Publications of Yannick Lara
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See detailPhototrophic green algae in Mid-Proterozoic oceans
Sforna, Marie-Catherine ULiege; Loron, Corentin ULiege; Demoulin, Catherine ULiege et al

Poster (2020, January)

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See detailBiodiversity of Cyanobacteria and associated microbiome in the BCCM/ULC Culture Collection
Ahn, Anne-Catherine ULiege; Cornet, Luc ULiege; Beets, Kim ULiege et al

Poster (2019, October 18)

Cyanobacteria are a phylum of photosynthetic bacteria that played an important role in the evolution of the planet by oxygenating its early atmosphere and provoking the Great Oxydation Event around 2.3 ... [more ▼]

Cyanobacteria are a phylum of photosynthetic bacteria that played an important role in the evolution of the planet by oxygenating its early atmosphere and provoking the Great Oxydation Event around 2.3 billion years ago. Early cyanobacteria were the ancestors of plastids and thus, at the origin of the highly successful algae and plants. Nowadays, they still are the basis of the food chain in many biotopes, as long as there is liquid water, light, air and some minerals. Some cyanobacterial taxa are very resistant to harsh environmental conditions, and thus, grow in polar, hypersaline, alkaline and/or arid biotopes, but also in spatial conditions. Furthermore, they are also a prolific source of secondary compounds with bioactivies. The BCCM/ULC public collection funded by the Belgian Science Policy Office since 2011 presently includes 224 cyanobacterial strains, with 140 being of Antarctic origin (catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). The strains are unicyanobacterial but not axenic, due to the well known difficulties of purifying them. Morphological identification showed that the strains belong to the orders of Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. Furthermore, 16S rRNA and ITS sequences of the strains are being characterized. Recent sequencing efforts increased the amount of available 16S rRNA sequences of BCCM/ULC strains to 190. Those sequences belong to 75 OTUs (groups of sequences with > 99 % 16S rRNA similarity), which represents a quite large diversity. To better characterize the microbiome of the cultures, a metagenomic analysis was performed for 12 polar or subpolar strains and three temperate ones, including three early-branching organisms that will be useful for phylogenomics. The design of a specific metagenomic pipeline enabled the easy recovery of the cyanobacterial genomes from the non-axenic cultures. In parallel, 31 genomes of co-cultivated bacteria (12 nearly complete) from the same cultures were determined. They mostly belonged to Bacteroidetes and Proteobacteria, some of them being very closely related, in spite of sometimes geographically distant sampling sites (Cornet et al. 2018). In summary, the BCCM/ULC public collection serves as a Biological Resource Centre to conserve ex situ and document the biodiversity of cyanobacteria and their microbiomes, as well as a repository for discovery of novel bioactive compounds. Cornet, L., Bertrand, A., Hanikenne, M., Javaux, E., Wilmotte, A., & Baurain, D. (2018). Metagenomic assembly of new (sub)polar Cyanobacteria and their associated microbiome from non-axenic cultures. Microbial Genomics.4. DOI 10.1099/mgen.0.000212. [less ▲]

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See detailAntarctic cyanobacteria sources of biosignatures
Lara, Yannick ULiege; Demoulin, Catherine ULiege; Lambion, Alexandre ULiege et al

Conference (2019, September 05)

The high UV intensities and extreme seasonality make some of Antarctic habitats interesting to the study life adaptive strategies in extreme conditions, and the biosignatures that can be preserved. In ... [more ▼]

The high UV intensities and extreme seasonality make some of Antarctic habitats interesting to the study life adaptive strategies in extreme conditions, and the biosignatures that can be preserved. In Antarctica, most of the surface, lacustrine and endolithic photosynthetic niches are occupied by cyanobacteria, which are well equipped to survive cold, desiccation or UV exposure. To provide a better understanding of the cyanobacteria survival strategies to extreme conditions, we used transmitted light and TEM microscopy as well as high-throughput sequencing technologies on the Antarctic lineage Phormidesmis priestleyi. We observed and characterized the production of a gloeocapsin-like UV-screening pigment and compared it to the pigment produced by Gloeocapsa alpina. Cyanobacteria are considered to be the inventors of oxygenic photosynthesis and therefore played a pivotal role in early Life and Earth evolution during the Precambrian. However, to perform photosynthesis in the UV exposure of the Early Earth unprotected by an ozone layer, their ancestors must have developed multiple molecular strategies. The presence of a gloeocapsin-like pigment in different cyanobacterial lineages may suggest its early production by their common ancestor, potentially present before the oxidation of the atmosphere. In Polar regions, low temperatures lead to the success of particular organisms featuring adaptations to molecular and cellular disturbances such as rigidity of membranes, reduction of enzyme-catalyzed reactions, and solute transport. Our results underline the importance of functional categories of genes involved in the production of key molecules for the survival of polar P. priestleyi (e.g. exopolysaccharides, chaperone proteins, fatty acids and phospholipids). The study of Antarctic cyanobacteria is promising to find new analog biosignatures for Life in rocky habitable planets. This project is supported by the mini-ARC PUMA (ULiège, Belgium). [less ▲]

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See detailCharacterization of a non-toxic pyomelanin pigment produced by the yeast Yarrowia lipolytica
Ben Tahar, Imen ULiege; Kus-Liśkiewicz, Małgorzata; Lara, Yannick ULiege et al

in Biotechnology Progress (2019)

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See detailBCCM/ULC : genomic research on Polar cyanobacteria
Wilmotte, Annick ULiege; Beets, Kim ULiege; Simons, Véronique et al

in European Journal of Phycology (2019, August 27), 54(sup1), 31-117

The BCCM/ULC public collection of cyanobacteria aims to gather a representative portion of Polar cyanobacterial diversity from different ecological origins (microbial mats, soil crusts, cryoconites ... [more ▼]

The BCCM/ULC public collection of cyanobacteria aims to gather a representative portion of Polar cyanobacterial diversity from different ecological origins (microbial mats, soil crusts, cryoconites, endoliths, etc.) and ensure their ex-situ conservation in a context of global change. These strains are available for researchers to study the biodiversity, taxonomy, evolution, adaptations to harsh environmental conditions, and genomic make-up of Polar cyanobacteria. Currently, there are 120 unicyanobacterial strains of Polar origin in the collection (catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). The collection is ISO 9001 certified for depositing and distributing strains, as part of the multi-site certification of the Belgian Co-ordinated Collections of Micro-organisms (BCCM) consortium. Morphological and molecular identification (based on 16S rRNA sequences) indicate that the strains belong to the orders Chroococcales, Chroococcidiopsidales, Nostocales, Oscillatoriales, Pleurocapsales, and Synechococcales. This broad genotypic distribution makes the BCCM/ULC collection particularly interesting for phylogenomic studies. The first genome of an axenic Antarctic strain, Phormidesmis priestleyi ULC007, was sequenced. To investigate the occurrence of genes involved in the cold stress response, a selection of 42 PEGs (protein encoding genes) linked to cold adaptation was studied in 72 cyanobacterial genomes. By comparing the genes copy numbers as a proxy of adaptation, our results underline the importance of different functions in the adaptation mechanisms to the polar environment (e.g. DNA repair, Heat shock proteins, EPS biosynthesis). We also described a metagenomic pipeline that enables the easy recovery of genomes from non-axenic cultures, tested on 17 cyanobacterial strains from the BCCM/ULC collection. In parallel, we assembled 31 co-cultivated bacteria (12 nearly complete) from the same cultures and showed that they mostly belong to Bacteroidetes and Proteobacteria. [less ▲]

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See detailCyanobacteria of Polar Regions: Focus of the BCCM/ULC Culture Collection
Ahn, Anne-Catherine ULiege; Beets, Kim ULiege; Lara, Yannick ULiege et al

Poster (2019, June 13)

In the Polar Regions, Cyanobacteria represent key primary producers and are the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. They build benthic microbial mats in lakes ... [more ▼]

In the Polar Regions, Cyanobacteria represent key primary producers and are the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. They build benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They may present interesting features to survive freeze/thaw cycles, seasonally contrasted light intensities, high UV radiations, dessication and other stresses. The BCCM/ULC public collection funded by the Belgian Science Policy Office since 2011 aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic mats, soil crusts, cryoconites, endoliths…). It makes it available for researchers to study the taxonomy, evolution, adaptations to harsh environmental conditions, and genomic make-up. It presently includes 224 cyanobacterial strains, with 140 being of Antarctic origin (catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). An ISO 9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. The morphological identification shows that the strains belong to the orders Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. The 16S rRNA and ITS sequences of the strains are gradually being characterized. The 159 BCCM/ULC strains for which 16S rRNA sequences were analyzed correspond to 69 OTUs (sequences with > 99 % 16S rRNA similarity), and thus, represent a quite large diversity. In addition, cyanobacteria are known to produce a wide range of secondary metabolites (e.g. alkaloids, cyclic and linear peptides, polyketides) with bioactive potential. Genome sequencing was performed for 15 strains (Lara et al. 2017, Cornet et al. 2018). The bioinformatic analysis of the partial genomes of strains ULC007, ULC065 and ULC129 showed the presence of clusters encoding NRPS, PKS, hybrid clusters and other types of secondary metabolites. The comparison of a selection of the PEGs involved in the cold adaptation mechanisms revealed that more copies of PEGs involved in various molecular mechanisms of cold stress responses have been found in polar than in non polar genomes. In summary, the BCCM/ULC public collection serves as a Biological Resource Centre to conserve ex situ and document the biodiversity of polar cyanobacteria, as well as a repository for discovery of novel bioactive compounds. [less ▲]

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See detailMarked Succession of Cyanobacterial Communities Following Glacier Retreat in the High Arctic
Pessi, Igor S; Puschkareva, Ekaterina; Lara, Yannick ULiege et al

in Microbial Ecology (2019), 77

Cyanobacteria are important colonizers of recently deglaciated proglacial soil but an in-depth investigation of cyanobacterial succession following glacier retreat has not yet been carried out. Here, we ... [more ▼]

Cyanobacteria are important colonizers of recently deglaciated proglacial soil but an in-depth investigation of cyanobacterial succession following glacier retreat has not yet been carried out. Here, we report on the successional trajectories of cyanobacterial communities in biological soil crusts (BSCs) along a 100-year deglaciation gradient in three glacier forefields in central Svalbard, High Arctic. Distance from the glacier terminus was used as a proxy for soil age (years since deglaciation), and cyanobacterial abundance and community composition were evaluated by epifluorescence microscopy and pyrosequencing of partial 16S rRNA gene sequences, respectively. Succession was characterized by a decrease in phylotype richness and a marked shift in community structure, resulting in a clear separation between early (10–20 years since deglaciation), mid (30–50 years), and late (80–100 years) communities. Changes in cyanobacterial community structure were mainly connected with soil age and associated shifts in soil chemical composition (mainly moisture, SOC, SMN, K, and Na concentrations). Phylotypes associated with early communities were related either to potentially novel lineages (< 97.5% similar to sequences currently available in GenBank) or lineages predominantly restricted to polar and alpine biotopes, suggesting that the initial colonization of proglacial soil is accomplished by cyanobacteria transported from nearby glacial environments. Late communities, on the other hand, included more widely distributed genotypes, which appear to establish only after the microenvironment has been modified by the pioneering taxa. [less ▲]

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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), 140

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 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 detailEx-situ conservation and exploration of polar cyanobacteria in the BCCM/ULC Collection
Wilmotte, Annick ULiege; Santoro, Mariano; Beets, Kim ULiege et al

Poster (2018, October)

The BCCM/ULC public collection funded by the Belgian Science Policy Office since 2011 aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins ... [more ▼]

The BCCM/ULC public collection funded by the Belgian Science Policy Office since 2011 aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.). It makes it available for researchers to study the taxonomy, evolution, adaptations to harsh environmental conditions, and genomic make-up. It presently includes 174 cyanobacterial strains, with more than half being of polar origin (catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). [less ▲]

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See detailThe MIDICHIP database
Lara, Yannick ULiege; Wilmotte, Annick ULiege

Report (2018)

In order to be protected, biodiversity must be evaluated. For cyanobacteria, the traditional morphological measures of biodiversity are unsatisfactory. We utilize molecular markers (like SSU rRNA) to ... [more ▼]

In order to be protected, biodiversity must be evaluated. For cyanobacteria, the traditional morphological measures of biodiversity are unsatisfactory. We utilize molecular markers (like SSU rRNA) to define taxa on the basis of phylogeny. In freshwater ecosystems huge populations of cyanobacteria can occur. These blooms may release toxins that make the water poisonous. A second part of the study is to compare the temporal dynamics of biodiversity in both natural and disturbed lakes. This comparative analysis requires the use of ecological indexes to summarise the diversity of the samples and allow inferences about the ecosystem to be made. [less ▲]

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See detailBCCM/ULC: a unique Biological Resource Center of (sub)polar cyanobacteria
Santoro, Mariano ULiege; Beets, Kim ULiege; Lara, Yannick ULiege et al

Poster (2018, September 13)

The BCCM/ULC public collection of cyanobacteria funded by the Belgian Science Policy Office (BELSPO) focusses on the ‘ex situ’ conservation of a representative portion of the (sub)polar cyanobacterial ... [more ▼]

The BCCM/ULC public collection of cyanobacteria funded by the Belgian Science Policy Office (BELSPO) focusses on the ‘ex situ’ conservation of a representative portion of the (sub)polar cyanobacterial diversity with different origins, isolated from terrestrial (e.g. soil crusts, cryoconites, endoliths) and aquatic ecosystems (e.g. limnetic microbial mats, freshwater lakes and marine environments). BCCM/ULC currently holds 175 cyanobacterial strains, including over 100 of polar origin (catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). The strains are available for researchers who study the taxonomy, evolution, biogeography, adaptation to harsh environmental conditions, etc. Morphological and molecular identifications (based on SSU rRNA sequences) indicate that the strains belong to the orders Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. This large taxonomic distribution makes the collection interesting for phylogenomic and genomic make-up studies, hence the genome sequencing of several strains is ongoing. Continuous maintenance of living cultures ensures the preservation of strains, whose majority are cryopreserved (as back-up at -70°C) in order to limit the genetic drift. BCCM/ULC obtained an ISO 9001:2015 certification for public and safe deposits, and distributions of strains, as part of the multi-site certification for the Belgian Coordinated Collections of Microorganisms (BCCM) consortium. The policies of acquisition and distribution of the collection are translated respectively into contracts called Material Accession Agreements (MAA) and Material Transfer Agreements (MTA). This guarantees safe fit-for-use microbiological material and data compliant with the rules on access and utilization of the Nagoya Protocol under the Convention on Biological Diversity (12 October 2014). BCCM/ULC progressively incorporates the most interesting strains from the research collection of the host laboratory into the public collection, whose variety is also enriched by public deposits from other geographical areas (more temperate). The collection is also interested to test new cultivation methods to better reproduce the complex ecological interactions experienced in nature. In addition, Antarctic cyanobacterial strains are known to produce a range of secondary metabolites with different potential bioactivities, as well as the exploration of some unknown gene clusters identified in the first Antarctic cyanobacterial genome ever determined may potentially lead to discover novel peptides which could have biotechnological or biomedical applications. [less ▲]

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See detailCold Adaptation Strategy of the Antarctic Cyanobacterium P. priestleyi ULC007
Durieu, Benoit ULiege; Baurain, Denis ULiege; Wilmotte, Annick ULiege et al

Poster (2018, June 19)

In Antarctica, Cyanobacteria are key primary producers and play a major role in the colonization of deglaciated habitats. Cyanobacterial mats are widespread in aquatic biotopes and often dominate the ... [more ▼]

In Antarctica, Cyanobacteria are key primary producers and play a major role in the colonization of deglaciated habitats. Cyanobacterial mats are widespread in aquatic biotopes and often dominate the total phototrophic biomass. In order to gain further insights on the mechanisms underlying the ecological success of Antarctic cyanobacteria, we studied the gene repertoire of Phormidesmis priestleyiULC007, a filamentous cyanobacterium isolated from shallow freshwater lake microbial mats in the Larsemann Hills. Here, we investigate the occurrence of genes involved in the cold stress response as a proxy to the adaptation to environmental conditions in Antarctica. We compare a selection of 42 PEGs (protein encoding genes) linked to cold adaptation in 72 cyanobacterial genomes. Polar strains have the highest number of copies of genes coding for fructose aldolase, chaperone Hsp, and universal stress protein and a high number of fatty acid desaturase and genes involved in exopolysaccharide (EPS) biosynthesis. To provide a better overview of the genetic mechanisms of adaptation to cold, we investigated the gene functional categories based on the RAST subsystems technology. Polar strains have the most occurrences for subsystems “Choline and Betain Biosynthesis”, “DNA repair”, “EPS biosynthesis” and “Heat shock DnaK gene cluster”. Our results underline the importance of these functions in the adaptation mechanisms of cyanobacteria to the polar environment. [less ▲]

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See detailBiogeography of Cyanobacteria in Antarctic Mats and Implication for Conservation
Durieu, Benoit ULiege; Lara, Yannick ULiege; Stelmach Pessi, Igor et al

Conference (2018, June 19)

On the Antarctic continent, cyanobacterial mats are widespread in the lacustrine biotopes and they often dominate the phototrophic biomass. Their diversity and biogeography are poorly understood because ... [more ▼]

On the Antarctic continent, cyanobacterial mats are widespread in the lacustrine biotopes and they often dominate the phototrophic biomass. Their diversity and biogeography are poorly understood because most studies cover a limited geographic area or are based only on morphotypes. Therefore, cyanobacteria are not fully taken into account in the biological datasets used to delineate conservation biogeographic regions (ACBRs). Recently, we have shown by 454 pyrosequencing of cyanobacteria-specific 16S rRNA amplicons that their distribution across the lacustrine ecosystems could be explained by ecological parameters (e.g. salinity and dissolved organic carbon). In order to further test this hypothesis, we significantly increased the spatial coverage of our samples. Here, we describe the results of 16S rRNA amplicons Illumina sequencing of 98 cyanobacterial mat samples from 10 ACBRs. From the 16012393 raw reads, 713 OTUs were obtained by bioinformatics analysis. Preliminary results show that both ecological parameters and latitude could explain the patterns of cyanobacterial communities. Indeed, nonmetric multidimensional scaling shows that sub-Antarctic samples (Macquarie and Marion Islands) group with North-East Antarctic Peninsula samples, whereas more continental samples (e.g. East Antarctica, South Victoria Land) group together. These findings can form the basis for a better understanding and a more adequate conservation of lacustrine ecosystems in Antarctica. [less ▲]

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See detailEx-situ Conservation of Polar Cyanobacteria in the BCCM/ULC Collection
Wilmotte, Annick ULiege; Beets, Kim; Simons, Véronique et al

Poster (2018, June)

The BCCM/ULC public collection is funded by the Belgian Science Policy Office (BELSPO) and aims to gather a representative portion of Polar cyanobacterial diversity from different ecological origins ... [more ▼]

The BCCM/ULC public collection is funded by the Belgian Science Policy Office (BELSPO) and aims to gather a representative portion of Polar cyanobacterial diversity from different ecological origins (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.) and ensure their ex-situ conservation in a context of global change. These strains are available for researchers to study the biodiversity, taxonomy, evolution, adaptations to harsh environmental conditions, and genomic make-up of Polar cyanobacteria. Currently, there are 120 cyanobacterial strains of Polar origin in the collection (catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). The strains are kept living and their cryopreservation is currently tested. The collection is ISO 9001 certified for depositing and distributing strains, as part of the multi-site certification of the Belgian Coordinated Collections of Microorganisms (BCCM) consortium. Morphological and molecular identification (based on 16S rRNA sequences) indicate that the strains belong to the orders Chroococcales, Chroococcidiopsidales, Nostocales, Oscillatoriales, Pleurocapsales, and Synechococcales. This broad genotypic distribution makes the BCCM/ULC collection particularly interesting for phylogenomic studies. The genomes of several strains are currently being sequenced and the first genome of an Antarctic cyanobacterial strain, Phormidesmis priestleyi ULC007 was recently published. [less ▲]

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See detailKeeping microalgae safe and available
Santoro, Mariano ULiege; Chaerle, Peter; Lara, Yannick ULiege et al

Poster (2018, May)

ULC and DCG public collections of cyanobacteria and diatoms, respectively, are funded by the Belgian Science Policy Office and belong to the consortium of Belgian Co-Ordinated Collections of ... [more ▼]

ULC and DCG public collections of cyanobacteria and diatoms, respectively, are funded by the Belgian Science Policy Office and belong to the consortium of Belgian Co-Ordinated Collections of Microorganisms. They have an ISO9001 certification for the deposits and distributions of strains. BCCM/ULC is one of the largest BRC of documented (sub)polar cyanobacteria. It aims to represent the (sub)polar cyanobacterial diversity from a wide range of different habitats and to promote understanding of cyanobacterial adaptation mechanisms in high latitudes. It comprises 175 cyanobacterial strains (120 of polar origin) belonging to the more representative orders. Public, safe deposits and strains distribution (or genomic DNA) are provided to clients for fundamental and applied research. The first sequenced Antarctic cyanobacterial genome contains protein encoding genes involved in stress response and unknown gene clusters, potentially leading to discover novel secondary metabolites [1], in agreement with previous findings of antimicrobial activity of compounds from Antarctic strains [2]. BCCM/ULC will develop a culturomics approach to isolate target microorganisms. BCCM/DCG is the only BRC specialized in diatoms, the most species-rich group of aquatic photosynthetic organisms in freshwater and marine ecosystems. BCCM/DCG currently holds 514 publicly available strains originating from a wide geographic area and belonging to 48 species (representing all the principal phylogenetic lineages and ecological groups) most of which are cryopreserved. Next to the biological material, there is for the majority of the strains, extra data available: growth temperature, mating system, auxosporulation information, initial and minimal cell size, and sequence data. Additionally, many of the strains/taxa available at BCCM/DCG have been subject of published research focused on diatom genomics, cell and life cycle, determination and comparison of (eco)physiological properties, algae-bacteria interaction, and diatom population genetics, evolution and diversity. [1] Lara et al. (2017) Genome Announc, 5 (e01546-16) [2] Taton et al. (2006) J. Phycology, 42 (1257–1270) [less ▲]

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