Program in Biomedical Science and Engineering, Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea.
Department of Ocean Sciences, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea.
Sci Rep. 2022 Jul 12;12(1):11816. doi: 10.1038/s41598-022-15982-1.
Animals living in extreme environments, such as hydrothermal vents, would be expected to have evolved protective shells or exoskeletons to maintain homeostasis. The outer part of the exoskeleton of vent crabs (Austinograea sp.) in the Indian Ocean hydrothermal vent was one of the hardest (approximately 7 GPa) biological materials ever reported. To explore the exoskeletal characteristics of vent crabs which enable them to adapt to severe environments, a comparative analysis was conducted with the Asian paddle crab (Charybdis japonica) living in coastal areas. Nanoindentation, thermogravimetric analysis, scanning electron microscopy, energy dispersive x-ray analysis, and Raman spectroscopy were used to analyze the mechanical properties, thermal stability, structure, surface components, and the composition of compounds, respectively. Though both species have four-layered exoskeletons, the outermost layer of the vent crab, a nano-granular structure, was much thicker than that of the coastal crab. The proportions of aluminum and sulfur that constitute the epicuticle of the exoskeleton were higher in the vent crab than in the coastal crab. There was a lack of water or volatile substances, lots of CaCO, and no carotenoid-based compounds in the exoskeleton of the vent crab. These might have improved the mechanical properties and thermal stability of the hydrothermal species.
生活在极端环境中的动物，如热液喷口，预计会进化出保护性的外壳或外骨骼来维持体内平衡。印度洋热液喷口的管足蟹（Austinograea sp.）的外骨骼外层是迄今为止报道的最坚硬的生物材料之一（约 7 GPa）。为了探究使管足蟹适应恶劣环境的外骨骼特征，对生活在沿海地区的亚洲招潮蟹（Charybdis japonica）进行了比较分析。采用纳米压痕、热重分析、扫描电子显微镜、能谱分析和拉曼光谱分别分析了机械性能、热稳定性、结构、表面成分和化合物组成。尽管这两个物种都有四层外骨骼，但热液喷口蟹的最外层是纳米颗粒结构，比沿海蟹的外骨骼要厚得多。热液喷口蟹外骨骼的表皮中铝和硫的比例高于沿海蟹。热液喷口蟹的外骨骼中缺乏水或挥发性物质、大量的 CaCO 和不含类胡萝卜素的化合物。这些可能提高了热液物种的机械性能和热稳定性。
