Etude de la fertilité des eaux marines au moyen de tests biologiques effectués avec des cultures d'algues I. Comparaison des méthodes d'estimation

Several methods of growth potential estimation of marine productivity are discussed: (1) simultaneous measurements of nutrient content and organic production, (2) chemical composition of algal cells, (3) bioassay with algal cultures. This last method appears to be the most convenient; it allows to study the role of a nutrient component both when utilized alone and when combined in a pool of nutrients. Several aspects of bioassay technology are discussed: test species, chemical enrichments and growth estimation of test cultures.     

Evolution des activités enzymatiques dans le tractus digestif au cours de la vie larvaire de la sole. Variations des protéinogrammes et des zymogrammes

The activities of digestive enzymes were studied during the course of larval development (from hatching to 30 days) in the sole, Solea solea. No glycosidase activity was present, but alkaline proteolytic activity increased from hatching to day 5, then decreased until day 15. In the acid range, proteolytic activity was relatively stable from the 10th to the 30th day. There were also changes in the number of esterase-like isozymes which increased between day 20 and 30, with minimum activity observed during metamorphosis.     

Etude par Spectroscopie Infrarouge de la Transformation Hélice—Chaine Statistique des Polypeptides. I. Etude Comparée de l'Interaction de la Poly-L-alanine et d'un Amide Modèle avec l'Acide Trifluoroacétique

Infrared spectra of poly-L -alanine in trifluoroacetic acid-chloroform mixtures have been investigated and compared with those of a model amide (N-methylacetamide). The purpose of this work is to determine the nature of peptide-acid specific interactions responsible for the helix-random coil transition of polymer chains. Analysis is made in using amide (A, I, II, III) and acid (νC?O, νOH) vibrations which are specially sensitive to molecular interactions. We examined a model compound to determine the spectral characteristics of the different complexes or species formed between amide and acid. At a low acid concentration, hydrogen-bonded complexes: ? (NH) C?O…?HOOCCF₃ (1) are evidenced but no association between amide NH and acid CO groups (complexes A) is observed. For higher acid concentrations complexes (I) are progressively changed into ions pairs and free ions, which result from amide protonation by acid, according to the exothermic equilibrium (I)?? (NH)COH⁺, ^?OOCCF₃(II). Amidium and carboxylate bands are localized between 1680–1705 cm^?1 and 1620–1625 cm^?1, respectively. If the cation band is always clearly seen, the anion band is only observed for the most acidic solutions. For the polymer, a gradual complexation of type (I) is observed for all acid concentrations. From our results, the assumption of an (A) type interaction seems very unlikely but cannot be excluded. Moreover, proton transfer—similar to that observed with a model amide—is never evidenced since, in particular, the amidium band characteristic of protonation is never seen. In contrast to previous investigations, we conclude that the helix-random coil transition of polypeptides is not due to the protonation of the peptide functions. This transition does suggest a strong interaction by hydrogen bonds between polymer and acid molecules.     

Structure des membranes biologiques: localisation des galactosyldiglycerides dans les chloroplastes au moyen des anticorps specifiques. II. Etude en microscopie electronique a l'aide d'un marquage a la peroxydase

Structures of biological membranes: Localisation of galoctosyldiglycerides in chloroplasts by means of specific antibodiesII. Treatment with peroxidase: electron microscope studyThe results obtained in this study confirm that the outer membrane of the chloroplast envelope contains galactosyldiglycerides and that these molecules are uniformly distributed over the membrane surface. The results show that the galactosyldiglyceride molecules that are accessible to antibodies at the level of the thylakoids are distributed over the membrane surface in discrete patches.     

Applications biologiques de la spectroscopie Raman de résonance et de la spectroscopie micro-Raman de résonance

Advantages are given to illustrate the possibilities of resonance Raman spectroscopy in the studies of biological systems.A relation giving the size of porphinato-core of metalloporphyrins from resonance Raman frequency is proposed. It can be applied to heme, even in lived state.By illuminating the sample through a microscope, resonance Raman effect can be collected from 1 (μm)² of sample. Spectra of a vegetal-cell wall (pimento) and of a red corpuscle (hemoglobin) are shown as examples.     

Modification de la fertilité du carpocapse Cydia pomonella à la suite du contact des adultes avec un régulateur ou un inhibiteur de croissance d'insectes

Résumé Des papillons de carpocapse Cydia pomonella L., mâles et femelles séparés, sont soumis au contact des résidus secs du CGA 184'699, un inhibiteur de croissance d'insectes (ICI) et du fenoxycarb, un régulateur de croissance d'insectes (RCI). Ils sont ensuite regroupés dans boîtes non traitées pour l'accouplement et la ponte. La fécondité du carpocapse n'est pratiquement pas affectée par ce conditionnement mais sa fertilité diminue avec l'augmentation de la concentration des produits et avec la durée d'exposition. Avec le CGA 184'699, l'efficacité ovicide induite atteint environ 50% suite à un contact de trois jours avec les résidus d'un traitement à 100 mg/l, alors qu'avec le fenoxycarb elle s'élève à 87% dans les mêmes conditions. Avec le CGA 184'699, seul le contact des femelles avec les résidus provoque cette réduction de fertilité, alors que le fenoxycarb agit sur les deux sexes.

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Summary Codling moth, Cydia pomonella L., males and females were exposed separately to contact with dry residues of CGA 184'699 an insect growth inhibitor (IGI) and fenoxycarb, an insect growth regulator (IGR), The sexes were then grouped together in non treated boxes for mating and egglaying. Fecundity of codling moth was little affected by this treatment but its fertility decreased with increases in the concentration of products and the duration of contact. Induced ovicidal efficacy was about 50% after three days contact with the residues of a 100 mg (a.i.)/l application of CGA 184'699, whereas the same conditions led to about 87% efficacy with fenoxycarb. With CGA 184'699, only contact by females affected egg eclosion whereas fenoxycarb acted on both sexes.

     

Etude par spectroscopie infrarouge de la transformation hélice–chaîne statistique des polypeptides. II. Etude de l'interaction de quelques polypeptides à chaînes latérales polaires avec l'acide trifluoracétique

The various polymer–acid solvation possibilities occuring in the helix–coil transition process of polypeptides with polar side chains were systematically analyzed by infrared spectroscopy. The following samples have been considered: poly-γ-benzyl-L -glutamate (PBLG), alternating poly-γ-benzyl-D ,L -glutamate (PBD-LG), and poly-β-benzyl-L -as-partate (PBLA). The behavior of the amide A, I, II, and νC?O ester absorptions of each polymer dissolved in trifluoroacetic acid–chloroform mixtures was studied in depth. The classical assumptions concerning the interaction between a polypeptide and a proton donor solvent are discussed. This interaction was previously proposed in a theoretical model of helix–coil transition. For PBLG, the spectral characteristics of the cooperative transition are evidenced by the amide bands. These bands also show main chain–acid hydrogen bonding (I) Quantitative analysis of phenomenon (I) was performed in order to localize the “binding sites” of the polymer. In agreement with the theory, only the complexation of peptide units belonging to random coil and terminal helical regions were observed. However, in contrast to the theory in which the association constants KCO and KNH of these residues are generally kept equal, the present results have shown that the main binding site is the carbonyl group (KNH ? 0 or « KCO ). The behavior of the polar side chains of these polypeptides were analyzed during the transition. Similarly to the peptide backbone, they bind the acid by hydrogen bonding (II) Furthermore, this association is more important when the side chains are localized in the coiled regions than in the helical ones. This result suggests, by analogy with the main chain behavior, that the helix–coil transition theory should take into account two more association constants for polar side chains, namely k₁ for the helical regions and k₂ > k₁ for the coiled ones.     

Etude de la globuline des graines de Tournesol (Helianthus annuus L.) accumulation au cours de la maturation et localisation intracellulaire

Protein synthesis and accumulation in growing sunflower (Helianthus annuus L.cv.Airelle) seeds are studied. The salt soluble fraction, globulin, is the main soluble protein component. The earlier stages of seed development (10 days after flowering) are characterized by high M_r polypeptides (74, 58 and 44 kDa). Later stages mainly show nature globulin polypeptides. Thus, protein synthesis in seed occurs at a specific period of seed development which follows a period of fast cell divisions (0–14 days after flowering). Protein bodies are isolated and their protein composition analyzed. Globulin subunits are the main polypeptides of protein bodies soluble fraction. Mature globulin is only stored in protein bodies.      

Synthèse et dégradation des composés glucidiques au sein de la communauté planctonique en zone marine eutrophe

A general study on the relations between “phytoplanktonic excretion” and “heterotrophic assimilation” has been carried out in eutrophic systems, natural or artificial. In the complex systems of these relations, two types of heterotrophic responses were obtained according to prevailing algal species. High heterotrophic potentials in NW African upwelling show the role of microorganisms in the disappearance of freshly excreted organic substances and in the composition of the remaining organic matter.     

Aspects ultrastructuraux et synthèse de la thyroglobouline dans les cultures de thyroides avant et après transplantation chez des rats hypophysectomisés

Two aspects concerning the study of thyroglobulin synthesis and of the ultrastructure of thyroid glands in organotypic cultures have been studied: (1) the chronology of ultrastructural alterations in thyroid cultures leading to the loss of thyroglobulin synthesis; and (2) the role of TSH in the re-establishment of the characteristic features in the cultured cells following transplantation.Alterations of the endoplasmic reticulum start on the very first day of culture. The ribosomes detach themselves from the membranes which then disappear. On the third and fourth day, significant alterations are observed on mitochondria and nuclei. The lysosomes disappear, while the Golgi apparatus is hardly affected.All the above modifications are reversible, since it is possible to re-establish the characteristic features of the endoplasmic reticulum and the synthesis of thyroglobulin after transplantation of the cultured glands into normal animals.The reappearance of phenotypic traits of the thyroid cells can also be obtained after transplantation into hypophysectomized rats. However, the level of thyroglobulin synthesis in these transplants, which is similar to that in the host gland, is lower than in grafts into normal animals.This results shows that TSH is not required for differentiation and for manifestation of the phenotypic traits of the thyroid gland. It seems therefore that the role of TSH is not to stimulate differentiation, but to maintain and regulate the level of specific processes in the already differentiated thyroid cell.     

Etude préliminaire des effets de la mise en eau du Réservoir de LG-2 (Territoire de la Baie James,Québec) sur le seston grossier et le zooplancton des rivières et des lacs inondés

Preliminary Study of the Effects of Impoundment of LG-2 Reservoir (James Bay Territory, Quebec) on the Net Seston and the Zooplankton of Impounded Rivers and Lakes The effects of impoundment on the biomass of net seston and zooplankton in lakes and rivers of Northern Quebec were investigated from 1978 to 1980, before, during and after the completion of LG2 Reservoir on the River La Grande (53° 54′ N, 76° 78′ W). In lotic stations, a 41–77% decrease in net seston was observed due to sedimentation of mineral particles (36–80 mg/m³ in 1978 to 10–21 mg/m³ in 1979). The ratio of organic to total seston increased from an average of 0.18 before the impoundment to 0.65 after. The flooding phase brought about a trophic upsurge; the biomass of the zooplankton increased by one to two orders of magnitude at the various sites; the greatest increases occurred in the central stations near the dam, the smallest in the upper stations near the inflow. In lake stations, no significant difference between years could be detected; the mean zooplankton biomass for all three years ranged from 6.59 mg/m³ to 34.34 mg/m³. Spatial variations between lakes were however significant. Results are compared with those in other natural lakes in Canada and reservoirs in the United States. Comparative examination of phytoplankton biomass before and after impoundment of LG2 Reservoir suggests that bacterioplankton and allochthonous organic material are key elements in the pelagic food chain after impoundment.     

Etude de quelques propriétés de la phosphofructokinase érythrocytaire de l'homme normal

Human erythrocyte phosphofructokinase was purified 150 fold by DEAE cellulose adsorption and ammonium sulfate precipitation.At pH 7,5 the enzyme exhibits allosteric kinetics with respect to ATP, fructose 6 phosphate, and Mg²⁺.ATP at high concentration acted as an inhibitor and ADP, 5′AMP, 3′,5′, AMP, acted as activators. Both effectors seemed to decrease the homotropic interactions beetween the fructose 6 phosphate molecules.The activators increased the affinity of phosphofructokinase for the substrate (F6P), the inhibitor decreased it.These ligands had no effect on the maximum velocity of the reaction except in the case of ADP.Interactions between the substrates and the effector ligands on the enzyme were considered in terms of the Monod - Changeux - Wyman model for allosteric proteins.With GTP and ITP, no inhibition was observed. At saturing concentration of GTP, ATP still inhibited phosphofructokinase.Both 3′5′ AMP and fructose 6 phosphate increased the concentration of ATP required to produce an inhibition of 50 %.Citrate, like ATP, inhibited phosphofructokinase by binding most likely at the same allosteric site. Erythrocyte phosphofructokinase is inhibited by 2–3 DPG.The study of the relation log V max = f (pH) suggested, that the active center contains at least one imidazole and one sulfhydryl group.     

Modifications des propriétés cytophotométriques des ADN et des histones nucléaires au cours de la sénescence des tritons (Triturus vulgaris et Triturus cristatus)

DNA and histones were studied by cytophotometry, in cartilaginous cells from urodele amphibians (Triturus vulgaris and Triturus cristatus) during ageing. With the Feulgen reaction, the DNA colorability decreased and their acid hydrolysis was more difficult. The coloration of the histones linked to DNA in chromatin was also changed. The results are discussed in relation to numerous works on deoxyribonucleoprotein modifications during cell ageing.ADN et histones ont été étudiés par cytophotométrie dans les cellules cartilagineuses d'Amphibiens Urodèles (Triturus vulgaris et Triturus cristatus) au cours du viellissement. Nous avons observé une baisse des affinités tinctoriales des ADN et une augmentation de leur résistance á l'hydrolyse acide pratiquée dans le cadre de la réaction de Feulgen. La colorabilité des histones associées aux ADN dans la chromatine est aussi modifiée. Tous ces résultats sont discutés en liaison avec les nombreux travaux effectués sur les modifications des désoxyribonucléoprotéines au cours du viellissement cellulaire.     

Néandertal et le feu au Paléolithique moyen ancien. Tour d’horizon des traces de son utilisation dans le Nord de la France

This article aims at drawing up balance sheet of remains of fire use by the first Neanderthals of Northern France, during the second part of the Saalian (MIS 8 to 6). This overview reminds us the rarity of fire testimonies during Early Middle Palaeolithic (300–130 ky BP) on the scale of North-Western Europe. For Northern France, only the sites of Biache-Saint-Vaast and Therdonne present remains of combustion. At Biache-Saint-Vaast, it is not less than six levels, which present clues of combustion: burnt flint and faunal remains and sometimes charcoals. At Therdonne, besides burnt numerous flint and some rare faunal remains were brought to light during the excavation of level N3 several rich zones in organic residues and micro-charcoals. All the datas collected concerning the clues of combustion at Biache-Saint-Vaast and Therdonne is compiled, analyzed and interpreted. This approach permits to establish the fire use or its absence in saalian occupations of Neanderthals of Northern France and to discuss modalities of its use, particularly at Therdonne. To conclude, fire status and its implications in first Neanderthals occupations are briefly discussed.     

Traces d’impacts de projectiles sur le gibier : résultats comparés des tirs expérimentaux à l’arc et au propulseur effectués au Cedarc (Treignes, Belgique) en 2003 et 2004

In 2003 and 2004, two series of projectile experiments were organized by P. Cattelain and ourselves at the CEDARC/Musée du Malgré-Tout (Treignes, Belgium). The experiments involved the use of two male ox calves and two female fallow deers as targets for bow and spearthrower shooting. Our main focus was a functional analysis of the antler projectile tips from the Upper Magdalenian layer of the Isturitz cave site (Pyrénées-Atlantiques, France). The study of the impact traces on the bones of the target animals was also included in the project; its results are presented here. The observation of these 127 traces led us to reconsider the nomenclature suggested by P. Morel, and to distinguish between three major traces: notches, punctures and perforations. Correlations appear between the nature of the trace and the shape of the bone (e.g., scapulae strongly associated to perforations), and the bone's mineral content: compared to adult long bones, immature long bones are much more easily perforated by projectile points, which usually remain firmly caught in them. However, our results do not show a clear distinction between the impact traces left by the bow and by the spearthrower.