Department of Engineering, Wake Forest University, Winston Salem, NC, 27101, USA.
Museum of Paleontology, University of California, Berkeley, CA, 94720, USA.
Sci Rep. 2019 Oct 30;9(1):15678. doi: 10.1038/s41598-019-51680-1.
The idea that original soft tissue structures and the native structural proteins comprising them can persist across geological time is controversial, in part because rigorous and testable mechanisms that can occur under natural conditions, resulting in such preservation, have not been well defined. Here, we evaluate two non-enzymatic structural protein crosslinking mechanisms, Fenton chemistry and glycation, for their possible contribution to the preservation of blood vessel structures recovered from the cortical bone of a Tyrannosaurus rex (USNM 555000 [formerly, MOR 555]). We demonstrate the endogeneity of the fossil vessel tissues, as well as the presence of type I collagen in the outermost vessel layers, using imaging, diffraction, spectroscopy, and immunohistochemistry. Then, we use data derived from synchrotron FTIR studies of the T. rex vessels to analyse their crosslink character, with comparison against two non-enzymatic Fenton chemistry- and glycation-treated extant chicken samples. We also provide supporting X-ray microprobe analyses of the chemical state of these fossil tissues to support our conclusion that non-enzymatic crosslinking pathways likely contributed to stabilizing, and thus preserving, these T. rex vessels. Finally, we propose that these stabilizing crosslinks could play a crucial role in the preservation of other microvascular tissues in skeletal elements from the Mesozoic.
认为原始软组织结构及其组成的天然结构蛋白可以在地质时间跨度内持续存在的观点存在争议，部分原因是尚未很好地定义在自然条件下可能发生的严格且可测试的机制，从而导致这种保存。在这里，我们评估了两种非酶结构蛋白交联机制，即 Fenton 化学和糖基化，以评估它们对从暴龙（USNM 555000[以前称为 MOR 555]皮质骨中回收的血管结构保存的可能贡献。我们使用成像、衍射、光谱和免疫组织化学证明了化石血管组织的内源性，以及最外层血管层中存在 I 型胶原蛋白。然后，我们使用源自暴龙血管同步辐射 FTIR 研究的数据来分析它们的交联特性，并与两种非酶 Fenton 化学和糖基化处理的现生鸡样本进行比较。我们还提供了对这些化石组织化学状态的 X 射线微探针分析，以支持我们的结论，即非酶交联途径可能有助于稳定，从而保存这些暴龙血管。最后，我们提出这些稳定的交联可能在保存中生代骨骼元素中的其他微血管组织中发挥关键作用。
