Disease relevance of Melt

• Two species of full-length cDNA are synthesized in high yield by melittin-treated avian retrovirus particles [1].
• These results were compared to the effects of melittin, which has been reported to induce enzyme release and hemolysis [2].
• Experiments with the bee venom protein melittin, with the alpha-toxin of Staphylococcus aureus and with activated complement, show that the lesions produced by these agents, too, are sensitive to extracellular Ca2+ and to 'anti-Ca2+' drugs [3].
• Prior to recombination, each gene was cloned into the baculovirus transfer vector pVT-Bac, which permits insertion of the gene minus its natural signal peptide in frame with the signal peptide of honeybee melittin [4].
• A number of compounds would be able to inhibit HIV-1 gene expression at the transcription level: the flavonoid chrysin (through inhibition of casein kinase II, the antibacter ial peptides melittin (from bee venom) and cecropin, and EM2487, a novel substance produced by Streptomyces [5].

High impact information on Melt

• We describe here the primary structures of cecropins A and B. We also show that cecropin A is specific for bacteria in contrast to melittin, the main lytic component in bee venom which lyses both bacteria and eukaryotic cells [6].
• Succinyl bee venom melittin is a leukocyte chemotactic factor [7].
• The NH2-terminal amino acid sequence of the amoeba peptide was determined by protein sequencing and revealed a structural similarity to melittin, the membranolytic peptide of bee venom [8].
• Twenty micrograms of bee venom melittin, which activates endogenous phospholipase A2, administered intracisternally into rabbits also produced signs of level 3 (our grading system) coma for several hours [9].
• Translation of melittin messenger RNA from queen bee venom glands in a cell-free system from wheat germ yielded prepromelittin [10].

Chemical compound and disease context of Melt

• The RNP structure was not observed in unphosphorylated virions treated with melittin and uranyl acetate [11].
• The results showed that both pre- and post-treatment of capsazepine could significantly prevent and suppress the melittin-induced ongoing nociceptive responses and thermal hypersensitivity, but were without influencing mechanical hypersensitivity [12].
• Activation of the VSV virion kinase with low concentrations of melittin, the active peptide component of bee venom, in the presence of gamma-[32P] ATP resulted in the phosphorylation of virion proteins [11].
• Following the in vitro phosphorylation of VSV proteins in the presence of melittin and deoxyadenosine triphosphate, the virion envelope was disrupted based on the accessibility of the internal ribonucleoprotein core (RNP) to the heavy metal stain, uranyl acetate, as determined by electron microscopic observation [11].
• A comparison of hyperalgesia and neurogenic inflammation induced by melittin and capsaicin in humans [13].

Biological context of Melt

• Influence of the lipid composition on the kinetics of concerted insertion and folding of melittin in bilayers [14].
• The inhibitory effects of BV and melittin on inflammatory gene expression were measured by Western blotting, and the generation of prostaglandin E(2) (PGE(2)) and nitric oxide (NO) and the intracellular calcium level were assayed [15].
• However, competitive binding studies suggest that all three monoclonal Ig bind at the same, or adjacent, site of melittin [16].
• Mastoparan and polymyxin B were much less inhibitory (IC50, 10-20 microM), whereas melittin and cardiotoxin were similarly inhibitory (IC50, 1-4 microM), when protein kinase C was activated instead by synaptosomal membrane [17].
• Antibody responses to bee melittin (Api m 4) and hornet antigen 5 (Dol m 5) in mice treated with the dominant T-cell epitope peptides [18].

Anatomical context of Melt

• The organization of membrane-bound melittin is dependent on the physical state and composition of membranes [19].
• Scanning electron micrographs of the intimal surface demonstrated that melittin and polyarginine greatly damaged the endothelial cells [20].
• Removal of the endothelium prevented the increased levels of cyclic GMP and cyclic AMP due to melittin [20].
• Bombolitin V is as potent as the well-known melittin in lysing guinea pig erythrocytes (ED50 = 0.7 microgram/ml = 4 X 10(-7) M) and is 5 times more potent than mastoparan in causing mast cell degranulation, making it one of the most potent degranulating peptides discovered so far (ED50 = 2 micrograms/ml = 1.2 X 10(-6) M) [21].
• These immunochemical observations suggest that the immunogenicity of melittin or its analogues is a consequence of its binding to cell membranes with subsequent oligomer formation in lipid bilayers [22].

Associations of Melt with chemical compounds

• For all the investigated membrane systems (cholesterol-containing, phosphoglycerol-containing, and pure phosphocholine bilayers), the decrease in the polarity of 19Trp was found to be significantly faster than the increase in the helical content of melittin [14].
• Our results show that fluorescence parameters such as intensity, emission maximum, polarization, lifetime and acrylamide quenching of melittin incorporated in membranes are dependent on the degree of unsaturation of lipids in membranes [19].
• Relaxations to melittin, and to the endothelium-dependent vasodilators acetylcholine, trypsin, histamine, and the Ca2+ ionophore A23187, and/or the associated increased cyclic GMP levels, were reduced following exposure to melittin [20].
• Effects of melittin on endothelium-dependent relaxation and cyclic GMP levels in rat aorta [20].
• Methylene blue, nordihydroguaiaretic acid, and the phospholipase A2 inhibitor, parabromophenacyl bromide, inhibited melittin-induced relaxations, while the cyclo-oxygenase inhibitor, indomethacin, was without effect [20].

Physical interactions of Melt

• We suggest that melittin binds to the hydrophobic site of acetylcholinesterase which anchors it in the lipid bilayer [23].

Regulatory relationships of Melt

• These studies do not support the suggestion that snake venom cardiotoxins and melittin selectively activate endogenous phospholipase A2 activity [24].
• The melittin-induced Ca(2+) influx was unchanged by modulation of protein kinase-C activity with phorbol 12-myristate 13-acetate (PMA) and GF 109203X, or inhibition of phospholipase A(2) with AACOCF(3) and aristolochic acid; but was substantially inhibited by blocking L-type Ca(2+) channels [25].

Other interactions of Melt

• The sequences are given of two peptides (secapin and melittin F) whose isolation from the venom of the common European honey bee (Apis mellifera) has previously been described [Gauldie et al. (1976) Eur. J. Biochem. 61, 369--376] [26].
• The same relative inhibitory potencies of the polypeptides (melittin greater than mastoparan greater than polymyxin B) for inhibition of Na,K-ATPase were also noted for their inhibition of Ca2+/calmodulin-dependent protein kinase II, 86Rb uptake (Na+ pump) by HL60 cells and the phorbol ester-induced differentiation of the leukemia cells [17].
• Compounds investigated include corticotropin and melittin derivatives, mast-cell-degranulating peptide from bee venom, polymyxin B, bradykinin and various synthetic poly(amino acids) and short-chain peptides [27].
• Phospholipase A, acid phosphatase, hyaluronidase and melittin were demonstrated in the immunoprecipitates using zymographic techniques and direct hemolysis of sheep erythrocytes [28].
• Among the venom constituents, only melittin caused contractile and morphological effects; other peptides, such as apamin and mastparan; enzymes, such as phospholipase A2; and low-molecular-weight compounds, such as histamine and dopamine, did not [29].

Analytical, diagnostic and therapeutic context of Melt

• Crystallized melittin retains its lytic activity even under the conditions of crystallization (about 70% saturated ammonium sulfate) [30].
• Cooperative effects in the interaction between melittin and phosphatidylcholine model membranes. Studies by temperature scanning densitometry [31].
• We used circular dichroism (CD) to compare the effects of various alcohols on melittin [32].
• Venom from each of these bees was studied with isoelectric focusing and functional assays for phospholipase A2 and melittin [33].
• The presence of serum IgE antibodies to melittin was tested by the radioallergosorbent test (RAST) [34].

References