Loxosceles rufescens, commonly known as the Mediterranean Recluse or Mediterranean Fiddle-Back Spider is recorded from Iran for the first time. The genus Loxosceles contains 103 accepted species, two of them (including L. rufescens) are cosmopolitan. All Loxosceles species tested so far possess necrotic venoms, which is a unique characteristic among the Order Araneae. Considering this character...

Toxins isolated from scorpion, snake, and spider venoms are valuable tools to probe the physiologic function and structure of ion channels. In this study, we have isolated three new toxins (heteropodatoxins) from the venom of a spider, Heteropoda venatoria. These toxins are structurally similar peptides of 29 to 32 amino acids and share sequence homology with hanatoxins isolated from the venom ...

aims: venomous snake bites are public health problems in different parts of the world. the most specific mainstay in the treatment of envenomation is anti-venom. to treat the envenomation, it is very important to identify the offending species. this study was designed to determine the penetrating pattern of fangs and teeth of some viper snakes.  materials & methods: this descriptive study was p...

A modification of the classical procedure of fluctuation analysis is used to measure the waveform, w(t), mean amplitude, (h), and mean rate of occurrence, (r), of miniature endplate potentials (MEPPs) at frog cutaneous pectoris neuromuscular junctions treated with black widow spider venom (BWSV). MEPP parameters are determined from the power spectrum of the fluctuating potential and the second ...

The voltage-gated sodium (Na(v)) channel is a target for a number of drugs, insecticides and neurotoxins. These bind to at least seven identified neurotoxin binding sites and either block conductance or modulate Na(v) channel gating. A number of peptide neurotoxins from the venoms of araneomorph and mygalomorph spiders have been isolated and characterized and determined to interact with several...

Eight linear cationic peptides with cytolytic and insecticidal activity, designated cyto-insectotoxins (CITs), were identified in Lachesana tarabaevi spider venom. The peptides showed antibiotic activity towards Gram-positive and Gram-negative bacteria at micromolar concentrations as well as toxicity to insects. The primary structures of the toxins were established by direct Edman sequencing in...

We have identified a 35 amino acid peptide toxin of the inhibitor cysteine knot family that blocks cationic stretch-activated ion channels. The toxin, denoted GsMTx-4, was isolated from the venom of the spider Grammostola spatulata and has <50% homology to other neuroactive peptides. It was isolated by fractionating whole venom using reverse phase HPLC, and then assaying fractions on stretch-ac...

D-amino acids have been detected in a variety of peptides synthesized by animal cells. These include opiate and antimicrobial peptides from amphibian skin, neuropeptides from snail ganglia, a hormone from crustaceans, and a constituent of a spider venom. cDNA cloning has shown that at those positions where a D-amino acid is found in the end-product, a normal codon for the corresponding L-amino ...

Membrane proteins have been isolated from neuromuscular synapses of the crab Potamon transcaspicum using a specific blocker of glutamatergic synapses, the neurotoxin of the spider Argiope lobata. These membrane components have been shown to induce glutamate-sensitive conductance in bilayer lipid membranes (BLM) in the presence of sodium ions. As an agent blocking desensitization of glutamatergi...