大劣按蚊血淋巴酚氧化酶与约氏疟原虫卵囊黑化关系的研究

目的：探讨大劣按蚊血淋巴酚氧化酶（PO）与约氏疟原虫卵囊黑化的关系。方法：以大劣按蚊/约氏疟原虫模型，利用聚丙酰凝胶电泳后的酶底物显色法，比较、分析血餐后5、7、11、15d时不吸血组、吸正常血组和感染组3组的雌大劣按蚊血淋巴酚氧化酶的单酚氧化酶（MPO）和双酚氧化酶（o-DPO)活性；同时观察感染组约氏疟原虫的感染度及其卵囊黑化比率。结果：感染组的血淋巴MPO和o-DPO酶活性明显高于不吸血组和吸正常血组（P＜0.05)；但是随着约氏疟原虫卵囊黑化比率的增高，感染组血淋巴MPO和o-DPO活性逐渐下降。另外，吸正常血组的MPO和o-DPO酶活性明显高于不吸血组（P＜0.05)。结论：吸血和约氏疟原虫的感染均能激活大劣按蚊前酚氧化酶级联反应，而大劣按蚊血淋巴酚氧化酶可能在大劣按蚊对黑化约氏疟原虫卵囊中发挥重要作用。

Relationship between hemolymph phenol oxidase and melanization of Plasmodium yoelii oocysts in Anopheles dirus

Objective To explore the relationship between hemolymph phenol oxidase and the melanization of Plasmodium yoelii oocysts in Anopheles dirus. Methods An Anopheles dirus-Plasmodium yoelii system was used Anopheles dirus were divided into 3 groups, that is, non-blood-fedding (N), normal-blood-fedding (B) and infected-blood-fedding (I). The activities of MPO and o-DPO in hemolymph from 3 groups were determined with native polyacrylamide gel electrophoresis (PAGE) and density scanning at 5, 7, 11 and 15 d after blood feeding. Results Both MPO and o-DPO activity were significantly higher in group I than group N and B (P<0.05). But with the melanization of Plasmodium yoelii oocysts, both MPO and o-DPO activity in group I were decreased in comparison with group N, especially on the 15 th day after infected-blood feeding. MPO and o-DPO activity in group B were significantly stronger than those of group N. Conclusion Blood feeding and infection of Plasmodium yoelii both can activate the cascade. The heamolymph phenol oxidase may play an important role in the melanization of Plasmodium yoelii oocysts in Anopheles dirus.