Effects of venom/calyx fluid from the endoparasitic wasp Cotesia plutellae on the hemocytes of its host Plutella xylostella in vitro.
Crude venom and calyx fluid from Cotesia plutellae (Hymenoptera Braconidae) were assayed for biological activity toward hemocytes of Plutella xylostella (Lepidoptera Plutellidae). Venom from C. plutellae displayed high activity toward the spreading of plasmatocytes of P. xylostella early in the incubation period, and the inhibition was more severe as the concentration of venom increased. However, most inhibited hemocytes spread normally after being incubated for 4h. No effects were found toward granular cells from the host. Additionally, the venom from C. plutellae had some lethal effects on hemocytes of P. xylostella at high concentrations. In contrast, when incubated with different concentrations of calyx fluid, the spreading of some hemocytes was inhibited, some began to disintegrate, and some were badly damaged with only the nucleus left. After 4h, the majority of hemocytes died. The same results were observed when hemocytes were incubated in calyx fluid together with venom. These results show that calyx fluid from C. plutellae may play a major role in the suppression of the host immune system, whereas venom from C. plutellae has a limited effect on hemocytes and probably synergizes the effect of calyx fluid or polydnavirus.
Yu
Rui-xian
RX
Institute of Insect Sciences, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029, China.
Chen
Ya-Feng
YF
Chen
Xue-xin
XX
Huang
Fang
F
Lou
Yong-gen
YG
Liu
Shu-sheng
SS
D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006434:Hemocytes / Q000187:drug effects*; D007814:Larva / Q000469:parasitology; D009036:Moths / Q000166:cytology*; D011679:Pupa / Q000469:parasitology; D014688:Venoms / Q000494:pharmacology*; D014863:Wasps / Q000502:physiology*
D014688:Venoms