Session: Parallel session 5 - New topics in OMICs

Ultra-high-resolution mass spectrometry applied to micropalaeontology

Mathilde BON^1,2,3, Christian ROLANDO ⁴, Cristian FOCSA³, Thijs VANDENBROUCKE², Kevin LEPOT^1,8, Yvain CARPENTIER³, Fabrice BRAY ⁴, Armelle RIBOULLEAU ¹, François BAUDIN ⁶, Nicolas NUNS⁵, Ilwan MEIGNANT⁷, Maxime BRIDOUX⁷

¹Univ. Lille, CNRS, Univ. Littoral Côte d’Opale, IRD, UMR 8187 – LOG – Laboratoire d’Océanologie et de Géosciences, Lille, France
²Department of Geology (WE13), Ghent University, Gent, Belgium
³Univ. Lille, CNRS, UMR 8523 – PhLAM – Physique des Lasers Atomes et Molécules, Lille, France
⁴Univ. Lille, CNRS, USR 3290 – MSAP – Miniaturisation pour la Synthèse, l’Analyse et la Protéomique, Lille, Belgium
⁵Univ. Artois, FR 2638 -IMEC - Institut Michel-Eugène Chevreul, Lille, France
⁶SU CNRS, ISTeP UMR 7193, Paris, France
⁷CEA, DAM, DIF, Arpajon, France
⁸Institut Universitaire de France (IUF), Paris, France

We study Gloeocapsomorpha prisca as a model microfossil species to develop new mass spectrometry (MS) methods that could help assess biological affinities in deep time. G. prisca comprise up to 99% of the organic matter in a 460 million years old rock from northwest Russia6, thus allowing invaluable comparisons between bulk and microscale analytical techniques. G. prisca is a probable cyanobacterium^1,3,4,7. It will be compared with Tasmanites an unicellular prasinophyte green alga which come from a 419 million years old rock from western Libya⁵.

We use ultra-high-resolution MS methods to decipher the composition of these microfossils. These are laser desorption/ionization by Fourier transform ion cyclotron resonance MS (LDI-FT-ICR-MS) and pyrolysis-direct real-time analysis-MS (pyro-DART-MS).

LDI-FTICR-MS spectra for G. prisca show a dominance of oxygenated aromatics, nitrogen compounds and aromatic hydrocarbons. For Tasmanites, aromatic compounds with one N dominate strongly.TD-pyro-DART-MS also shows aliphatic oxygenated molecules for G. prisca (C₂₀H₃₇O₂, C₁₅H₂₅O₂...).

The predominance of oxygenated functions in LDI-FT-ICR-MS and TD-pyro-DART-MS is consistent with the composition of G. prisca analyzed by (micro)pyrolysis and chemolysis^1,2,3. The observation of significant differences between G. prisca and Tasmanites in LDI-FT-ICR-MS highlights the potential of this method to distinguish the molecular compositions of biopolymer derivatives in individualized cells.

¹Blokker P. et al.(2001) DOI: 10.1016/S0016-7037(00)00582-2

²Derenne S. et al.(1990) DOI : 10.1016/0146-6380(90)90124-I

³Derenne S. et al.(1992). DOI:10.1016/0146-6380(92)90001-E

⁴Kiipli E. and Kiipli T.(2013) DOI: 10.3176/oil.2013.1.06

⁵Le Hérissé A. et al.(2002) DOI: 10.1016/S0034-6667(01)00123-3

⁶Raevskaya E. et al.(2004) palynomorphs associated with kukersite deposits

⁷da Silva T. F. D. et al.(2016) DOI: 71–79. 10.1016/j.coal.2016.08.010