Hornet silk caps maintain a clean room environment: a device for filtering out bacteria and dust particles

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• 作者：Shabtai ; Yossef ; Ishay ; Jacob S.
• 关键词：Hornet ; Vespa orientalis ; Hornet combs ; Hornet larvae ; Silk caps ; Filtration ; Gas filtration ; Clean room ; Semi-conductive device
• 刊名：Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology
• 出版年：1998
• 出版时间：July, 1998
• 年：1998
• 卷：120
• 期：3
• 页码：565-570
• 全文大小：549 K

文摘

The ultrafiltrational properties of the silk caps of the hornet Vespa orientalis (Hymenoptera, Vespinae) were studied. Pupating hornet larvae produce a silk cocoon whose cap is made up of cross-linked silk fibers with sporadic flat plates that partially fill the gaps between the fibers. Large free gaps of up to 100 μm exist between the silk fibers, but the cocoon and its cap is a multilayered structure with at least ten fiber layers, thereby preventing E. coli K12 sp. bacteria or tiny particles of titanium dioxide (TiO₂) with a size range of 1-30 μm from passing through the silk caps during wet centrifugal filtration or dry gas filtration performed at 2 bar. Of 10⁷ bacteria or TiO₂ particles per ml loaded on the upstream side of the filtering silk cap, less than 100 particles per ml were counted in the liquid filtrate collected following wet centrifugal filtration and even fewer number of particles were detected in the filtered air during forced gas filtration through the silk caps. These findings suggest that the pupal silk caps function as an efficient filtration system affording the developing pupa the appropriate physical and biological conditions for the production of its cuticle during pupation. Such ‘clean room’ conditions are a sine qua non during the formation of the semi-conductive elements that characterize the adult hornet cuticle.