Guest post by Addie Jackson, North Carolina School of Science and Mathematics
Ask Keely Glass how she would describe her research to a third grader, and she laughs while thinking of the best way to explain.
“So, say you’re sitting next to your friends. One has really black hair and one has red hair. They have different hair colors, because their hair colors come from the different pigments. Your friend with black hair has more eumelanin, while your friend with red hair has pheomelanin.”
A PhD candidate in the chemistry department at Duke, Glass currently does research on analytical methods to analyze these pigments in biological and historical samples. She’s also using those skills to provide direct chemical evidence for the presence and preservation of eumelanin in the fossil record.
Glass elaborates by describing a common fascination with squids, also known as cephalopods, who release pure black eumelanin when faced with a predator. Two kinds of melanin are present in nature: eumelanin (brown to black in color) and pheomelanin (yellow to red). Through her work, she and her team have verified that eumelanin is preserved in the fossil record, and showed that it can be identified directly using its known chemical signature. They have also found that the eumelanin identified in the fossil record is not significantly different from the modern eumelanin, meaning it hasn’t evolved in the more than 160 million years since.
Another lab at Duke, run by Professor Warren S. Warren, uses a pump-probe microscopy system to characterize melanins to attempt to find statistically significant variations between melanomas (skin cancers) that do not develop metastases. The hope for this project is to improve diagnostic accuracy for these metastatic melanomas, through analyzing the melanin distribution in “old” archived (stored for >10 years) tissue samples. Glass says, “The paper I wrote with them essentially says if melanin resists degradation (stays intact and doesn’t alter) over more than 160 million years, it’s fairly clear that it will resist degradation in storage for 10 years. In other words, it’s pretty clear that these archived tissue samples are still viable for melanin analysis.”
Working with the Warren group, Glass also found that the pump-probe system was sensitive to the higher iron-concentration fossilized squid melanin as compared with modern cephalopod melanin. They were able to mirror the iron-independent signal by adding iron to modern cephalopod melanin. This proved to be interesting because metastatic melanomas have increased iron levels, which may or may not be responsible for signature variations.
The classical fields of chemistry (analytical, organic, physical, theoretical, inorganic, and biological) have become more integrated over time, making the labels themselves increasingly obsolete. To better label themselves, most chemists mix and match: “I’ve called myself at various times a ‘Bioanalytical Chemist,’ ‘Biophysical Organic Chemist,’ ‘Analytical Biochemist,’ ‘Organic Geochemist’ etc. to emphasize that the systems I’ve worked on, the techniques I’ve used, and the skills I’ve obtained are diverse and dependent on the project I’m defining.”
Glass says, “When I think that the names have gone a little haywire, I jokingly call myself an omni-chemist. Like most chemists I work on diverse array of projects that require techniques and knowledge from many fields.”
Addie Jackson interviewed Keely Glass and wrote this post as part of a Science Communication seminar led by NCSSM Dean of Science Amy Sheck.