Observations nouvelles sur les otolithes des Téléostéens du Calcaire Grossier (Eocène du bassin de Paris)

An important new collection of otoliths from theCalcaire Grossier of the Paris Basin, as well as a critical review of already published material is studied and reveals the presence of 56 species. Five of these are new: Muraenesox spatulus, Genus Synodontidarum intermedius, Genus Ophidiidarum spinosus, Chanda bohlkei and Mene sekharani. The assemblage is indicative of tropical to subtropical marine and neritic environment with solid bottom. Biogeographically, it shows affinities with the recent Indo-pacific fauna. The association of the sites at Fercourt and Château-Rouge is clearly different from the one found at the sites of Condé-en-Brie and Damery, as it is less littoral than the second association mentioned.     

Expression in vitro du gène de l'aromatase dans les cellules testiculaires du rat

The ability of the male gonad to convert androgens into estrogens is well known ; the microsomal enzymatic complex involved in this transformation is named aromatase and is composed of a specific cytochrome P450 aromatase (P450arom) and a ubiquitous reductase. Using a highly specific RT-PCR method we have measured the amount of P450arom mRNA in purified Leydig and Sertoli cells prepared from 20, 40 and 70–80 day-old rats. The amount of P450arom mRNA in the Leydig cells is independent of age (40 × 10⁻³ attomoles/μg of total RNA); in contrast, in the immature rat Sertoli cells, after 5 days of culture the amount of P450arom mRNA is 20-fold lower when compared to that of 20-day-old rat Sertoli cells (71 × 10⁻³ attomoles/μg of total RNA). Nevertheless, irrespective of the age, the addition of either FSH or dbcAMP for 6 h increases the level of P450arom mRNA in the rat Sertoli cell preparations. Therefore, we evidenced that during testicular maturation not only the Leydig cells but also the Sertoli cells of the rat have the capacity to express the gene for cytochrome P450 aromatase.     

Classification des souches du groupeBacillus thuringiensis par la détermination de l'antigène flagellaire

Summary The serological study of 26 new strains ofBacillus thuringiensis (of which the biochemical features are also given) makes it possible to classify these strains into: 1^o Strains which are in concordance with the six serotypes previously described. 2^o Strains which have a new H antigen. Here, we describe two new serotypes: serotype 7 (aizawai), serotype 8 (morrisoni). On the other hand, the serological study of five new strains ofB. thuringiensis belonging to serotype 4 shows that the H₄ antigen must be divided into ?sub-factors?: ?4 a, 4b? to be found in the strains sotto, dendrolimus, T.84-A, L (Grig) and ?4 a, 4 c? to be found in the strains Pil 94, 1748 and Rhodesia. Table 6 gives the present statute of theB. thuringiensis strains' classification by the flagellar agglutination technic.

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Avec la collaboration technique deM. Lechevallier etT. Le Borgne. Nous remercions vivement les collègues qui ont bien voulu nous adresser des cultures et nous nous tenons à la disposition de tous ceux qui seraient intéresés par la détermination de l'antigène H de leurs souches. Nous remercions également notre collègueLe Minor pour ses précieux conseils.     

Stimulation du potentiel de dégradation dans les eaux marines profondes par les bactéries barotolérantes colonisant les fèces du plancton migrateur

At a depth of 1 150 m in the northwest Mediterranean, amino acid uptake and bacterial biomass production rates increased, in a 12-day time interval, 5- and 30-fold, respectively. Simultaneously, bacterial response to pressure changes evolved from barophilic to barotolerant. During the same period, scanning electron microscope observations and in situ observations using Underwater Video Profiler showed a 2-fold increase in particle concentrations, mainly due to faecal pellet production by zooplankton. This input, nutrient rich and largely colonized with bacteria unaffected by pressure variations since they originated from organisms that regularly migrate up and down through the water column, could produce such microbial activity peaking in the deep water masses.     

Synthèse biostratigraphique du plio-pléistocène de Guadix-Baza (Province de Granada,Sud-Est de l'Espagne)

In the Guadix-Baza basin, a continental sequence 0214 ranging from the Upper Miocene (Upper Turolian) to the Middle Pleistocene (Cromerian) has been established. An essay of biozonation by means of the Rodent succession is proposed, based on the following biozones: Trilophomys castroi, Mimomys occitanus, Mimomys cappetai, Mimomys cf. reidi, Mimomys ostramosensis, Allophaiomys pliocaenicus, Mimomys savini and Arvicola cantiana.     

Une nouvelle espèce d'Apodemus (Rodentia,Mammalia)du Pliocène de la dépression de Guadix-Baza (Grenade,Espagne)

This paper describes a new species of Apodemus,A. agustii, a Middle Pliocene Muridae from the Guadix-Baza basin. Its morphology is far from that postulated as more frequent in Apodemus: its molars crowns are relatively high: there is no connection between t6 and t9 in M¹ and M². Taking in account this and its age, it is placed in an evolutionary branch, convergent with “Rhagapodemus” morphotype.     

Suoidea du Miocène inférieur de Laugnac (Lot-et-Garonne, France)

The fossil vertebrate locality of Laugnac is the type locality of the Neogene mammalian zone MN2b. It has yielded many remains of Suoidea belonging to two different genera.Xenohyus venitor is characterized by its large size and especially its large central upper incisors, I1/ and I2/. It is quite difficult to know its phyletic relationships because the material is not abundant.Hyotherium cf.meisneri is more abundant with a quite good skull, pieces of skull, jaws and isolated teeth. It belongs to a peculiar lineage different from that ofH. major from Saint Gérand-le-Puy, France. It has some similarities withAureliachoerus aurelianensis from later geological levels (MN3-MN5).     

Les premiers vertébrés et les premières étapes de l’évolution du crâne

The earliest vertebrates and the first steps of the evolution of the skull. Vertebrates are one of the few metazoan taxa, which display a well-corroborated phylogenetic pattern, a good and anatomically informative fossil record, and a relatively slow ontogenetic development. They are thus a favourite taxon for illustrating evolution as a historical process, although the stem of the vertebrate tree remains poorly documented by fossils, except for some Early Cambrian forms. Therefore, the characterization of the vertebrates now rests essentially on a small number of developmental characters, mostly involved in the rise of the skull, and whose precursors may occur in other chordates. The tree of the crown-group vertebrates also shows some major morphological gaps due to early extinctions, but a number of Palaeozoic stem gnathostome taxa helps in documenting the agnathan-gnathostome evolutionary transition. However, stem cyclostomes remain elusive.     

Etude ultrastructurale de la dégénérescence cellulaire dans la glande androgène du Crabe Ocypode quadrata (Fabricius)

Résumé L'étude ultrastructurale des glandes androgènes du Crabe Ocypode quadrata (Fabr.) révèle l'existence de processus involutifs entraînant une autodestruction cellulaire totale. Cette lyse se produit en des zones non localisées des glandes et n'affecte pas l'activité spermatogénétique du Crabe considéré de plus, la coexistence de cellules en dégénérescence avec des cellules normales traduit un asynchronisme cellulaire.Les différentes modifications conduisant à la dégénérescence ont été décrites: dégranulation de l'ergastoplasme, développement important du réticulum endoplasmique, vacuolisation des mitochondries, différenciation de jonctions cellulaires d'un type particulier, formations de «corps vacuolaires» et de vacuoles autolytiques puis de corps résiduels précédant les processus de fragmentation cellulaire et de pycnose nucléaire. Bien qu'il n'y ait jamais une régression totale des glandes androgènes, ces modifications rappellent celles qui surviennent après la métamorphose dans les glandes de mue des Insectes.La signification physiologique de la dégénérescence cellulaire est discutée.

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Ultrastructural study of cellular degeneration in the androgenic gland of the ghost crab, Ocypode quadrata (Fabr.)

Summary Electron microscopic examination of the androgenic glands of the ghost crab Ocypode quadrata (Fabr.) reveals the existence of involutive processes leading to complete cellular breakdown. This autolysis occurs in non-localized areas of the glands and does not affect the spermatogenetic activity of the crab studied; further, the coexistence of degenerative cells with normal cells shows a cellular asynchronism.The different modifications leading to degeneration have been described: substitution of rough-surfaced endoplasmic reticulum by an important development of smooth reticulum, vaculolization of mitochondria, differentiation of a particular type of cellular junctions, elaboration of vacuolar bodies and autolytic vacuoles and then of residual bodies preceding processes of cellular fragmentation and nuclear pyknosis. Although there is never a complete regression of the androgenic glands, these modifications resemble those which take place in the prothoracic glands of insects after metamorphosis.The physiological significance of the cellular degeneration is discussed.

Nos remerciements vont au Dr. Costlow, Directeur du Duke Marine Laboratory pour les facilités de travail mises à notre disposition et à Mme Charniaux-Cotton pour son analyse critique des résultats. Nous sommes également reconnaissante au Personnel de Microscopie électronique pour son aide technique.     

Fréquences de la mutation Δ32 du gène du corécepteur CCR5 dans les différentes régions françaises

We studied the frequency of the coreceptor CCR5 gene Δ32 mutation on 1836 DNA samples originating from ten French regions. This mutation confers, in the homozygous state, resistance to HIV-1 infection. For the whole territory, the mean percentage presence of the Δ32 mutation is 9.2 %. The mutation is statistically more frequent in the north (11.2 %) than in the south (6.3 %) of the country; this différenciation corresponds probably to a gradient of decreasing frequencies of the Δ32 mutation in Europe.     

Proposition de reconstitution du deuxième crâne d’Homo erectus de Yunxian (Chine)

A proposal of reconstruction of the second Homo erectus skull from Yunxian (China). In 1989 and 1990, two Homo erectus crania were recovered from Yunxian (Hubei province) in archaeological levels dated to more than 780 000 years. Considered along with Lantian, these skulls represent the oldest human remains discovered in China to date, constituting important palaeontological finds. Nevertheless, the crania were badly deformed during the course of fossilization, necessitating extensive cranial reconstruction. Of the two crania, only Yunxian II was in sufficient condition to carry out this reconstruction. Using sophisticated techniques only recently applied in human palaeontology, including computed tomography and rapid prototyping, and incorporating taphonomic and morphometrically-based hypotheses, we were able to correct virtually the deformation and to produce a 3D prototype of Yunxian II. To cite this article: A. Vialet et al., C. R. Palevol 4 (2005).     

Cellules riches en glycogène dans l'épendyme du ventricule latéral du cerveau de rat

Summary The ependyma of the lateral ventricle of the rat brain was investigated at different ages from 20 days to adulthood.A particular cell type occurs in the external wall of the ventricle, where the proliferative subependymal layer is present. These cells found at all ages studied, are characterized by a high content of glycogen, and a structure different of typical ependymal cells.A large number of nerve endings is situated in close vicinity of these cells, either free in the ventricle lumen, or sometimes ensheathed in the cells. No synapse was found between these endings an the glycogen-rich cells.These glycogen-rich cells undergo several modifications with age: their glycogen content is reduced in the adult, and they acquire a few cilia and gliofilaments. It is suggested that they represent a transitory differentiation of the ependyma, functionally linked with the proliferative subependymal layer.

     

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.     

Première biozonation du Pléistocène Européen,principal résultat biostratigraphique de l'étude des Rhinocerotidae (Mammalia,Perissodactyla) du Miocène terminal au Pléistocène supérieur d'Europe Occidentale

For the Uppermost Miocene the already known zones MN 9 to MN 13 are used without any change; they prove to be particularly useful for the study of fossil rhinocerotids. The Plio-Villafranchian age corresponds to the zones 14 to 19, the definition of the first five being completed and the last being new. Middle to Upper Pleistocene age deals with the zones 20 to 26, all being new and defined following the same principles.     

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.      

Une nouvelle espèce du genre Bohlinia (Mammalia,Giraffidae) du Miocène supérieur de Toros-Menalla,Tchad

New Giraffidae specimens discovered from the Late Miocene fossiliferous sector of Toros-Menalla (northern Chad) are described. These specimens are assigned to Bohlinia, a genus known so far only in some Late Miocene localities of Eurasia. This is the first occurrence of the genus in Africa. Analysis of the material allows us to describe a new species of giraffid, Bohlinia adoumi n. sp., probably close to the Eurasian forms.