Spatial distribution of orally administered viral fusolin protein in the insect midgut and possible synergism between fusolin and digestive proteases to disrupt the midgut peritrophic matrix
Spatial distribution of orally administered viral fusolin protein in the insect midgut and possible synergism between fusolin and digestive proteases to disrupt the midgut peritrophic matrix
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DOI：
10.1007/s00705-018-4013-5
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发表时间：
2018-09
影响因子：
2.7
通讯作者：
W. Mitsuhashi;Sachiko Shimura;K. Miyamoto;Takafumi N. Sugimoto
中科院分区：
文献类型：
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作者：
W. Mitsuhashi;Sachiko Shimura;K. Miyamoto;Takafumi N. Sugimoto
昆虫痘病毒纺锤体（fusolin蛋白质的微观结构）的口服接种导致昆虫中肠中的围食基质（peritrophic matrix，PM）破坏，所述PM是抵抗微生物感染的物理屏障。虽然已经确定了fusolin的原子结构，但很少直接阐明PM的破坏机制。在本研究中，我们首先进行了免疫组织化学检查，以确定是否fusolin的PM直接或间接的行为在中肠的家蚕，接种纺锤体的Anomala cuprea昆虫痘病毒。这表明，PM，而不是中肠细胞，是fusolin的附着位点。Fusolin广泛地附着在PM的前部到后部区域，既附着在PM的外围食表面和内围食表面，也附着在PM内。这些结果可能解释了为什么整个PM迅速分解。第二，我们给予蛋白酶抑制剂与纺锤体混合，并观察到中肠蛋白酶活性降低和PM破坏减少。这表明中肠蛋白酶也积极参与PM破坏。基于目前的研究结果，我们提出了一个整体的机制，通过管理fusolin的PM中断。
Oral inoculation of entomopoxvirus spindles, microstructures composed of fusolin protein, causes disruption of the peritrophic matrix (PM), a physical barrier against microbe infection, in the insect midgut. Although the atomic structure of fusolin has been determined, little has been directly elucidated of the mechanism of disruption of the PM. In the present study, we first performed an immunohistochemical examination to determine whether fusolin acts on the PM directly or indirectly in the midgut ofBombyx morilarvae that were inoculated with spindles of Anomala cuprea entomopoxvirus. This revealed that the PM, rather than the midgut cells, was the attachment site for fusolin. Fusolin broadly attached to the PM from the anterior to the posterior region, both to its ectoperitrophic and endoperitrophic surfaces and within the PM. These results likely explain why the whole of the PM is rapidly disintegrated. Second, we administered protease inhibitors mixed with spindles and observed decreased midgut protease activity and reduced disruption of the PM. This suggests that midgut protease(s) is also positively involved in PM disruption. Based on the present results, we propose an overall mechanism for the disruption of the PM by administration of fusolin.