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See detailUnravelling the secret of the resistance of desert strains of Chroococcidiopsis to desiccation and radiation
Billi, Daniela; Fagliarone; Verseux, Cyprien et al

in Van de Putte, Anton (Ed.) Book of abstracts: XIIth SCAR Biology Symposium, Leuven, Belgium, 10-14 July 2017. (2017, June)

Chroococcidiopsis is a unicellular cyanobacterial genus that is growing in extreme dry conditions, either in low or high temperatures. At the lower end of the spectrum, they live as cryptoendoliths in ... [more ▼]

Chroococcidiopsis is a unicellular cyanobacterial genus that is growing in extreme dry conditions, either in low or high temperatures. At the lower end of the spectrum, they live as cryptoendoliths in rocks of the Mc Murdo Dry Valleys in Antarctica where they were discovered by Imre Friedmann, while at the higher end, they grow as hypoliths/endoliths in hot deserts, e.g. Negev, Gobi, Atacama. The capacity of desert strains of Chroococcidiopsis to stabilize their sub-cellular organization is so efficient that, when dried, they can cope with simulated space and Martian conditionsas well as with high doses of ionizing and UV radiations . [less ▲]

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See detailA strategy to protect reference sites for future microbiology research in Antarctica
Wilmotte, Annick ULiege; Willems, Anne; Verleyen, Elie et al

in Van de Putte, Anton (Ed.) Book of abstracts: XIIth SCAR Biology Symposium, Leuven, Belgium, 10-14 July 2017. (2017, June)

In addition to iconic animals and birds, Antarctica harbours surprisingly diverse microbial communities that drive important biogeochemical processes in virtually all habitats, including ice-free regions ... [more ▼]

In addition to iconic animals and birds, Antarctica harbours surprisingly diverse microbial communities that drive important biogeochemical processes in virtually all habitats, including ice-free regions, ice sheets and subglacial habitats. Recent studies have shown that Antarctic microbiomes may have unique compositions and functions, exhibit biogeographic patterns, and include endemic taxa that have survived in refugia since the continent started to glaciate. Microbial habitats are under constant pressure due to anthropogenic activities, which may introduce non-indigenous microorganisms, via human bodies, clothing, food, cargo, or construction material. New ‘entry points‘ for microbial contamination are a consequence of the increase and diversification of tourism and research stations. Climatic changes might increase the probability of establishment of non-native taxa. The impacts of such introductions are still unknown, but might lead to a loss of the native microbial biodiversity, or its modification. The technical progress in molecular methodologies has generated very sensitive high-throughput methods. They have the potential to describe the microbial communities with unprecedented detail. However, due to the anthropogenic pressure described above, we may be losing the pristine Antarctic areas that would enable scientists to study the native microbial flora, its functions and properties. One tool of the Protocol on Environmental Protection of the Antarctic Treaty that could be specifically used to protect microbial habitats is the creation of inviolate areas where a special entry permit is required (inside ASPAs, for example) and quarantine equipment needs to be used. These zones could be set aside for future research and become extremely valuable as after a few decades, they would be unique examples of pristine habitats, representative of the native microbial diversity and processes. [less ▲]

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See detailSuccessional Dynamics of Cyanobacterial Communities Following the Retreat of Two Glaciers in Petunia Bay (Svalbard)
Stelmach Pessi, Igor ULiege; Pushkareva, Ekaterina; Lara, Yannick ULiege et al

Conference (2017, April)

Most glaciers in Svalbard (High Arctic) have been retreating and thinning since the end of the Little Ice Age in the late 19th century. As a glacier retreats, it exposes new terrestrial habitats for the ... [more ▼]

Most glaciers in Svalbard (High Arctic) have been retreating and thinning since the end of the Little Ice Age in the late 19th century. As a glacier retreats, it exposes new terrestrial habitats for the colonization by pioneering (micro)organisms. Here we report on the successional trajectories of cyanobacterial communities along a 100-year deglaciation gradient in the Ebba- and Hørbyebreen glacier forefields (Petunia Bay, central Svalbard). Cyanobacterial biomass and community composition were evaluated by epifluorescence microscopy and pyrosequencing of partial 16S rRNA gene sequences. Pseudanabaenales was the most abundant order in both forefields, followed by Chroococcales, Oscillatoriales, Synechococcales, Nostocales and Gloeobacterales. Succession was characterized by a decrease in phylotype richness and a marked turnover in community structure, resulting in a separation between initial (10–20 years since deglaciation), intermediate (30–50 years), and advanced (80–100 years) communities. Community turnover was explained by a combination of temporal and environmental factors, which accounted together for 46.9% of the variation in community structure. Interestingly, phylotypes associated with initial communities were related to potentially novel taxa (i.e. <97.5% similar to sequences currently available on GenBank) and sequences predominantly restricted to polar biotopes, suggesting that the initial colonization is performed by cyanobacteria from glacial and periglacial habitats. Advanced communities, on the other hand, included genotypes with a wider geographic distribution, which are likely able to establish only after the microenvironment has been modified by pioneering taxa. [less ▲]

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See detailDraft genome sequence of the axenic strain Phormidesmis priestleyi ULC007, a cyanobacterium isolated from Lake Bruehwiler (Larsemann Hills, Antarctica)
Lara, Yannick ULiege; Durieu, Benoit ULiege; Cornet, Luc ULiege et al

in Genome Announcements (2017)

Phormidesmis priestleyi ULC007 is an Antarctic freshwater cyanobacte- rium. Its draft genome is 5,684,389 bp long. It contains a total of 5,604 protein- encoding genes, of which 22.2% have no clear ... [more ▼]

Phormidesmis priestleyi ULC007 is an Antarctic freshwater cyanobacte- rium. Its draft genome is 5,684,389 bp long. It contains a total of 5,604 protein- encoding genes, of which 22.2% have no clear homologues in known genomes. To date, this draft genome is the first one ever determined for an axenic cyanobacterium from Antarctica. [less ▲]

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See detailQui vit dans les conditions extrèmes de l'antartique ?
Savaglia, Valentina ULiege; Wilmotte, Annick ULiege

Conference given outside the academic context (2017)

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See detailMetadata compilation for the B-BLOOMS2 dataset: Cyanobacterial bloom monitoring
Lara, Yannick ULiege; De Wever, Aaike; Verniers, Gisèle et al

in Freshwater Metadata Journal (2017), 28

The B-BLOOMS2 dataset resulted from the monitoring of 4 Belgian reference lakes during the bloom seasons in 2007 and 2008. It is composed of 278 sample events for which 17 environmental parameters are ... [more ▼]

The B-BLOOMS2 dataset resulted from the monitoring of 4 Belgian reference lakes during the bloom seasons in 2007 and 2008. It is composed of 278 sample events for which 17 environmental parameters are available, as well as HPLC based pigment analysis, zooplankton counting, proportion of cyanobacterial populations (from genus to species), and MC-LR concentrations determined by ELISA. Molecular data acquired during this project are also available (http://hdl.handle.net/2268/213145). These data were acquired with the financial support of BELSPO in the frame of the Science for a Sustainable Development programme funding the project B-BLOOMS2 (SD/TE/01). The final report is available at: http://www.bblooms.be/BBLOOMS2_FinalReport.pdf [less ▲]

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See detailMolecular dataset from BELSPO project B-BLOOMS 2
Lara, Yannick ULiege; Wilmotte, Annick ULiege

Report (2017)

This entry is dedicated to answer the need of a link between molecular data, environmental parameters, and counting depositions in the field of microbial ecology. Indeed, it is necessary to implement a ... [more ▼]

This entry is dedicated to answer the need of a link between molecular data, environmental parameters, and counting depositions in the field of microbial ecology. Indeed, it is necessary to implement a new approach to link data that are deposited in GBIF with molecular data set that are deposited on GenBank or that stay in lab computers. In the frame of the BRAIN BELSPO project SAFRED, we attempt to achieve this goal by supplying a sequence template set as designed by the Microbial Antarctic Resource System (mARS). For the B-BLOOMS 2 molecular data set, we also supply a fasta file which contains curated sequences obtained by the DGGE method. These sequences are not published elsewhere. In addition, we added a sequence list which contains Event ID information for each sequences. [less ▲]

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See detailBiogeographic patterns and genomic adaptation of benthic cyanobacteria in Antarctic lakes
Durieu, Benoit ULiege; Stelmach Pessi, Igor ULiege; Lara, Yannick ULiege et al

in XIIth SCAR Biology Symposium, Leuveun, 10-14 July 2017 (2017)

Detailed reference viewed: 44 (15 ULiège)
See detailThe BCCM/ULC collection to conserve the biodiversity and study the secondary metabolites of Polar cyanobacteria
Lara, Yannick ULiege; Durieu, Benoit ULiege; Renard, Marine ULiege et al

Poster (2016, November 16)

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

In the Polar Regions, Cyanobacteria are the key primary producers and main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic microbial mats in lakes and soil crusts. Their success in these harsh cold conditions can probably be explained by particular adaptations to survive freeze/thaw cycles, seasonally contrasted light intensities, high UV radiations, dessication and other environmental stresses. The BCCM/ULC public collection is funded by the Belgian Science Policy Office since 2011. It has obtained the ISO9001 certification for deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. This collection aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic mats, soil crusts, cryoconites, endoliths,….) and make it available for researchers to study the taxonomy, evolution, adaptations to harsh environmental conditions, pigments, and genomic make-up. It presently includes 226 cyanobacterial strains, of which 119 are of Antarctic origin (catalogue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). As shown by morphological identification, the strains belong to five orders (Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales). The 16S rRNA and ITS sequences of the strains are being characterized. The first 85 Antarctic strains already studied are distributed into 25 Operational Taxonomic Units (OTUs = groups of sequences with > 97,5% 16S rRNA similarity), and thus, represent a quite large diversity. Moreover, strains identified as members of the genera Leptolyngbya or Phormidium appear in several lineages. This supports the idea that there is a need to revise the taxonomy of these polyphyletic genera with a simple filamentous morphology. To better understand the functioning, metabolism and adaptative strategies of cyanobacteria in the extreme Antarctic environment, the genome sequencing of 11 strains has been started. Pair-read data from illumina MiSeq runs were obtained and submitted to a bioinformatic pipeline dedicated to the assembly of genomes and search of sequences involved in the biosynthesis of secondary metabolites. Gene cluster prediction analysis allowed to characterize 20 clusters of NRPS, PKS and hybrid NRPS-PKS from 2 to 66kb. Surprisingly, none of the characterized operons had previously been described in the literature. [less ▲]

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See detailThe ‘cyanobiome’ of Svalbard, High Arctic
Stelmach Pessi, Igor ULiege; Laughinghouse, H Dail; Velazquez, David et al

Poster (2016, October 28)

Over the last decades, the Arctic has experienced a warming trend that is nearly twice as high as the global average, a phenomenon known as ‘Arctic amplification’. The impact of warmer temperatures on ... [more ▼]

Over the last decades, the Arctic has experienced a warming trend that is nearly twice as high as the global average, a phenomenon known as ‘Arctic amplification’. The impact of warmer temperatures on Arctic ecosystems is still unclear. Cyanobacteria are the key primary producers in freshwater and terrestrial Arctic ecosystems, where they are the driver for numerous ecological functions. For a better understanding of the impacts of climate change on Arctic ecosystems, baseline knowledge on cyanobacterial diversity and distribution is crucial. Here we investigate, for the first time, the biogeographic patterns of cyanobacterial communities across Svalbard, using 454 pyrosequencing of partial 16S rRNA gene sequences. Samples were taken from distinct ecosystems and biogeographic zones. We also compare the studied communities with similar Antarctic communities. [less ▲]

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See detailThe BCCM/ULC collection to conserve the biodiversity and explore the applied potential of Polar cyanobacteria
Becker, Pierre; SZTERNFELD, P; ANDJELKOVIC, M et al

Poster (2016, October 28)

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. For example, they build benthic microbial ... [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. For example, 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 226 cyanobacterial strains, with 119 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 being characterized. Our results show that the Antarctic strains are positioned into 25 OTUs (sequences with > 97,5% 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. Among these bioactive metabolites, some display antibiotic, anticancer or antifungal effects. In collaboration with the BCCM/IHEM collection of biomedical fungi, a screening of cyanobacterial strains from BCCM/ULC was performed in order to discover potential new antifungal drugs. The analysis of a first set of methanol extracts from 15 different strains put in evidence the antifungal activity of a Phormidium priestleyi isolate. The latter remains active up to 0.5% (v/v) of fungal culture and was able to inhibit the growth of various fungal species among Candida, Cryptococcus, Aspergillus, and Penicillium. The raw extract was subjected to HPLC and a fraction containing the active molecule was obtained. This molecule appeared to be a thermostable hydrophobic compound. Moreover, in vitro toxicological analyses suggest that the compound has a general cytotoxic effect that could be inhibited by the mammalian metabolism. Further analyses are needed to identify the molecule and to determine if it could be a candidate for a new antifungal drug. 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 detailWhy a culture collection of Cyanobacteria?
Wilmotte, Annick ULiege; Renard, Marine ULiege; Simons, Véronique

Poster (2016, September 08)

The BCCM/ULC public collection is funded by the Belgian Science Policy Office since 2011 and an ISO9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi ... [more ▼]

The BCCM/ULC public collection is funded by the Belgian Science Policy Office since 2011 and an ISO9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. The collection aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic mats, soil crusts, cryoconites, endoliths…) and make it available for researchers to study the taxonomy, evolution, adaptations to harsh environmental conditions, and genomic make-up. It presently includes 226 cyanobacterial strains, with 120 being of (Sub) Antarctic origin (http://bccm.belspo.be/catalogues/ulc-catalogue-search). The morphological identification shows that the strains belong to the orders of Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. Continuous maintenance of living cultures, some of which are also cryopreserved, ensure the preservation and the possibility to rapidly deliver strains to clients for fundamental and applied research. [less ▲]

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See detailCyanobacterial Diversity In Antarctic Aquatic Microbial Mats
Stelmach Pessi, Igor ULiege; Lara, Yannick ULiege; Durieu, Benoit ULiege et al

Poster (2016, September 08)

Detailed reference viewed: 11 (5 ULiège)
Peer Reviewed
See detailSuccessional trajectories of cyanobacterial communities following glacier retreat in Svalbard (High Arctic)
Stelmach Pessi, Igor ULiege; Pushkareva, Ekaterina; Borderie, Fabien ULiege et al

Conference (2016, September 01)

The effects of global warming are pronounced at high northern latitudes, where the warming trend observed for the past decades is almost twice as the global average. Most glaciers in Svalbard (High Arctic ... [more ▼]

The effects of global warming are pronounced at high northern latitudes, where the warming trend observed for the past decades is almost twice as the global average. Most glaciers in Svalbard (High Arctic) have been retreating and thinning since the end of the Little Ice Age in the late 19th century, and retreat rates have increased substantially in the last decades. As a glacier retreats, it systematically exposes new terrestrial habitats for the colonization by pioneering (micro)organisms. Distance from the glacier terminus can be used as a proxy for time since deglaciation, which makes glacier forefields well suited for the study of primary succession. In the present study, we investigated the successional trajectories of cyanobacterial communities along a 100-year deglaciation gradient in the forefield of two Svalbard glaciers (Ebba- and Hørbyebreen). Cyanobacterial abundance was assessed by epifluorescence microscopy and cyanobacterial diversity was investigated by pyrosequencing of partial 16S rRNA gene sequences. Filamentous cyanobacteria were more abundant than unicellular and heterocystous cyanobacteria in both forefields, and an increase in the abundance of cyanobacteria was observed along the deglaciation gradients. Pseudanabaenales was the most OTU-rich order, followed by Chroococcales, Oscillatoriales, Synechococcales, Nostocales and Gloeobacterales. At the genus level, classified phylotypes were assigned to Leptolyngbya, Phormidium, Nostoc, Pseudanabaena, Chroococcidiopsis and Microcoleus. Interestingly, OTU richness increased along the deglaciation gradient in Ebbabreen, but an inverse correlation was observed in Hørbyebreen. Beta diversity estimations indicated contrasting cyanobacterial phylogenetic structures along the temporal gradient, with a clear separation of initial (10-20 years), intermediate (30-50) and advanced (80-100) communities. Time since deglaciation accounted for around 25% of the phylogenetic variability in both forefields, with organic carbon content also explaining a significant proportion of community turnover along the deglaciation gradients. Taxonomic composition was somewhat constant along the deglaciation gradient, but OTUs associated with initial communities were related to sequences predominantely restricted to polar biotopes, while advanced communities included phylotypes related to cosmopolitan taxa. [less ▲]

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See detailThe BCCM/ULC collection to conserve and study the biodiversity of Polar cyanobacteria
Wilmotte, Annick ULiege; Renard, Marine ULiege; Lara, Yannick ULiege et al

Poster (2016, September)

The BCCM/ULC public collection of Cyanobacteria has been funded since 2011 by the Belgian Science Policy Office. BCCM/ULC is currently holding 226 cyanobacterial strains, with 119 being of Antarctic ... [more ▼]

The BCCM/ULC public collection of Cyanobacteria has been funded since 2011 by the Belgian Science Policy Office. BCCM/ULC is currently holding 226 cyanobacterial strains, with 119 being of Antarctic origin (including 3 from the sub-Antarctic). The cyanobacteria constitute the bacterial phylum with the largest morphological diversity and their taxonomy is still a work in progress. In Polar Regions, Cyanobacteria represent key primary producers and are important drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build extensive benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They have adapted to their environment, and may present interesting features to survive freeze/thaw cycles, seasonally contrasted light intensities, high UV radiations, dessication and other stresses. In this poster, we present the results of the 16S rRNA phylogenetic analysis for 76 Antarctic strains. This allows us to illustrate the diversity present in the collection, to detect lineages for which no genome has yet been sequenced, and to pinpoint taxonomic problems that should be addressed in a more comprehensive study. [less ▲]

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See detail) Inviolate areas to protect reference sites for future microbiology research in Antarctica
Wilmotte, Annick ULiege; Willems, Anne; Verleyen, Elie et al

Conference (2016, August 22)

Antarctica is a continent dominated by microbes. A surprisingly large biodiversity of well-adapted microorganisms live permanently in a variety of habitats, ranging from ice-free to permanently frozen ... [more ▼]

Antarctica is a continent dominated by microbes. A surprisingly large biodiversity of well-adapted microorganisms live permanently in a variety of habitats, ranging from ice-free to permanently frozen areas. Recent studies revealed that some microbial groups exhibit biogeographic patterns, include endemic taxa and have survived in refugia since the formation of the continental ice sheet. Microbial habitats are under constant pressure due to anthropogenic activities which may introduce non-indigenous microorganisms, via bodies, clothing, cargo and food. New ‘entry points‘ for microbial contamination are a consequence of the increase and diversification of tourism and research stations. Climatic changes might furthermore increase the probability of the successful establishment of populations of non-native taxa. The impacts of such introductions are still unknown, and might lead to a loss of the native microbial biodiversity, or its modification, which in turn might affect ecosystem functioning. The recent technical progress in molecular methodologies have generated very sensitive high-throughput analyses and have the potential to describe microbial communities with unprecedented detail. However, we may be losing the pristine Antarctic areas that would enable scientists to study the native microbial flora, its functions and properties. The Protocol on Environmental Protection of the Antarctic Treaty foresees the designation of Antarctic Specially Protected Areas (ASPA) to protect “outstanding environmental, scientific, historic, aesthetic, or wilderness values, any combination of those values, or on-going or planned scientific research” (http://www.ats.aq/e/ep_protected.htm). However, the designation of ASPAs has not followed a systematic planning, and often focused on the conservation of large mammals, birds and/or vegetation and other iconic species. Microorganisms have the handicap of generally being invisible without a microscope and relevant expertise, and require molecular methods for species delineation. Terrestrial habitats are protected in 55 out of the 72 existing ASPAs (in total less than 700 km2). Microalgae are protected in 16 ASPAs, cyanobacteria in 7 and snow microalgae in 3. Only 8 ASPAs mention ‘Microbial habitats’, ‘microbial communities’ or ‘soil and lake microflora’. One tool of the Protocol that could be specifically used to protect microbial habitats is the creation of inviolate areas where a special entry permit is required (inside ASPAs, for example), and quarantine equipment should be worn. These zones could be set aside for future research and after a few decades, they would be unique examples of truly pristine habitats, and representative of the native microbial diversity. Examples of this are ASPA 126, Byers Peninsula, and ASPA 172, Lower Taylor Glacier and Blood Falls. Such an option would require discussions and a consensus among scientists of other disciplines than microbiology to select these regions, and develop careful management protocols of the sites and their vicinity. In addition, gaps in our knowledge should be addressed, like the extent of transportation of microorganisms by natural means (winds, birds...), and the probability of subsequent colonization of new areas by microorganisms coming from other Antarctic regions or from outside Antarctica. Let’s hope that the dialogue between scientists and policy makers will improve the conservation of Antarctic microbial diversity and safeguard the possibility to study these unique communities in the future by the next generation of scientists, with the most advanced techniques of the time. [less ▲]

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See detailCharacterization of Leptolyngbya and Phormidium diversity in Antarctic biotopes
Lara, Yannick ULiege; Durieu, Benoit ULiege; Borderie, Fabien et al

Poster (2016, August)

Thin filamentous cyanobacteria identified by morphology as Leptolyngbya and Phormidium are common in Antarctic biotopes, ranging from microbial mats in lakes and seepages to terrestrial biofilms and ... [more ▼]

Thin filamentous cyanobacteria identified by morphology as Leptolyngbya and Phormidium are common in Antarctic biotopes, ranging from microbial mats in lakes and seepages to terrestrial biofilms and crusts. Due to their morphological simplicity, a large number of species were described but the genetic basis of these taxa is largely unknown. The litterature shows that these genera are polyphyletic and that they need detailled revisions.The isolation of strains in unialgal cultures is the first step of an asssessment of the real diversity of these genera. Here we describe the molecular analysis of Antarctic Leptolyngbya antarctica, L. cf fragilis, L. glacialis and Phormidium priestleyi using sequences of different taxonomic markers, the 16S rRNA gene, the ITS and the rpoC1 gene. They appear distributed into four lineages. The phylogenetic tree supports the transfer of certain Phormidium priestleyi strains to the genus Phormidesmis. Similarly, some L. antarctica clearly belong to the new genus Nodosilinea. [less ▲]

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See detailThe BCCM/ULC collection: a Biological Ressource Center to give access to the Antarctic cyanobacterial diversity
Wilmotte, Annick ULiege; Renard, Marine ULiege; Lara, Yannick ULiege et al

Poster (2016, August)

On the Antarctic continent, Cyanobacteria represent the key primary producers and the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic ... [more ▼]

On the Antarctic continent, Cyanobacteria represent the key primary producers and the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They may present interesting features to survive freeze/thaw cycles, sea-sonally 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 microbial mats, soil crusts, cryoconites, endoliths, etc.). It makes it available for researchers to study the taxonomy, evolu-tion, adaptations to harsh environmental conditions, and genomic make-up. It pres-ently includes 226 cyanobacterial strains, with 119 being of Antarctic origin (cata-logue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). The morphological identification shows that the strains belong to the orders Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. We present here the molecular datasets showing the diversity of the BCCM/ULC strains, studied on the basis of the 16S rRNA gene. A selection of strains was also characterized by sequencing of rpoC1, recA, and gyrA genes after amplification with newly designed primers. Our results mainly show that 25 OTUs included strains of Antarctic origin. Moreo-ver, strains identified as members of the genera Leptolyngbya or Phormidium ap-pear in several lineages. This supports the need to revise these polyphyletic genera with a simple filamentous morphology. A certain divergence of some Antarctic strains from related strains isolated from other regions can also be observed. It suggests that a portion of the Antarctic cyanobacterial flora may have evolved in-dependently from the cyanobacteria in other continents. [less ▲]

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See detailMicroalgae diversity along an Antarctic glacier forefield
Stelmach Pessi, Igor ULiege; Rybalka, Natalia; Friedl, Thomas et al

Poster (2016, August)

Glacier retreat due to global warming has been observed in all the cryosphere [1], systematically exposing new terrestrial ecosystems that had previously been covered by ice. Primary succession, i.e. the ... [more ▼]

Glacier retreat due to global warming has been observed in all the cryosphere [1], systematically exposing new terrestrial ecosystems that had previously been covered by ice. Primary succession, i.e. the assembly of biological communities on newly exposed habitats and their change over time, can be studied along glacier forefields, where distance from the glacier terminus is used as a proxy for time since deglaciation [2]. The study of microbial succession is still at its infancy, but understanding the relationships between microbial communities and soil development will provide us with crucial knowledge on how they influence and respond to changes in environmental conditions. Here, we investigated the structure of microalgal communities along a deglaciation gradient in the forefield of Collins Glacier (Fildes Peninsula, King George Island, Maritime Antarctica). [less ▲]

Detailed reference viewed: 50 (3 ULiège)
See detailDiversity and distribution of microorganisms in microbial mats of Antarctic lakes
Lara, Yannick ULiege; Durieu, Benoit ULiege; Stelmach Pessi, Igor ULiege et al

Conference (2016, August)

The BelSPO project CCAMBIO aims to study the biogeographical distribution of microorganisms in lacustrine microbial mats using a combination of techniques including microscopic observations, strain ... [more ▼]

The BelSPO project CCAMBIO aims to study the biogeographical distribution of microorganisms in lacustrine microbial mats using a combination of techniques including microscopic observations, strain isolation and genetic characterisation, and molecular diversity assessments using Next Generation Sequencing of environmental DNA. The samples were collected in different Antarctic and sub-Antarctic biogeographical regions. Preliminary multivariate analysis of >130 samples revealed strong bioregionalisation patterns in microbial eukaryotes, which are in agreement with the classical subdivision of the Antarctic Realm into Maritime Antarctica, Continental Antarctica and the Sub-Antarctic Islands generally observed in plants and animals. The biogeographic structuring was less strong between the continent and Maritime Antarctica in prokaryotes suggesting more regular dispersal events between these two regions. The Sub-Antarctic assemblages harboured more complex foodwebs, with arthropods, nematods, rotifers, flatworms and annelids as main metazoan groups. Lakes on the continent, however, were characterised by fewer metazoan groups and a greater importance of microbial herbivores and secondary consumers, including a relative high diversity of ciliates and tardigrades. In a first analysis of microbial mats from five Antarctic lakes and an aquatic biofilm from the Sub-Antarctic, the majority of the cyanobacterial OTUs retrieved were related to filamentous taxa such as Leptolyngbya and Phormidium, which are common genera in Antarctic lacustrine microbial mats. However, other phylotypes related to different taxa such as Geitlerinema, Pseudanabaena, Synechococcus, Chamaesiphon, Calothrix and Coleodesmium were also found. Results revealed a much higher diversity than what had been reported using traditional methods and also highlighted remarkable differences between the cyanobacterial communities of the studied lakes. In the coming months, the molecular diversity data will be deposited into the “Microbial Antarctic Resource System (MARS)” presently developed into the webportal ‘biodiversity.aq’. Better knowledge of the diversity and distribution of microorganisms will contribute to a better assessment of their resilience and local/regional responses to global change [less ▲]

Detailed reference viewed: 64 (8 ULiège)