Phenoloxidase plays an important role in d efense mechanisms in insect immunity. The complemental deoxyribonuc leic acid （cDNA） of Bombyx mandarina prophenoloxidase (PPO) gen e was cloned by means of reverse transcription polymerase chain reaction （RT-P CR） and rapid amplification of cDNA ends (RACE). The cDNA was 2 134 bp in l ength a nd contained an open reading frame (ORF) of 2 082 bp which encoded 693 amino aci d residues．The deduced amino acid sequence showed a high identity to the report ed sequence of PPO2 from other Lepidopterous insects and shared the typical stru ctural features of PPO from other insects. The results of RT-PCR showed that PP O mRNA was expressed in the integument, haemocyte, head, testis, ovary, fat body and midgut of 5th instar larvae and at different developmental stages of B. m andarina. These results provide molecular basis for further studying the funct ion of ppo gene inB. mandarina.

In order to determine the apoptotic inductivity of botani cal components toSpodoptera litura cultured cell line SL-1, th e concentration and time dependence of apoptotic-induce ability of nine botanic a l components, including azadirachtin and comptothecin, to SL-1 was investigated by inverted phase contrast microscope. The results showed that a great deal of a poptotic bodies appeared, one of the typical morphological characteristics of ap optosis, 24-48 h after treatments with azadirachtin at a concentration of 0.1-5.0 μg/mL and comptothecin at 0.5-20.0 μmol/L; the same changes, however, di d not appear in SL-1 cells within the whole observation period of 72 h after tre atments with tea saponin, ricinine, sassafras, paeonolum, nicotine, matrine and macleay cordata at concentrations of 0.5-20 μg/mL. Treated by azadirachtin at a concentration of 0.75 μg/mL, the early, mid and late apoptotic stages apoptosis of SL-1 cells appeared during0-36 h, 36-60 h and 60 h af ter treatment, respectively; and treated by comptochetin at a concentration of 5.0 μmol/L, these appeared during 0-24 h, 24-52 h and 54 h after treament, re spectively. It is tentatively concluded that azadirachtin and camptothecin both possess the concentration\|time-dependence induction of apoptosis to SL-1 cel ls.

Sericinus montelus Gray is an ornamental insect with exploitability, which overw inters as diapause pupae, and adults have polymorphism. In this study, the morph ology of diapause and non-diapause pupae and their adults were inve stigated in this butterfly in terms of color, body and wing size, and the length of spine on the 9th abdomen of pupae. Compared with non-diapause pupae, the co l or of diapuase pupae is darker. The faint yellow of antenna terminal is obviousl y different from the body color. The length of spine on the 9th abdomen of 3-day-old diapause pupae is about four times that of 3-day-old non-diapau se pupae. Therefore, non-diapause and diapause pupae can be identified at this s tage. The wingspan and tail length of adults from diapause pupae are significant smaller than those of adults from non-diapause pupae. There are also obvious differences in pattern of abdomen and wing. These differences are consistent wit h the descriptions of the spring form and summer form in this butterfly. The res ults suggest that the seasonal polymorphism of adult is related to diapause in S. montelus.