ABSTRACT
Recent recognition about snake bite envenomation on June, 2017 as neglected tropical disease under categoryA by World Health Organization advocated again its undeniable importance. Present circumstances reasoned to work on a neglected subspecies of Naja naja, i.e., Naja naja karachiensis [N. n. karachensis] has been documented for frequent deaths in Pakistan. In this study median lethal toxic dose [LD50] was determined intraperitoneally in Swiss albino mice and was found to be 2.0microg/g [2.0mg/kg] equal in potency to Naja pallida [red spitting African cobra]. Total protein contents [188+/-0.011microg / 200microg of dry weight] were high enough [94%] to represent an arsenal of proteins. Furthermore, 99mTc was labeled 99.9% with venom and didn't find to alter hemolytic activity of venom in dose dependent manner at 125 microg/ml [p<0.5], 250 microg/ml [p<0.1] and 500 microg/ml [p<0.1] when compared with its crude form. Present work will pave the way for proteomics study in effective production of antidote against specific species of snakes as dare demand of it has been felt since long period of time in Pakistan
ABSTRACT
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.