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Author

Chantal Abergel

Bio: Chantal Abergel is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Giant Virus & Mimivirus. The author has an hindex of 41, co-authored 129 publications receiving 8765 citations. Previous affiliations of Chantal Abergel include IGS Energy & National Institutes of Health.
Topics: Giant Virus, Mimivirus, Genome, Mimiviridae, Gene


Papers
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Journal ArticleDOI
19 Nov 2004-Science
TL;DR: The size and complexity of the Mimivirus genome challenge the established frontier between viruses and parasitic cellular organisms and this new sequence data might help shed a new light on the origin of DNA viruses and their role in the early evolution of eukaryotes.
Abstract: We recently reported the discovery and preliminary characterization of Mimivirus, the largest known virus, with a 400-nanometer particle size comparable to mycoplasma. Mimivirus is a double-stranded DNA virus growing in amoebae. We now present its 1,181,404–base pair genome sequence, consisting of 1262 putative open reading frames, 10% of which exhibit a similarity to proteins of known functions. In addition to exceptional genome size, Mimivirus exhibits many features that distinguish it from other nucleocytoplasmic large DNA viruses. The most unexpected is the presence of numerous genes encoding central protein-translation components, including four amino-acyl transfer RNA synthetases, peptide release factor 1, translation elongation factor EF-TU, and translation initiation factor 1. The genome also exhibits six tRNAs. Other notable features include the presence of both type I and type II topoisomerases, components of all DNA repair pathways, many polysaccharide synthesis enzymes, and one intein-containing gene. The size and complexity of the Mimivirus genome challenge the established frontier between viruses and parasitic cellular organisms. This new sequence data might help shed a new light on the origin of DNA viruses and their role in the early evolution of eukaryotes.

927 citations

Journal ArticleDOI
M. Marvin Seibert1, Tomas Ekeberg1, Filipe R. N. C. Maia1, Martin Svenda1, Jakob Andreasson1, Olof Jönsson1, Dusko Odic1, Bianca Iwan1, Andrea Rocker1, Daniel Westphal1, Max F. Hantke1, Daniel P. DePonte, Anton Barty, Joachim Schulz, Lars Gumprecht, Nicola Coppola, Andrew Aquila, Mengning Liang, Thomas A. White, Andrew V. Martin, Carl Caleman1, Stephan Stern2, Chantal Abergel3, Virginie Seltzer3, Jean-Michel Claverie3, Christoph Bostedt4, John D. Bozek4, Sébastien Boutet4, A. Miahnahri4, Marc Messerschmidt4, Jacek Krzywinski4, Garth J. Williams4, Keith O. Hodgson4, Michael J. Bogan4, Christina Y. Hampton4, Raymond G. Sierra4, D. Starodub4, Inger Andersson5, Sǎa Bajt, Miriam Barthelmess, John C. H. Spence6, Petra Fromme6, Uwe Weierstall6, Richard A. Kirian6, Mark S. Hunter6, R. Bruce Doak6, Stefano Marchesini7, Stefan P. Hau-Riege8, Matthias Frank8, Robert L. Shoeman9, Lukas Lomb9, Sascha W. Epp9, Robert Hartmann, Daniel Rolles9, Artem Rudenko9, Carlo Schmidt9, Lutz Foucar9, Nils Kimmel9, Peter Holl, Benedikt Rudek9, Benjamin Erk9, André Hömke9, Christian Reich, Daniel Pietschner9, Georg Weidenspointner9, Lothar Strüder9, Günter Hauser9, H. Gorke, Joachim Ullrich9, Ilme Schlichting9, Sven Herrmann9, Gerhard Schaller9, Florian Schopper9, Heike Soltau, Kai Uwe Kuhnel9, Robert Andritschke9, Claus Dieter Schröter9, Faton Krasniqi9, Mario Bott9, Sebastian Schorb10, Daniela Rupp10, M. Adolph10, Tais Gorkhover10, Helmut Hirsemann, Guillaume Potdevin, Heinz Graafsma, Björn Nilsson, Henry N. Chapman2, Janos Hajdu1 
03 Feb 2011-Nature
TL;DR: This work shows that high-quality diffraction data can be obtained with a single X-ray pulse from a non-crystalline biological sample, a single mimivirus particle, which was injected into the pulsed beam of a hard-X-ray free-electron laser, the Linac Coherent Light Source.
Abstract: The start-up of the Linac Coherent Light Source (LCLS), the new femtosecond hard X-ray laser facility in Stanford, California, has brought high expectations of a new era for biological imaging. The intense, ultrashort X-ray pulses allow diffraction imaging of small structures before radiation damage occurs. Two papers in this issue of Nature present proof-of-concept experiments showing the LCLS in action. Chapman et al. tackle structure determination from nanocrystals of macromolecules that cannot be grown in large crystals. They obtain more than three million diffraction patterns from a stream of nanocrystals of the membrane protein photosystem I, and assemble a three-dimensional data set for this protein. Seibert et al. obtain images of a non-crystalline biological sample, mimivirus, by injecting a beam of cooled mimivirus particles into the X-ray beam. The start-up of the new femtosecond hard X-ray laser facility in Stanford, the Linac Coherent Light Source, has brought high expectations for a new era for biological imaging. The intense, ultrashort X-ray pulses allow diffraction imaging of small structures before radiation damage occurs. This new capability is tested for the problem of imaging a non-crystalline biological sample. Images of mimivirus are obtained, the largest known virus with a total diameter of about 0.75 micrometres, by injecting a beam of cooled mimivirus particles into the X-ray beam. The measurements indicate no damage during imaging and prove the concept of this imaging technique. X-ray lasers offer new capabilities in understanding the structure of biological systems, complex materials and matter under extreme conditions1,2,3,4. Very short and extremely bright, coherent X-ray pulses can be used to outrun key damage processes and obtain a single diffraction pattern from a large macromolecule, a virus or a cell before the sample explodes and turns into plasma1. The continuous diffraction pattern of non-crystalline objects permits oversampling and direct phase retrieval2. Here we show that high-quality diffraction data can be obtained with a single X-ray pulse from a non-crystalline biological sample, a single mimivirus particle, which was injected into the pulsed beam of a hard-X-ray free-electron laser, the Linac Coherent Light Source5. Calculations indicate that the energy deposited into the virus by the pulse heated the particle to over 100,000 K after the pulse had left the sample. The reconstructed exit wavefront (image) yielded 32-nm full-period resolution in a single exposure and showed no measurable damage. The reconstruction indicates inhomogeneous arrangement of dense material inside the virion. We expect that significantly higher resolutions will be achieved in such experiments with shorter and brighter photon pulses focused to a smaller area. The resolution in such experiments can be further extended for samples available in multiple identical copies.

838 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used a comparative genomic approach to identify the complete repertoire of resistance genes exhibited by the multidrug-resistant A. baumannii strain AYE, which is epidemic in France, as well as investigate the mechanisms of their acquisition by comparison with the fully susceptible A. bayannii species SDF, associated with human body lice.
Abstract: Acinetobacter baumannii is a species of nonfermentative gram-negative bacteria commonly found in water and soil. This organism was susceptible to most antibiotics in the 1970s. It has now become a major cause of hospital-acquired infections worldwide due to its remarkable propensity to rapidly acquire resistance determinants to a wide range of antibacterial agents. Here we use a comparative genomic approach to identify the complete repertoire of resistance genes exhibited by the multidrug-resistant A. baumannii strain AYE, which is epidemic in France, as well as to investigate the mechanisms of their acquisition by comparison with the fully susceptible A. baumannii strain SDF, which is associated with human body lice. The assembly of the whole shotgun genome sequences of the strains AYE and SDF gave an estimated size of 3.9 and 3.2 Mb, respectively. A. baumannii strain AYE exhibits an 86-kb genomic region termed a resistance island—the largest identified to date—in which 45 resistance genes are clustered. At the homologous location, the SDF strain exhibits a 20 kb-genomic island flanked by transposases but devoid of resistance markers. Such a switching genomic structure might be a hotspot that could explain the rapid acquisition of resistance markers under antimicrobial pressure. Sequence similarity and phylogenetic analyses confirm that most of the resistance genes found in the A. baumannii strain AYE have been recently acquired from bacteria of the genera Pseudomonas, Salmonella, or Escherichia. This study also resulted in the discovery of 19 new putative resistance genes. Whole-genome sequencing appears to be a fast and efficient approach to the exhaustive identification of resistance genes in epidemic infectious agents of clinical significance.

757 citations

Journal ArticleDOI
19 Jul 2013-Science
TL;DR: The isolation of two giant viruses, one off the coast of central Chile, the other from a freshwater pond near Melbourne, without morphological or genomic resemblance to any previously defined virus families are reported.
Abstract: Ten years ago, the discovery of Mimivirus, a virus infecting Acanthamoeba, initiated a reappraisal of the upper limits of the viral world, both in terms of particle size (>0.7 micrometers) and genome complexity (>1000 genes), dimensions typical of parasitic bacteria. The diversity of these giant viruses (the Megaviridae) was assessed by sampling a variety of aquatic environments and their associated sediments worldwide. We report the isolation of two giant viruses, one off the coast of central Chile, the other from a freshwater pond near Melbourne (Australia), without morphological or genomic resemblance to any previously defined virus families. Their micrometer-sized ovoid particles contain DNA genomes of at least 2.5 and 1.9 megabases, respectively. These viruses are the first members of the proposed "Pandoravirus" genus, a term reflecting their lack of similarity with previously described microorganisms and the surprises expected from their future study

498 citations

Journal ArticleDOI
TL;DR: A third type of giant virus combining the Pandoravirus morphology with a gene content more similar to that of icosahedral DNA viruses is isolated from a >30,000-y-old radiocarbon-dated sample of Siberian permafrost, suggesting that pandorav virus-like particles may correspond to an unexplored diversity of unconventional DNA virus families.
Abstract: The largest known DNA viruses infect Acanthamoeba and belong to two markedly different families. The Megaviridae exhibit pseudo-icosahedral virions up to 0.7 μm in diameter and adenine–thymine (AT)-rich genomes of up to 1.25 Mb encoding a thousand proteins. Like their Mimivirus prototype discovered 10 y ago, they entirely replicate within cytoplasmic virion factories. In contrast, the recently discovered Pandoraviruses exhibit larger amphora-shaped virions 1 μm in length and guanine–cytosine-rich genomes up to 2.8 Mb long encoding up to 2,500 proteins. Their replication involves the host nucleus. Whereas the Megaviridae share some general features with the previously described icosahedral large DNA viruses, the Pandoraviruses appear unrelated to them. Here we report the discovery of a third type of giant virus combining an even larger pandoravirus-like particle 1.5 μm in length with a surprisingly smaller 600 kb AT-rich genome, a gene content more similar to Iridoviruses and Marseillevirus, and a fully cytoplasmic replication reminiscent of the Megaviridae. This suggests that pandoravirus-like particles may be associated with a variety of virus families more diverse than previously envisioned. This giant virus, named Pithovirus sibericum, was isolated from a >30,000-y-old radiocarbon-dated sample when we initiated a survey of the virome of Siberian permafrost. The revival of such an ancestral amoeba-infecting virus used as a safe indicator of the possible presence of pathogenic DNA viruses, suggests that the thawing of permafrost either from global warming or industrial exploitation of circumpolar regions might not be exempt from future threats to human or animal health.

401 citations


Cited by
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Journal ArticleDOI
TL;DR: This version of MAFFT has several new features, including options for adding unaligned sequences into an existing alignment, adjustment of direction in nucleotide alignment, constrained alignment and parallel processing, which were implemented after the previous major update.
Abstract: We report a major update of the MAFFT multiple sequence alignment program. This version has several new features, including options for adding unaligned sequences into an existing alignment, adjustment of direction in nucleotide alignment, constrained alignment and parallel processing, which were implemented after the previous major update. This report shows actual examples to explain how these features work, alone and in combination. Some examples incorrectly aligned by MAFFT are also shown to clarify its limitations. We discuss how to avoid misalignments, and our ongoing efforts to overcome such limitations.

27,771 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

01 Jun 2012
TL;DR: SPAdes as mentioned in this paper is a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler and on popular assemblers Velvet and SoapDeNovo (for multicell data).
Abstract: The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.

10,124 citations

Journal ArticleDOI
10 Mar 1970

8,159 citations

01 Aug 2000
TL;DR: Assessment of medical technology in the context of commercialization with Bioentrepreneur course, which addresses many issues unique to biomedical products.
Abstract: BIOE 402. Medical Technology Assessment. 2 or 3 hours. Bioentrepreneur course. Assessment of medical technology in the context of commercialization. Objectives, competition, market share, funding, pricing, manufacturing, growth, and intellectual property; many issues unique to biomedical products. Course Information: 2 undergraduate hours. 3 graduate hours. Prerequisite(s): Junior standing or above and consent of the instructor.

4,833 citations