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1.
J. Costentin 《PSN》2010,8(4):182-186
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.  相似文献   

2.
《Comptes Rendus Palevol》2003,2(6-7):597-605
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).  相似文献   

3.
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.  相似文献   

4.
《Geobios》1988,21(6):773-785
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.  相似文献   

5.
Sandra D. Gomes 《Grana》2013,52(3):228-231
The possible impact of altitude and the related microclimatic conditions on the total production of fruiting branches, inflorescences, flowers and pollen grains of olive trees Olea europaea was analysed. A total of 90 Picual cultivar trees, the most extensive olive cultivar in the Iberian Peninsula, were studied for a three-year period (2007–2009). The study shows that production of flowers and pollen grains in a cultivar of the olive tree varies according to the microclimate. Our study also indicates that the olive trees frequently can have up to half a million flowers per tree. Moreover, the total flower production differs between years and study areas. In the Picual cultivar, the average production of pollen grains per anther is usually more than 60?000 grains. The total production of pollen per tree is around 72?000 million on average. The most favourable microclimatic conditions for reproduction in olive trees are found in years and olive growing areas with low temperature and high precipitation records during the months prior to flowering of the olive trees. We hypothesise that olive trees tend to increase their pollen production rate as altitude increases, which can be interpreted as a reproductive strategy to ensure fertilisation.  相似文献   

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8.
Zusammenfassung Der Stiel der Pedizellarien von Arbacia lixula wurde lichtund elektronenoptisch untersucht und hinsichtlich seiner Funktion analysiert. Er besteht aus einem Bündel parallel angeordneter Calcitfasern, die distal von dem trabekulär aufgebauten Stielköpfchen zusammengefaßt werden; proximal enden sie frei. Zwischen den Skelettfasern im Inneren und als deutliche Ummantelung derselben finden sich parallel, sowie auch schraubig angeordnete Kollagenfasern unterschiedlicher Dicke. In den Raum zwischen den freien Enden der Calcitfasern und dem Gelenkhöcker der Corona schiebt sich ein funktionell wesentlicher Polster feiner Fibrillen, in den die Skelettfasern bei der Bewegung verschieden tief eintauchen können. Hinsichtlich der Innervation wird die Abspaltung einer Reihe von Nerven aus dem basalen Ringnerv, ihr freier Verlauf im Stiel und ihr Übertritt in die Mm. flexores des Pedizellarienköpfchens dargestellt. Aufgrund der erhobenen Befunde wird eine funktionelle Deutung dieser für Echinodermen besonderen Kombination von Skelett und organischem Fasermaterial gegeben.
On the fine structure of the ophiocephalous pedicellariae from arbacia lixula L. (Echinodermata, Echinoidea). Functional analysis of the stalk
Summary The stalk of the pedicellariae from Arbacia lixula was investigated by the aid of light- and electron microscope and analysed regarding to its function. It consists of a bundle parallel arranged calcite rods concentrated distally in the head of the stalk, which is of trabecular construction; toward the corona they terminate freely without forming a joint surface. Inside, between the calcite rods and also as a distinct mantle around them, there are collagenous fibers of various thickness in parallel and spiral arrangement. In the lower part of the stalk the collagenous fibers pass over more and more to the peripheric mantle, which envelops the broader base of the stalk in constant thickness. Inside of the skeleton-collagen cylinder there appears now distinct accumulation of cells; their processes are to be find at the outer surface of the calcite fibers and their nuclei are arranged in a clear layer just above the joint region. In the area between the free ends of the calcite rods and the tubercle of the corona there is a cushion built up by fine fibrils. Its special function is given by the fact, that in any case of movement of the stalk, the calcite fibers are able to dip into this cushion more or less. Concerning the innervation, the separation of a series of nerves from the basal nerve ring, their free course in the stalk and their passing to the Mm. flexores of the head of pedicellaria is described. Based on all findings a functional interpretation for the special combination of skeleton and organic fibers is given.

Abkürzungen Abd M. abductor - Ax Axon - B Bügel - Bd Bandapparat - Bm Basalmembran - Cf Calcitfasern - dEf distale Endfläche - Ep Epidermis - Fl Mm. flexores - Fp Fibrillenpolster - Fpl Faserplatte - Gb Gleitbahn zwischen Stielköpfchen und Bügel - Gh Gelenkhöcker - Gk Gelenkkapsel - Kf Kollagenfibrille - Kfb Kollagenfaserbündel - LN Längsnerv - Mm Muskelmantel - ÖBd Öffnungen für den Bandapparat - Pig Pigment - pM peripherer Mantel aus Kollagenfasern - Sta Stachel - Stk Stielköpfchen - Z zelluläre Bestandteile im Inneren des Skelett-Kollagenzylinders - Za Zellausläufer - Zk Zellkerne der Bildungszone Mit Unterstützung des Fonds zur Förderung der wissenschaftlichen Forschung, Projekt-Nr.: 3425  相似文献   

9.
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.
Impact de l'échantillonnage sur la mésure des nucléotides adényliques (ATP, ADP, AMP) du microplancton
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11.
The seasonal distribution of Acanthocephalus tumescens (Acanthocephala : Echinorhynchidae) among Galaxias maculatus (Pisces : Galaxiidae) in Lake Gutiérrez was studied from March 1994 to June 1996. Acanthocephalus tumescens always occurs in the intestine, has an overdispersed frequency distribution, a similar proportion of sexes, and females are larger than males. Mean intensity and prevalence are low and increase with host length. The pattern of the infection shows seasonality, with recruitment in winter and a reproductive period during spring-summer.  相似文献   

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13.
《Geobios》1988,21(5):567-609
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.  相似文献   

14.
《Geobios》1986,19(5):641-646
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.  相似文献   

15.
《Geobios》1986,19(1):33-47
Dimorphism in the genus RichterellaAvram is confirmedon the basis of material collected in Ardeche (South east France) principally in the beds of the Fallauxi zone, from the localities of Le Pouzin and Broyon. The microconch, R. richteri (Oppel), lacks lateral lappets but a ventral horn, formed by the strongly projected forward secondary ribs, is present. The macroconch is «Lemencia praerichteriDonze & Enay. These two forms are united in the same species, R. richteri, and then in the same genus, Richterella. The microconch, which is generally better preserved than macroconch in the studied material, shows a greater variability of ribbing than previously thought, due to the poor illustrations of the lectotype of richteri (reproduced here) which showed only dichotomous ribs. The genus Richterella loses its original dimorphic sense and since its origins and its possible derivations are unknown, it became a taxon defined on morphological bases. The forms from Ardeche bear a greater resemblance to the Spanish ones than they do to the Roumanian forms. The stratigraphical and faunal contexts of Richterella in Ardeche are discussed in this work.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
Six late Rupelian populations of Nephrolepidina praemarginata (Douvillé, 1908) have been isolated from a succession of the Caltavuturo Formation (Madonie Mts, Sicily). A total of 25 embryonal parameters were obtained from oriented equatorial sections of megalospheric specimens; 8 indexes were derived from selected parameters and 9 indexes were considered for the neanic apparatus, out of which 2 are introduced here: N05 (number of annuli in a radius of 0.5 mm) and r5 (distance occupied by the first five annuli). The data show marked deviations from the expected trend of traditional biometric measures; this is interpreted as dependent on environmental factors. Previous studies on the succession evidenced an increase in basin depth; this can be inferred also from the biometric analysis of the inner characters of the allochthonous Nephrolepidina tests. Here, we explore the paleobiological potential of parameters linked to embryo size and wall thickness, and discuss how depth-dependent parameters may affect the interpretation of evolutionary trends and biostratigraphy in radial foraminifers.  相似文献   

19.
Yves Alméras 《Geobios》1980,13(3):327-409
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.  相似文献   

20.
Autoplusia egena (Guenée) is a moth distributed throughout the Western hemisphere. The larvae have already been found feeding on several different plant families, including important crops such soybeans and beans. To contribute to the knowledge of its biology in laboratory conditions, and considering the duration and the morphometry of each development stage, a laboratorial rearing was accomplished at 25 +/- 1 degrees C, 70 +/- 10% RH and 14h photophase. The larvae were fed with black bean leaves and the adults were fed with a honey solution at 10%. The results, expressed by the mean (+/- SE), for the periods of each stage were: egg 3.0 +/- 0.00 d; larva 15.7 +/- 1.25 d; pre-pupa 1.9 +/- 0.05 d; pupa 8.8 +/- 0.09 d and adult: longevity 12.1 +/- 0.95 d, pre-oviposition 5.4 +/- 0.50 d, oviposition 6.3 +/- 1.10 d and post-oviposition 1.4 +/- 0.87 d. The larvae went through five instars, for which the mean width of the cephalic capsules were 0.302 +/- 0.001 mm; 0.500 +/- 0.003 mm; 0.854 +/- 0.008 mm; 1.424 +/- 0.011 mm and 2.744 +/- 0.053 mm. The average length, width, and weight of the pupae were 16.965 +/- 0.003 mm, 4.674 +/- 0.040 mm and 0.217 +/- 0.003 g, respectively.  相似文献   

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