Two new arthropod toxins purified from the venom of the Mexican scorpion Centruroides nigrescens

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  Two new arthropod toxins purified from the venom of the Mexican scorpion Centruroides nigrescens Abstract The venom of the slender black scorpion Centruroides nigrescens , from the State of Guerrero México, was fractionated by Sephadex G–50 gel filtration, followed by carboxymethyl cellulose ion separation and high–performance liquid chromatography, permitting to obtain two new peptides toxic to arthropods. The estimate LD 50 of the soluble venom for the insect Acheta domesticus was 11.1 μg/g body weight, and for the arthropod Armadillidium vulgare was 61.1 μg body weight . The amino acid sequence of toxin Cnige1 (toxic to A. domesticus and A. vulgare ) contains 65 amino acids, with a molecular mass of 7273.37 mass units, whereas toxin Cnige2, toxic to A. domesticus , contains 68 amino acids, with a molecular mass of 7548.81 units. Both peptides are well packed, containing 8 cysteines, which in the native venoms are forming 4 disulfide bridges each. The amino acid sequences f...

External morphology of Hemiscorpius lepturus Peters, 1861 (Scorpiones: Hemiscorpiidae)

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External morphology of Hemiscorpius lepturus Peters, 1861 (Scorpiones: Hemiscorpiidae)

Abstract


Hemiscorpius lepturus Peters, 1861 is redefined in both sexes. The detailed external morphologies of chelae, pectinal organs, chelicerae, telsons, and legs I-IV were surveyed with the scanning electron microscope (SEM) in both sexes of H. lep-turus for the first time. The constellation arrays, bat-like shaped peg sensilla, trichobothria, and the other sensillar and epicuticular structures were described, and their functional morphologies were interpreted considering the species' habitat and other climatic preferences. The constellation arrays, basiconic sensilla, function as a chemoreceptor (hygro-reception or/and thermo-reception) by its location on the pedipalp in the habitat. The shape of the peg sensilla is remarkably bat-like in both sexes and this shape has not been observed or recorded in any scorpion species, functioning as mechanoreception and contact chemo-reception. There are three slit sensilla as single slit, dual and triple slit sensilla on I-IV walking legs, being mechanoreceptors as proprioceptors detecting strain and substrate vibrations during movement. Isolated single slit sensillum was recorded on the chelicerae surface of a scorpion species for the first time.