Action de la flore microbienne du tractus digestif sur la biosynthese de l'acide cholique chez le rat

Axenic and holoxenic (conventional) rats were fed a diet containing trace amounts of [2,4-³H]cholic and [24-¹⁴C]chenodeoxycholic acids. In the feces of both groups of rats, the percentage of labelled bile acids which were ³H-labelled was slightly different. In the experimental conditions used, the intestinal microflora only slightly modified the synthesis of 12α-hydroxylated bile acids.     

Role des spermatheques dans l'utilisation du sperme et la stimulation de l'ovogenese chez Drosophila melanogaster

Fecundity and fertility of Drosophila females were studied after extirpation of one or two spermathecae. When extirpated females were mated only once, egg deposition was slightly accelerated but total egg production, during twelve days, was the same as in virgin operated females. Egg hatchability was high during two days but decreased more rapidly than in normal or sham-operated femalesWhen males were permanently kept with females, egg production and egg hatchability of operated females remained at a high level during the experiment. In that case, females could copulate frequently and the increase in egg production is interpreted as a consequence of paragonial fluid stimulationThe most significant rôle of spermathecae seems therefore to assume the transmission of the sperm stimulus to the brain; they probably also improve the survival capacities of sperm.     

Proposition méthodologique pour une étude des esthétiques du Mésolithique : une analyse sociologique-anthropologique de la fin du Tardiglaciaire et durant le Postglaciaire en Europe occidentale

Do the decorated productions cover esthetics, i.e. the whole of the symbolic systems of a culture of hunters-gatherers? How to leave this glance with the aesthetic requirements that we other Westerners, pose on all things… and to exceed the debate of the artistic expressions thought from the aesthetic point of view, like “works of art” objects and “stylistics” objects? It is out of question “to make a fetish” of the productions decorated “works of art” while placing them at the starting point with our reflexion, (Studying them from a functional, technological, typological, art for art, meaningful point of view…) but to associate another of dimensions of the aesthetic experiment, i.e., the context of the decorated productions.     

Astarte (Digitariopsis) grueti n. sp.et Astarte (Digitariopsis) excurrens lardeuxi n. subsp., bivalves endemiques du Redonien (Pliocene de l'Ouest de la France)

Two new bivalvia (Astartidae) are described. Astarte (Digitariopsis) grueti n. sp. is present in both the Earlyand Late Redonian localities; it confirms the hypothesis of a unique Redonian transgression. Astarte (Digitariopsis) excurrens lardeuxi n. subsp. is a form restricted to the inner part of the Ligerian gulf, where the endemism is more pronounced.     

Glossomyophorus costatus nov. gen. nov. sp., Rudiste (Caprotinidae) nouveau de l'Aptien du domaine méditerranéen central et oriental

A new caprotinid rudist, Glossomyophorus costatus nov. gen. nov. sp. is described and figured from the Lower Cretaceous of Saudi Arabia, Bosnia (Yugoslavia) and southern Italy. Its costulate shell has a straight, tubular (attached) right valve, with a single, central tooth, and an openly enrolled, elongate left valve, with two subequal teeth. It differs from other caprotinids in possessing an erect, tongue-shaped posterior myophore in the left valve, the muscle scar of which directly flanks the body cavity, with no intervening accessory cavity joined to the central tooth socket. This scar faces onto the posterior wall of a laminar posterior myophore in the right valve. A single accessory cavity in each valve separates the posterior myophore from the shell wall. That in the right valve is similar in size to the teeth sockets, such that sections across the valve have a distinctive array of three more or less equal sockets. Evolutionary affinities with Monopleura or with Caprotina are equally possible. At present the genus is only known from the Lower Aptian of the Central and Eastern mediterranean Subprovinces and thus might serve as a valuable biostratigraphic and palaeobiogeographic marker.     

Analyse pollinique des dépôts lacustresdu Pléistocène inférieur de Banyoles (Bañolas,site de la Bòbila Ordis - Espagne): un élément nouveau dans la reconstitution de l'histoire paléoclimatique des régions méditerranéennes d'Europe occidentale

Clays from Bòbila Ordis near Banyoles have yielded a rich pollen flora. Three pollen zones are recognizable: the lower and the middle parts are dominated by components of a deciduous forest (with numerous exotic taxa); in the upper part, Pinus pollen and NAP (especially Compositae) are in a majority with an increase of mediterranean taxa towards the top. This floristic evolution may be connected with a climatic change characterized by a decrease in humidity which is itself linked to a world cooling. We suggest a possible relation with the pollen flora published by H. Elhai. The pollen diagram of Bòbila Ordis is the second so far established from Lower Pleistocene deposits in the Mediterranean countries of Western Europe; chronologically it follows the Bernasso (Languedoc) pollen diagram and confirms the latter results.     

Mise en évidence d'une corrélation entre la fréquence de variations somatiques sur feuilles et l'état physiologique d'un mutant chlorophyllien monogénique chez Nicotina tabacum var. samsun

After treatment with ethyl methanesulphonate (EMS), a chlorophyll mutant of Nicotiana tabacum var. Samsun has been obtained in M₁. Spontaneous somatic variations are observed as isolated areas in the pallisade cells, both on heterozygous and on homozygous plants for the semi-dominant tl gene. These variations appear either as single (green or clear), or as twin (green and clear) areas. This paper reports on the distribution of green somatic variations only, on the basis of the foliar level. The observations have been carried out on a clone homozygous for the tl gene.A highly significant correlation is evidenced between the frequency of somatic variations per leaf and/or per million of cells on the one hand and the physiological stage of the plant on the other. A consistent decrease in the number of variation, after a certain foliar level, is correlated to the transition of the shoot apex from the vegetative to the flowering stage. Modifications of the intracellular conditions caused by this transition could prevent the event responsible for the occurrence of somatic variations. It is also suggested that this event can only take place at a given stage of cell differentiation.     

Mutations et altérations dans la transmission des informations génétiques chez la drosophile par injection d'extraits de chrysalides diapausantes (pieris brassicae) traitées par des ptérines II. Variations dans l'expression des gènes par addition d'hormones de croissance au traitement

Injection into Drosophila larvae of extracts of Pierides and mutants of Drosophila treated by reduced folic acid and pterins always produce juvenilising effects. The hypothesis is therefore suggested that juvenile hormone is released either in the chrysalids or in the injected Drosophila larvae. The addition of juvenile hormone to the injection mixture leads to the killing of pupae and imaginal discs hypertrophied by interstitial liquid or undifferentiated cells in F₂ progeny, which supports the above hypothesis. Addition of cyclic AMP gives the same results but the lethal pupae occur at a slightly later stage; imaginal discs are partially developed, leading to imperfectly developed limbs.     

Ostéologie de Clupavus maroccanus(Crétacé supérieur du Maroc) et considérations sur la position systématique et les relations des Clupavidae au sein de l'ordre des Clupéiformes sensu stricto (Pisces,Teleostei)

Osteology proves definitively that Clupavusmaroccanus is a typical Cluepoid (lateroparietal skull, ethmoidean and fronto-occipital fontanels, recessus lateralis, latero-sagittal fronto-parietal crest, clupeid ural complex, etc…). Clupavus represents a particular non-serrated family, the Clupavidae, different from the Dussumieriidae and the Congothrissidae, the two other primitive non-serrated Clupeoid families. Nor is Clupavus the ancestor of these two families. The systematic position and the relationships of the Clupavidae within the order Clupeiformes sensu stricto are discussed.