The Experts below are selected from a list of 90 Experts worldwide ranked by ideXlab platform
Roland Kellner - One of the best experts on this subject based on the ideXlab platform.
-
structure elucidation and biological activity of an unusual adipokinetic hormone from Corpora cardiaca of the butterfly vanessa cardui
FEBS Journal, 2000Co-Authors: Gabriele V. Köllisch, Matthias W. Lorenz, Roland Kellner, Peter Verhaert, Klaus H HoffmannAbstract:A structurally unusual member of the adipokinetic hormone/red pigment-concentrating hormone peptide family was isolated from Corpora cardiaca of the painted lady butterfly, Vanessa cardui. Its primary structure was assigned by Edman degradation and nano-electrospray-time-of-flight mass spectrometry as pQLTFTSSWGGK (Vac-AKH). Vac-AKH represents the first 11mer and the first nonamidated peptide in this family. The peptide shows significant adipokinetic activity in adult specimens of V. cardui. Injection of 10 pmol of synthetic Vac-AKH into 4-day-old decapitated males resulted in an ≈ 150% increase of hemolymph lipids after 90 min. Half maximal adipokinetic activity was achieved with about 0.1 pmol of Vac-AKH. During a 2-h incubation of Corpora cardiaca/Corpora allata complexes in medium containing 50 mm KCl, significant amounts of Vac-AKH were released from the glands.
-
A novel peptide in the AKH/RPCH family isolated from the Corpora cardiaca of the Emperor dragonfly, Anax imperator.
Peptides, 1994Co-Authors: Gerd Gade, Markus Peter-erik Janssens, Roland KellnerAbstract:Using a heterologous (in locusts and cockroaches) and a homologous bioassay, we have isolated the neuropeptide pGlu-Val-Asn-Phe-Ser-Pro-Ser-Trp-NH2 from extracts of Corpora cardiaca of the Emperor dragonfly, Anax imperator. The sequence elucidation was achieved by Edman degradation of the deblocked peptide and by electrospray mass spectrometry. Low concentrations of the synthetic peptide injected into the Emperor dragonfly increased the hemolymph lipid concentration, suggesting a possible role of the peptide in lipid homeostasis during flight. Therefore, it is named Ani-AKH, Anax imperator adipokinetic hormone.
-
a novel peptide in the akh rpch family isolated from the Corpora cardiaca of the emperor dragonfly anax imperator
Peptides, 1994Co-Authors: Gerd Gade, Markus Peter-erik Janssens, Roland KellnerAbstract:Using a heterologous (in locusts and cockroaches) and a homologous bioassay, we have isolated the neuropeptide pGlu-Val-Asn-Phe-Ser-Pro-Ser-Trp-NH2 from extracts of Corpora cardiaca of the Emperor dragonfly, Anax imperator. The sequence elucidation was achieved by Edman degradation of the deblocked peptide and by electrospray mass spectrometry. Low concentrations of the synthetic peptide injected into the Emperor dragonfly increased the hemolymph lipid concentration, suggesting a possible role of the peptide in lipid homeostasis during flight. Therefore, it is named Ani-AKH, Anax imperator adipokinetic hormone.
-
primary structures of neuropeptides isolated from the Corpora cardiaca of various cetonid beetle species determined by pulsed liquid phase sequencing and tandem fast atom bombardment mass spectrometry
Biological chemistry Hoppe-Seyler, 1992Co-Authors: Gerd Gade, Roland Kellner, Andreas L Lopata, Kenneth L RinehartAbstract:A peptide with the same retention time on gradient reversed-phase high-performance liquid chromatography was present in the Corpora cardiaca of 5 scarabaeid beetles, subfamily Cetoniinae: the three fruit beetle species Pachnoda marginata, P. sinuata and P. aemulae and the two protea beetle species Trichostetha fascularis and T. albopicta. Crude Corpora cardiaca material from P. sinuata had a small hypertrehalosaemic effect in American cockroaches and a very weak hyperlipaemic activity in migratory locusts. Injections into P. sinuata caused hypertrehalosaemia when a dose of 1.0 Corpora cardiaca equivalents was injected. An identical neuropeptide was isolated, by RP-HPLC, and sequenced by pulsed-liquid phase sequencing employing Edman chemistry after enzymically deblocking the N-terminal 5-oxopyrrolidine-2-carboxylic acid residue, as well as by collision-induced decomposition tandem fast atom bombardment mass spectrometry. The peptide is a blocked octapeptide: Glu-Leu-Asn-Tyr-Ser-Pro-Asp-TrpNH2, previously designated Mem-CC. The synthetic peptide is able to elicit haemolymph carbohydrates in P. sinuata upon injection of low doses. Activity studies using synthetic analogues of this peptide revealed that Tyr4 may be important for receptor recognition/binding. The peptide is synthesized in intrinsic cells of the corpus cardiacum as shown by in vitro inCorporation of [3H]Trp and [14C]Tyr in Mem-CC.
Gerd Gade - One of the best experts on this subject based on the ideXlab platform.
-
Effects of metabolic neuropeptides from insect Corpora cardiaca on proline metabolism of the African fruit beetle, Pachnoda sinuata.
Journal of insect physiology, 1999Co-Authors: Lutz Auerswald, Gerd GadeAbstract:The effect of neuropeptides from the Corpora cardiaca of the fruit beetle Pachnoda sinuata on proline metabolism has been investigated in vivo. Conspecific injections of a crude extract from Corpora cardiaca cause an increase of the concentration of proline in the haemolymph by nearly 20% and a decrease of the concentration of alanine, the precursor in proline synthesis, by about 64% when compared with a water-injected group. Purification of an extract of Corpora cardiaca on reversed-phase liquid chromatography revealed two distinct UV absorbance and fluorescence peaks that cause hyperprolinaemia in the fruit beetle. The major peak is the previously identified octapeptide Mem-CC; the second peak is also a peptide, but its primary sequence remains, as yet, unidentified. Synthetic Mem-CC elicited time- and dose-dependent increases/decreases of the concentrations of proline and alanine in the haemolymph respectively. Furthermore, the receptor for this peptide seems to be specific in P. sinuata: only peptides of the large family of adipokinetic hormones with an Asp, Asn or Gly residue at position 7 could elicit biological activity, whereas those with a Trp, Ser or Val residue at this position did not have any activity.
-
A novel peptide in the AKH/RPCH family isolated from the Corpora cardiaca of the Emperor dragonfly, Anax imperator.
Peptides, 1994Co-Authors: Gerd Gade, Markus Peter-erik Janssens, Roland KellnerAbstract:Using a heterologous (in locusts and cockroaches) and a homologous bioassay, we have isolated the neuropeptide pGlu-Val-Asn-Phe-Ser-Pro-Ser-Trp-NH2 from extracts of Corpora cardiaca of the Emperor dragonfly, Anax imperator. The sequence elucidation was achieved by Edman degradation of the deblocked peptide and by electrospray mass spectrometry. Low concentrations of the synthetic peptide injected into the Emperor dragonfly increased the hemolymph lipid concentration, suggesting a possible role of the peptide in lipid homeostasis during flight. Therefore, it is named Ani-AKH, Anax imperator adipokinetic hormone.
-
a novel peptide in the akh rpch family isolated from the Corpora cardiaca of the emperor dragonfly anax imperator
Peptides, 1994Co-Authors: Gerd Gade, Markus Peter-erik Janssens, Roland KellnerAbstract:Using a heterologous (in locusts and cockroaches) and a homologous bioassay, we have isolated the neuropeptide pGlu-Val-Asn-Phe-Ser-Pro-Ser-Trp-NH2 from extracts of Corpora cardiaca of the Emperor dragonfly, Anax imperator. The sequence elucidation was achieved by Edman degradation of the deblocked peptide and by electrospray mass spectrometry. Low concentrations of the synthetic peptide injected into the Emperor dragonfly increased the hemolymph lipid concentration, suggesting a possible role of the peptide in lipid homeostasis during flight. Therefore, it is named Ani-AKH, Anax imperator adipokinetic hormone.
-
primary structures of neuropeptides isolated from the Corpora cardiaca of various cetonid beetle species determined by pulsed liquid phase sequencing and tandem fast atom bombardment mass spectrometry
Biological chemistry Hoppe-Seyler, 1992Co-Authors: Gerd Gade, Roland Kellner, Andreas L Lopata, Kenneth L RinehartAbstract:A peptide with the same retention time on gradient reversed-phase high-performance liquid chromatography was present in the Corpora cardiaca of 5 scarabaeid beetles, subfamily Cetoniinae: the three fruit beetle species Pachnoda marginata, P. sinuata and P. aemulae and the two protea beetle species Trichostetha fascularis and T. albopicta. Crude Corpora cardiaca material from P. sinuata had a small hypertrehalosaemic effect in American cockroaches and a very weak hyperlipaemic activity in migratory locusts. Injections into P. sinuata caused hypertrehalosaemia when a dose of 1.0 Corpora cardiaca equivalents was injected. An identical neuropeptide was isolated, by RP-HPLC, and sequenced by pulsed-liquid phase sequencing employing Edman chemistry after enzymically deblocking the N-terminal 5-oxopyrrolidine-2-carboxylic acid residue, as well as by collision-induced decomposition tandem fast atom bombardment mass spectrometry. The peptide is a blocked octapeptide: Glu-Leu-Asn-Tyr-Ser-Pro-Asp-TrpNH2, previously designated Mem-CC. The synthetic peptide is able to elicit haemolymph carbohydrates in P. sinuata upon injection of low doses. Activity studies using synthetic analogues of this peptide revealed that Tyr4 may be important for receptor recognition/binding. The peptide is synthesized in intrinsic cells of the corpus cardiacum as shown by in vitro inCorporation of [3H]Trp and [14C]Tyr in Mem-CC.
J.e. Steele - One of the best experts on this subject based on the ideXlab platform.
-
Enhancement of hypertrehalosemic hormone biosynthesis by trehalose in isolated cockroach (Periplaneta americana) Corpora cardiaca in vitro
Journal of Insect Physiology, 1992Co-Authors: M.a. Khan, J.e. SteeleAbstract:Abstract Using [ 3 H]tryptophan as a precursor, the rate of production and release of cardioacceleratory hormone-I and -II by isolated Corpora cardiaca of Periplaneta americana was quantified in vitro . Striking differences in the rate of radiolabelled tryptophan inCorporation into these peptides occurred depending on the carbohydrate composition of the incubation media. With medium containing only sucrose, a low rate of hormone accumulation was found. This rate increased more than five-fold when 50 mM trehalose was included in the medium. The effect of trehalose was rather specific and could not be mimicked by 5 mM glucose, although extremely high levels of glucose did stimulate some glands. The enhanced rate of cardioacceleratory hormone-I and -II accumulation appears to be due to an increased rate of peptide synthesis rather than a lowered rate of release.
G. Gäde - One of the best experts on this subject based on the ideXlab platform.
-
A comparative immunocytochemical study using an antiserum against a synthetic analogue of the Corpora cardiaca peptide Pea-CAH-I (MI, neurohormone D) of Periplaneta americana.
Cell and tissue research, 1996Co-Authors: Manfred Eckert, J. Gabriel, H. Birkenbeil, G. Greiner, Jürgen Rapus, G. GädeAbstract:An antiserum against the octapeptide Pea-CAH-I, a member of the adipokinetic hormone/red pigment-concentrating hormone family, has been produced for immunocytochemical staining in insects and various other invertebrate species. The anti-Pea-CAH-I serum stains the glandular Corpora cardiaca cells of those insect species that synthesize identical or structurally similar peptides. In the Corpora cardiaca of species producing peptides with a different C-terminus, these cells remain unstained. Pea-CAH-I-like immunoreactivity has also been found in neurons of the central nervous system of all invertebrate orders studied. The antiserum recognizes the C-terminal sequence Pro-Asn-Trp-NH2 of the Pea-CAH-I molecule as established by enzyme immunoassay. The widespread Pea-CAH-I-like immunoreactivity in all nervous systems of the studied animals probably does not reflect the presence of Pea-CAH-I but the occurrence of peptides carrying similar epitopes.
Liliane Schoofs - One of the best experts on this subject based on the ideXlab platform.
-
Melatonin-induced neuropeptide release from isolated locust Corpora cardiaca
Peptides, 2005Co-Authors: Jurgen Huybrechts, A. De Loof, Liliane SchoofsAbstract:A method, based on a combination of mass spectrometry and liquid chromatography, was developed to investigate the release of neuropeptides from isolated locust Corpora cardiaca. Melatonin, octopamine, trehalose and forskolin were administered to the perifused glands. The neuropeptides present in the releasates (spontaneous versus induced) were visualized by either conventional or capillary HPLC. Identification was achieved by means of MALDI-TOF MS and/or nanoflow-LC-Q-TOF MS. The observed effects of these chemicals regarding AKH release were in line with previous studies and validate the method. The most important finding of this study was that administration of melatonin stimulated the release of adipokinetic hormone precursor related peptides (APRP 1 and APRP 2), neuroparsins (NP A1, NP A2 and NP B) and diuretic peptide.
-
Identification of a glycogenolysis-inhibiting peptide from the Corpora cardiaca of locusts
Endocrinology, 2003Co-Authors: Elke Clynen, Arnold De Loof, Jurgen Huybrechts, Geert Baggerman, Jan M. Van Doorn, Dick J. Van Der Horst, Liliane SchoofsAbstract:A mass spectrometric study of the peptidome of the neurohemal part of the Corpora cardiaca of Locusta migratoria and Schistocerca gregaria shows that it contains several unknown peptides. We were able to identify the sequence of one of these peptides as pQSDLFLLSPK. This sequence is identical to the part of the Locusta insulin-related peptide (IRP) precursor that is situated between the signal peptide and the B-chain. We designated this peptide as IRP copeptide. This IRP copeptide is also present in the pars intercerebralis, which is likely to be the site of synthesis. It is identical in both L. migratoria and S. gregaria. It shows no effect on the hemolymph lipid concentration in vivo or muscle contraction in vitro. The IRP copeptide is able to cause a decreased phosphorylase activity in locust fat body in vitro, opposite to the effect of the adipokinetic hormones and therefore possibly represents a glycogenolysis-inhibiting peptide.
-
Osmotic lysis of Corpora cardiaca using distilled water reveals the presence of partially processed peptides and peptide fragments
Physiological Entomology, 2003Co-Authors: Jurgen Huybrechts, Arnold De Loof, Elke Clynen, Liliane SchoofsAbstract:Abstract. A simple, single-step aqueous extraction method has been developed to study the neuropeptide content of small neuroendocrine organs. Perifusion of these tissues with deionized water causes osmotic bursting of the cells and release of their content into the surrounding fluid. The neuropeptides are immediately retained from the perifusion fluid using disposable C18 cartridges. After one separation step and mass spectrometry, it was possible to identify a large number of known neuropeptides from the Corpora cardiaca of Locusta migratoria (L). Also present in the extract were a number of neuropeptide fragments and two incompletely processed peptides. Using this method, a 959Da peptide present in the Corpora cardiaca was sequenced de novo. The full sequence, deduced using Collision Induced Dissociation Tandem Mass Spectrometry (CID MS/MS), is Ser-Pro-Leu-Asp-Ala-His-His-Leu-Ala. This nonapeptide is predicted from the gene encoding the ion transport peptide precursor and from the gene encoding the ion transport-like peptide precursor. In both cases, this nonapeptide, which was named ion transport peptide-copeptide, is flanked by the signal sequence at the N-terminus and a dibasic cleavage site (Lys-Arg) at the C-terminus. This structural feature is common to many physiologically important locust preproneuropeptides and indicates that this copeptide might have a physiological function, but this is not yet known.
-
Several isoforms of locustatachykinins may be involved in cyclic AMP-mediated release of adipokinetic hormones from the locust Corpora cardiaca.
General and comparative endocrinology, 1999Co-Authors: Dick R Nassel, Paul Passier, Liliane Schoofs, J. H. B. Diederen, H. G. B. Vullings, C. Tomas Lundquist, Dick J. Van Der HorstAbstract:Abstract Four locustatachykinins (LomTK I–IV) were identified in about equal amounts in extracts of Corpora cardiaca of locusts, using reverse-phase high-performance liquid chromatography and radioimmunoassay with synthetic LomTK I–IV as standards. Brain extracts also contained the four isoforms in roughly equimolar concentrations. Retrograde tracing of the nervi corporis cardiaci II (NCC II) in vitro with Lucifer yellow in combination with LomTK immunocytochemistry revealed that about half of the secretomotor neurons in the lateral part of the protocerebrum projecting into the glandular lobe of the Corpora cardiaca (CCG) contain LomTK-immunoreactive material. Since the four LomTKs are present in the CCG, these four or five neurons in each hemisphere are likely to contain colocalized LomTK I–IV. The role of two of the LomTKs in the regulation of the release of adipokinetic hormones (AKHs) from the adipokinetic cells in the CCG in the locust was investigated. Experiments performed in vitro showed that LomTK I and II induced release of AKH in a dose-dependent manner. These peptides also rapidly and transiently elevated the cyclic AMP-content of the CCG. The peak level of cyclic AMP occurred about 45 seconds after stimulation with LomTK. These results support the proposal that LomTKs are involved in controlling the release of the adipokinetic hormones and suggest that all LomTK isoforms may participate in this cyclic AMP-mediated event.
