Central Facility for Electron Microscopy, University of Ulm, Ulm, Germany.
J Struct Biol. 2009 Dec;168(3):426-36. doi: 10.1016/j.jsb.2009.07.017. Epub 2009 Jul 24.
Composition and spatial distribution of organic and inorganic materials within the cuticle of isopods vary between species. These variations are related to the behaviour and habitat of the animal. The troglobiotic isopod Titanethes albus lives in the complete darkness of caves in the Slovenian Karst. This habitat provides constant temperature and saturated humidity throughout the year and inconsistent food supply. These conditions should have lead to functional adaptations of arthropod cuticles. However, studies on structure and composition of cave arthropod cuticles are rare and lacking for terrestrial isopods. We therefore analysed the tergite cuticle of T. albus using transmission and field-emission electron microscopy, confocal micro-Raman spectroscopic imaging, quantitative X-ray diffractometry, thermogravimetric analysis and atomic absorption spectroscopy. The ultrastructure of the epicuticle suggests a poor resistance against water loss. A weak interconnection between the organic and mineral phase within the endo- and exocuticle, a comparatively thin apical calcite layer, and almost lack of magnesium within the calcite crystal lattice suggest that the mechanical strength of the cuticle is low in the cave isopod. This may possibly be of advantage in maintaining high cuticle flexibility and reducing metabolic expenditures.
陆栖等足目动物外骨骼的有机和无机材料的组成和空间分布在物种间存在差异。这些差异与动物的行为和栖息地有关。穴居等足目动物 Titanethes albus 生活在斯洛文尼亚喀斯特地区洞穴的完全黑暗中。这种栖息地全年提供恒定的温度和饱和湿度以及不稳定的食物供应。这些条件应该导致节肢动物外骨骼的功能适应。然而，洞穴节肢动物外骨骼的结构和组成的研究很少，陆地等足目动物的研究更是缺乏。因此，我们使用透射电子显微镜和场发射电子显微镜、共聚焦微拉曼光谱成像、定量 X 射线衍射、热重分析和原子吸收光谱分析了 T. albus 的背板外骨骼。表皮的超微结构表明其对水分流失的抵抗力差。内、外骨骼中有机相与矿物相的连接较弱，顶端方解石层较薄，方解石晶格中几乎没有镁，这些都表明洞穴等足目动物的外骨骼机械强度较低。这可能有利于保持较高的外骨骼柔韧性和降低代谢支出。
