Principaux effets neurotropes et psychotropes des méthylxanthines (caféine, théophylline, théobromine, paraxanthine)

Caffeine, the main alkaloid in coffee, corresponds to the 1-3-7 trimethylxanthine. Its concentration is lower in tea and chocolate, where it is associated with theophylline, 1-3 dimethylxanthine, in tea and with theobromine, 3-7 dimethylxanthine, in chocolate. Paraxanthine, 1-7dimethylxanthine, for its part, is produced by the hepatic metabolism of caffeine operated by a cytochrome of 1A2 type. The effects of these methylxanthines on awaking, anxiety, neuroprotection in Alzheimer’s and Parkinson’s diseases, mood, schizophrenia and nociception are briefly considered. This review is concluded by indicating that these effects of methylxanthines may be modified by various associated substances, such as polyphenols displaying antioxydant properties.     

Fluctuations morphologiques et hétérochronies chez Toxaster (échinides,Crétacé inférieur)

Morphological fluctuations and heterochronies of Toxaster (echinoid, Lower Cretaceous). Several steps of the diversification of the spatangoid Toxaster are described with an analysis of six species distributed over the north-west Tethyan margin, and ranging from the Lower Valanginian to the Barremian. Morphological variation was investigated with the analysis of two parameters (angles), which allowed recognition of three modules on the test. Comparison of ontogenetic trajectories of two reference species (T. granosus kiliani and T. retusus) suggests a peramorphic heterochronic pattern. However, no peramorphocline can be attested when comparisons are extended to adults of the six species. Evolution among these species is partially driven by allometric changes in one module, indicating an important influence of size. On the temporal and spatial scale of the study, the evolution of Toxaster appears globally quite conservative. To cite this article: É. François et al., C. R. Palevol 2 (2003).     

Les Pachyerymnoceras (Pachyceratidés,Périsphinctacés,Ammonites) du Callovien moyen et supérieur de la région de Saida (Algérie occidentale). Origine phylétique et biogéographie des Pachyceratidés

The genus Pachyerymnoceras, with four new species,is described for the first time in Western Algeria. The genus first appears in the Middle Callovia (Coronatum Zone) as in Saudi Arabia. It is represented in the Saida region by uncommon P. praecox nov. sp. followed during the Upper Callovian (Athleta Zone) by specimens belonging to P. flamandi sp. nov., P. kmerense nov. sp. and P. saidense nov. sp. Every species is represented by a dimorphic pair.Pachyceratidae are put into Perisphinctaceae. If Pachyerymnoceras arises from Erymnoceras, a genus suddenly appearing during the Middle Callovian on northern and southern Tethyan borders, the origin of Erymnoceras is still unknown. Three phylogenetic hypothesis are considered here. Erymnoceras may have evolved during Lower Callovian: 1) from serpenticonic Tethyan Pseudoperisphinctinae like Choffatia (Subgrossouvria); 2) from Tulitids via ellipticoncic Bullatimorphites (Kheraiceras); 3) through a double lineage arisen in Subboreal and Tethyan platyconic Proplanulitids.Pachyceratids have a wide paleobiogeographic distribution in NW Europe and on the Tethyan margins. The genus Pachyerymnoceras evolves in Ethiopian Province of the Tethyan Realm. Some species migrate into Indo-Malagasian Province and others, through the south Tethyan border came to Europe were they are found restricted to Upper Callovian (Athleta and Lamberti Zones). Therefore this migration has a duration of two or even three zones.     

Impact de l'échantillonnage sur la mésure des nucléotides adényliques (ATP,ADP, AMP) du microplancton

The influence of sampling and sample treatment upon adenylic nucleotide (ATP, ADP, AMP) content of microplankton is studied. Changes in light conditions during nigh-sampling and extracting do not induce significant variations, in the adenylic nucleotide content of microplankton or in energy charge values.The contribution of zooplankton (size up to 200 µm) to microplankton adenosine values can be neglected for inshore surface waters and traditional sample volumes (about one liter). This result can been explained by the low density of zooplankton in such a small sample volume and by differences in efficiency of the extracting method used.

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Impact de l'échantillonnage sur la mésure des nucléotides adényliques (ATP, ADP, AMP) du microplancton

     

La genre Scinaia (Rhodophycées,Nemalionales) de la Méditerranée occidentale

Abstract

The genus Scinaia (Rhodopbyta. Nemalionales) of the western Mediterranean sea. Only 3 species of Scinaia are to be found in Western Mediterranean sea. Scinaia complanala, S. furcellata and S. turgida. Scinaia sanctaluciana Funk is considered as a juvenile thallus of Scinaia complanala. Scinaia turgida is recorded for the first time in the Tyrrhenian sea since MAZZA (1902, 1903). A new anatomical character for the distinction of the Scinaia complanala and Scinaia turgida is also given.     

Le genre Palaeoreas (Mammalia,Artiodactyla, Bovidae), systématique et extension géographique

The discovery of bovids referred to the genusPalaeoreas from localities near Thessaloniki allows to define more accurately the characteristics of this genus which appears to be restricted to the end of the Miocene with limited geographical extension (southern part of eastern Europe) and which is represented by two species:P. lindermayeri (Wagner) andP. zouavei n. sp.     

Sélaciens nouveaux (Chondrichthyes,Neoselachii) du Paléocène supérieur de la région d’Ouarzazate,Maroc

Three new selachian species belonging to new genera from the Thanetian of Ouarzazate Basin are described: Tingaleus dakkai n. gen. et nov. sp., Microbatis sabatieri n. gen. et n. sp. and Garabatis atlasi n. gen. et n. sp. These new taxa as well as the associated selachian species confirm the original feature of this fauna in comparison with contemporaneous faunas occurring in the phosphate-bearing horizons of central Morocco.     

Une faune inédite de coraux scléractiniaires dans le gisement chattien d'Escornebéou (Landes,SW France) ; stratigraphie,systématique et paléoécologie

The Escornebéou locality (Landes, SW Aquitaine Basin) is a reference site for the marine Chattian of atlantic tropical type. The abundant microorganisms allowed these outcrops to be allocated to the classic biozonations, after numerous historical controversies about their age. A fauna of Scleractinian corals has been discovered there for the first time, mainly from the ‘Le Bois’ site. About 25 taxa are listed and their systematics is analysed. They split up into 18 genera and subgenera, with stratigraphically a cachet intermediate between the Oligocene and Miocene faunas. There are as many solitary species as colonial ones (mainly hermatypics). The presence of numerous reefal genera confirms the tropical (to subtropical) paleoclimate, as well as the data from the other present organisms. Concerning the coarse zoogene calcareous deposits from ‘Le Bois’ (where the coral colonies are massive), the environment was shallow, fairly turbulent and under the effect of currents and waves. A subreefal facies locally developed (with mixed hermatypic and ahermatypic corals), belonging to the paleogeographic domain of shoal-type or barrier-type bioclastic limestones, as recognized elsewhere. At Escornebéou, the outcropping sequence is mainly marly to fine-grained sandy-marly (including such coarse calcareous intercalations), as at Lespeyrères, where few corals have also been found. These calm environments, of sheltered marine mud flat or seaweed type, were not very favourable to coral growth.     

Nouvelles données paléontologiques,paléoécologiques et sédimentologiques sur le Berriasien de la région de Lamoricière (ouled Mimoun et E1 Rhoraf,Monts de Tlemcen,Algérie)

In the Western Algerian area, the Ouled Mimoun and El Rhoraf sections are particularly appropriate for the study concerning the berriasian formations.From tha lithostratigraphical point of view, the upper section of the carbonated platform corresponds to the lower Berriasian and a part of the middle Berriasian. The «Argiles de Lamoricière which dominate it belong to the middle and upper Berriasian. The subjacent detritic formation known as «Grès de Berthelot probably begins with the lower Valanginian. The stratigraphical results are based on an abundant fauna (ammonites, ostracods) collected in situ, the main species of which have been the subject of a paleontological review and abondantly illustrated.The studied series offer a good example of the evolution of sedimentary conditions which accompany the temporary opening of a carbonated platform towards the open sea.The variations in fauna composition are closely related to changes in environment. In particular, the presence of ammonites in the Boissieri zone can be connected to the highest point of marine advance, although the depth remained relatively shallow (an upper infratidal zone being likely). It is to note that during this period the low level of sedimentary activity favored the settling of some remarkable epilithic fauna.Above the «Argiles de Lamoricière, the massive detritic sedimentation (grès de Berthelot) could indicate an important paleogeographical change in the interior. In the area studied, the ostracods encountered in the basal section of the last formation still mean a shallow marine environment.     

Les cyprinodontiformes (Poissons téléostéens) oligocènes de Ronzon,Le Puy-en-Velay (Haute-Loire): Anatomie et signification paléoécologique

The revision of the fossil fishes from the Lower Oligocene of Ronzon, Le Puy-en-Velay (Haute-Loire, France), leads one to give a more precise account of their main anatomical and meristic features. According to the rules of zoological nomenclature, the unique fish species known from this locality must be named Prolebias aymardi (Sauvage). Some palaeoecological characters of these fishes are specified.     

Acanthochaetetidae (Hadromerida,Demospongiae) fromthe Coniacian of Vera de Bidasoa (basque pyrénées,Northern Spain)

Acanthochaetetes specimens from the Coniacian brecciated limestones near Vera de Bidasoa (Northern Spain) are described. It is the first report of acanthochaetetids from Coniacian strata. The specimens are very small and probably lived in fissures and crevices in fore-reef breccias and deep water mud mounds. The family Acanthochaetetidae Fischer is placed in the order Hadromerida (Tetractinomorpha, Demospongiae). The order Tabulospongida Hartman & Goreau was abandoned.     

Révision du genre Pycnomorphus Thomson, 1864. Systématique et phylogénie (Coleoptera : Lamiinae,Acanthoderini)

Le genre Pycnomorphus Thomson est révisé et quatre espèces nouvelles sont décrites: Pycnomorphus guyanensis n. sp., P. pradosiae n. sp.et P. sarryi n. sp. de Guyane, et P. batesi n. sp. du Nicaragua. Un genre nouveau Pycnomorphidiellus n. gen. est créé pour une nouvelle espèce de Guyane, P. polyphagus n. sp. Une analyse cladistique et une clef d’identification des espèces complètent ce travail.     

Révision systématiquedu genre Sphenorhynchia Buckman, 1918 (Brachiopoda,rhynchonellidae): Implications taxonomiques, évolution,biostratigraphie

A lot of numerous rhynchonellid shells referedto the main species of genus SphenorhynchiaBuckman have been sampled in stratigraphically well-defined beds of Dogger period in the Mâconnais and in the Jura (France). Here, morphologic and anatomic characters and variability of S. plicatella, S. matisconensis, S. bugeysiaca, S. ferryi and S. dominula are studied.The main interest of this revision is to establish a complete diagnosis of the genus, not studied since its creation in 1918, with very limited knowledge of the internal structures. The settlement of this diagnosis is based on the type-species, S. plicatella, sometimes a little «unconventional form (beak, outline of the young shells, orientation of dental lamellae, delthyrial cavity), and also on the other species' characters. So, I expect that a later diagnosis will be avoided.Other advantages are observations on the taxonomic place of Sphenorhynchia in the RhynchonellidaeGray (in the TetrarhynchiinaeAger rather than in the CyclothyridinaeMakridin), on its evolution in the course of the Dogger period and the establishment of the biostratigraphy of its main species.     

Loreleiella nov. gen., nouvel éodévonariidé(Chonetacea,Brachiopoda) du Dévonien

The detailed morphological analysis of the dorsal interior of Chonetes arcuatus Hall, 1857, typespecies of the genus Eodevonaria (North American Lower Devonian), compared with those of the European species classically assigned to this genus, allows the erection of a new genus for the European eodevonariids. The phylogenetic relations of Loreleiella nov. gen. and its paleobiogeographic implication are discussed.     

Nouvelles données sur l’évolution paléoclimatique de l’époque magdalénienne,d’après l’étude lithostratigraphique du Roc-aux-Sorciers (Angles-sur-l’Anglin,Vienne, France)

Situated a few kilometres from Angles-sur-Anglin (Vienne, France), the Roc-aux-Sorciers cave has yielded in 1927 and 1950 industry of the Middle and Upper Magdalenian periods. Our analyses of the sedimentary filling, dated from isotope stage 2, demonstrate the existence of two climatic sequences in the six ensembles defined during the excavations. A first sequence, at the base of the cave filling, corresponds to the occupation levels of the Middle Magdalenian and of the early Upper Magdalenian. At that time, the climate was globally cold and particularly humid, a conclusion that does not support Bastin's 1975 hypothesis on the oscillation of Angles-sur-Anglin, which postulates a mild and humid climate. In fact, the climate evolved progressively towards a slight warming from the base to the top of the stratigraphy. During the second sequence, corresponding to the occupation period of the Upper Magdalenian, the relatively stable climate was slightly warmer and quite humid. Stratigraphical and sedimentological data thus provide new information on the conditions under which the filling was deposited and on the palaeoclimatology of the Poitou-Charentes region during Magdalenian occupation.