References of "Javaux, Emmanuelle"
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See detailthe nitrogen-isotopic composition of 1.1 billion-year-old porphyrins reveals oceans dominated by phototrophic bacteria.
Brocks, Jochen; Gueneli, N; McKenna, AM et al

Conference (2019, September)

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See detailEarly traces of life: challenges and evidence
Javaux, Emmanuelle ULiege

Conference (2019, July 03)

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See detailEvolution and diversity of early Eukaryotes: insights from the Proterozoic of Arctic Canada
Loron, Corentin ULiege; Halverson, Galen; Rainbird, Robert et al

Poster (2019, May)

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See detailFirst Traces of Life: evidence and challenges
Javaux, Emmanuelle ULiege

Conference (2019, May)

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See detailEarly eukaryote Paleobiology and Evolution
Javaux, Emmanuelle ULiege

Scientific conference (2019, May)

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See detailEarly Traces of life
Javaux, Emmanuelle ULiege

Conference (2019, April)

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See detailEarly traces of life: evidence and challenges
Javaux, Emmanuelle ULiege

Conference (2019, March)

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See detailEarth Sciences misconceptions in origins of life
Javaux, Emmanuelle ULiege

Conference (2019, March)

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See detailEarly fungi from the Proterozoic era in Arctic Canada
Loron, Corentin ULiege; François, Camille; Rainbird, Robert et al

in Nature (2019)

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See detailCyanobacteria evolution: Insight from the fossil record
Demoulin, Catherine ULiege; Lara, Yannick ULiege; Cornet, Luc ULiege et al

in Free Radical Biology and Medicine (2019)

Cyanobacteria played an important role in the evolution of Early Earth and the biosphere. They are responsible for the oxygenation of the atmosphere and oceans since the Great Oxidation Event around 2.4 ... [more ▼]

Cyanobacteria played an important role in the evolution of Early Earth and the biosphere. They are responsible for the oxygenation of the atmosphere and oceans since the Great Oxidation Event around 2.4 Ga, debatably earlier. They are also major primary producers in past and present oceans, and the ancestors of the chloroplast. Nevertheless, the identification of cyanobacteria in the early fossil record remains ambiguous because the morphological criteria commonly used are not always reliable for microfossil interpretation. Recently, new biosignatures specific to cyanobacteria were proposed. Here, we review the classic and new cyanobacterial biosignatures. We also assess the reliability of the previously described cyanobacteria fossil record and the challenges of molecular approaches on modern cyanobacteria. Finally, we suggest possible new calibration points for molecular clocks, and strategies to improve our understanding of the timing and pattern of the evolution of cyanobacteria and oxygenic photosynthesis. © 2019 The Authors [less ▲]

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See detailAdaptations to extreme conditions: the strategy of the Antarctic cyanobacterium ULC007
Lara, Yannick ULiege; Durieu, Benoit ULiege; Javaux, Emmanuelle ULiege et al

Conference (2018, December 18)

In Polar regions, freshwater ecosystems range from cryoecosystems and ice shelf meltwater ponds to perennially ice-covered lakes where conspicuous benthic microbial mat communities constitute most of the ... [more ▼]

In Polar regions, freshwater ecosystems range from cryoecosystems and ice shelf meltwater ponds to perennially ice-covered lakes where conspicuous benthic microbial mat communities constitute most of the biomass. In these mats, cyanobacteria form the matrix in which other microorganisms can live, and where they are the key primary producers and main drivers of the carbon and food webs. To provide a better understanding of the survival strategies of Polar mat-forming cyanobacteria, we investigated the genome of a strain of the widely distributed Antarctic cyanobacterium, Phormidium priestleyi ULC007. We used high-throughput sequencing technologies to investigate its geographic distribution and genome evolution. More precisely, we investigated the abundance of genes involved in cold adaptation and circadian oscillation. In cold habitats, low temperatures lead to the success of particular organisms featuring adaptations to molecular and cellular disturbances such as higher rigidity of membranes, reduction of enzyme-catalyzed reactions, and reduction of solute transport. Our main results underline the importance of functional categories of genes involved in the production of key molecules for the survival of P. priestleyi in cold conditions (e.g. synthesis of exopolysaccharides, chaperone proteins, fatty acids and phospholipids). [less ▲]

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See detailBCCM/ULC: a collection of cyanobacteria linking Poles to Space
Wilmotte, Annick ULiege; Beets, Kim ULiege; Santoro, Mariano ULiege et al

Conference (2018, December 18)

The BCCM/ULC public collection funded by the Belgian Science Policy Office (BELSPO) aims to gather a representative portion of the cyanobacterial diversity with a focus on Polar biotopes (e.g. limnetic ... [more ▼]

The BCCM/ULC public collection funded by the Belgian Science Policy Office (BELSPO) aims to gather a representative portion of the cyanobacterial diversity with a focus on Polar biotopes (e.g. limnetic microbial mats, soil crusts, cryoconites, endolithes). It represents an exclusive Biological Resource Centre (BRC) where characterized polar cyanobacterial strains are available for researchers to study the taxonomy, biogeography, evolution, synthesis of secondary metabolites, adaptation to harsh environmental conditions, and genomic make-up. It currently holds 190 strains, including over 120 of Polar origin (online catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). Living cultures are regularly transferred, and the majority are also cryopreserved (as back-up), in order to assure their preservation and the rapid delivery of strains to clients for fundamental and applied research in both academia and industry. Genomic DNA is also available on request. The collection has obtained the ISO 9001:2015 certification for deposit and distribution of strains, as part of the multi-site certification for the Belgian Coordinated Collections of Microorganisms (BCCM) consortium. A polyphasic approach based on morphological and molecular identifications (based on SSU rRNA sequences) show that the strains belong to the Synechococcales, Oscillatoriales, Chroococcidiopsidales, Pleurocapsales, and Nostocales orders. This large diversity renders the BCCM/ULC collection particularly interesting for taxonomic, biogeographic and phylogenomic studies. Furthermore, the sequencing of the genomes of several strains has started. The BRC also aims to become a source for researchers to study further applications of cyanobacteria in astrobiology as shown by investigations of the resistance to desiccation and radiation of strains of Chroococcidiopsis sp. dominating rock-dwelling communities in extreme dry environments [1]. In paleontology, cyanobacteria represent model organisms thanks to their fundamental role in the oxygenation of the atmosphere and oceans during the Great Oxidation Event. Lastly, the mat-forming cyanobacterial strains may represent “critical organisms” in the investigation of the factors that determine the boundaries of microbial survival and growth on Earth and in the space environment, by virtue of the fact that they are components of microbial mat model systems which are more and more used to elucidate Earth’s past and the detection of life’s biosignatures. [less ▲]

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See detailEarly eukaryote Paleobiology and Evolution
Javaux, Emmanuelle ULiege

Conference (2018, November 21)

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See detailThe earliest evidence for modern-style plate tectonics recorded by HP–LT metamorphism in the Paleoproterozoic of the Democratic Republic of the Congo
François, Camille ULiege; Debaille, Vincianne ULiege; Paquette, Jean-Louis et al

in Scientific Reports (2018), 8(15452),

Knowing which geodynamic regimes characterised the early Earth is a fundamental question. This implies to determine when and how modern plate tectonics began. Today, the tectonic regime is dominated by ... [more ▼]

Knowing which geodynamic regimes characterised the early Earth is a fundamental question. This implies to determine when and how modern plate tectonics began. Today, the tectonic regime is dominated by mobile-lid tectonics including deep and cold subduction. However, in the early Earth (4.5 to 2 Ga) stagnant-lid tectonics may also have occurred. The study of high pressure–low temperature (HP–LT) metamorphic rocks is important, because these rocks are only produced in present-day subduction settings. Here, we characterize the oldest known HP–LT eclogite worldwide (2089 ± 13 Ma; 17–23 kbar / 500-550°C), discovered in the Democratic Republic of the Congo. We provide evidence that the mafic protolith of the eclogite formed at 2216 ± 26 Ma in a rift-type basin, and was then subducted to mantle depths (> 55 km) before being exhumed during a complete Wilson cycle lasting ca. 130 Ma. Our results indicate the operation of modern mobile-lid plate tectonics at 2.2–2.1 Ga. [less ▲]

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See detailBack to the past: a glance at microscopic marine diversity 1 billion year ago
Loron, Corentin ULiege; Javaux, Emmanuelle ULiege

Conference (2018, October 11)

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See detailThe BCCM/ULC collection of cyanobacteria in the spotlight at ULiège
Santoro, Mariano ULiege; Beets, Kim ULiege; Simons, Véronique et al

Poster (2018, October 11)

The ULC public collection of cyanobacteria belongs since 2011 to the consortium of Belgian Co-Ordinated Collections of Microorganisms (BCCM). It aims to conserve ‘ex situ’ a representative portion of the ... [more ▼]

The ULC public collection of cyanobacteria belongs since 2011 to the consortium of Belgian Co-Ordinated Collections of Microorganisms (BCCM). It aims to conserve ‘ex situ’ a representative portion of the biodiversity of cyanobacterial diversity of different origins, with a focus on Antarctic and Artic cyanobacteria isolated from terrestrial and aquatic ecosystems. BCCM/ULC currently holds 174 cyanobacterial strains that are available for researchers who study taxonomy, evolution, biogeography and the adaptation to harsh environmental conditions. The strains are identified by morphology and molecular characterization (based on rRNA sequences) and belong to the Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales orders. This large taxonomic distribution renders it a suitable reference point for phylogenomic and genomic make-up studies. Regular transfer of living cultures ensures the conservation of strains, whose majority are also cryopreserved in order to limit the genetic drift. BCCM/ULC obtained an ISO 9001:2015 certification for public and safe deposits, and for distribution of living strains and genomic DNA. The BCCM policy continuously aims to guarantee a safe fit-for-use microbiological material and data compliant with the rules on access and utilization of the Nagoya Protocol. In addition, BCCM/ULC provides, to clients from academia & industry, a service of morphological identification and molecular characterization, along with other scientific services as tailor-made trainings and collaborations. The public collection is progressively enriched by public deposits from other geographical areas and by incorporating the most interesting strains from the research collection of the host laboratory. The latter is also involved in the valorisation of the collection and collaborations, aiming to study the molecular mechanisms of adaptation to cold stress in polar strains, their production of potential bioactive compounds, to decipher and analyze their genomes and to determine the usefulness of their pigments as ‘traces of life’ in astrobiology. [less ▲]

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See detailLes Cyanobactéries, microscopiques mais fondamentales !
Javaux, Emmanuelle ULiege; Jacques, Philippe ULiege; Wilmotte, Annick ULiege

Scientific conference (2018, September 26)

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See detailArchean geodynamics and the onset of plate tectonics
Debaille, Vinciane; François, Camille ULiege; Javaux, Emmanuelle ULiege et al

Conference (2018, September)

Since the Archean (between 4 to 2.5 Gyr ago) was much hotter than the present time because of higher rates of internal heat production, it is traditionally accepted that the mantle was convecting faster ... [more ▼]

Since the Archean (between 4 to 2.5 Gyr ago) was much hotter than the present time because of higher rates of internal heat production, it is traditionally accepted that the mantle was convecting faster, resulting in faster mixing time and also plates at the surface of the Earth moving faster. Short-lived isotope systems are particularly adapted to understand the geological processes that occurred during the Archean because their production stopped at some point in the past and only mixing can subsequently modify them. As such, the system 146Sm-142Nd where 146Sm was extinct ~0.5 Gyr after the formation of the solar system is particularly useful to investigate the Earth’s early geodynamics. By using this system, we found a resolvable positive anomaly of µ142Nd = + 7 ± 3 ppm in a 2.7 Gyr old tholeiitic lava flow from the Abitibi Greenstone Belt indicating that early mantle heterogeneities formed between 4 and 4.5 Gyr persisted ~1.8 Gyr after Earth’s formation [1]. This result contradicts the expected rapid early (~0.1 Gyr) [2, 3], as well as the slower recent (~1 Gyr) mixing rates in the convecting mantle [3-5]. We developed a numerical modelling [1, 6] which suggests that inefficient convective mixing can occur even in a highly convective mantle in absence of plate tectonics, i.e. in a stagnant-lid regime. Our model allows only sporadic and short subduction episodes throughout the Hadean and Archean in order to explain the long-term preservation of chemical anomalies in a highly convective mantle. Modern subduction is characterized by (U)HP-LT metamorphism resulting eclogite-facies rocks. Eclogites are absent from the Archean record, hence corroborating the absence of modern-style subduction zones. On the other hand, we will also present the oldest evidence of HP-LT eclogite at 2.1 Gyr from the Congo craton, which is a clear indicator that the 2.7-2.1 Gyr period was a turning point for the onset of modern plate tectonics on Earth [7]. References: [1] Debaille, et al. (2013), Earth Planet. Sci. Lett., 373, 83-92. [2] van Keken and Zhong (1999), Earth Planet. Sci. Lett., 171 533-547. [3] Coltice and Schmalzl (2006), Geophys. Res. Lett., 33, L23304. [4] Kellogg and Turcotte (1990), J. Geoph. Res., 95, 421-432. [5] Allègre, et al. (1995), Geophys. Res. Lett., 22, 2325-2328. [6] O'Neill, et al. (2013), American Journal of Science, 313, 912-932. [7] François, et al. in review. [less ▲]

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