105 research outputs found
Couleurs et dorures du portail roman de Cluny III. Restitution en 3D d’une œuvre disparue
National audienceLa construction de l’ancienne abbaye Saint-Pierre-et-Saint-Paul de Cluny s’est échelonnée dans le temps, avec une première consécration du chevet en 1095, et une autre dédicace en 1130, correspondant vraisemblablement à une nouvelle étape d’avancement de la basilique romane.Le portail, qui s’ouvrait sur la nef centrale, daté entre 1100 et 1120, figure parmi les créations romanes de grande envergure qui nécessita des techniques exceptionnelles. Il mesurait 5,60 m de large et 3,25 m de hauteur, pour une épaisseur de 40 cm. Selon la description de Benoît Dumolin au xviiie siècle, le tympan aurait été sculpté dans un bloc monolithe, tout comme le linteau, ce qui constitue une véritable prouesse technique, d’autant plus qu’il n’y avait pas de trumeau.La poudre explosive, utilisée pour accélérer la destruction de l’abbaye au début du xixe siècle, a fortement dégradé le portail roman; les morceaux de la façade ont été retrouvés dans les remblais de la rue qui traversait l’avant-nef; seuls 5 à 10 % du portail nous sont parvenus. Certains fragments ont été mis au jour par K. J. Conant dans les années 1930, et plus de 6 000 fragments provenant de toutes les parties de l’avant-nef ont été sauvés de l’oubli en 1989 lors du déblaiement de ce secteur
Couleurs et dorures du portail roman de Cluny III. Restitution en 3D d’une œuvre disparue
La construction de l’ancienne abbaye Saint-Pierre-et-Saint-Paul de Cluny s’est échelonnée dans le temps, avec une première consécration du chevet en 1095, et une autre dédicace en 1130, correspondant vraisemblablement à une nouvelle étape d’avancement de la basilique romane. Le portail, qui s’ouvrait sur la nef centrale, daté entre 1100 et 1120, figure parmi les créations romanes de grande envergure qui nécessita des techniques exceptionnelles. Il mesurait 5,60 m de large et 3,25 m de hauteur, pour une épaisseur de 40 cm. Selon la description de Benoît Dumolin au xviiie siècle, le tympan aurait été sculpté dans un bloc monolithe, tout comme le linteau, ce qui constitue une véritable prouesse technique, d’autant plus qu’il n’y avait pas de trumeau. La poudre explosive, utilisée pour accélérer la destruction de l’abbaye au début du xixe siècle, a fortement dégradé le portail roman; les morceaux de la façade ont été retrouvés dans les remblais de la rue qui traversait l’avant-nef; seuls 5 à 10 % du portail nous sont parvenus. Certains fragments ont été mis au jour par K. J. Conant dans les années 1930, et plus de 6 000 fragments provenant de toutes les parties de l’avant-nef ont été sauvés de l’oubli en 1989 lors du déblaiement de ce secteur
Arabidopsis chloroplast quantitative editotype
AbstractChloroplast C-to-U RNA editing is an essential post-transcriptional process. Here we analyzed RNA editing in Arabidopsis thaliana using strand-specific deep sequencing datasets from the wild-type and a mutant defective in RNA 3′ end maturation. We demonstrate that editing at all sites is partial, with an average of 5–6% of RNAs remaining unedited. Furthermore, we identified nine novel sites with a low extent of editing. Of these, three sites are absent from the WT transcriptome because they are removed by 3′ end RNA processing, but these regions accumulate, and are edited, in a mutant lacking polynucleotide phosphorylase
Digital rebirth of the greatest church of Cluny Maior Ecclesia: From optronic surveys to real time use of the digital Model
Our multidisciplinary team has virtually reconstructed the greatest church of the Romanesque period in Europe. The third church of the Abbey of Cluny (12th c.) has been destroyed after the French Revolution, leaving only 8% of the building standing. Many documents have been studied, to include the latest archaeological knowledge in the virtual model. Most remains have been scanned for CAD restitution. The mock-up of the church needed 1600 different numerical files, including the scanned pieces and the anastylosis of a Romanesque portal, a Gothic façade and a mosaic pavement. We faced various difficulties to assemble the different elements of the huge building, and to include the digitized parts. Our workflow consisted in generating geometrical shapes of the church, enriched with metadata such as texture, material... The whole mock up was finally exported to dedicated software to run the rendering step. Our work consisted in creating a whole database of 3D models as well as 2D sources (plans, engravings, pictures...) accessible by the scientific community. The scientific perspectives focus on a representation in virtual immersion of the grand church at scale 1 and an access to the digital mock-up through Augmented Reality.Gunzo projec
Intron RNA editing is essential for splicing in plant mitochondria
Most plant mitochondria messenger RNAs (mRNAs) undergo editing through C-to-U conversions located mainly in exon sequences. However, some RNA editing events are found in non-coding regions at critical positions in the predicted secondary and tertiary structures of introns, suggesting that RNA editing could be important for splicing. Here, we studied the relationships between editing and splicing of the mRNA encoding the ribosomal protein S10 (rps10), which has a group II intron and five editing sites. Two of them, C2 and C3, predicted to stabilize the folded structure of the intron necessary for splicing, were studied by using rps10 mutants introduced into isolated potato mitochondria by electroporation. While mutations of C2 involved in EBS2/IBS2 interactions did not affect splicing, probably by the presence of an alternative EBS2 0 region in domain I of the intron, the edition of site C3 turned out to be critical for rps10 mRNA splicing; only the edited (U) form of the transcript was processed. Interestingly, RNA editing was strongly reduced in transcripts from two different intronless genes, rps10 from potato and cox2 from wheat, suggesting that efficient RNA processing may require a close interaction of factors engaged in different maturation processes. This is the first report linking editing and splicing in conditions close to the in vivo situation
An mTRAN-mRNA interaction mediates mitochondrial translation initiation in plants
Plant mitochondria represent the largest group of respiring organelles on the planet. Plant mitochondrial messenger RNAs (mRNAs) lack Shine-Dalgarno-like ribosome-binding sites, so it is unknown how plant mitoribosomes recognize mRNA. We show that “mitochondrial translation factors” mTRAN1 and mTRAN2 are land plant–specific proteins, required for normal mitochondrial respiration chain biogenesis. Our studies suggest that mTRANs are noncanonical pentatricopeptide repeat (PPR)–like RNA binding proteins of the mitoribosomal “small” subunit. We identified conserved Adenosine (A)/Uridine (U)-rich motifs in the 5′ regions of plant mitochondrial mRNAs. mTRAN1 binds this motif, suggesting that it is a mitoribosome homing factor to identify mRNAs. We demonstrate that mTRANs are likely required for translation of all plant mitochondrial mRNAs. Plant mitochondrial translation initiation thus appears to use a protein-mRNA interaction that is divergent from bacteria or mammalian mitochondria
Chemical Optimization of Selective Pseudomonas aeruginosa LasB Elastase Inhibitors and Their Impact on LasB-Mediated Activation of IL-1β in Cellular and Animal Infection Models
LasB elastase is a broad-spectrum exoprotease and a key virulence factor of Pseudomonas aeruginosa, a major pathogen causing lung damage and inflammation in acute and chronic respiratory infections. Here, we describe the chemical optimization of specific LasB inhibitors with druglike properties and investigate their impact in cellular and animal models of P. aeruginosa infection. Competitive inhibition of LasB was demonstrated through structural and kinetic studies. In vitro LasB inhibition was confirmed with respect to several host target proteins, namely, elastin, IgG, and pro-IL-1 beta. Furthermore, inhibition of LasBmediated IL-1 beta activation was demonstrated in macrophage and mouse lung infection models. In mice, intravenous administration of inhibitors also resulted in reduced bacterial numbers at 24 h. These highly potent, selective, and soluble LasB inhibitors constitute valuable tools to study the proinflammatory impact of LasB in P. aeruginosa infections and, most importantly, show clear potential for the clinical development of a novel therapy for life-threatening respiratory infections caused by this opportunistic pathogen
The RNA Editing Pattern of cox2 mRNA Is Affected by Point Mutations in Plant Mitochondria
The mitochondrial transcriptome from land plants undergoes hundreds of specific C-to-U changes by RNA editing. These events are important since most of them occur in the coding region of mRNAs. One challenging question is to understand the mechanism of recognition of a selected C residue (editing sites) on the transcript. It has been reported that a short region surrounding the target C forms the cis-recognition elements, but individual residues on it do not play similar roles for the different editing sites. Here, we studied the role of the −1 and +1 nucleotide in wheat cox2 editing site recognition using an in organello approach. We found that four different recognition patterns can be distinguished: (a) +1 dependency, (b) −1 dependency, (c) +1/−1 dependency, and (d) no dependency on nearest neighbor residues. A striking observation was that whereas a 23 nt cis region is necessary for editing, some mutants affect the editing efficiency of unmodified distant sites. As a rule, mutations or pre-edited variants of the transcript have an impact on the complete set of editing targets. When some Cs were changed into Us, the remaining editing sites presented a higher efficiency of C-to-U conversion than in wild type mRNA. Our data suggest that the complex response observed for cox2 mRNA may be a consequence of the fate of the transcript during mitochondrial gene expression
Intron RNA editing is essential for splicing in plant mitochondria
Most plant mitochondria messenger RNAs (mRNAs) undergo editing through C-to-U conversions located mainly in exon sequences. However, some RNA editing events are found in non-coding regions at critical positions in the predicted secondary and tertiary structures of introns, suggesting that RNA editing could be important for splicing. Here, we studied the relationships between editing and splicing of the mRNA encoding the ribosomal protein S10 (rps10), which has a group II intron and five editing sites. Two of them, C2 and C3, predicted to stabilize the folded structure of the intron necessary for splicing, were studied by using rps10 mutants introduced into isolated potato mitochondria by electroporation. While mutations of C2 involved in EBS2/IBS2 interactions did not affect splicing, probably by the presence of an alternative EBS2′ region in domain I of the intron, the edition of site C3 turned out to be critical for rps10 mRNA splicing; only the edited (U) form of the transcript was processed. Interestingly, RNA editing was strongly reduced in transcripts from two different intronless genes, rps10 from potato and cox2 from wheat, suggesting that efficient RNA processing may require a close interaction of factors engaged in different maturation processes. This is the first report linking editing and splicing in conditions close to the in vivo situation
SAR Studies Leading to the Identification of a Novel Series of Metallo-β-lactamase Inhibitors for the Treatment of Carbapenem-Resistant Enterobacteriaceae Infections That Display Efficacy in an Animal Infection Model
The clinical effectiveness of carbapenem antibiotics such as meropenem is becoming increasingly compromised by the spread of both metallo-β-lactamase (MBL) and serine-β-lactamase (SBL) enzymes on mobile genetic elements, stimulating research to find new β-lactamase inhibitors to be used in conjunction with carbapenems and other β-lactam antibiotics. Herein, we describe our initial exploration of a novel chemical series of metallo-β-lactamase inhibitors, from concept to efficacy, in a survival model using an advanced tool compound (ANT431) in conjunction with meropenem
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