RT Journal Article
SR Electronic
T1 Paradigm shift in eukaryotic biocrystallization
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.01.11.475817
DO 10.1101/2022.01.11.475817
A1 Jana Pilátová
A1 Tomáš Pánek
A1 Miroslav Oborník
A1 Ivan Čepička
A1 Peter Mojzeš
YR 2022
UL http://biorxiv.org/content/early/2022/01/11/2022.01.11.475817.abstract
AB Despite the widespread occurrence of crystalline inclusions in unicellular eukaryotes, scant attention has been paid to their composition, functions, and evolutionary origins, assuming just their inorganic contents. The advent of Raman microscopy, still scarcely used for biological samples, allowed chemical characterization of cellular inclusions in vivo. Using this method, herein we provide a substantial revision of the cellular crystalline inclusions across the broad diversity of eukaryotes examining all major supergroups. Surprisingly, here we show that 80 % of these crystalline inclusions contain purines, mostly anhydrous guanine (62 %), guanine monohydrate (2 %), uric acid (12 %) and xanthine (4 %). Hence, our findings indicate that purine biocrystallization is a very general and an ancestral eukaryotic process operating by an as-yet-unknown mechanism. Purine crystalline inclusions are high-capacity and rapid-turnover reserves of nitrogen of a great metabolic importance, as well as optically active elements, e.g., present in the light sensing eyespots of flagellates, possessing even more hypothetical functions. Thus, we anticipate our work to be a starting point for more in-depth studies of this phenomenon on the detailed level spanning from cell biology to global ecology, with further potential applications in biotechnologies, bio-optics or in human medicine.Competing Interest StatementThe authors have declared no competing interest.