References of "Javaux, Emmanuelle"
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See detailRaman characterization of the UV-protective pigment gloeocapsin and its role in the survival of cyanobacteria
Storme, Jean-Yves ULg; Golubic, Stjepko; Wilmotte, Annick ULg et al

in Astrobiology (in press)

Extracellular UV-screening pigments gloeocapsin and scytonemin present in the EPS envelopes of extremophile cyanobacteria of freshwater and marine environments were studied by Raman spectroscopy and ... [more ▼]

Extracellular UV-screening pigments gloeocapsin and scytonemin present in the EPS envelopes of extremophile cyanobacteria of freshwater and marine environments were studied by Raman spectroscopy and compared to their intracellular photosynthetic pigments. This Raman spectral analysis of the extracellular pigment gloeocapsin showed that it shared Raman spectral signatures with parietin, a radiation-protective pigment known in lichens. The UV-light spectra also showed similarities. Gloeocapsin occurs in some cyanobacterial species, mostly with exclusion of scytonemin, indicating that these pigments have evolved in cyanobacteria as separate protective strategies. Both gloeocapsin and scytonemin are widely and species-specifically distributed in different cyanobacterial genera and families. The widespread occurrence of these pigments may suggest an early origin, while their detection by Raman Spectroscopy makes them potential biosignatures for cyanobacteria in the fossil record and demonstrates the usefulness of non-destructive Raman spectroscopy analyses for the search of complex organics, including possible photosynthetic pigments, if preservable in early Earth and extraterrestrial samples. [less ▲]

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See detailContribution of cyanobacteria to the building of travertines in a calcareous stream
Wilmotte, Annick ULg; Golubic, Stjepko; Kleinteich, Julia et al

Poster (2015, August 03)

The ambient temperature travertine deposits of the calcareous Hoyoux River (Modave, Belgium) and several tributaries are organized and promoted by the filamentous cyanobacterium identified by its ... [more ▼]

The ambient temperature travertine deposits of the calcareous Hoyoux River (Modave, Belgium) and several tributaries are organized and promoted by the filamentous cyanobacterium identified by its morphotype and ecological properties as Phormidium cf. incrustatum. A combination of techniques was used to study this biotope: physico-chemical parameters and CO2 measurements, Scanning and Transmission Electron Microscopy, RAMAN microspectroscopy. A molecular diversity study with pyrosequencing of the cyanobacterial 16S rRNA is in progress. A potential candidate was isolated in culture. [less ▲]

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See detailEarly evolution of large microorganisms with cytological complexity revealed by microanalyses of 3.4 Ga organic-walled microfossils.
Sugitani; Mimura, K; Takeuchi, M et al

in Geobiology (2015)

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See detailCyanobacteria - the constructors of travertines?
Kleinteich, Julia; Stelmach Pessi, Igor ULg; Velazquez, David et al

Conference (2015, February)

Cyanobacteria are participating in carbonate build-up and travertine formation in the Belgian river Hoyoux and its tributaries. In this study, we sampled calcareous material from travertines and oncoliths ... [more ▼]

Cyanobacteria are participating in carbonate build-up and travertine formation in the Belgian river Hoyoux and its tributaries. In this study, we sampled calcareous material from travertines and oncoliths from four sampling sites on the Hoyoux river and Triffoy brook. In addition, the water chemistry was determined. The structure of the material was analyzed by Scanning Electron Microscopy and Raman microscopy (?°. The dominant cyanobacterial species was isolated and identified on the basis of microscopic observation and amplification of the 16S-ITS fragment as Phormidium sp., likely functioning as the ‘architect’ of the travertine system. In order to describe the full diversity of the travertine system and to discriminate between the active fraction and inactive or dead organic matter, DNA as well as RNA was extracted from the travertine material, amplified using cyanobacteria specific primers and sequenced by 454 pyrosequencing. To detect seasonal changes in the biological activity, summer and winter time points were compared. This study reveals the ecology of an overlooked environment in Belgian river systems and tries to explain the build-up of travertines. [less ▲]

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See detailTowards a palaeoecological model of the Mesoproterozoic Taoudeni basin
Beghin, Jérémie ULg; Poulton, Simon; Gueneli, Nur et al

Conference (2015)

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See detailSpecie-specific intracellular iron biomineralization in a 1.9 Ga microfossil assemblage
Lepot, kevin; Addad, Ahmed; Knoll, AH et al

Conference (2015)

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See detailBiostratigraphic and chemostratigraphic constraints of the Mbuji-Mayi Supergroup, Democratic Republic of Congo
Kabamba Baludikay, Blaise ULg; Bekker, Andrey; Baudet, Daniel et al

Poster (2014, December 16)

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See detailBIODIVERSITY AND REDOX CONDITIONS THROUGH THE PROTEROZOIC TAOUDENI BASIN OF MAURITANIA
Beghin, Jérémie ULg; Poulton, Simon; Gueneli, Nur et al

Scientific conference (2014, November 03)

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See detailBiostratigraphic and chemostratigraphic constraints of the Mbuji-Mayi Supergroup (Meso-Neoproterozoic age), Democratic Republic of Congo.
Kabamba Baludikay, Blaise ULg; Bekker, Andrey; Baudet, Daniel et al

Conference (2014, November 03)

The Mbuji-Mayi Supergroup is a sedimentary sequence unaffected by regional metamorphism [1]. It was deposited between 1174 ± 22 Ma and ca. 800 Ma in the intracratonic failed-rift SMLL “Sankuru-Mbuji-Mayi ... [more ▼]

The Mbuji-Mayi Supergroup is a sedimentary sequence unaffected by regional metamorphism [1]. It was deposited between 1174 ± 22 Ma and ca. 800 Ma in the intracratonic failed-rift SMLL “Sankuru-Mbuji-Mayi- Lomami- Lovoy” basin [2] which extends from SE to NW between Katanga and Kasai Provinces. And overlies the Mesoproterozoic Kibaran Belt Supergroup (in the eastern part of SMLL basin) while in the Western part, where we focused our work, it rests unconformably upon Archean Dibaya Granitic Complex [3]. The amygdaloidal basaltic pillow lavas (948 ± 20 Ma) overlie the Mbuji-Mayi Supergroup, at the confluence of Mbuji-Mayi and Sankuru rivers [4]. Lithostratigraphically, this Supergroup consists in two distinct successions: a lower siliciclastic sequence (~500m) of BI Group and an upper carbonatic sequence (~1000m) with stromatolitic build-ups and black shales of BII Group [2]. Our own and previous sedimentological observations [5] indicate facies ranging from subtidal, low-energy stromatolitic environments to overlying intertidal to supratidal evaporitic settings of lagoon and sabkha. Here we present data on microfossil diversity and carbon isotope chemostratigraphy from the Kanshi, Lubi and Kafuku drillholes. The well-preserved and diverse assemblage of acritarchs and filamentous forms includes prokaryotes and eukaryotes, and is similar to other coeval assemblages described worldwide outside of Africa. The presence of the acanthomorph acritarch Trachyhystrichosphaera aimika is significant as it is indicative of the late Meso- to early Neoproterozoic age elsewhere, and is reported for the first time in Central Africa. So far, 56 species belonging to 31 genera were identified, dramatically increasing the previously reported diversity [6, 7]. Chemostratigraphy based on δ13Ccarb values for 290 samples, records, for the BI Group, predominantly negative values down to -8 to -9 ‰ VPDB with few samples having more positive, up to +3 ‰, values. Although the siliciclastics-rich sediments in the lower part of the BI Group likely record early diagenetic signal, carbonates in the upper part of the BI Group show similar patterns in both the Lubi and Kafuku drill cores with the sharp fall from +1 to +3 ‰ values to -8 to -7 ‰ and recovery back to +1 ‰ values over 40 to 70 m of section. The BII Group shows a less dramatic rise from -1 ‰ to +4 to +5 ‰ over more than 150 m of section. These large-scale variations differ from the steady-state carbon cycle of the late Mesoproterozoic [8] and are typical of the early Neoproterozoic record [9]. The project is supported by the EU FP7 ERC Stg ELITE. [less ▲]

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See detailBIODIVERSITY AND REDOX CONDITIONS THROUGH THE PROTEROZOIC TAOUDENI BASIN OF MAURITANIA
Beghin, Jérémie ULg; Poulton, Simon; Gueneli, Nur et al

Conference (2014, September)

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See detailOrganic and mineral imprints in fossil photosynthetic mats of an East Antarctic lake
Lepot, Kevin; Compère, Philippe ULg; Gerard, E et al

in Geobiology (2014), 12(5), 424-450

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See detailA Phylogenomic analysis of the origin of plastids
Cornet, Luc ULg; Javaux, Emmanuelle ULg; Wilmotte, Annick ULg et al

Conference (2014, June 24)

Cyanobacteria are a morphologically diverse phylum, with their first occurrence dating from the Precambrian. Oxygenic photosynthesis appeared in this group during the same geological period. Several ... [more ▼]

Cyanobacteria are a morphologically diverse phylum, with their first occurrence dating from the Precambrian. Oxygenic photosynthesis appeared in this group during the same geological period. Several publications have established, without any doubt, that plastids (both primary and complex) form a monophyletic ensemble emerging from Cyanobacteria. However, the exact position of plastids within Cyanobacteria is still uncertain, with several recent papers leading to very different hypotheses. Here we present a phylogenomic analysis of the origin of plastids. Our study takes advantage of all the available genomes and thus represents the best taxonomic sampling seen so far: 140 genomes of Cyanobacteria, 101 genomes of plastids and 27 outgroups taken in Melainabacteria and Chloroflexi. It results in an analysis using state-of-the-art methods (e.g., orthology assessment using USEARCH and OrthoMCL, phylogenetic inference using CAT and CAT-GTR models) based on more than 160 protein alignments totalizing over 20,000 unambiguously aligned amino acids. To confirm our results, we performed gene jackknife inferences and gene reconciliation analyses on the same dataset. We expect that out approach accounts for potential phylogenetic artefacts due to changes in the evolutionary process having occurred when the guest cyanobacterium became an endosymbiont and eventually a plastid. Meanwhile, we improve the phylogeny of Cyanobacteria per se, notably because of the presence of Melainabacteria in our dataset. [less ▲]

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See detailMicrofossils’ diversity from the Proterozoic Taoudeni Basin, Mauritania
Beghin, Jérémie ULg; Javaux, Emmanuelle ULg; Houzay, Jean-Pierre et al

in European Geosciences Union General Assembly 2014 Vienna, Austria, 27 April – 02 May 2014 (abstract book) (2014, April 27)

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See detailMicropaleontology and chemostratigraphy of the Neoproterozoic Mbuji-Mayi Supergroup, Democratic Republic of Congo.
Kabamba Baludikay, Blaise ULg; Bekker, Andrey; Baudet, Daniel et al

in Geophysical Research Abstracts (2014), 16(EGU2014),

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See detailThe « boring billion » : an exciting time for early eukaryotes !
Javaux, Emmanuelle ULg; Beghin, Jérémie ULg; Houzay, JP et al

Conference (2013, August)

Detailed reference viewed: 58 (12 ULg)