Effet de la farnesylacetone sur les syntheses proteiques de l'ovaire chez le crabe Carcinus maenas

Summary

We have analysed in vitro the effect of farnesylacetone, a substance produced by the androgenic gland of Crustacea, in a concentration of 20 ng/ml, on the protein synthesis in the ovary of Carcinus maenas. In winter, the farneslyacetone seems to be ineffective; the incorporation of labelled precursor per mass unity is then related to the weight of the sample. In summer, an activation of protein synthesis can be observed. These results do not depend on ovary maturation and concern all the proteins of the gonad.     

Les ostracodes plio-pléistocènes de la côte orientale de la Péninsule du Cap Bon (Tunisie)

This article concerns the study of the ostracods of the Upper Pliocene-Lower Pleistocene sedimentary deposits cropping out along the south-eastern coast of the Cape Bon Peninsula (Tunisia, Hammamet region, Sidi Khelas section). Fourteen samples were taken along a thirty-two-meters thick sedimentary silico-clastic series. Seventy species of ostracods belonging to twenty-four genera were found. The autochthonous association, which originally lived in an environment located in the infralittoral and upper circalittoral stages of the benthic marine domain, is cyclically affected by inputs from the more superficial environments due to the presence of relatively well-developed lagoon and/or estuary environments in the surrounding coastal areas. Within the ostracod association, the presence of Bythocythere turgida – a true “northern guest” – is particularly significant. This species indicates that these sediments were deposited during the cold phases of the Early Pleistocene. Among the ostracods found, those belonging to the families Trachyleberididae, Hemicytheridae and Bythocytheridae, which are dominant and include particularly significant species from the environmental and paleoclimatic point of view, are systematically recorded and commented on. Some species that are probably new have been described and photographed, but are currently left in open nomenclature because of how few specimens have been found.     

Premiers cas de brachyptérisme dans le genre Sisyphus Latreille (Coleoptera,Scarabaeidae, Sisyphini)

Les espèces du genre Sisyphus Latreille, 1807, présentant des touffes de soies sur les élytres sont étudiées. Sept nouvelles espèces appartenant à ce groupe sont décrites, illustrées et comparées aux espèces proches: deux espèces aux ailes normalement développées, S. manni n. sp. et S. perissinottoi n. sp., et cinq espèces brachyptères, S. jossoi n. sp., S. janssensi n. sp., S. bouyeri n. sp., S. felschei n. sp. et S. usambaricus n. sp. Une autre espèce appartenant au groupe étudié, S. alveatus Boucomont, 1935, se révèle également être brachyptère. Elles constituent les premiers exemples de brachyptérisme au sein de ce genre. Une clé d’identification des espèces à touffes de soies sur les élytres est donnée.     

Effect of variable surrounding on species creation

We constructed a model of speciation from evolution in an ecosystem consisting of a limited amount of energy recources. The species possesses genetic information, which is inherited according to the rules of the Penna model of genetic evolution. The increase in the number of the individuals of each species depends on the quality of their genotypes and the available energy resources. The decrease in number of the individuals results from genetic death or maximum-age reaching by the individual. The amount of energy resources is represented by a solution of the differential logistic equation, where the growth rate of the amount of the energy resources has been modified to include the number of individuals from all species in the ecosystem under consideration. The fluctuating surrounding is modelled with the help of the function V(x, t) = 1/4 x4 + 1/2 b(t)x2, where x represents phenotype and the coefficient b(t) shows the cos(omega t) time dependence. The closer the value x of an individual to the minimum of V(x, t), the better adapted its genotype to the surrounding. We observed that the life span of the organisms strongly depends on the value of the frequency omega. It becomes shorter the more frequent the changes of the surrounding. However, there is a tendency for the species that have a higher value of the reproduction age aR to win the competition with the other species. Another observation is that small evolutionary changes of the inherited genetic information lead to spontaneous bursts of the evolutionary activity when many new species may appear in a short period.     

Microfaune du Paléocène de quelquessondages du Dôme du Sénégal occidental; observations sur les Ostracodes

The Paleocene of Western Senegal has shown amainly benthonic microfauna; the more characteristic elements of which are the Ostracoda: Cytherella (Cytherelloidea) aff. keijiMac Kenzie, Buntonia aff. attitogonensisApostolescu, Soudanella laciniosaApost., Quadracythere? lagaghiroboensisApost., Evisceratocythere cf. glabellaApost., Some of these species, which have been discovered in Senegal for the first time, have a large stratigraphic distribution. Effectively, they have been already found in Togo, Niger, Nigeria, even Lybia. Particularly, Soudanella laciniosa seems to be a very good Paleocene fossil at least in Africa, from the Mediterranean sea to the Gulf of Guinea. The benthonic Foraminifera are less abundant and badly preserved. In the same way as Ostracoda, they show species already known in the African Paleocene. The assemblage of the microfauna, in accordance with the sedimentological data, reveals the existence of a warm sea, in connection with the open sea, but very shallow, perhaps with periodical emersions (intertidal zone?).     

Plio-pleistocene mammals from Gidhniya village Western Nepal

Recently collected vertebrate fossils from the Himalayanfoothills of western Nepal comprise the first diverse Plio-Pleistocene mammal assemblage known from Nepal. Specimens representing Stegodon insignis, Elephas planifrons, Equus sivalensis, Hexaprotodon sivalensis, Cervus sp., and two taxa of bovids are present in this collection from Gidhniya Village. The Gidhniya assemblage is biostratigraphically correlated with the «Pinjor fauna of India and Pakistan; it is between 1.5 and 2.9 million years old.     

Cycle biologique d’Oecocecis guyonella (Lepidoptera : Gelechiidae), insecte galligène de Limoniastrum guyonianum (Plumbaginaceae), dans la région de Biskra (sud-est algérien)

Résumé

Le suivi du cycle biologique du Gelechiidae Oecocecis guyonella (Guenée, 1870) durant l’année 2018, sur le terrain et en laboratoire, a montré une bonne synchronisation entre le développement de cet insecte cécidogène et la phénologie de sa plante hôte, Limoniastrum guyonianum Boiss. En effet, dès l’entrée de cette Plumbaginaceae en période de croissance végétative, vers fin-janvier début-février suite aux premières poussées de sève causées par l’augmentation des températures, les larves de cet insecte commencent à éclore à partir des ?ufs pondus par les femelles à l’intérieur des tissus des jeunes tiges de la plante. L’alimentation des larves induit la formation des galles. Le développement larvaire se déroule entièrement à l’intérieur de ces galles, qui servent d’abri et de source alimentaire, sur une période de huit mois jusqu’à l’émergence des adultes à l’extérieur des galles, qui se produit de début octobre jusqu’à fin novembre.     

Ecologie des Dermestidae,une famille de Coléoptères nécrophages associée aux cadavres squelettisés

Lorsqu’un animal meurt, son cadavre forme un écosystème local instable et éphémère où différentes communautés d’insectes nécrophages vont se nourrir. Cette étude a pour but de caractériser les relations entre deux familles fréquentes en contextes médico-légal : les Diptères Calliphoridae et les Coléoptères Dermestidae. Des expériences de choix binaire (olfactomètres en T) et de prédation des Dermestes sur les larves de Diptères ont constitué le 1er axe de notre étude. Il en ressort que l’espèce D. maculatus (adultes et larves) n’exerce qu’une très faible prédation sur les larves de L. sericata. En absence de nourriture, les Dermestes sont néanmoins capables de prédater les pupes de L. sericata, et donc de faire disparaitre ces traces particulièrement importantes en entomologie médico-légale et en archéo-entomologie. Le second axe s’est focalisé sur les relations de compétition et d’agrégation entre D. maculatus et D. haemorrhoidalis. Les résultats obtenus n’ont pas mis en évidence de mécanismes de compétition ou d’exclusion entre ces deux espèces pourtant amenées à fréquenter simultanément le même habitat et à exploiter les mêmes ressources. Placées en condition de choix binaire (2 spots identiques), les 2 espèces s’agrègent ensemble. Mais le développement conjoint de ces 2 espèces sur une seule source de nourriture non limitante entraine une baisse significative du taux de survie chez les deux espèces. Au vu de ces résultats, nous avons conclu à la possibilité d’une coexistence de ces différentes espèces (L. sericata, D. maculatus et D. haemorrhoidalis) sur un cadavre.     

Siwalik synopsis: A long stratigraphic sequence for the Later Cenozoic of South Asia

The Tertiary sediments of northern Pakistan are an exceptional record of terrestrial sedimentation and represent most of Neogene time. Foremost is the Siwalik Group of the Potwar Plateau, for which multiple, superposed fossil levels span ∼18–6 Ma. Well-developed magnetostratigraphic control provides secure dating so that Siwalik fossil horizons may be interpolated into a time scale with resolution to 100,000 years. We describe the geographic setting of the Potwar, give an overview of the temporal distribution of faunas, and discuss changes in paleohabitat and paleoecology with coinciding faunal change, as seen from the Siwalik viewpoint. The long Siwalik biostratigraphy of many successive assemblages with its resolved time scale may be compared directly with other well-dated sequences. Immigrant arrival and timing of faunal change may be traced. The basins of the Iberian Peninsula show somewhat different timing of introduction of hipparionine horses, and faunal turnover in the Siwaliks clearly precedes the Vallesian crisis in Spain. In contrast to the increasingly seasonal precipitation of the late Miocene Potwar, the paleohabitat of coeval North China appears to have been moist and equable, with high diversity faunas. Continued development and comparison of resolved Neogene records allow increasing resolution of the patterns of faunal change on regional to global levels.     

Climatic and environmental conditions from the Neolithic to the Bronze Age (7000–3000 BP) in the Iberian Peninsula assessed using small-mammal assemblages

We have analyzed the palaeoenvironment and palaeoclimate of the beginning of the Holocene in the Iberian Peninsula on the basis of the small-mammal assemblages from three sites within the geography of the Iberian Peninsula: Mirador (Sierra de Atapuerca, Burgos), Colomera (Sant Esteve de la Sarga, Lleida) and Valdavara-1 (Becerreá, Lugo). These associations reveal that the palaeoenvironment was more humid than today in the sites under study, and the landscape was dominated by woodland and woodland margins in all the studied layers. Further, the climatic conditions were stable, but with winters colder than at present, above all in the Mediterranean area. Finally, our data have been compared with other environmental and climatic proxies, showing that human activities exerted little impact on the palaeoenvironmental conditions that occurred from 7000 to 3000 BP in the Iberian Peninsula.     

Stabilité du polymorphisme enzymatique dans les populations d''un Lépidoptère migrant,Agrotis ipsilon

Homogeneous population structure in a migrant Lepidoptera, Agrotis ipsilon. Light trapping of Agrotis ipsilon (Lepidoptera, Noctuidae) on various passes of the Alps and Pyrénées exhibited wide range movements between overwintering and aestivation areas. Electrophoretic analysis of samples taken in the Cantons of Vaud and Tessin (Switzerland), in the Rhône Delta (Southern France), and on passes of the Alps and Pyrénées, showed a great temporal and spatial homogeneity of allele frequencies (Fst values ranging from 0.002 to 0.013, and genetic distances from 0 to 0.004). These results support the hypothesis of a high level of gene flow. However, the occurrence during some years of high Fis values, might be explained by mixtures of populations that had undergone selection or went through a bottle-neck.     

Analyse pollinique des dépôts lacustres miocènes de Fabrègues(Aups,Var, France): Intérêt paléoclimatique

The pollen flora of Fabrègues lacustrine deposits suggests a sclerophyllous forest qualitatively comparable with the one known from the Lower-Middle Miocene of the Languedoc. However, it reveals a less dense forest. Does this pollen flora reflect distinct edaphic environments or is it the result of a climatic change? These two hypothese are discussed.     

Dehydrogenases reducing NAD+ in the presence of D (-) 3- phosphoglycerate in mycobacteria (BCG, H37Ra, M. phlei)]

Referring to the elution volume on a Sephadex G-150 column only one specific peak is obtained, the same for the BCG, H37Ra and Mycobacterium phlei strains grown on Sauton synthetic medium. Some properties of these partially purified dehydrogenases are studied (conservation and dialysis in media of different salt concentrations, equilibrium constant, Km, heat stability). All enzyme preparations from tubercle bacilli (BCG, H37Ra) are readily inactivated by heat and are very unstable in solutions of low ionic strength. In contrast, under the same experimental conditions, all enzyme samples from M. phlei are, comparatively, much more stable towards these factors [heat, salt (potassium phosphate, NaCl) concentration].     

Biogeography and chronology of the Eurasian extinct rhinoceros Stephanorhinus etruscus (Mammalia,Rhinocerotidae)

Stephanorhinus etruscus is one of the most abundantly recorded and better known Eurasian Early Pleistocene rhinoceroses. Nevertheless, the first and last appearances of this species, as well as its paleogeographic distribution, are controversial and debated in literature. S. etruscus is documented since the latest Pliocene in Spain (Las Higueruelas), Italy (Montopoli and Castelnuovo di Barardenga), France (Perrier–Les Étouaires) and Romania (Iar??–Cariera Veche). During the Early Pleistocene, S. etruscus occurred in several Spanish, French and Italian localities, as well as in The Netherlands (e.g., Tegelen), Germany (e.g., Thiede), Greece (e.g., Aivaliki) and Israel (e.g., Ubeidiya). The last appearance of S. etruscus in Eurasia is debatable. Etruscan rhino populations survived till the Jaramillo subchrone (around 1.1 Ma) in France (Bois-de-Riquet), Romania (Betfia XII) and Hungary (Osztramos 2 and 8), and close to the early–middle Pleistocene transition in Spain (Cueva Victoria, Huéscar 1, Atapuerca TD4, TD6 and TD8), and Italy (Monte delle Piche).