Meghan Bialt-DeCelie – ’19

The hints left in the form of fossils provide better understanding of evolution and natural preservation of biological material. The organic material, like proteins, would often be lost and decomposed, hence discovering soft tissue in a fossil is an intriguing find. Researchers led by Dr. Yao-Chang Lee were able to find preserved protein in a 195-million-year-old rib of a sauropodomorph dinosaur from Early Jurassic Dawa, Yunnan Province in China.

This is not the first time proteins were found in fossils, but previous methods of extracting it had higher chances of contamination and flawed or misleading results. In this study, scientists were able to study the presence of proteins in the fossil in situ. They were able to do this with SR-FTIR (synchrotronradiation based Fourier transform infrared) micro-spectroscopy and confocal Raman spectroscopy, which identify molecules like proteins by its vibrational energy from bonds of the compound. A small amount of collagen type 1 was identified in the rib fossil. More specifically, it was located in the vascular canals of the bone. Researchers were able to identify this with the presence of infrared absorption bands for amides A and B, as well as amides I, II, and III, which are all characteristic to collagen. They also found the characteristic left handed triple helix band at 1,637 cm-1.

Along with the collagen, hematite particles were found in the vascular canals of the fossil. Hematite (α-Fe2O3) present themselves as dark-red particles. With the Raman microscopy, researchers were able to identify the hematite with a series of identifying bands of its own. The iron content of hematite suggests it could have derived from hemoglobin or any other iron rich protein from the blood. From the location of the preserved collagen, scientists believe that it once was a component of blood vessels, which also explains the presence of the hemoglobin.

The study stresses the importance of the use of in situ methodologies when identifying organic matter in fossils since it does not introduce as high of a possibility of contamination of biological material from external sources.

References:

1. Lee, Yao-Chang, et al. Evidence of preserved collagen in an Early Jurassic sauropodomorph dinosaur revealed by synchrotron FTIR microspectroscopy. Nature Communications8.14220 (2017). doi:10.1038/ncomms14220.
2. Image retrieved from: https://commons.wikimedia.org/wiki/File:Sternum_and_right_side_of_rib_cage,_seen_from_behind._Waterc_Wellcome_V0007969.jp