Buthus Martensi Karsch Research Articles

Isolation of a purified toxin (Martoxin, MTX) from the venom of the scorpion Buthus martensi Karsch with adrenergic and NANC actions

Isolation of a purified toxin (Martoxin, MTX) from the venom of the scorpion Buthus martensi Karsch with adrenergic and NANC actions

Pharmacological activity of four fractions isolated from the venom of the scorpion Buthus martensi karsch

Pharmacological activity of four fractions isolated from the venom of the scorpion Buthus martensi karsch

Amino Acid Sequence of an Excitatory Insect-selective Toxin (BmK IT) From Venom of the Scorpion Buthus martensi Karsch

The insect-selective neurotoxin(BmK IT) of scorpion Buthus martensi Karsch was first reduced and S-alkylated, and then digested by TPCK-trypsin and Staphylococcus aureus V-8 Protease. The enzymatic peptides were purified on TLC-plastic sheet and submitted to determine their amino acid compositions and sequences. The sequence of the 70 amino acid residues of BmK IT was established with reference to the primary structure of AaH IT, another excitatory insect-selective toxin from the venom of North African scorpion Androctonus australis Hector. About 75% of the homologous sequence was found in the molecules of BmK IT and AaH IT. It is obvious that the results contribute toward better understanding of the molecular structure characteristics, structure/activity relationship of scorpion insect-selective toxins, and they can serve as the molecular basis for utilizing the toxins as a tool to clarify molecular mechanism involved in channel gating, and to infer the possibility of developing them as new selective bioinsecticides.

Lack of effect of a neurotoxin from the scorpion Buthus martensi Karsch on nerve fibers of this scorpion

—A neurotoxin (BmK I) was purified from the venom of the scorpion species Buthus martensi Karsch. Effects of this toxin on the excitability of the abdominal nerve fibers of the same scorpion were examined. The toxin had no effect at all on the action and resting potentials recorded intracellularly even at a concentration as high as 100 μM. A similar result was obtained through optical measurements of the action potential using a potential sensitive dye. Sea anemone toxin II (8 μM) had no effect on nerve excitability either. However, tetrodotoxin (50 nM) reversibly suppressed the action potential and grayanotoxin II (20 μM) induced a sustained depolarization of the nerve membrane which resulted in a reversible suppression of the action potential. BmK I at a concentration of 0.1 μM greatly prolonged the action potential in the crayfish giant axon. We conclude that the Na channel of nerve fibers of this scorpion is totally insensitive to the neurotoxin in this scorpion's venom.

Ionic composition of the haemolymph of a chinese scorpion, buthus martensi

1. 1. Ionic composition of the haemolymph of a Chinese scorpion, Buthus martensi Karsch, was determined. 2. 2. Element analysis showed that the supernatant of ultracentrifuged serum (435,000 g, 30 min) contained (in mM) 291.6 ± 5.8 Na, 6.7 ± 0.8 K, 3.6 ± 0.4 Ca, 0.6 ± 0.07 Mg, and 292.6 ± 6.2 Cl. 3. 3. Ion chromatography showed that the same supernatant contained (in mM) 291 Na and 3.3K. 4. 4. The serum contained other minor components: 2.1Cu, 0.04 Fe, 0.02 Mn, 0.57 Zn (mM), most of which were spun down by the ultracentrifugation. 5. 5. No seasonal variation was observed in the composition. 6. 6. Salines of various ionic compositions showed very little difference in ability to maintain nerve excitability and heart activity. 7. 7. Based on these, we propose a physiological saline for the Chinese scorpion as: 292 Nad, 3.3KC1, 8. 3.6CaCl 2, 0.6MgCl 2, 3Tris-HCl (mM), pH 7.3.

Purification and the partial amino acid sequence of an insect neurotoxin from the venom of scorpion Buthus martensi Karsch

1. 1. A neurotoxic peptide was isolated from the venom of the scorpion Buthus martensi Karsch collected in Henan Province, China. 2. 2. This toxin showed the highest neurotoxic potency to crickets amongst all components in the venom examined. 3. 3. The amino acid composition of the toxin was similar to that of insect toxin 1 of Leiurus quinquestriatus quinquestriatus. 4. 4. The partial primary sequence of the toxin at the N-terminal was very similar to that of an insect toxin of Androctonus australis Hector. 5. 5. We conclude that the neurotoxin we isolated is indeed an insect toxin and thus named it as BmK IT.