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See detailNovel FISH and quantitative PCR protocols to monitor artificial consortia composed of different hydrogen-producing Clostridium spp.
Savichtcheva, Olga; Joris, Bernard ULg; Wilmotte, Annick ULg et al

in International Journal of Hydrogen Energy (2011), 36

The use of an artificial consortium composed of selected hydrogen-producing species, instead of a natural anaerobic sludge, has been proposed for biohydrogen production. In order to monitor such a ... [more ▼]

The use of an artificial consortium composed of selected hydrogen-producing species, instead of a natural anaerobic sludge, has been proposed for biohydrogen production. In order to monitor such a consortium composed of different Clostridium spp., new protocols were tested for two different assays, FISH and qPCR. New species-specific FISH probes and qPCR primer sets were developed and optimised for three strains: Clostridium butyricum, Clostridium felsineum and Clostridium pasteurianum, that were used in a consortium. Application of a fast two-step FISH protocol, with pre-treatment step at 90 C for 5 min and a subsequent hybridisation step at higher temperature (55 C) for 20 min resulted in a much shorter analytical time compared to the standard FISH procedure (46 C for 2e3 h) and gave a high hybridisation performance. Moreover, to accurately quantify each microorganism by qPCR assay, two innovations were tested: the direct use of cell lysates (omitting the DNA extraction step) and the use of two alternative molecular markers, recA and gyrA. These markers are present in single copies in the genome, whereas there are multiple copies of the ribosomal operons. This resulted in the development of accurate, reliable and fast FISH and qPCR assays for routine monitoring of the dynamics of artificial hydrogen-producing microbial consortia. Moreover, both techniques can be easily adapted to new Clostridium strains. [less ▲]

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See detailA collection of polar cyanobacteria to contribute to the inventory of the biodiversity and discover the biotechnological potential
Wilmotte, Annick ULg; Waleron, Kzryzstof; Waleron, Malgorzata et al

Poster (2011, February)

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See detailAntarctic cyanobacterial diversity: how important are the geographical and ecological factors?
De Carvalho Maalouf, Pedro ULg; Lambion, Alexandre ULg; Gillard, Benjamin et al

Conference (2011, February)

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See detailCYANOBACTERIAL BLOOMS : TOXICITY, DIVERSITY, MODELLING AND MANAGEMENT
Descy, Jean-Pierre; Pirlot, S; Verniers, G et al

Report (2011)

The B-BLOOMS2 project aimed to deepen knowledge of cyanobacterial blooms in Belgium, improve the modelling for prediction and early-warning, develop operational monitoring structures and tools, and ... [more ▼]

The B-BLOOMS2 project aimed to deepen knowledge of cyanobacterial blooms in Belgium, improve the modelling for prediction and early-warning, develop operational monitoring structures and tools, and propose strategies to reduce the impact of cyanobacterial blooms. From a scientific point of view, the research programme focused on: - Collection of physical, chemical, biological and meteorological data on selected reference waterbodies plagued by toxic cyanobacterial blooms in Flanders, Brussels and Wallonia; - Identification and study of the toxigenic cyanobacteria present in the Belgian samples using molecular tools on samples and strains, including genetic diversity and factors regulating their population dynamics; - Measurement of the major cyanotoxins present in the blooms and water samples by analytical methods; - Development and test of management scenarios for control or mitigation of cyanobacterial blooms in one reservoir using integrated watershed models; - Development of a statistical predictive model for a series of urban ponds. From a practical and science policy point of view, B-BLOOMS2 aimed to: - Implement a network of samplers based on existing monitoring programmes of surface waters or on collaboration with health authorities or environmental organisations (BLOOMNET); - Transfer knowledge about methods of monitoring and analysis of blooms to the water/health authorities and environmental organisations by hands-on courses in our laboratories and field sites; - Reinforce the communication to and with authorities and the general population, to raise public awareness, contribute to future guidelines and risk assessment procedures, and improve monitoring and management. [less ▲]

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See detailLow cyanobacterial diversity in biotopes of the Transantarctic Mountains and Shackleton Range (80-82°S), Antarctica.
Fernandez, Rafael; Hodgson, Dominic; Convey, Pete et al

in FEMS Microbiology Ecology (2011), 77

The evolutionary history and geographical isolation of the Antarctic continent have produced a unique environment rich in endemic organisms. In many regions of Antarctica, cyanobacteria are the dominant ... [more ▼]

The evolutionary history and geographical isolation of the Antarctic continent have produced a unique environment rich in endemic organisms. In many regions of Antarctica, cyanobacteria are the dominant phototrophs in both aquatic and terrestrial ecosystems. We have used microscopic and molecular approaches to examine the cyanobacterial diversity of biotopes at two inland continental Antarctic sites (80-82°S). These are amongst the most southerly locations where freshwater-related ecosystems are present. Results showed a low cyanobacterial diversity, with only 3-7 Operational Taxonomic Units (OTUs) per sample obtained by a combination of strain isolations, clone libraries and DGGE based on 16S rRNA genes. One OTU was potentially endemic to Antarctica and is present in several regions of the continent. Four OTUs were shared by the samples from Forlidas Pond and the surrounding terrestrial mats. Only one OTU, but no Internal Transcribed Spacer (ITS) sequences, was common to Forlidas Pond and Lundström Lake. The ITS sequences were shown to further discriminate different genotypes within the OTUs. ITS sequences from Antarctic locations appear more closely related to each other than to non-Antarctic sequences. Future research in inland continental Antarctica will shed more light on the geographical distribution and evolutionary isolation of cyanobacteria in these extreme habitats. [less ▲]

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See detailPlectolyngbya hodgsonii: a novel filamentous cyanobacterium from Antarctic lakes
Taton, Arnaud; Wilmotte, Annick ULg; Smarda, Jan et al

in Polar Biology (2011), 34

A special cluster of filamentous, false-branched cyanobacteria, isolated from littoral mat samples in coastal lakes of the Larsemann Hills region (coll. by D. Hodgson) was studied by a polyphasic approach ... [more ▼]

A special cluster of filamentous, false-branched cyanobacteria, isolated from littoral mat samples in coastal lakes of the Larsemann Hills region (coll. by D. Hodgson) was studied by a polyphasic approach. This morphotype has several characters corresponding to the traditional genera Leptolyngbya (morphology of trichomes), Pseudophormidium (type of false branching) or Schizothrix (occasional multiple arrangement of trichomes in the sheaths). However, this cluster of strains is distinctly isolated according to its phylogenetic position (based on 16S rRNA gene sequences), and thus, a separate generic classification is justified. The cytomorphology of this generic entity is also characteristic. Therefore, a new genus (Plectolyngbya with the type species P. hodgsonii) was described. [less ▲]

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See detailOrgano-mineral imprints in fossil cyanobacterial mats of an Antarctic lake
Javaux, Emmanuelle ULg; Lepot, Kevin ULg; Deremiens, Leo et al

Poster (2010, December)

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See detailPotentiel secondary metabolite biosynthesis operons in environmental colonies of Woronischinia
Lara, Yannick ULg; Lambion, Alexandre ULg; Codd, Goeffrey A. et al

Poster (2010, September 01)

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See detailThe limnology and biology of the Dufek Massif, Transantarctic Mountains 82° South
Hodgson, Dominic A; Convey, Pete; Verleyen, Elie et al

in Polar Science (2010), 4

Very little is known about the higher latitude inland biology of continental Antarctica. In this paper we describe the limnology and biology of the Dufek Massif, using a range of observational ... [more ▼]

Very little is known about the higher latitude inland biology of continental Antarctica. In this paper we describe the limnology and biology of the Dufek Massif, using a range of observational, microscopic and molecular methods. Here two dry valleys are home to some of the southernmost biota on Earth. Cyanobacteria were the dominant life forms, being found in lakes and ponds, in hypersaline brines, summer melt water, relict pond beds and in exposed terrestrial habitats. Their species diversity was the lowest yet observed in Antarctic lakes. Green algae, cercozoa and bacteria were present, but diatoms were absent except for a single valve; likely windblown. Mosses were absent and only one lichen specimen was found. The Metazoa included three microbivorous tardigrades (Acutuncus antarcticus, Diphascon sanae and Echiniscus (cf) pseudowendti) and bdelloid rotifer species, but no arthropods or nematodes. These simple faunal and floral communities are missing most of the elements normally present at lower latitudes in the Antarctic which is probably a result of the very harsh environmental conditions in the area. [less ▲]

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See detailEvidence for widespread endemism among Antarctic micro-organisms
Vyverman, Wim; Verleyen, Elie; Wilmotte, Annick ULg et al

in Polar Science (2010), 4

Understanding the enormous diversity of microbes, their multiple roles in the functioning of ecosystems, and their response to large-scale environmental and climatic changes, are at the forefront of the ... [more ▼]

Understanding the enormous diversity of microbes, their multiple roles in the functioning of ecosystems, and their response to large-scale environmental and climatic changes, are at the forefront of the international research agenda. In Antarctica, where terrestrial and lacustrine environments are predominantly microbial realms, an active and growing community of microbial ecologists is probing this diversity and its role in ecosystem processes. In a broader context, this work has the potential to make a significant contribution to the long-standing debate as to whether microbes are fundamentally different from macroorganisms in their biogeography. According to the ubiquity hypothesis, microbial community composition is not constrained by dispersal limitation and is solely the result of species sorting along environmental gradients. However, recent work on several groups of microalgae is challenging this view. Global analyses using morphology-based diatom inventories have demonstrated that, in addition to environmental harshness, geographical isolation underlies the strong latitudinal gradients in local and regional diversity in the Southern hemisphere. Increasing evidence points to a strong regionalization of diatom floras in the Antarctic and sub- Antarctic regions, mirroring the biogeographical regions that have been recognized for macroorganisms. Likewise, the application of molecular-phylogenetic techniques to cultured and uncultured diversity revealed a high number of Antarctic endemics among cyanobacteria and green algae. Calibration of these phylogenies suggests that several clades have an ancient evolutionary history within the Antarctic continent, possibly dating back to 330 Ma. These findings are in line with the current view on the origin of Antarctic terrestrial metazoa, including springtails, chironomids and mites, with most evidence suggesting a long history of geographic isolation on a multi-million year, even pre-Gondwana break-up timescale [less ▲]

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See detailClotridial hydrogenases and the biohydrogen production
Calusinska, Magdalena ULg; Hamilton, Christopher ULg; Masset, Julien ULg et al

Poster (2010, July 01)

Among the large variety of microorganisms capable of fermentative hydrogen production, strict anaerobes such as Clostridium spp. are one of the most widely studied. They produce hydrogen by butyric and ... [more ▼]

Among the large variety of microorganisms capable of fermentative hydrogen production, strict anaerobes such as Clostridium spp. are one of the most widely studied. They produce hydrogen by butyric and mixed-acid fermentations at optimal pH values ranging from 4.5 to 5.5. While fermentative conditions such as substrate type, pH, hydraulic and solid retention time, H2 partial pressure and the concentration of acids produced have been extensively studied and optimized, relatively little is known about the different forms of hydrogenases present in clostridia. Building on previous reports [1, 2] and by analyzing sequenced genomes, we found that [FeFe] hydrogenases are not a homogenous group of enzymes, but exist in multiple forms with different modular structures and are especially abundant in Clostridum spp. [3]. However, among the numerous studies performed on fermentative hydrogen production by Clostridium sp., only a few are specifically concerned with hydrogenases. Even there the authors focus on one type of [FeFe] hydrogenase, (CpI-like) without considering the existence of multiple forms of this enzyme within one species. Therefore, we focused our research on the better characterization of different forms of hydrogenases present in the genus Clostridium. Using newly designed degenerate primers, specific for clostridial hydrogenases, we amplified different hydrogenases from our species of interest. Further, by designing specific qPCR assays we have quantitatively targeted different hydrogenases. By analyzing differential gene expression, according to applied growth conditions, we believe to optimize the hydrogen production process in order to achieve better production rates. To conclude, we think that a a precise knowledge of hydrogen metabolism and hydrogenases is essential to optimization of the biohydrogen production process and should therefore be a goal for future research. [less ▲]

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See detailB-BLOOMS 2: Importance and diversity of cyanobacterial blooms in Belgium
Wilmotte, Annick ULg

Scientific conference (2010, June 06)

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See detailGenome Sequence of the Edible Cyanobacterium Arthrospira sp. PCC 8005
Janssen, Paul; Morin, Nicolas; Mergeay, Max et al

in Journal of Bacteriology (2010), 192(9), 24652466

We determined the genome sequence of Arthrospira sp. PCC 8005, a cyanobacterial strain of great interest to the European Space Agency for its nutritive value and oxygenic properties in the Micro ... [more ▼]

We determined the genome sequence of Arthrospira sp. PCC 8005, a cyanobacterial strain of great interest to the European Space Agency for its nutritive value and oxygenic properties in the Micro-Ecological Life Support System Alternative (MELiSSA) biological life support system for long-term manned missions into space. [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 surprising diversity of clostridial hydrogenases: a comparative genomic perspective
Calusinska, Magdalena ULg; Happe, Thomas; Joris, Bernard ULg et al

in Microbiology (2010), 156

Among the large variety of micro-organisms capable of fermentative hydrogen production, strict anaerobes such as members of the genus Clostridium are the most widely studied. They can produce hydrogen by ... [more ▼]

Among the large variety of micro-organisms capable of fermentative hydrogen production, strict anaerobes such as members of the genus Clostridium are the most widely studied. They can produce hydrogen by a reversible reduction of protons accumulated during fermentation to dihydrogen, a reaction which is catalysed by hydrogenases. Sequenced genomes provide completely new insights into the diversity of clostridial hydrogenases. Building on previous reports, we found that [FeFe] hydrogenases are not a homogeneous group of enzymes, but exist in multiple forms with different modular structures and are especially abundant in members of the genus Clostridium. This unusual diversity seems to support the central role of hydrogenases in cell metabolism. In particular, the presence of multiple putative operons encoding multisubunit [FeFe] hydrogenases highlights the fact that hydrogen metabolism is very complex in this genus. In contrast with [FeFe] hydrogenases, their [NiFe] hydrogenase counterparts, widely represented in other bacteria and archaea, are found in only a few clostridial species. Surprisingly, a heteromultimeric Ech hydrogenase, known to be an energy-converting [NiFe] hydrogenase and previously described only in methanogenic archaea and some sulfur-reducing bacteria, was found to be encoded by the genomes of four cellulolytic strains: Clostridum cellulolyticum, Clostridum papyrosolvens, Clostridum thermocellum and Clostridum phytofermentans [less ▲]

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See detailBiogeography of terrestrial cyanobacteria from Antarctic ice-free areas
Namsaraev, Zorigto ULg; Mano, Marie-José ULg; Fernandez Carazo, Rafael ULg et al

in Annals of Glaciology (2010), 51(56), 171-177

Cyanobacteria inhabit the Antarctic continent and have even been observed in the most southerly ice-free areas of Antarctica (86–878 S). The highest molecular diversity of cyanobacterial communities was ... [more ▼]

Cyanobacteria inhabit the Antarctic continent and have even been observed in the most southerly ice-free areas of Antarctica (86–878 S). The highest molecular diversity of cyanobacterial communities was found in the areas located between 708 S and 808 S. Further south and further north from this zone, the diversity abruptly decreased. Seventy-nine per cent (33 of 42 operational taxonomic units) of Antarctic terrestrial cyanobacteria have a cosmopolitan distribution. Analysis of the sampling efforts shows that only three regions (southern Victoria Land, the Sør Rondane Mountains and Alexander Island) have been particularly well studied, while other areas did not receive enough attention. Although cyanobacteria possess a capacity for long-range transport, regional populations in Antarctic ice-free areas seem to exist. The cyanobacterial communities of the three most intensively studied regions, separated from each other by a distance of 3000–3400 km, had a low degree of similarity with each other. Further development of microbial biogeography demands a standardized approach. For this purpose, as a minimal standard, we suggest using the sequence of cyanobacterial 16S rRNA gene between Escherichia coli positions 405–780. [less ▲]

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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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