Isoetine,nouvelle flavone isolee de Isoetes delilei et de Isoetes durieui

A new flavone isolated from Isoetes has been identified as 2′,4′,5,5′,7-pentahydroxy flavone.     

L'excursion dans le Nord et l'Ouest de la France de la société internationale de phytosociologie

Sans résumé     

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.     

Isothiocyanates,thiourees et thiocarbamates isoles de Pentadiplandra brazzeana

The isolation of isothiocyanates, thioureas and thiocarbamates from Pentadiplandra brazzeana is described. The structures of these compounds were established by IR, ¹H-NMR and MS. The thiocarbamates have bactericidal properties.     

Phagocytose et pinocytose par l'ectoderme et l'endoderme de Cerianthus lloydi Gosse

Starved Cerianthus lloydi Gosse were fed experimentally with Crangon muscles ground and impregnated with Bromocresol Green powder. A phagocytosis of the muscular fibres was detected in the cells of the endoderm layer of the sterile septa. In addition, through feeding with chicken blood, a phagocytosis became evident in the endoderm of sterile septa and of tentacles.The use of Ferritin allowed us to prove an uptake in all the endoderm cells of Cerianthus lloydi with an intensity which varies from one tissue to another. Furthermore, there is an unexpected pinocytosis in the ectoderm layer of the peristome, of pharynx, and the labial tentacles.Results obtained with bacteria and labelled amino acids are less conclusive. Perhaps the techniques used were inadequate.     

Les Spatangus du Miocène et du Pliocène de l’Ouest de la France

Numerous fragments of spatangoid echinoids have been discovered in the Pliocene deposits of Challans, in Vendée (western France). In spite of the fragmentary data of the samples, a reconstitution of a complete test could be realized using the different fragments and their symetrization. The general shape of the test, and its architectural and ornemental characters allow establishing the presence of the genus Spatangus in western France during the end of Neogene. It allows to precise the biogeography of the genus Spatangus and of the morphological group S. (S.) purpureus on the Atlantic coast after the Messinian crisis. The Pliocene species is compared to the Miocene Spatangus (Phymapatagus) brittanus, abundant in Anjou, Brittany and Touraine. This older species was refered to the subgenus Phymapatagus according to the presumed lack of primary tubercles on its posterior interambulacrum. The discovery of well-preserved specimens, with primary tubercles on every parts of the test, in the Middle Miocene of Brittany allows to refute this subgeneric distinction and to refer the species brittanus to the subgenus Spatangus (Spatangus). The presence of this subgenus in western France is finally confirmed from Middle Miocene to Pliocene.     

Ultrastructure de l'ectoderme des tentacules labiaux et marginaux de Pachycerianthus fimbriatus McMurrich

In Pachycerianthus fimbriatus McMurrich, collar cells have been found in the ectoderm layer of marginal and labial tentacles. Villi, nematocytes, spirocysts, two types of mucous gland cells, and trypsinogen gland cells have been described. We have failed to discover special apical structures linked with the uptake of ferritin in solution. The rôle of apical villi and collar cells is discussed.     

Ulminium diluviale Unger : historique de la découverte et nouvelle étude

A fossil tree was discovered during the 16th century at Jáchymov (Bohemia). The wood was first named by Unger, in 1842, Ulminium diluviale. But it belongs to the Lauraceae family and Felix, in 1883, named it Laurinoxylon diluviale. The authors give the history and the geological setting of the area and describe the anatomy of the wood. The diagnosis of the genus Laurinoxylon Felix, 1883. is emended as follows: heteroxylous fossil wood with average sized solitary vessels or in radial groups; perforation plates simple and sometimes scalariform; intervascular pits alternate and moderately large; thyloses present. Paratracheal parenchyma. Uni to five seriate rays, slightly heterocellular and less than 1 mm high; ray-vessel pits large often stretched. Libriform or with radial pits fibres. Oil cells or mucilage (idioblasts) present. The diagnosis of the species Laurinoxylon diluviale (Unger) Felix, 1883. is also emended. Heteroxylous fossil wood with distinct growth rings; late wood poorly developed with vessels of diameter distinctly smaller as compared to the early wood and with smaller diameter fibres. Diffuse to semiporous vessels, solitary or in radial groups of two to seven , nine to 16 pores/mm²; tangential diameter 100 to 154 μm in early wood and 44 to 72 μm in late wood; vessel length 300 to 550 μm; perforation plates simple and scalariforme (6–12 bars); intervascular pits alternate, rounded (diameter 7–10 μm) or elliptic (long axes × short axes: 10–15 μm × 7–10 μm); thylosis present. Paratracheal parenchyma in more or less complete rows (1–2 cells wide) around the vessels. Heterocellular rays (1–(3) rows of upright cells), of one to five, more frequently three to four cells wide (80%); two to 36 cells high (60 to 820 μm); six to seven rays per tangential millimetre; vessels-rays pits sometimes large, stretched horizontally to vertically. Fibres of 15 to 25 μm in diameter; cell walls of 2–3 μm thick; pits not seen. Oil cells (idioblasts) at the ray margins; 27–60 μm in tangential diameter; 50–80 μm in radial diameter; 72–140 μm high; density of zero to 18 per transversal square millimetres depending on the observed area.     

Sur l’origine bactérienne et fongique de la pigmentation de l’Ammonitico Rosso (Jurassique, région de Vérone, Italie du nord)

Fourteen sections in the Ammonitico Rosso Veronese (Callovian to Tithonian, Trento altipiano) disclose the presence of diverse facies ranging from pelagic to outer platform. In spite of this diversity, red limestones are present at different levels. Many microfacies are similar to those observed in other Paleozoic and Mesozoic red carbonates with an abundance of hematitic bioconstructions. We therefore postulate that the origin of the pigmentation is similar in all the studied cases and due to the activity of iron-oxidizing bacteria. Nevertheless, 2 notable differences are observed: the presence in the Ammonitico Rosso of manganese and the existence of in situ bacterial-fungal mats in the matrix. These “algal” mats can represent up to 20% of the sediment. Their excellent preservation (absence of packing down or crushing) is due to the slow sedimentation rate of the pelagic sediments or of the hardgrounds.     

Phenylpolyenes d'Aspergillus niger: structure et proprietes de l'asperrubrol

When grown on a synthetic medium containing Zn²⁺ and Cd²⁺ in toxic concentrations and a high concentration of Mg²⁺, the mycelium of Aspergillus niger ATCC 9029 is pigmented yellow. Four pigments have been chromatographically separated. Two are still unknown; the others are asperenone and asperrubrol. Asperrubrol is the methyl ester of a dimethyl 13-phenyl-3-ol-2,4,6,8,10,12-tridecahexaenoic acid. One of the methyl groups is on C₂ and the other is probably at C₈. Asperrubrol has been obtained as the enol of the all trans molecule; ketoe nolisation can be obtained by action of heat or alkalis. When grown on the same medium, 13 of 17 strains of A. niger produced asperrubrol and asperenone.     

Biosynthese des ramifications en C-24 des phytosterols de Physarum polycephalum et d'Ochromonas danica

The side chain C-24 alkylation mechanism of phytosterols of Physarum polycephalum and Ochromonas danica, cultured in a nutrient medium containing methionine-CD₃, has been studied. Depending on species, five or four deuterium atoms were incorporated respectively in C-24 ethyl phytosterols. No relation could be established between the stereochemistry of C-24 and the alkylation mechanism at this position.     

Role des corpora allata et cardiaca sur l'action cardioaccélératrice de la lumière et de la température chez Locusta migratoria

A rise in temperature as well as the passage from dark to light increases the cardiac beat of adult Locusta migratoria. Continuous exposure to light considerably decreases the sensibility to temperature variations. Neither the corpora allata nor the corpora cardiaca have any influence in this case.     

Teneurs en éléments majeurs et traces de spirulines (Arthrospira platensis) originaires de France,du Tchad,du Togo,du Niger,du Mali,du Burkina-Faso et de République centrafricaine

Data on mineral elements in spirulinas being limited, we analyzed macrominerals and trace elements of samples from France and Africa. Spirulinas cultivated in France have a composition in macromineral elements similar to those of the literature. The entire contents of trace elements are low. Unlike marine cyanobacteria, they do not concentrate rare-earth elements. Spirulina harvested in Chad has high levels in macrominerals and trace elements, due to traditional drying and harvesting methods. Rare-earth element levels are attributed to this pollution and not to their concentration in spirulinas, because rare-earth element normalized profiles of spirulina are strictly parallel to those of ouadis mud and very different from those of ouadis water. Despite the sometimes high content of total As, normal water consumption in Chad presents no health problems. Spirulinas grown in Togo, Niger, Mali, Burkina-Faso and Central African Republic have chemical compositions similar to those of Chad spirulinas, but with a lower content of macromineral and trace elements, reflecting a lower mineral pollution. Rare-earth element normalized patterns dismiss an aeolian pollution and the pollution is rather of pedological origin. They show no toxicity problem except spirulinas from Burkina-Faso, whose Pb content is too high. The variability of composition of spirulinas can be largely attributed to the mineral pollution of the samples. Significant levels of rare-earth elements sometimes found in the literature reflect this pollution.