are novel and all are octapeptides. These peptide sequence data are used, together with the previously available AKH sequence data on Heteroptera, to create a larger dataset for comparative analyses. This results, in total, in AKH sequences from 30 species (spanning 13 families), which are used in a matrix confronted with the current hypotheses on the phylogeny of Heteroptera. The expanded dataset shows that all heteropterans have octapeptide AKHs; three species have two AKHs, whereas the overwhelming majority have only one AKH. From a total of 11 different AKH peptides known from Heteroptera to date, three AKHs occur frequently: Panbo‐red pigment‐concentrating hormone (RPCH) (×10), Schgr‐AKH‐II (×6) and Anaim‐AKH (×4). The heteropteran database also suggests that particular AKH variants are family‐specific. The AKHs of Heteroptera: Pentatomomorpha (all terrestrial) are not present in Nepomorpha (aquatic) and Gerromorpha: Gerridae (semiaquatic); AKHs with a Val in position 2 are absent in the Pentatomomorpha (only AKHs with Leu2 are present), whereas Val2 predominates in the nonterrestrial species. An unexpected diversity of AKH sequences is found in Nepomorpha, Nepoidea, Nepidae and Nepinae, whereas Panbo‐RPCH (which has been identified in all infraorders of decapod crustaceans) is present in all analysed species of Pentatomidae and also in the only species of Tessaratomidae investigated. The molecular evolution of Heteroptera with respect to other insect groups and to crustaceans is discussed 相似文献