A toast to the proteins in dinosaur bones

A burnt toast and dinosaur bones have a common trait.

Dinosaur blood vessel with adjacent bone matrix that still contains bone cells. These structures have a perfect morphological preservation over hundreds of millions of years, but are chemically transformed through oxidative crosslinking. The extract comes from a sauropod dinosaur. Credit: Jasmina Wiemann/Yale University
Dinosaur blood vessel with adjacent bone matrix that still contains bone cells. These structures have a perfect morphological preservation over hundreds of millions of years, but are chemically transformed through oxidative crosslinking. The extract comes from a sauropod dinosaur. Credit: Jasmina Wiemann/Yale University

A new study at the Yale suggested that burnt toast and dinosaur bones have a common trait- both consist of chemicals that transform original proteins into something new in right condition. Understanding this process could help scientists know how soft-tissue cells inside dinosaur bones can survive for hundreds of millions of years.

Dinosaur bones are much older, roughly 100 million years old, and they occasionally preserve organic structures similar to cells and blood vessels. Various attempts to resolve this paradox have failed to provide a conclusive answer.

Scientists, through this study, wanted to understand protein fossilization. They thus studied 35 samples of fossil bones, eggshells, and teeth to learn whether they preserve proteinaceous soft tissues, find out their chemical composition, and determine under what conditions they were able to survive for millions of years.

Scientists found that the soft tissues are preserved in samples from oxidative environments such as sandstones and shallow, marine limestones were transformed into Advanced Glycoxidation and Lipoxidation end products (AGEs and ALEs), which are resistant to decay and degradation.

They’re also structurally comparable to chemical compounds that stain the dark crust on toast. AGEs and ALEs are characterized by a brownish color that stains fossil bones and teeth that contain them. The compounds are hydrophobic, which means they are resistant to the normal effects of water and have properties that make it difficult for bacteria to consume them.

Scientists made their discovery using Raman microspectroscopy to decalcify fossils and image the released soft tissue structures. During this process, laser energy directed at the tissue causes molecular vibrations that carry spectral fingerprints for the chemicals that are present.

Co-author Derek Briggs, Yale’s G. Evelyn Hutchinson Professor of Geology and Geophysics and a curator at the Yale Peabody Museum of Natural History, said, “The study points to localities where soft tissue may be found in fossil bones, including sandstones deposited from rivers, dune sands, and shallow marine limestones.”

“Our results show how chemical alteration explains the fossilization of these soft tissues and identifies the types of environment where this process occurs. The payoff is a way of targeting settings in the field where this preservation is likely to occur, expanding an important source of evidence of the biology and ecology of ancient vertebrates.”

The research team includes scientists from Yale, the American Museum of Natural History, the University of Brussels, and the University of Bonn. The paper is presented in the journal Nature Communications.