Showing papers by "University of Montpellier published in 1997"
TL;DR: In this paper, the use of isolation by distance models as a basis for the estimation of demographic parameters from measures of population subdivision was re-examined, and the results for values of F-statistics in one-dimensional models and coalescence times in 2D models were provided.
Abstract: I reexamine the use of isolation by distance models as a basis for the estimation of demographic parameters from measures of population subdivision. To that aim, I first provide results for values of F-statistics in one-dimensional models and coalescence times in two-dimensional models, and make more precise earlier results for F-statistics in two-dimensional models and coalescence times in one-dimensional models. Based on these results, I propose a method of data analysis involving the regression of F(ST)/(1 - F(ST)) estimates for pairs of subpopulations on geographic distance for populations along linear habitats or logarithm of distance for populations in two-dimensional habitats. This regression provides in principle an estimate of the product of population density and second moment of parental axial distance. In two cases where comparison to direct estimates is possible, the method proposed here is more satisfactory than previous indirect methods.
3,331 citations
TL;DR: In this article, it was shown that the growth mechanism for SWNTs must be independent of the details of the technique used to make them, and that the ready availability of large amounts of SWNT can make them much more accessible for further study.
Abstract: Single-walled carbon nanotubes (SWNTs) offer the prospect of both new fundamental science and useful (nano)technological applications1. High yields (70–90%) of SWNTs close-packed in bundles can be produced by laser ablation of carbon targets2. The electric-arc technique used to generate fullerenes and multi-walled nanotubes is cheaper and easier to implement, but previously has led to only low yields of SWNTs3,4. Here we show that this technique can generate large quantities of SWNTs with similar characteristics to those obtained by laser ablation. This suggests that the (still unknown) growth mechanism for SWNTs must be independent of the details of the technique used to make them. The ready availability of large amounts of SWNTs, meanwhile, should make them much more accessible for further study.
2,568 citations
TL;DR: Reactive astrocytes should be considered a key element, like neurons, of a dynamic environment, thus forming with neurons a functional unit involved in homeostasis, plasticity and neurotransmission.
1,773 citations
TL;DR: IMGT goals are to establish a common data access to all immunogenetics data, including nucleotide and protein sequences, oligonucleotide primers, gene maps and other genetic data of Ig, TcR and MHC molecules, and to provide a graphical user friendly data access.
Abstract: IMGT, the international ImMunoGeneTics database, is an integrated database specialising in Immunoglobulins (Ig), T cell Receptors (TcR) and Major Histocompatibility Complex (MHC) of all vertebrate species, created by Marie-Paule Lefranc, CNRS, Montpellier II University, Montpellier, France (lefranc@ligm.crbm.cnrs-mop.fr). IMGT includes three databases: LIGM-DB (for Ig and TcR), MHC/HLA-DB and PRIMER-DB (the last two in development). IMGT comprises expertly annotated sequences and alignment tables. LIGM-DB contains more than 23 000 Immunoglobulin and T cell Receptor sequences from 78 species. MHC/HLA-DB contains Class I and Class II Human Leucocyte Antigen alignment tables. An IMGT tool, DNAPLOT, developed for Ig, TcR and MHC sequence alignments, is also available. IMGT works in close collaboration with the EMBL database. IMGT goals are to establish a common data access to all immunogenetics data, including nucleotide and protein sequences, oligonucleotide primers, gene maps and other genetic data of Ig, TcR and MHC molecules, and to provide a graphical user friendly data access. IMGT has important implications in medical research (repertoire in autoimmune diseases, AIDS, leukemias, lymphomas), therapeutical approaches (antibody engineering), genome diversity and genome evolution studies. IMGT is freely available at http://imgt.cnusc.fr:8104
996 citations
TL;DR: In this article, the authors focus on the Santonian compressional event, which occurred during the late Santonian tectonism, and interpret these phenomena as causally related aspects of a global tectonic event.
444 citations
TL;DR: In this paper, the chemistry of various non-hydrolytic sol−gel processes including hydroxylation in nonaqueous systems and aprotic condensation reactions are surveyed.
Abstract: This review surveys the chemistry of various nonhydrolytic sol−gel processes including hydroxylation in nonaqueous systems and aprotic condensation reactions. Some examples of applications in the field of single and multicomponent oxides demonstrate the interest of these approaches as alternatives to the usual hydrolytic routes. More particularly nonhydrolytic methods lead to improved control over the molecular level homogeneity and stoichiometry of multicomponent oxides.
440 citations
TL;DR: Three members of a new family of antimicrobial peptides from the hemolymph of shrimpsPenaeus vannamei in which immune response has not been experimentally induced display antimicrobial activity against fungi and bacteria with a predominant activity against Gram-positive bacteria.
436 citations
TL;DR: It is shown that the 14q+ translocation represents a t(6;14)(p25;q32) and that this aberration is recurrent in MM, as it was found in two of eleven MM cell lines.
Abstract: The pathogenesis of multiple myeloma (MM), an incurable tumour causing the deregulated proliferation of terminally differentiated B cells, is unknown1. Chromosomal translocations (14q1) affecting band 14q32 and unidentified partner chromosomes are common in this tumour, suggesting that they may cause the activation of novel oncogenes2,3. By cloning the chromosomal breakpoints in an MM cell line, we show that the 14q+ translocation represents a t(6;14)(p25;q32) and that this aberration is recurrent in MM, as it was found in two of eleven MM cell lines. The translocation juxtaposes the immunoglobulin heavy-chain (IgH) locus to MUM1 (multiple myeloma oncogene 1)lIRF4 gene, a member of the interferon regulatory factor (IRF) family known to be active in the control of B-cell proliferation and differentiation. As a result, the MUM1/IRF4 gene is overexpressed—an event that may contribute to tumorigenesis, as MUM1/IRF4 has oncogenic activity in vitro. These findings identify a novel genetic alteration associated with MM, with implications for the pathogenesis and diagnostics of this tumour.
344 citations
TL;DR: The analysis of the partitioning based on the coral variables suggests that there are significant relationships between benthic and fish assemblages.
Abstract: The objective of this work is to identify which substrata characteristics (such as coral morphology, coral diversity, coral species richness, percentage coverage by live coral or by algae) influence the structure and abundance of fish communities. The study was carried out at Reunion Island, Indian Ocean, where six sites were sampled in two zones (reef flat and outer reef slope). Quantitative data were collected by visual census techniques, along a linear transect of 50 m for the substratum, and a belt of 50×2 m for the fish communities. Correspondence analysis (CA) and an optimising cluster analysis, called dynamic clustering method (DCM) were used to describe and compare fish assemblages with the benthic composition. The relationships between benthic and fish communities were examined using the classes revealed by the partitioning of the substratum with DCM. This partitioning allowed us to derive four classes of substratum: the non-disturbed reef flat, the non-disturbed outer reef slope, the perturbed reef habitat and the reef pass. The analysis of the partitioning based on the coral variables suggests that there are significant relationships between benthic and fish assemblages.
306 citations
TL;DR: It is demonstrated that ezrin is a major AKAP in gastric parietal cells and may function to tether type II A‐kinase to a region near the secretory canaliculus.
Abstract: cAMP‐dependent protein kinase (A‐kinase) anchoring proteins (AKAPs) are responsible for the subcellular sequestration of the type II A‐kinase. Previously, we identified a 78 kDa AKAP which was enriched in gastric parietal cells. We have now purified the 78 kDa AKAP to homogeneity from gastric fundic mucosal supernates using type II A‐kinase regulatory subunit (RII) affinity chromatography. The purified 78 kDa AKAP was recognized by monoclonal antibodies against ezrin, the canalicular actin‐associated protein. Recombinant ezrin produced in either Sf9 cells or bacteria also bound RII. Recombinant radixin and moesin, ezrin‐related proteins, also bound RII in blot overlay. Analysis of recombinant truncations of ezrin mapped the RII binding site to a region between amino acids 373 and 439. This region contained a 14‐amino‐acid amphipathic α‐helical putative RII binding region. A synthetic peptide containing the amphipathic helical region (ezrin409–438) blocked RII binding to ezrin, but a peptide with a leucine to proline substitution at amino acid 421 failed to inhibit RII binding. In mouse fundic mucosa, RIIimmunoreactivity redistributed from a predominantly cytosolic location in resting parietal cells, to a canalicular pattern in mucosa from animals stimulated with gastrin. These results demonstrate that ezrin is a major AKAP in gastric parietal cells and may function to tether type II A‐kinase to a region near the secretory canaliculus.
303 citations
TL;DR: In this article, a myofibrillar protein-based films were developed from a film-forming solution based on fish mince and glycerol, sorbitol, or sucrose was incorporated as plasticizer at various concentrations.
Abstract: Myofibrillar protein-based films were developed from a film-forming solution based on fish mince. Glycerol, sorbitol, or sucrose was incorporated as plasticizer at various concentrations. The increase in film solubility in water with plasticizer content reflect plasticizer solubility in water. Solubility in water of protein network is not significantly affected by plasticizer concentration whatever the plasticizer. On the other hand, plasticization of myofibrillar protein-based films induced large decreases in film strength and elasticity and increases in deformation properties and water vapor permeability. No significant difference was observed in variations of functional properties as a function of plasticizer type when plasticizers were introduced at the same molecular contents, due to the structural similarities between glycerol, sorbitol, and sucrose. Keywords: Biopackaging; myofibrillar proteins; plasticizer; functional properties
TL;DR: In this paper, the inverse relationship between recrystallization and trace-element enrichment results from km-scale variation in volume and composition of melts pervasively infiltrated in the lithosphere.
TL;DR: The combined analysis of the two genes suggests a monophyletic Cetacea +Artiodactyla clade, whereas PerissodactylA, Carnivora, and Tethytheria fall outside this clade.
Abstract: A data set of complete mitochondrial cytochrome b and 12S rDNA sequences is presented here for 17 representatives of Artiodactyla and Cetacea, together with potential outgroups (two Perissodactyla, two Carnivora, two Tethytheria, four Rodentia, and two Marsupialia). We include seven sequences not previously published from Hippopotamidae (Ancodonta) and Camelidae (Tylopoda), yielding a total of nearly 2.1 kb for both genes combined. Distance and parsimony analyses of each gene indicate that 11 clades are well supported, including the artiodactyl taxa Pecora, Ruminantia (with low 12S rRNA support), Tylopoda, Suina, and Ancodonta, as well as Cetacea, Perissodactyla, Carnivora, Tethytheria, Muridae, and Caviomorpha. Neither the cytochrome b nor the 12S rDNA genes resolve the relationships between these major clades. The combined analysis of the two genes suggests a monophyletic Cetacea +Artiodactyla clade (defined as "Cetartiodactyla"), whereas Perissodactyla, Carnivora, and Tethytheria fall outside this clade. Perissodactyla could represent the sister taxon of Cetartiodactyla, as deduced from resampling studies among outgroup lineages. Cetartiodactyla includes five major lineages: Ruminantia, Tylopoda, Suina, Ancodonta, and Cetacea, among which the phylogenetic relationships are not resolved. Thus, Suiformes do not appear to be monophyletic, justifying their split into the Suina and Ancodonta infraorders. An association between Cetacea and Hippopotamidae is supported by the cytochrome b gene but not by the 12S rRNA gene. Calculation of divergence dates suggests that the Cetartiodactyla could have diverged from other Ferungulata about 60 MYA.
TL;DR: In this article, detrital zircons extracted from three flysch samples collected in the central part of the belt were analyzed grain-by-grain using the U-Pb method.
TL;DR: Since 1993 non-occluded baculoviruses, associated with a syndrome with high mortalities, have been reported in cultured penaeid shrimp from Asia and the Indo-Pacific region, and are typically accompanied by the presence of white spots on the cuticle.
Abstract: Since 1993 non-occluded baculoviruses, associated with a syndrome with high mortalities, have been reported in cultured penaeid shrimp from Asia and the Indo-Pacific region. Infections are typically accompanied by the presence of white spots on the cuticle. Numerous names were given to the virus(es) in early reports on the disease, but the syndrome is increasingly known as White Spot Syndrome (\\YSS) and its viral agent(s) as White Spot Syndrome Baculovirus (WSSV). The \\YSS virion is a stocky rod-shaped particle w ~ t h an apical envelope extension. The nucleocdpsid is cylindr~cal with asymmetric ends, and has a superfic~al segmented appearance. The pattern of degradat~on confirms that the nucleocapsid is a cylinder formed by stacks of rlngs, which are in turn composed of 2 robvs of regularly spaced subunits. WSSV replication takes place in the nucleus and is f~rs t indicated by chromatin margination and nuclear hypertrophy. Viral morphogenesis begins by the formation of membranes d e novo in the nucleoplasm and by the elaboration of segmented, empty, long tubules. These tubules break into fragments to form naked empty nucleocapsids. After that, membranes envelop the capsids leavlng an open extremity. The nucleoproteins, which have a filamentous appearance, enter the capsid through this open end. When the core is completely formed, the envelope narrows at the open end and forms the apical tail of the mature virion.
TL;DR: The existence of Indosinian movements in Vietnam, as they have been defined by previous authors during the early century, is now accurately confirmed and this is the first insight in the occurrence of ductile strike-slip tectonics of indosinian age along NW-SE fault zones as mentioned in this paper.
TL;DR: In this article, the dependence of the conductivity both on the degree of sulfonation and on the conditions of membrane preparation are discussed, and a range of samples have been prepared with degrees of sulfonsonation up to 75% of the available sites.
TL;DR: The data demonstrate for the first time that Y. enterocolitica promotes the apoptosis of macrophages, an effect which is clearly distinct from the morphological alterations mediated by Yersinia on epithelial HeLa cells.
Abstract: Suppression of the host defense is one of the hallmarks of Yersinia enterocolitica infection. This enteric pathogen resists phagocytosis and interferes with macrophage functions from an extracellular localization (oxidative-burst generation and tumor necrosis factor alpha production). In this study, we investigated the fate of the Y. enterocolitica-infected macrophage. We found that murine J774A.1 macrophages and macrophages derived from human monocytes were killed by infection with Y. enterocolitica. Analysis of cellular morphology and DNA fragmentation revealed that macrophage cell death occurs through the induction of apoptosis. A total of 92% +/- 5% (mean +/- standard deviation) of murine J774A.1 macrophages and 74% +/- 6% of human monocyte-derived macrophages underwent apoptosis upon Yersinia infection after 4 and 20 h, respectively. The broad-spectrum caspase inhibitor Z-Val-Ala-DL-Asp-fluoromethylketone blocked completion of the Yersinia-induced apoptotic program but not the surface exposure of phosphatidylserine as an early-stage apoptotic event. Analysis of different Yersinia mutants showed that macrophage apoptosis depends on a functional Y. enterocolitica type III protein secretion system. Apoptotic cell death of macrophages was not related to the YopE-mediated cytotoxic effect of Yersinia, since disruption of actin microfilaments by a Y. enterocolitica strain expressing a restricted repertoire of yop genes, including YopE, did not result in macrophage apoptosis. Furthermore, Yersinia-induced cytotoxic alterations in epithelial HeLa cells, which are conferred by YopE, did not lead to apoptosis. Our data demonstrate for the first time that Y. enterocolitica promotes the apoptosis of macrophages, an effect which is clearly distinct from the morphological alterations mediated by Yersinia on epithelial HeLa cells.
TL;DR: In this article, a method of computing the excited state energies in Integrable Quantum Field Theories (IQFT) in finite geometry, with the spatial coordinate compactified on a circle of circumference R, was developed.
TL;DR: The increased expression, hyperphosphorylation and subcellular redistribution of ezrin upon fibroblast transformation coupled with its roles in cell shape and motility suggest a critical role for eZrin in oncogenic transformation.
TL;DR: The three-dimensional structures support evidence that the Nef-Fyn complex forms in vivo and may have a crucial role in the T cell perturbating action of Nef by altering T cell receptor signaling.
TL;DR: In this paper, the authors present quantitative measurements of the interaction between a guided optical wave and a two-dimensional photonic crystal using spontaneous emission of the material as an internal point source.
Abstract: We present quantitative measurements of the interaction between a guided optical wave and a two-dimensional photonic crystal using spontaneous emission of the material as an internal point source. This is the first analysis at near-infrared wavelengths where transmission, reflection, and inplane diffraction are quantified at the same time. Low transmission coincides with high reflection or in-plane diffraction, indicating that the light remains guided upon interaction. Also, good qualitative agreement is found with a two-dimensional simulation based on the transfer matrix method. [S0031-9007(97)04591-2]
TL;DR: In this article, the Melisey I silty layer, which marks the end of the Last Interglacial biozone in La Grande Pile pollen record, appears coeval with the polar front advance C24 registered in the core V29-191 by a sharply increased presence of ice-rafted detritus and the cold water foraminifer Neogloboquadrina pachyderma sinistral.
TL;DR: The conserved central domain of CR can be aligned across ungulates and indicates the Pecora monophyly, their close association with cetaceans, and the earlier emergence of suiformes.
Abstract: The mitochondrial control region (CR) sequence, also known as the D-loop, has been determined for six Cervidae (Artiodactyla, Ruminantia): the red and fallow deers (subfamily Cervinae), the brocket deer and two roe deers (subfamily Odocoileinae), and the Chinese water deer (Hydropotinae). These new sequences have been aligned with available cervid and bovid orthologues. Comparative analyses indicate that the 5'-peripheral domain exhibits a 75-bp length polymorphism near sequences associated with the termination of the H-strand replication. The New World Odocoileinae possess the longest cervid CR due to the presence of an additional 47-bp tandem repeat, located in the 3'-peripheral domain, downstream of the initiation site for H-strand replication (OH) and the first conserved sequence block (CSB-1). This insertion represents a duplication spanning the OH to CSB-1 region and constitutes an exclusive synapomorphy for New World Odocoileinae. Phylogenetic analyses of the complete CR support the paraphyly of antlered deers due to the nesting of the antlerless Hydropotes within Odocoileinae. Capreolus is the closest relative of Hydropotes, and the divergence of this Old World Odocoileinae clade may have occurred between 8.7 and 10.4 MYA. The conserved central domain of CR can be aligned across ungulates and indicates the Pecora monophyly, their close association with cetaceans, and the earlier emergence of suiformes.
TL;DR: In this paper, the role of intergranular and intragranular crystal boundaries has been considered and two specific approximations for boundary formation and orientation obtained using the SEM electron channelling technique are presented.
TL;DR: In this paper, the existence of a pervasive fabric in the lithospheric mantle induces an anisotropic strength that guides the propagation of continental rifts, which is supported by the anisotropies of olivine, exposed mantle rocks, and measurements of seismic and electrical anisotropy.
Abstract: The frequently observed parallelism between rifts and the pre existing orogenic fabric of continents suggests that the inherited tectonic fabric of the lithosphere influences the rupture of continents. We propose that the existence of a pervasive fabric in the lithospheric mantle induces an anisotropie strength in the lithosphere, that guides the propagation of continental rifts. Subcrustal mantle mechanical anisotropy is supported by (i) the anisotropie strength of olivine, (ii) an ubiquitous tectonic fabric in exposed mantle rocks, and (iii) measurements of seismic and electrical anisotropy. During major episodes of continent Rifting parallel to orogenic belts Ocean-opening through rifting and continent break-up is frequently related to the occurrence ofhotspots. There is, howevcr, a discrepancy between hot spots acting as pin point sources of heat and the linear extent of rifts over thou sands ofkilometres. Moreover rifts tend to parallel pre-existing orogenic fab
TL;DR: Despite an apparently similar target training level, the individualized method clearly optimized the physiological training effects in patients with chronic airway limitation and, more particularly, decreased their ventilatory requirement.
Abstract: This study tested the effect of two methods of training, one individualized at the heart rate corresponding to the gas exchange threshold (GET) and the other at the heart rate corresponding to 50% of maximal heart rate reserve, on maximal and submaximal cardiorespiratory response in 24 patients with chronic airway limitation (CAL). The patients were randomly assigned to either the individualized training group (IT; n = 12) or the standardized training group (ST; n = 12). The training programme consisted of 4 weeks of stationary bicycle exercise, 5 days.week-1. Before reconditioning began, the target level based on heart rate was not significantly different between groups (109 +/- 4 versus 110 +/- 3 beats.min-1, in IT and ST, respectively). Post-training, a significant increase in symptom-limited oxygen uptake (V'O2.sl) and maximal O2 pulse was found in IT, whereas ST exhibited no significant change. In each group, GET was statistically increased in much the same way as V'O2,sl, with a higher increase in IT (p < 0.01) than ST (p < 0.05). Nevertheless, IT exhibited a concomitant and gradual decrease in minute ventilation (V'E), carbon dioxide production (V'CO2), and venous lactate concentration ([La]), whereas ST presented no significant change in these parameters (intergroup p < 0.01). Breathing pattern was also altered after IT, at the same metabolic level and at the same ventilation level (intergroup p < 0.05). Cardiac responses were modified in the two groups. At the same metabolic level, a significantly lower cardiac frequency was found both for IT and ST (intragroup p < 0.05 after training). In contrast, the increase in O2 pulse was only significantly higher in It after training. These data show the greater efficiency of an individualized training protocol based on determination of gas exchange threshold as compared to a standardized protocol, in improving exercise performance, when applied to a patient group. Despite an apparently similar target training level, the individualized method clearly optimized the physiological training effects in patients with chronic airway limitation and, more particularly, decreased their ventilatory requirement.
TL;DR: The hypothesis that aggregation of either proteins or lipids act as a general sorting signal for exosomal processing, thereby inhibiting reentry in a recycling pathway and providing an effective means for clearing molecules from the cell surface and their eventual elimination from the cells is supported.
Abstract: Endocytosis of the Tf/TfR complex is essentially the only pathway active in maturing reticulocytes, while exosomes, formed by invagination of the endosomal membrane, provide a mechanism to eliminate seemingly obsolescent proteins, including the TfR, when their function is completed. In this study, we examined molecular trafficking in the recycling and exosome-directed pathways during endocytosis in maturing reticulocytes. To this end, the flow of two exogenously inserted fluorescent lipid analogs, N-(N-[6-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]caproyl]) sphingomyelin (C6-NBD-SM) and N-(lissamine rhodamine B sulfonyl) phosphatidyl ethanolamine (N-Rh-PE) was monitored and compared to that of the transferrin (Tf)/Tf receptor (TfR) complex. Prior to elimination via exosomes, the TfR actively recycles with a half-time of approx. 2 minutes. The recycling kinetics of C6-NBD-SM, as bulk plasma membrane marker, are identical to those of the apoTf/TfR complex, as shown by fluorescence microscopy and biochemical analysis. By contrast, although efficiently internalized along the same pathway, N-Rh-PE does not return to the cell surface. More specifically, sucrose gradient analysis and immunoisolation experiments demonstrated that N-Rh-PE accumulates in exosomes, which are eventually released into the extracellular medium. Fluorometric measurements showed that exogenously inserted N-Rh-PE is present in the reticulocyte plasma membrane as small molecular clusters. Moreover, a close correlation was observed between the fate of crosslinked proteins, including the TfR and acetylcholinesterase (AChE), and the fate of the clustered lipid N-Rh-PE. Thus antibody-induced aggregation of specific proteins like the TfR and AChE, which are normally sorted into exosomes during reticulocyte maturation, enhances their shedding by the exosomal pathway. Taken together, the results support the hypothesis that aggregation of either proteins or lipids act as a general sorting signal for exosomal processing, thereby inhibiting reentry in a recycling pathway and providing an effective means for clearing molecules from the cell surface and their eventual elimination from the cells.
TL;DR: In the last twenty years sol-gel science has undergone a spectacular development as discussed by the authors, and various stages of the solgel process have been scrutinised in considerable detail and a sound basis for future technological developments established.
Abstract: In the last twenty years sol-gel science has undergone a spectacular development. The various stages of the sol-gel process have been scrutinised in considerable detail and a sound basis for future technological developments established. In the beginning the studies centred mainly on silica and silicate glasses and were progressively extended to many ceramics and composites. A turning point was reached with the emergence of ormosils and of organic-inorganic nanocomposites. This opened the gateway to whole classes of new materials. The present studies show a definite tendency towards very specialised high-tech applications.