Callitachykinin I and II, two novel myotropic peptides isolated from the blowfly, Calliphora vomitoria, that have resemblances to tachykinins.

Two peptides, related to the locust myotropic peptides locustatachykinin I-IV, were isolated from the blowfly Calliphora vomitoria. Whole, frozen flies were used for extraction with acidified methanol. A cockroach hindgut muscle contraction bioassay was used for monitoring fractions during subsequent purification steps.

Characterization of an antiserum against an achetakinin I-analog and its use for the localization of Culekinin Depolarizing Peptide II in the mosquito, Culex salinarius.

ELISA experiments revealed that an antiserum raised against an achetakinin-analog could specifically detect the recently isolated Culekinin Depolarizing Peptide (CDP)-II from the mosquito, Culex salinarius. The characterization indicated that two different epitopes in the C-terminal region of achetakinin I and CDP-II are recognized. One epitope is the -F-Y-region, the other is the -P-W-region.

Hypercoagulable states.

Purpose: To describe the major pathophysiologic mechanisms underlying inherited and secondary hypercoagulable states and to evaluate the frequency, natural history, diagnosis, and management of the various clinical disorders.

Data Sources And Study Selection: Relevant clinical literature obtained from bibliographies in hematology textbooks and from computerized indexes was reviewed. A hypothesis was formed based on this literature review and on recent developments from a number of experimental studies.

Acyl, pseudotetra-, tri- and dipeptide active-core analogs of insect neuropeptides.

Pseudopeptides of the achetakinin insect neuropeptide family were synthesized by replacing the amino acid blocks Phe-, Phe-Tyr-, and Phe-Tyr-Pro- of the active-core pentapeptide Phe-Tyr-Pro-Trp-Gly-NH2 with hydrocinnamic acid, 6-phenylhexanoic acid, and both 9-phenylnonanoic and 6-phenylhexanoic acid, respectively. All four of these analogs retained myotropic activity, demonstrating that the active core could be reduced from a pentapeptide to a modified dipeptide. Most notable of these was the pseudotetrapeptide hydrocinnamyl-Tyr-Pro-Trp-Gly-NH2, which retained 70% of the potency and over 85% of the maximal activity of the parent pentapeptide.

Silkworm diapause induction activity of myotropic pyrokinin (FXPRLamide) insect neuropeptides.

A family of myotropic neuropeptides sharing the common C-terminal pentapeptide Phe-Xxx-Pro-Arg-Leu-NH2 (Xxx = Ser, Thr, Val), known as the pyrokinins, has been isolated from the cockroach Leucophaea maderae and locust Locusta migratoria of the order Orthoptera. A hormone (Bom-DH) that elicits diapause induction in the silkworm Bombyx mori (order Lepidoptera) also contains this C-terminal pentapeptide (Xxx = Gly). The orthopteran pyrokinin neuropeptides elicit significant diapause-inducing activity in the lepidopteran silkworm.

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.

Structure-activity relationships for inhibitory insect myosuppressins: contrast with the stimulatory sulfakinins.

Unusual among insect neuropeptides, the decapeptide myosuppressins are capable of inhibiting contractions of visceral muscle, including the isolated cockroach hindgut. The C-terminal pentapeptide Val-Phe-Leu-Arg-Phe-NH2 has been identified as the myosuppressin active core, the minimum number of residues required to elicit hindgut myoinhibitory activity. Activity of the same magnitude as the parent neuropeptide requires the C-terminal heptapeptide fragment Asp-His-Val-Phe-Leu-Arg-Phe-NH2.

Active conformation of the pyrokinin/PBAN neuropeptide family for pheromone biosynthesis in the silkworm.

Members of the pyrokinin/pheromone biosynthesis activating neuropeptide family elicit pheromonotropic activity in at least two species of moths. We report that in the silkworm (Bombyx mori) the conformationally constrained octapeptide analog cyclo[Asn-Thr-Ser-Phe-Thr-Pro-Arg-Leu] retains 10% of the pheromonotropic activity of naturally occurring Bom-PBAN-I, a 33 amino acid peptide. Previous data from CD, NMR, and molecular dynamics analyses indicate a type I beta-turn conformation for active core residues Thr-Pro-Arg-Leu in the cyclic analog.

Leads for insect neuropeptide mimetic development.

Insect neuropeptides mediate a number of physiological processes critical for insect survival. The numerous neuropeptide sequences that have been reported present an opportunity to decipher the chemical and conformational requirements for neuropeptide-receptor interactions. Chemical and conformational requirements for activity represent a "template" from which agonist/antagonist peptide mimetics, with the potential to disrupt critical insect processes, can be developed.

A bifunctional heterodimeric insect neuropeptide analog.

The synthesis and biological activity of a bifunctional, heterodimeric insect neuropeptide analog are described. The heterodimer is composed of the C-terminal pentapeptide active core regions of the leucokinin/achetakinin and pyrokinin neuropeptide families linked via their N-terminal amino groups with a succinyl diacid moiety. Members of the leucokinin/achetakinin family can induce fluid secretion in malpighian tubules of the house cricket, Acheta domesticus, whereas the pyrokinins demonstrate activity in a cricket oviduct myotropic bioassay.

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.

Thrombospondin sequence motif (CSVTCG) is responsible for CD36 binding.

To clarify the role of CD36 as a TSP receptor and to investigate the mechanisms of the TSP-CD36 interaction, transfection studies were performed using CD36-cDNA in a CDM8 plasmid. Jurkat cells transfected with CD36 cDNA express an 88kD membrane surface protein and acquire the ability to bind thrombospondin. The TSP amino acid sequence, CSVTCG, mediates the interaction of thrombospondin with CD36.

Isolation, identification and synthesis of locustamyoinhibiting peptide (LOM-MIP), a novel biologically active neuropeptide from Locusta migratoria.

A novel peptide termed locustamyoinhibiting peptide (LOM-MIP) was isolated from brain-corpora cardiaca-corpora allata-suboesophageal ganglion extracts of the locust, Locusta migratoria. The primary structure of this nonapeptide has been determined Ala-Trp-Gln-Asp-Leu-Asn-Ala-Gly-Trp-NH2. LOM-MIP suppresses the spontaneous contractions of the hindgut and oviduct of Locusta migratoria and of the hindgut of Leucophaea maderae.

Active conformation of an insect neuropeptide family.

To understand the structural and chemical basis for insect neuropeptide activity, we have designed, synthesized, and determined the conformation of a biologically active cyclic analog of the pyrokinins, an insect neuropeptide family that mediates myotropic (visceral muscle contractile) activity. Members of this insect neuropeptide family share the common C-terminal pentapeptide sequence Phe-Xaa-Pro-Arg-Leu-NH2 (Xaa = Ser, Thr, or Val). Circular dichroic, nuclear magnetic resonance, and molecular dynamics analyses of the conformationally restricted cyclic pyrokinin analog cyclo(-Asn-Thr-Ser-Phe-Thr-Pro-Arg-Leu-) indicated the presence of a beta-turn in the active core region encompassing residues Thr-Pro-Arg-Leu.

An active pseudopeptide analog of the leucokinin insect neuropeptide family.

A pseudopeptide analog of the active core of the leucokinin insect neuropeptide family was synthesized and found to retain myotropic activity. No reports of active pseudopeptide analogs of an insect or other invertebrate neuropeptide have previously appeared in the literature. The pseudopeptide (Phe psi [CH2-NH] Phe-Ser-Trp-Gly-NH2) contains a reduced-amide linkage between the two N-terminal Phe residues.

Lipoprotein (a) regulates plasminogen activator inhibitor-1 expression in endothelial cells. A potential mechanism in thrombogenesis.

Lipoprotein (a) (Lp(a)) is a low density lipoprotein-like particle which contains the plasminogen-like apolipoprotein a. Lp(a) levels are elevated in patients with atherosclerotic coronary artery disease. Recent studies suggest that Lp(a) competitively inhibits plasminogen binding to the endothelial cell and interferes with surface-associated plasmin generation.

Cellular attachment to thrombospondin. Cooperative interactions between receptor systems.

Tumor cell attachment to thrombospondin (TSP) in the extracellular matrix may be of critical importance in the processes of invasion and hematogenous dissemination. To determine the specific receptor systems that mediate the interaction of tumor cells with insoluble TSP, the attachment of HT1080 fibrosarcoma and C32 and G361 melanoma cells to TSP-coated discs was studied in the presence of heparin, Arg-Gly-Asp-Ser, or antibodies to glycoprotein (GP) IV (CD36, GPIIIb), a TSP receptor. HT1080 and C32 cell attachment to TSP was inhibited by the combination of heparin and a monoclonal (or polyclonal) antibody to GPIV but not by either alone.

Isolation, primary structure, and synthesis of locustapyrokinin: a myotropic peptide of Locusta migratoria.

A neuropeptide which stimulates the motility of the cockroach hindgut has been isolated from an extract of 9000 brain-corpora cardiaca-corpora allata-subesophageal ganglion complexes of 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 a blocked 16-residue peptide: pGlu-Asp-Ser-Gly-Asp-Gly-Trp-Pro-Gln-Gln-Pro-Phe-Val-Pro-Arg-Leu-NH2.

Endothelial cell fibrinolytic assembly.

Endothelial cells play a critical role in thromboregulation by controlling the assembly of fibrinolytic constituents on the membrane. The assembly system illustrated in FIGURE 6 is characterized by the binding of circulating glu-plasminogen to a membrane receptor (Pathway 1). A membrane-associated protease (possibly plasmin) converts the inactive zymogen into a catalytically more efficient zymogen lys-plasminogen (Pathway 2).

Lipoprotein(a) in diet-induced atherosclerosis in nonhuman primates.

Lipoprotein(a) (Lp[a]) is a low density lipoprotein particle that contains plasminogen-like apolipoprotein(a). Recent studies suggest an association of Lp(a) with atherosclerotic vascular disease. We have studied the accumulation of Lp(a) in atherosclerotic arteries of monkeys with diet-induced atherosclerosis.

Locustatachykinin III and IV: two additional insect neuropeptides with homology to peptides of the vertebrate tachykinin family.

Two myotropic peptides termed locustatachykinin III and IV were isolated from 9000 brain-corpora cardiaca-corpora allata-suboesophageal ganglion extracts of the locust, Locusta migratoria. The primary structures of Lom-TK III and IV were established as amidated decapeptides: Ala-Pro-Gln-Ala-Gly-Phe-Tyr-Gly-Val-Arg-NH2 (Lom-TK III) and Ala-Pro-Ser-Leu-Gly-Phe-His-Gly-Val-Arg-NH2 (Lom-TK IV). The locustatachykinins were synthesized and shown to have chromatographic and biological properties identical with those of the native materials.

Cytokine-enhanced expression of glycoprotein Ib alpha in human endothelium.

Platelet glycoprotein Ib is a major platelet membrane protein composed of two disulfide-linked chains, termed the alpha and beta chains. The larger alpha chain (GpIb alpha), a platelet receptor for von Willebrand factor, plays a major role in mediating platelet adhesion to the subendothelium. Our laboratories have previously reported synthesis of a protein in human endothelial cells that is immunoprecipitated with polyclonal and monoclonal antibodies to platelet GpIb alpha.