Cyanobacterial Cyclic Peptides Can Disrupt Cytoskeleton Organization in Human Astrocytes-A Contribution to the Understanding of the Systemic Toxicity of Cyanotoxins.

The systemic toxicity of cyclic peptides produced by cyanobacteria (CCPs) is not yet completely understood. Apart from the most known damages to the liver and kidneys, symptoms of their neurotoxicity have also been reported. Hepatotoxic CCPs, like microcystins, as well as non-hepatotoxic anabaenopeptins and planktopeptins, all exhibit cytotoxic and cytostatic effects on mammalian cells.

Reversible Thrombocytopenia of Functional Platelets after Nose-Horned Viper Envenomation Is Induced by a Snaclec.

Profound and transient thrombocytopenia of functional platelets without bleeding was observed in patients envenomed by (). This condition was rapidly reversed by administration of F(ab) fragments of immunoglobulin G targeting the whole venom, leaving platelets fully functional. To investigate the potential role of snake venom C-type lectin-like proteins (snaclecs) in this process, -snaclecs were isolated from the crude venom using different liquid chromatographies.

New insights into the effects of organometallic ruthenium complexes on nicotinic acetylcholine receptors.

Nicotinic acetylcholine receptors (nAChRs) are expressed in excitable and non-excitable cells of the organism. Extensive studies suggest that nAChR ligands have therapeutic potential, notably for neurological and psychiatric disorders. Organometallic ruthenium complexes are known to inhibit several medically important enzymes such as cholinesterases.

Advances in Cholinesterase Inhibitor Research-An Overview of Preclinical Studies of Selected Organoruthenium(II) Complexes.

Cholinesterase (ChE) inhibitors are crucial therapeutic agents for the symptomatic treatment of certain chronic neurodegenerative diseases linked to functional disorders of the cholinergic system. Significant research efforts have been made to develop novel derivatives of classical ChE inhibitors and ChE inhibitors with novel scaffolds. Over the past decade, ruthenium complexes have emerged as promising novel therapeutic alternatives for the treatment of neurodegenerative diseases.

Comparative electrophysiological characterization of ammodytoxin A, a β-neurotoxin from the nose-horned viper venom, and its enzymatically inactive mutant.

Presynaptic- or β-neurotoxicity of secreted phospholipases A (sPLA) is a complex process. For full expression of β-neurotoxicity, the enzymatic activity of the toxin is essential. However, it has been shown that not all toxic effects of a β-neurotoxin depend on its enzymatic activity, for example, the inhibition of mitochondrial cytochrome c oxidase.

Novel Organoruthenium(II) Complex C1 Selectively Inhibits Butyrylcholinesterase without Side Effects on Neuromuscular Transmission.

Enzyme butyrylcholinesterase (BChE) shows increased activity in some brain regions after progression of Alzheimer's disease and is therefore one of the therapeutic targets for symptomatic treatment of this neurodegenerative disorder. The organoruthenium(II) complex [(η--cymene)Ru(II)(1-hydroxy-3-methoxypyridine-2(1)-thionato)pta]PF () was designed based on the results of our previous structure-activity studies. Inhibitory activity toward cholinesterase enzymes shows that this complex selectively, competitively, and reversibly inhibits horse serum BChE (hsBChE) with an IC value of 2.

Fine Tuning of Cholinesterase and Glutathione-S-Transferase Activities by Organoruthenium(II) Complexes.

Cholinesterases (ChEs) show increased activities in patients with Alzheimer's disease, and remain one of the main therapeutic targets for treatment of this neurodegenerative disorder. A library of organoruthenium(II) complexes was prepared to investigate the influence of their structural elements on inhibition of ChEs, and on another pharmacologically important group of enzymes, glutathione S-transferases (GSTs). Two groups of organoruthenium(II) compounds were considered: (i) organoruthenium(II) complexes with -cymene as an arene ligand, and (ii) organoruthenium(II) carbonyl complexes as CO-releasing molecules.

Effects of Bioinsecticidal Aegerolysin-Based Cytolytic Complexes on Non-Target Organisms.

Aegerolysin proteins ostreolysin A6 (OlyA6), pleurotolysin A2 (PlyA2) and erylysin A (EryA) produced by the mushroom genus bind strongly to an invertebrate-specific membrane sphingolipid, and together with a protein partner pleurotolysin B (PlyB), form transmembrane pore complexes. This pore formation is the basis for the selective insecticidal activity of aegerolysin/PlyB complexes against two economically important coleopteran pests: the Colorado potato beetle and the western corn rootworm. In this study, we evaluated the toxicities of these aegerolysin/PlyB complexes using feeding tests with two ecologically important non-target arthropod species: the woodlouse and the honey bee.

The first Kunitz-type proteins from a viperid venom that potentiate neuromuscular transmission.

Kunitz-type proteins that interfere with neuronal transmission have been thus far exclusively detected in venoms of elapid snakes. Here, we report for the first time that such proteins are also present in the venom of a viperid snake. From the venom of the nose-horned viper (Vipera ammodytes ammodytes; Vaa), we isolated Kunitz-type chymotrypsin inhibitors (VaaChi) and demonstrated that these molecules also significantly increase the amplitudes of an indirectly evoked simple muscle contraction of the mouse hemidiaphragm, the end-plate potential and the miniature end-plate potential.

Structural and functional characterization of an organometallic ruthenium complex as a potential myorelaxant drug.

In addition to antibacterial and antitumor effects, synthetic ruthenium complexes have been reported to inhibit several medicinally important enzymes, including acetylcholinesterase (AChE). They may also interact with muscle-type nicotinic acetylcholine receptors (nAChRs) and thus affect the neuromuscular transmission and muscle function. In the present study, the effects of the organometallic ruthenium complex of 5-nitro-1,10-phenanthroline (nitrophen) were evaluated on these systems.

Organoruthenium Prodrugs as a New Class of Cholinesterase and Glutathione-S-Transferase Inhibitors.

A small library of 17 organoruthenium compounds with the general formula [Ru (fcl)(chel)(L)] (in which fcl=face capping ligand, chel=chelating bidentate ligand, and L=monodentate ligand) were screened for inhibitory activity against cholinesterases and glutathione-S-transferases of human and animal origins. Compounds were selected to include different chelating ligands (i.e.

Confocal micrographs: automated segmentation and quantitative shape analysis of neuronal cells treated with ostreolysin A/pleurotolysin B pore-forming complex.

Detailed shape analysis of cells is important to better understand the physiological mechanisms of toxins and determine their effects on cell morphology. This study aimed to develop a procedure for accurate morphological analysis of cell shape and use it as a tool to estimate toxin activity. With the aim of optimizing the method of cell morphology analysis, we determined the influence of ostreolysin A and pleurotolysin B complex (OlyA/PlyB) on the morphology of murine neuronal NG108-15 cells.

Short communication: Heat treatment and souring do not affect milk estrone and 17β-estradiol concentrations.

The aim of our study was to establish whether heat treatment and souring of milk affect its estrone (E1) and 17β-estradiol (E2) concentrations. Milk samples were collected from 10 Holstein cows in late pregnancy. Concentrations of E1 and E2 were measured in milk samples that were previously heated to 70 and 95°C for 5 min.

Natural polymeric 3-alkylpyridinium salt affects vertebrate skeletal muscle contractility by preferentially blocking neuromuscular transmission.

The effects of natural polymeric alkylpyridinium salt (nPoly-3-APS), a potent acetylcholinesterase inhibitor isolated from the marine sponge Reniera sarai, were studied on isolated mouse phrenic nerve-hemidiaphragm muscle preparations using electrophysiological approaches. nPoly-3-APS inhibited nerve-evoked isometric muscle twitch and tetanic contraction in a concentration-dependent manner (IC=29.4μM and 18.

Discorhabdin alkaloids from Antarctic Latrunculia spp. sponges as a new class of cholinesterase inhibitors.

The brominated pyrroloiminoquinone alkaloids discorhabdins B, L and G and 3-dihydro-7,8- dehydrodiscorhabdin C, isolated from methanol extracts of two specimens of Latrunculia sp. sponges collected near the Antarctic Peninsula, are here demonstrated for the first time to be reversible competitive inhibitors of cholinesterases. They showed K for electric eel acetylcholinesterase of 1.

Synthetic analogs of stryphnusin isolated from the marine sponge Stryphnus fortis inhibit acetylcholinesterase with no effect on muscle function or neuromuscular transmission.

The marine secondary metabolite stryphnusin (1) was isolated from the boreal sponge Stryphnus fortis, collected off the Norwegian coast. Given its resemblance to other natural acetylcholinesterase antagonists, it was evaluated against electric eel acetylcholinesterase and displayed inhibitory activity. A library of twelve synthetic phenethylamine analogs, 2a-7a and 2b-7b, containing tertiary and quaternary amines respectively were synthesized to investigate the individual structural contributions to the activity.

Venomics of Vipera berus berus to explain differences in pathology elicited by Vipera ammodytes ammodytes envenomation: Therapeutic implications.

Unlabelled: Vipera berus berus (Vbb) is the most widely distributed and Vipera ammodytes ammodytes (Vaa) the most venomous viper in Europe. In particular areas of the Old continent their toxic bites constitute a considerable public health problem. To make the current envenomation therapy more effective we have analysed the proteome of Vbb venom and compared it with that of Vaa.

Analysis of compound action potentials elicited with specific current stimulating pulses in an isolated rat sciatic nerve.

The ability to selectively stimulate Aα, Aβ-fibers and Aδ-fibers in an isolated rat sciatic nerve (SNR) was assessed. The stimulus used was a current, biphasic pulse with a quasitrapezoidal cathodic phase and rectangular anodic phase where parameters were systematically varied: intensity of the cathodic phase (ic); width of the cathodic phase (tc); width of the cathodic exponential decay (texp) and time constant of the exponential decay (τexp). A SNR was stimulated using a pair of hook electrodes while conduction velocity (CV) and compound action potentials (CAP) were measured at two sites along the SNR using another two pairs of electrodes.

Beauvericin Inhibits Neuromuscular Transmission and Skeletal Muscle Contractility in Mouse Hemidiaphragm Preparation.

The effects of Beauvericin (BEA) produced by the fungusBeauveria bassianaandFusariumsp. on neuromuscular transmission and contractility were determined in an isolated neuromuscular mouse hemidiaphragm preparation. BEA (5 µM) significantly inhibits indirectly elicited twitch amplitude.

Effect of the ostreolysin A/pleurotolysin B pore-forming complex on intracellular Ca2+ activity in the vascular smooth muscle cell line A10.

Ostreolysin A/pleurotolysin B (OlyA/PlyB) is a binary pore-forming protein complex that produces a rapid cardiorespiratory arrest. Increased tonus of the coronary vascular wall produced by OlyA/PlyB may lead to ischemia, arrhythmias, the hypoxic injury of cardiomyocytes and cardiotoxicity. We evaluated the effects of OlyA/PlyB in cultured vascular smooth muscle A10 cells.

Ostreolysin induces sustained contraction of porcine coronary arteries and endothelial dysfunction in middle- and large-sized vessels.

Ostreolysin (Oly), a cytolytic and cardiotoxic protein from the oyster mushroom (Pleurotus ostreatus), is lethal for mice with an LD(50) of 1170 microg/kg following intravenous application. Its cardiotoxicity is associated with hyperkalemia, which is probably a consequence of potassium released from the lysed cells. Moreover, sub-micromolar concentrations of Oly induce a concentration-dependent increase in rat aortic ring tension, suggesting that ischaemia, and consequent hypoxic injury of cardiomyocytes, could also derive from vasospasm induced by this toxic protein.

Toxic and lethal effects of ostreolysin, a cytolytic protein from edible oyster mushroom (Pleurotus ostreatus), in rodents.

Ostreolysin (Oly), an acidic, 15 kDa protein from the edible oyster mushroom (Pleurotus ostreatus), is a toxic, pore-forming cytolysin. In this paper, its toxic properties have been studied in rodents and the LD(50) in mice shown to be 1170 microg/kg. Electrocardiogram, arterial blood pressure and respiratory activity were recorded under general anaesthesia, in intact, pharmacologically vagotomised and artificially respirated rats injected with one mouse LD(50).

Microcystin-LR affects cytoskeleton and morphology of rabbit primary whole embryo cultured cells in vitro.

Microcystin-LR is the most frequently studied cyclic heptapeptide produced by different genera of cyanobacteria and is hepatotoxic to livestock and human populations. The adverse effects of microcystin-LR on morphology and cytoskeletal elements in different stages of early embryonal development have been studied in vitro. Embryos and whole embryo cultures have been exposed to microcystin-LR (10-100 microM).