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.     

Variations de la pression interne au cours de l'émergence et de l'expansion des ailes chez Bombyx mori et Pieris brassicae

During the final stage of development the haemolymph of Lepidoptera does not seem to undergo great variations of pressure. At most, sudden rises of 10 to 15 mm Hg were noted during violent movements or at ecdysis.With an improved and very sensitive apparatus, a pressure eighteen times higher than the pressure measured normally was recorded. This sudden variation of blood pressure corresponds to the erectile stage of the extension of the wings. The study under different conditions has shown the importance of the part played by the abdominal muscles in the pressure of the haemolymph.     

Le site des Vachons : étude de la partie gravettienne de la collection de l’IPH

This article firstly summarizes the process of study of an old collection, which had not been considered since the excavations at the site Les Vachons, started before 1914 and completed around 1939. The studied collection of J. Coiffard, both excavator and inventor of this site, includes four-fifths of the artefacts because, in 1940, he donated approximately one fifth to the Eyzies Museum. For his part, J. Bouyssonie who participated in the excavations for 3 years gave the major part of his own collection to the Archaeological Society of Charentes Angouleme where its condition makes it difficult to analyze. Despite these restrictions, based on statistical comparisons with counts many other sites, I came to the conclusion that the top three layers of Les Vachons are a confirmation of the Gravettian model, developed by B. Bosselin and F. Djindjian through their factor analysis. This model seems much better suited to the stratigraphy of Les Vachons, than all assumptions made by previous analysts in their attempt to bring the industries from the three layers in what remains from the Peyrony model.     

Identification des constituants de l'essence des aiguilles de Pinus pinaster

The chromatographic analysis of the volatile leaf oil of Pinus pinaster Ait. showed 42% of monoterpene hydrocarbons (α-pinene, camphene, β-pinene, myrcene, 3-carene, limonene, cis-ocimene, terpinolene, para-cymene, 35% of sesquiterpene hydrocarbons (cubebene, copaene, caryophyllene, humulene, germacrene D, α- and γ-muurolenes, δ- and γ-cadinenes) and 23% of oxygenated compounds including esters (linalyl, bornyl, geranyl, neryl and farnesyl acetates), alcohols (cis-hexenol, linalool, α-fenchol, trans-pinocarveol, terpinen-4-ol, α-terpineol, dihydrocarveol, guaiol, junenol and α-cadinol), one aldehyde (hexenal) and one ketone (piperitone). Three non terpenoid phenylethyl esters were also identified: phenylethyl isovalerate, methyl-2 burtyate and 3-3 dimethylacrylate. Some alcohols and mainly α-terpineol and linalool seemed to be formed during the steam distillation process, they were absent when the leaf oil was obtained by maceration of small portions of leaves in the usual solvents of terpenes.     

Mise en evidence de l'existence de sensilles chemorecepteurs sur les antennes d'un crustace mysidace cavernicole et de l'intervention de ces sensilles dans la detection d'un extrait de nourriture

The cavernicolous crustacean Antromysis juberthiei showed unexpected behavior when presented with food extract : it avoids the area of odor inflow. This avoidance reaction is reduced by removal of various combinations of antennae and disappears almost with bilateral removal of the first antennae (the aesthetasc-bearing antennules).     

Repartition des flavonols dans l'epaisseur des feuilles de quelques vegetaux vasculaires

The tissue localisation of flavonoids has been studied in leaves of Betula, Corylus, Fagus, Fraxinus, Pisum, Platanus, Quercus, Spinacia and Tilia and scales of onion bulbs. All these species contain flavonols which are, for the most part, located in the upper epidermis of the leaves. In the onion bulb, flavonols are exclusively in the epidermis. The flavonols are glycosylated and dissolved in the vacuoles. The leaves were fractionated by an original technique of abrasion of the frozen material. The physiological significance of such a distribution of flavonoids in the adult leaves or scales is discussed.     

Effets des marées sur la variation circadienne de la capacité photosynthétique du phytoplancton de l'estuaire du saint-laurent

The photosynthetic capacity of phytoplankton was measured at an anchor station in the Middle Estuary of the St Lawrence, over a period of 120 h. Hourly incubations were made in constant light conditions, under three different colour filters of 3, 4 and 23 W · m^?2. Differences in the oscillations of the photosynthetic capacities were observed in relation to the tidal regime. During spring tide, variations in the photosynthetic capacity are circadian, whereas a tidal pattern was also observed during the neap tide period. Differences in the patterns of photosynthetic capacity were probably due to changes in the gradients of physical factors and to the physiological state of phytoplankton relative to these gradients. The circadian rhythms appeared to be endogenous since they were apparent at non-saturating light intensities and since the photosynthetic potential (U_max) changed during the day.     

Polymorphime de l'oleate de sodium anhydre

By careful experiments with a DTA apparatus equipped with a closed sample-holder for operations at elevated temperatures and pressures, it was found that pure sodium oleate shows 8 phases: I crystalline, II and III not well defined, IV and V face centered structures, VI ribbons phase, VII and VIII labile lamellar structures. These results are discussed and compared with the other literature data.     

Contribution à l'étude de la microfaune des récifs messiniens d'Oranie Occidentale (Algérie)

Benthonic Foraminifera and Ostracoda from the reefal Messinian of Western Oranie (Algeria) belong partly to species already known in the mediterranean Tortonian and Pliocene and partly as far as Ostracoda are concerned to new species. These last ones are perhaps in connection with the reef facies they could characterized all around the Mediterranean Sea.     

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.