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

in Astrobiology (in press)

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

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

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See detailCephalothrix gen. nov. (Cyanobacteria): towards an intraspecific phylogenetic evaluation by multilocus analyses
Malone, Camila da Silva Francieli; Rigonato, Janaina; Laughinghouse, Haywood Dail et al

in International Journal of Systematic and Evolutionary Microbiology (in press)

For more than a decade, the taxonomy of Phormidiaceae has been problematic, since morphologically similar organisms represent phylogenetically distinct entities. Based on 16S rRNA analyses, the ... [more ▼]

For more than a decade, the taxonomy of Phormidiaceae has been problematic, since morphologically similar organisms represent phylogenetically distinct entities. Based on 16S rRNA analyses, the polyphyletic genus Phormidium and other gas-vacuolated oscillatorioids appear scattered throughout the cyanobacterial tree of life. Recently, several studies have focused on understanding the oscillatorioid taxa at the generic level. At the specific level, there are few studies characterizing cyanobacterial strains using combined datasets (morphology, ultrastructure, and molecular multi-locus analyses). Using a multi-facet approach, we propose a new, well-defined genus, Cephalothrix gen. nov., by analyzing seven filamentous strains morphologically 'intermediate' between gas-vacuolated taxa and Phormidium. Furthermore, we characterize two new species: Cephalothrix komarekiana (CCIBt 3277, CCIBt 3279, CCIBt 3523, CCALA 155, SAG 75.79, and UTEX 1580) and Cephalothrix lacustris (CCIBt 3261). The generic name and specific epithets were proposed under the provisions of the International Code of Nomenclature for algae, fungi, and plants. [less ▲]

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See detail‘Ex-situ’ preservation and characterization of Antarctic cyanobacteria in the BCCM/ULC collection
Kleinteich, Julia ULg; Renard, Marine ULg; Simons, Véronique et al

Poster (2015, June 09)

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. An ISO9001 certificate was obtained for the public deposition and distribution of ... [more ▼]

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. 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 160 public 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 main holding of the collection concerns (sub)polar strains isolated from different biotopes and representative of a large taxonomic diversity. The molecular characterization is underway, on the basis of 16S rRNA and ITS sequences, but also Multiple Locus Sequence Analysis and genome sequencing. In addition, cyanobacteria are known to produce a range of secondary metabolites (e.g. alkaloides, cyclic and linear peptides, polyketides) with various bioactive potential. The presence of genes involved in the production of microcystin is currently studied by PCR, and analytical methods are used to confirm the toxin 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. [less ▲]

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See detailAn encapsulation-dehydration method for the long-term storage of cyanobacterial strains in the BCCM/ULC collection.
Crahay, Charlotte ULg; Mari, Maude; Wilmotte, Annick ULg

Poster (2015, May 13)

Long-term genetic and functional stability is a fundamental requirement for the maintenance of microorganisms. Cryopreservation is the preferred method for the long-term storage of many micro-organisms ... [more ▼]

Long-term genetic and functional stability is a fundamental requirement for the maintenance of microorganisms. Cryopreservation is the preferred method for the long-term storage of many micro-organisms, including cyanobacteria. The BCCM/ULC collection currently holds over 200 cyanobacterial strains as living cultures, but only 62 are maintained in a cryo-preserved state. The main limiting factors are the low levels of survival of some strains, as well as the long periods required to recover from cryopreservation, and thus the inability to rapidly deliver strains to clients.. The BRAIN-be project PRESPHOTO (preservation of photosynthetic micro-algae in the BCCM collections) (www.presphoto.ulg.ac.be) aims to improve the preservation of cyanobacterial and diatoms in the BCCM/ULC and BCCM/DCG collections, respec-tively. The encapsulation-dehydration is often considered as a promising alternative to the traditional cryopreservation method for recalcitrant microalgal strains. In this technique, cyanobacterial cultures are entrapped in calcium-alginate beads, osmotically dehydrated (traditionally with sucrose solutions), then evaporatively desiccated in a sterile air flow, or over silica gel and subsequently cryopreserved. In this study, the encapsulation-dehydration method was evaluated as potential long-term preservation technique of cyanobacterial strains. The effects of several factors on the viability of 4 strains have been investigated to determine which are the most important for the successful cryopreservation. In particular, several cryoprotectants (i.e. sucrose, PEG or mannitol), methods of beads dehydration (i.e. under a laminar flow or with silica gel) were tested. We have also compared storage at -70°C and in liquid nitrogen (-196oC). A pre-cultivation step in KCl was also tested for its ability to enhance desiccation tolerance. In addition, the use of alginate dissolution buffer following thawing was also considered. In the final phase of the project, the selected cryopreservation protocols will be tested on a large set of strains. In addition, an independent validation of the protocols will be also performed by both partners of the project (BCCM/DCG and the Culture Collection of Algae and Protozoa). [less ▲]

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See detailPRESPHOTO project - Preservation of microalgae in the BCCM collections
Crahay, Charlotte ULg; Deprez, Karolien; Vanormelingen, Pieter et al

Poster (2015, May)

The implementation of reliable preservation technologies of the biological resources is crucial for the management of the Biological Ressources Centers. PRESPHOTO, a BRAIN.be project, aims to develop and ... [more ▼]

The implementation of reliable preservation technologies of the biological resources is crucial for the management of the Biological Ressources Centers. PRESPHOTO, a BRAIN.be project, aims to develop and optimize new and cost-effective preservation techniques of photosynthetic microalgae (diatoms and cyanobacteria) in the two BCCM collections, BCCM/DCG and BCCM/ULC. This is a critical factor for the future growth and valorisation of these collections. Firstly, the traditional two-step cryopreservation technique will be adapted to photosynthetic microalgae strains. In particular, we will examine the effects of the culture conditions, the type and concentration of cryoprotectants, and the preservation temperature on the survival of microalgae. The encapsulation/dehydration technique as alternative to the two-step cryopreservation method will be also evaluated. Moreover, an independent validation of the developed protocols will be performed by the Culture Collection of Algae and Protozoa (UK) (subcontractor). Secondly, we will perform genome resequencing of selected strains to investigate the genetic changes induced by different cryopreservation techniques. Finally, a high-quality genomic DNA bank will be established and validated. [less ▲]

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See detailUse of 454 pyrosequencing protocol for the assessment of cyanobacterial diversity
Stelmach Pessi, Igor ULg; De Carvalho, Pedro; Laughinghouse, Haywood Dail et al

Poster (2015, May)

A pilot run was carried out on Antarctic microbial mat samples in order to test different protocols for 454 pyrosequencing and bioinformatic analyses. An artificial community was assembled using22 ... [more ▼]

A pilot run was carried out on Antarctic microbial mat samples in order to test different protocols for 454 pyrosequencing and bioinformatic analyses. An artificial community was assembled using22 cyanobacterial strains in two different abundance distributions. Bioinformatic analyses were carried out on the artificial communities using variations of the mothur and UPARSE pipelines. Moreover, different DNA extraction methods, technical replicates and biases arising from direct barcoded primer amplification were assessed using five microbial mat and soil crust samples. A great variation in richness estimates was observed using different bioinformatic pipelines, with UPARSE generating the most consistent results. On the other hand, community structures observed using different DNA extraction protocols were statistically similar. The same was observed for the technical replicates. Moreover, the use of barcoded primers did not influence the observed community structure. [less ▲]

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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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