Molecular biological analysis of the Babesia parasite transmission blocking mechanism conducted by tick aminopeptidase.

壁虱是莱姆病等人畜共患传染病的生物媒介，但其在病原体传播中的分子功能尚不清楚。硬蜱中肠宿主血液消化的一种末端酶是一种氨基肽酶HlLAP，它被证明通过抑制其侵袭而参与了对硬蜱迁移的调节作用。在细胞生物学研究的基础上，我们观察到RNA干扰沉默HlLAP基因诱导了中肠未成熟的周围膜的产生。PM是中肠上皮对宿主血餐中细菌或异物的机械屏障。因此，推测导致PM产生的HlLAP对PM的干扰间接抑制了巴贝斯虫对中肠上皮的入侵。

Tick is well known biological vector of zoonotic infectious diseases such as Lyme disease but the tick molecular function regarding pathogen transmission is poorly understood. A terminal enzyme of host blood digestion in tick midgut was an aminopeptidase, HlLAP which was shown to be involved in the regulatory effect on babesial migration in tick by inhibiting its invasion. Based on the cellular biological study, we observed that HlLAP gene silencing by RNA interference induced the immature generation of peritrophic membrane (PM) in midgut. PM is the mechanical barrier of midgut epithelium against bacterial or xenobiotic substances in host blood meal. Therefore, it was assumed that HlLAP which was responsible for the generation of PM disruption of which inhibited indirectly an invasion of Babesia parasite into the midgut epithelium.