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The Lutheran (Lu) and Lu(v13) blood group glycoproteins function as receptors for extracellular matrix laminins. Lu and Lu(v13) are linked to the erythrocyte cytoskeleton through a direct interaction with spectrin. However, neither the molecular basis of the interaction nor its functional consequences have previously been delineated. In the present study, we defined the binding motifs of Lu and Lu(v13) on spectrin and identified a functional role for this interaction. We found that the cytoplasmic domains of both Lu and Lu(v13) bound to repeat 4 of the α spectrin chain. The interaction of full-length spectrin dimer to Lu and Lu(v13) was inhibited by repeat 4 of α-spectrin. Further, resealing of this repeat peptide into erythrocytes led to weakened Lu-cytoskeleton interaction as demonstrated by increased detergent extractability of Lu. Importantly, disruption of the Lu-spectrin linkage was accompanied by enhanced cell adhesion to laminin. We conclude that the interaction of the Lu cytoplasmic tail with the cytoskeleton regulates its adhesive receptor function.

International audience; A sediment sequence (SP05, 12.5 m long) was taken from the deep zone of Lake Saint-Point (850 m a.s.l.). Sedimentological analyses highlight two main contrasted periods of sedimentation: the Last Glacial Maximum (LGM)/Late Glacial characterized by high silicates and quartz contents the Holocene dominated by the carbonated fraction. At the beginning of the Holocene (11 400 years cal. BP), silicates fraction flux abruptly decreased. The shift between the Late Glacial and the Holocene periods may be explained by forest development in the catchment. From 10 200 to 6800 years cal. BP, silicates and detrital carbonate fractions remained stable before they progressively increased steady till 5000 years cal. BP. Both increases cannot be totally attributed to an anthropic impact since pollen data indicate continuous anthropic activities only dated back from 3000 years cal. BP. They thus resulted from a dominant climatic control. From 5000 years cal. BP, silicates content still increased while detrital carbonates input became steady due to a change in pedogenetic processes affecting the catchment. During the last millennium, silicates and detrital carbonate decreased, probably due to pastureland development

On the basis of sediment and pollen analyses of a radiocarbon-dated sediment sequence from Lake Joux in the Swiss Jura Mountains (west-central Europe), this paper presents a high-resolution record of lake-level and vegetation changes for the last millennium. The lake-level record makes it possible to determine that low-stands of the water-table dominated at c. AD 1200—1400, and from 1720 onward, with interruptions by short-lived rise events at c. AD 1340 and 1840. Highstands prevailed at c. AD 1100, and around AD 1450, 1550 and 1700. The comparison of the Joux lake-level record with a solar irradiance record based on cosmogenic nucleides supports the hypothesis of a major solar forcing of climate variations in west-central Europe over the last millennium. In agreement with other palaeohydrological records established in Western Europe and in the central North Atlantic Ocean, the Joux lake-level record suggests that, on a multicentennial scale, the period of the `Little Ice Age' coincided in the European mid-latitudes with wetter climatic conditions, and probably with an increase in summer precipitation. Variations in the hydrological cycle appear to have been associated with changes in the general atmospheric circulation pattern, probably coupled with variations in oceanic circulation and solar activity. The Joux record also points to changes in water resources expected to result from ongoing global warming. Finally, despite the severe climatic conditions which prevail in the Joux Valley, the human impact history at Lake Joux over the last millennium seems to reflect political choices and economic context more than climatic changes.

Lutheran (Lu) blood group and Basal Cell Adhesion Molecule (BCAM) antigens are both carried by two glycoprotein (gp) isoforms of the immunoglobulin superfamily representing receptors for laminin alpha5 chain. They are expressed in red blood cells, in endothelial cells of vascular capillaries and in epithelial cells of several tissues. Lu/BCAM gps are overexpressed in sickle red blood cells (SS RBCs). Stimulation of SS RBCs by epinephrine activates the PKA depending signaling pathway and induces reinforced Lu/BCAM-mediated adhesion to laminin10/11. We have analyzed the phosphorylation state of Lu/BCAM long isoform cytoplasmic tail and showed that it is phosphorylated by CKII, GSK3b and PKA. Phosphorylation of this isoform in transfected K562 cells is stimulated by effectors of the PKA pathway and induces cell adhesion to laminin10/11. Lu/BCAM gps are highly expressed in endothelial cells and exhibit potential integrin binding motifs. We showed that they interact with integrin alpha4beta1, the unique integrin expressed on the surface of young reticulocytes. Adhesion assays under flow conditions showed that SS RBCs adhere to primary human endothelial cells (HUVEC) after selective activation of intergin alpha4beta1 and that this adhesion is mediated by endothelial Lu/BCAM gps. Our studies show that Lu/BCAM gps expressed either on erythroid or on endothelial cells are involved in SS RBC-endothelium interactions and could play a role in the abnormal adhesion of SS RBCs to vascular endothelium contributing to the vaso-occlusive crises reported for sickle cell disease patients.

A sediment sequence (SP05, 12.5 m long) was taken from the deep zone of the Lake Saint-Point (850 m a.s.l.). Sedimentological analyses highlight two main contrasted periods of sedimentation : the LGM/Late Glacial characterized by high silicates and quartz contain in sediment and the Holocene dominated by the carbonated fraction. At the beginning of the Holocene (11 400 cal. BP), sili¬ cate fraction flux abruptly decreased. The shift between the Late Glacial and the Holocene may be explained by forest development in the catchment area. From 10200 to 6800 cal. BP, silicate and detrital carbonate fractions became steady. They both progressively increased till 5 000 cal. BP. These increases can not be totally attributed to an anthropic impact since pollen data indicate a continuous anthropic activities only from 4000 cal. BP. They resulted from a dominant climatic control. From 5000 cal BP, silicates still increased whereas detrital carbonate input became steady due to a change in vegetation affecting the catchment. During the last millennium, silicate and detrital carbonate decreased probably due to pastureland development to the detriment of cereal cultivation., Une séquence sédimentaire (SP05, 12,5 m de long) a été forée dans la partie profonde du Lac Saint Point (850 m). Les analyses sédimentologiques mettent en évidence deux périodes de sédimentation : le Pléniglaciaire/Tardiglaciaire caractérisé par d'importantes teneurs en silicates (quartz, argiles), et l'Holocène dominé par la sédimentation carbonatée. Au début de l 'Holocène (11 400 cal. BP) les flux de silicates et de carbonates détritiques décroissent brutalement suite au développement de la forêt dans le bassin versant. De 10200 à 6800 cal. BP, les apports silicatés et le détritisme carbonaté sont stables, puis augmentent régulièrement jusqu 'à 5000 cal. BP. Ces augmentations ne peuvent être entièrement assimilées à un impact anthropique puisque les données polliniques indiquent une activité anthropique continue seulement à partir de 4000 cal. BP. Le contrôle climatique apparaît dominant. A partir de 5000 cal. BP, les apports silicatés augmentent alors que le détritisme carbonaté se stabilise. Ce phénomène est la conséquence d'un changement de végétation au sein du bassin versant. Vers 1000 cal. BP, silicates et carbonates détritiques décroissent probablement en raison du développement de pâturages au détriment des cultures céréalières, plus sédimentogènes., Leroux Aurélie, Bichet Vincent, Walter-Simonnet Anne-Véronique, Magny Michel, Adatte Thierry, Gauthier Emilie, Richard Hervé. La séquence Tardiglaciaire-Holocène du Lac de Saint-Point (Jura, France) : dynamique de la végétation et évolution du détritisme. In: Collection EDYTEM. Cahiers de géographie, numéro 6, 2008. Du climat à l’homme, dynamique holocène de l’environnement dans le Jura et les Alpes. pp. 89-98.

Outdoor weathering field trials performed with oxo-degradable polyethylene (PE) thin films were conducted across temperate, grassland, and subtropical sites around Australia. It was found that a site factor, that was apparently independent of total solar dose and temperature, significantly impacted the rate and extent of photo-oxidation. Controlled laboratory-based accelerated aging trials of both PE film with no prodegradant and oxo-degradable PE films (containing iron stearate) revealed that the rate and extent of PE photo-oxidation did not correlate with temperature under the film or UV exposure, but was soil dependent. Under accelerated photo-oxidative conditions, the time to reach embrittlement for a PE film aged over the soil from the temperate site (OM 8.4) was half (24.5 days) the time taken when aged over air (48 days). Further investigation revealed that humic acids and fulvic acids within soil organic matter may contribute to an increased rate of PE photo-oxidation, possibly through the formation of volatile reactive oxygen species that may form under photo-oxidative conditions. The presence of water also had a significant impact on the rate of photo-oxidation. Overall, the impact of soil on PE photo-oxidation was found to be complex and likely dependent at least in part on soil components that varied between different soil types, consequently influencing their photo-chemistry.

The aim of this study is to model atmospheric lead fluxes in two different paleoenvironmental records located in southern Greenland. Fifty five sediment samples collected from the Lake Igaliku sedimentary sequence were analyzed for lead and aluminum concentrations, and lead isotopic compositions. The second archive consists in a previously published dataset, obtained from a minerogenic peat deposit, located at Tasiusaq, 16 km northwest from Lake Igaliku. A flux model fitted to both dataset produces similar results, allowing past anthropogenic atmospheric deposition to be reconstructed. This original method can be easily adapted for other studies where natural inputs dominate over discrete anthropogenic inputs.

International audience; To reconstruct the evolution of livestock in SW Greenland over the last two millennia, we measured the concentration of bile acids in a sedimentary sequence retrieved from Lake Igaliku. Deoxycholic acid (DOC) was the sole bile acid. and was present throughout the sequence.The DOC flux correlated quantitatively with that of coprophilous fungal spores. Maximum DOC and coprophilous fungal spores fluxe was recorded during the two periods of human settlement and grazing activity in the region (i.e. the Norse settlement during the Middle Ages and the recent Danish agricultural phase since 1920). These flux values were consistent with the presence of recent livestock around the lake and are attested to by way of archaeological data relating to the Norse period. In contrast, the DOC and coprophilous fungal spores background during pre-Norse times and the Little Ice Age (LIA), indicated the presence of wild herbivores. Lower DOC and coprophilous fungal spore fluxes values after the Norse abandonment, compared with pre-colonization conditions, could indicate that Norse activity in conjunction with climate pejoration, altered durably the pristine wildlife.Therefore, these quantitative correlations between DOC and coprophilous fungal spores fluxes potentially suggest a quantitative relationship with the livestock grazing in the catchment. The comparison between sedimentary DOC and coprophilous fungal spores provides tremendous highlights on past pastoral dynamics over the last 2000 yr in SW Greenland.

International audience; We present radiometric, palaeoclimatological, palaeoenvironmental and archaeological data for the period 40 000–8000 cal BP in the Jura Mountains (eastern France). These mountains culminate at ∼1700 m a.s.l. and are today characterised by a semi-continental climate. During the Last Glacial Maximum, the range supported a local ice cap. While recent data suggest a possible early ice-cap development during MIS 4, the chronology of the regional LGM and following deglaciation has still to be refined. The complete disappearance of the local ice cap at ca 17 000–16 600 cal BP marked the beginning of accumulation of sediment archives in the Jurassian lakes and mires, which favoured the reconstruction of past changes in climatic and environmental conditions, in addition to faunal remains found in caves and in archaeological sites. Three main successive stages may be distinguished regarding the history of societies. The first stage at ca 40 000–18 700 cal BP was characterized by very few archaeological sites with only discontinuous intermittent occupations, always located outside the Jura range. The second stage, around 18 700–11 700 cal BP, corresponded to an increase in the population density, as suggested by an increasing number of archaeological sites and a progressive colonisation of elevated areas of the Jura Mountains. The third stage at ca 11 700–8000 cal BP coincided with a reinforcement of settlement in the lowland areas as well as a development of long-term occupations in elevated areas. The millennial-scale GS-1 cold event had a more long-lasting and stronger impact on societies than did the 200 year-long 8.2 ka cold event.

International audience; Palaeoenvironmentalists from the Chrono-environment laboratory in Besançon have been working in Greenland since 2006. The Study area is located in southern Greenland, within the Norse Eastern settlement occupied from 986 to 1450 cal. BC. The study aims at characterizing the impact of this first colonization on a pristine environment. The lacustrine sequence was studied with the help of different proxies (palynology, Non Pollen Palynomorph, Diatoms, sedimentology, geochemical and isotope analyses) and, in some site, the Norse settlement was integrated in the Holocene context. About 20 sediment cores were collected during 5 fieldtrips from 2006 to 2013. The Holocene sequence from Igaliku, the medieval Garðar, starts at 8000 cal. AD and the record of pollen rain start at about 6100 cal. AD ; it is one of the best radiocarbon dated sequence of this area. From 6100 to 2500 cal. AD, pollen diagram from Lake Igaliku shows that vegetation is dominated by juniper and willow. Starting in 2500 cal. AD, with the beginning of the neoglacial period, Juniper pollen decreases while dwarf birch and white birch become the dominant tree taxa. Decrease in birch and juniper and the rise in coprophilous fungi are the first evidences of the Norse settlement. The presence of settlers and livestock is clearly recorded: increasing soil erosion frequencies Norse apophytes (sheep sorrel, dandelion, buttercup) and coprophilous fungi. This colonization phase is followed by a period of decreasing human impact at the beginning of the 14th century, with a decrease in coprophilous fungi suggesting a reduced grazing pressure. The regrowth of willow and birch and the disappearance of anthropogenic indicators except sheep sorrel type between the 15th and 18th century demonstrate the abandonment of the settlement, until the development of contemporary agriculture in the 20th century. Impact of modern agriculture on vegetation is comparable to the Norse impact. However, mechanization and fertilization have heavily increased soil erosion and transformed the lake ecosystem.; Depuis 2006, une équipe constituée de paléoenvironnementalistes du laboratoire Chronoenvironnement de Besançon travaille sur les séquences lacustres du sud du Groenland. Le secteur étudié est au cœur de la zone occupée par les viking (l’Eastern settlement) entre 986 et 1450 cal. AD. Le but premier de cette étude était de mettre en évidence l’impact de cette colonisation sur un environnement vierge. L’étude des paramètres biotiques (grains de pollen, microfossiles non polliniques et diatomées) et abiotiques (sédimentologie, géochimie et isotopes) a été étendue à l’ensemble de certaines séquences afin de replacer la partie viking dans son contexte holocène. Cinq missions de terrain ont permis de collecter une vingtaine de séquences lacustres. La séquence sédimentaire prélevée dans le lac d’Igaliku (N61°00’22”, W45°26’28), à côté du site médiéval de Garðar débute aux environs de 8000 cal. BC et l’enregistrement pollinique commence à partir de 6100 cal. AD ; elle fait partie des rares séquences complètes et bien datées (28 dates radiocarbone) de ce secteur subarctique. La première moitié de l’Holocène, jusque vers 2500 cal. BC, est marquée par un couvert végétal dominé par le genévrier et le saule. Ensuite l’apparition des conditions plus humides du Néoglacial favorise l’essor du bouleau glanduleux, puis du bouleau pubescent. Dès la fin du premier millénaire après Jésus-Christ, la colonisation viking est marquée par une pression pastorale qui se traduit par l’augmentation brutale des taux de spores de champignons coprophiles, la diminution des pourcentages de bouleau et l’apparition de plantes importées comme l’oseille, le bouton d’or ou le pissenlit. Le développement de ces activités agropastorales entraine une érosion modérée des sols mais les diatomées montrent que le système lacustre n’est en rien affecté par ces changements. Dès 1300 cal. AD la pression pastorale et l’érosion diminuent, données corroborées par l’archéologie. À l’orée du Petit Âge Glaciaire, les viking se tournent vers une alimentation tirée de la mer aux dépends de l’élevage. Aux environs de 1450 cal. AD, le peuplement disparait mais la résilience est modérée du point de vue de la végétation car les plantes importées se maintiennent. La réintroduction de l’élevage au début du XXe siècle est parfaitement marquée par les différents paramètres d’étude : si l’impact sur la végétation n’est guère différent de ce qui a été observé pendant la période viking, l’érosion est largement supérieure et l’emploi d’engrais bouleverse définitivement l’écosystème lacustre.

Lutheran (Lu) blood group and basal cell adhesion molecule (B-CAM) antigens reside on two glycoprotein (gp) isoforms Lu and Lu(v13) that belong to the Ig superfamily and differ only by the size of their cytoplasmic tail. Lu/B-CAM gps have been recognized as laminin alpha5 receptors on red blood cells and epithelial cells in multiple tissues. It has been shown that sickle red cells exhibit enhanced adhesion to laminin alpha5 when intracellular cAMP is up-regulated by physiological stimuli such as epinephrine and that this signaling pathway is protein kinase A- and Lu/B-CAM-dependent. In this study, we analyzed the relationship between the phosphorylation status of Lu/B-CAM gps and their adhesion function to laminin alpha5. We showed that Lu isoform was phosphorylated in sickle red cells as well as in erythroleukemic K562 and epithelial Madin-Darby canine kidney cells and that this phosphorylation is enhanced by different stimuli of the PKA pathway. Lu gp is phosphorylated by glycogen synthase kinase 3 beta, casein kinase II, and PKA at serines 596, 598, and 621, respectively. Alanine substitutions of serines 596 and 598 abolished phosphorylation by glycogen synthase kinase 3 beta and casein kinase II, respectively, but had no effect on adhesion of K562 cells to laminin under flow conditions. Conversely, mutation of serine 621 prevented phosphorylation by PKA and dramatically reduced cell adhesion. Furthermore, stimulation of K562 cells by epinephrine increased Lu gp phosphorylation by PKA and enhanced adhesion to laminin. It is postulated that modulation of the phosphorylation state of Lu gp might be a critical factor for the sickle red cells adhesiveness to laminin alpha5 in sickle cell disease.

Lutheran (Lu) and Lu(v13), two glycoprotein (gp) isoforms belonging to the immunoglobulin superfamily, represent adhesion molecules that act as erythrocyte receptors for laminin 10/11. These two gps, which differ only by the length of their cytoplasmic tail, carry both Lu blood group and Basal Cell Adhesion Molecule (B-CAM) antigens. Here, analysis of the Triton extractability of recombinant Lu and Lu(v13) gps in K562 transfected cells showed that both gps were mainly associated with the detergent-insoluble material. Patching experiments using Cholera Toxin subunit B indicated that Lu gps were not localized in lipid rafts. Glutathione-S-transferase capture assays showed that the cytoplasmic domain of Lu and Lu(v13) bound to erythroid spectrin, present in a low ionic strength extract from red cell ghosts. Direct interaction with spectrin was confirmed by plasmon resonance assays. Site-directed mutagenesis mapped a major interaction site with spectrin to the RK573-574 motif, located on the cytoplasmic tail of Lu gp, in close vicinity to the inner leaflet of the membrane lipid bilayer. The two Lu adhesion gps represent the first example of a direct link between transmembrane proteins and spectrin in red blood cells. Since Lu gps are low abundant proteins, we speculate that their interaction with spectrin might be critical for signalling and receptor function rather than for participating in the linkage of the lipid bilayer to the red cell skeleton.

International audience; The Kochersberg loess area, west of Strasbourg (France), has been explored with the aim to reconstruct the Holocene landscape dynamics. Sediments, pollen and plant macro-remains were analysed from an organic rich sediment core, sampled in the thalweg of a small catchment. The several proxies are offering a multiscalar view of landscape evolution from the Neolithic to the Middle Age. At the catchment scale, major changes in the landscape are always associated with intense phases of occupation revealed by archaeological excavations. Résumé Impact anthropique du Néolithique au Moyen Âge : Approche pluridisciplinaire dans un bassin versant élémentaire du Kochersberg (Bas-Rhin, France) Le secteur loessique du Kochersberg, à l’ouest de Strasbourg, a été exploré dans le but de reconstruire les dynamiques du paysage au cours de l’Holocène. Les sédiments, le pollen et les macrorestes végétaux ont été extraits d’une carotte riche en matière organique prélevée dans le thalweg d’un bassin versant élémentaire. Les différentes archives offrent une vision multi-scalaire de l’évolution du paysage depuis le Néolithique jusqu’au Moyen Âge. A l’échelle du bassin versant, les changements importants du paysage sont toujours associés à des phases de forte implantation révélées par les fouilles archéologiques. http://quaternaire.revues.org/7047

We performed a high-resolution study of chironomid assemblages in a sediment core retrieved from Lake Igaliku in southern Greenland. The well-dated core is located within the former Norse Eastern Settlement and covered the last 1500 yr. The comparison of chironomid stratigraphy (PCA axis scores) with instrumental temperature data, land use history and organic matter in the sediment over the last 140 yr suggested that the primary changes in chironomid fauna in 1988 ± 2 yr were driven by the shift to modern agriculture in the catchment. This unprecedented change in chironomid fauna was most likely triggered by a shift in in-lake processes. Within the instrumental period, subtle variations in the chironomid assemblages that occurred before 1988 ± 2 yr were significantly correlated with summer temperatures even in times of traditional extensive sheep farming in the catchment. The relevance of the chironomid-derived climate signal over the last 1500 yr was supported by its good concordance with previous studies in west Greenland and in the Arctic. The chironomid assemblage therefore appeared to be a valuable proxy for climate changes within the Norse colony area. Synchronous changes in Norse diet and chironomid-reconstructed climate give new insights into the interplay of Norse society with climate.

Palaeoenvironmental studies from continental and marine sedimentary archives have been conducted over the last four decades in the archaeologically rich Norse Eastern Settlement in Greenland. Those investigations, briefly reviewed in this paper, have improved our knowledge of the history of the Norse colonization and its associated environmental changes. Although deep lakes are numerous, their deposits have been little used in the Norse context. Lakes that meet specific lake-catchment criteria, as outlined in this paper, can sequester optimal palaeoenvironmental records, which can be highly sensitive to both climate and/or human forcing. Here we present a first synthesis of results from a well-dated 2000-year lake-sediment record from Lake Igaliku, located in the center of the Eastern Settlement and close to the Norse site Garðar. A continuous, high-resolution sedimentary record from the deepest part of the lake provides an assessment of farming-related anthropogenic change in the landscape, as w...

High-molecular-weight (HMW) polycyclic aromatic hydrocarbons (PAHs) are pollutants that persist in the environment due to their low solubility in water and their sequestration by soil and sediments. The addition of a water-immiscible, nonbiodegradable, and biocompatible liquid, silicone oil, to a soil slurry was studied to promote the desorption of PAHs from soil and to increase their bioavailability. First, the transfer into silicone oil of phenanthrene, pyrene, chrysene, and benzo[a]pyrene added to a sterilized soil (sandy soil with 0.65% total volatile solids) was measured for 4 days in three two-liquid-phase (TLP) slurry systems each containing 30% (w/v) soil but different volumes of silicone oil (2.5%, 7.5%, and 15% [v/v]). Except for chrysene, a high percentage of these PAHs was transferred from soil to silicone oil in the TLP slurry system containing 15% silicone oil. Rapid PAH transfer occurred during the first 8 h, probably resulting from the extraction of nonsolubilized and of poorly sorbed PAHs. This was followed by a period in which a slower but constant transfer occurred, suggesting extraction of more tightly bound PAHs. Second, a HMW PAH-degrading consortium was enriched in a TLP slurry system with a microbial population isolated from a creosote-contaminated soil. This consortium was then added to three other TLP slurry systems each containing 30% (w/v) sterilized soil that had been artificially contaminated with pyrene, chrysene, and benzo[a]pyrene, but different volumes of silicone oil (10%, 20%, and 30% [v/v]). The resulting TLP slurry bioreactors were much more efficient than the control slurry bioreactor containing the same contaminated soil but no oil phase. In the TLP slurry bioreactor containing 30% silicone oil, the rate of pyrene degradation was 19 mg L(-)(1) day(-)(1) and no pyrene was detected after 4 days. The degradation rates of chrysene and benzo[a]pyrene in the 30% TLP slurry bioreactor were, respectively, 3.5 and 0.94 mg L(-)(1) day(-)(1). Low degradation of pyrene and no significant degradation of chrysene and benzo[a]pyrene occurred in the slurry bioreactor. This is the first report in which a TLP system was combined with a slurry system to improve the biodegradation of PAHs in soil.

International audience; Agriculture in southern Greenland has a two-phase history: with the Norse, who first settled and farmed the region between 985ad and circa 1450ad, and with the recent reintroduction of sheep farming (1920ad to the present). The agricultural sector in Greenland is expected to grow over the next century as anticipated climate warming extends the length of the growing season and increases productivity. This article presents a synthesis of results from a well-dated 1500-year lake sediment record from Lake Igaliku, south Greenland (61°00′N, 45°26′W, 15m asl) that demonstrates the relative impacts of modern and Norse agricultural activities. Pollen, non-pollen palynomorphs (NPPs), sediment mass accumulation rates, diatoms and stable isotopes of nitrogen provide a comprehensive history of both phases of agriculture and their associated impacts on the landscape and adjacent lake. The initial colonisation of southern Greenland is marked by a loss of tree birch pollen, a rise in weed taxa, and an increase in coprophilous fungi and sediment accumulation rate consistent with land-use changes. The biological and chemical proxies within the lake, however, show only slight changes in diatom taxa, and a rise in δ15N. After the Norse demise and during the Little Ice Age, most of the markers return to pre-settlement conditions. However, the continuation of non-indigenous plant taxa suggests that the landscape did not completely return to a pre-disturbance state. After 1988, the character of the lake changed markedly: mesotrophic diatoms and N isotopes all reveal major shifts consistent with a trophic shift, together with a sharp rise in sediment accumulation rate. The post-1988 lake environment, affected by modern farming development, is unprecedented within the context of the last 1500 years. These results demonstrate the potential of lake sediment studies paired with archaeological investigations to reveal the relationship between climate, environment and human societies.

International audience; This paper aims to reconstruct the vegetation history of a middle mountain – the Morvan (Burgundy, France) – since the Neolithic (i.e. 7000 years). The results of palynological and non-pollen palynomorphs (NPPs) analysis performed on 10 peat cores document the main phases of human agro-pastoral practices and natural resources management which drove the formation of the cultural landscape of the Morvan Massif over time. To document the history of human activities at a regional scale, particular attention was given to the determination, the characterization and the graphical depiction of phrases of human impact. Both the quantification of the impact of human pressure and the chronological uncertainty of the different phases identified by pollen and NPP analysis were taken into account. This study reveals a clear human presence during periods that were formerly poorly documented, such as the onset of the Neolithic period, the Bronze Age, the early Iron Age and the early Middle Ages. It also sheds new light over periods for which there is better archaeological and historical knowledge, such as the widespread occupation of the massif in the late Iron Age, the cultivation of chestnut from the 11th to the 16th century and the impact of modern firewood exploitation on the forest.

National audience

A multiproxy sedimentary record from Lake Igaliku in southern Greenland documents 1450 years of human impacts on the landscape. Diatoms, scaled chrysophytes, and C and N geochemistry show perturbations consistent with recent agricultural activities (post-ad 1980), superimposed upon long-term environmental variability. While the response to Norse agriculture (~ad 986–1450) is weak, the biological response to the last 30 years of modern sheep farming is marked, with drastic changes in diatom taxa, δ13C and δ15N isotopic ratios, and a sharp increase in scaled chrysophytes. Indeed, current conditions in the lake during the last 30 years are unprecedented in the context of the last 1450 years. The dominant driver for recent changes is likely an intensification of agricultural practices combined with warming summer temperatures. Warm temperatures and agricultural disturbance together during Norse Landnám did not lead to the marked changes seen in the modern lake environment over the last 30 years. The synergistic response between increased climate warming and agriculture will likely have unanticipated effects. These findings confirm the sensitivity of Arctic lakes to external anthropogenic forcing and are the first analyses of their kind for the effects of agriculture in Greenland.

International audience

Modern analogs are commonly used to investigate the relationships between modern pollen rain and the surrounding present vegetation and to improve our interpretation of fossil data. We collected modern pollen and spore rain in 18 more or less grazed and/or forested sites around Lake Saint-Point (Jura Mountains, France). Multivariate numerical techniques were applied to understand how modern pollen and non-pollen palynomorphs (NPP) taxa, collected in moss and dung samples, record local vegetation in the surroundings, and to identify indicators of tree cover or grazing. We show a strong relationship between current local herbaceous vegetation and pollen but underline the limits of past vegetation reconstructions based on AP/NAP ratio. In moss samples, we identified Picea, Abies, Fagus and Coollus pollen as well as Trichocladium, Kretschmaria deusta and Cirrenalia as indicators of tree cover. Spores of Sporormiella and some undetermined palynomorphs such as new NPP LCE-13 were positively correlated with openness while LCE-23 and LCE-32 could represent grazing indicators and/or coprophilous types. As compared to moss samples, dung samples contained much more pollen grains from Trifolium repens-type, Trifolium pratense-type, Plantago lanceolata-type and Plantago major/media-type taxa (grassland species eaten by cattle) and spores from coprophilous fungi. (C) 2012 Elsevier B.V. All rights reserved.

International audience

This paper presents quantitative climate estimates for the last millennium, using a multi-proxy approach with pollen and lake-level data from Lake Joux (Swiss Jura Mountains). The climate reconstruction, based on the Modern Analogue Technique, indicates warmer and drier conditions during the Medieval Warm Period (MWP). MWP was preceded by a short-lived cold humid event around AD 1060, and followed by a rapid return around AD 1400 to cooler and wetter conditions which generally characterize the Little Ice Age (LIA). Around AD 1450 (solar Spörer minimum), the LIA attained a temperature minimum and a summer precipitation maximum. The solar Maunder minimum around AD 1690 corresponded at Joux to rather mild temperatures but maximal annual precipitation. These results generally agree with other records from neighbouring Alpine regions. However, there are differences in the timing of the LIA temperature minimum depending on the proxy and/or the method used for the reconstruction. As a working hypothesis, the hydrological signal associated with the MWP and LIA oscillations at Lake Joux may have been mainly driven by a shift around AD 1400 from positive to negative NAO modes in response to variations in solar irradiance possibly coupled with changes in the Atlantic meridional overturning circulation.

International audience; Radiocarbon dating, pollen and non-pollen palynomorph analyses from a lake core were used to establish the timing and effects of farming activities around Lake Igaliku, Eastern Settlement, Greenland. The absence of agro-pastoral impact before the medieval colonization by Europeans provides an opportunity to understand the development of farming activity in a pristine landscape. The results show that the first phase of clearance and grazing pressure, without the expansion of the Norse apophyte (native plant, in habitats created by humans) Rumex acetosa type, could have occurred in the 9–10th century A.D. The presence of Norse settlers and livestock is clearly recorded from the 11–12th century A.D. with increasing frequencies of the Norse apophytes Rumex acetosa type and Ranunculus acris type, and coprophilous fungi. This colonization phase is followed by a period of decreasing human impact at the beginning of the 14th century, with a decrease in weeds, apophytes and coprophilous fungi suggesting a reduced grazing pressure. The regrowth of Salix and Betula and the disappearance of anthropogenic indicators except Rumex acetosa type between the 15th and 18th century demonstrate the abandonment of the settlement, until the development of contemporary agriculture in the 20th century.

International audience; This article presents a 241 cm long sediment record documenting the vegetation history using previous termpollen and non-pollennext term palynomorphs recovered from the Fénay marsh in Burgundy (Dijon area – previous termFrance). The pollen and non-pollennext term palynomorphs (NPP) record largely reflects intensive human influence (clearing, cultivation and grazing) on the surrounding area from the Late Bronze Age and Hallstatt period. La Tène period is marked by drier conditions and a substantial increase in Alnus. During the Gallo-Roman period, high values of Alnus decrease to the benefit of Quercus. In the Early Middle Ages (5th–10th C), the swamp becomes a temporary pond and Cerealia type and Secale are cultivated in this very open landscape. During the Late Middle Ages (13th–15th C), the temporary pond is transformed into a larger and deeper pond, used by the Cistercians for hydraulic power and perhaps as a hemp-retting pit. By the end of the 16th C, the pond had dried out and was used for the cultivation of cereal.

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International audience; Pollen analyses of three sediment cores performed on the archaeological lake dwellings of Chindrieux and Tresserve (Savoie, France), on the eastern shore of Lake Bourget, enable the reconstruction of vegetation history and human impact during the Bronze Age. Results show a good correlation between lake-level fluctuations and the evolution of anthropogenic indicators. The end of the Neolithic period and the early Bronze Age are characterised by a discreet occupation of the Lake Bourget surroundings, in spite of a warmer climatic condition. The middle Bronze Age, contemporaneous with wetter and cooler conditions, is related to a decrease in pollen of cultivated plants and weed. Farming activities reappear in the late Bronze Age and human impact increases suddenly at the very end of the late Bronze Age. Three anthropogenic phases are clearly visible: a short decrease in anthropogenic indicators and a high lake-level phase occur in the middle of this period of intense farming development. A new decrease in human impact appears at the beginning of the Iron Age.

International audience; In order to better understand the evolution of past climate-human-environment interactions in the North-western Alps during the Holocene, we have analysed the lipid content of two cores taken from the sediments of Lake le Bourget (French Alps). By using a specific molecular biomarker of Panicum miliaceum (broomcorn millet) previously defined and a new molecular marker of soil erosion, we demonstrate that the onset of millet cultivation coincides with the onset of major soils erosion in the catchment during the Middle Bronze Age. Although archaeological and archaeobotanical investigations indicate a discrete human occupation of the lakeshores at this period, they also point to a regional change in agricultural practices that deeply affected soils. The evolution of millet cultivation appears in strong connection with climatic variations, estimated in the same cores from the variations in titanium, a proxy of hydrological changes in the region. Social and cultural triggers cannot be discarded at this stage. Such an approach applied to more sedimentary archives shows high potential to unravel the temporal and spatial dynamics of human land-use.

International audience; Vegetation and lake-level data from the archaeological site of Tresserve, on the eastern shore of Lake Le Bourget (Savoie, France), are used to provide quantitative estimates of climatic variables over the period 4000-2300 cal BP in the northern French Pre-Alps, and to examine the possible impact of climatic changes on societies of the Bronze and early Iron Ages. The results obtained indicate that phases of higher lake level at 3500-3100 and 2750-2350 cal BP coincided with major climate reversals in the North Atlantic area. In west-central Europe, they were marked by cooler and wetter conditions. These two successive events may have affected ancient agricultural communities in west-central Europe by provoking harvest failures, more particularly due to increasing precipitation during the growing season. However, archaeological data in the region of Franche-Comté (Jura Mountains, eastern France) show a general expansion of population density from the middle Bronze Age to the early Iron Age. This suggests a relative emancipation of proto-historic societies from climatic conditions, probably in relation to the spread of new modes of social and economic organisation.

International audience

This paper presents results obtained from two sediment sequences taken from Lake Joux (1006 m a.s.l.) in the Swiss Jura Montains and Lake Anterne (2060 m a.s.l.) in the French northern Alps to document past variations in climatic parameters over the last two millennia. A high-resolution study of the Lake Joux sediment sequence (ca 10 yr/sample) allows the establishment of a lake-level record spanning the last millennium. The Little Ice Age appears to have been characterised by increasing humidity, while the Medieval Warm Period and the post-industrial warm phase corresponded to lower lake levels. A comparison between the Joux lake-level and solar irradiance records suggests that variations in solar activity may have been a major forcing factor of climatic oscillations over the last millennium. A high-resolution analysis (20 yr/sample) of the Chironomidae assemblages in a core from Lake Anterne provides quantitative estimates of past variations in July temperature over the last 1800 years. Three ca 1.5°C cooling phases were recognised at ca 480-680, ca 1150, and after ca 1350 AD (i.e. during the Little Ice Age). These results appear to be consistent with other palaeoclimatic records established in the Swiss Alps from fluctuations of the Great Aletsch Glacier and from densitometry studies of Larix subfossile trunks. Finally, the possible impact of climatic oscillations on the past human societies is discussed., Cet article présente les résultats obtenus à partir de l 'étude de deux séquences sédimentaires prélevées la première au lac de Joux (1006 m) dans le Jura suisse, et la seconde au lac d'Anterne (2060 m) dans les Alpes françaises du Nord, pour documenter les variations des paramètres climatiques au cours des deux derniers millénaires. L 'analyse à haute résolution de la séquence sédimentaire du lac de Joux (environ 10 ans/échantillon) a permis l 'établissement d'une courbe de variations du plan d'eau au cours des derniers 1000 ans. Le Petit Age Glaciaire apparaît caractérisé par une augmentation de l'humidité, tandis que l'Optimum climatique médiéval et le réchauffement post-industriel correspondent à de bas niveaux lacustres. Une comparaison entre les variations du niveau du lac de Joux et celles de l'irradiance solaire suggère que les variations de l 'activité solaire ont pu être un forçage majeur du climat au cours du dernier millénaire. L 'analyse à haute résolution (20 ans/échantillon) de la séquence du lac d'Anterne a permis d 'établir une courbe des variations des températures de juillet pour les dernières 1800 années. Trois phases de refroidissement (environ 1,5°C) ont été reconnues vers AD 480-680, AD 1150, et après AD 1350 (Petit Age Glaciaire). Ces résultats paraissent en accord avec d'autres enregistrements paléoclimatiques établis dans les Alpes suisses à partir des fluctuations du Grand Glacier d'Aletsch, et à partir de l'analyse densitométrique de troncs subfossiles de mélèzes. Enfin, est discuté l'impact possible de ces oscillations du climat sur les sociétés passées., Magny Michel, Millet Laurent, Arnaud Fabien, Desmet Marc, Gauthier Emilie, Heiri Oliver, Vannière Boris, Verneaux Valérie. Variations du climat au cours des deux derniers millénaires : deux cas d'étude dans le Jura et les Alpes du Nord. In: Collection EDYTEM. Cahiers de géographie, numéro 6, 2008. Du climat à l’homme, dynamique holocène de l’environnement dans le Jura et les Alpes. pp. 51-64.

International audience; During the Viking Age (ca AD 800-1100) Scandinavian explorers settled the islands of the western North Atlantic, making the northernmost agricultural area of the medieval period. Expansion to south-west coast of Greenland at the end of the tenth century brought Norse settlers closer to the limits of their European-style agricultural systems. In response to the harsh low arctic climate, the Greenland Norse have adapted their farming strategies and changed their subsistence pattern, giving a more important place to hunting and fishing. This evolution had probably been accelerated by climatic changes of the Little Ice Age. A good knowledge of the Greenland Norse economy by means of historical and archaeological literature is necessary for the interpretation of sedimentary archives, witness of human land use, its impact upon the environment and its evolution from settlement to abandonment. The first results indicate the impact of Norse agriculture upon the local vegetation.; L’exploration des îles de l’Atlantique nord au cours des ixe, xe et xi e siècles par les populations scandinaves a conduit à la formation du front pionnier agricole le plus septentrional de l’époque médiévale. la colonisation de la côte sud-ouest du Groenland, milieu aux conditions climatiques extrêmes, par des agriculteurs islandais puis norvégiens de 986 Ad au milieu du xv e siècle, va fournir l’exemple de la limite de l’agropastoralisme en contexte arctique. Face à la rigueur du climat, les colons scandinaves devront adapter leurs pratiques agriculturales et se tourner de plus en plus vers la chasse et la pêche pour leur alimentation, conversion probablement accélérée par la dégradation des conditions climatiques au cours du petit Âge Glaciaire. une bonne connaissance de ces pratiques par le biais des textes historiques et de l’archéologie est nécessaire à l’interprétation des archives sédimentaires témoins de l’activité agricole, de son impact sur l’environnement et de son évolution. les premiers résultats paléoenvironnementaux précisent l’impact de cette agriculture sur le couvert végétal local.

Pollen studies carried out over the last years in the Jura Mountains allow to reconstruct the regional history of the vegetation and human impact during the last 8 millennia. Successive phases of increasing and decreasing human impact have been recognised. The first pollen evidence of human impact occurred in the Early Neolithic period (6th millennium BC). Marks of human impact appear to have been relatively weak during the Early Bronze age, and nearly absent during the Middle Bronze age. They show a clear increase at ca 1000 cal BC during the Final Bronze age. The picture is more difficult to outline for the Iron age due to problems inherent in radiocarbon dating. During the Gallo-Roman period, the increase in human impact appears to be different depending on considered altitude. The transition between Antiquity and Medieval Times coincided with a decrease in human impact, which, once again, increased during the 7th century and more particularly the 8th century. Around 1000 AD, forested areas underwent a clear retreat. After wars and epidemics which characterised the 14th century, the 15th century marked a new increase in human impact, responsible for a quasi-disappearance of forests on the Jura Mountains., Les analyses polliniques effectuées ces dernières années sur le Jura permettent de retracer l 'évolution de la végétation et des impacts anthropiques au cours des huit derniers millénaires. Les phases successives d'emprises et de déprises agricoles sont maintenant assez bien connues. Les premiers indices polliniques d'anthropisation apparaissent dès le Néolithique ancien, soit le VIe millénaires avant notre ère et se stabilisent souvent à partir Ve millénaire. La faible emprise du Bronze ancien est suivie d'une déprise agricole couvrant une bonne partie du Bronze Moyen, sinon sa totalité. Il faut attendre le début du premier millénaire avant J.-C. pour voir apparaître une forte emprise agricole qui marquera la presque totalité du Bronze final. L 'âge du Fer reste plus difficile à cerner surtout parce qu 'il est difficile d 'obtenir des dates radiocarbone précises pour cette période. L 'époque gallo-romaine voit le retour d'un signal pollinique homogène montrant une emprise agricole plus ou moins importante selon l'altitude. La déprise de la transition entre l 'époque gallo-romaine et le Haut Moyen-Age illustre une fois de plus la non linéarité de ces processus. Il faut attendre le VIIe siècle, et surtout le VIIIe siècle, pour voir réapparaître un signal anthropique régulier, et arriver aux alentours de l 'an Mil pour constater un net recul de l 'espace forestier. Le cortège de guerres et d'épidémies du XIVe siècle sonne le glas de la prospérité agricole médiévale. Le renouveau qui se dessine à l 'orée du XVe siècle correspond à une nouvelle phase d 'emprise agricole jusque là inégalée et qui verra la quasi disparition des forêts du Massif jurassien. Une réflexion a été engagée sur l 'origine de cette succession de phases d 'emprises et de déprises agricoles. Il apparaît qu 'il s 'agit d 'une combinaison complexe de facteurs sociaux-économiques et climatiques., Gauthier Emilie, Richard Hervé. L'anthropisation du Massif jurassien : bilan des données palynologiques. In: Collection EDYTEM. Cahiers de géographie, numéro 6, 2008. Du climat à l’homme, dynamique holocène de l’environnement dans le Jura et les Alpes. pp. 273-280.

Lu (Lutheran) blood group and BCAM (basal cell adhesion molecule) antigens both reside on two gp (glycoprotein) isoforms, Lu and Lu(v13), that differ by the size of their cytoplasmic tail. They are receptors of laminin-10/11 and are expressed in RBCs (red blood cells), epithelial cells of multiple tissues and vascular endothelial cells. To gain more insights into the biological function of Lu/BCAM gps, we looked for potential partners of their cytoplasmic tail. We isolated Ubc9 (ubiquitin-conjugating enzyme 9) protein by screening a human kidney library using the yeast two-hybrid system. Lu/Ubc9 interaction was validated by GST (glutathione S-transferase) pull-down and co-immunoprecipitation experiments. Endogenous Ubc9 formed a complex with endogenous or recombinant Lu gp in A498 and MDCK (Madin–Darby canine kidney) epithelial cells respectively. Replacement of Lys585 by alanine in the Lu gp abolished in vitro and ex vivo interactions of Lu gp with Ubc9 protein. Lu K585A mutant transfected in MDCK cells exhibited a normal basolateral membrane expression but was overexpressed at the surface of polarized MDCK cells as compared with wild-type Lu. Pulse–chase experiments showed extended half-life of Lu K585A gp at the plasma membrane, suggesting an impaired endocytosis of this mutant leading to protein accumulation at the membrane. Furthermore, we showed that the ability of MDCK-Lu K585A cells to spread on immobilized laminin was dramatically decreased. Our results support a physiological role for the direct interaction between Lu gp and Ubc9 protein and reveal a role for this enzyme in regulating the stability of Lu gp at the cell membrane.

Die Rückschlüsse aus unserer Fallstudie zum Tal der Laigne stellen die Stichhaltigkeit der geoarchäologischen Methode heraus, die auf zwei Ebenen der Untersuchung Anwendung fand. In einem ersten Schritt werden, auf die Gesamtheit der Schwemmebene bezogen, die allgemeinen Daten ermittelt, anhand derer sich die spezifische Funktionsweise dieses Fluβsystems während des Holozäns charakterisieren läβt (Bestimmung von Sedimentabfolgen, Vegetationsentwicklung und Besiedlungsphasen). In einem zweiten Schritt steht die lokale Gegenprobe im Vordergrund. Dabei geht es um die Identifizierung und möglichst exakte Datierung der Interaktionen zwischen Naturgeschehen und menschlichen Aktivitäten, die letztlich über die Veränderungsprozesse im gesamten Fluβsystem Aufschluβ geben. Damit wird der allesentscheidende Einfluβ des Menschen auf die alluviale Sedimentation im Verlauf des 1. Jahrh. n. Chr. deutlich herausgestellt., The conclusions from the research project in the Laigne valley show the relevance of the geoarchaeological approach conducted on two scales of investigation. The first, over the entire alluvial plain, allows general data to be collected which characterise the specific functions of each catchment basin during the Holocene period : determination of sedimentary sequences, evolution of vegetation and phases of human occupation. The second is a geoarchaeological approach on the scale of a test site : it demonstrates and dates as precisely as possible interactions between natural events and human activities which reveal changes to the entire catchment basin., Les conclusions issues de l’expérience menée dans la vallée de la Laigne mettent en évidence la pertinence de la démarche géoarchéologique menée à deux échelles d’investigation. La première, conduite sur l’ensemble de la plaine alluviale, permet de recueillir les données générales qui caractérisent le fonctionnement spécifique de ce bassin versant pendant la période holocène : détermination des séquences sédimentaires, végétales et des phases d’occupation. La seconde est celle d’une démarche géoarchéologique menée à l’échelle d’un site-test : elle met en évidence et date le plus précisément possible des interactions entre événements naturels et activités humaines, interactions révélatrices des mutations de l’ensemble du bassin versant. Le contrôle anthropique de la sédimentation alluviale au cours du Ier s., c’est-à-dire lors de la phase de romanisation de ce terroir, est ainsi clairement mis en évidence., Petit Christophe, Camerlynck Christian, Deweirdt Eline, Durlet Christophe, Garcia Jean-Pierre, Gauthier Emilie, Ollive Vincent, Richard Hervé, Wahlen Patrice. Géoarchéologie du site antique de Molesme en vallée de Laigne (Côte-d’Or) : mise en évidence de l’impact anthropique sur la sédimentation alluviale. In: Gallia, tome 63, 2006. pp. 263-281.

International audience

International audience; The Rumanian site of Poiana Slatinei at Lunca (Neamt), excavated regularly by G. Dumitroaia and his team since 1984, is the earliest evidence of salt production in Europe. It is a unique site in Europe where a stratified accumulation of ash, charcoal and burned soil – 60 metres long by 25 meters wide – has been preserved. This site is close to a highly concentrated salt spring which is still in use, and includes tens, not to say hundreds of stratified combustion layers which form an accumulation of 2,80 meters maximal height. Thanks to the numerous painted shards, this evidence for the production of salt has been dated, since the beginning, to the Early Neolithic, and more precisely to the Starcevo-Cris IIIb-IVa. In 2004, the test excavation opened in 2002 at the centre of the accumulation was enlarged to 20 m2, allowing the Franco-Rumanian team to draw systematically to the last detail the stratigraphical levels and to sample soil, charcoal and pollen in order to improve the understanding of pace and intensity of the production, the used techniques, as well as managing and interaction with the environment. Up to present 10 calibrated radiocarbon AMS dates confirm the antiquity of this exploitation which is broadly dated to 6050 to 5500 BC, as well as the preliminary results of the paleoenvironmental analyses (micromorphology, anthracology, and palynology) allow us to envisage a salt production without pottery, complementary with other activities such as breeding.; Le site roumain de Poiana Slatinei à Lunca (Neamt), fouillé régulièrement par G. Dumitroaia et son équipe depuis 1984, représente les plus anciens témoins de production de sel en Europe. Il s'agit d'un site unique en Europe où un amas stratifié de cendres, de charbons et de sols rubéfiés, long de 60 m et large de 25 m a été conservé. Situé à proximité immédiate d'une source salée toujours utilisée et fortement concentrée, il renferme plusieurs dizaines, sinon centaines, de sols de combustion stratifiés qui forment cet important amas sur près de 3 m de haut. Grâce aux nombreux fragments de céramique peinte, ces témoins de production de sel ont dès le début été datés du Néolithique ancien, et plus précisément du Starcevo-Cris IIIb-IVa. En 2004, l'élargissement à 20 m2 du sondage central ouvert en 2002 sur le sommet du dépôt allait permettre à l'équipe franco-roumaine de réaliser des relevés détaillés systématiques des différentes coupes stratigraphiques et des prélèvements (sols, charbons, grains de pollen) destinés à mieux caractériser les vitesses et les intensités de production, les techniques utilisées, les modes de gestion et les interactions avec le milieu naturel. Aujourd'hui, nous disposons de 10 datations radiocarbone AMS calibrées qui confirment bien l'ancienneté de ces exploitations datées, au plus large, entre 6050 à 5500 avant J.-C., ainsi que des premiers résultats des analyses paléo-environnementales (micromorphologie, anthracologie et palynologie) qui permettent d'envisager une production de sel sans récipient, complémentaire d'autres activités comme l'élevage.

International audience; Cet article présente les résultats de l'analyse du remplissage sédimentaire de plusieurs paléoméandres holocènes conservés à la surface de la plaine alluviale du Rhône dans le secteur des Basses Terres, secteur situé à 70 km en amont de Lyon. L'objectif est d'identifier les fluctuations paléohydrologiques du Rhône et d'en déterminer les causes (contrôles locaux, anthropiques, climatiques). Les premiers résultats montrent une pa-renté certaine des modes d'alluvionnement entraînant le colmatage des paléoméandres, avec une succession de dépôts alluvionnés par décantation ou par des courants tractifs (suspensions uniformes), ainsi que le développement de séquences organo-minérales dans la partie supérieure du rem-blaiement. On observe néanmoins une grande diversité de détails dans la nature des dépôts et leur répartition au sein des sondages (limons massifs ou microlaminés, limon organique, tourbe, tuf). Les vitesses d'alluvionnement distinguent deux ensembles de paléoméandres, avec des taux de l'ordre de 2,5 mm/an (Atlantique récent et Subboréal) et 6,5 mm/an (Subboréal et Subatlantique). Dans le paléoméandre des Marais, la confrontation des données issues de la susceptibilité magnétique, de la palynologie et de l'analyse granulométrique met en évidence deux périodes de forte ac-tivité hydrologique, centrées sur le début de l'Epoque romaine et le Haut-Moyen-Age. Mots-clés : paléochenal, plaine alluviale, paléoenvironnement, Rhône, Holocène. ABSTRACT SEDIMENTARY FILLINGS STUDY OF THE HOLOCENE RHÔNE RIVER PALAEOMEANDERS ON THE BASSES TERRES FLOODPLAIN (ISÈRE, AIN, FRANCE) This paper points out the results on the sedimentary fill of a set of former wandering meanders that have been preserved in the Upper Rhône river alluvial plain (Basses Terres floodplain), 50 km upstream from Lyon. The objective is to attempt the reconstruction of the hydrosedimentary fluctuations of the river and their origin. Modes of sediment fills vary from one palaeomeander to the other but common features can be found. Fine silt deposits occur during the first phases by processes of mineral decantation in an open area or by tractive currents (uniform suspension). Organic layers are interstratified with silty layers in the infill's upper part. Nevertheless, detailed stratigraphical studies specify the diversity of palaeomeander fills (homogeneous or micro-laminated silts, organic silt, gyttja, peat, tufa). Accumulation rates within the cutoffs vary from 2,5 mm yr-1 (recent Atlantic and Subboreal palaeomeanders) to 6 mm yr-1 (Subboreal and Subatlantic palaeomeanders). Informations given by magnetic susceptibility, palynology and grain-size characteristics of sediments analysis in the Marais palaeochannel point out two phases of high fluvial activity, during the beginning of the Gallo-Roman period and during the Dark Ages.

The conclusions from the research project in the Laigne Valley show the relevance of the geoarchaeological approach conducted on two scales of investigation. The first, over the entire alluvial plain, allows general data to be collected which characterise the specific functions of each catchment basin during the Holocene period : determination of sedimentary sequences, evolution of specific functions of each catchment basin during the Holocene period : determination of sedimentary sequences, evolution of vegetation and phases of human occupation. The second is a geoarchaeological approach on the scale of a test site: it demonstrates and dates as precisely as possible, interactions between natural events and human activities, which reveal changes to the entire catchment basin., Les conclusions issues de l'expérience menée dans la vallée de Laigne mettent en évidence la pertinence de la démarche géoarchéo-logique menée à deux échelles d'investigation. La première, conduite sur l'ensemble de la plaine alluviale, permet de recueillir les données générales qui caractérisent le fonctionnement spécifique de ce bassin-versant pendant la période holocène : détermination des séquences sédimentaires, végétales et des phases d'occupations humaines. La seconde est celle d'une démarche géoarchéologi-que menée à l'échelle d'un site-test : elle met en évidence et date de la façon la plus précise possible des interactions entre événe-ments naturels et activités anthropiques, interactions révélatrices des mutations de l'ensemble du bassin-versant.

The pollen analysis of a borehole from the Laigne Valley, in Molesme (21), gives the first complete Holocene reference for the southeast of the Paris Basin. This low altitude sequence differs from those obtained in mid-mountainous regions: the pine forest is not replaced by oak and beech woods until the end of the Atlantic chronozone. Certain fluctuations which reveal changes in humidity in the alluvial plain, also shown by malacological analyses on a nearby outcrop, could be the result of more global climatic changes. The first palynological clues to anthropisation do not appear until the Iron Age, and fit perfectly with local archaeological data., L'analyse pollinique d'un forage réalisé dans la vallée de la Laigne, sur la commune de Molesme (21), permet d'obte-nir la première référence holocène pour le Sud-Est du Bassin de Paris. Cette séquence de basse altitude montre des dif-férences avec celles qui sont obtenues dans les régions de moyenne montagne : le remplacement de la forêt de pin par une chênaie-hêtraie ne se fait notamment qu'à la fin de l'Atlantique. Certaines fluctuations traduisant des changements d'humidité de la plaine alluviale mis en évidence également par les analyses malacologiques faites sur une coupe pro-che, pourraient être la conséquence de variations climatiques plus globales. Les premiers indices palynologiques d'an-thropisation n'apparaissent qu'à l'âge du Fer et sont parfaitement en accord avec les données archéologiques locales.

Lutheran (Lu) and Lu(v13), two glycoprotein (gp) isoforms belonging to the immunoglobulin superfamily, represent adhesion molecules that act as erythrocyte receptors for laminin 10/11. These two gps, which differ only by the length of their cytoplasmic tail, carry both Lu blood group and Basal Cell Adhesion Molecule (B-CAM) antigens. Here, analysis of the Triton extractability of recombinant Lu and Lu(v13) gps in K562 transfected cells showed that both gps were mainly associated with the detergent-insoluble material. Patching experiments using Cholera Toxin subunit B indicated that Lu gps were not localized in lipid rafts. Glutathione-S-transferase capture assays showed that the cytoplasmic domain of Lu and Lu(v13) bound to erythroid spectrin, present in a low ionic strength extract from red cell ghosts. Direct interaction with spectrin was confirmed by plasmon resonance assays. Site-directed mutagenesis mapped a major interaction site with spectrin to the RK573-574 motif, located on the cytoplasmic tail of Lu gp, in close vicinity to the inner leaflet of the membrane lipid bilayer. The two Lu adhesion gps represent the first example of a direct link between transmembrane proteins and spectrin in red blood cells. Since Lu gps are low abundant proteins, we speculate that their interaction with spectrin might be critical for signalling and receptor function rather than for participating in the linkage of the lipid bilayer to the red cell skeleton.

Palaeoenvironmental and archaeological investigations have been in progress since 2 years, 70 km upstream from Lyon, in the upper Rhône valley. A multi-disciplinary team (palaeogeography, palaeoecology, archaeology) is attempting to reconstruct the spatio-temporal fluctuations of the nver and their origin through the survey of meandering palaeochannels A first spatial approach allowed us to identify several meanders Phases of channel change are identified from the recent Atlantic penod until the Subatlantic penod (Modern Times). Detailed stratigraphical study of 6 palaeomeander fills is undertaken Cores have been taken from pool fills units, up to the sandy-gravel bottom (6 meters m depth on the average), for palaeoenvironmental analysis. A chronological framework has been established (14C dating, palynology). The first results provide new information on fluvial dynamics and allow us to propose a reconstruction of the Basses Terres floodplain evolution during the Holocene Some archaeological investigations have been earned out m the alluvial plain. The goal is to assess the human activities pressure on the sector and their impact on the environment., Des investigations paléoenvironnementales et archéologiques sont entreprises depuis 2 ans dans la plaine alluviale du Haut-Rhône, à 70 km en amont de Lyon. Une équipe pluri-disciplinaire (paléogéographie, paléoécologie, archéologie) est rassemblée dans le cadre d'un programme collectif de recherche (PCR) intitulé " Peuplement et milieux en Bas-Dauphiné ". L'objectif est d'identifier les fluctuations morphologiques et paléohydrologiques du Rhône et d'en déterminer les causes (contrôles locaux, anthropiques, climatiques). L'étude repose en partie sur l'analyse d'une série de paléoméandres conservés à la surface de la plaine alluviale. Une approche cartographique a permis de reconnaître plusieurs méandres recoupés depuis l'Atlantique récent jusqu'au Subatlantique (époque moderne). Une analyse systématique des paléoméandres est en cours de réalisation. Le colmatage sédimentaire et organique de 6 paléochenaux fait l'objet d'analyses détaillées. Un cadre chronologique est en cours d'établissement (datations radiocarbone, palynologie). Les premiers résultats montrent une parenté certaine des modes d'alluvionnement présidant au colmatage des paléoméandres mais aussi une grande diversité de détail. Ils apportent de nouvelles informations sur la dynamique fluviale de ce secteur Une reconstitution de l'édification holocène de la plaine alluviale est proposée. Cette approche est couplée à des investigations archéologiques, dans le but d'évaluer l'importance de l'activité humaine sur le secteur et les interrelations avec le fleuve., Salvador Pierre Gil, Berger Jean François, Gauthier Emilie, Vannière Boris. Holocene fluctuations of the Rhône river in the alluvial plain of the Basses Terres (Isère, Ain, France) [ Fluctuations du Rhône à l'Holocène dans la plaine alluviale de Basses Terres (Isère, Ain, France).]. In: Quaternaire, vol. 15, n°1-2, 2004. Fluvial Archives Group. Clermond-Ferrant 2002. pp. 177-186.

International audience; Geochemical and particle size analyses, surface scanning magnetic susceptibility, microscopic charcoal counting and pollen analysis, have been carried out on two cores from the lower Doubs valley in order to reconstruct the land use history. The interpretation of anthropogenic pollen indicators and micro-charcoal deposits is discussed in relation to the lithological variation of sedimentary accumulation and evolution of the settlement. The environmental changes which occurred during the 1st and the 6th century AD reflect the impact of human activities on the landscape in the immediate surroundings of the site. Multiproxy indicators indicate that soil erosion as a consequence of agricultural activities including fire practices. A reactivation of hydrologic flow of the river recorded in the sedimentary sequences attests to a larger environmental perturbation between 1st-3rd and 7th-8th century AD.

The settlement of the second plateau, in the Jura range (above 700 meters altitude), remains dubious until Xle century, for lack of archaeological or textual data sufficient. In order to answer uncertainties, as well geographical as chronological, palynological analysis, performed in two peat bogs, allowed to reconstitute the fluctuations of human influence on vegetation since the Iron Age. Anthropogenic indicators show that this zone was populated during Protohistory Human impact increases slightly during Gallo-Roman period Regression of human influence is recorded at the transition between the Lower Empire and the Early Middle Age Human activities reappear in a stable way and forest clearings emphasize from Xle century. A last agricultural crisis is perceived in XlVe century, consequence of the various disorders, which strike the area at this time. The recovery started in XVe century involves an overexploitation of environment, Le peuplement du deuxième plateau du massif jurassien (au-dessus de 700 mètres d'altitude) reste incertain jusqu'au Xle siècle, faute de données archéologiques ou de sources textuelles suffisantes. Afin de répondre aux incertitudes, tant géographiques que chronologiques, deux analyses palynologiques, s'attachant plus particulièrement à l'étude des indices polliniques d'anthropisation, ont permis de reconstituer les fluctuations des développements agropastoraux depuis l'Age du Fer, dans la partie centrale du massif. Contrairement à ce que semblent indiquer les cartes archéologiques et les textes anciens, cette zone fût irrégulièrement - mais indubitablement - peuplée au cours de la Protohistoire. L'impact anthropique augmente légèrement durant la période gallo-romaine. Après une deprise à la transition entre le Bas-Empire et le Haut Moyen Age, les activités agropastorales réapparaissent de manière stable et les défrichements s'amplifient nettement à partir du Xle siècle. Une dernière deprise agricole est visible au XlVe siècle, conséquence de la conjugaison des troubles divers qui frappent la région à cette époque. La reprise amorcée au XVe siècle entraîne une surexploitation du milieu., Gauthier Emilie. Evolution des activités agropastorales du Haut Jura (France) au cours des trois derniers millénaires. In: Quaternaire, vol. 13, n°2, 2002. pp. 137-147.