Études du Paléolithique du Japon à partir des téphras

Many studies and discussions have been made on the problem of when the earliest human beings appeared in Japan. In general, hominid fossils in the latest Pleistocene are not preserved except for coralline limestone sequence in Ryukyu islands, but earlier Paleolithic tools were excavated from volcanic ash soil with a ¹⁴C age of about 30,000–35,000 yr. BP or younger at several archeological sites in almost all Japan. Recent studies, however, show a need for revision and refinement of these ages because calibration techniques have progressed from conventional to calendar ages and high-resolution oxygen isotope chronology has given a global standard sequence. Aïra-Tn tephra (AT), the most important time-marker of the Paleolithic age in Japan, was formerly dated at 21,000–22,000 yr ¹⁴C BP by conventional radiocarbon methods but was dated again at ca. 24,500 yr ¹⁴C BP by accelerated mass spectrometry radiocarbon methods. However, it has been further calibrated to a high-resolution calendar age of 30,000 cal yr. by varve chronology of lake sediments of Suigetsu of central Japan, well matched with combined date between oxygen isotope dates based and calibration from AMS radiocarbon dates. As the earliest Paleolithic tools in south Kanto are found in volcanic ash soil significantly below AT ash and above Sambe-Ikeda ash (SI, ca.46 ka), just above the oxygen isotopic stage 3.3, they are estimated to be dated slightly older than 40 ka. Palaeo-environment at that time is estimated mild to cool climate and relatively low sea level after the oxygen isotope stage 3.3. Sill land bridges between Japan islands and continents have not been formed at major straits. We have not yet obtained useful data for calibration older than ca. 45 ka. Also, correlation of oxygen isotopic fluctuation with the terrestrial sequences is incomplete in Stage 3.     

Structure du noyau des Blastodinium (Dinoflagellés parasites)

Résumé Les observations photoniques et ultramicroscopiques concernant les Blastodinium, parasites de Copépodes, étudiés à tous les stades de leur développement intra-intestinal nous ont apporté les résultats suivants:Le Trophocyte subit de profondes transformations nucléaires avant de commencer à se diviser (éndettement nucléolaire et passage des grains ribonucléoprotéiques dans le cytoplasme); les sphères archoplasmiques liées aux noyaux se divisent avant eux et apportent leur contribution dans les synthèses membranaires; la division nucléaire est une pleuromitose simple, sans cinétochores et sans centrioles: on peut observer tous les stades définis de, la mitose, exceptée l'interphase; la métaphase est très difficile à saisir, surtout dans les espèces à mitoses accélérées. Les faisceaux de microtubules contenus dans les plasmodendrites qui perforent les noyaux toujours en mitoses au cours de la sporogenèse, ne sont jamais en contact avec les chromosomes; nous avons entrevu leur rôle dans la cyclose hyaloplasmique. Durant les phénomènes sporogenétiques, un cycle régulier de condensation chromosomique s'effectue, sans perte de DNA. Dans les stades peu condensés, l'arrangement fibrillaire des chromosomes est inorganisé, puis ceux-ci montrent un agencement en séries d'arceaux réguliers qui disparaît dans les stades les plus condensés.L'enveloppe nucléaire joue un rôle prépondérant dans la traction, l'orientation et la ségrégation du matériel chromosomique. Nous avons recherché également une série d'explications concernant le déterminisme des phénomènes de condensation chromatique.Dans cet exemple précis, noyaux et phénomènes mitotiques démontrent parfaitement cette situation intermédiaire des Dinoflagellés, entre Bactéries et Eucaryotes.

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Nuclear structures of Blastodinium Chatton (parasitic dinoflagellates)Division and chromatic Condensation

The mitotic mechanism in Blastodinium Chatton has been studied by photonic and electronic microscopy. Divisions of the archoplasmic spheres precede that of the nuclei and their movements are interconnected. Stages of mitosis follow one another without interphase; they are telescoped, which makes the study of the chromosome cycle more difficult. Progressive condensation of nuclei and chromosomes takes place in the various sporogenetic layers within the same parasite. Cytophotometric measurements show that there is no loss of DNA during successive mitosis. The nuclear envelope plays an important part in the traction, orientation and segregation of the chromosomes. The cytoplasmic invagination which perforate the nuclei contain considerable masses of microtubules whose role in the activation of the hyaloplasmic cyclosis and membranous synthesis is suggested.—In longitudinal section, the chromosomes show a fibrillar arrangement in regular arches in the non-condensed stages and irregular arches in more condensed stages, with a lesser diameter.—The type of nuclear division is a very simple pleuromitosis without kinetochores and centrioles; the role of the nuclear envelope in the chromosomal mechanism appears to be preponderant.

     

Eco-éthologie des nouveaux ravageurs invasifs des eucalyptus du Maroc

Trois nouveaux ravageurs invasifs ont été observés au cours de cette dernière décennie dans les peuplements d’eucalyptus de la région du Gharb au Maroc. Un premier gallicole, Leptocybe invasa Fisher & La Salle 2004 (Hymenoptera: Eulophidae), a été repéré dès 2002, tandis que son parasitoïde Megastigmus sp. (Chalcidoidea: Torymidae) a été identifié en 2009. Les deux autres ravageurs, Ctenarytaina eucalypti (Maskell 1890) et Glycaspis brimblecombei Moore 1964 (Hemiptera: Psyllidae), ont été découverts respectivement en 2008 et 2009. Quelques paramètres bio-écologiques relatifs au développement de L. invasa ont été mesurés au laboratoire et sur le terrain, tandis que le taux d’infestation de jeunes eucalyptus a été suivi pendant trois années successives. Les stratégies de lutte envisagées contre ces nouveaux ravageurs sont discutées.     

Interprétation paléogéographique des données palynologiques du site du Paléolithique supérieur de Mezhyrich (Ukraine)

The results of palynological study of the Upper Paleolithic Mezhyrich site in central Ukraine are presented. Four local pollen zones were identified. The results of the palynological investigations allow us to hypothesize that the plant cover during Upper Paleolithic had a mosaic structure. The pollen record shows the presence of a few tree species with the predominance of herbaceous plants. We suggest that the river valleys and other local favorable sites were natural refugia where forest elements could survive even during the Last Glacial Maximum. These favorable landscapes to the existence of prehistoric hunters may have persisted during the Last Pleniglacial.     

Biostratigraphie des Miospores et des Chitinozoaires du Silurien supérieur et du Dévonien dans le bassin d'Illizi (S.E. du Sahara algérien)

Core samples from the Illizi basin yielded well preservedmiospores and Chitinozoa. The detailed study of the range of these microfossils allows accurate age assignment for upper Silurian and Devonian subsurface strata of the southeastern part of the algerian Sahara. On the other hand, these biostratigraphical data demonstrate the occurrence of important stratigraphical gaps related to recurrent emersions.     

Chimiothérapie des tumeurs germinales du testicule

Germ cell tumours of the testis represent a model of curable disease, even in advanced stages. Cisplatinbased combination chemotherapy followed by surgical removal of residual metastatic disease has dramatically improved the prognosis of these patients, as about 90% of them are currently cured. The standard cytotoxic drugs used in first-line treatment are bleomycin, etoposide and cisplatin (the so-called BEP regimen). Treatment strategy is based on assessment of risk factors. Three cycles are generally used in patients with advanced pure seminoma or good-risk metastatic non-seminomatous tumours. Four cycles are required in patients with intermediate-or poor-risk metastatic non-seminomatous tumours, while two cycles of BEP constitute a safe and effective treatment option in early-stage tumours but with a high-risk of metastatic spread defined by a high percentage of embryonal carcinoma and/or the presence of vascular invasion. Cure rates as high as 90% are achieved provided risk factor strategies are accurately applied and standard treatment modalities are respected. All protocol violations can decrease the expected efficacy or induce unnecessary toxicity.     

Les sclérobiontes des huîtres du Cénomanien supérieur du Mans (Sarthe,France)

Oysters of the Marnes à Pycnodonte biauriculata Formation, Upper Cenomanian (Guerangeri biozone) were significantly sampled in building works within the town of Le Mans (Sarthe, France). They are colonized by episkeletobionts (encrusting organisms) and endoskeletobionts (boring and bioeroding organisms). First ones include bivalves, polychaetes, foraminiferans and bryozoans. Second ones are represented by about fifteen ichnotaxa, the producers of which, when they are known, belong to ten taxa. The oysters, some of which have a large fixation surface, are allochtonous or at least parautochtonous. The settlement of sclerobionts began when the oysters were alive (Entobia isp.) and continued post-mortem on isolated valves, transported in their final depositional environment (Gnathichnus pentax). The significance of the coexistence of both Entobia and Gnathichnus ichnocoenosis is discussed.     

La faune des bourdons (Hymenoptera: Apidae) du Parc National des Pyrénées occidentales et des zones adjacentes

Les bourdons constituent l’un des groupes de pollinisateurs les plus importants dans les écosystèmes montagnards. Cependant, la faune des bourdons du Parc National des Pyrénées occidentales (PNPO) est encore peu connue. Pendant trois ans, la faune des bourdons du Parc National des Pyrénées occidentales a fait l’objet d’une surveillance. Les inventaires effectués en juillet- août 2002, 2003 et 2005 ont permis l’observation de 5889 spécimens de bourdons de 29 espèces. Si l’on tient compte des observations des cinquante dernières années, la diversité spécifique du parc s’élève à 30 espèces de bourdons. Une telle diversité spécifique est remarquable et comparable à celle observée dans d’autres secteurs du massif pyrénéen. La faible différence entre les faunes du Parc et des réserves naturelles d’Eyne et de Nohèdes (Pyrénées-Orientales) rend compte du caractère exceptionnellement diversifié de la faune des bourdons du massif pyrénéen en général.     

Ultrastructure des cellules germinales au cours du développement embryonnaire du Lézard vivipare (Lacerta vivipara Jacquin)

Résumé Les gonocytes primaires sont relativement pauvres en polysomes et l'ergastoplasme granulaire est très réduit. Le reticulum endoplasmique de type lisse se développe au cours du développement embryonnaire. L'appareil de Golgi est bien représenté et localisé au niveau de la calotte juxtanucléaire mitochondriale. Les liposomes cytoplasmiques sont très nombreux.Cette étude précise la structure du nucléole «annulaire» et de la «masse paranucléolaire» observés en microscopic photonique. Des modifications nucléolaires sont constatées au cours du développement embryonnaire. Certains aspects ultrastructuraux sont vraisemblablement en rapport avec le déplacement autonome des gonocytes. La signification physiologique du nucléole «annulaire» et de la «masse paranucléolaire» est envisagée.

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Ultrastructural study on the primordial germ cells during embryonic development of Lacerta vivipara Jacquin

Summary The primordial germ cells of Lacerta vivipara have relatively few free polysomes and little ergastoplasm. Smooth endoplasmic reticulum increases during embryonic development. The Golgi apparatus is well developed and lies close to the mitochondrial juxtanuclear cap. This study shows the ultrastructure of the ring-shaped nucleoli and the masse paranucléolaire. Modifications in nucleolar structure are observed during embryonic development. Some ultrastructural features are probably related to the ameboid movement of the primordial germ cells. The physiological meaning of the ring-shaped nucleoli and the masse paranucléolaire is considered.

Avec la collaboration technique de Mme. M. Hubert.     

Étude paléontologique du genre Sabinia (Rudiste à canaux)des récifs du Campanien de Tunisie

Campanian rudist reefs of Central Tunisia are rich in pallial-canal rudists, belonging to the genus Sabinia. The Djebel Serraguia layer shows well-preserved samples allowing to make a detailed paleontologic study. A new sub species of a previously observed species from the Maastrichtian of Yugoslavia and Turkey is described. Identified for the first time on the african margins, this new taxon gives interesting data concerning systematic and evolution of the genus Sabinia, as well as the relationships between reef provinces during the Upper Senonian. The biosedimentologic role of Sabinia within tunisian reefs is pointed out.     

Métabolomique et imagerie TEP-FDG des cancers du sein

Cancer metabolism is an essential aspect of tumorogenesis, as cancer cells have increased energy requirements in comparison to normal cells. Metabolomic techniques can provide quantitative data for a large number of small molecules in tissues and enable the analysis of multiple intricate metabolic pathways. Positron emission tomography (PET) using ¹⁸F-Fluorodeoxyglucose (FDG) enables in vivo analysis of glycolysis and is widely used in oncology. High tumor FDG uptake is a prognostic factor in breast cancer and has been associated with tumor aggressively. Seventy breast cancer samples obtained from untreated patients who had underwent FDG-PET imagery were analyzed through an untargeted metabolomic approach using liquid chromatography-mass spectroscopy (LC-MS) to study possible correlations between metabolomic data and FDG uptake. Tumors were split into two groups depending on avidity for FDG as measured with PET. The Compound Discoverer 4.0 software enabled identification of 854 metabolites. PLSDA based models predicted FDG uptake with an accuracy ranging from 0,73 to 0,77. Selected metabolites varied depending on the use of scaling or log transformation. Metabolites correlated with tumor FDG uptake were, among others, glutathione, amino-acids such as glutamate, proline or tyrosine, L-acetyl-carnitine, metabolites from the kynurenine pathway such as L-kynurenine or formyl-kynurenine and polyamines such as N1,N12-diacetylspermine or N1-acetylspermine. These metabolites have been previously shown to reflect cancer aggressivity. The correlation between the glycolytic pathway activation and tumor FDG uptake could not be directly assessed but indirect signs showed a higher glycolytic activity in tumours presenting a higher FDG uptake. Studying new metabolites identified through this process could enable a better understanding of tumor metabolism and identification of new biomarkers.     

Hydrolyse enzymatique des protéines par les bactéries du rumen

The hydrolysis of proteins in the rumen is a process brought about mainly by bacteria, of which many species produce proteases. The majority of endopeptidases are cysteine proteases, whereas exopeptidases are mainly aminopeptidases. Prevotella ruminicola is distinguished from other bacterial species by its capacity to produce dipeptidases such as type I dipeptidyl aminopeptidase. The mechanisms controlling the synthesis of endo- and exopeptidases have been little studied. Enzyme production seems to depend on the concentrations of peptides, amino acids and carbohydrates. Proteolytic activity varies in relation to pH, and the concentrations of ions and phenolic compounds. Various works have shown that hydrolysis of a protein by enzymes depends on its three-dimensional structure and possible bonding to non-protein structures. These properties determine the peptide and amino acid concentrations that occur in the rumen. The molecular weight, hydrophobic property and primary structure of the peptides are the main factors that affect the hydrolysis and/or uptake of these compounds by rumen bacteria. The methodological problems inherent to assaying these compounds do however lead to current divergences of opinion concerning the physico-chemical characteristics of the peptides that escape rumen fermentation.     

Les occupations humaines du Nord du Maroc,du Paléolithique Moyen et du Paléolithique Supérieur. Nouvelles données sur la base des recherches archéologiques des projets de 2005 à 2020

In this work, we present a synthetic panorama of the human occupations of northern Morocco, with an emphasis on the association of anthropological with cultural records, within the framework of the Middle Palaeolithic (MSA) and the Upper Palaeolithic. We also present the projects developed over the past 15 years and the most interesting results we have obtained. And we conclude bay providing some reflections on the cultural and historical evaluation of the archaeological records from the Tetouan region in the Middle and the Upper Palaeolithic phases.     

Signification paléoécologique et paléogéographique des bivalves du Carbonifère inférieur du bassin d’Ancenis (Massif armoricain)

Palaeoecological and palaeogeographical inferences from Early Carboniferous bivalves of the Ancenis Basin (Variscan belt, France). In the basal part of the Ancenis Formation, of Dinantian age, greenish to purple mudstones display a few bivalves, assigned to the genera Lithophaga, Modiolus, and Naiadites. Because Naiadites is considered to be a non-marine bivalve, and is only previously reported in Scotland in Dinantian rocks, a brackish environment can be assumed for the Ancenis Basin during the Early Carboniferous. To cite this article: M. Ballèvre, H. Lardeux, C. R. Palevol 4 (2005).     

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.     

Les otolithes des Téléostéens du Plio-Pleistocène belge

The study of approximately twenty three thousand otoliths from Plio-Pleistocene sites in the harbour region of Antwerp, as well as a critical revision of already published material allowed us to identify a teleostean fauna with fourty seven species (including two subspecies and seven species in open nomenclature). Two of these, Ophidion springeri and Uranoscopus septentrionalis are new to science. The fauna is typical for coastal waters slightly warmer than those of the actual North Sea and caracterized by the predominance of Gadidae. Biostratigraphically this fauna is well individualized with respect to preceeding ones (only seven species in common with the Miocene fauna) and those following twenty-three species in common with the extant fauna). The following biostratigraphical subdivision has been recognized in the Upper Miocene and the Plio-Pleistocene of the Antwerp region: (1) an association with «genus? Macrouridarum labiatus, Trisopterus sculptus, Gadiculus benedeni and Trisopterus luscus spectabilis, in the Sands of Deurne (Upper Miocene); (2) an association with Gadiculus benedeni and Merlangius pseudaeglephinus, in the Formation of Kattendijk (Pliocene); (3) an association with Gadiculus verticalis and Merlangius pseudaeglefinus in the Formation of Lillo (Plio-Pleistocene); (4) an association with Gadus morhua and Merlangius pseudaeglefinus in the so called «Icenian deposits not present in Belgium but found in the Netherlands.     

Pratiques funéraires et recrutement : reprise d’étude des collections osseuses issues des dolmens du Languedoc oriental et sud des Cévennes à la fin du Néolithique

Collective burials were the main and most widespread funerary practice at the end of the Neolithic, beginning of the Bronze Age in the south of France. Megalithic monuments required a huge investment of time and labor. According to ethnographic studies, these monumental tombs are generally built and managed collectively. One can therefore wonder who was buried inside these structures because several archaeological studies indicate that access to these tombs can sometimes be restricted to certain members of the population. Indeed, ethnography highlights that access to certain tombs can be structured by variables such as kinship, social status, etc. While previous studies have mainly focused on the architecture and function of these monuments, this article focuses on the process of deposition of human remains and the characterization of the population buried inside these monuments. Since 2012, a project has been undertaken on the dolmens of the south of France in order to discuss funerary practices and to compare them with data from other archaeosciences to rediscuss the funerary traditions in place at the end of the Neolithic, the beginning of the Bronze Age.