References of "Wilmotte, Annick"
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See detailPhylogenetic analysis of cultivation-resistant terrestrial cyanobacteria with massive sheaths (Stigonema spp. and Petalonema alatum, Nostocales, Cyanobacteria) using single-cell and filament sequencing of environmental samples
Mares, Jan; Lara, Yannick ULg; Dadakova, Ina et al

in Journal of Phycology (2015), 51(2), 288297

Molecular assessment of a large portion of traditional cyanobacterial taxa has been hindered by the failure to isolate and grow them in culture. In this study, we developed an optimized protocol for ... [more ▼]

Molecular assessment of a large portion of traditional cyanobacterial taxa has been hindered by the failure to isolate and grow them in culture. In this study, we developed an optimized protocol for single cell/filament isolation and 16S rRNA gene sequencing of terrestrial cyanobacteria with large mucilaginous sheaths, and applied it to determine the phylogenetic position of typical members of the genera Petalonema and Stigonema. A methodology based on a glass-capillary isolation technique and a semi-nested PCR protocol enabled reliable sequencing of the 16S rRNA gene from all samples analyzed. Ten samples covering seven species of Stigonema from Europe, North and Central America, and Hawaii, and the type species of Petalonema from Slovakia were sequenced. Contrary to some previous studies, which proposed a relationship with heteropolar nostocalean cyanobacteria, Petalonema appeared to belong to the family Scytonemataceae. Analysis of Stigonema specimens recovered a unique coherent phylogenetic cluster, substantially broadening our knowledge of the molecular diversity within this genus. Neither the uni- to biseriate species nor the multiseriate species formed monophyletic subclusters within the genus. Typical multiseriate species of Stigonema clustered in a phylogenetic branch derived from uni- to biseriate S. ocellatum Thuret ex Bornet & Flahault in our analysis, suggesting that species with more complex thalli may have evolved from the more simple ones. We propose the technique tested in this study as a promising tool for a future revision of the molecular taxonomy in cyanobacteria. [less ▲]

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See detailProtection of Antarctic microbial communities–‘out of sight, out of mind’
Hughes, Kevin; Cowan, Don; Wilmotte, Annick ULg

in Frontiers in Microbiology (2015), 6(151), 1-6

RecentadvancesinmolecularbiologytechniqueshaveshownthepresenceofdiversemicrobialcommunitiesandendemicspeciesinAntarctica.Endemicmicrobesmaybeapotentialsourceofnovelbiotechnologicallyimportantcompounds ... [more ▼]

RecentadvancesinmolecularbiologytechniqueshaveshownthepresenceofdiversemicrobialcommunitiesandendemicspeciesinAntarctica.Endemicmicrobesmaybeapotentialsourceofnovelbiotechnologicallyimportantcompounds,including,forexample,newantibiotics.Thus,thescientificandbiotechnologicalvalueofAntarcticterrestrialmicrobialhabitatscanbecompromisedbyhumanvisitationtoagreaterextentthanpreviouslyrealized.Theever-increasinghumanfootprintinAntarcticamakesconsiderationofthistopicmorepressing,asthenumberoflocationsknowntobepristinehabitats,whereincreasinglysophisticatedcutting-edgeresearchtechniquesmaybeusedtotheirfullpotential,declines.ExaminationoftheProtectedAreassystemoftheAntarcticTreatyshowsthatmicrobialhabitatsaregenerallypoorlyprotected.NoothercontinentonEarthisdominatedtothesamedegreebymicrobialspecies,andrealopportunitiesexisttodevelopnewwaysofconceptualizingandimplementingconservationofmicrobialbiogeographyonacontinentalscale.Herewehighlightpotentialthreatsbothtotheconservationofterrestrialmicrobialecosystems,andtofuturescientificresearchrequiringtheirstudy. [less ▲]

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

Conference (2015, February)

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

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

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See detailMolecular diversity of microorganisms in Antarctic lacustrine microbial mats
Wilmotte, Annick ULg; Stelmach Pessi, Igor ULg; Sweetlove, Maxime et al

Conference (2015, February)

The BeSPO 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 BeSPO 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), strain isolation, and molecular diversity assessment using Next Generation Sequencing. The samples were collected in different Antarctic and sub-Antarctic biogeographical regions. 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. A new Scenedesmacean species was described from Antarctica, Chodatodesmus australis. A comparison of the bacterial diversity retrieved by cultivation or NGS showed a complementarity of both approaches and differences when different variable regions of the 16S rRNA gene were used. Novel and unclassified sequences, also observed by other authors, were obtained. Pilot studies were conducted for the microeukaryotes and cyanobacteria to select NGS protocols and bioinformatic pipelines. The purpose is to deposit the diversity data in the “Microbial Antarctic Resource System (MARS)” presently developed into the webportal ‘biodiversity.aq’. [less ▲]

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See detailGenome-wide transcriptional analysis suggests hydrogenase- and nitrogenase-mediated hydrogen production in Clostridium butyricum CWBI 1009
Calusinska, Magda; Hamilton, Christopher; Monsieurs, Pieter et al

in Biotechnology for Biofuels (2015), 8(27), 1-16

Background: Molecular hydrogen, given its pollution-free combustion, has great potential to replace fossil fuels in future transportation and energy production. However, current industrial hydrogen ... [more ▼]

Background: Molecular hydrogen, given its pollution-free combustion, has great potential to replace fossil fuels in future transportation and energy production. However, current industrial hydrogen production processes, such as steam reforming of methane, contribute significantly to the greenhouse effect. Therefore alternative methods, in particular the use of fermentative microorganisms, have attracted scientific interest in recent years. However the low overall yield obtained is a major challenge in biological H2 production. Thus, a thorough and detailed understanding of the relationships between genome content, gene expression patterns, pathway utilisation and metabolite synthesis is required to optimise the yield of biohydrogen production pathways. Results: In this study transcriptomic and proteomic analyses of the hydrogen-producing bacterium Clostridium butyricum CWBI 1009 were carried out to provide a biomolecular overview of the changes that occur when the metabolism shifts to H2 production. The growth, H2-production, and glucose-fermentation profiles were monitored in 20 L batch bioreactors under unregulated-pH and fixed-pH conditions (pH 7.3 and 5.2). Conspicuous differences were observed in the bioreactor performances and cellular metabolisms for all the tested metabolites, and they were pH dependent. During unregulated-pH glucose fermentation increased H2 production was associated with concurrent strong up-regulation of the nitrogenase coding genes. However, no such concurrent up-regulation of the [FeFe] hydrogenase genes was observed. During the fixed pH 5.2 fermentation, by contrast, the expression levels for the [FeFe] hydrogenase coding genes were higher than during the unregulated-pH fermentation, while the nitrogenase transcripts were less abundant. The overall results suggest, for the first time, that environmental factors may determine whether H2 production in C. butyricum CWBI 1009 is mediated by the hydrogenases and/or the nitrogenase. Conclusions: This work, contributing to the field of dark fermentative hydrogen production, provides a multidisciplinary approach for the investigation of the processes involved in the molecular H2 metabolism of clostridia. In addition, it lays the groundwork for further optimisation of biohydrogen production pathways based on genetic engineering techniques. [less ▲]

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See detailPRESPHOTO – a project to improve the preservation of cyanobacteria and diatom cultures
Deprez, Karolien; Vanormelingen, Pieter; Crahay, Charlotte ULg et al

Poster (2014, November 18)

The availability of biological material of guaranteed identity and quality in Biological Resource Centers is considered fundamental for scientific research and R&D, but depends heavily on adequate ... [more ▼]

The availability of biological material of guaranteed identity and quality in Biological Resource Centers is considered fundamental for scientific research and R&D, but depends heavily on adequate preservation methods. We present a new BRAIN-BE project on improving the preservation of two groups of photosynthetic microorganisms, cyanobacteria and diatoms, in two collections of the Belgian Co-ordinated Collections of Micro-organisms (BCCM). First, we will improve the cultivation success of diatoms from different habitats by testing different culture media. For organisms that keep resisting cultivation, we will develop DNA extraction and amplification, as well as morphological investigation based on single cells. Secondly, we will design and validate improved cryopreservation protocols for both diatoms and cyanobacteria, since cryopreservation is now the preferred method for the long-term storage of microalgal cultures. For that, the two-step cryopreservation method will be tested using several cryoprotectants and strains in different growth stages. Moreover, this will be compared with the encapsulation/dehydration method. For cyanobacteria, viability tests will be performed with vital dyes whereas diatoms’ survival will be assessed by PAM fluorometry. In addition, genome resequencing will be applied to determine the impact of the cryopreservation protocol(s) on genomic stability. Finally, a genomic DNA bank will be constructed and validated. This is highly complementary to preservation as living strains, given that some users require only genomic DNA and it may not be feasible to preserve the global microalgal species diversity as living cultures. [less ▲]

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See detailInternational Committee on Systematics of Prokaryotes. Subcommittee on the taxonomy of phototrophic bacteria: Minutes of the meetings, 11 August 2009, Montreal, Canada
Imhoff, Johannes; Wilmotte, Annick ULg

in International Journal of Systematic and Evolutionary Microbiology (2014), 64

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See detailThe phycologist Pierre Compère: his contribution to cyanobacterial studies
Golubic, Stjepko; Wilmotte, Annick ULg

in Plant Ecology and Evolution (2014), 147(3), 307-310

At the occasion of the 80th birthday of Pierre Compère, his rich career as a phycologist and cyanobacteriologist is placed in the context of the advances of the scientific theories, the evolution of the ... [more ▼]

At the occasion of the 80th birthday of Pierre Compère, his rich career as a phycologist and cyanobacteriologist is placed in the context of the advances of the scientific theories, the evolution of the cyanobacterial taxonomy and the nomenclatural discussions linked to the utilization of two different Codes of nomenclature. [less ▲]

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See detailTHE BCCM/ULC CULTURE COLLECTION TO CONSERVE AND STUDY THE DIVERSITY OF (SUB)POLAR CYANOBACTERIA
Wilmotte, Annick ULg; Renard, Marine ULg; Kleinteich, Julia et al

Poster (2014, September)

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. A Quality Management System was implemented and is continuously improved since then ... [more ▼]

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. A Quality Management System was implemented and is continuously improved since then. An ISO9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. BCCM/ULC is currently holding 134 cyanobacterial strains and the catalogue is available on http://bccm.belspo.be/catalogues/ulc-catalogue-search. 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. The collection includes 113 (sub)polar strains. In such extreme environments, cyanobacteria are important phototrophs and primary producers in terrestrial and freshwater ecosystems. The purpose of this collection is to gather a representative portion of the cyanobacterial diversity with different ecological origins (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.) and make it available for researchers to study the taxonomy, evolution, adaptations to environmental conditions, and genomic make-up. Thus, 102 cyanobacterial strains were isolated from the three main biogeographic zones of the Antarctic continent. In addition, 7 strains were isolated in Arctic biotopes and 4 from Siberian lakes. The molecular characterization is underway, on the basis of 16S rRNA and ITS sequences. Moreover, a Multilocus Sequence Analysis is tested on diverse strains to improve their systematics. The diversity encompasses the three main cyanobacterial orders: Chroococcales, Oscillatoriales and Nostocales. In addition, cyanobacteria are known to produce a range of secondary metabolites (e.g. alkaloides, cyclic and linear peptides, polyketides) with different bioactive properties (e.g. antibiotic, antiviral, antifungal, anticancer). The potential of the polar strains to produce cyanotoxins is currently studied by ELISA and the detection by PCR 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. [less ▲]

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See detailUnveiling biogeographic patterns of Antarctic cyanobacteria by 454 pyrosequencing
Wilmotte, Annick ULg; Stelmach Pessi, Igor ULg; De Carvalho, Pedro et al

Poster (2014, August)

Cyanobacteria are often considered as the dominant phototrophs in Antarctic lacustrine environments, primarily occurring in benthic or floating microbial mat communities. Previous studies have indicated ... [more ▼]

Cyanobacteria are often considered as the dominant phototrophs in Antarctic lacustrine environments, primarily occurring in benthic or floating microbial mat communities. Previous studies have indicated the presence of endemic cyanobacteria in the Antarctic Realm, but the extent and patterns of cyanobacterial bioregionalisation, if any, is still largely unknown. Therefore, our objective is to assess the cyanobacterial diversity in Antarctic lacustrine microbial mats using 454 pyrosequencing, in order to determine if cyanobacterial biogeographic patterns are similar to those observed for multicellular organisms. This will be useful also as baseline data, for later comparisons and assessments of the impact of global change. [less ▲]

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See detailEx-situ’ conservation of Antarctic cyanobacteria : a culture collection to explore diversity and bioactivity
Wilmotte, Annick ULg; Renard, Marine ULg; Kleinteich, J et al

Poster (2014, August)

Cyanobacteria appear as the dominant phototrophs in Antarctic terrestrial and freshwater ecosystems. Since 2011, the Belgian Science Policy Office has funded the BCCM/ULC public collection of (sub)polar ... [more ▼]

Cyanobacteria appear as the dominant phototrophs in Antarctic terrestrial and freshwater ecosystems. Since 2011, the Belgian Science Policy Office has funded the BCCM/ULC public collection of (sub)polar cyanobacteria. It is currently holding 102 Antarctic cyanobacterial strains and the catalogue is available on http://bccm.belspo.be/db/ulc_search_form.php. A Quality Management System was implemented and an ISO9001 certificate was obtained for the public deposition and distribution of strains. The strains are kept as living cultures, and their cryopreservation is in progress. The Antarctic cyanobacterial strains were isolated from samples of the three main biogeographic provinces. The purpose of this public collection is to gather a representative portion of the cyanobacterial diversity with different ecological origins (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.) and make it available for researchers to study the diversity, evolution, adaptations to the environmental conditions, and genomic make-up. Three cyanobacterial orders are represented: Chroococcales, Oscillatoriales and Nostocales. This is particularly important in view of the emerging use of metagenomic approaches on environmental samples, where the comparisons with the genome sequences from well-defined strains is very useful. They could also serve as references for compounds such as fatty acids and pigments. In addition, cyanobacteria produce a 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 of strains Plectolyngbya hodgsonii ULC009 and Phormidium priestleyi ULC026. Due to the geographic isolation and the strong environmental stressors of the habitat, the exploration of these metabolites in Antarctic cyanobacterial strains seems especially promising for biotechnology or biomedical applications. In summary, the BCCM/ULC public collection could serve as a general reference for Antarctic cyanobacteria with multiple applications, as well as a resource for novel bioactive compounds. [less ▲]

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

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

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

Conference (2014, June 24)

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

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

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See detailThe BCCM/ULC collection to safeguard and exploit polar cyanobacterial diversity
Wilmotte, Annick ULg

Conference (2014, June 21)

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See detailBCCM/ULC, a culture collection to explore diversity and bioactivity of (sub)polar cyanobacteria
Wilmotte, Annick ULg; Renard, Marine ULg; Kleinteich, Julia et al

Poster (2014, June)

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. A Quality Management System was implemented and is continuously improved since then ... [more ▼]

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. A Quality Management System was implemented and is continuously improved since then. An ISO9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. BCCM/ULC is currently holding 134 cyanobacterial strains and the catalogue is available on http://bccm.belspo.be/catalogues/ulc-catalogue-search 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. The collection includes 113 (sub)polar strains. In such extreme environments, cyanobacteria are important phototrophs and primary producers in terrestrial and freshwater ecosystems. The purpose of this public collection is to gather a representative portion of the cyanobacterial diversity with different ecological origins (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.) and make it available for researchers to study the taxonomy, evolution, adaptations to environmental conditions, and genomic make-up. Thus, 102 cyanobacterial strains were isolated from the three main biogeographic zones of the Antarctic continent. In addition, 7 strains were isolated in Arctic biotopes and 4 from Siberian lakes. The molecular characterization is underway, on the basis of 16S rRNA and ITS sequences. The diversity encompasses the three main cyanobacterial orders: Chroococcales, Oscillatoriales and Nostocales. This is particularly important in view of the emerging use of metagenomic approaches on environmental samples, where the comparisons with the genome sequences from well-defined strains is very useful. In addition, cyanobacteria are known to produce a range of secondary metabolites (e.g. alkaloides, cyclic and linear peptides, polyketides) with different bioactive potential (e.g. antibiotic, antiviral, antifungal, anticancer, cytotoxic). The potential of the polar strains to produce cyanotoxins is currently studied by ELISA and the detection by PCR 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 especially promising for biotechnology or biomedical applications. In summary, the BCCM/ULC public collection could serve as a general reference for (sub)polar cyanobacteria with multiple applications (pigments, UV screens, …), as well as a resource for novel bioactive compounds [less ▲]

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See detailAssessment of bioinformatic pipelines for the analysis of 454 pyrosequencing data using artificial cyanobacterial communities
Stelmach Pessi, Igor ULg; De Carvalho Maalouf, Pedro; Laughinghouse IV, Haywood ULg et al

Poster (2013, November 27)

The field of microbial ecology has undergone a revolution with the advent of next-generation sequencing (NGS) technologies, which revealed a higher microbial diversity than what was previously observed ... [more ▼]

The field of microbial ecology has undergone a revolution with the advent of next-generation sequencing (NGS) technologies, which revealed a higher microbial diversity than what was previously observed. The possibility of analyzing tens to hundreds of thousands sequences in a single sequencing run has provided information on rare taxa that could constitute an important fraction of microbial communities. However, this comes with the cost of relatively high error rates for individual reads, which can lead to overestimation of diversity due to the generation of spurious Operational Taxonomic Units (OTUs) consisting of erroneous sequences. Therefore, a correct assessment of microbial diversity using NGS relies on robust bioinformatic tools in order to correct for PCR and sequencing biases. Here we report on community structures recovered for two artificial cyanobacterial communities applying three commonly used and two recently published bioinformatic pipelines. This pilot study was made in the frame of the BELSPO project CCAMBIO. Artificial communities were constructed using DNA isolated from 22 cyanobacterial strains from the BCCM/ULC Polar Cyanobacteria Collection (http://bccm.belspo.be/about/ulc.php). DNA was extracted from individual cultures and pooled at equal (community Art1) or tiered (community Art2) concentrations. The V3-V4 hypervariable region of the 16S rRNA gene was amplified by PCR using primers 359F and 781Ra/781Rb [Nübel et al (1997) Appl Environ Microbiol 63: 3327-3332], and amplicons were sequenced on a 454 GS FLX Titanium platform. Data was demultiplexed and submitted to five bioinformatic pipelines for quality control of reads, removal of chimeric sequences and Operational Taxonomic Units (OTUs) clustering: (I) “shhh.flows (450 flows)”, (II) “shhh.flows (360-720 flows)” and (III) “Sliding Window (Q35, 50 bp)”, using MOTHUR according to Schloss et al (2011) [Schloss et al (2011) PLOS One 6: e27310]; (IV) “fastq_maxee” and (V) “fastq_truncqual”, using UPARSE according to Edgar (2013) [Edgar (2013) Nat Methods 10: 996-998]. Average sequence length varied considerably among pipelines, with pipeline I generating shorter reads (220 bp in average) and pipelines IV and V longer reads (370 bp). The number of OTUs obtained in each pipeline also varied significantly. While 22 and 21 OTUs were obtained for pipelines IV and V, respectively, pipelines I-III generated a surprisingly high number of OTUs (199, 317 and 289, respectively). Despite differences in the number of OTUs, the relative abundance of each reference strain did not differ significantly between pipelines. Overall, community structures observed using the UPARSE protocol (pipelines IV and V) were the most consistent with the expected results. These findings show the importance of assessing the performance of different bioinformatic pipelines using artificial communities, in order to reduce the effects of PCR and sequencing errors, which can lead to distorted community structures estimates. [less ▲]

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See detailStudy and conservation of Antarctic cyanobacterial diversity in the BCCM/ULC collection
Wilmotte, Annick ULg; Renard, Marine; Ould Amer, Yasmine et al

Poster (2013, July)

The BCCM/ULC public collection presently includes 72 Antarctic cyanobacterial strains and its catalogue is available on http://bccm.belspo.be/db/ulc_search_form.php. An ISO9001 certificate was obtained ... [more ▼]

The BCCM/ULC public collection presently includes 72 Antarctic cyanobacterial strains and its catalogue is available on http://bccm.belspo.be/db/ulc_search_form.php. An ISO9001 certificate was obtained for the public deposition and distribution of strains. The purpose of this collection is to gather a representative sample of Antarctic cyanobacterial diversity from different biotopes (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.) and make it available for researchers to study the diversity, evolution, physiology, and genomic make-up. This is particularly important in view of the emerging use of metagenomic approaches on environmental samples, where the comparison with well-defined strain genome sequences can be very useful. [less ▲]

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See detailBioregionalisation and biodiversity of Cyanobacterial communities in East- Antarctic lakes
De Carvalho Maalouf, Pedro ULg; Stelmach Pessi, Igor ULg; Verleyen, Elie et al

Poster (2013, July)

On the Antarctic continent, ice-free regions represent only 0.3% of the total surface area. In these regions, cyanobacteria are one of the dominant phototrophs and primary producers, forming cohesive ... [more ▼]

On the Antarctic continent, ice-free regions represent only 0.3% of the total surface area. In these regions, cyanobacteria are one of the dominant phototrophs and primary producers, forming cohesive benthic mats in lakes and other aquatic habitats. Using a recent compilation of published biodiversity data from Antarctica and the sub-Antarctic islands in combination with physical factors and expert-defined bioregions, Terauds et al. (2012) identified 15 biologically distinct ice-free Antarctic Conservation Biogeographic Regions (ACBRs). However, the degree and nature of bioregionalisation in Antarctic cyanobacterial communities is still largely unknown. In this study, cyanobacterial diversity was analysed using Denaturating Gradient Gel Electrophoresis (DGGE) on a partial 16S rRNA sequence (ca 400 bp) in 50 microbial mats originating from five of the seven ACBRs identified in East Antarctica. Comparison of the sequences with those available in GenBank was carried out to assess the geographical distribution of the taxa on both local and global scales. A total of 35 Operational Taxonomic Units (OTUs, group of sequences with more than 98.5% sequence similarity) was obtained for all samples. Moreover, the taxonomic turnover between the five ACBRs was relatively low, as 69.5% of the OTUs were present in 2 or 3 bioregions. Consistent with previous findings, a large proportion (37%) of the OTUs was restricted to the “cold biosphere”, and 17% appeared potentially endemic to the Antarctic continent. These results suggest that the patterns of bioregionalisation in East Antarctic cyanobacteria are different than the ACBR scheme. Therefore, it would be useful to study the microbial bioregionalisation in more detail and using less conserved molecular taxonomic markers than the 16S rRNA gene, such as the ITS region. Moreover, since DGGE only provides information on the dominant taxa in microbial assemblages, a high-throughput screening is currently being performed. [less ▲]

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See detailBiodiversity studies in Open-Top Chambers in continental Antarctica
Mano, Marie-José ULg; Namsaraev, Zorigto; Obbels, Dagmar et al

Poster (2013, July)

Open Top Chambers are passive warming systems used to experimentally assess the effect of climate change on terrestrial ecosystems, and they were used in several Antarctic regions to study the response of ... [more ▼]

Open Top Chambers are passive warming systems used to experimentally assess the effect of climate change on terrestrial ecosystems, and they were used in several Antarctic regions to study the response of biotic communities. In the BELSPO BELDIVA project, OTCs were used in continental Eastern Antarctica, where environmental conditions are very extreme. In January 2010, 8 Open-Top Chambers (OTC) were installed in four ice-free regions of the Sör Rondane Mountains, namely on the Utsteinen ridge, the Tanngarden granite outcrop, the Teltet nunatak and the fourth nunatak of the Pingvinane range. [less ▲]

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