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L Schoofs

Publications and source records attributed to L Schoofs.

At least 73 records · Page 4Linked to original sources
PubMed1996

Isolation of NEB-LFamide, a novel myotropic neuropeptide from the grey fleshfly.

A methanolic extract of 350,000 adult grey fleshflies Neobellieria bullata, was prepared and screened for myotropic activity. After fractionation on the first column, all fractions were screened in two heterologous (Locusta oviduct and Leucophaea hindgut) and one homologous (Neobellieria hindgut) myotropic bioassay. We here report the purification of one fraction, which stimulates the contractions of the Locusta oviduct. Electrospray Mass Spectrometry of the peptide revealed a molecular mass of 1395.82. The primary structure has been determined as AYRKPPFNGSLF-amide. This novel peptide was designated Neb-LF-amide. This sequence is different from the other known myotropic peptides in insects. The threshold concentration of the synthetic peptide is 1 x 10(-7) M on the Locusta oviduct. On the hindgut of Neobellieria or Leucophaea, the synthetic peptide is not active. By use of a polyclonal antiserum raised against the synthetic peptide, immunoreactivity was localized in median neurosecretory cells in the pars intercerebralis of the fly brain, indicating that Neb-LF-amide is a neuropeptide.

Amino Acid Sequence↗
PubMed1996

Isolation and identification of a cAMP generating peptide from the flesh fly, Neobellieria bullata (Diptera: Sarcophagidae).

The Manduca sexta Malpighian tubule assay system, developed to monitor adenylate cyclase activity, was used in combination with HPLC to isolate a novel cAMP generating peptide from 350,000 whole flesh flies, Neobellieria bullata. Mass spectrometry revealed a molecular mass of 5,047 daltons, and Edman degradation the following sequence: AGAEAEKLSGLSKYFNGTTMAGRANVAKATYAVIGLIIAYNVMKPKKK. This 48-mer peptide, called Neb-cGP, does not belong to the corticotropin releasing factor family of insect diuretic peptides. Electrophoresis and subsequent immunoblotting of peptides immunoprecipitated from a homogenate of entire flies showed that one fly contained approximately 0.003 to 0.03 micrograms Neb-cGP and that 10 micrograms represents the lowest immunostainable amount on a Western blot.

Amino Acid Sequence↗
PubMed1996

Isolation and characterization of Locusta migratoria accessory gland myotropin I (Lom-Ag-MT-I) from the brain of the Colorado potato beetle, Leptinotarsa decemlineata.

A novel myotropic Colorado potato beetle peptide, active in the Locusta oviduct motility assay, was isolated from a methanolic extract of 9,000 brain complexes of adult Leptinotarsa decemlineata by means of HPLC. Its sequence is Gly-Phe-Lys-Asn-Val-Ala-Leu-Ser-Thr-Ala-Arg-Gly-Phe-NH2. This peptide is identical to Lom-AG-MT-I, a myotropin previously isolated from the male accessory glands of Locusta migratoria, using the L. migratoria oviduct motility bioassay as a monitoring system. It strongly stimulated the frequency, amplitude, and tonus of the myogenic oviduct contractions, even at low concentrations.

Amino Acid Sequence↗
PubMed1995

Isolation and identification of Lom-SG-SASP, a salivation stimulating peptide from the salivary glands of Locusta migratoria.

From a methanolic extract of about 2500 salivary glands of Locusta migratoria a peptide was isolated which stimulates cAMP production in the salivary glands and salivation. Maldi-TOFMS revealed a mass of 1779 Da. The primary structure of the peptide is NH2-EVGDLFKEWLQGNMN-COOH. The peptide is named Locusta migratoria-Salivary Gland-Salivation Stimulating Peptide (Lom-SG-SASP) because of its simulating effect on salivation. Lom-SG-SASP displays no relevant sequence similarities with any other known peptide from vertebrate or invertebrate sources. The effect of synthetic Lom-SG-SASP on cAMP production in the salivary glands and on salivation is discussed.

Amino Acid Sequence↗
PubMed1995

Isolation of Ala1-proctolin, the first natural analogue of proctolin, from the brain of the Colorado potato beetle.

Methanolic head and brain extracts of the Colorado potato beetle contain several myotropins, active in the Locusta oviduct motility assay. Reversed phase high performance liquid chromatography (RP HPLC) gave evidence for the presence of three myotropic factors, with retention times close to that of proctolin. Both strongly stimulated the frequency, amplitude and tonus of the myogenic oviduct contractions. Gas phase sequencing and FAB-MS revealed that, besides proctolin (Arg-Tyr-Leu-Pro-Thr), two natural proctolin analogues were present. The first one is Ala-Tyr-Leu-Pro-Thr and is designed as Ala1-proctolin. The threshold concentration for biological activity of Ala1-proctolin was 10(-7) M, compared to 10(-10) M for proctolin itself. Ala1-proctolin is the first identified biological analogue of proctolin. The full nature of the first amino acid of a third proctolin-analogue (x-Tyr-Leu-Pro-Thr) is probably a modified amino acid of which the identity could as yet not be revealed. Our results suggest the existence of a family of proctolin-like peptides.

Amino Acid Sequence↗
PubMed1995

Identification, characterization, and immunological localization of a novel myotropic neuropeptide in the Colorado potato beetle, Leptinotarsa decemlineata.

A novel myotropic heptapeptide was isolated from an extract of 54,000 heads of adult Leptinotarsa decemlineata by means of high performance liquid chromatography (HPLC), using the Locusta migratoria oviduct motility bioassay as monitoring system. The full primary structure was established as H-Ala-Tyr-Asn-Gly-Pro-Leu-Ala-NH2. This peptide, designated as Led-MNP-I, has a unique structure and does not belong to any known vertebrate or invertebrate peptide family. Two adjacent Led-MNP-I-immunoreactive perikarya were found in each optic lobe and in each half of all thoracic ganglia. Its absence from the pars intercerebralis and neurohemal organs suggests that Led-MNP-I is not a neurohormone but a neurotransmitter or neuromodulator. Treatment of isolated oviducts with varying concentrations of Led-MNP-I did not elicit significant changes in the level of cAMP concentration, suggesting that cAMP does not act as a second messenger for Led-MNP-I. Instead, Led-MNP-I induces an elevation of IP3. Treatment with Led-MNP-I did not stimulate cAMP production in the Colorado beetle brain, but this could be due to the very small number of receptive cells present. Both tissues contained a forskolin-sensitive adenylate cyclase enzyme.

Amino Acid Sequence↗
PubMed1995

Locustamyoinhibin-like (Lom-MIH) immunoreactivity in the head ganglia of the insects Neobellieria bullata, Mamestra brassicae, Leptinotarsa decemlineata and Leucophaea maderae.

A polyclonal antibody raised against locustamyoinhibin (Lom-MIH), a myoinhibiting neuropeptide of the locust Locusta migratoria, was used to search for locustamyoinhibin-like immunoreactivity in the central nervous system of the gray fleshfly, Neobellieria bullata, the Colorado potato beetle, Leptinotarsa decemlineata, the cabbage moth, Mamestra brassicae and the cockroach, Leucophaea maderae. In L. maderea, immunoreactive cells are present in the pars intercerebralis (PI), in nerve fibers leading to the corpus cardiacum (CC) and in the CC themselves. In N. bullata, three groups of cells are positive: one in the PI, one in the pars lateralis and one in the suboesophageal ganglion. In M. brassicae, there are only positive cells in the PI. No immunoreactivity was found in L. decemlineata. These results indicate that the presence of Lom-MIH immuno-like molecules is not restricted to the orthopterans, and that they can be localized in different parts of the head ganglia.

Amino Acid Sequence↗
PubMed1995

Folliculostatins, gonadotropins and a model for control of growth in the grey fleshfly, Neobellieria (sarcophaga) bullata.

The sequences of two folliculostatic peptides of the fleshfly Neobellieria bullata have been determined recently. The first peptide (Neb-TMOF: H-NPTNLH-OH), originates from a 75 kDa precursor protein found in vitellogenic oocytes. The hexapeptide directly inhibits the synthesis of trypsin-like enzymes in the gut, and thus lowers the concentration of yolk polypeptides in the hemolymph. It also inhibits the biosynthesis of ecdysone in the larval ring gland. Therefore, it could also be named prothoracicostatic hormone (Neb-PTSH). The second peptide (Neb-colloostatin: H-SIV-PLGLPVPIGPIVVGPR-OH) acts on previtellogenic follicles and is a cleaved product of a collagen-like precursor molecule. Our results indicate that peptides that are cleaved from matrix proteins could act as growth-inhibiting factors. Gonadotropin releasing hormone (GnRH)-immunolike peptides were not identified, but progress is being made in the isolation and characterization of factors which stimulate cAMP production by the ovary. Using these results, a novel model of growth control in which matrix proteins play an important role as a potential source of growth regulators has been developed.

Amino Acid Sequence↗
PubMed1995

Immunological evidence for an allatostatin-like neuropeptide in the central nervous system of Schistocerca gregaria, Locusta migratoria and Neobellieria bullata.

Methanolic brain extracts of Locusta migratoria inhibit in vitro juvenile hormone biosynthesis in both the locust L. migratoria and the cockroach Diploptera punctata. A polyclonal antibody against allatostatin-5 (AST-5) (dipstatin-2) of this cockroach was used to immunolocalize allatostatin-5-like peptides in the central nervous system of the locusts Schistocerca gregaria and L. migratoria and of the fleshfly Neobellieria bullata. In both locust species, immunoreactivity was found in many cells and axons of the brain-retrocerebral complex, the thoracic and the abdominal ganglia. Strongly immunoreactive cells were stained in the pars lateralis of the brain with axons (NCC II and NCA I) extending to and arborizing in the corpus cardiacum and the corpora allata. Although many neurosecretory cells of the pars intercerebralis project into the corpus cardiacum, only 12 of them were immunoreactive and the nervi corporis cardiaci I (NCC I) and fibers in the nervi corporis allati II (NCA II) connecting the corpora allata to the suboesophageal ganglion remained unstained. S. gregaria and L. migratoria seem to have an allatostatin-like neuropeptide present in axons of the NCC II and the NCA I leading to the corpus cardiacum and the corpora allata. All these data suggest that in locusts allatostatin-like neuropeptides might be involved in controlling the production of juvenile hormone by the corpora allata and, perhaps, some aspects of the functioning of the corpus cardiacum as well. However, when tested in a L. migratoria in-vitro juvenile hormone-biosynthesis assay, allatostatin-5 did not yield an inhibitory or stimulatory effect. There is abundant AST-5 immunoreactivity in cell bodies of the fleshfly N. bullata, but none in the CA-CC complexes. Apparently, factors that are immunologically related to AST-5 do occur in locusts and fleshflies but, the active portion of the peptide required to inhibit JH biosynthesis in locusts is probably different from that of AST-5.

Amino Acid Sequence↗
PubMed1994

Partial identification, synthesis and immunolocalization of locustamyoinhibin, the third myoinhibiting neuropeptide isolated from Locusta migratoria.

A blocked neuropeptide that suppresses the motility of the cockroach hindgut has been isolated from an extract of 9000 brain-corpora cardiaca-corpora allata-suboesophageal ganglion complexes of Locusta migratoria. Biological activity was monitored during HPLC purification by observing the myoinhibiting activity of column fractions on the isolated hindgut of Leucophaea maderae. Due to the low amount of material left after deblocking, this myoinhibiting peptide--designated as locustamyoinhibin or Lom-MIH--could only be partially sequenced: pGlu-X-Tyr-X'-Lys-Gln-Ser-Ala-Phe-Asn-Ala-Val-Ser-NH2. Nevertheless, the carboxy-terminal nonamer sequence (Lom-MIH5-13) was synthesized and also displayed myoinhibiting activity, indicating that the biologically active core lies in the carboxy-terminal sequence. Lom-MIH shows no sequence similarities with other peptides from vertebrate or invertebrate sources and is the third myoinhibiting peptide identified in Locusta migratoria. A polyclonal antiserum was raised against Lom-MIH5-13 and used to investigate the distribution of immunoreactive peptide in the central nervous system and its associated neurohaemal structures. Two groups of neurons with somata in the optic lobes show locustamyoinhibin (Lom-MIH)-like immunoreactivity. These groups have somata at the dorsal and ventral edge of the lamina ganglionaris. The neurons have dense ramifications in the lamina, with processes extending into the first optic chiasma and into the accessory medulla. Four cell bodies were detected in the protocerebrum, and two cells were found at the externo-lateral edge of the tritocerebrum. No immunoreactive perikarya could be observed in the suboesophageal ganglion nor in the ganglia of the ventral nerve cord. Neither the corpora cardiaca nor the neurohaemal organs of the ventral nerve cord showed immunolabelling. Therefore, our findings provide anatomical evidence for a central neurotransmitter role of Lom-MIH.

Amino Acid Sequence↗
PubMed1993

Isolation, identification, and synthesis of AKH-I4-10 from Locusta migratoria.

A heptapeptide was isolated from brain-corpora cardiaca-corpora allata-suboesophageal ganglion extracts of the locust, Locusta migratoria. Biological activity was monitored during HPLC purification by observing the myotropic effect of column fractions on the isolated hindgut of Leucophaea maderae. The primary structure of this myotropic peptide was established as: Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2. The chromatographic and biological properties of the synthetic peptide were the same as those of the native peptide, thus confirming structural analysis. This heptapeptide is identical to the carboxyterminal heptamer of AKH-I and therefore designated as AKH-I4-10. AKH-I4-10 has no adipokinetic activity. AKH-I4-10 is most likely a breakdown product of Lom-AKH-I, suggesting that an endopeptidase which cleaves between Asn and Phe is present in the brain complex of L. migratoria. Such an endopeptidase has recently been characterized in in synaptic membranes of the nervous system of Schistocerca gregaria.

Amino Acid Sequence↗
PubMed1993

Isolation, identification and synthesis of locustapyrokinin II from Locusta migratoria, another member of the FXPRL-amide peptide family.

1. A blocked decapeptide was isolated from brain corpora cardiaca-corpora allata suboesophageal ganglion extracts of the locust, Locusta migratoria. Biological activity was monitored during HPLC purification by observing the myotropic effect of column fractions on the isolated hindgut of Leucophaea maderae. 2. The primary structure of this myotropic peptide was established as: pGlu-Ser-Val-Pro-Thr-Phe-Thr-Pro-Arg-Leu-NH2. 3. The chromatographic and biological properties of the synthetic peptide were the same as those of the native peptide, thus confirming structural analysis. 4. This decapeptide is the sixth natural analog of a series of locust peptides with a Phe-X-Pro-Arg-Leu-NH2 carboxyterminus. This carboxyl terminal sequence is also found in other peptides identified in other insects and it is the biological active core sequence for diverse biological activities: muscle contraction, pheromone production, pigment synthesis and diapauze. 5. Like the locustamyotropins and locustapyrokinin I, locustapyrokinin II stimulates contractions of the oviduct in Locusta.

Amino Acid Sequence↗
PubMed1993

The myotropic peptides of Locusta migratoria: structures, distribution, functions and receptors.

The search for myotropic peptide molecules in the brain, corpora cardiaca, corpora allata suboesophageal ganglion complex of Locusta migratoria using a heterologous bioassay (the isolated hindgut of the cockroach, Leucophaea maderae) has been very rewarding. It has lead to the discovery of 21 novel biologically active neuropeptides. Six of the identified Locusta peptides show sequence homologies to vertebrate neuropeptides, such as gastrin/cholecystokinin and tachykinins. Some peptides, especially the ones belonging to the FXPRL amide family display pleiotropic effects. Many more myotropic peptides remain to be isolated and sequenced. Locusta migratoria has G-protein coupled receptors, which show homology to known mammalian receptors for amine and peptide neurotransmitters and/or hormones. Myotropic peptides are a diverse and widely distributed group of regulatory molecules in the animal kingdom. They are found in neuroendocrine systems of all animal groups investigated and can be recognized as important neurotransmitters and neuromodulators in the animal nervous system. Insects seem to make use of a large variety of peptides as neurotransmitters/neuromodulators in the central nervous system, in addition to the aminergic neurotransmitters. Furthermore quite a few of the myotropic peptides seem to have a function in peripheral neuromuscular synapses. The era in which insects were considered to be "lower animals" with a simple neuroendocrine system is definitely over. Neural tissues of insects contain a large number of biologically active peptides and these peptides may provide the specificity and complexity of intercellular communications in the nervous system.

Amino Acid Sequence↗
PubMed1992

Distribution of locustamyotropin-like immunoreactivity in the nervous system of Locusta migratoria.

Locustamyotropin-like immunoreactivity was visualized in the nervous system of Locusta migratoria by means of the peroxidase antiperoxidase method. Highly specific antibodies to the carboxy-terminus of the locustamyotropins were obtained by elution through an affinity column to which Lom-MT II was covalently bound. Specific cells in the nervous system of Locusta migratoria contain substances immunoreactive to anti-locustamyotropin. In total, about 100 cells immunoreactive to the Lom-MT-II antiserum were detected in the head ganglia, in the abdominal neuromeres of the metathoracic ganglion, and in the five free abdominal ganglia. In the brain, immunoreactive cell groups were situated in the inner and outer edge of the tritocerebrum. Prominent axon bundles tightly surround the tractus I to the corpora cardiaca. The corpora allata were innervated by the nervus corporis allati I coming from the corpora cardiaca and by fibers in the nervus corporis allati II originating from cell bodies in the suboesophageal ganglion. Immunoreactive cell bodies in the suboesophageal and abdominal ganglia are distributed along the anterior posterior midline axis, both dorsally and ventrally. The processes of the cell bodies in the abdominal ganglia leave the ganglia and were traced in the respective median nerves into the neurohaemal organs. Since the Lom-MT-II antiserum cross-reacts with all peptides of the locustamyotropin family that have a carboxy-terminus in common, these cells may contain one or several locustamyotropins. The Lom-MT antiserum also recognizes pheromone biosynthesis activating neurohormone, as was revealed by the intensive labeling of suboesophageal cell bodies in Bombyx mori.

Amino Acid Sequence↗
PubMed1992

Locustakinin, a novel myotropic peptide from Locusta migratoria, isolation, primary structure and synthesis.

The isolated hindgut of the cockroach, Leucophaea maderae is a very efficient bioassay tool for the monitoring of certain structural types of insect myotropic peptides during HPLC purification. Using this detection system, a six residue peptide has been isolated from an extract of 9000 brain corpora cardiaca-corpora allata suboesophageal ganglion complexes of Locusta migratoria. Amino acid composition and sequence analysis combined with enzymatic digestion data established the structure of the novel peptide as Ala-Phe-Ser-Ser-Trp-Gly-amide. The chromatographic and biological properties of the synthetic peptide were the same as those of the native peptide, thus confirming structural analysis. The carboxy-terminal pentamer sequence is the active core of leucokinins II, V and VII and of achetakinin III (myotropic neuropeptides isolated from Leucophaea m. and from Acheta domesticus; Holman et al., 1990). Furthermore, the octapeptide leucokinin VII contains the novel sequence as its carboxy-terminal hexamer and Achetakinin V (AFHSWGamide) differs from it by one residue. This new peptide designated as locustakinin I (locusts) may therefore represent an evolutionary molecular link between leucokinin VII (cockroaches) and achetakinin V (crickets). Using synthetic locustakinin, physiological studies will be performed in the locust. In view of the known effects of leucokinins, locustakinin may be important in the stimulation of ion transport and inhibition of diuretic activity in Malpighian tubules. This study indicates that the AFXSWGamide sequence appears to have been well conserved and that members of this peptide family may be widely distributed among insects and posses a number of functions.

Amino Acid Sequence↗
PubMed1992

Localization of Lom-AG-myotropin I-like substances in the male reproductive and nervous tissue of the locust, Locusta migratoria.

Lom-AG myotropin I (Lom-AG-MTI) was the first peptide to be isolated from the male accessory reproductive glands of the locust, Locust migratoria. It shows no sequence similarity to any of the peptides identified from vertebrate or invertebrate tissues. A polyclonal antiserum was used to localize Lom-AG-MTI-like material in the male reproductive system and nervous system of the locust. Immunoreactivity was found in two of the hyaline gland tubules. In the brain, cell bodies were detected in the photo- and deuterocerebrum as well as the frontal ganglion. Nerve fibers were stained in the neuropils of the brain and throughout the labial nerves into the recurrent nerve. Thoracic and last abdominal ganglia contained neurons which could be stained with Lom-AG-MTI antiserum. The pronounced reactivity in the central nervous system suggests a possible neuroregulatory function of the peptide.

Amino Acid Sequence↗
PubMed1992

Isolation, primary structure and synthesis of neomyosuppressin, a myoinhibiting neuropeptide from the grey fleshfly, Neobellieria bullata.

1. An amidated decapeptide, showing strong inhibitory activity of spontaneous visceral muscle movement was isolated, from head extracts of 42 thousand fleshflies, Neobellieria bullata (Diptera, Sarcophagidae). 2. Amino acid sequencing and verification by peptide synthesis revealed the following primary structure: Thr-Asp-Val-Asp-His-Val-Phe-Leu-Arg-PheNH2. 3. The novel peptide was termed neomyosuppressin or Neb-MS. 4. During the process of consecutive high performance liquid chromatography (HPLC) purifications the biological activity of the samples was monitored using heterologous bioassay system. 5. The threshold level of synthetic Neb-MS was found to be 8.6 +/- 0.5 x 10(-11) M on the Leucophaea hindgut and 3.4 +/- 0.5 x 10(-10) M on the Locusta oviduct bioassay, respectively.

Amino Acid Sequence↗