Induced pathophysiological alterations by the venoms of the most dangerous Moroccan scorpions Androctonus mauretanicus and Buthus occitanus: A comparative pathophysiological and toxic-symptoms study.

Scorpion envenomation is a serious public health issue. Androctonus mauretanicus (Am) and Buthus occitanus (Bo) are the most dangerous scorpions in Morocco. Despite their medical relevance, no study has yet related their kinetics of symptom apparition and the consequent tissue disorders at the same interval post-injection. This work achieved the first comparative pathophysiological and toxic-symptoms study between the Am and Bo venoms from a biochemical, toxicological and physiopathological standpoint. The activity of venoms and their subletal dose were determined by administration of increasing concentrations of the venoms. 30, 60 and 120 min following the experimental envenomation in mice, the profile of clinical symptoms was underlined and the main organs: brain, heart, lungs, liver and kidneys were removed for histological examination. The Am venom is a rich source of proteins and three-times more toxic than the Bo. The most observed clinical symptoms are neurological and cardiopulmonary. The Am venom caused histopathological alterations at 30, 60, and 120 min which were more important than the Bo. This study highlighted that both venoms exhibited a strong toxicity with variable intensities. Moreover, we showed the presence of correlation between the level of histopathological disorders observed and the intensity of signs appeared at the same time following venom inoculation.

Characterization of Am IT, an anti-insect β-toxin isolated from the venom of scorpion Androctonus mauretanicus / 生理学报

In the present study, a 'novel' toxin, called Am IT from the venom of scorpion Androctonus mauretanicus is isolated and characterized. A detailed analysis of the action of Am IT on insect axonal sodium currents is reported. Am IT was purified through gel filtration followed by C18 reversed-phase HPLC. Toxicity of Am IT in vivo was assessed on male German cockroach (Blattella germanica) larvae and C57/BL6 mice. Cross-reactivity of Am IT with two β-toxins was evidenced using (125)I-iodinated toxin-based radioimmunoassays with synaptosomal preparations from rat brain. The complete amino acid sequence of Am IT was finally determined by Edman sequencing. Am IT was observed to compete with AaH IT4 purified from the venom of scorpion Androctonus australis in binding assays. It was recognized by an antibody raised against a β-type toxin, which indicated some structural similarity with β-toxins (or related toxin family). The 'novel' toxin exhibited dual activity since it competed with anti-mammal toxins in binding assays as well as showed contracting activity to insect. The toxin competed with radio-labeled β-toxin Css IV by binding to Na(+) channels of rat brain synaptosomes. Analysis of toxin amino acid sequences showed that Am IT shares high structural identity (92%) with AaH IT4. In conclusion, Am IT not only reveals an anti-insect compound properties secreted by 'Old World' scorpions, paralyzing insect larvae by binding to Na(+) channels on larvae's nerve-cell membranes, but also exerts toxic activity in mice, which is similar to anti-mammal toxins from 'New World' scorpions (North and South Americas). Therefore, Am IT appears to be structurally and functionally similar to AaH IT4.