“巨骨舌魚”（亞馬遜流域一種淡水魚）的魚鱗內(nèi)的盤狀結(jié)構(gòu)的排列,，是其能夠保護自己不被“水虎魚（食人魚）”咬傷的關(guān)鍵。這一發(fā)現(xiàn)發(fā)表在本期Nature Communications上,。
人們知道，“水虎魚（食人魚）”是可怕的攻擊者,，它們的利齒能夾住獵物,，使其喪失能力。某些魚類進化出了能夠避免這種攻擊造成死亡的能力：有些形成了能夠更快游動的能力,，而其他的則長出了堅硬的自然盔甲（以保護性魚鱗形式存在）,，后者能吸收咬噬牙齒的撞擊力。Robert Ritchie和他的研究小組發(fā)現(xiàn),，“巨骨舌魚”魚鱗中名為“薄片”（lamellae）的盤狀結(jié)構(gòu)的分布使這種魚能吸收來自一個所施加負荷的能量,。他們發(fā)現(xiàn)，這種魚是通過改變“水虎魚”牙齒所施加高壓力的方向,、扭轉(zhuǎn)這種壓力,、并有可能減輕這種壓力以及防止自己的鱗片被壓碎來做到這一點的。作者得出的結(jié)論是,，外層“薄片”使魚鱗具有硬度和抗穿透力,，而魚鱗和“薄片”的波紋狀外表面的重疊則使魚鱗能夠以這種方式彎曲，將拉張應(yīng)力轉(zhuǎn)移給內(nèi)層的,、下層的魚鱗,。（生物谷Bioon.com）
生物谷推薦的英文摘要
Nature Communications doi:10.1038/ncomms3634
Mechanical adaptability of the Bouligand-type structure in natural dermal armour
Elizabeth A. Zimmermann，Bernd Gludovatz,，Eric Schaible,，Neil K. N. Dave，Wen Yang,，Marc A. Meyers& Robert O. Ritchie
Arapaima gigas， a fresh water fish found in the Amazon Basin,， resist predation by piranhas through the strength and toughness of their scales,， which act as natural dermal armour. Arapaima scales consist of a hard， mineralized outer shell surrounding a more ductile core. This core region is composed of aligned mineralized collagen fibrils arranged in distinct lamellae. Here we show how the Bouligand-type (twisted plywood) arrangement of collagen fibril lamellae has a key role in developing their unique protective properties,， by using in situ synchrotron small-angle X-ray scattering during mechanical tensile tests to observe deformation mechanisms in the fibrils. Specifically,， the Bouligand-type structure allows the lamellae to reorient in response to the loading environment； remarkably， most lamellae reorient towards the tensile axis and deform in tension through stretching/sliding mechanisms,， whereas other lamellae sympathetically rotate away from the tensile axis and compress,， thereby enhancing the scale’s ductility and toughness to prevent fracture.
