Preliminary Study Of Molecular Basis Of Sex-differentiation On Ovomermis Sinensis

Ovomermis sinensis Chen et al., 1991 is one of insect-parasitic nematode. Many insect species are susceptible to this nematode, for example, Leucania separata, Heliothis armigera, Prodenia litura, Spodoptera exigua, Plutella xylostella, Pieris rapae, Agrotis ypsilon, Euxoa segetum etc. This insect host invariably dies when the juvenile nematode completes its parasite development and exits from the host's hemocoel (the parasite's microenvironment). The nematode can't infect man and domestic animals, so it has potential for the biological control of a range of insect pests. From the nematode has been named, the study of its sex-differentiation has only rested on microscopically level. The former experiments only approved its sex-differentiation is related to circumstance factors. We haven't found the study on the molecular basis of sex-differentiation on Ovomermis sinensis.At first, we find the sex-differentiation of Ovomermis sinensis suffers the environment influence. In order to investigate this mechanism, the author adopted molecular methods to find the difference of the nematode's male and female imago.We first use Random Amplified Polymorphic DNA (RAPD) method to analyze genome DNA of the nematode's male and female imago. We have got some clear and well-repeated bands. It shows that the gene of male and female imago is approximately similar, but it exists the specific difference.We have analyzed the dissoluble protein difference between male and female imago through electrophoresis. The results of SDS-page indicates: more than three kind of protein can be specially expressed in female imago, whose molecular weight are in the region of 15-16KD, 21-24KD and 72-76KD respectively. On the contrary, there is only one special protein with the molecular weight of 26KD in the male imago. Further research reveals in the 2-DE proteins can be well separated, and it can give rise to clear atlas and plenty of differentia proteins.In order to make sure which is sex-differentiation related gene, we have carried out mRNA RT-PCR both in male and female imago. We have attainedapproximately 170 bands dispersed in 100~2500bp. Moreover, the explanation of different dimmers combination results in different species and the numbers of the bands. This depicts that there is some gene expressed differently between male and female imago. This is the right factor that has intimate relation to sex-differentiation. The whole procedure initiates a novelty technique in the study of Mermithidae. What's more, it has settled a rigid foundation for the further research.