Etude hydrobiologique des lagunes du nord de la Tunisie

The limnology of three lakes in Tunisia was studied over a period of two years. These lakes differed substantially in the degree of salinity and resistivity. Physical and chemical parameters occurring in the lakes were analysed for a year. The investigation indicated some discussion about the following factors: Temperature, chlorides, potassium, sodium, calcium, carbonates, bicarbonates, dissolved oxygen, nitrats...In an another paper (second part), the author will study the interrelationships between annual variations of algal populations (plankton) and annual variations of these physical and chemical factors.

     

Addition à la faune malacologique du Tyrrhéniende Monastir (Tunisie)

The tyrrhenian malacofauna inventory from Monastir (Tunisia) is enriched by two species of Gastropods and three species of Bivalves, not yet locally reported.     

Les associations des calpionelles du Berriasien et du Valanginien inférieur de la Tunisie septentrionale. Comparaison avec les associations du Rif externe (Maroc)

The study of ten thin sections from outcrops from Lower Cretaceous deposits and several thin sections obtained from three petroleum wells, allow us to better characterize the associations of calpionellid zones and subzones of the Berriasian and Lower Valanginian in northern Tunisia. The B and C zones, respectively, show three and two levels with calpionellid associations corresponding to B1, B2, B3 and C1, C2 subzones. In the D zone, associations of the D1 and D2 subzones were identified. The E zone has been characterized for the first time in Tunisia and in southern-Tethyan margin of North Africa, on the basis of its index specie and associated species.     

Contribution a l'etude des ceintures de vegetation d'une lagune continentale du nord de la tunisie (lac ischkeul)

For all stations, we established a sharing in space and time (according to abondance-dominance test) and we tried to represent the relative importance, by quadrats, for Angiosperms. We display the vegetal zonation in the side of the lagoon. The terrestrial species are distributed especially along the winter inundation fringe and the species of salty soils in the summer waterside fringe. In the intermediate zone are located species which can stand more water and more salinity.

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Laboratoire de Biologie Végétale, E.N.S., TUNIS     

Etude cytologique de la prehypophyse du pigeon pendant la couvaison et la lactation

Résumé Les hypophyses de 22 Pigeons des deux sexes sacrifiés soit pendant la couvaison, soit pendant la période de soins aux jeunes, ou lactation, ont été comparées à celles de 43 Pigeons des deux sexes, adultes non lactants ou prépubères, normaux ou soumis à divers traitements (lumière permanente, métopirone, thyroxine). Elles ont toutes été examinées en microscopie optique et 13 d'entre elles ont été en outre étudiées au microscope électronique.Sur la base de leurs affinités tinctoriales et de leurs caractères histochimiques, 6 types cellulaires ont pu être identifiés (Tableau 2). Seuls trois d'entre eux, tous localisés dans le lobe céphalique de l'adénohypophyse, sont intensément modifiés pendant la couvaison et la lactation. D'une part, la cellule eta, érythrosinophile, et la cellule kappa, cyanophile mais PAS négative, sont fortement stimulées. D'autre part, la cellule delta, cyanophile et PAS positive, est déprimée.Les caractères ultrastructuraux de ces six types cellulaires sont décrits et plus particulièrement ceux des cellules sollicitées pendant la couvaison et la lactation.La confrontation de l'évolution respective de ces trois types cellulaires avec celle de la paroi du jabot montre que la cellule eta érythrosinophile élabore la prolactine. La signification fonctionnelle de la cellule kappa demeure hypothétique: elle élaborerait l'hormone mélanophorotrope, MSH. La valeur thyréotrope des cellules delta est démontrée par les modifications déclenchées à leur niveau par des injections de thyroxine; ces modifications sont identiques à celles observées pendant la lactation.

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Summary The pituitaries of 22 pigeons of both sexes fixed either during incubation or lactation (care for the young) were compared with those of 43 adult pigeons that were either adult but non-lactating, or prepuberal; these were either normal or variously treated (permanent illumination, administration of metopirone or thyroxin). All were studied with the light microscope and 13 among them were also examined with the electron microscope. On the basis of their staining properties and histochemical characteristics, six cellular types were identified. Only three among these, all located in the cephalic lobe of the adenohypophysis are intensively modified during incubation and lactation On the one hand, the eosinophilic eta cell and the cyanophilic but PAS-negative kappa cell are strongly stimulated. On the other hand, the cyanophilic and PAS-positive delta cell is depressed. The ultrastructural characteristics of these six cell types are described, in particular of those involved in incubation and lactation. Comparison of the development of these three cell types and of the crop shows that the eta cell furnishes prolactine. The functional significance of the kappa cell remains hypothetical; it may produce the melanophorotropic hormone (MSH). The thyrotropic nature of the delta cell is demonstrated by its modification in response to thyroxin administration; these changes are identical with those observed during lactation.

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Ce travail est dédié à M. le Prof. Bargmann à l'occasion de son 60^e anniversaire et en témoignage de notre respectueuse admiration.

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Avec la collaboration technique de Mmes Denise Lescanne, et Renée Picart et de M. Claude Pennarun pour les photos.     

Etude de l'evolution des activites des enzymes mitochondriaux de l'hepatocyte au cours du developpement du rat

Study on the evolution of mitochondrial enzyme activities in hepatocyte during rat development

Some constitutive enzymes of the three isolated fractions of mitochondria outer membrane, inner membrane and matrix, have been investigated in rat hepatocyte during a period varying from the foetal state to the 15th day after birth.

In the three mitochondrial fractions, activities of the studied enzymes present different evolutions. In the matrix, the tricarboxylic enzyme activities have already reached their normal values before birth. In the outer membrane, the NADH-cytochrome c reductase activity increases regularly, in the same way as that of the endoplasmic reticulum NADH-cytochrome c reductase. In the inner membrane, the oxygen consumption is very low before birth, then increases suddenly from the 5th to the 8th day after birth, when it reaches the normal values. The limiting factor of the respiratory chain activities is neither cytochrome oxidase nor the first dehydrogenases.     

Etude des paraios de levures du genre rhodotorula IV. variation de la teneur en chitine

A study of the chitin contents in Rhodotorula yeast walls indicates that the contents of this amino polysaccaharide may vary from 0.58 to 12% according to the yeast and depending on the culture conditions.The variations of the glucosamine concentrations, estimated by direct determinations on the cell walls, do not reflect the modifications of the chitin contents.Depending on the culture conditions, the yeast cell walls possess structures which are differently degraded by enzyme actions. Cell walls with high glucosamine content, but low amino-acids content, are the more easily degraded.     

Etude ecologique et floristique du plancton de cinq biotopes de la vallée de la Dyle

Sans résumé     

Etude infrastructurale de la stipule de Vicia faba L. au niveau du nectaire

Summary In the extrafloral nectary of the broad bean there is evidence of two fundamental types of cells: one with dense hyaloplasm, well developed ergastoplasm and golgi apparatus, all features of glandular cells, and another with opposite features. The cells of the head of the secretory hairs and those of the subjacent epidermis which are not prolonged with such a hair are of the first type. The epidermal cells prolonged with a hair and the pedicellar cell of this hair are of the second type. Moreover, the companion cells of the subjacent conducting bundle look like cells of the first type, especially those of the head of the secretory hairs owing to their numerous wall protuberances. Cells of the second type are presumably involved in transit processes between phloem and trichome, and cells of the first type in excretory processes.

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Ce travail fait partie d'une Thèse de Doctorat d'Etat sur la cyto-physiologie des nectaires. — (Travail effectué au Laboratoire de Bot. Appl. et Microbiologie et au Centre de Microscopie électronique de la Faculté des Sciences de Bordeaux (France).     

Nouvelle nomenclature lithostratigraphique « événementielle » pour le Jurassique de la Tunisie atlasique

The various and heterogeneous nomenclatures previously proposed for the Jurassic of both central and northern Tunisia were examined and revised. In this work we propose a new lithostratigraphic chart taking into account the progress of our knowledge on the sedimentological and palaeontological (ammonites) aspects obtained during the two late decades. This chart summarizes and restores the major sedimentary and stratigraphic events (discontinuities) recorded in the Jurassic rocks. It outlines the main phases of the palaeogeographic evolution of the Tunisian atlasic domain during the Jurassic, in relation with the main controlling factor (tectonic and eustatism), which accompanied the tethyan rifting.     

Etude critique des distinctions tinctoriales effectuées parmi les cellules endocrines de la muqueuse fundique du Lapin

Résumé Si chez des animaux intacts ou ayant reçu de la L-Dopa on compare les images d'une même coupe traitée d'abord selon Falck, ensuite colorée ou imprégnée selon divers procédés, on peut constater les faits suivants: la formaldéhyde confère une fluorescence jaune terne (Jt) à des cellules GIC dépourvues d'argyrophilie selon Sevier et Munger mais imprégnées en technique de Grimélius, colorées par le picroponceau et l'hématoxyline au plomb. Il y a approximativement trois fois plus de cellules imprégnées selon Grimélius que de cellules fluorescentes; parmi elles 1/3 environ réagit fortement en technique de Sevier et Munger (cellules à sérotonine), 1.3 réagit faiblement (cellules SM), 1/3 ne réagit pas du tout (cellules D et Jt). Les cellules SM correspondent aux «ECL cells» bien que dépourvues d'amine et d'argentaffinité (Fontana-Masson); elles se divisent en GIC et non GIC, les premières sont ou non colorables par l'hématoxyline au plomb, les secondes ne le sont pas.

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Critical study of tinctorial distribution proposed among endocrine cells of the fundic mucosa in the rabbit

Summary Whether the same endocrine like cells are reactive towards different staining reactions has been hardly examined in normal and L-Dopa treated rabbits for distinction of cell types. Samples were first freeze-dried, exposed to formaldehyde vapours (standard Falck technic) and sections photographied. Thereafter they became further hydrated and were stained with silver according to Fontana-Masson or Grimelius or Sevier-Munger, or with ferric ferricyanide or lead hematoxylin or picroponceau.Formaldehyde condensation induced a bright yellow fluorescence in serotonin cells and revealed a dim yellow (jaune terne: Jt) unexpected fluorescence in others scarce cells. The laters were non argentaffin, unreactive with Sevier-Munger method but argyrophilic in Grimelius technic, stained blue black by lead hematoxylin and red by picroponceau; there are a part of the GIC or APUD cells group.Grimelius reaction stained three times as many cells as fluorescence did. With Sevier-Munger method, heavily darkened (serotonin cells), slightly reactive (Sevier-Munger or SM cells) and unreactive cells (D and Jt cells) roughly represented 1/3 each of all Grimelius positive cells. ECL cells according to Capella et al. (1969) apparently corresponded to SM cells; since all fluorescent cells are strongly argentaffin and reactive with Sevier-Munger method, since they are too much scanty to include EC and ECL cells it is conclude that ECL cells failed to exhibit fluorescence and to store serotonin: furthermore taking hypothetically ECL cells into fluorescent cells it would imply to blend D cells and SM cells which is at variance with earlier observations of unreactivity of D cells in Sevier-Munger technic at the ultrastructural level. SM cells population seemed heterogenous: only some of them were GIC and only some of the laters were stained by lead hematoxylin; however it is not clear how much the L-Dopa administration effect the second staining possibly causing erroneous reactions.

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Avec la collaboration technique de Mme A. de Gouyon.     

Etude du processus de transformation des acides di-et tricarboxyliques chezPenicillium Brevi-compactum

Résumé L'étude du processus de transformation des acides di- et tricarboxyliques chezP. brevi-compactum a permis d'établir que le cycle deKrebs ne se déroule pas chez cette moisissure. Les résultats des recherches menées jusqu'à ce jour font au contraire supposer, avec grande vraisemblance, que le processus étudié est identique au schéma proposé parChrzaszcz etTiukow. Quant à l'acide α-cétoglutarique, il semble qu'il soit synthétisé par condensation oxydative d'une molécule d'acide pyruvique et d'une molécule d'acide acétique.