Venom Apparatus And Component And Partial Physiological Function Of Chouioia Cunea Yang’s Venom

As an important international quarantine pest, Hyphantria cunea was endangered a variety of trees and crops, and affected our agricultural and forestry production and ecological environment seriously. Chouioia cunea Yang is an important pupa porositoids of H, cunea. C. cunea is widely used in the H. cunea and has a remarkable effect because that C. cunea has a highly parasitic rate, easy-to-bred and the prevention effect was lasting. The resent researches of C. cunea were focus on morphology and the technique of artificial breeding and releasing. While the interactions between the parasitoids and host and the parasitic mechanism was not reported. The C. cunea was studied to clarify the production, function and composition of its venom. The ultrastructure of the venom apparatus and the effect of C. cunea parasitize on the carbohydrate metabolize of host were studied, the effect of parasitoid venom on the heamocytes of host’s cellular defense was determined as well, and the components of venom proteins was analyzed finally. The results were as follows:1. The ultrastructure of the venom apparatus:The ultrastructure of the venom apparatus of C. cunea were studied by ultrathin sectioning technique and electron transmission microscope. The results showed that the venom apparatus of C. cunea consisted of a venom reservoir and a venom gland. Numerous secretory cells which contained many organelles, such as nucleus, secretory vesicles, mitochondria, autophagic vacuoles, end apparatus and microvilli, were found in the venom gland. It’s showed that the venom gland has strong secretory function rather than storage function. The venom reservoir consisted of three layers as muscular sheath, epithelial cell layer and intima layer. The muscle fibers in the muscular sheath were finely organized and uncross. There were a few of organelles in the epithelial cell. The intima was thickened wavy. The venom reservoir can store venom only, and the venom was discharged by the muscle contraction of venom reservoir.2. The effect of parasitoid on the carbohydrate metabolize of H, cunea:the glycogen and trehalose content in host pupa hemolymph were tested by the anthrone colorimetry, and the content of reducing sugar and the activity of trehalase were tested by the 3,5-dinitrosalicylic acid colorimetry. The results showed:the glycogen content of parasitized host was higher than that of unparasitized host. While the reducing sugar content of parasitized host was similar with that of unparasitized host. The trehalose content of parasitized host was higher than unparasitized host when parasitized 5-8d. These carbohydrate metricales can mutual transformation and provided the energy substances to the growth of the progeny of parasitoid wasp. The trehalase activity of parasitized host was basically same as that of the unparasitized host in the first 6 days, therefore, it was increased significantly when parasitized 7-14d. The variety of trehalase activity was correlated with the variety of carbohydrate content.3. The effect of parasitoid venom on the heamocytes of host’s cellular defense:plasmatocytes were sperated by Na2-EDTA treatment; meanwhile, gramulares were seperated by nylon wool method. We used the cell cultured in vitro, to study the effects of parasitoid venom on the encapsulation and phagocytosis. The results shows:the encapsulation of plasmatocytes was stronger than that of gramulares. The encapsulation capacity of hesmocytes were significantly inhibited by the parasitoid venom, the encapsulation capacity were deceased with the increase of venom concentration. The encapsulation increased at the beginning and then decreased gradually. Encapsulation of plasmatocytes reached to the maximum at 12h. The encapsulation increased at the beginning and then decreased gradually. Encapsulation of plasmatocytes reached to the maximum at 12 h. In the control, encapsulation of gramulares was the strongest at 15 h. But encapsulation of gramulares was the strongest at 12h when treated by parasitoid venom (concentration 0.01-0.03 VRE), while it was the strongest at 9 h when treated by the venom (concentration 0.04-0.10 VRE). The phagocytosis of plasmatocytes was stronger than that of gramulares. The phagocytosis capacity of hesmocytes were significantly inhibited by the parasitoid venom, however the inhibition of parasitoid venom on gramulares were not as strong as that on plasmatocytes.4. The components of venom proteins:the venom protein average of one venom reservoir was tested by the Bradford method, and it was about 2.75μg and changed with the development of the wasp and the size of the venom reservoir. It was found that molecular weight of most venom proteins were between 14.4-116kDa by SDS-PAGE. Most of the proteins were acidic protein. Finally, there were 177 proteins were detected in the wasp’s venom by the electrospray ionization mass spectrometry (ESI-MS), such as calreticulin, serine protease inhibitors, phenol oxidase, serine and enkephalin. But the trehalase which was a common protein in venom of other parasitoid wasps was not found in C. cunea, while the uncommon kinase was discovered in venom of this wasp.