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See detailPolyphasic characterization of 10 selected ecologically relevant filamentous cyanobacterial strains from the South Shetland Islands, Maritime Antarctica
Jancusova, Miroslava; Kovacik, Lubomir; Pereira, Antonio Batista et al

in FEMS Microbiology Ecology (in press)

The evolutionary relationships of 10 Antarctic cyanobacterial strains of the order Oscillatoriales isolated from King George and Deception Islands, South Shetland Islands were studied by a polyphasic ... [more ▼]

The evolutionary relationships of 10 Antarctic cyanobacterial strains of the order Oscillatoriales isolated from King George and Deception Islands, South Shetland Islands were studied by a polyphasic approach (morphology, 16S rRNA and internal transcribed spacer sequences). The studied taxa are characteristic of coastal Antarctic biotopes, where they form distinct populations and ecologically delimited communities. They were isolated from terrestrial habitats: microbial mats in seepages; crusts on soil, rocks, bones and mosses; mud, sometimes close to bird colonies; and from guano. Based on major phenotypic features, the strains were divided into four distinct morphotypes: Leptolyngbya borchgrevinkii (A), Leptolyngbya frigida (B), Microcoleus sp. (C) and Wilmottia murrayi (D). This morphological identification was in agreement with the phylogenetic relationships. For the first time, the 16S rRNA gene sequence of a strain corresponding to the L. borchgrevinkii morphotype was determined. Morphotype B is most related to sequences assigned to L. frigida isolated from microbial mats of coastal lakes in East Antarctica. Morphotype C belongs to a cluster including strains with morphotypes corresponding to Microcoleus attenuatus, Microcoleus favosus and Microcoleus sp., which are from Antarctica and other continents. Morphotype D is grouped with sequences assigned to W. murrayi mostly isolated from Antarctica. [less ▲]

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See detailThe CCAMBIO project to characterize the biodiversity and distribution of microorganisms in microbial mats of Antarctic lakes
Durieu, Benoit ULg; Lara, Yannick ULg; Obbels, Dagmar et al

Poster (2016, April 29)

The BelSPO project CCAMBIO aims to study the biogeographical distribution of microorganisms in lacustrine microbial mats using a combination of techniques including microscopical observations (light and ... [more ▼]

The BelSPO project CCAMBIO aims to study the biogeographical distribution of microorganisms in lacustrine microbial mats using a combination of techniques including microscopical observations (light and electronic microscopy), strain isolation, and molecular diversity assessment using Next Generation Sequencing. The samples were collected in different Antarctic and sub-Antarctic biogeographical regions. A detailed microscopic study of the Antarctic diatom diversity allowed to revise a number of taxa and discover new ones. A multivariate analysis of diatoms showed that these regions hosted different diatom flora. Endemic diatom taxa were also observed, and a multigene molecular phylogeny of Pinnularia borealis showed a high genetic diversity. Pilot studies were conducted for the microeukaryotes and cyanobacteria to select NGS protocols and bioinformatic pipelines. Preliminary multivariate analysis of over 100 samples revealed that distinct biogeographic zones could be recognized in both the prokaryote and eukaryote data, which is 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. Moreover, Sub-Antarctic assemblages harboured more complex foodwebs, with quite diverse 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. Variation partitioning analysis revealed that spatial variables that approximated large-scale regional contrasts in historical (e.g. deglaciation history, geological origin) and climatic factors (e.g. mean annual air temperature) significantly explained the largest portion of the observed variation in community structure for eukaryotes, while in the prokaryote data environmental gradients related to conductivity were more important. 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 higher diversity than what had been reported using traditional methods based on microscopic observations and cultivation and also highlighted remarkable differences between the cyanobacterial communities of the studied lakes. In the next months, the molecular diversity data will be deposited into the “Microbial Antarctic Resource System (MARS)” presently developed into the webportal ‘biodiversity.aq’. The 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 ▲]

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See detailElucidating diversity of thin filamentous mat-forming Antarctic cyanobacteria
Lara, Yannick ULg; Durieu, Benoit ULg; Deblander, Victor ULg et al

Poster (2016, April 29)

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

Freshwater ecosystems range from glacial cryoecosystems, 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 matrices that shelter other organisms, and carry out the primary production. Narrow filamentous cyanobacteria belonging to the genera Leptolyngbya and Phormidium are especially abundant in Antarctic microbial mats and are essential for the formation of matrix. However, the lack of morphological criteria and the small cell size of cyanobacteria belonging to these two genera make their identification problematic. Indeed, they are known as polyphyletic taxa according to botanical and bacteriological criteria. The characterization of strains is the first step for an assessment of the real diversity and for understanding their role in the environment. We designed a polyphasic approach that combines molecular analyses, environmental physiology experiments and microscopic observations. Briefly, we amplified and sequenced three loci (16S rRNA, ITS, and rpoC1) for 31 strains of Leptolyngbya and Phormidium. We performed whole genome sequencing for five strains. Cultures at different stage were observed by light and epifluorescence microscopy. Finally, selected strains were grown in nitrogen-limited. The Leptolyngbya and Phormidium strains were distributed into four lineages. Phylogenetic trees supported the distribution of P. priestleyi strains into at least two potentially new lineages, and L. antarctica strains were separated into one endemic and one cosmopolitan lineage. This was supported by the microscopic observations of 1-year old cultures. Genome analyses revealed the presence of sequences related to the production of secondary metabolites in strains from two of the studied lineages. Secondary metabolites are often known for their antimicrobial activities. Such properties would partly explain how cyanobacterial mats survive to predation and degradation by other bacteria. This work provides the first building block to the understanding of survival strategies developed by mat-forming cyanobacteria and how they succeeded as the most abundant phototrophs on the Antarctic continent. This work was realized in the frame of the BelSPo project CCAMBIO. [less ▲]

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See detailON THE USE OF HIGH-THROUGHPUT SEQUENCING FOR THE STUDY OF CYANOBACTERIAL DIVERSITY IN ANTARCTIC AQUATIC MATS 1
Stelmach Pessi, Igor ULg; De Carvalho Maalouf, Pedro; Laughinghouse, Haywood Dail et al

in Journal of Phycology (2016), 52

The study of Antarctic cyanobacterial diversity has been mostly limited to morphological identification and traditional molecular techniques. High-throughput sequencing (HTS) allows a much better ... [more ▼]

The study of Antarctic cyanobacterial diversity has been mostly limited to morphological identification and traditional molecular techniques. High-throughput sequencing (HTS) allows a much better understanding of microbial distribution in the environment, but its application is hampered by several methodological and analytical challenges. In this work we explored the use of HTS as a tool for the study of cyanobacterial diversity in Antarctic aquatic mats. Our results highlight the importance of using artificial communities to validate the parameters of the bioinformatics procedure used to analyse natural communities, since pipeline-dependent biases had a strong effect on the observed community structures. Analysis of microbial mats from five Antarctic lakes and an aquatic biofilm from the Sub-Antarctic showed that HTS is a valuable tool for the assessment of cyanobacterial diversity. The majority of the 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 and 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. The aquatic biofilm from the Sub-Antarctic had a distinct cyanobacterial community in comparison to the studied Antarctic lakes, which, in turn, displayed a salinity-dependent community-structure at the phylotype level. [less ▲]

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See detailIdentifying the factors determining blooms of cyanobacteria in a set of shallow lakes
Descy, Jean-Pierre; Leprieur, Fabien; Pirlot, Samuel et al

in Ecological Informatics (2016), 34

There is a strong interest in developing a capacity to predict the occurrence of cyanobacteria blooms in lakes and to identify the measures to be taken to reduce water quality problems associated with the ... [more ▼]

There is a strong interest in developing a capacity to predict the occurrence of cyanobacteria blooms in lakes and to identify the measures to be taken to reduce water quality problems associated with the occurrence of potentially harmful taxa. Here we conducted a weekly to bi-weekly monitoring program on five shallow eutrophic lakes during two years, with the aim of gathering data on total cyanobacterial abundance, as estimated from marker pigments determined by HPLC analysis of phytoplankton extracts. We also determined bloom composition and measured weather and limnological variables. The most frequently identified taxa were Aphanizomenon flos-aquae, Microcystis aeruginosa, Planktothrix agardhii and Anabaena spp. We used the data base composed of a total of 306 observations and an adaptive regression trees method, the boosted regression tree (BRT), to develop predictive models of bloom occurrence and composition, based on environmental conditions. Data processing with BRT enabled the design of satisfactory prediction models of cyanobacterial abundance and of the occurrence of the main taxa. Phosphorus (total and soluble reactive phosphate), dissolved inorganic nitrogen, epilimnion temperature, photoperiod and euphotic depth were among the best predictive variables, contributing for at least 10 % in the models, and their relative contribution varied in accordance with the ecological traits of the taxa considered. Meteorological factors (wind, rainfall, surface irradiance) had a significant role in species selection. Such results may contribute to designing measures for bloom management in shallow lakes. [less ▲]

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See detailAerobiology over Antarctica – a new initiative for atmospheric ecology
Pearce, David; Alekhina, Irina; Terauds et al

in Frontiers in Microbiology (2016), 7

The role of aerial dispersal in shaping patterns of biodiversity remains poorly understood, mainly due to a lack of coordinated efforts in gathering data at appropriate temporal and spatial scales. It has ... [more ▼]

The role of aerial dispersal in shaping patterns of biodiversity remains poorly understood, mainly due to a lack of coordinated efforts in gathering data at appropriate temporal and spatial scales. It has been long known that the rate of dispersal to an ecosystem can significantly influence ecosystem dynamics, and that aerial transport has been identified as an important source of biological input to remote locations. With the considerable effort devoted in recent decades to understanding atmospheric circulation in the south-polar region, a unique opportunity has emerged to investigate the atmospheric ecology of Antarctica, from regional to continental scales. This concept note identifies key questions in Antarctic microbial biogeography and the need for standardized sampling and analysis protocols to address such questions. A consortium of polar aerobiologists is established to bring together researchers with a common interest in the airborne dispersion of microbes and other propagules in the Antarctic, with opportunities for comparative studies in the Arctic. [less ▲]

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See detailANNUAL SCIENTIFIC REPORT - Climate change and Antarctic microbial biodiversity (CCAMBIO)
Tytgat, Bjorn; Willems, Anne; Sweetlove, Maxime et al

Report (2015)

Detailed reference viewed: 33 (8 ULg)
See detailDynamic responses of cyanobacterial communities following glacier retreat in the High Arctic (Svalbard)
Stelmach Pessi, Igor ULg; Pushkareva, Ekaterina; Elster, Josef et al

Scientific conference (2015, December)

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See detailA plea for the creation for inviolate areas to protect reference areas for future microbiology research in Antarctica
Wilmotte, Annick ULg; Willems, Anne; Verleyen, Elie et al

Poster (2015, September 08)

Antarctica is essentially a microbial continent. A surprisingly large biodiversity of adapted microorganisms lives permanently in various biotopes of the ice-free areas (about 44,000 km2). Based on ... [more ▼]

Antarctica is essentially a microbial continent. A surprisingly large biodiversity of adapted microorganisms lives permanently in various biotopes of the ice-free areas (about 44,000 km2). Based on molecular methods and microscopic observations, important findings like the presence of potentially endemic taxa, their survival in glacial refugia since the continent moved away from Australia and South America, and the determination of biogeographic patterns have been inferred. Moreover, Antarctic microorganisms may contain novel molecules with potentially pharmaceutical or biotechnological interest. However, microbial habitats are under pressure as a result of nthropogenic introductions. Indeed, as a consequence of human presence, non-indigenous microorganisms are released from bodies, clothing, cargo and food into the environment (Cowan et al. 2011). The increase of tourism and its diversification from coastal cruises to adventurous expeditions into the continent, as well as the increase of research stations and associated impacts, constantly create new ‘entry points‘ for microbial contamination (Chown et al. 2012). The impacts of such introductions are still unknown, and might lead to a loss of the native microbial biodiversity, or its modification by lateral gene transfer. The technical progresses in molecular methodologies, like we currently see with Next Generation Sequencing (NGS), mean that very sensitive high-throughput analyses will become increasingly accessible. They have the potential to describe the microbial communities with unprecedented details without preconceived expectations. However, by that time, we might have lost the pristine Antarctic areas that would enable the scientists to study the native microbial flora, its functioning 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 animals or higher plant communities. Microorganisms have the handicap of generally being invisible without a microscope and relevant expertise, and needing molecular methods to determine their identity. Terrestrial habitats are protected in 55 out of the 72 existing ASPAs (in total less than 700 km2), mostly based on the need to protect vascular plants and bryophyte communities (Shaw et al. 2014). In 28 ASPAs, the protection targets the lichens, whereas 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 no visitation is permitted (inside ASPAs, for example). These zones could be set aside for future research (Hughes et al. 2013) and become extremely valuable. After a few decades, they would be unique examples of truly pristine habitats, representative of the native microbial diversity and processes. Such an option would necessitate discussions and consensus with scientists of other disciplines to select these regions, and careful management protocols of the sites and their vicinity (Hughes et al. 2015). In addition, gaps in knowledge should be addressed, like the extent of transportation of microorganisms by natural means (winds, birds...) (e.g. Pearce et al. 2009), 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 enable to improve the conservation of Antarctic microbial diversity and safeguard the possibility to study these unique communities in the future with the most advanced techniques of the time. The outcome of these discussions might also be of interest for Arctic and alpine regions. [less ▲]

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See detailCHARACTERIZATION OF TEN STRAINS OF FILAMENTOUS CYANOBACTERIA FROM THE SOUTH SHETLAND ISLANDS, MARITIME ANTARCTICA
Kovacik, Lubomir; Pereira, Antonio; Dusinsky, Roman et al

Poster (2015, September 07)

The evolutionary relationships of ten Antarctic cyanobacterial strains of the order Oscillatoriales isolated from King George Island and Deception Island, South Shetland Islands were studied by a ... [more ▼]

The evolutionary relationships of ten Antarctic cyanobacterial strains of the order Oscillatoriales isolated from King George Island and Deception Island, South Shetland Islands were studied by a polyphasic approach. Phenotypic observations of the morphological features and genotypic analyses (16S rRNA and ITS sequences) were performed. Based on major phenotypic features, the strains were divided into four distinct morphotypes: Leptolyngbya borchgrevinkii (A), Leptolyngbya frigida (B), Phormidium autumnale (C) and Wilmottia murrayi (D). This morphological identification was in global agreement with the evolutionary relationships. According to the phylogenetic analysis, the ten strains were divided into two major clades, containing related strain sequences with Leptolyngbya morphotypes in one clade and with morphotypes corresponding to Phormidium, Wilmottia and Microcoleus spp. in the other clade. Each major clade was divided into two sub-clades. For the first time, the 16S rRNA gene sequence of a strain corresponding to the Leptolyngbya borchgrevinkii morphotype (A) was determined, on the basis of strain KOVACIK-ANT 1990/4. The closest sequence to our morphotype A is the clone Fr252 isolated from microbial mat of Antarctic Lake Fryxell. Morphotype B is closest to sequences assigned to Leptolyngbya frigida isolated from microbial mats of lakes in continental East Antarctica. Morphotype C belongs to a cluster including strains with morphotypes corresponding to Phormidium autumnale from Antarctica, but also from Europe. Morphotype D is grouped with sequences of the morphotype assigned to Wilmottia murrayi isolated from Antarctica. [less ▲]

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See detailBEDROCK AND BIOTIC INFLUENCE ON COMMUNITY COMPOSITION IN SOILS FROM THE SØR RONDANE MOUNTAINS, EAST ANTARCTICA
Tytgat, Bjorn; Verleyen, Elie; D'hondt, Sofie et al

Poster (2015, September 07)

Antarctica is a continent of extremes; the low availability of liquid water and nutrients, extreme low temperatures and seasonally variable levels of solar radiation exert high selective pressures on ... [more ▼]

Antarctica is a continent of extremes; the low availability of liquid water and nutrients, extreme low temperatures and seasonally variable levels of solar radiation exert high selective pressures on organisms. Consequently, most life forms in the scarce ice-free regions which represent less than 1% of the surface area of the continent are microbial. Despite this, terrestrial microbial communities are poorly studied and the existing data are geographically focused on McMurdo dry valleys and volcanically active regions. Nunataks, mountain tops protruding through the ice sheets, occur along much of the East Antarctic coast and in the Transantarctic Mountains. Among them, several remained ice-free during Neogene and Pleistocene ice ages and thus may have acted as important refugia for terrestrial life. Here we present the results of a broad-scale survey of microbial biodiversity of ice-free regions in the western Sør Rondane Mountains (Dronning Maud Land (DML), East Antarctica). A total of 66 samples from eight different ice-free regions were selected to represent gradients in bedrock type (gneiss or granite), the macrobiotic content (presence or absence of moss, lichen and/or arthropods) and geographic location. All samples were subjected to both genetic fingerprinting (ARISA) and second generation sequencing (Illumina MiSeq 300PE) targeting the V1 -V3 variable regions of the 16S rRNA gene. Mock communities were included to benchmark the bioinformatics pipeline. Reads were processed using Usearch (Edgar 2010), clustered based on a 97 % similarity cutoff using Uparse (Edgar 2013)and identified using the GreenGenes training set. The specific conductivity, pH, water content, and total (TC),total organic (TOC) and inorganic (IC) carbon content were determined and used as explanatory variables in direct ordination analyses of both the ARISA and the Illumina data. The Illumina sequencing resulted in ~600.000 high quality sequences divided over ~3980 OTUs in 28 phyla and 219 genera. No significant differences in richness equaling the number of OTUs after standardization for the number of sequences per samples were observed between high, medium and low TOC content classes for the sequencing data. Redundancy Analysis revealed that bedrock type (granite or gneiss), water content, specific conductance, pH and TOC significantly shaped the bacterial community composition. The ARISA dataset, despite having a lower taxonomic resolution, showed very similar patterns and relationships with environmental data, among which bedrock type remained the most important parameter in explaining differences in community structure between the samples. As the gneiss is supposedly of granite origin, differences in community structure may be related to physical differences between both bedrock types and their weathering products. Preliminary cosmogenic analysis of Pb isotopes of gravel samples indeed suggest a predominantly local origin of the material, yet mixtures with exotic material cannot be excluded in samples from gneiss outcrops. We conclude that microbial community composition is primarily driven by mineralogical characteristics of weathering products in these poorly developed soils, while biotic influences are of secondary importance. [less ▲]

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See detailBIOGEOGRAPHIC PATTERNS IN ANTARCTIC LACUSTRINE PROKARYOTES
Tytgat, Bjorn; Verleyen, Elie; Sweetlove, Maxime et al

Poster (2015, September 07)

Amplified climate change, increased human activity and the introduction of alien species likely form the biggest threat to Antarctic terrestrial ecosystems through range size expansions and contractions ... [more ▼]

Amplified climate change, increased human activity and the introduction of alien species likely form the biggest threat to Antarctic terrestrial ecosystems through range size expansions and contractions, regional extirpation and impacts on ecosystem functions. Despite their crucial role in the functioning of Antarctic terrestrial ecosystems , little is known about the present -day diversity and biogeography of microorganisms such as prokaryotes and microeukaryotes in the Antarctic Biogeographic Realm. Furthermore, identification of the key processes underlying microbial biodiversity dynamics is essential to understand and predict the consequences of global change on Antarctic lacustrine ecosystems. We analysed bacterial biodiversity in a total of 152 lacustrine microbial mat samples, distributed over the three main Biogeographic regions in the Antarctic Realm, including continental Antarctica, Maritime Antarctica and the Sub-Antarctic Islands comprising the southern Indian Ocean Province (SIOP) and the southern Pacific Ocean Province (SPOP). We targeted the V1-V3 variable regions of the 16S rRNA gene. Amplicon sequencing was done on an Illumina PE300 MiSeq. Sequences were processed using Usearch and Uparse, Mothur and custom scripts for basic parsing. An OTU cut-off was defined at 97 % sequence similarity, and sequences were mapped against a local GreenGenes database. Downstream analyses were performed using several R packages. We obtained about three million high quality sequences, with an average length of 500 bp. Sequences belonged to 8237 OTUs, and were distributed over 51 phyla and 366 genera. In addition, 649 OTUs remained unclassified at the phylum level and 6263 at the genus level. Mean OTU richness differed strongly between the four biogeographic regions. The lakes from Maritime Antarctica had a higher richness than those from Continental Antarctica. Interestingly, in sub-Antarctica OTU richness was strongly variable, with Marion Island (SIOP) having the lowest and Macquarie Island (SPOP) having on average the highest diversity of all studied regions. Multivariate Analyses showed that microbial community composition varied between biogeographic regions, with Macquarie Island being most different from the other regions. Continental Antarctica, Maritime Antarctica and the lakes from the SIOP share many OTUs, both in the case of Cyanobacteria and other bacteria, but are also characterised by a considerable number of unique OTUs. Within Antarctica, some regions harbour distinct bacterial communities such as the lakes in Schirmacher Oasis, Dronning Maud Land, and those from the eastern and western part of the Antarctic Peninsula. [less ▲]

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See detailThe BCCM/ULC culture collection to conserve, document and explore the polar cyanobacterial diversity
Wilmotte, Annick ULg; Renard, Marine ULg; Kleinteich, Julia et al

Poster (2015, September 07)

In 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 form benthic microbial mats ... [more ▼]

In 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 form 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 environmental 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.). The collection is available for researchers to study the taxonomy, evolution, adaptations to extreme environmental conditions, and genomic make-up. It presently includes 200 cyanobacterial strains, with 123 being of polar origin (catalogue: 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. The large diversity is also supported by the phylogenetic analyses based on the 16S rRNA sequences. This broad distribution makes the BCCM/ULC collection particularly interesting for phylogenomic studies. To this end, the sequencing of the complete genome of 16 selected strains is currently under way. In addition, cyanobacteria produce a wide range of secondary metabolites (e.g. alkaloides, cyclic and linear peptides, polyketides) with different bioactive potential (e.g. antibiotic, antiviral, anticancer, cytotoxic, genotoxic). Bioassays have shown antifungal activities of the cell extracts from strains Plectolyngbya hodgsonii ULC009 and Phormidium priestleyi ULC026. The potential of the polar strains to produce cyanotoxins and other secondary metabolites is currently being studied by ELISA, LC-MS and the detection of genes involved in their production. Due to the geographic isolation and the strong environmental stressors of the habitat, the exploration of these metabolites in Antarctic cyanobacterial strains seems promising for biotechnology or biomedical applications (Biondi et al. 2008). In summary, the BCCM/ULC public collection could serve as a Biological Resource Centre (OECD 2001) to conserve and document the biodiversity of polar cyanobacteria, as well as a repository for discovery of novel bioactive compounds. REFERENCES Biondi, N., Tredici, M., Taton, A., Wilmotte, A., Hodgson, D., Losi, D., & Marinelli, F. (2008) : Cyanobacteria from benthic mats of Antarctic lakes as a source of new bioactivities. Journal of Applied Microbiology, 105(1) : 105- 115 OECD (2001) Biological Resource Centres : Underpinning the Future of Life Sciences and Biotechnology. http://www.oecd.org/science/biotech/2487422.pdf [less ▲]

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See detailA next-generation protocol for the assessment of cyanobacterial diversity
Stelmach Pessi, Igor ULg; de Carvalho Maalouf, Pedro; Laughinghouse IV, Haywood Dail et al

Poster (2015, September)

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See detailBaseline data on the cyanobacterial diversity of Svalbard assessed by pyrosequencing
Laughinghouse IV, Haywood Dail; Stelmach Pessi, Igor ULg; Velázquez, David et al

Poster (2015, September)

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See detailGenome sequencing of an endemic filamentous Antarctic cyanobacterium
Lara, Yannick ULg; Verlaine, Olivier ULg; Kleinteich, Julia et al

Poster (2015, August 03)

The strain Phormidium priestleyi ULC007 was isolated from a benthic mat located in a shallow freshwater pond in the Larsemann Hills (69°S), Western Antarctica. This strain belongs to a cyanobacterial ... [more ▼]

The strain Phormidium priestleyi ULC007 was isolated from a benthic mat located in a shallow freshwater pond in the Larsemann Hills (69°S), Western Antarctica. This strain belongs to a cyanobacterial cluster that appeared as potentially endemic (Taton et al. 2006). After obtaining an axenic isolate, we sequenced the genome of this strain in the frame of the BELSPO CCAMBIO project, in order to better understand the functioning, metabolism and adaptative strategies of cyanobacteria to the extreme Antarctic environment. [less ▲]

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See detailThe BCCM/ULC collection : a Biological Ressource Center for polar cyanobacteria
Wilmotte, Annick ULg; Renard, Marine ULg; Lara, Yannick ULg et al

Poster (2015, August 03)

In this study, during the 2013 MicroFun expedition, we sampled 72 locations around Svalbard including diverse biotopes such as glacial forefields, tundra soils, hot springs, soil crusts, microbial mats ... [more ▼]

In this study, during the 2013 MicroFun expedition, we sampled 72 locations around Svalbard including diverse biotopes such as glacial forefields, tundra soils, hot springs, soil crusts, microbial mats, wet walls, cryoconites, plankton and periphyton, in order to (1) assess the biodiversity of cyanobacteria around Svalbard, (2) verify the existence of biogeographical trends around the archipelago, and (3) compare these data with other polar (cold) areas, especially Antarctica. We used a pyrosequencing approach targeting cyanobacteria-specific 16S rRNA gene sequences to deeply study the cyanobacterial communities. [less ▲]

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See detailA next-generation approach to assess the cyanobacterial diversity and biogeography in the High Arctic (Svalbard)
Laughinghouse, Haywood Dail; Stelmach Pessi, Igor ULg; Velazquez, David et al

Poster (2015, August 03)

Polar ecosystems are extremely sensitive to global climate changes and human activities. Cyanobacteria are key photosynthetic organisms in these latitudes, due to their roles in soil aggregation, nitrogen ... [more ▼]

Polar ecosystems are extremely sensitive to global climate changes and human activities. Cyanobacteria are key photosynthetic organisms in these latitudes, due to their roles in soil aggregation, nitrogen fixation, carbon cycles, and secondary metabolite production, among others. Previous works indicate that different cyanobacterial taxa/communities have different impacts on the environment, in both biogeochemical cycles and bioactive compound productions. Furthermore, the presence of biogeographical patterns in microorganisms, as found in macroorganisms, is an ongoing debate. In this study, during the 2013 MicroFun expedition, we sampled 72 locations around Svalbard including diverse biotopes such as glacial forefields, tundra soils, hot springs, soil crusts, microbial mats, wet walls, cryoconites, plankton and periphyton, in order to (1) assess the biodiversity of cyanobacteria around Svalbard, (2) verify the existence of biogeographical trends around the archipelago, and (3) compare these data with other polar (cold) areas, especially Antarctica. We used a pyrosequencing approach targeting cyanobacteria-specific 16S rRNA gene sequences to deeply study the cyanobacterial communities. [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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