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PubMed1988

[Scorpions and scorpion stings in Jordan].

The scorpion fauna of Jordan consists of fourteen species belonging to three families (Buthidae, Scorpionidae and Diplocentridae), of which three species are poisonous: Leiurus quinquestriatus, Adroctonus crassicauda and Buthus occitanus. A key to all species is included. Five hundred and forty-seven cases of scorpion stings were reported during 1982-1985, including two fatalities. Clinical data for sixteen cases treated at the Jordan University Hospital are summarized. In Jordan human and cultural customs are related to scorpion stings. Sting accidents according to age groups and seasons are given.

Adolescent↗

PubMed1995

Black scorpion (Heterometrus longimanus) as a laboratory animal: maintenance of a colony of scorpion for milking of venom for research, using a restraining device.

Scorpion venom is a rich source of many proteins and peptides. A method for collection of venom from scorpions using a restraining device is being described. The details and measurement of the restraining device as well as that of the current used are described.

Animals↗

PubMed1978

Review of Southern African scorpions and scorpionism.

Medically important scorpions are discussed in terms of their venom, methods of envenomation and distribution in relation to the pattern of human population density dispersal. Notes on the treatment of scorpion sting and the identification of important species are provided.

Animals↗

PubMed2002

Characterization of scorpion alpha-like toxin group using two new toxins from the scorpion Leiurus quinquestriatus hebraeus.

Two novel toxins, Lqh6 and Lqh7, isolated from the venom of the scorpion Leiurus quinquestriatus hebraeus, have in their sequence a molecular signature (8Q/KPE10) associated with a recently defined group of alpha-toxins that target Na channels, namely the alpha-like toxins [reviewed in Gordon, D., Savarin, P., Gurevitz, M. & Zinn-Justin, S. (1998) J. Toxicol. Toxin Rev. 17, 131-159]. Lqh6 and Lqh7 are highly toxic to insects and mice, and inhibit the binding of alpha-toxins to cockroach neuronal membranes. Although they kill rodents by intracerebroventricular injection, they do not inhibit the binding of antimammal alpha-toxins (e.g. Lqh2) to rat brain synaptosomes, not even at high concentrations. Furthermore, in voltage-clamp experiments, rat brain Na channels IIA (rNav1.2A) expressed in Xenopus oocytes are not affected by Lqh6 nor by Lqh7 below 3 micro m. In contrast, muscular Na channels (rNav1.4 and hNav1.5) expressed in the same cells respond to nanomolar concentrations of Lqh6 and Lqh7 by slowing of Na current inactivation and a leftward shift of the peak conductance-voltage curve. The structural and pharmacological properties of the new toxins are compared to those of other scorpion alpha-toxins in order to re-examine the hallmarks previously set for the alpha-like toxin group.

Amino Acid Sequence↗

PubMed1996

Solution structure of P01, a natural scorpion peptide structurally analogous to scorpion toxins specific for apamin-sensitive potassium channel.

The venom of the North African scorpion Androctonus mauretanicus mauretanicus possesses numerous highly active neurotoxins that specifically bind to various ion channels. One of these, P05, has been found to bind specifically to calcium-activated potassium channels and also to compete with apamin, a toxin extracted from bee venom. Besides the highly potent ones, several of these peptides (including that of P01) have been purified and been found to possess only a very weak, although significant, activity in competition with apamin. The amino acid sequence of P01 shows that it is shorter than P05 by two residues. This deletion occurs within an alpha-helix stretch (residues 5-12). This alpha-helix has been shown to be involved in the interaction of P05 with its receptor via two arginine residues. These two arginines are absent in the P01 sequence. Furthermore, a proline residue in position 7 of the P01 sequence may act as an alpha-helix breaker. We have determined the solution structure of P01 by conventional two-dimensional 1H nuclear magnetic resonance and show that 1) the proline residue does not disturb the alpha-helix running from residues 5 to 12; 2) the two arginines are topologically replaced by two acidic residues, which explains the drop in activity; 3) the residual binding activity may be due to the histidine residue in position 9; and 4) the overall secondary structure is conserved, i.e., an alpha-helix running from residues 5 to 12, two antiparallel stretches of beta-sheet (residues 15-20 and 23-27) connected by a type I' beta-turn, and three disulfide bridges connecting the alpha-helix to the beta-sheet.

Amino Acid Sequence↗

PubMed1999

An nmr conformational analysis of a synthetic peptide Cn2(1-15)NH2-S-S-acetyl-Cn2(52-66)NH2 from the New World Centruroides noxius 2 (Cn2) scorpion toxin: comparison of the structure with those of the Centruroides scorpion toxins.

The solution structure of a synthetic peptide, Cn2(1-15)NH2-S-S-acetyl-Cn2(52-66)NH2 from toxin 2 (Cn2) of the New World scorpion Centruroides noxius was determined using nmr and molecular dynamics calculations. The peptide has no significant secondary structure such as an alpha-helix or a beta-sheet, yet it has a fixed conformation for the first chain. The backbone secondary structure involving residues 6-12 in this peptide shows an excellent overlap with the structures of natural neurotoxins from Centruroides sculpturatus Ewing. Residues 6-9 form a distorted type I beta-turn and residues 10-12 form a gamma-turn. As residues 7-10 in the Centruroides toxins correspond to one of the regions of highest sequence variability, it may account for the species specificity and/or selectivity of toxic action. The conformation of this region evidently plays an important role in receptor recognition and in binding to the neutralizing monoclonal antibody BCF2 raised against the intact toxin.

Amino Acid Sequence↗

PubMed2001

Egg maturation and parthenogenetic recovery of diploidy in the scorpion Liocheles australasiae (Fabricius) (Scorpions, ischnuridae).

In the scorpion Liocheles australasiae, egg maturation and parthenogenetic recoveries of chromosome number and nuclear DNA content were examined by histological, karyological observations and quantitative measurements of DNA. The primary oocyte becomes mature through two successive maturation divisions. The first maturation division takes place in the primary oocyte to produce a secondary oocyte and a first polar body. The second maturation division soon occurs in the secondary oocyte, in which the nucleus is divided into a mature egg nucleus and a second polar body nucleus, not followed by cytoplasmic fission. The first polar body, in one case, was successively divided into two second polar bodies; in the other case it was not divided. In either case, these polar bodies remained attached to the early embryo. The fate of these polar bodies during further embryogenesis were studied. In the karyological analysis, the chromosome number was divided into two groups, one from 27-32, the other was 54-64. The former was presumably the metaphase chromosome number at the meiotic division; the latter was presumably the metaphase chromosome number at the mitotic division. DNA content in the diploid nucleus of the primary oocyte, doubled before the maturation divisions, was reduced through the maturation divisions by one-half in the nuclei of the secondary oocyte and the first polar body and by one-fourth in the nuclei of the egg and the second polar bodies. The first reduction of DNA content corresponded to halving the number of the chromosomes in the first maturation division and the second to the nuclear division in the secondary oocyte. These reductions represent a common process of egg maturation, except the final production of the mature egg with two haploid nuclei, an egg nucleus, and a second polar body nucleus. These two nuclei, which were formed apart in the mature egg, drew near to fuse into a zygote nucleus. The chromosome number and nuclear DNA content were doubled in the zygote and each blastomere in embryos, supporting the hypothesis that the egg nucleus fuses with the second polar body nucleus and this conjugation initiates subsequent embryonic development.

Animals↗

PubMed1992

The amino acid sequence of toxin IV from the Androctonus australis scorpion: differing effects of natural mutations in scorpion alpha-toxins on their antigenic and toxic properties.

The complete amino acid sequence (64 residues) of the AaH IV toxin from the scorpion Androctonus australis Hector was determined by automated Edman degradation and was compared with the sequences of other Androctonus toxins. AaH IV was also tested by radioimmunoassay for binding to antisera raised against other toxins of the same species. The results indicated that AaH IV shares some of the antigenic properties of AaH I and AaH III toxins, but does not cross-react with anti-AaH II antibodies. The structural basis for the observed antigenic relationships can be found in the high degree of homology displayed by AaH IV with regard to AaH I and III, the changes in amino acid residues equally affecting regions included or excluded from the main predicted antigenic sites of AaH IV. The lower biological potency of AaH IV is presumably the result of some of the sequence differences. In particular, substitution affecting the charge and bulkiness of residue 61 could account for the poor receptor binding and consequential weak toxic properties of this molecule.

Amino Acid Sequence↗

PubMed1999