Porter Marianne E, Koob Thomas J, Summers Adam P
Comparative and Evolutionary Physiology, Department of Ecology and Evolutionary Biology, 321 Steinhaus Hall, University of California, Irvine, CA 92697-2525, USA.
J Exp Biol. 2007 Oct;210(Pt 19):3319-27. doi: 10.1242/jeb.006189.
Elasmobranch vertebral cartilage has a substantial mineral fraction (39-55%) and the arrangement of mineral varies among species. We examined vertebrae from one shark species, Mustelus californicus, to determine mineral content, the effect of mineral on material properties and the viscoelastic response of vertebral cartilage. We serially demineralized vertebrae and compressively tested them to failure at varying strain rates. Mineral in vertebral cartilage varies within individuals, intraspecifically and interspecifically; this is in contrast to bone, in which significant variation in mineral content is pathological or an interspecific effect. Within Mustelus, vertebrae with larger mineral fractions were significantly stiffer and stronger; however when variation is assessed across species, the structure has a larger effect. Shark vertebral cartilage did not show a substantial viscoelastic response at biologically relevant strain rates, validating the use of quasistatic testing for this material.
软骨鱼类的脊椎软骨含有大量矿物质成分（39%-55%），且矿物质的排列因物种而异。我们研究了一种鲨鱼——加州星鲨（Mustelus californicus）的脊椎，以确定矿物质含量、矿物质对材料特性的影响以及脊椎软骨的粘弹性反应。我们对脊椎进行连续脱矿处理，并在不同应变率下对其进行压缩测试直至破坏。脊椎软骨中的矿物质在个体内、种内和种间均存在差异；这与骨骼不同，骨骼中矿物质含量的显著变化是病理性的或种间效应。在加州星鲨中，矿物质含量较高的脊椎明显更硬更强；然而，当跨物种评估差异时，结构的影响更大。鲨鱼脊椎软骨在生物学相关应变率下未表现出显著的粘弹性反应，这验证了对该材料进行准静态测试的可行性。
