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Yellow sac spiders ( Cheiracanthium punctorium, family Miturgidae) are unique in terms of venom composition, because, as we show here, two-domain toxins have replaced the usual one-domain peptides as the major constituents. We report the structure of the two-domain Che. punctorium toxins ( CpTx), along with the corresponding cDNA and genomic DNA sequences. At least three groups of insecticidal CpTx were identified, each consisting of several members. Unlike many cone snail and snake toxins, accelerated evolution is not typical of cptx genes, which instead appear to be under the pressure of purifying selection. Both CpTx modules present the inhibitor cystine knot ( ICK), or knottin signature; however, the sequence similarity between the domains is low. Conversely, notable similarity was found between separate domains of CpTx and one-domain toxins from spiders of the Lycosidae family. The observed chimerism is a landmark of exon shuffling events, but in contrast to many families of multidomain protein genes no introns were found in the cptx genes. Considering the possible scenarios, we suggest that an early transcription-mediated fusion event between two related one-domain toxin genes led to the emergence of a primordial cptx-like sequence. We conclude that evolution of toxin variability in spiders appears to be quite different from other venomous animals. [ABSTRACT FROM AUTHOR]

The article presents an abstract of the medical research paper "The Gene Structure of the α-Latrocrustatoxin From the Black Widow Spider Venom." The paper investigates the structural organization of genomic DNA encoding theα -latroinsectotoxin (α-LCT) from the spider venom to clarify whether the gene contains introns.

The article presents an abstract of the paper titled "Purification and cDNA Cloning of Novel Insecticidal Toxin From the Venom of the Scorpion Orthochirus Scrobiculosus." It investigates the insecticidal effect of scorpion venom on the larvae of Heliothis virescens. A new toxin OsI-1 was isolated from the venom which was found to be depressant type inhibiting the sodium channel.

The article presents an abstract of a research study which explains the age stage of locust with the highest level of glutamate receptor genes expression. Under the study, the membrane and cytosolic fractions from eggs of different growth stages, from nymph insects and from adult locust muscles were obtained. The study findings suggest that the expression of receptor genes occurs mainly at the first nymph stage.

The article presents an abstract of a research study that discusses the effect of the venom of ant toxins on cell membranes. The study was conducted particularly on two toxins called ectatomins (Et-1 and Et-2) obtained from the venom of Ectatomma tuberculazum ants. This study revealed that Et-1 more efficiently binds with Ca+2-channels compared to ectatomin Et-2.

The article presents an abstract of a research study on the mutagenesis of M-type K+ current named BeKm-1, which is composed of 36 amino acid residues along with a homology of other potassium channel blockers. Researchers believe that this BeKm-1 mutants will be significant for the characterization of the structure and pharmacological role of the M-channel.