References of "Wilmotte, Annick"
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See detailFossil cyanobacterial DNA from sediment cores at Beak Island (Antarctic Peninsula): challenges for a molecular approach
Fernandez Carazo, Rafael ULg; Wilmotte, Annick ULg

in Decleir, Hugo; De Broyer, Claude; Dehairs, Frank (Eds.) et al CONTACTFORUM Belgian IPY symposium. The contribution of Belgian Research to the achievements of the International Polar Year 2007-2009 (2010)

Two sediment cores taken from lakes BK1 and BK2 in Beak Island (Trinity Peninsula, Antarctic Peninsula) were analysed. The cores were divided in two sections (lacustrine and marine). Changes in ... [more ▼]

Two sediment cores taken from lakes BK1 and BK2 in Beak Island (Trinity Peninsula, Antarctic Peninsula) were analysed. The cores were divided in two sections (lacustrine and marine). Changes in cyanobacterial diversity occurring within the lacustrine section, when the lake was isolated from the sea, were studied. [less ▲]

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See detailBelgian IPY Symposium 'The contribution of Belgian research to the achievements of the International Polar Year 2007-9
Dehairs, Frank; Decleir, Hugo; De Broyer, Claude et al

Book published by Universa Press (2010)

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See detailStructuring effects of climate-related environmental factors on Antarctic microbial mat communities
Verleyen, Elie; Sabbe, Koen; Hodgson, Dominic A et al

in Aquatic Microbial Ecology (2010), 59

Both ground-based and satellite data show that parts of Antarctica have entered a period of rapid climate change, which already affects the functioning and productivity of limnetic ecosystems. To predict ... [more ▼]

Both ground-based and satellite data show that parts of Antarctica have entered a period of rapid climate change, which already affects the functioning and productivity of limnetic ecosystems. To predict the consequences of future climate anomalies for lacustrine microbial communities, we not only need better baseline information on their biodiversity but also on the climaterelated environmental factors structuring these communities. Here we applied denaturing gradient gel electrophoresis (DGGE) of the small subunit ribosomal DNA (SSU rDNA) to assess the genetic composition and distribution of Cyanobacteria and eukaryotes in 37 benthic microbial mat samples from east Antarctic lakes. The lakes were selected to span a wide range of environmental gradients governed by differences in lake morphology and chemical limnology across 5 ice-free oases. Sequence analysis of selected DGGE bands revealed a high degree of potential endemism among the Cyanobacteria (mainly represented by Oscillatoriales and Nostocales), and the presence of a variety of protists (alveolates, stramenopiles and green algae), fungi, tardigrades and nematodes, which corroborates previous microscopy-based observations. Variation partitioning analyses revealed that the microbial mat community structure is largely regulated by both geographical and local environmental factors of which salinity (and related variables), lake water depth and nutrient concentrations are of major importance. These 3 groups of environmental variables have previously been shown to change drastically in Antarctica in response to climate change. Together, these results have obvious consequences for predicting the trajectory of biodiversity under changing climate conditions and call for the continued assessment of the biodiversity of these unique ecosystems. [less ▲]

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See detailAn efficient DNA isolation protocol for filamentous cyanobacteria of the genus Arthrospira
Morin, Nicolas ULg; Vallaeys, Tatiana; Hendrickx, Larissa et al

in Journal of Microbiological Methods (2010), 80

Thanks to their photosynthetic and nutritive properties, cyanobacteria of the Arthrospira genus are of interest as food supplements, as efficient oxygen producing life support system organisms for manned ... [more ▼]

Thanks to their photosynthetic and nutritive properties, cyanobacteria of the Arthrospira genus are of interest as food supplements, as efficient oxygen producing life support system organisms for manned space flight, and for the production of biofuels. Despite these potential valuable applications, full genome sequences and genetic information in general on Arthrospira remain scarce. This is mainly due to the difficulty to extract sufficient high molecular weight nucleic acids from these filamentous cyanobacteria. In this article, an efficient and reproducible DNA extraction procedure for cyanobacteria of the genus Arthrospira was developed. The method is based on the combination of a soft mechanical lysis with enzymatic disruption of the cell wall. The comparison with other extraction protocols clearly indicates that this optimised method allows the recovery of a larger amount of DNA. Furthermore, the extracted DNA presents a high molecular weight, a reduced degradation and an excellent overall quality. It can be directly used for molecular biology purposes such as PCR, and clone library construction. [less ▲]

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See detailOptimisation of culture conditions for biological hydrogen production by Citrobacter freundii CWBI952 in batch, sequenced-batch and semicontinuous operating mode
Hamilton, Christopher ULg; Hiligsmann, Serge ULg; Beckers, Laurent ULg et al

in International Journal of Hydrogen Energy (2010), 35

Investigations were carried out to determine the effect of the pH, the nitrogen source, iron and the dilution rate (h 1) on fermentative hydrogen production from glucose by the newly isolated strain ... [more ▼]

Investigations were carried out to determine the effect of the pH, the nitrogen source, iron and the dilution rate (h 1) on fermentative hydrogen production from glucose by the newly isolated strain Citrobacter freundii CWBI952. The hydrogen production rate (HPR), hydrogen yield, biomass and soluble metabolites were monitored at 30 C in 100 mL serum bottles and in a 2.3 L bioreactor operated in batch, sequenced-batch and semicontinuous mode. The results indicate that hydrogen production activity, formate biosynthesis and glucose intake rates are very sensitive to the culture pH, and that additional formate bioconversion and production of hydrogen with lower biomass yields can be obtained at pH 5.9. In a further series of cultures casein peptone was replaced by (NH4)2SO4, a low cost alternative nitrogen source. The ammonia-based substitute was found to be suitable for H2 production when a concentration of 0.045 g/L FeSO4 was provided. Optimal overall performances (ca. an HPR of 33.2 mL H2/L h and a yield of 0:83 molH2 =molglucose) were obtained in the semicontinuous culture applying the previously optimized parameters for pH, nitrogen, and iron with a dilution rate of 0.012 h 1 and degassing of biogas by N2 at a 28 mL/min flow rate. [less ▲]

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See detailThe diversity of clostridial hydrogenases revealed by genome sequencing projects
Calusinska, Magdalena ULg; Wilmotte, Annick ULg; Joris, Bernard ULg

Poster (2009, December 15)

Molecular hydrogen is a key intermediate in metabolomic interactions of a wide range of microorganisms. Hydrogen is also regarded as a key component in future energy systems as it is a sustainable, clean ... [more ▼]

Molecular hydrogen is a key intermediate in metabolomic interactions of a wide range of microorganisms. Hydrogen is also regarded as a key component in future energy systems as it is a sustainable, clean, and transportable energy carrier. Some microorganisms can produce hydrogen during a reversible reduction of protons to dihydrogen, a reaction which is catalyzed by the enzyme hydrogenases. On the basis of their bimetallocenter composition, hydrogenases are divided into three main groups, phylogenetically not related: [NiFe] hydrogenases, [Fe] only hydrogenases and FeS cluster free hydrogenases. The latter were described in methanogenic Archaea only. [NiFe] hydrogenases, composed of at least two subunits are well characterized and widely distributed between Archaea and Bacteria. However, only a few representatives of Clostridium sp. possess this type of enzyme. On the other hand, much less is known about the [Fe] only hydrogenases, that are usually monomeric enzymes and restricted to Bacteria and a few eukaryotic species. Genome sequencing projects gave a completely new insight into the diversity of forms of putative [Fe] only hydrogenases within the genus Clostridium. With the use of bioinformatic tools, we have described the unusual modularity of forms of these enzymes, from monomeric to tetrameric with a different number of accessory domains reacting with diverse redox partners. This fact seems to support the central role of hydrogenases in cell metabolism and quick adaptation of the host to changing environmental conditions. Moreover, the presence of multiple putative operons encoding for multisubunit [FeFe] hydrogenases is highlighting the fact that hydrogen metabolism is very complex in the Clostridium genus. [less ▲]

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See detailCyanobacterial 
molecular 
diversity 
and distribution 
in 
microbial 
mats from 
antarctic 
lakes
De Carvalho Maalouf, Pedro ULg; Lambion, Alexandre ULg; Zakhia, Frédéric et al

Poster (2009, December 11)

The coastal deglaciated areas of Antarctica hold lakes and other water bodies with a wide spectrum of limnological conditions. Aquatic habitats offer milder conditions to the microorganisms, which are the ... [more ▼]

The coastal deglaciated areas of Antarctica hold lakes and other water bodies with a wide spectrum of limnological conditions. Aquatic habitats offer milder conditions to the microorganisms, which are the only permanent inhabitants of this glacial desert. Among them, cyanobacteria are the first photosynthetic colonisers, sometimes forming thick, cohesive and pigmented benthic mats. In the frame of the BELSPO AMBIO project (Antarctic Microbial BIOdiversity, influence of geographical and ecological factors, www.ambio.ulg.ac.be), we have obtained benthic mat samples coming from lakes from various coastal regions of the continent (MERLIN 2007 and BELARE 2007 field campaigns and by collaborations). We have investigated cyanobacterial molecular diversity via Polymerase Chain Reaction and Denaturating Gradient Gel Electrophoresis (PCR-DGGE) on a set of 80 samples. We couple the numerical analysis of the obtained band patterns with the phylogenetic analysis of the sequences, and by using multivariate analysis, we will assess the role of the ecological and geographical factors shaping the distribution and the diversity of cyanobacteria. Preliminary results of the analysis of 13 samples seem to indicate that lakes separated by a small distance have different cyanobacterial communities, highlighting the importance of ecological factors. Fifty per cent of the obtained Operational Taxonomic Units (OTUs) are potentially endemic to Antarctica while others seem to have a global distribution. The completed study will give us a wide scale view on the distribution and the diversity of cyanobacteria in two biogeographical zones: Continental Antarctica and Maritime Antarctica. Finally, our studies will supply new data and arguments for the ongoing “everything is everywhere, but the environment selects” debate concerning microbial biogeography. [less ▲]

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See detailApplication of molecular techniques to monitor the evolution of bacterial consortia composed of Clostridium sp. in a hydrogen producing bioreactor
Calusinska, Magdalena ULg; Savichtcheva, Olga; Joris, Bernard ULg et al

Poster (2009, December 11)

Our current dependence on fossil fuels as the primary energy source contributes to global climate change, environmental degradation and health problems. Hydrogen offers a tremendous potential as a clean ... [more ▼]

Our current dependence on fossil fuels as the primary energy source contributes to global climate change, environmental degradation and health problems. Hydrogen offers a tremendous potential as a clean, renewable energy currency and it is compatible with electrochemical and combustion processes for energy conversion without producing carbon – based emissions. Many microorganisms, especially photosynthetic as well as facultative and anaerobic bacteria have been reported to produce large amounts of hydrogen from soluble and insoluble biomass. Clostridia, being obligate anaerobes, are capable of biogas production during ‘dark fermentation’ of a wide range of carbohydrates. In this ARC project, entitled Micro – H2 we have focused on a new direction in bio – hydrogen production systems which is the use of mixed cultures of microorganisms (consortia). We expect that the combination of complementary metabolisms could significantly increase the efficiencies of mixed systems compared to monocultures. However, a few fundamental studies need to be carried out in order to investigate and improve the stability of microbial populations involved in the processes. It is now recognised that molecular microbial ecology tools provide the scientific basis to monitor the processes used in environmental biotechnology. To characterize the diversity of bacterial communities, quantitative techniques such as Real – Time Quantitative PCR and FISH (Fluorescence in situ hybridization) and semi – quantitative DGGE (Denaturing Gradient Gel Electrophoresis) have been optimized and applied on different bioreactor samples. This approach enabled for the temporal monitoring of the evolution of bacterial consortia, both in terms of species dominance and their metabolic activity. Molecular analysis of bacterial consortia allowed for careful examination of interactions between different bacterial species within a consortium, which is crucial in the stabilization of the hydrogen production process. [less ▲]

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See detailThe diversity of Clostridial hydrogenases and biohydrogen production
Calusinska, Magdalena ULg; Savichtcheva, Olga; Masset, Julien ULg et al

Poster (2009, June 18)

Molecular hydrogen is a key intermediate in metabolomic interactions of a wide range of microorganisms. Hydrogen is also regarded as a key component in future energy systems as it is a sustainable, clean ... [more ▼]

Molecular hydrogen is a key intermediate in metabolomic interactions of a wide range of microorganisms. Hydrogen is also regarded as a key component in future energy systems as it is a sustainable, clean, and transportable energy carrier. Some microorganisms can produce hydrogen during a reversible reduction of protons to dihydrogen, a reaction which is catalyzed by hydrogenases [1]. Hydrogenases belong to an iron – sulphur protein family, that contains active sites consisting of inorganic sulfide and iron atoms bound to the polypeptide chain. On the basis of their bimetallocenter composition hydrogenases are divided into three main groups, phylogenetically not related: [NiFe] hydrogenases, [Fe] only hydrogenases and ‘metal – free hydrogenases’ which were described in methanogenic Archaea only. [NiFe] hydrogenases, composed of at least two subunits are well characterized and widely distributed between Archaea and Bacteria but only a few representatives of Clostridium possess this type of enzyme. On the other hand, [Fe] only hydrogenases, being usually monomeric enzymes and restricted to Bacteria and a few eukaryotic species are far less described. These proteins, being omnipresent catalysts of many biological reactions, are especially abundant in Clostridia. The physiological function of Clostridial [Fe] only hydrogenases is to dispose under the form of hydrogen, of the excess of reducing power generated during the fermentation of carbohydrates. The unusual diversity of forms of [Fe] only hydrogenases within Clostridia seems to support the central role of this enzyme in cell metabolism and to facilitate the quick adaptation of the host to changing environmental conditions. Moreover, the presence of multiple putative operons encoding for multisubunit [Fe] only hydrogenases in the genomes of sequenced Clostridium spp. is highlighting the need to study the new, not yet described function of these ostensibly simple proteins. In this project, we have focused our effort on the molecular characterization of key enzymes involved in the process of biohydrogen production with a special interest in Clostridium species. By applying molecular techniques on samples from different kinds of bioreactors, we want to select highly productive species in terms of hydrogen generation. We also believe that gene expression profiling will provide new data on the possible function and activity of different hydrogenases involved in the process. The better understanding of hydrogen metabolism is essential for its sustainable production. [less ▲]

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See detailThe biodiversity of cyanobacteria in Antarctic microbial mats
Wilmotte, Annick ULg; Fernandez-Carazo, Rafael; Zakhia, Frederic et al

Conference (2009)

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See detailDarwin en Antarctique: diversité et phylogénie
Wilmotte, Annick ULg

in Bulletin de la Société Royale des Sciences de Liège (2009), 78

In the first part, I imagine that Charles Darwin has visited Livingston Island in the Antarctic Peninsula. In the first part, our research on the cyanobacterial diversity in the region of the Belgian ... [more ▼]

In the first part, I imagine that Charles Darwin has visited Livingston Island in the Antarctic Peninsula. In the first part, our research on the cyanobacterial diversity in the region of the Belgian research station Princess Elisabeth is presented. [less ▲]

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See detailSeasonal cyanobacterial dynamics in a mesoeutrophic reservoir: microscopic counts and DGGE (Denaturing Gradient Gel Electrophoresis)
Willame, Raphael; Boutte, Christophe; Grubisic, Stana ULg et al

in Algological Studies (2009), 129

The seasonal planktic cyanobacterial dynamics was assessed during the year 2000 by microscopic and DGGE techniques, on the basis of 22 samples collected from the Haute-Sûre reservoir (Grand-Duchy of ... [more ▼]

The seasonal planktic cyanobacterial dynamics was assessed during the year 2000 by microscopic and DGGE techniques, on the basis of 22 samples collected from the Haute-Sûre reservoir (Grand-Duchy of Luxembourg). Microscopic investigations were carried out according to the standard Utermöhl procedure while 16S rRNA gene fragments obtained by semi-nested PCR were subsequently separated by DGGE. Sequencing of selected excised bands was performed to genotypically define the cyanobacterial assemblages. The dynamics of cyanobacterial communities obtained by both approaches were compared. Several discordances were pointed out. The counting procedure failed to detect cyanobacteria with small dimensions or in very low abundances, whereas DGGE had a lower detection limit when cyanobacteria were scarce (e.g. in spring) and performed better for the study of picosized forms. Generally, only the dominant cyanobacteria were revealed by these two methods. Actually, both techniques appeared to be complementary rather than equivalent. This study underlines the necessity to use multidisciplinary approaches to obtain a more complete view of the microbial diversity and of the community structure [less ▲]

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See detailMicrobiological and ecological responses to global environmental changes in polar regions (MERGE): An IPY core coordinating project
Naganuma, Takeshi; Wilmotte, Annick ULg

in Polar Sciences (2009), 3

An integrated program, ‘‘Microbiological and ecological responses to global environmental changes in polar regions’’ (MERGE), was proposed in the International Polar Year (IPY) 2007e2008 and endorsed by ... [more ▼]

An integrated program, ‘‘Microbiological and ecological responses to global environmental changes in polar regions’’ (MERGE), was proposed in the International Polar Year (IPY) 2007e2008 and endorsed by the IPY committee as a coordinating proposal. MERGE hosts original proposals to the IPYand facilitates their funding. MERGE selected three key questions to produce scientific achievements. Prokaryotic and eukaryotic organisms in terrestrial, lacustrine, and supraglacial habitats were targeted according to diversity and biogeography; food webs and ecosystem evolution; and linkages between biological, chemical, and physical processes in the supraglacial biome. [less ▲]

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See detailAstrobiologie cours-conférence du Collège Belgique (ARB)
Javaux, Emmanuelle ULg; Wilmotte, Annick ULg; Claeys, Philippe et al

Learning material (2009)

cours enregistrés sur le site de l'ARB (http://www.academieroyale.be/)

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See detailDiversité et limites de la vie
Wilmotte, Annick ULg; Javaux, Emmanuelle ULg

Conference (2009)

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See detailA new approach to analyze genotypes of colony-forming cyanobacteria from environmental samples.
Lara, Yannick ULg; BOUTTE, Christophe; PERETYATKO, Anatoly et al

Poster (2008, August 31)

Several studies have shown the efficiency of sequences as rRNA-ITS, cpcBA, rbcLX and other housekeeping genes to study taxonomy [1, 2, 3], population, community structure of cyanobacteria, or for Multi ... [more ▼]

Several studies have shown the efficiency of sequences as rRNA-ITS, cpcBA, rbcLX and other housekeeping genes to study taxonomy [1, 2, 3], population, community structure of cyanobacteria, or for Multi Locus Sequence Analysis [4]. Recently, the genotypic analysis of single colonies and single filaments directly isolated from the environment has been carried out by other authors. It appears that different genotypes of Microcystis are present in one population in one lake. Besides, succession of toxic and non-toxic genotypes may have a critical influence on toxin concentrations during the blooms [5]. Genotypic analysis of colony-forming cyanobacteria requires enough DNA. So far, the genotypes of environmental single colonies of Microcystis were characterized on the basis of one or two PCR [6]. As the DNA content of one single colony only allows for a few PCR reactions, we have developed a new approach using Whole Genome Amplification with Phi29 polymerase to allow for the Multi Locus Sequences Typing analysis of a single colony or filament. For the first time, we were able to amplify and sequence more than one locus of the genome of a single colony of Microcystis. In addition, we have obtained the first sequences of rpoC1, rbcLX and rRNA-ITS from a single colony of the genus Woronichinia ( identified by microscopy). This approach allows to work with a small amount of DNA, and represents a concrete answer to the lack of data on non-cultivable cyanobacteria. This research is supported by the Belgian Science policy under the science for a sustainable development (SSD) and Fonds de la Recherche Scientifique-FNRS with a FRIA fellowship. References: [1] Otsuka S, et al (1999) FEMS Microbiology Letters 172 15-21 [2] Gugger M, et al (2002) Int J Syst Evol Microbiol 52 1867-1880 [3] Haverkamp T, et al (2008) Environmental Microbiology 10(1) 174-188 [4] Lodders N, et al (2005) Environmental Microbiology 7 (3) 434-442 [5] Kardinaal E, and Visser P (2005) In Harmfuf cyanobacteria, Springer Dordrecht pp 41-64 [6] Janse I, et al (2004) Appl Environm Microbiol 70 (7) 3979–3987 [less ▲]

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