The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Ciguatera is a global disease caused by the consumption of certain warm-water fish (ciguateric fish) that have accumulated orally effective levels of sodium channel activator toxins (ciguatoxins) through the marine food chain. Symptoms of ciguatera include a range of gastrointestinal, neurological and cardiovascular disturbances. This review examines progress in our understanding of ciguatera from...
β-Bungarotoxin from the Taiwan banded krait, Bungarus multicinctus is a basic protein (pI=9.5), with a molecular weight of 21,800 consisting of two different polypeptide subunits. A phospholipase A 2 subunit named the A-chain and a non-phospholipase A 2 subunit named the B-chain, which is homologous to Kunitz protease inhibitors. The A-chain and the B-chain are covalently linked by...
In most tissues, including brain, a major proportion of the tryptophan which is not used for protein synthesis is metabolised along the kynurenine pathway. Long regarded as the route by which many mammals generate adequate amounts of the essential co-factor nicotinamide adenine dinucleotide, two components of the pathway are now known to have marked effects on neurones. Quinolinic acid is an agonist...
Dendrotoxins are small proteins that were isolated 20 years ago from mamba (Dendroaspis) snake venoms (Harvey, A.L., Karlsson, E., 1980. Dendrotoxin from the venom of the green mamba, Dendroaspis angusticeps: a neurotoxin that enhances acetylcholine release at neuromuscular junctions. Naunyn-Schmiedebergs Arch. Pharmacol. 312, 1-6.). Subsequently, a family of related proteins was found in mamba venoms...
Animals acquire toxicity either by metabolic synthesis of toxins (secondary metabolites), by expression of toxin genes or by the uptake, storage and sequestration of toxins produced by other organisms, i.e., microbes, plants or other animals. Variability of toxin structure and function is high. Peptide toxins in particular, although relying on a limited number of structural frameworks, often exhibit...
The cystine knot structural motif is present in peptides and proteins from a variety of species, including fungi, plants, marine molluscs, insects and spiders. It comprises an embedded ring formed by two disulfide bonds and their connecting backbone segments which is threaded by a third disulfide bond. It is invariably associated with nearby β-sheet structure and appears to be a highly efficient motif...
The neuroparalytic syndromes of tetanus and botulism are caused by neurotoxins produced by bacteria of the genus Clostridium. They are 150 kDa proteins consisting of three-domains, endowed with different functions: neurospecific binding, membrane translocation and specific proteolysis of three key components of the neuroexocytosis apparatus. After binding to the presynaptic membrane of motoneurons,...
Currently, no effective therapy has been approved for the treatment of addiction to stimulant drugs (e.g., cocaine, amphetamine and its methylated derivatives). However, preclinical studies indicate that the naturally-occurring indole alkaloid, ibogaine, and a synthetic iboga alkaloid congener, 18-methoxycoronaridine (18-MC), attenuate stimulant self-administration in laboratory animals. The in vivo...
A comparison of the toxinological properties of nematocyst venoms from Old and New World Cassiopea and Aurelia species was undertaken. The cnidom of venomous Cassiopea andromeda (Ca) and Aurelia (Aa RS ) from the Red Sea was identical to that of nonvenomous Bahamian Cassiopea xamancha (Cx) and Chesapeake Bay Aurelia aurita (Aa CB ), respectively. A clean nematocyst preparation...
The low molecular mass fraction of the venom of the spider Latrodectus menavodi, a black widow spider domiciled in Madagascar, was analyzed with HPLC combined with electrospray mass spectrometry as lyophilized powder and as freshly milked liquid venom. The main components were found to be the purine derivatives adenosine (1), guanosine (2), inosine (3), and 2,4,6-trihydroxypurine (4). Compounds 1-3...
A unique (lethal-cardiotoxic-hemorrhagic) protein toxin (Toxin CM55) was isolated and purified from Indian King Cobra (Ophiophagus hannah) venom by CM-sephadex ion exchange chromatography and reverse phase HPLC. The purified toxin had an SDS-molecular weight of 22 +/- 0.5 kD. UV absorption spectra of Toxin CM55 showed a peak at 280 nm, whereas when excited at 280 nm fluorescence, Toxin CM55 showed...
The diarrhetic shellfish toxin, okadaic acid, administered to rats by intragastric intubation, caused intestinal damage, diarrhea and death, but had no detectable effect on the liver. In contrast, okadaic acid administered intravenously had little effect on intestinal function, but caused a rapid dissolution of hepatic bile canalicular actin sheaths, congestion of blood in the liver, hypotension and...
Saxiphilin is a hydrophilic protein with a high affinity and specificity for paralytic shellfish toxins (PSTs) found in the circulatory fluid of many invertebrates and ectothermic vertebrates. Saxiphilin has been found to be closely related to the iron binding transferrins, a group of proteins that range in molecular weight between 70 and 90 kDa. One saxiphilin isoform, that from the centipede Ethmostigmus...
Bothrops lanceolatus venom contains caseinolytic, phospholipase, esterase and haemorrhagic activities. We have investigated the coagulant and anticoagulant actions of B. lanceolatus venom on human citrated plasma and on purified plasma components. Although B. lanceolatus venom up to 50 μg/ml was unable to clot citrated plasma, at concentrations =<5 μg/ml the venom dose-dependently clotted purified...
Shiga toxins share with plant ribosome-inactivating proteins the same enzymatic mechanism of action: the removal of a specific adenine from 28S RNA when acting on ribosomes and the removal of multiple adenines when acting on DNA in vitro. The activity on DNA, only recently reported, is particularly evident, and has been studied mostly at acidic pH. For the in vitro activity, on both ribosomes and...
By studying the influence of two toxins from the black mamba Dendroaspis polylepis on the kinetics of [ 3 H]-N-methylscopolamine binding to muscarinic acetylcholine receptors from rat cerebral cortex, it was revealed that these toxins, MTα and MTβ, interact with the receptors via kinetically distinct mechanisms. MTβ bound to receptors in a one-step, readily reversible process with the dissociation...
The homodimeric disintegrin contortrostatin was compared directly to the monomeric disintegrins echistatin and flavoridin for the ability to affect protein tyrosine phosphorylation in tumor cells. It was observed that contortrostatin had a dramatic effect on the tyrosine phosphorylation status of several proteins in T24 human bladder cancer cells, including robust induction of phosphorylation of proteins...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.