Orient & Méditerranée

Agonist-activated Ca2+ entry plays a critical role in Ca2+ signalling in non-excitable cells. One mode of such entry is activated as a consequence of the depletion of intracellular Ca2+ stores. This depletion is sensed by the protein STIM1 in the endoplasmic reticulum, which then translocates to regions close to the plasma membrane where it induces the activation of store-operated conductances. The most thoroughly studied of these conductances are the Ca2+ release-activated Ca2+ (CRAC) channels, and recent studies have identified the protein Orai1 as comprising the essential pore-forming subunit of these channels. Although evidence suggests that Orai1 can assemble as homomultimers, whether this assembly is necessary for the formation of functional CRAC channels and, if so, their relevant stoichiometry is unknown. To examine this, we have used an approach involving the expression of preassembled tandem Orai1 multimers comprising different numbers of subunits into cells stably overexpressing STIM1, followed by the recording of maximally activated CRAC channel currents. In each case, any necessity for recruitment of additional Orai1 units to these preassembled multimers in order to form functional channels was evaluated by coexpression with a dominant-negative Orai1 mutant. In this way we were able to demonstrate, for the first time, that the functional CRAC channel pore is formed by a tetrameric assembly of Orai1 subunits.

Recent studies have indicated a critical role for STIM (stromal interacting molecule) proteins in the regulation of the store-operated mode of receptor-activated Ca2+ entry. Current models emphasize the role of STIM located in the endoplasmic reticulum membrane, where a Ca2+-binding EF-hand domain within the N-terminal of the protein lies within the lumen and is thought to represent the sensor for the depletion of intracellular Ca2+ stores. Dissociation of Ca2+ from this domain induces the aggregation of STIM to regions of the ER immediately adjacent to the plasma membrane where it acts to regulate the activity of store-operated Ca2+ channels. However, the possible effects of STIM on other modes of receptor-activated Ca2+ entry have not been examined. Here we show that STIM1 also regulates the arachidonic-acid-regulated Ca2+-selective (ARC) channels - receptor-activated Ca2+ entry channels whose activation is entirely independent of store depletion. Regulation of the ARC channels by STIM1 does not involve dissociation of Ca2+ from the EF-hand, or any translocation of STIM1. Instead, a critical role of STIM1 resident in the plasma membrane is indicated. Thus, exposure of intact cells to an antibody targeting the extracellular N-terminal domain of STIM1 inhibits ARC channel activity without significantly affecting the store-operated channels. A similar specific inhibition of the ARC channels is seen in cells expressing a STIM1 construct in which the N-linked glycosylation sites essential for the constitutive cell surface expression of STIM1, were mutated. We conclude that, in contrast to store-operated channels, regulation of ARC channels by STIM1 depends exclusively on the pool of STIM1 constitutively residing in the plasma membrane. These data demonstrate that STIM1 is a more universal regulator of Ca2+ entry pathways than previously thought, and appears to have multiple modes of action.

The Arabian Peninsula is a key region for understanding climate change and human occupation history in a marginal environment. The Mundafan palaeolake is situated in southern Saudi Arabia, in the Rub' al-Khali (the 'Empty Quarter'), the world's largest sand desert. Here we report the first discoveries of Middle Palaeolithic and Neolithic archaeological sites in association with the palaeolake. We associate the human occupations with new geochronological data, and suggest the archaeological sites date to the wet periods of Marine Isotope Stage 5 and the Early Holocene. The archaeological sites indicate that humans repeatedly penetrated the ameliorated environments of the Rub' al-Khali. The sites probably represent short-term occupations, with the Neolithic sites focused on hunting, as indicated by points and weaponry. Middle Palaeolithic assemblages at Mundafan support a lacustrine adaptive focus in Arabia. Provenancing of obsidian artifacts indicates that Neolithic groups at Mundafan had a wide wandering range, with transport of artifacts from distant sources.

Following the discovery of items that look like resins at the medieval site of Sharma (Hadramawt coast, Yemen, c. 11th century ad ), chemical investigations were carried out in order to determine their nature and geographic origin. By combining visual observation, infrared spectroscopy, direct inlet electron ionization – mass spectrometry (DI EI–MS) and pyrolysis gas chromatography – mass spectrometry (Py GC–MS) or gas chromatography – mass spectrometry (GC–MS) analyses, it was demonstrated that 84% of the samples were harvested from Hymenaea trees growing in Madagascar and East Africa. Contrary to what was thought previously, frankincense, identified with certainty in only two samples, was thus not the main resin exploited at Sharma. These results are of prime importance for reconsidering the trading routes of resins passing through Sharma, a site that was obviously strongly connected with Africa during the Middle Ages.

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Michel Balard est l'un des historiens qui, loin des évocations nostalgiques, des exclusions communautaires, des oppositions irréductibles, travaille à une histoire totale de l'espace méditerranéen. Dans ses cours, ses conférences, ses travaux personnels comme dans les recherches collectives qu'il a animées, il a placé les croisades, les conflits et les échanges de toute nature, les phénomènes de colonisation et de migration au coeur d'un vaste mouvement d'expansion occidentale qui se déploie à l'époque médiévale sous des formes complexes, et dont l'héritage se fait sentir encore aujourd'hui. À l'issue d'une longue et fructueuse carrière universitaire, ses élèves, ses collègues, ses amis ont à coeur d'emprunter les Chemins d'outre-mer qu'il leur avait ouverts, chemins multiples reliant les civilisations byzantine, musulmane et occidentale qui se sont partagé, à la fois rivales et unies, l'espace méditerranéen au Moyen Age. Ce double volume, qui rassemble plus d'une soixantaine de contributions, invite le lecteur à suivre sur ces chemins pèlerins et croisés, marchands et voyageurs, et ainsi à mieux comprendre les formes et les enjeux des relations qui se sont développées d'une rive à l'autre de la Méditerranée.

Abstract This article demonstrates that among violent Islamists engineers with a degree, individuals with an engineering education are three to four times more frequent than we would expect given the share of engineers among university students in Islamic countries. We then test a number of hypotheses to account for this phenomenon. We argue that a combination of two factors – engineers’ relative deprivation in the Islamic world and mindset – is the most plausible explanation.

The attempts at reunion of the Roman and Orthodox Churches, from the antecedents of the Council of Lyons (1274) to the Council of Florence (1439), have brought forth an abundant historical literature characterised for a long time by the confessional commitment of its authors in Western as well as Eastern Europe. Historical interpretations of the Union have been heavily influenced by the various politico-religious contexts in which they were produced, following closely the evolution of the relations between Rome and Orthodoxy down to the Ecumenism of the second half of the twentieth century. Recent studies aim at a more global consideration of the question, beyond its strictly religious significance: focus is more and more placed on the nature of the reception of the Union in Byzantium and on the conflicts that it has provoked within Greek society.

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Although the ancient site of Utica has been studied since the 19th century, the location of its harbors remains unresolved as they were buried under sediments as the Mejerda delta prograded and left Utica 10 km inland. Using relief data and a coring survey with sedimentological analysis, we identify the dynamics of the delta's progradation, which produced a double system of alluvial fans. These show that the ancient bay of Utica silted up faster and earlier than was thought, probably before the end of the Punic period. Combined with the radiocarbon dates from coring, this suggests that the harbor lay on the north‐western side of the Utica promontory, communicating with the sea by a marine corridor west of the northern compartment of the delta. As the infilling of the ancient bay progressed, this corridor narrowed until it disappeared completely in the early 5th/mid‐6th century A.D., when a peat bog developed on the northern side of the promontory, sealing the fate of Utica as a port. This relative environmental stability ended in the 9th–10th century A.D. when about 4 m of sediment, probably of fluvial origin, covered the peat bog, leaving the site more than 4.5 m above the local sea level.

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This volume presents the inscriptions recorded in 2004 along the so-called Darb al-Bakrah, an ancient north–south caravan track connecting Hegra with Petra. The inscriptions were found at a number of sites along the track. They are carved in a variety of scripts and languages, among which are Imperial Aramaic, Nabataean, Nabataeo-Arabic, Palmyrene, Ancient South Arabian, Ancient North Arabian (Taymanitic, Dadanitic, Hismaic, Safaitic, Thamudic B, C, and D, etc.), and Greek. The Arabic inscriptions and the rock drawings will be published in separate volumes. The inscriptions are edited by six scholars specialised in the history and epigraphy of ancient Arabia.

édition et trad. en collaboration avec G. Troupeau

Abstract This article explores how knowledge was created, acquired, organized, and transmitted in writing by scholars and intellectuals in the kingdom of Ugarit on the Mediterranean coast of Syria, best documented for the thirteenth century BC, with special attention to the social, cultural and political backgrounds against which such literary activities were pursued.

REB 45 1987 France p. 165-174 Marie-Hélène Congourdeau, Frère Simon le Constantinopolitain, O.P. (1235?-1325?). — L'article, présenté comme communication au 15e Congrès International d'Études Byzantines, brosse un portrait de fr. Simon de Constantinople, dominicain du couvent de Péra au début du 14e siècle. L'analyse des lettres (conservées dans le Vatic, gr. 1104 et le Sinait. gr. 1706) qu'il envoya à diverses personnalités byzantines de son époque, à propos de la procession du Saint Esprit, révèle un homme de culture essentiellement grecque, fait rare chez les frères prêcheurs de son époque. Cette correspondance donne également des renseignements précieux sur des documents concernant la controverse latino-grecque : mention d'un concile romain en 380 sur le Filioque et d'un manuscrit (perdu) donnant une version unique du texte grec des Dialogues de Grégoire le Grand.

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REB 45 1987 France p. 175-181 Marie-Hélène Congourdeau, Note sur les Dominicains de Constantinople au début du 14e siècle. — L'analyse de deux traités latins émanant de la communauté de Péra permet de mieux cerner la montée de l'hostilité grecque contre les frères prêcheurs de Constantinople, qui aboutit à leur départ pour Péra en 1307. Leur confrontation avec la correspondance de fr. Simon de Constantinople apporte des éléments nouveaux à propos de deux personnages byzantins : le nomophylax Iôannès et le moine Sophonias, ambassadeur d'Andronic II auprès de Charles II d'Anjou en 1294.

Pdf : http://www.jstor.org/stable/41223754