大蠟蛾幼蟲血液對綠殭菌感染寄主之抑制作用

以綠殭菌(Nomuraea rileyi)與白殭菌(Beauveria bassiana)的分生孢子(conidia)黏附昆蟲體表方式可感染斜紋夜蛾(Spodoptera litura)五齡幼蟲，而大蠟蛾(Galleria mellonella)幼蟲可受白殭菌的感染但不受綠殭菌的感染；另以注射綠殭菌與白殭菌的菌絲體(hyphal body)方式也得到相同結果。抽取大蠟蛾幼蟲的血液經去除血球後，可抑制綠殭菌菌絲體在PDB+Y固體培養基的生長，產生的菌落數與對照組相比降至僅43%；但將血液先分別以蛋白質分解酵素(proteinase K)或95℃加熱5min處理，則產生的菌落數與對照組相比仍各維持在67及95%。若以斜紋夜蛾幼蟲的血液，無論是否予以不同處理，產生的綠殭菌菌落數皆與對照組相當。由以上結果顯示大蠟蛾幼蟲不受綠殭菌感染，乃因其血液中之體液性因子可抑制其菌絲體的生長，而斜紋夜蛾幼蟲受感染，則由於其血液中不含此因子，以抑制菌絲體生長之故。因此，大蠟蛾血液內含有疑似蛋白質成分，能抑制其受綠殭菌之感染。

關鍵字

蟲生真菌；綠殭菌；大蠟蛾；斜紋夜蛾；血液

並列摘要

The 5(superscript th) instar larvae of Spodoptera litura can be infected with both Nomuraea rileyi and Beauveria bassiana through cuticular contact inoculation with conidia, whereas those of Galleria mellonella can only be infected with B. bassiana but not with N. rileyi. Similarly, the fungal infection in both insect species was obtained through inoculation by injecting their hyphal bodies into a hemocoel. When the N. rileyi hyphal bodies were treated with the hemolymph of G. mellonella without hemocyte, the number of colonies on solid PDB+Y medium formed from the treated hyphal bodies was greatly reduced to approx. 43% compared with that of the control group grown in medium only. However, when the hemolymph was pre-treated with proteinase K or 95℃ for 5 min, the number of colonies remained at 67 or 95%, respectively. When assayed with the hemolymph of S. litura without hemocyte, the number of N. rileyi colonies remained the same as the control group, indicating that S. litura hemolymph does not contain a humoral factor against this fungus. Therefore, the hemolymph of G. mellonella contains humoral factor s), which seems to be proteinaceous based on its inactivation by proteinase and heat, to suppress infection of G. mellonella with N. rileyi.

並列關鍵字

entomopathogenic fungus ； Nomuraea rileyi ； Galleria mellonella ； Spodoptera litura ； hemolymph

國際替代計量

大蠟蛾幼蟲血液對綠殭菌感染寄主之抑制作用

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