Influence des conditions expérimentales sur le taux respiratoire des copépodes planctoniques

Measurements of oxygen consumption were carried out on two planktonic copepods, Temora stylifera Dana and Centropages typicus Kröyer under two experimental conditions, namely, degree of confinement and length of time spent in the laboratory. The effect of population density was studied for concentrations between 0.1 animal/ml to 2 animals/ml; the highest rate of respiration was observed in both species for a concentration of 0.5 animal/ml. Concentrations higher (1 or 2 animals/ml) and lower one (0.2 to 0.4 animal/ml) caused a decrease in the respiratory rate. Single animals have respiratory rates similar to those found with a concentration of 0.5 animal/ml. The observed effect of population densities did not depend on the absolute experimental volumes.     

Imagerie des tumeurs endocrines digestives : le point de vue du radiologue

Endocrine tumor (ET) can produce and secrete hormones to a variable degree. These neoplasms present a diagnostic challenge, both clinically and radiologically. ET is classified as either syndromic or nonsyndromic on the basis of their clinical manifestations, as differentiated and undifferentiated according to their histological patterns and as pancreatic or extra-pancreatic. Multi-detector row computed tomography (CT) plays an important role in the diagnosis and staging of these lesions. In general, syndromic ET are less than 3 cm in size. They are typically hyperenhancing on CT scans during arterial phase. Nonsyndromic ET tend to be larger than syndromic one and are more likely heterogeneous. Detection of pancreatic localisation and staging of hepatic metastasis could benefit to magnetic resonance imaging (MRI). Endoscopic ultrasound and somatostatin receptor scintigraphy are the two main tools for diagnosis and staging ET. This work presents the role of imaging in the staging and the treatment of these patients.     

Corrélations de croissance entre le mycélium et les rhizomorphes chez le Sphaerostilbe repens

Correlation of Growth between Mycelium and Rhizomorphs in Sphaerostilbe repens In Sphaerostilbe repens Berkeley and Broome, cultured on a solid medium in Petri dishes, growth of mycelium and chizomorphs depends on the thickness of the culture medium underlying the thallus. On shallow layers of agar medium, aggregated units were fewer and rhizomorph growth reduced. Vegetative mycelium which starts growth earlier than rhizomorphs contributed to inhibit the development of these latter. On deep layers of substrate, rhizomorphs were numerous, elongated rapidly, and eventually inhibited undifferentiated mycelium. – There was no evidence for the involvement of any inhibitor substance diffusing into culture medium or located in the thallus. Development of aerial mycelium and rhizomorphs, could, on the contrary, be interpreted as nutritional competition between these two parts of the colony.     

L'évolution parallèle des Juraphyllitidae euroboréaux et téthysiens au Pliensbachien: le rôle des contraintes internes et externes

Au Pliensbachien, un trend morphologique se developpe chez les Tragophyllocerassimpliquant un mécanisme hétérochronique (paedomorphose par néoténie) pour I'acquisition d'une morphologie suboxycône. Ce changement morphologique majeurest concomitant avecl'ingression de ces formes dans les mers de plateforme euroboréale ob la compétition inter-taxons est forte. Cette option morphofonctionnelle et évolutive, canalisée essentiellement par des contraintes externes étant amorcée, le genre va I'exploiter dans la mesure de ses possibilités (potentialités intrinsèques) en perfectionnant son oxycônie. Au contraire dans les mers téthysiennes, les Juraphyllites ne montrent pas d'évolution pour la morphologie de la coquille; celle-ci reste subplatycône durant tout le Lias moyen et il n'y a pas de changements environnementaux majeurs (milieux tamponnés). En outre la prolifération d'ornementations plus grossières, aussi bien chez les Juraphyllites que chez les Tragopbylloceras, correspond probablement à une meilleure exploitation des biomes d'Europe du NW et de la Téthys à une période bien précise qui est le Carixien moyen. Ce développement d'ornementation similaire chez des taxons partageant un héritage évolutif commun mais séparés paléogéographiquement, évoque le rôle prépondérant des contraintes internes. Ainsi l'évolution des Juraphyllites des Tragophyllocerasau Lias moyen paraît donc ètre un exemple de parallèlisme au sens strict du terme.□Évolution, hétérochronies, Juraphyllitidae, Lias, ontogenèse, Paléogéographie. A morphological trend in the Pliensbachian Tragophyllocerns involves a heterochronic process (paedomorphosis by neoteny) to acquire a suboxycone morphology. This major morphological change is concomitant with the ‘ingression’ of Tragophylloceras in the Euroboreal platform seas, where competition between taxa was strong. This functional-morphological and evolutionary option is mainly canalized by extrinsic constraints. Exploring these possibilities, Tragophylloceras then exploits and improves the oxycone option. By contrast, in the Tethyan seas, Juraphyllites shows no change in shell coiling; it stays subplatycone during all the Pliensbachian. There is no major environmental change. Moreover, the proliferation of coarser ornamentation in Juraphyllitesand Tragophylloceras probably corresponds to a better exploitation of the Euroboreal and Tethyan marine habitats during the Middle Carixian. The development of similar ornamentation in palaeogeographically separate taxa with a common evolutionary origin is mainly canalized by intrinsic constraints. The evolution of Juraphyllites and Tragophylloceras appears to be a good example of parallelism sensu stricto. □ Evolution, heterochrony, Juraphyllitidae, Lios, ontogeny, palaeogeography.     

Classification et aspects anatomopathologiques des tumeurs endocrines digestives

Gastrointestinal and pancreatic endocrine tumors GIPET are rare and represent only 2 % of malignant tumors. Beyond their common features, endocrine tumors are characterized by a marked diversity, which results from the large functional, structural and embryological heterogeneity of normal endocrine cells. Despite the rational basis for predicting prognosis provided by the WHO classification, there is no reliable means of predicting the clinical course of patients with gastrointestinal and pancreatic endocrine tumors. The current criteria used for the definition of the tumor grade remain unsatisfactory. According to the WHO classification system, pathologists vary significantly in their reporting of endocrine tumors. Recently, the European Neuroendocrine Tumour Society (ENETS) has proposed a TNM (tumor–node–metastasis) classification for gastrointestinal and pancreatic endocrine tumors. The use of this classification is considered simple and valuable. It is hoped that the combination of WHO classification, with anatomical staging systems TNM, and possibly incorporating molecular features of gastrointestinal and pancreatic endocrine tumors will provide clinicians with effective means of classification and prognostication of patients with these tumors.     

Stratégie de débitage et mode de façonnage des industries du Paléolithique inférieur en Chine et en Europe entre 1 Ma et 400 000 ans: Ressemblances et différences de la culture de l’homme de Yunxian et Acheuléen européen

These stone tools from Yunxian with other Lower Paleolithic sites in South China, for example, the site Lantian (Shanxi, China) and the site Bose (Guangxi, China), indicates that there are many common characteristics among these industries. There are choppers, chopping-tools, picks, hand-axes, cleavers and scrapers. Long ago we thought that there are not hand-axes in China. In fact, there are lots of hand-axes in China and these hand-axes existed more earlier than those in Europe. The hand-axe appeared in China before 800,000 years old and it barely arrived in Europe before 600,000 years old. The quaternary deposits of the site of Yunxian Hominid (Hubei, China) are at least dated to 800,000 years old. A large quantity of lower Paleolithic material was discovered. The types of the tools are choppers, picks, scrapers, hand-axes and cleavers. The pebbles tools make up the majority of the implements. Small flake tools are relatively rare. The lithic industries comparison of the two regions has help us to know the cultural evolution in China and Europe.     

La frontière entre le Châtelperronien et l’Uluzzien : analyse comparative des typologies lithiques sur la base des dernières découvertes

The end of the Middle Paleolithic sees the appearance of “transitional” industries, which emerge at the same moment as anatomical modern humans enter Europe. All these transitional industries come from a Mousterian background and are closely connected to late Neanderthals. Among these industries we find two traditions characterized by backed blade pieces in Western Europe: the Châtelperronian and the Uluzzian. Two big conditions have been defined to allow a comparison between these industries: a chronological continuity and a geographic link. The recent data allows a new comparison.     

Relations entre production et localisation de mycosporine et morphogenèses reproductrices chez le Pyrénomycète Gnomonia leptostyla

Relations between production and localisation of mycosporin and reproductive morphogenesis in the Pyrenomycete Gnomonia leptostyla.
The production of mycosporin (P310) has been analysed in Gnomonia leptostyla (FT.) Ces. et de Not. during mycelial growth and reproductive morphogenesis (macroconidiogenesis, microconidiogenesis and differentiation of perithecia). Conidiogenesis is induced in illuminated cultures while darkness promotes perithecial development. At 20°C, the cultures produce either macroconidia or perithecia with abortive sporophyte. Microconidia differentiation and perithecia maturation require low temperature (10°C). Mycosporin is, at all times, present in the thallus. However, the concentration of mycosporin in highest in the conidiogenous thallus, intermediate in the perithecial thallus. and lowest in the vegetative mycelium. In the conidiogenous thallus, macroconidia and microconidia are both sites of mycosporin accumulation. On the contrary, in the perithecial thallus, mycosporin levels are not higher in perithecia than in mycelia, even during their maturation period. The quantitative variations of mycosporin during the thallus development and its accumulation inside conidia suggest translocation from sites of synthesis towards reproductive cells.     

Rôle des polyphénols dans la croissance. Définition ďun modèle expérimental chez Lycopersicum esculentum

Using young plants of Lycopersicum esculentum Mill., we attempt to define a system for a new evaluation of the physiological role of polyphenols, particularly of their regulating properties on growth and development, Exogenously supplied qoinic acid causes an important increase of the phenolic content and a reduced growth of the plants. The decrease in size is proportional to the stimulation of the phenolic pool and is equally obtained using other precursors of aromatic compounds like phenylalanine and cinnamic acid. Non-precursors of polyphenols structurally related to quinic acid are ineffective. It appears from these data that polyphenol levels and growth could be related in tomato plant and that this material would be convenient for studies on interactions between growth and polyphenols.     

Lithostratigraphie et biostratigraphie des formations paléocènes et éocènes entre Bayonne et Pau (SW France)

The lithostratigraphy and biostratigraphy of the Paleocene and Eocene formations have been reconsidered on the basis of 18 dated boreholes that intersect the Basque Country, Peyrehorade, Sainte-Suzanne and Sauvelade allochthonous tectonic units, as well as the autochthonous units of the Pey-Saint-Lon anticline, the Arzacq Basin and the North Pyrenean Trough. Correlation of the formations identified in the boreholes and at outcrop has made it possible to outline the sedimentary evolution of this region during the Early Paleogene and to date the various stages of Pyrenean compression on the basis of sedimentary gaps and syntectonic detrital input. The Lasseube Formation is present over the entire study area. Sedimentation becomes differentiated during the Late Selandian-Early Ypresian period. In the North Pyrenean Trough and in the Peyrehorade, Sainte-Suzanne and Sauvelade units, the detrital-clayey Pont-Labau Formation is well developed and all its members are represented (Guillempau, Latapy, Néez, Libaros and Artigueloutan; zones upper P 3b-P 6b; upper NP 5-NP 11). A sedimentary gap showing erosion, and involving zones upper P 3b-upper P 4a and upper NP 5-NP 7, characterises the Basque units, the Pey-Saint-Lon anticline and the western part of the Arzacq Basin. Sedimentation recommences in zone P 8 with middle-bathyal deposits of the Cassoua Member and then continues with the Artigueloutan Member (transition facies towards the Louts Formation) or limestone resembling that of the Meilhan Formation. The Gan Formation shows an east-west polarity. In the east, between the Sainte-Suzanne Unit and the North Pyrenean Trough, the formation is argillaceous with a dominant neritic character, apart from a circalittoral to epibathyal passage in its lower part (zone P 7) containing numerous planktonic foraminifera. The formation is of a detrital and carbonate nature in the west (Sainte-Marie-de-Gosse 1). The bathyal Donzacq Formation appears to transgress a previously deformed surface. Two domains existed during the Lutetian: a continental to neritic domain in the south and a bathyal domain in the north (the Saint-Geours-d'Auribat and Miretrain formations) separated by a variably thick transition zone that is affected by thrust fronts. Two new formations - the Orthez and Sorde-l'Abbaye formations - are proposed, and the Marly limestone formation of Saint-Barthélémy (Douvillé, 1905) is redefined. The Orthez Formation (Sauvelade Unit) is composed of marl and continental conglomerate with neritic carbonate interbedding and belongs to the sub-zones NP 15a and b. The Sorde-l'Abbaye Formation (Peyrehorade Unit and the Basque units p. p.) is composed of neritic carbonate sediments (Lutetian-Priabonian). The Saint-Barthélémy Formation is made up of syntectonic conglomerate, turbiditic limestone and pelagic marl in the central part of the Basque units (NP 15a-NP 16). The Bartonian and Priabonian stages are characterised by carbonate sediments in the Arzacq Basin (Siest Formation). Its base is diachronous: Upper Lutetian (zone SB 16) in the east and Late Bartonian grading to Priabonian in the west (zones SB 17/18 and SB 19). The sediments are argillaceous (Côte des Basques Formation) along the Atlantic coast, in the central part of the Basque units and in the Bayonne-Cauneille syncline. Major thickness variations reflect tectonic phases at the top of the Lasseube Formation in the north (erosion pre NP 8), the Néez Member (NP 7/NP 8 boundary), the Artigueloutan Member (NP 11/NP 12 boundary), and the Gan Formation (P 8/P 9 boundary). The syntectonic conglomerate and breccia indicate the development of thrust fronts in the Libaros Member (NP 8), at the base of the Pillardou and Artigueloutan members (NP 9b, c-NP 10), in the Saint-Geours-d'Auribat Formation (NP 14b) and in the Orthez and Saint-Barthélémy formations (between zones NP 15a and NP 16).