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Journeys into the invisible: Shamanic Technologies of the Imagination
No full textInternational audienceJourneys into the Invisible is a lively exploration of the traditions of shamanism in the Far North of Eurasia and North America. Charles Stépanoff draws on ethnographic literature and his fieldwork in Siberia to reveal the immense contribution to the scope of human imagination made by shamans and the cognitive techniques they developed over the centuries.Northern Shamans travel in mind in ways that appear mysterious to Westerners, but which rely on the human capacity of imagination. They perceive themselves simultaneously in two types of space—one visible, the other invisible—putting them in contact and establishing links with non-human beings in their surroundings. Shamans share their experience of mind travel with their patients, families, or the wider community, allowing them to participate in their odyssey through the invisible. Stépanoff offers an anthropological reflection on the relationships between our uses of the imagination, our relationships with the environment, and the emergence of social hierarchies.This work will appeal to anthropologists as well as to anyone interested in learning about the power of imagination from the masters of the invisible, the shamans of the Far North
The thiolation of U34 at carbon 2 in tRNA by Escherichia coli MnmA precedes modification at carbon 5 and is dependent on a [4Fe-4S] cluster
No full textInternational audienceChemical modifications of transfer RNAs (tRNAs) fine-tune the recognition of messenger RNA codons on the ribosome for accurate protein translation. Uridine 34 (U34) of the anticodon of three tRNAs is modified in all domains of life. In bacteria, U34 is modified at C5 by aminomethyl derivatives by MnmE/MnmG enzymes and at C2 by a sulfur atom by MnmA enzymes from two distinct classes. Ctype MnmAs possess a CXXC+ C catalytic motif, in which cysteines bind a [4Fe-4S] cluster essential for catalysis. D-type MnmAs possess a DXXC+ C catalytic motif, which can also bind a [4Fe-4S] cluster, but the function of the cluster is controversial. To shed light on the role of the [4Fe-4S] cluster in the thiolation reaction, we report here new in vitro catalytic assays of the D-type Escherichia coli MnmA enzyme (EcMnmA) before, and after cluster reconstitution under anaerobic conditions. We confirm that that only holo-EcMnmA can thiolate U34 in a tRNA transcript using sulfide as a sulfur source and show that 1) a bulk E. coli mnmA tRNA, containing the C5 modification, is not a substrate, indicating that thiolation at C2 precedes modification at C5, 2) cysteine with IscS cannot provide the sulfur atom for tRNA thiolation without a reductant and 3) the variant, in which the aspartate of the DXXC + C motif is replaced by cysteine, is efficient in U34-tRNA thiolation in vitro but not in vivo, raising questions about the in vivo function of soft cluster coordination
Dissecting the Mechanism of Biosynthesis of Sulfurated Biomolecules: The Case of tRNA Sulfuration
No full textInternational audienceSulfuration of biomolecules is a crucial biochemical process responsible for producing essential organic cofactors, coenzymes, vitamins, and other sulfurated biomolecules. In particular, thio-modified nucleosides in transfer RNA (tRNA) play a key role in ensuring the accuracy and efficiency of genetic translation. Although sulfurating enzymes have been studied structurally and biochemically since the early 2000s, detailed mechanistic analyses remain limited. In particular, the importance of reductants used in catalytic assays is often underappreciated.In recent years, the use of anaerobic conditions has led to the discovery, in many of these enzymes, of an air-sensitive iron-sulfur cluster that is essential for catalysis. This led to the proposal of a catalytic mechanism involving a [4Fe-5S] intermediate, distinct from the previously accepted persulfide-based pathway. As this remains a debated topic, the current understanding of both mechanisms and the role of reductants warrants critical evaluation.</p
Friedman-Ramanujan functions in random hyperbolic geometry and application to spectral gaps II
No full textThe core focus of this series of two articles is the study of the distribution of the length spectrum of closed hyperbolic surfaces of genus , sampled randomly with respect to the Weil-Petersson probability measure. In the first article, we introduced a notion of local topological type , and established the existence of a density function describing the distribution of the lengths of all closed geodesics of type in a genus hyperbolic surface. We proved that admits an asymptotic expansion in powers of . We introduced a new class of functions, called Friedman-Ramanujan functions, and related it to the study of the spectral gap of the Laplacian. In this second part, we provide a variety of new tools allowing to compute and estimate the volume functions . Notably, we construct new sets of coordinates on Teichmüller spaces, distinct from Fenchel-Nielsen coordinates, in which the Weil-Petersson volume has a simple form. These coordinates are tailored to the geodesics we study, and we can therefore prove nice formulae for their lengths. We use these new ideas, together with a notion of pseudo-convolutions, to prove that the coefficients of the expansion of in powers of are Friedman-Ramanujan functions, for any local topological type . We then exploit this result to prove that, for any ε>0, with probability going to one as , or, in other words, typical hyperbolic surfaces have an asymptotically optimal spectral gap
Altered DNA methylation of the ABO gene is associated with differential plasma levels of von willebrand factor and E‐selectin
No full textInternational audienceBackground The ABO blood group system is associated with differential susceptibility to thrombotic vascular diseases. ABO is also known to be a strong trans ‐protein quantitative trait locus for plasma proteins involved in cell adhesion and hemostasis. Study Design and Method To further investigate these associations, we integrated epigenomic, genomic, and proteomic data from the Milieu Intérieur cohort. We used the rs8176719 SNP to classify donors as either type O or non‐O, and used linear models to compare levels of 229 plasma proteins in 400 donors, including age, sex, cytomegalovirus serostatus, and secretor status as covariates. ResultsWe observed increased levels of soluble E‐selectin and decreased levels of von Willebrand Factor (vWF) in O donors compared with non‐O donors. By performing an epigenome‐wide association study, we identified 23 differentially methylated CpG sites between blood types, which were all located in the ABO gene. Notably, CpG sites in the ABO promoter region of type O donors were less methylated than those of the non‐O donors. Using mediation analysis, we found that these differences in DNA methylation partially explained the effects of blood group on differential E‐selectin and vWF plasma levels. Discussion We find differentially methylated CpG sites between blood types and provide new evidence that ABO blood group status affects circulating levels of specific proteins
Investigation of the sero-epidemiology of vaccine preventable diseases and common viral infections in French populations
No full textInternational audienceBackgroundVaccine-preventable diseases and common viral infections pose substantial public health challenges worldwide. Applying multiplex serological assays to samples collected from cross-sectional studies allows assessment of population-level immunity to a broad range of pathogens.MethodsWe develop a high-throughput multiplex serological assay using bead-based Luminex technology to measure IgG antibody responses to a broad panel of pathogens. Vaccine preventable diseases include pertussis, diphtheria, tetanus, measles, mumps, and rubella. Common viral infections include adenovirus, cytomegalovirus, Epstein-Barr virus, chickenpox, respiratory syncytial virus, echovirus, Coxsackie B virus, rhinovirus, norovirus, rotavirus, influenza A, hepatitis A, hepatitis E, and the seasonal coronaviruses 229E, OC43, NL63, and HKU1. Measured antibody responses are analysed with statistical models to assess seroprevalence within the French population.ResultsThe analysis of 2132 serum samples from French children and adults reveals notable variation in seroprevalence among different age groups. Consistently high seroprevalence for endemic viruses is observed across all age groups, suggesting widespread exposure from a young age and continuous exposure throughout life. Similarly, mandatory vaccine seroprevalence remains consistently high, reflecting a strong vaccination coverage in France.ConclusionsThese findings highlight the potential of high-throughput multiplex serology assays for routine surveillance of common viral infections and assessment of vaccine coverage
Experts et expertise des thérapeutes en Mésopotamie : une étude à travers les textes du XVIIIe siècle av. J.-C.
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Quand écrire, c’est faire lien. Rédiger un statut associatif en Croatie (post-)habsbourgeoise
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La Syrie, le Levant et la question égyptienne selon les sources textuelles de l'époque paléo-babylonienne
No full textInternational audienceUn grand nombre de documents cunéiformes de l’époque paléo-babylonienne (environ 1900–1600 av. J.-C.) fournit des informations sur la Syrie et le Levant, depuis Hazor au sud jusqu’à Alalah au nord, et de Byblos sur la Méditerranée jusqu’à Palmyre, oasis et carrefour routier dans la steppe syrienne. Cette communication propose une introduction dans l’organisation politique du Levant. Les différentes populations mentionnées dans les textes, sédentaires comme nomades, seront présentées. Enfin, les données textuelles relatives à l’ancienne Tukriš est résumé. L'identification de Tukriš avec le toponyme Dugurasu des archives d’Ebla (probablement le nom du delta du Nil), ne peut pas être affirmée avec la documentation actuellement disponible
Altbabylonische Codices und die Rechtspraxis im Spiegel der Alltagstexte – Witwen, „Strohwitwen“ und ihre Kinder
No full textInternational audienceDas Gesetzeswerk Hammurabis enthält Satzungen, dank derer die Rechte und Pflichten zweier Gruppen von verheirateten Frauen geregelt wurden, deren Mann abwesend war – Witwen und „Strohwitwen“. Dem Gesetzgeber ging es vorrangig um die Sicherung des Erbes der Kinder bzw. um die Wiederherstellung der Rechte des kriegsgefangenen Vaters. Dieser Beitrag zeigt anhand von zwei außergewöhnlichen Fällen, wie das soziale Umfeld und die Autoritäten reagierten, wenn von Frauen öffentlich eingefordert wurde, den zivilen Status vaterloser Kinder zu sichern, und belegt damit eindrücklich die praktische Anwendung der in Hammurabis Gesetzeswerk niedergelegten Regelungen.Hammurabi's code of laws contains statutes regulating the rights and obligations of two groups of married women whose husbands were absent – widows or wives of war prisoners. The primary concern of the legislator was to secure the inheritance of the children and to restore the rights of the father prisoner of war when he returned home. This article uses two extraordinary cases to show how the social environment and the authorities reacted when women publicly demanded that the civil status of such fatherless children be secured, thus impressively demonstrating the practical application of the regulations laid down in Hammurabi's legal code.Le code de Hammurabi règlait les droits et les devoirs de deux groupes de femmes mariées dont le mari était absent : les veuves et les femmes dont le mari était prisonnier de guerre. Le législateur avait pour priorité de garantir l'héritage des enfants et de rétablir les droits du père prisonnier de guerre lors de son retour. Deux cas exceptionnels présentés dans le chapitre montrent comment l'environnement social et les autorités réagissaient lorsque des femmes exigeaient publiquement que le statut civil des enfants sans père soit garanti. Les exemples choisis prouvent l'application concrète des règles énoncées dans le code de Hammurabi