Ultrastructure Development and Some DNA Characteristics of Gomphocerus sibiricus (L) Entomopoxvirus
This paper studied a strain of EPV (Gomphocerus sibiricus entomopoxvirus-GsEPV) isolated from Gomphocerus sibiricus(L) in Mulei county, Xinjiang Autonomous Region in 1992, the EPV may be potentially a kind of bio-pesticide. Using microscopic and biochemical methods to study the ultrastructure, development and characteristics of DNA of this virus, we found that the occlusion body of the virus is spherical, and the maximum diameter is about 6.90μm, the minimum about 3.95μl, the average 5.33μm. With electron microscope, the virion observed is oval, and the size is 267nm×103nm. The core of the virion folds back 2-3 times, and its cross section appears to be round, with 3-4 electronic nondense dots in it. GsEPV mainly infects the fat body of its host. Numbers of EPV occlusion bodies can be observed 15-20 days after inoculation. At this time, there is no free virion, and GsEPV obviously develops quickly and synchronously, so the GsEPV is easy to prevail possibly relating to this character. The GsEPV-DNA, when cleaved with restriction enzymes HindⅢ, BglⅡ and EcoRⅠ, produces 20, 17, 29 DNA fragments, and the molecular weight is 155.37×10 6D, 156.45×10 6D and 156.79×10 6D respectively, and the average is 156.20×10 6D. After comparing with the reported grasshopper EPV, we can classify them into two types: One with spherical occlusion bodies, the other with oval occlusion bodies. The EPV whose occlusion bodies are similar ecah other have the similar core structure and their molecular weight are also similar. In the virion of the EPV with oval occlusion bodies, such as OaEPV, CiEPV, MsEPV, VAcEPV and PnEPV, the DNA chain folds back less (1-2times), and its molecular weight is smaller, often about 125×10 6D; but in the EPV with spherical occlusion bodies, such as DkEPV and GsEPV, the DNA folds back much (2-3times), and its molecular weight is larger, about 155×10 6D.