WorldCat Identities

López-Garcìa, Purificación

Overview
Works: 23 works in 50 publications in 3 languages and 342 library holdings
Genres: History 
Roles: Editor, Opponent, Thesis advisor, 958, Author, Commentator, Interviewee, 956
Publication Timeline
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Most widely held works by Purificación López-Garcìa
Origins and evolution of life : an astrobiological perspective by Muriel Gargaud( Book )

12 editions published between 2010 and 2011 in English and held by 268 WorldCat member libraries worldwide

"Devoted to exploring questions about the origin and evolution of life in our Universe, this highly interdisciplinary book brings together a broad array of scientists. Thirty chapters assembled in eight major sections convey the knowledge accumulated and the richness of the debates generated by this challenging theme. The text explores the latest research on the conditions and processes that led to the emergence of life on Earth and, by extension, perhaps on other planetary bodies. Diverse sources of knowledge are integrated, from astronomical and geophysical data, to the role of water, the origin of minimal life properties and the oldest traces of biological activity on our planet. This text will not only appeal to graduate students but to the large body of scientists interested in the challenges presented by the origin of life, its evolution, and its possible existence beyond Earth"--
From suns to life : a chronological approach to the history of life on earth by Muriel Gargaud( )

6 editions published in 2006 in English and held by 23 WorldCat member libraries worldwide

This review emerged from several interdisciplinary meetings and schools gathering a group of astronomers, geologists, biologists, and chemists, attempting to share their specialized knowledge around a common question: how did life emerge on Earth? Their ultimate goal was to provide some kind of answer as a prerequisite to an even more demanding question: is life universal? The resulting state-of-the-art articles were written by twenty-five scientists telling a not-so linear story, but on the contrary, highlighting problems, gaps, and controversies. Needless to say, this approach yielded no definitive answers to both questions. However, by adopting a chronological approach to the question of the emergence of life on Earth, the only place where we know for sure that life exists; it was possible to break down this question into several sub-topics that can be addressed by the different disciplines. The main chapters of this review present the formation and evolution of the solar system (3); the building of a habitable planet (4); prebiotic chemistry, biochemistry, and the emergence of life (5); the environmental context of the early Earth (6); and the ancient fossil record and early evolution (7). The concluding chapter (9) provides the highlights of the review and presents the different points of view about the universality of life. Two pedagogical chapters are included; one on chronometers (2), another in the form of a "frieze" (8) which summarizes in graphical form the present state of knowledge about the chronology of the emergence of life on Earth, before the Cambrian explosion
Le Soleil, la Terre ... la vie la quête des origines by Muriel Gargaud( Book )

5 editions published in 2012 in English and held by 17 WorldCat member libraries worldwide

How did the Sun come into existence? How was the Earth formed? How long has Earth been the way it is now, with its combination of oceans and continents? How do you define "life"? How did the first life forms emerge? What conditions made it possible for living things to evolve? All these questions are answered in this colourful textbook addressing undergraduate students in "Origins of Life" courses and the scientifically interested public. The authors take the reader on an amazing voyage through time, beginning five thousand million years ago in a cloud of interstellar dust and ending five hundred million years ago, when the living world that we see today was finally formed. A chapter on exoplanets provides an overview of the search for planets outside the solar system, especially for habitable ones. The appendix closes the book with a glossary, a bibliography of further readings and a summary of the Origins of the Earth and life in fourteen boxes -- P. 4 of cover
Origins and Evolution of Life( )

2 editions published in 2010 in English and held by 5 WorldCat member libraries worldwide

La vie dans des conditions extrêmes( Visual )

3 editions published between 2003 and 2004 in French and held by 4 WorldCat member libraries worldwide

Apuntes de microbiologia médica según las explicaciones del Prof. Ruiz Falcó by L. G Urgoiti( Book )

4 editions published between 1932 and 1933 in Spanish and held by 3 WorldCat member libraries worldwide

Dynamique temporelle des communautés microbiennes eucaryotes en lien avec les forçages climatiques et anthropiques : approche paléolimnologique basée sur le séquençage massif d'ADN sédimentaire by Éric Capo( )

1 edition published in 2016 in French and held by 3 WorldCat member libraries worldwide

L'eutrophisation et le réchauffement climatique sont reconnus comme des forçages majeurs du fonctionnement des lacs. Toutefois les connaissances concernant la réponse des communautés microbiennes eucaryotes à ces forçages sont encore très lacunaires, alors même que les microbes eucaryotes, porteurs d'une vaste diversité taxonomique et fonctionnelle, sont des acteurs clés des réseaux trophiques lacustres. La pertinence des approches paléolimnologiques pour comprendre les impacts de ces forçages sur les communautés lacustres n'est plus à démontrer, mais aujourd'hui l'intégration des outils moléculaires pour analyser l'ADN archivé dans les sédiments offre des opportunités nouvelles pour reconstituer la dynamique passée de la biodiversité lacustre. Dans ce cadre, en s'appuyant sur le couplage entre paléolimnologie et outils de séquençage massif appliqués à l'ADN sédimentaire, ces travaux ont pour but (i) d'apporter des connaissances concernant la préservation de l'ADN des microbes eucaryotes dans les sédiments lacustres (ii) d'appliquer l'approche de paléogénétique sur des carottes sédimentaires issues de 3 lacs pour révéler la dynamique à long terme (de la décennie au millénaire) des microbes eucaryotes en lien avec l'évolution des conditions climatiques et anthropiques. Les résultats acquis sur le lac du Bourget ont permis de mettre en évidence l'efficacité d'archivage de l'ADN planctonique dans les sédiments récents pour la plupart des groupes eucaryotes (notamment chrysophycées, chytrides, chlorophytes, cercozoaires, ciliés, dinophycées). A partir d'une collection de carottes (issues du lac suédois Nylandssjön), l'effet de la diagénèse s'opérant au cours des premières années d'enfouissement a été évalué, permettant de démontrer que si la richesse taxonomique n'est pas impactée, des variations peuvent être détectées dans la structure de la communauté au cours des 10 premières années d'archivage avec une stabilisation du signal au-delà de cette période. L'approche paléogénétique a, en parallèle, été déployée d'une part à l'échelle du siècle sur deux lacs de même typologie mais ayant subi des niveaux d'eutrophisation contrastés, et d'autre part à une échelle temporelle plus longue (2200 ans) pour deux lacs de typologie contrastée (lac du Bourget, France et Igaliku, Groenland). Les résultats acquis démontrent que des réarrangements des communautés s'opèrent de manière concomitante aux périodes climatiques (réchauffement médiéval, petit âge glaciaire, réchauffement récent), et que le réchauffement climatique au cours des 30 dernières années a plus particulièrement favorisé certains groupes, notamment la richesse et l'abondance des dinophycées (en condition non eutrophe ; lac d'Annecy et du Bourget). Toutefois l'effet de l'eutrophisation est identifié comme le facteur le plus structurant, notamment dans le lac du Bourget (cas d'eutrophisation marquée, ~120 µgP.L-1). La forte influence du niveau d'eutrophisation est détectée sur la communauté eucaryote totale et plus particulièrement sur des groupes spécifiques tels que les chlorophytes et les ciliés. Les réarrangements majeurs de la communauté sont par ailleurs marqués par la mobilisation de taxons rares dans l'assemblage microbien eucaryote suggérant le rôle de la biosphère rare dans la capacité tampon des écosystèmes. Ces travaux pluridisciplinaires comptent parmi les premières études paléogénétiques appliquées aux microbes eucaryotes lacustres, contribuant de manière inédite aux connaissances de leur dynamique temporelle à long terme. Ces études tendent à confirmer le potentiel de ces approches pour reconstituer une vaste diversité de communautés lacustres. Les perspectives qui se dessinent dans la continuité de ces travaux concernent à la fois des aspects méthodologiques autour de la calibration du signal ADN archivé et la nécessité de déployer cette approche pour des lacs (sélectionnés) de typologies et histoires écologiques variées
ʺDeciphering archaeal communitiesʺ omics tools in the study of archaeal communities by Lejla Pašić( )

1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide

Unexpected diversity of small eukaryotes in deep-sea Antarctic plankton by Purificación López-Garcìa( )

1 edition published in 2001 in English and held by 2 WorldCat member libraries worldwide

Géomicrobiologie des microbialites du lac Alcalin d'Alchichica (Mexique) by Estelle Couradeau( Book )

2 editions published in 2012 in French and held by 2 WorldCat member libraries worldwide

Les stromatolites sont des structures organo-sédimentaires formées grâce à l'activité des microorganismes. Ils dominent le registre fossile Précambrien et sont parmi les plus anciennes traces potentielles de vie sur Terre, Cependant les processus biotiques et abiotiques à l'origine de leur formation restent peu compris. L'objectif central de ce travail est de contribuer à améliorer notre compréhension de la formation des microbialites modernes, afin de mieux contraindre l'interprétation du registre fossile des stromatolites. Nous avons étudié le système modèle des microbialites modernes du lac alcalin d'Alchichica (Mexique). La première partie de ce travail est dédiée à la description générale des microorganismes et des minéraux du système. Les résultats obtenus nous ont permis de construire un modèle hypothétique des réactions métabolico-géochimiques contribuant à la précipitation ou dissolution des carbonates dans les biofilms des microbialites d'Alchichica. Dans la seconde partie de ce travail, nous avons décrit un gradient de fossilisation de colonies de cyanobactéries de l'ordre des Pleurocapsales dans l'aragonite. Cette étude ouvre des perspectives dans la recherche de microfossiles de cyanobactéries dans les stromatolites fossiles. La troisième partie rapporte la découverte d'un cas de biominéralisation intracellulaire contrôlée chez une cyanobactérie de l'ordre basai des Gloeobacterales. La souche Candidatus Gloeomargarita lithophora produit des inclusions intracellulaires de carbonates de Ba-Sr-Ca-Mg. Les implications de la découverte de ce nouveau patron de minéralisation chez les cyanobactéries pour l'interprétation du registre fossile ancien sont discutées
From Suns to Life by Muriel Gargaud( )

1 edition published in 2006 in English and held by 1 WorldCat member library worldwide

Symbiosis in eukaryotic evolution( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

Abstract: Fifty years ago, Lynn Margulis, inspiring in early twentieth-century ideas that put forward a symbiotic origin for some eukaryotic organelles, proposed a unified theory for the origin of the eukaryotic cell based on symbiosis as evolutionary mechanism. Margulis was profoundly aware of the importance of symbiosis in the natural microbial world and anticipated the evolutionary significance that integrated cooperative interactions might have as mechanism to increase cellular complexity. Today, we have started fully appreciating the vast extent of microbial diversity and the importance of syntrophic metabolic cooperation in natural ecosystems, especially in sediments and microbial mats. Also, not only the symbiogenetic origin of mitochondria and chloroplasts has been clearly demonstrated, but improvement in phylogenomic methods combined with recent discoveries of archaeal lineages more closely related to eukaryotes further support the symbiogenetic origin of the eukaryotic cell. Margulis left us in legacy the idea of 'eukaryogenesis by symbiogenesis'. Although this has been largely verified, when, where, and specifically how eukaryotic cells evolved are yet unclear. Here, we shortly review current knowledge about symbiotic interactions in the microbial world and their evolutionary impact, the status of eukaryogenetic models and the current challenges and perspectives ahead to reconstruct the evolutionary path to eukaryotes. Graphical abstract: Molecular phylogeny, comparative genomics and the exploration of microbial diversity and interactions in the environment converge to support the symbiotic origin of the eukaryotic cell. The first eukaryotes arose by symbiosis of one archaeon and one or several bacteria along a non-fully-elucidated process. Eukaryotic photosynthesis arose by the endosymbiosis of a cyanobacterium in a heterotrophic host and subsequently spread to other eukaryotes via secondary algal endosymbioses. Highlights: 50 years ago, Margulis proposed a theory for the origin of eukaryotes by symbiosis. The symbiogenetic origin of mitochondria and chloroplasts was soon demonstrated. Recent discoveries of new archaea also support a symbiogenetic origin of eukaryotes. Symbiosis is widespread in nature and has a profound impact on microbial evolution. Eukaryogenesis occurred by symbiogenesis but where, how and when are yet unclear
Phylogénie, diversité et dynamique temporelle chez les ciliés tintinnidés marins by Charles Bachy( )

1 edition published in 2012 in French and held by 1 WorldCat member library worldwide

The marine protistan diversity has been historically studied based on morphological characterization but has recently been the object of intense research using molecular approaches. Studies based on the amplification of molecular markers from environmental DNA revealed an outstanding diversity, partly new and uncharacterized. However, the actual extent of this diversity remains poorly known and highly debated. The main goal of this work was to improve our knowledge on protistan diversity to bridge the gap between molecular environmental surveys and classical protistology to better understand the ecology and evolution of unicellular eukaryotes. For this purpose, we used as a model the species-rich order of the tintinnid ciliates (Tintinnida, Ciliophora), which are easily distinguishable because of their secreted shell, the lorica, and commonly found in marine waters all around the globe. A two-year monitoring of the tintinnid populations in the Bay of Villefranche-sur- Mer (Mediterranean Sea, France), combining molecular analyses of the diversity based on single-cells and environmental DNA, gave us the opportunity to describe the tintinnid community composition and its temporal dynamics. In the first part of this work, we constructed a reference molecular phylogeny for the tintinnids including new sequences from 62 specimens of diverse morphologies, for which we amplified and sequenced the ribosomal coding genes (18S, 5.8S and 28S rRNA) and the corresponding intergenic spacers (ITS1 and ITS2). The taxonomic classification of the Tintinnida has been revised based on these molecular data. In the second part, in order to assess the accuracy of molecular-based approaches to describe the natural species assemblages of tintinnids, we compared the morphology-based diversity estimates with those derived from classical (amplification, cloning and Sanger sequencing of the 18S rRNA gene) and more recent (direct pyrosequencing of amplified 18S rRNA genes and ITS regions) molecular approaches. Even if there are still some disagreements between the different methods and/or molecular markers, the culture-independent approaches were efficient to describe the morphological diversity. However, a careful and rigorous analysis of pyrosequencing datasets, including sequence denoising and stringent sequence clustering in Operational Taxonomic Units (OTUs) with well-adjusted parameters, is necessary to avoid overestimating the species number. The third part of the thesis is dedicated to the study of the genetic diversity of tintinnids over a one-year survey in the Bay of Villefranche at five different depths by combining community fingerprinting analysis using denaturing gradient gel electrophoresis (DGGE) with direct PCR amplification and sequencing of 18S, 5.8S, and 28S rRNA genes and ITS regions. These analyses revealed marked seasonal changes, in particular in the sequence abundances of certain OTUs. In addition, despite an enriched phylogenetic reference sequence dataset for the tintinnids, we retrieved two abundant phylotypes without any closely related known species, highlighting the possible ecological relevance of unidentified species. Finally, we studied the intra-specific diversity of populations of the species <Undella claparedei> based on 18S rDNA and ITS direct sequencing of single-cells collected over a period of two years. We detected signals of hybridization and sexual recombination among different genetic variants. We also found genetic structuring of the 18S rRNA gene data differentiating populations collected at different times. The implications of all these results are discussed in the framework of the diversity and ecology of tintinnid ciliates and, more generally, of marine protists
Dallol aux frontières de la vie( Visual )

1 edition published in 2016 in French and held by 1 WorldCat member library worldwide

Culture-independent methods and high-throughput sequencing applied to evolutionary microbial genomics by Anders E Lind( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

Culture-independent methods allow us to better understand the diversity of microorganisms on earth. By omitting the culturing step, we can gain access to species previously out of our reach. To better capture and understand the diversity of microorganisms, we have developed an alternative to 16S amplicon sequencing. This method exploits the fact that the rRNA operon in most prokaryotes contains both the 16S and the 23S genes in a determined order, close to each other. Combining this with PacBio long molecule sequencing, we can now generate amplicon containing the 16S-ITS-23S operon, allowing for a stronger phylogenetic signal. Using two culture-independent methods, single-cell genomics and metagenomics, we have been able to fully sequence the genome of two archaeal endosymbionts from the genera Methanobrevibacter and Methanocorpusculum . These methanogenic archaea were isolated from the ciliates Nyctotherus ovalis and Metopus contortus . The genomic data show evidence of genome degradation, mainly through pseudogenization of genes. These genomes represent the first genomic data from archaeal endosymbionts. The endosymbiotic archaea we have sequenced live in close proximity to hydrogen producing mitochondria, or hydrogenosomes. In ciliates it has previously been shown that the hydrogenosome of N. ovalis has retained a genome, something many other ciliate hydrogenosome have not. Using genomic and transcriptomic data from seven anaerobic ciliates, we have been able to show that these ciliate have independently evolved from ancestral mitochondria, and show various degrees of genome reduction. Furthermore we have been able to shed some new light on haloarchaeal evolution by reconstructing the genomes of five species belonging to the Marine Group IV archaea. These archaea have previously been found to be closely related to the haloarchaea, however they are not halophiles. All five genomes were obtained using metagenomic binning of the publicly available TARA Oceans dataset. The genomes are all of high quality and completeness, and are used in tree-aware ancestral reconstruction, in order to try to better understand the evolutionary transition from an anaerobic methanogen to a halophile. These studies all show how culture-independent method are powerful tools in gathering genomic information about microbes we are currently unable to culture in the lab
Structure et activité des Archaea planctoniques dans les écosystèmes aquatiques by Mylène Hugoni( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

Aquatic Archaea are important players among microbial plankton and significantly contribute to biogeochemical cycles, especially nitrogen, but details regarding their community structure and seasonal activity and dynamics remain largely unexplored. In marine ecosystems, the widespread distribution of Ammonia Oxidizing Archaea (AOA) suggests that they probably play a major role in nutrients cycling. However, we cannot generalize these observations to all aquatic ecosystems because of their high diversity and/or a lack of information and studies on these organisms for some of these ecosystems. More precisely, lacustrine and coastal ecosystems were less studied while they are potentially subjected to strong anthropogenic impacts. Moreover, notable differences in terms of diversity and activity between marine and freshwater communities can be expected, considering the specific environmental parameters of each ecosystem. The objectives of this thesis were: i) to study the archaeal community structure across a temporal scale and assess the diversity of archaeal communities and AOA in diverse aquatic ecosystems along anthropogenic and/or salinity gradient (lacustrine, estuarine and coastal ecosystems); ii) to determine their relative contribution in ammonia oxidation, compared to Ammonia Oxidizing Bacteria (AOB) by looking at their spatial and temporal distribution and activity, and iii) to explore more precisely the environmental parameters that could drive AOA and/or AOB establishment
Parvularia atlantis gen. et sp. nov., a Nucleariid Filose Amoeba (Holomycota, Opisthokonta)( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

Abstract: The opisthokonts constitute a eukaryotic supergroup divided into two main clades: the holozoans, which include animals and their unicellular relatives, and the holomycotans, which include fungi, opisthosporidians, and nucleariids. Nucleariids are phagotrophic filose amoebae that phenotypically resemble more their distant holozoan cousins than their holomycotan phylogenetic relatives. Despite their evolutionary interest, the diversity and internal phylogenetic relationships within the nucleariids remain poorly studied. Here, we formally describe and characterize by molecular phylogeny and microscopy observations Parvularia atlantis gen. et sp. nov. (formerly Nuclearia sp. ATCC 50694), and compare its features with those of other nucleariid genera. Parvularia is an amoebal genus characterized by radiating knobbed and branching filopodia. It exhibits prominent vacuoles observable under light microscopy, a cyst‐like stage, and completely lacks cilia. P.atlantis possesses one or two nuclei with a central nucleolus, and mitochondria with flat or discoid cristae. These morphological features, although typical of nucleariids, represent a combination of characters different to those of any other described Nuclearia species. Likewise, 18S rRNA‐based phylogenetic analyses show that P.atlantis represents a distinct lineage within the nucleariids
The place of viruses in biology in light of the metabolism-versus-replication-first debate by Purificación López-Garcìa( Book )

1 edition published in 2012 in English and held by 1 WorldCat member library worldwide

Diversité, distribution spatiale et dynamique temporelle des petits eucaryotes dans des écosystèmes d'eau douce peu profond by Marianne Simon( )

1 edition published in 2014 in French and held by 1 WorldCat member library worldwide

The diversity of very small eukaryotes (<5 µm) has mainly been studied by molecular methods in marine systems or in large lakes. However, that of small shallow systems remains practically unexplored, despite the fact that these systems are extensive and ecologically important in temperate regions. We thus aimed at describing the diversity and community composition of small eukaryotes in shallow freshwater systems, using molecular methods targeting the 18S rRNA gene of planktonic cells in the 0.2-5 µm size range. We first focused on haptophytes, an important group in marine environments but much less known in freshwaters. We explored their diversity using newly designed specific primers to amplify haptophyte 18S rRNA genes, followed by their subsequent cloning and Sanger sequencing in seventeen continental ecosystems and in two marine water columns to allow comparisons between different environments, as well as using 454-pyrosequencing in 4 ponds and one brook during a 2-years monthly survey. Even if freshwater haptophytes were less diverse than marine lineages, we revealed the presence of a divergent lineage belonging to the Isochrysidales never recorded so far, which presented a marked seasonality. Freshwater phylotypes were usually distinct from their marine counterparts, and confirmed the occurrence of multiple marine-freshwater transitions in haptophyte evolution. In a second step, we explored the microbial eukaryote diversity in 5 distinct shallow ecosystems sampled at spring and that differ in size, shape and surrounding environment, by 454-pyrosequencing their 18S rDNA. Diversity was high in the studied systems, with sequences affiliated to the 7 recognized eukaryotic supergroups (Archaeplastida, Stramenopiles, Alveolata, Rhizaria, Excavata, Amoebozoa and Opisthokonta) as well as groups of unresolved phylogenetic position including, among others, Cryptophyta, Haptophyta, Centroheliozoa or Katablepharida. Especially, we detected OTUs affiliated to the previously thought exclusively marine lineage MAST-3 (MArine STramenopiles), and potentially to other MAST groups with no known representative from freshwaters. Small eukaryote community structures were different in the five ecosystems. Differences in community compositions did not correlate with geographical distances (Mantel test), and multivariate statistical analyses did not reveal clear relationships between any group distribution and specific environmental parameters. Then, we conducted a 2-years survey of eukaryotic micro-organisms diversity in the same 5 small ecosystems. To do so, we collected plankton and measured several physical and chemical parameters on a monthly basis, except for two systems when they were totally dry. The total diversity encountered during the 24 months was much broader than that identified in the previous snapshot study. The most abundant detected groups were Cryptophytes, Ciliates, Chrysophytes and Fungi sensu stricto. Community structures and compositions were different in the five systems along the two years. In all systems, communities were highly dynamic, and revealed a marked seasonality, notably with summer and winter communities being always distinct. Multivariate statistical analyses were used to analyze simultaneously physico-chemical data and community compositions. The clearest correlation associated fungi distribution and high conductivity. Finally, we described the dynamics of small-eukaryote communities in a pond and a brook through drought events. We collected sediment on the system beds when they were dry, and plankton the rest of time. Communities in the sediment and in the water presented distinct signatures. Surface water communities presented (a high) resilience, and recovered a planktonic signature within a month after the systems were filled up again with water
Diversité et processus de colonisation microbienne sur des substrats minéraux by Marie Ragon( )

1 edition published in 2011 in French and held by 1 WorldCat member library worldwide

The major objective of my PhD work was the analysis of the diversity of microorganisms from the three domains of life associated with phototrophic biofilms developing on different mineral substrates exposed outdoors. These studies aimed at answering questions about microbial diversity and biogeography and also at studying the colonization process through controlled exposure experiments. I have thus characterized, essentially by molecular methods based on small subunit (SSU) rRNA gene libraries and fingerprinting analyses the diversity of prokaryote and eukaryote microorganisms forming mature biofilms (exposed for several years) in various geographic sites in Northern Ireland, France and Ukraine, in the Chernobyl area. In these biofilms, subjected to strong selective pressure, we found many heterotrophic and phototrophic microorganisms, but their diversity was limited when compared to that of other environments such as soils or aquatic systems. Archaea were absent from all biofilms. The environmental conditions to which these biofilms are constantly exposed, such as irradiation, desiccation and nutrient limitation select for organisms that develop particular adaptive strategies including, among others, pigment production. The microorganisms identified in these biofilms are also frequently found in extreme, desert environments and are known for their resistance also to ionizing radiation, such as Deinococcales and Actinobacteria or ascomycete fungi (Ascomycota). Among phototrophic lineages, we identified Cyanobacteria, Chlorophyta (green algae) and sometimes Streptophyta. We showed that environmental parameters influenced biofilm microbial communities. However, whereas the bacterial community composition depends on the nature of the substrate, the microbial eukaryotic community composition depends on the geographic distance. We also carried out colonization experiences exposing outdoors the same mineral substrate in three different sites in Northern Ireland and France. The analysis of microbial diversity along the colonization process revealed important changes in community composition both for prokaryotes and eukaryotes, although the behavior of the two groups was different. In the case of bacteria, we observed a transition from Gammaproteobacteria, which dominated the initial 0-6 months and which likely corresponded to inactive dispersive cells, towards Betaproteobacteria, Bacteroidetes, Alphaproteobacteria and Actinobacteria in successive steps of biofilm formation. By contrast, since their detection on mineral substrates, eukaryotes were massively dominated by ascomycete and basidiomycete fungi, green algae and other minor components such as ciliates were detected in later stages of biofilm formation. Our results show that heterotrophic organisms are pioneers in the formation of these biofilms, leading to the hypothesis that they facilitate the settlement of Cyanobacteria and, especially, of green algae. They also show that the process of bacteria community assembly depends on colonization time whereas the geographic site determines that of eukaryotic microorganisms. These major differences might be explained by different lifestyles between organisms of the two groups
 
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Origins and evolution of life : an astrobiological perspective
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From suns to life : a chronological approach to the history of life on earthFrom Suns to Life
Alternative Names
García, Purificación López-.

López-García, P.

Purificación Lopez-Garcia microbiologiste

Languages
English (32)

French (11)

Spanish (4)