Purification And Characterization Of An Insecticidal Toxin From The Venom Of Macrothele Raveni

Spider venoms are rich sources of novel toxins, which are of interest as tools for studying neurophysilogy and as potential lead structure for insecticides and Pharmaceuticals. The spider Macrothele raveni was recently identified as a new species of genus Macrothele. It is distributed in the hilly areas of Guangxi, Hunan and Shichuan Province. It has compared the character of the venoms from Macrothele raveni, Haplopelma schmidti, Selenocosmia hainana, Chilobrachy jingzhao.The activity of insecticide, antimicrobial, anti-tumor and all the toxin to the anial were research and compared. One insecticide peptide isolated from the venom of Macrothele raveni was named MR-Eâ…¢.The results of the insecticidal experiment indicated that the venoms from four different spiders including Macrothele raveni, Haplopelma schmidti, Selenocosmia hainana, Chilobrachy jingzhao, all have toxic effect on Helicoverpa armigera and Galler mellonella and demonstrate the obvious poisoning symptom. The venom from Macrothele raveni had the strongest toxic effect by fedding venom on Helicoverpa armigera. The antibacterial experiment showed that the venoms from Macrothele raveni and Haplopelma schmidti were found to have restraining function on Escherichia coli and Staphylococcus aureus and have no effect on Aspergillus flavus sp, Penicillium chrysogenum, Monilia albican and Alternaria solani Sorau. The venoms from Selenocosmia hainana and Chilobrachy jingzhao have no antimicrobial effect. MTT reduction assay was used to determine the tumour cells growth and survival rates with various concentrations of four spider toxins. The results indicated that, for the identical spider toxin with higher concentration does stronger inhibitory effect on growth of tumour cells BGC-823. The spider toxin with the identical concentration responses time longer damps the lump effect to be stronger. Different kinds of spider toxins to BGC-823 function effect differently. The growth of human gastric ademocarcinoma cells BCC-823 was inhibited most significantly by Macrothele raveni in vitro and IC₅₀ is 15.9±0.01μg/mL. The crude venom from Macrothele raveni was found toxic to mice and the LD50 value is 2.83±0.03μg/g body weight.The content of proteins in venom from Macrothele raveni is 78.8%. A new insecticidal toxin named MR-EIII was isolated from the crude venom by reverse phase chromatography (RPC) and cation exchange chromatography. The map of SDS-P AGE of this toxin indicated its molecular weight lOkD less than 14400Da. MR-EIII is toxic to Helicoverpa armigera and the LD50 value of this toxin is 1.18±0.03ug/g.Reverse phase chromatography (RPC) has many advantages such as speediness, high effect etc. The technology of reverse phase chromatography is used in purification of spider venom mostly.