Apports de la palynologie a la connaissance du Pliocène du Roussillon (sud de la France)

The present study illustrates clearly how pollen analysis may be applied to stratigraphy from a botanical point of view. Within a chronologically reliable frame (Middle Pliocene for the marine deposits on the basis of Foraminifera record; two subzones for continental deposits on the basis of Mammals record: Hautimagne for Terrats fauna, Sète for Serrat-d'en-Vacquer fauna), palynology provides a good stratigraphical boundary: the extinction of the Taxodiaceae. In a remblayage area, it is established that a continental level is not necessarily younger than a marine one unless they are superposed. Many profiles are replaced according to the «progradation of the pliocene gulf of Roussillon. The boundary between marine and continental deposits cuts through the chronological line of the Taxodiaceae extinction. The flora investigated (93 taxa) is the first known for the Pliocene of this area. The extinction of the Taxodiaceae in southern France has a climatic cause: the setting in of a mediterranean rhythm (dry summers). This extinction is much older than the one which took place in Italy (Tiberian boundary) and in the Netherlands (Reuverian-Pretiglian boundary).     

Essais de thermorésistance de l'organisme responsable de la maladie laiteuse de la Larve du Hanneton (Melolontha melolontha)

Summary The organism responsible for the milky disease of the cockchafer (Melolontha melolontha) when diluted in distilled water and heated for 1 hour at 84°C retains its infectivity. However this temperature diminishes the vitality of the organism, in order to eliminate the saphrophytic organisms of the haemolymphe, it is preferable to heat to use a temperature of 75°C.

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avec la collaboration technique deH. Chaumont     

Le zooplancton de la baie de Sh?diac (Nouveau-Brunswick)

Analyses of boreal zooplankton of Shediac Bay demonstrate theabundance of copepods (81%) and meroplankters (18%). Whetherexclusively pelagic or not, 67 species are mentioned for thefirst time in this Northumberland Strait area, out of 76 recordedwithin 23 higher taxa. The fluctuations were observed from Mayto November and pointed out the dominance of such copepods asAcartia tonsa, A. clausi, Oithona similis and Centropages hamatusin relation with temperature, salinity and food distributions. ¹Adresse actuelle: Station marine de Tul?ar, B.P. 141, Universit?de Madagascar, (R?p. Malgache)     

Influence de la présence de la fourmi Wasmannia auropunctata (Roger 1863) (Hymenoptera : Formicidae) sur les autres espèces de fourmis dans la réserve de la Lopé (centre du Gabon)

Résumé

Wasmannia auropunctata (Roger 1863) est une fourmi originaire d’Amérique du Sud. Elle a été introduite au Gabon vers 1920 par des agronomes qui l’ont utilisée comme agent de lutte biologique contre certains insectes parasites du cacaoyer. Aujourd’hui, cette fourmi se retrouve en zone forestière même hors des anciennes plantations de cacaoyers. Depuis 1984, sa présence a été signalée dans le parc national de la Lopé qui fait partie des réserves protégées du Gabon. Des études antérieures réalisées en Nouvelle-Calédonie ont montré que la présence de W. auropunctata a d’énormes conséquences sur la biodiversité car elle a fait disparaître l’ensemble des fourmis de cette région. Quel peut donc être l’impact de sa présence au Gabon dans la zone de la Lopé? Ces études préliminaires de l’impact de W. auropunctata sur la biodiversité de la Lopé ont consisté à évaluer la dispersion de cette espèce et la densité relative des autres espèces de fourmis en présence sur le site. Les résultats montrent que W. auropunctata se répartit selon un gradient décroissant du point d’introduction vers l’intérieur de la forêt jusqu’à une distance de 120 m. Il n’y a pas de W. auropunctata au-delà de cette distance. Du point d’introduction jusqu’à 80 m de distance, la densité relative des autres espèces de fourmis varie de 0 à 10 %. Lorsqu’il y a forte densité de W. auropunctata, les autres espèces de fourmis sont absentes.     

Orthida (brachiopoda) de la formation de Postolonnec (Ordovicien) Finistère,France

Three species of Orthida are described from the «Schistes de Postolonnec Formation. The distribution of Crozonorthis musculosa n. g., n. sp. allows to improve the correlations between the Iberic Peninsula and the Armorican massif and supply new arguments for a Llandeilian age to a part of the «Schistes de Postolonnec Formation.     

Structure de la strate arborescente dans un site de la forêt de montagne du Rwanda (Arfique centrale)

Résumé Dans un site de la forêt de montagne du Rwanda, diverses méthodes d'étude de la structure de la strate arborescente sont présentées. Grâce à diverses méthodes d'ordination et de classification, il est possible de représenter la distribution de la surface terrière de plusieurs espèces d'arbre le long d'un gradient d'humidité. L'analyse des coefficients de corrélation entre individus adultes et jeunes fait apparaître des différences entre l'écologie des arbres jeunes et adultes; à cause de la variance élevée des données, une standardisation est nécessaire. Le diamètre de l'arbre de surface terrière moyenne est une valeur de synthèse très intéressante sur le plan écologique. Les caractéristiques dendrométriques et écologiques de 4 groupements végétaux sont présentées; les courbes de fréquences de circonférences de trones sont un complément intéressant dans la compréhension de l'écologie des espèces.

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Summary In a site of the Rwanda upland forest, different methods of study of the tree layer structure are presented. By using diverse ordination and classification methods, it is possible to represent the distribution of the basal area of several species along a moisture gradient. The analysis of the correlation coefficients between adult and young individuals of a same species exhibits differences in the ecology of young and adult trees; because of the high data variance, a standardization is necessary. The diameter of the tree of mean basal area is a very interesting synthesis value from an ecological point of view. The ecological and dendrometric characteristics of four groupings are presented; the frequency curves of trunk girth are an interesting complement to the understanding of the species ecology.

Toutes les données présentées ont été rassemblées pendant notre séjour à l'Institut national de la Recherche scientifique du Rwanda. Les ajustements à la fonction béta ont été réalisés sur l'ordinateur IBM 1130 de la Faculté des Sciences agronomiques de l'Etat à Gembloux; nous remercions vivement le Dr. J. Rondeux pour sa collaboration dans la réalisation du programme et des calculs.     

Ultrastructure de la glande de la spermathèque chez Phosphuga atrata L. (Coleoptera Silphidae)

Résumé Chez les Silphes et en particulier chez Phosphuga atrata, la glande de la spermathèque présente une structure particulière liée à la présence d'une intima cuticulaire tapissant la lumière de la glande. Elle comporte trois types cellulaires: les cellules sécrétrices, les cellules de l'épithélium sous-cuticulaire et les cellules-manchons. Les cellules sécrétrices de grande taille contiennent une invagination de la membrane cytoplasmique formant une «vacuole» extracellulaire bordée de microvillosités. Dans cette vacuole plonge l'extrémité, différenciée en ampoule poreuse, d'un canalicule de nature cuticulaire, qui véhicule la sécrétion jusqu'à la lumière de la glande. Le canalicule est élaboré par une cellule-manchon qui l'accompagne sur toute sa longueur sauf à son extrémité intravacuolaire.Ce type de glande, qui se retrouve chez de nombreux Insectes, y assurant des fonctions diverses (sécrétion odorifique, sécrétion de défense, sécrétion spermale, etc.), est susceptible de nombreuses variations.

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Ultrastructure of the spermathecal accessory gland in Phosphuga atrata L. (coleoptera: silphidae)

Summary The spermathecal accessory gland in the female of Phosphuga atrata (Silphidae), exhibits a special structure which is due to the presence of a cuticular intima lining the lumen. The wall of the gland shows three cellular types: the secretory cells, the epithelial cells and the ductule carrying cells. Each large secretory cell contains a cavity formed by an invagination of the cytoplasmic membrane and lined by many microvilli. The secretory cell is connected with a cuticular ductule ending in the cavity of the glandular cell, in a porous organelle. This ductule, which carries the secretory material to the lumen, is surrounded by the ductule carrying cell.This type of integumentary gland is very common in insects, where it assumes various functions (attraction, defense, conservation of sperm, etc.) and its morphology varies considerably.

     

Analisis de la craneometria diferencial entre la vicuña (Vicugna vicugna) y la alpaca (Lama guanicoë pacos)

Using a total of 43 craneological data obtained from any of 73 vicugna and 25 alpaca skulls, three problems were analyzed:

• Identification of skulls

• Taxonomic situation of the vicugna

• Origin of the alpaca.

For rapid identification of New World cameloid skulls it is recommended to use the condilobasal length, the length to heigth ratio and the presence of the Fissura nasolacrimalis.

Some characteristics of the skulls considered essential for the evaluation of domestication processes exclude the vicugna from the alpaca's ancestors.     

Les ultrastructures nucléaires de la Noctiluque (Dinoflagellé libre) au cours de la sporogenèse

The trophozoït of Noctiluca miliaris has a large nucleus (30 ) with several nucleoli of considerable size that contain DNA fibrillae lying in the interspaces. — Before and during the first sporogenetic divisions, the nucleoli disintegrate, releasing towards the cytoplasma numerous groups of ribonucleic granules passing through the nuclear ampullae. At the end of the sporulation, there are no nucleoli visible in the nuclei and no ampullae. — The nucleoplasm diminishes, as the DNA filaments are built up, to form the meshes of a network which limit the masses of chromatic material that take the shape of chromosomes characterized by regular fibrillar arches, at the 8–16 nuclei stage. In their centre, there is an axial structure which remains intact during the chromosomal segregation; its function during mitosis seems to be important: supplementary layers of arches appear at this level. — The progressive condensation of the chromosomes is correlated to the sporogenetic evolution of the nuclei, not to the different phases of the mitotic cycle. — The karyokinesis is brought about, during early stages, by mere splitting of the chromatic mass and of its envelope, and later one by separation into two lots of chromosomes. The segregation of these chromosomes is effected by partial intervention and growth of the envelope of the nucleus; there is no centromeric structure visible. At the end of divisions, the nucleus is almost entirely formed by its chromosomes. — The nucleolar structure, the karyokinesis, the structure of the nuclear envelope and the chromosomal cycle show the particularly high evolution of Noctiluca, within the Dinoflagellata.     

Hyperfixations costales bifocales découvertes à la TEP au fluorure (18F) de sodium lors de la stadification d’un cancer de la prostate

A prostate biopsy screening (PSA = 2 ng/mL) evidenced a prostate adenocarcinoma featuring a Gleason score of 8 (4 + 4) in a 62-year-old patient incurring an increased familial risk of prostate cancer. In order to stage the prostate adenocarcinoma, 2 PET scans were ordered. A PET/CT examination with FNa disclosed two hot spots on distinct ribs matching with heterogeneous sclerotic areas on low dose CT. A PET/CT examination with FDG disclosed a hypermetabolic focus of prostate left lobe and a weak intensity hypermetabolic focus of left ilio-obturator node but no bone metabolic abnormality. Staging was categorized distant (bone) metastatic disease upon FNa PET/CT findings. The patient benefited from pelvic external beam radiation therapy and hormone therapy. One year later, a PET/CT examination with FCH while patient was still on hormone therapy depicted a photopaenic area of prostate left lobe and a questionable hypermetabolic focus of right lobe but no bone metabolic abnormality. Retrospectively, bone lesions visible on PET with FNa were already conspicuous on plain X-rays and a CT examination performed a decade before. A new advice in a center specialized in bone and joint imaging suggested a benign condition for these protracted rib lesions even if the exact benign condition was elusive (fibrous dysplasia, aneurysmal bone cyst…). Two years later, the patient is symptom-free and his PSA level is 0.03 ng/mL.     

Etude autoradiographique de la proliferation et de la migration cellulaires au cours de la croissance larvaire de l'appareil visuel chez Aeshna cyanea Müll. (odonata : Aeshnidea)

Sites of cell proliferation in the ocular apparatus of Aeshna cyanea have been studied by an autoradiographic method (³H-thymidine). This technique was used to locate at the compound eye and optic lobe levels the zones of cellular multiplication and the migration of newly formed cells. In addition, the effect of the differential growth of the compound eye on the development of the optical lobe was studied. In the compound eye, two distinct levels of cell proliferation were revealed: the first one was the ocular budding zone itself, i.e. the ocular edge adjacent to the cephalic epidermis. A second mitotic focus, where the cells gather into ommatidial columns, was demonstrated. Thus, two closely related successive mitotic waves occur in the eye of this heterometabolous insect, whereas in holometabolous insects these two phases are much more distinct. Migration of ganglionic cells from the neuroblast masses, where they are formed, to the optical ganglions, where they differentiate, was also followed by this method. In addition, a differential growth of optic lobes was revealed: at the end of the nymphal life, the development was much greater in the posterior area of the optic lobes than in the anterior, although the numbers of cells produced in the neuroblast masses were, at the beginning, identical in both areas. This observation has been interpreted in the light of the experimental results.     

Étude complémentaire de la structure de trois galactoxyloglucanes (amyloïdes) de graines

D-Galacto-D-xylo-D-glucans (amyloids) from Balsamina, Tropaeolum, and Tamarindus seeds behave in a similar manner in the presence of various glycosidase preparations: slow depolymerization by enzymes from several germinated or non-germinated seeds, and hydrolysis into monosaccharides and oligosaccharides by commercial cellulase and hemicellulase preparations from fungi. A purified cellulase from Penicillium notatum gave a dialyzable fraction almost exclusively composed of α-D-xylopyranosyl-(1→6)-D-glucose residues and a nondialyzable fraction composed of chains of β-D-(1→4)[withsome (1→3)]-glucopyranosyl residues; β-D-galacto-pyranosyl-(1→2)-α-D-xylosyl groups are linked to some of the β-D-glucosyl residues at 0-6. The presence of (1→3)-linkages in the D-glucan chain of the Balsamina was verified by methylation and sequential periodate oxidation-borohydride reduction; the distribution of the substituents on the D-glucan chain is not regular. The main D-glucan backbone, where the β-D-glucosyl residues are partly linked at 0-6 to β-D-galactosyl-(1→2)-D-xylosyl groups, is linked to D-glucan chains where almost all the D-glucose units are linked at 0-6 by one α-D-xylosyl group. The presence of 3,6-di-O-methyl-D-glucose after permethylation and hydrolysis suggests that the xyloglucan chains are linked to 0-2 of the D-glucosyl units of the galactoxyloglucan backbone.     

Aristote (384–322): biologiste de la réproduction avant la lettre

Born in Chalcidice, Greece, in 384 BC and died in Chalcis in 322 BC, Aristotle, an Athenian philosopher, made considerable contributions to the fields of anatomy, zoology and biology. His research and texts on reproduction biology made a major contribution to the development of this discipline and Aristotle is rightly considered to be a pioneer in this field.     

Influence comparée de l'(±)-acide abscissique,de la coumarine,de l'acide p-coumarique et de certains de leurs dérivés sur la croissance de la première feuille de blé

Summary The activities of (±)-abscisic acid and a number of compounds derived from p-coumaric acid and coumarin and their interaction with gibberellic acid in the control of the elongation of the first wheat leaf are examined. (±)-Abscisic acid strongly inhibits leaf growth in the presence as well as in the absence of gibberellic acid, but the inhibition is greater in the presence of gibberellic acid (3 g/l already have an observable effect). Among other compounds, only ferulic acid and coumarin significantly reduce leaf elongation, and they are effective only at high concentrations (1.44 · 10^-4 M/l).     

Variations de quelques aclivités enzymatiques (peroxydase, catalase, AIA-oxydase) et de la teneur en polyphénols au cours de la germination de I'Orge. Influence de la kinétine

Peroxidase catalase, IAA-oxidase and polyphenol content of growing barley coleoptile. Effect of kinetin. - Kinetin strongly inhibits root and coleoptile growth of germinating barley in the dark. Treated coleoptiles become senescent before the untreated ones. Soluble proteins content, peroxidase, catalase and IAA-oxidase activity were greatly increased in treated coleoptiles while the level of polyphenols was reduced. These biochemical effects joined with the other property of kinetin to diminish α-amylase synthesis in the endosperm are discussed in relation to growth and in connection with the classic view of a cytokinin retarded senescence.     

Nouveaux genres de Squaliformes (Chondrichthyes) du Paléogène des Landes (Sud-Ouest de la France)

Résumé  Parmi les nombreux squaliformes récoltés dans le Lutétien des Landes (SO de la France), deux genres et espèces nouveaux ont été reconnus:Squaliodalatias weltoni n. gen. n. sp. etAngoumeius paradoxus n. gen. n. sp. La morphologie dentaire du premier permet de le rapprocher des Dalatiidae. Les relations phylétiques du second taxon sont pour 1’instant moins claires, en raison de sa denture supérieure inhabituelle pour un Dalatiiforme aussi évolué au niveau de la denture inférieure. Ces taxa nouveaux viennent enrichir nos connaissances sur un groupe encore mal connu à l’état fossile en raison de son habitat bathyal ainsi que sur la mise en place et la radiation, encore trop peu documentée, des faunes profondes.      

Les éperons stipulaires de la Glycine (Wisteria sinensis Sweet)

Summary InWisteria sinensis, two little spurs are found under the deciduous stipules. They are vascularized by fairly complex bends of both lateral bundles, in much the same way as the dorsal spur ofAsparagus leafscale is by the median.