Metallomics in geological time: trace element biosignatures evidence the influence of ocean chemistry on Earth’s earliest ecosystems

We used a combination of techniques: microbeam particle-induced X-ray emission spectroscopy (PIXE), carbon isotope geochemistry and electron microscopy. This has allowed us to discover trace element signatures of life in 3.33 billion-year-old rocks from South Africa. These signatures support a long-standing hypothesis that biological dependency on trace elements results from the enrichment of these elements in the metal-rich, hydrothermally influenced habitats of early life.

We approached this challenge through the biological concept of the metallome, which refers to the entirety of the inorganic species (metal and metalloid) within a cell. Although the genome and proteome do not survive fossilisation over billions of years, it is probable that metal concentrations within carbonaceous materials could do so, and indeed we found this to be the case in numerous carbon-rich microstructures from the Josefsdal Chert.

We found that a range of elements crucial to anaerobic microbes, including Fe, V, Ni, As and Co, were enriched within carbonaceous material characterised by negative carbon isotope signatures indicating biological origins.

Palaeo-metallome compositions could be used to deduce the metabolic networks of Earth’s earliest ecosystems and, potentially, as a biosignature for the evaluation of organic materials found on Mars.

The article “Metallomics in deep time and the influence of ocean chemistry on the metabolic landscapes of Earth’s earliest ecosystems” released March 18th in Scientific Reports.

Contact: keyron.hickman-lewis@cnrs.fr; frances.westall@cnrs.fr

 

DECLICS

On January 17, 2020, rich exchanges took place between the thematic group "Metal Complexes and MRI" and students of the first and final European class of the Lycée Pothier in Orleans as part of DECLICS "Dialogues Entre Chercheurs et Lycéens pour les Intéresser à la Construction des Savoirs" .

13th Workshop of the “Vectorization, Imaging and Radiotherapy” network of Cancéropôle Grand Ouest – Le Bono, 2019, September 25-28th

The 13th international workshop edition will focus on the latest advances in imaging techniques: PET, SPECT, MRI, US, Infra-red Bioluminescence, Fluorescence, Photoacoustic, CyTof Imaging, Microscopy, Spectroscopy and Raman Imaging.

It aims to address innovative developments in chemistry (synthesis of tracers, chelates, contrast agents, fluorescent probes, etc.), biology (identification of new tumour targets, etc.) and physics (instrumentation, methodological aspects of image analysis, radiomics ...)

The workshop will confront the points of view and problems of the various disciplines, Chemistry, Biology, Physics, Medicine, working for the development of imaging in Oncology.

Overview lectures will be given by experts in the different scientific fields targeted by the workshop. A number of selected oral presentations given by young researchers will complete the different scientific sessions.

This workshop aims at sharing scientific results and at facilitating exchanges between experienced and young researchers in a fast advancing field. The place of the congress was chosen in order to stimulate intense discussions between young and senior scientists.

See workshop site