Etude comparee des lipides et de la fixation passive du calcium dans les racines et les fractions subcellulaires du Lupinus luteus et de la Vicia faba

In both lupin and broad bean, the root lipids contain paraffins, triglycerides, diglycerides, free fatty acids and polar lipids (phospholipids and galactolipids). The polar lipids and the triglycerides are the more abundant classes. The root galactolipids are mono- and di-galactosyldiglycerides; two steryl glycosides are also present. The phospholipids in both species are: phosphatidylinositol, phosphatidylcholine, phosphatidylglycerol, phosphatidylserine, phosphatidylethanolamine, diphosphatidylglycerol and phosphatidic acid. This last phospholipid represents 8·3% of total lipid phosphorus in Lupinus against 2·3% in Vicia. The other acidic phospholipids represent 30·4% in Lupinus against 20·9% in Vicia. The lipids of Lupinus are rich in linolenic acid whereas those found in Vicia are richer in linoleic acid. The various subcellular fractions prepared from the roots of both species have an homogeneous lipid composition, reflecting exactly that of entire cells. The calcium passive fixation capacity in microsomes and mitochondria of Lupinus roots is more important than that in the same organelles of Vicia faba roots. Thus a relationship is suggested between the amount of phospholipids in membranes and the passive fixation of calcium.     

Activites proteolytiques et anti-trypsine des graines de Vigna unguiculata: Repartition et interaction

Data are given on distribution of caseolytic, BAPA-asic and anti-trypsin activities in albumins and globulins from embryos and cotyledons of Vigna seeds. Embryos are found to be richer in proteolytic enzymes than cotyledons. Trapping of anti-trypsin inhibitors solely enhances the albumin's caseolytic activities. Globulins do not show any BAPA-asic activity. The globulinic anti-trypsin inhibitors are similar on polyacrylamid gels (four fractions) whether the cotyledons or axes are used. The albuminic ones show one fraction more.     

Les α-galactosides du saccharose au cours de la germination des graines de betteraves sucrières et fourragères

During the first three hours of beet seed germination, sucrose α-galactosides briefly appear while sucrose and UDPGal contents decrease. The ¹⁴C-sucrose penetration into 12-hour-old embryos is followed by a partial eclipse of this compound and its replacement by sucrose α-galactosides. These two processes are more important in sugar than in forage beet. The significance of these results in sugar metabolism is discussed.     

Un gradient metabolique: Rapport scopolamine/hyoscyamine dans les feuilles du Duboisia myoporoides en fonction de leur niveau d'insertion et du stade de croissance

Hyoscine and hyoscyamine are the main alkaloids in the Australian plant Duboisia myoporoides. The ratio of hyoscine/hyoscyamine depends both on the developmental stage of the plant and on the position of the leaves on the stem; this ratio is considered as a ‘metabolic gradient’. It is a permanent metabolic marker of a given physiological state.     

Influence de la température sur la biosynthèse des acides gras de deux champignons filamenteux, Aspergillus ochraceus et Mucor mucedo

The two moulds, Mucor mucedo and Aspergillus ochraceus, grow very rapidly at 22°; when transferred to 12°, Mucor shows a regular growth and sporulation while Aspergillus development is almost entirely inhibited. ¹⁴C Acetate was supplied to both fungi at 12° and 22°. In both, the total radioactivity of saturated fatty acids was less important at the lowest temperature. In contrast, C 18:1 radioactivity rose in Mucor while it was C 18:2 radioactivity which rose in Aspergillus at the lowest temperature. There was an increase in phosphatidylethanolamine (PE) and phosphatidylcholine (PC) radioactivities in Mucor while the phosphatidylserine (PS) radioactivity decreased at low temperature. By contrast, when Aspergillus was placed in the same cultural conditions, PE and PC radioactivities decreased while PS radioactivity increased. Based on these results, a tentative explanation of the improved cold-resistance of M. mucedo is presented.     

Les genres Costa et Paleocosta (Ostracodes) du paléogène aquitain: Les structures de populations,témoins des paléoenvironnements. Description de Paleocosta aquitanica nov. sp.

Costa tricostata (Reuss) and Paleocosta aquitanicanov. sp. are polymorph species of the Paleogene Aquitaine. In this study, their constituent forms are both described and illustrated. These are particularly ornamented and show Mesogene affinites; their geographical distribution area is limited within the Aquitaine Basin and Bay of Biscaye.In bathyal environments, the spatial distribution of the Costa, reveals three domains characterized by an increase of faunal density and polymorphism and a morpho- functional adaptation through the strengthening of the shell architecture. We attribute these changes to the effects of an adaptative strategy of the populations within an environment of increasing dynamic activity either near drainage channels and/or accumulation zones of terrigenous material continentally-derived, or within highly intensive upwelling zones.In less shallow environments and/or more close tooceanic influences, the Costa and Paleocosta populations flourish but lose their polymorphism. They announce the ecologic limit of the species.     

Composition chimique de la paroi d'une levure du genre Torulopsis apres culture sur methanol et ethanol

The nature of the carbon source, methanol or ethanol, influences the cell wall composition of the same strain of yeast. Chemical treatment of the cell walls with ethylenediamine indicates that the parietal architecture varies. The analysis of amino acids, sugars and hexosamines reveals quantitative differences with a modification of the elaboration of the polymers. The methanol source favours the synthesis of chitin and mannan polymers, while the ethanol source favours the elaboration of glucan and glucomannan polymers. The chitin percentage rises in a ratio from 1 to 5 and simultaneously the protein percentage rises from 1 to 1.7; consequently the culture on methanol favours the formation of nitrogen compounds.     

Cinetique d'action de l'acide 2-chloro ethylphosphonique sur les polyribosomes du latex d'Hevea brasiliensis

Effects of 2-chloroethylphosphonic acid on the latex of Hevea brasiliensis were studied during 7 days after its application on the tapping panel of the tree. Ribosome polymerisation shows a dramatic rise within 12 hr after treatment. This shift is overcome at first without rRNA synthesis. Increase of latex production and latex pH exhibit similar features and start 24 hr after application of the, stimulant. After 4 days, rRNA concentration and the stability of the lutoïds (microvacuoles with lysosomal characteristics) change significantly.     

Variabilité et disjonction évolutive des caractèresdans les populations de Micraster (Echinoidea,spatangoida) du Crétacé supérieur de Picardie

Morphological variation in Turonian and Coniacian Micraster (Irregular Echinoids) from Picardy is analysed in samples from 4 beds stratigraphically superimposed in the chalk cliff and numbered C2, C3, C4 and C5. The statistical study is made of 23 characters (12 quantitative and 11 qualitative).In first part, uni- and multivariate analysises, complementedby observations of populations, have enabled us to recognize M. leskei (Des Moulins) in the two lower beds and M. decipiens (Bayle) in the upper ones.The growth of M. leskei is analysed in the second part. The biometrical study (bi- and multivariate analysises) of growth processes of the C2-bed urchins (which are small) and of the C3- bed urchins (which are sometimes much bigger) shows the homology of their ontogeny and confirms the name «large M. leskei given by R.B. Stokes for the C3 urchins. The genetic or ecological origin of that variation is discussed.In the third part, the analysis (multivariate) has enabled to understand the considerable variability of M. decipiens. This species contains several morphological types: trapezoidal or heart-shaped urchins, and conical- shaped urchins. The study shows that «gibbous forms are simple variants and that the two first forms may be considered as morphs of the same species. It is possible that these forms are separate species.     

Croissance et mortalité chez Pecten (Gigantopecten) ligerianus (D. & D.) (Pectinidae,Bivalvia) du Miocène moyen du Bassin de la Loire (France): Interprétation paléobiologique

Data provided by living big Pectinids biology allow an interpretation of height frequency distribution for a sample of Pecten (Gigantopecten) ligerianus (D. & D., 1906) from the Miocene “faluns de la Loire.Polymodality is thought originated by interactionof spat recruitment, growth-rate and death-rate.Comparison with a sample of another pectinid from the same formation, Chlamys (Aequipecten) radians (Nyst), catches the eye on mistakes in interpreting size-frequency distributions without taking in account paleoecological and paleobiological conditions proper to both species.     

Organisation de la phase minérale chez Vaceletia crypta (Vacelet)Démosponge,Sphinctozoaire actuelle. Comparaison avec des formes aragonitiques du Trias de Turquie

The fundamental microstructural and ultrastructuralcaracteristics of a non fibrous carbonate tissue has been revealed by the study of the only living Sphinctozoa: Vaceletia crypta (Vacelet), Demospongia.These observations yield important data for interpretation of homogeneous carbonate structure in the skeleton of some fossil sponges. Effectively, we notice that two triassic forms, morphologically very different (Sphinctozoa and Inozoa) show remarkable microstructural analogies with Vaceletia crypta. These considerations should not be leaved out to establish an only classification of Sponges, joining both living and fossil forms.Moreover, the elementary skeletal constituants ofthe two forms show dimensions which indicate a growth in size in comparison with the living species. This increase has probably a diagenetic origin (adjunction of aragonite). So it appears that the present aspect of the mineral components cannot result from a reduction in size (micritization), as has been sometimes asserted.     

Le genre Nucleolites (Echinoidea, Cassiduloidea) du Bajocien à l'Oxfordien dans le Bassin de Paris : apport des données architecturales à la systématique et à la phylogénie

The classification of the Paris basin Bajocian-Oxfordian species of the genus Nucleolites is revised. A classic point of view, until now used by authors and mainly based on the general morphology of the test, is first developed. Then, this last is modified with new architectural data, which refer to the extraxial-axial theory concerning the structure of the apical system as well as the presence of supplementary and catenal plates. These architectural data are first used facing the general morphology of the test. Such approach leads to a new point of view for the classification of the species of the genus Nucleolites. The systematics is particularly significantly simplified. The deduced and proposed phylogenetic hypothesis shows that the genus Nucleolites is composed of two parallel lineages as soon as the beginning of the genus in the Bajocian: a group with a so-called “primitive” architecture, and a group with an “advanced” one. On and after the Late Callovian, the species with a primitive organisation give birth to advanced species, which continue in younger time. In this way, the genus Nucleolites may be paraphyletic since the Late Callovian onward.     

Le Middle Stone Age de la grotte du Porc-Épic (Dire Dawa, Éthiopie) : gestion des matières premières et comportements techniques

With the emergence of Modern Humans in Africa a new post-Acheulean culture seems to take form: the Middle Stone Age. Although the geo-chronological limits of this period remain unclear, it may however be characterised by behavioural modifications, in particular an important change in the relationship between humans and their environment. Theses changes may partially result from the diversification of stone-tool production techniques, as well as socio-economical conditions. Sites dating of this period show that flake types are more abundant and result from exploitation methods that become gradually more sophisticated from about 300ka.In this context, study of the lithic assemblage from Porc-Epic Cave in Ethiopia contributes to the knowledge about operative methods used during the Middle Stone Age. The combined production of flakes, blades, bladelets and points using various methods, a differential economy towards raw materials and the diversity of tool types produced, underline the large extent of technological variability that the Porc-Epic tool-makers were capable of. We may conclude that, in spite of certain differences concerning raw material acquisition, a chronological homogeneity exists in the production modes and their variability. This apparent homogeneity throughout the stratigraphical sequence underlines the difficulty of attributing a cultural characteristic to stone assemblages of this period.