Search results for "venom"
showing 10 items of 63 documents
Venom gland and reservoir morphology in the Doryctinae and related braconid wasps (Insecta, Hymenoptera, Braconidae)
1992
Detailed venom reservoir and venom gland intima morphology has been investigated in reprsentatives of 84 genera and 10 subfamilies of Braconidae with particular reference to the Doryctinac, basal cyclostomes and related groups including the Opiinae, Alysiinae and Rogadinae sens. lat. Several new phylogenetically significant characters are described and illustrated. Extcnsivc secretory ductules on the primary venom duct is suggested as a synapomorphy for the subfamilies Braconinac, Doryctinae, Opiinae, Alysiinae and Gnamptodontinae. The presence of two separate venom gland insertions and their position beyond the spiral sculpture of the reservoir are suggested as synapomorphies for the subfa…
A critical evaluation of caplacizumab for the treatment of acquired thrombotic thrombocytopenic purpura
2020
Introduction: Acquired thrombotic thrombocytopenic purpura (aTTP) is a thrombotic microangiopathy caused by inhibitory autoantibodies against ADAMTS13 protein. Until recently, the combination of plasma exchange (PEX) and immunosuppression has been the standard front-line treatment in this disorder. However, aTTP-related mortality, refractoriness, and relapse are still a matter of concern. Areas covered: The better understanding of the pathophysiological mechanisms of aTTP has allowed substantial improvements in the diagnosis and treatment of this disease. Recently, the novel anti-VWF nanobody caplacizumab has been approved for acute episodes of aTTP. Caplacizumab is capable to block the adh…
Insect venom immunotherapy induces interleukin-10 production and a Th2-to-Th1 shift, and changes surface marker expression in venom-allergic subjects.
1997
Abstract The current study was carried out to elucidate the immunoregulatory changes induced by venom immunotherapy (VIT) in bee or wasp allergic subjects. All subjects included in this study had a history of severe systemic allergic reactions to stings of the respective insect as well as positive skin tests with the respective venom or venom-specific IgE in the sera. Parameters assessed in peripheral blood mononuclear cells (PBMC) before and after initiation of VIT (rush therapy reaching a maintenance dose of 100 micrograms venom injected subcutaneously within 1 week) were expression of CD3, CD4, CD8, CD45RA, CD45RO, interleukin (IL)-2 receptor (R) alpha, IL-4R, IL-12R, Fc epsilon RII, CD4…
Haemolytic activity and characterization of nematocyst venom fromPelagia noctiluca(Cnidaria: Scyphozoa)
2013
We investigated the haemolytic capacity of the crude venom extracted from isolated nematocysts of Pelagia noctiluca (Cnidaria: Scyphozoa), and evidenced the proteic fractions responsible for this activity. The nematocyst venom was used at various concentrations to evaluate the haemolytic activity and the lysosomal membrane stability of red blood cells of two teleostean species treated with the extract. The nematocyst extract was assayed against erythrocytes of the two teleostean species living in different environments, Carassius auratus as a common freshwater species, and Liza aurata as a representative of seawater species. Experiments on the haemolytic activity of P. noctiluca in the pres…
Peptide–Membrane Interactions Monitored by Fluorescence Lifetime Imaging: A Study Case of Transportan 10
2021
The interest on detailed analysis of peptide-membrane interactions is of great interest in both fundamental and applied sciences as these may relate to both functional and pathogenic events. Such interactions are highly dynamic and spatially heterogeneous, making the investigation of the associated phenomena highly complex. The specific properties of membranes and peptide structural details, together with environmental conditions, may determine different events at the membrane interface, which will drive the fate of the peptide-membrane system. Here, we use an experimental approach based on the combination of spectroscopy and fluorescence microscopy methods to characterize the interactions …
Amino acid sequence and homology modeling of obtustatin, a novel non-RGD-containing short disintegrin isolated from the venom of Vipera lebetina obtu…
2003
Disintegrins represent a group of cysteine-rich peptides occurring in Crotalidae and Viperidae snake venoms, and are potent antagonists of several integrin receptors. A novel disintegrin, obtustatin, was isolated from the venom of the Vipera lebetina obtusa viper, and represents the first potent and selective inhibitor of the binding of integrin alpha(1)beta(1) to collagen IV. The primary structure of obtustatin contains 41 amino acids and is the shortest disintegrin described to date. Obtustatin shares the pattern of cysteines of other short disintegrins. However, in contrast to known short disintegrins, the integrin-binding loop of obtustatin is two residues shorter and does not express t…
Use of two-dimensional thin-layer chromatography for the components study of poly(adenosine diphosphate ribose)
1990
Two-dimensional thin-layer chromatography on cellulose plates has been used for separating and quantifying the three adenosine derivatives: AMP, phosphoribosyl AMP (PRAMP), and (PR)2AMP obtained by venom phosphodiesterase digestion of poly(ADP-ribose). In vitro synthesized polymer, up to 300 derivatives in length were studied. Some parameters of the complexity of poly(ADP-ribose) could be deduced from our results: (i) The first branching point appears in fragments of approximately 21 derivatives in length. (ii) The branching points are located at regular distances of approximately 41 derivatives from each other.
Formation and function of a complement-activating enzyme generated from factors of guinea pig serum and cobra venom
1971
An enzymatic complex can be formed by factors from guinea pig serum and cobra venom, which is able to activate C3 bypassing C1, C4 and C2. Formation and action of the enzyme are described. The action on C3 results in an activation of the terminal complement components and in membrane destruction provided suitable membrane receptors are available.
Uncapping the N-terminus of a ubiquitous His-tag peptide enhances its Cu2+ binding affinity
2019
Metal complexes with an N-terminally free and N-terminally acetylated polyhistidine region of Echis ocellatus venom, with an interesting His-rich motif present in numerous metal binding proteins from all kingdoms of life (DHDHDHHHHHHPGSSV-NH2 and Ac-DHDHDHHHHHHPGSSV-NH2) show the role of the free amino group in the thermodynamic enhancement of Cu2+, Ni2+ and Zn2+ binding. In the studied sequences, Cu2+ can be coordinated by different sets of imidazole rings, and a 3–10 helix is detected in close proximity of Cu2+ binding sites. The complexes are more stable than those with a typical His6-tag, despite a similar copper(II) coordination mode in both cases.
Comparison of the contractile effects of endothelin-1 and sarafotoxin S6b in goat isolated cerebral arteries
1992
1. The effects of endothelium-derived endothelin-1 and snake venom-derived sarafotoxin S6b, peptides with striking structural and functional similarities, were examined and compared in isolated middle cerebral arteries of goats. 2. Endothelin-1 and sarafotoxin S6b contracted cerebral arteries in a concentration-dependent manner. The potency of endothelin-1 (EC50 = 4.9 (3.9-6.2) x 10(-10) M) was about ten times higher than that of sarafotoxin S6b (EC50 = 5.5 (4.4-6.9) x 10(-9) M). The tension returned to basal values after repeated washings and contraction with endothelin-1 could be reproduced. Endothelin-1 and sarafotoxin S6b induced further contraction in arteries precontracted with prosta…