The Study On The Biochemical Components In Haemolymph Of Heliothis Armigera Infected By Ovomermis Sinensis

The insect parasitic nematode, Ovomermis sinensis has the potential for the biological control of a range of insect pests due to 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. The insect host invariably dies when the juvenile nematode completes its parasitic development and exits from the host's hemocoele. There is an important significance for studying the biochemical component in the haemolymph of its host, H. armigera so as to offer the indispensable biochemical parameter to succeed in confecting the culture medium. The effects on the level of free amino acids, free fatty acids, trehalose and reducing sugar in the haemolymph of H. armigera infected by O. cinensis were studied. The main results are as follows:After H. armigera was infected by O. cinensis for one day, the total of free amino acids in the haemolymph of its host decreased greatly. Compared with the control experiment, the total of free amino acids in the host's haemolymph had not too changes during 2-4 days, the level of some free amino acids increased and the others decreased. The total of free amino acids and all kinds of free amino acids in the host's haemolymph during 5-6 days increased rapidly. The results showed that the change of level of free amino acids in the host's haemolymph benefited the growth of 0. cinensis. During the first three days of infection, the level of reducing sugar in the haemolymph of H. armigera was lower than that of the control group. But After four days of infection, it became higher than that of the control group. As for the trehalose, the situation was not the same as the reducing sugar. During the first three days of infection, the level of trehalose was almost the same as that of the control group. After four days of infection, it became higher than that of the control group. The relative levels of other free fatty acids were much lower and varied completely. The relative levels (%) of unsaturated fatty acids in the infected anduninfected H. armigera were all 80% or so, and the unsaturated index was from 1.67 to 6.27.During the first three days of infection, the levels of unsaturated fatty acids in the haemolymph of//, armigera of the infection declined little by little. But for the saturated fatty acids, it was on the contrary. After four days of infection, the level of unsaturated fatty acids rose little by little, and the saturated fatty acids were again on the contrary. The variety of free fatty acids in the haemolymph of the infected and uninfected H. armigera was analyzed with gas chromatography. The relative levels of Palmitic acid, Palmitoleic acid, Satiric acid, Oleic acid, Linoleum acid and Lanoline acid etc in the haemolymph were much higher than that of other fatty acids, compared with the control group.The best growth obtained among the best media is TC-199 supplemented with 20% heat inactivated fetal bovine serum (Wang Guoxiu, 2001), and the result is similar to that of O. cinensis' growth in vivo in the last days. According to primary research on the free amino acids, free fatty acids, trehalose and reducing sugar in haemolymph of H. armigera infected by O. cinensis, during the middle and last of O. cinensis in vitro, we should gradually replace the medium with higher free amino acids and reducing sugar content so as to succeed in the in vitro culture of O. sinensis. At the same time, according to the O. cinensis' different growth stage, the free fatty acids' comparison and content of the culture medium should be adjusted on time. The research results will guide the in vitro culture of O. sinensis.