Etude de la reponse à un stress hydrique de quelques varietés de riz pluvial et de riz irrigué

Résumé La transpiration de plants de riz cultivés sur sol en chambre de culture, est suivie en continu pendant une séquence déssèchement-irrigation. Les cycles jouraliers de transpiration sont présentés avant et pendant le stress hydrique. Quatre variétés montrent une augmentation de la transpiration nocturne qui disparait lors du stress hydrique. Il apparait que la régulation stomatique est indépendante du potentiel hydrique du sol jusqu'à une valeur seuil au-delà de laquelle la baisse de transpiration est proportionnelle à la baisse du potentiel hydrique. Cette valuer seuil est plus basse pour les variétés de type irrigué.

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Water stress response for some cultivars of upland- and lowland riceI. Effects on transpiration

Summary The transpiration of rice seedlings grown on soil in a growth chamber was observed during a soil drying/rewetting sequence. The diurnal cycles of transpiration are shown before and during the water stress period. Four cultivars showed an increase of transpiration during the night. This increase disappeared during the water stress period. The stomatal regulation appeared not to depend on the soil water potential until a certain value. Below this soil-water threshold, the decrease of transpiration was proportion to the decrease of water potential. This threshold value is lower for the rain-fed cultivars than for the irrigated cultivars.

     

Influence de la congélation sur le taux de fragmentation de l’ADN des spermes normaux à sévèrement altérés

Ejaculated sperm cryopreservation can be proposed in the course of anART procedure, particularly in the case of severe oligozoospermia likely to deteriorate. The aim of this study was to evaluate the influence of the freezing-thawing process on sperm DNA fragmentation (analysed by the TUNEL technique). The first step of this work consisted of adapting the TUNEL technique to perform this analysis on very poor quality sperm. A study was then performed on 72 patients divided into 4 groups according to their spermatic characteristics: group 1 [n=20] (“normal” parameters according to WHO), group 2 [n=24] (normal sperm count associated with asthenospermia and/or teratospermia), group 3 [n=16] (total sperm count between 5 and 20 M) and group 4 [n=12] (total sperm count below 5 M). Spermatic parameters and DNA fragmentation (performed by TUNEL in situ technique, 400 spermatozoa read per slide) were evaluated on raw semen - for all patients -, raw migrated sperm - for patients of group 1 and 2 -, migrated frozen-thawed sperm - for all patients-. A TUNEL technique adapted to oligospermic samples was developed, manipulating spermatozoa directly on the slide rather than in suspension, to limit spermatic sample loss. After the whole migration-freezing-thawing process, the mean DNA fragmentation rate decreased for patients in group 1 (2.9 vs 5.1%, p<0.0001) whereas this rate increased for patients in groups 2 (10.5 vs 6.8%, p<0.0001), 3 (10.7 vs 7.6%, p<0.05) and 4 (15.2 vs 8.7%, p<0.005). DNA fragmentation rates from thawed samples were also correlated with initial spermatic parameters. At the intermediary step, migration decreased DNA fragmentation rate in comparison with raw semen rate in both groups (1.9 vs 4.7% [p<0.05] in group 1; 2.5 vs 5.4% [p<0.05] in group 2). DNA fragmentation rate decreases after migration and then increases after freezing-thawing so that this rate is lower than the raw semen rate for “normal“ sperms and higher than the raw semen rate for altered sperms. Nevertheless, this DNA damage induced by cryopreservation on altered sperms remains moderate. Sperm “resistance” to cryopreservation also appears to depend on spermatic parameters. Cryopreservation may positively select spermatozoa, accelerating elimination of senescent spermatozoa by necrosis, so that early apoptotic spermatozoa from fresh ejaculate are not found in thawed samples. These results, that need to be completed by a study on a larger sample of oligospermic patients, encourage us to continue cryopreserving severely altered sperms.     

Organisation spatiale des chloroplastes chezEuglena à l'aide de coupes sériées semi-fines

Summary Euglena, gracilis chloroplasts and mitochondria can be seen as a network. This diverticulated structure of the plastidome is only observed in non-dividing cells, during the cell cycle or during the stationnary phase of growth. We have used successions of serial sectioning (0.5 m thick) to reconstitute chloroplast network in three dimensional model.     

Phylogénie de champignons responsables des charbons des végétaux à partir de l'analyse des séquences ITS

Phylogenetic relationships among fungi belonging to the family of Ustilaginaceae (genera Microbotryum, Sphacelotheca, Ustilago, Sporisorium) are inferred from a parsimony analysis using the ITS sequences of nuclear ribosomal genes. The introduction in the phylogeny of sequences from species of Suillus, Puccinia and Taphrina as outgroup shows the polyphyletism of this family. These results support the division of this taxon into two groups: Ustilaginaceae s. str. formed only by the pathogens of Poaceae, and Microbotryaceae constituted by the pathogens of Dicotyledons. Furthermore, we proposed to extend the host plant spectrum of Ustilaginaceae s. str. to all the Monocotyledons. Several discriminating characteristics are listed to support this distinction.     

Sexualisation de la gonade deViviparus viviparus L. (mollusque gastéropode prosobranche à sexes séparés)

Résumé La sexualisation de la gonade chezViviparus viviparus se manifeste d'abord au niveau morphologique: tandis que l'ovaire s'organise en un tubule très peu ramifié, à large lumière, le testicule compact bourgeonne de nombreuses excroissances. Dans l'ovaire les cellules non germinales, futures cellules folliculeuses, se mettent en place autour des cellules germinales et les processus de la préméiose débutent précocement. Au contraire plusieurs étapes se succèdent au cours de la morphogenèse de la gonade mâle: après une phase d'intense multiplication cellulaire, accompagnée de la ramification du testicule, la lumière se creuse par dégénérescence des cellules centrales. Contre la lame basale, les cellules non germinales évoluent en cellules nourricières tandis que se différencient les spermatogonies primaires. La différenciation des premiers gamètes mâles est tardive.     

Hommage à rené delépine à l'occasion de son départ à la retraite

A tribute to René Delépine on the occasion of his retirement. The career of René Delépine is reviewed on the occasion of his retirement. When he was a student, a meeting with Jean Feldmann led to a lifelong inclination towards phycology. Eventually appointed to the position of assistant professor at the University of Paris-VI (University Pierre-et-Marie-Curie), René Delépine worked and published primarily on the taxonomy of antarctic and subantarctic marine algae but he was also interested in seaweed aquaculture and utilizations. After organizing the national colloque ValVA (Valorisation des végétaux aquatiques), he became increasingly involved in the commercial application of seaweeds. His main activity, however, remained university teaching for which he was always enthusiastic, especially for teaching in the field and on the subject of the utilizations of algae. A list of his publications is given at the end of this article.     

Caractérisation des peuplements de macroinvertébrés benthiques à l’aide de la carte auto-organisatrice (SOM)

Macrobenthic organisms are much used nowadays as bio-indicators for their ability to reflect different disturbances of aquatic ecosystems. However, they have never been used to assess the ecological status of the lagoons of Benin. The current study aims at revealing the ecological state of the lagoon of Porto-Novo through the study of changes in the settlement of benthic organisms collected in this lagoon. The sampling was carried out from July 2007 to June 2009 on a frequency of four seasons of collection per year. The self-organizing map (SOM) of Kohonen has been used for various patterns of distribution of collected organisms. A discriminant analysis (AFD) has allowed the identification of the parameters that govern the patterns observed in this environment. Four groups of macrobenthic communities emerged that were well predicted (75%). The distribution of benthic macro invertebrates of this lagoon is therefore zonal, seasonal and discriminated by variables of mineralization and sediment grain size. The difference in taxonomic richness corresponds to environmental conditions of stations appearing more or less stable and highlighting a gradient of the stress on organisms. Places with unstable conditions are affected by human activities due to their proximity to homes that are enriched in organic matter. These places are full of polluted-tolerant species such as the Gastropods Potamididae, Cirratulidae Polychaetes, Diptera Chironomidae and Oligochaeta. The macrobenthic fauna, which is well differentiated in the groups, is then subjected to human disturbance.     

Analyse des courbes de survie clonale obtenues chez des Chlorelles aprés irradiation gamma à divers débits de doses

Résumé Les courbes de survie sont obtenues par irradiation gamma, fractionnée ou non, à débit de dose élevé ou faible. Elles portent sur des Chlorelles à l'état quiescent par rapport au cycle cellulaire (cellules en G₀). Elles s'expliquent en envisageant trois catégories de lésions par irradiation: les lésions létales d'emblée, les lésions sublétales non restaurables et les lésions sublétales restaurables.

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Analysis of clonal survival curves obtained on -irradiated Chlorella cells at several dose rates

Summary The survival curves have been obtained after split or unsplit doses at high or low dose-rate. The living material wasChlorella cells in G₀ stage (non-dividing cells). It is possible to explain these curves by the effects of three types of damage: directly lethal damage, repairable sublethal damage and non-repairable sublethal damage.

     

Activité cytokinine de dérivés acylés,alkylés,acyl-alkylés de l'adénine et d'isost`eres azotés de la γ,γ-diméthylallyladénine

The cytokinin activities of various 6-acylaminopurines, 6-alkylaminopurines, 6-acylamino-9-benzyl-purines as well as a series of isosteric-nitrogen derivatives of N⁶-(γ, γ-dimethylallyl)adenine (I⁶Ade) have been tested using the tobacco pith and the pea bud bioassays. The interactions between active, slightly active and inactive compounds have been studied with the last assay. Acylation decreases the biological activity; e.g., N⁶-benzoyl and N⁶-furoyladenines are less active than Na⁶-benzyladenine and kinetin. Substitution at the 9-position reduces (tobacco-pith assay) or suppresses (pea-bud assay) the phytohormonal activity of otherwise active 6-acylaminopurines. In isosteric derivatives, maximum activity occurs when the side chain has the same length as in 1⁶Ade. After the analysis of interactions between more or less active compounds, it is suggested that the differences in cytokinin activity could be related to unequal affinities for a hypothetical receptor site.     

Les aspects du précipité argentique observé après application de la méthode de v. Kossa-Baraer à des ceufs de souris fixés et incubés dans l'ATP (avec un amendement de la méthode argentique)

Résumé Au cours de recherches relatives aux effets d'une incubation des ufs de Mammifères en présence d'ATP, la méthode argentique de v.Kossa-Barger, appliquée à des ufs de Souris fixés et traitésin toto, a fait apparaître dans de nombreux cas des précipités argentiques d'aspect astéroïde qui ont attiré l'attention.Pour en dégager la signification, des expériences ont été instituées de manière à faire varier: (1) la quantité de phosphate calcique hydraté qui précipite lorsque l'enzyme a libéré les groupes phosphate de l'ATP ajouté comme substrat; (2) la concentration du nitrate d'argent utilisé pour transformer ce sel en phosphate d'argent; (3) la durée de l'irradiation par rayons ultra-violets employés pour dissocier ce composé et obtenir le précipité final d'argent métallique. La structure microscopique des précipités de phosphate calcique hydraté puis de phosphate argentique a également été examinée.Il a été reconnu que les images astéroïdes sont simplement la modalité la plus structurée que peut prendre le précipité argentique. Les aspects de celui-ci dépendent: beaucoup de l'abondance des groupes phosphate libérés; en quelque mesure, de la concentration du NO₃Ag utilisé; davantage, de la durée de l'irradiation appliquée.La discontinuité observée à l'état final de la réaction résulte de l'hétérogénéité du précipité primaire, qui est cependant continu. Sa transformation en grumeaux séparés ou en groupes astéroïdes se produit lors de sa conversion en sel d'argent. L'irradiation peut développer les structures astéroïdes par un phénomène de reerutement et d'association.Pour des valeurs optimales des trois facteurs en jeu (ATP, NO₃Ag et U.V.), les précipités astéroïdes révèlent les régions de l'uf où la libération des phosphates

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Zusammenfassung Wenn Säugetiereier (Maus, Ratte) mit Formaldehyd fixiert, gewaschen und mit ATP und Ca⁺⁺ (ph 8,6) inkubiert werden, entsteht ein Niederschlag von Ca₉H₂(PO₄)₆(OH)₂ (=TCPH), den man mit der v. Kossa-Barger-Silbermethode darzustellen versuchen kann. Hierzu werden die Eier in eine 0,5%ige AnNO₃-Lösung übertragen und dort UV-Strahlen ausgesetzt. Unter bestimmten Umständen nimmt der entstandene Silberniederschlag eine komplexe, oft sternförmige (asteroide) Struktur an.Experimentell werden die aufeinanderfolgenden Stufen dieser Technik analysiert. Auf diese Weise konnten die verschiedenartigen Silberniederschläge erklärt werden. Es wurde gezeigt, daß die asteroiden Niederschläge, die man gelegentlich im Cytoplasma der Eizellen findet, nicht einer Enzymlokalisation entsprechen. Jedoch bedeutet es, daß in dem betroffenen Ei oder einem Eiteil eine bedeutende Menge von Phosphat-Gruppen freigesetzt wurden.Diese Untersuchung ergab, daß es besser ist, statt der gewöhnlichen wäßrigen Silbernitratlösung (pH 5,3) eine durch NH₃-Zusatz alkalisierte Lösung (pH 8,3) zu verwenden, nachdem der AgOH-Niederschlag abfiltriert wurde. Diese leichte Abänderung in der Zusammensetzung der Silbernitratlösung verbessert das Resultat der Reaktion erheblich. Die komplexen Niederschläge erscheinen nicht und die Zuverlässigkeit der Reaktion wird deutlich gesteigert.

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Avec 14 Figures dans le Texte

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Travail réalisé avec l'appui du Fonds National de la Recherche Scientifique et du Centre National pour l'étude de la Croissance normale et pathologique.     

Face à une suspicion de cancer ou de récidive de cancer : pratiques,communication et difficultés des médecins nucléaires français

Nuclear imaging techniques have been occupying an increasingly large place in the study of potentially cancerous morphological abnormalities. A National French survey was conducted among members of the French Society of Nuclear Medicine (Société française de médecine nucléaire) to study the usual practices of nuclear medicine physicians regarding information and communication during the “pre-announcement” stage of a cancer diagnosis. Sixty-six doctors (with an average of 44.7 years of age and 16.3 years of experience) working in mainland France responded to the online survey between November 2013 and February 2014. Most physicians said that they were uncomfortable in this kind of situation. Half of the doctors interviewed faced that situation at least 5 times a month. Communication habits were varied: 20% of them adopted a systematic approach (chose ‘always’ or ‘never’ to communicate information regardless of the patients’ demands) and 80% adapted their approach to the situations and to the patients (communication ‘on case by case basis’ and ‘upon request’). The survey also showed that professionals have contrasting views on the relevance, interest and risks of informing patients about the results of the tests in this kind of situation. Our study shows that it is necessary to discuss the position of nuclear medicine physicians in the pre-announcement procedure set out in the French Cancer Plan so as to reduce the challenges facing them while at the same time organizing and defining their roles.     

Composés bromés de Rytiphlea tinctoria (Rhodophyceae)

Four aromatic bromo compounds have been isolated from the ethanolic extract of Rytiphlea tinctoria after treatment with diazomethane: 2,4-dibromo-1,3,5-trimethoxy-benzene,5,6,3′,5′-tetrabromo-3,4,2′,4′,6′-pentamethoxydiphenylmethane, 5,6-dibromo-3,4-dimethoxy-benzyl alcohol and its ethyl ether. In addition to sterols, amino acids, this extract also contains quinonoid bromo-pigments which could play a rôle in photosensitisation of chlorophylls, a rôle normally taken by the phycobilins, in other Rhodophyceae.     

Étude de deux cent-cinquante souches de bacilles hétérolactiques isolés de vins

Résumé Les auteurs ont isolé plus de 700 souches de bactéries lactiques à partir de raisins, de moûts, de vins de diverses origines et à différents stades de conservation. Ils étudient ici 253 souches de bacilles hétérofermentaires, dans le but d'établir une classification simple et un catalogue permettant un repérage facile des souches.Il est commode de classer les souches d'après la fermentation des pentoses, en raison de la netteté de ces tests, alors que parfois ceux appliqués à d'autres sucres ont des caractères moins tranchés. On retrouve alors la classification qui avait été déjà donnée par Vaughn, Douglas et Fornachon en 1949.Les bacilles pentoses négatifs (26 souches) forment l'espèce Lactobacillus fructivorans. Ceux qui font fermenter seulement l'arabinose (4 souches) ou seulement le xylose (155 souches) correspondent respectivement à Lactobacillus desidiosus et à Lactobacillus hilgardii. L'espèce Lactobacillus brevis comprend les bacilles pentoses positifs (68 souches).

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A study of two hundred and fifty strains of lactic acid bacteria

Summary The authors have isolated more than 700 strains of lactic acid bacteria found in grapes, musts and wines of various origins and at different states of conservation. They study in this work 253 strains of heterofermentative bacilli in order to work out a classification and a catalogue allowing easy identification of the strains.It is convenient to classify the strains from the fermentation of pentoses, on account of the accuracy of these tests, tests on other sugars having sometimes less specific characters. The results are consistant with the classification already established by Vaughn, Douglas and Fornachon in 1949.Pentose negative bacilli (26 strains) constitute the species Lactobacillus fructivorans. The ones which ferment only arabinose (4 strains) or only xylose (155 strains) correspond to Lactobacillus desidiosus and Lactobacillus hilgardii. The pentose positive strains (68) belong to the species Lactobacillus brevis.

     

Les tumeurs testiculaires à cellules de Leydig: à propos de quatre cas et revue de la littérature

Introduction

Leydig cell tumors of the testis are uncommon, and represent 1 to 3% of all testicular tumors, it’s the most common of sex cord stromal tumors. They can be found in all age groups, but they mainly occur in subjects aged 15 to 50 years (50%), 25% occurring in older men and a little less than 20% in children aged 5 to 9 years. The most common revealing symptom is gynecomastia in adults, whereas in children it is isosexual pseudo-precocious puberty. They pose a problem during diagnosis, nonpalpable tumors, and during the choice of surgical treatment, because it is difficult to make a clear distinction between benign and malignant tumors.

Material and methods

We describe four different presentations of this disease. The parameters studied were: age, revealing symptom, hormonal profile, type of treatment, and mode of evolution.

Results

The average age of our patients was 37.5 years. The first revealing symptom was a unilateral increasing size of purse in two cases, a bilateral increasing size of purse in one case, and gynecomastia in the last one. In all cases testosterone was normal or low, and oestradiol was normal or elevated. Our four patients underwent an orchidectomy, associated with an enucleation of the contralateral testis in only one case. A favorable evolution was observed in every case for a mean follow-up of 15 months.

Conclusion

On the basis of four different clinical observations and the analysis of the literature, the aim of this review is to present the various clinical, biological, radiological, pathological and therapeutic aspects of Leydig cell tumors of the testis.     

Contribution à l'étude de la bryoflore Lorraine

Contribution to the knowledge of the bryophyte flora of Lorraine (France). The bryophyte flora of Lorraine (France), which was not extensively studied during the second half of this century, has been visited again over the last four years. Seligeria acutifolia Lindb. has been collected for the first time in that region. New localities of several rare or poorly known bryophytes are given. A perspective view is proposed as to the future of bryological research in Lorraine.