Les Tentacules d'Ephelota; Etude au Microscope Electronique.

SUMMARY. The central canal of the suctorial tentacle of Ephelota is limited by a fine pellicle composed of numerous longitudinal fibrils and bearing 16–18 membrano-fibrillar ridges arranged radially in the lumen of the canal. This structure resembles that of the myonemes in the heterotrichous ciliate Stentor.
The prehensile tentacle of Ephelota contains 4–6 axial protein fibers each consisting of a lamello-fibrillar bundle and isolated from one another by thin intracytoplasmic membranes.
In both types of tentacle the cytoplasmic portion is immediately limited by a very thin pellicle which is continuous with the "epiplasmic membrane" and covered by the alveolar cuticle which envelops the entire body of the ciliate.     

Etude au Microscope Electronique du CiliéPseudomicrothorax dubius Maupas

SYNOPSIS. Ciliates of the genus Pseudomicrothorax present, at the ultrastructural level, some remarkable peculiarities from the points of view of both cytology and taxonomy. The trichocysts have 4 apical blades which are characteristic of the family Microthoracidae; the curious subcuticular membrane is found in the Microthoracidae and, admittedly less typically, in the Nassulidae; the cytopharyngeal armature is exactly comparable to that of the Nassulidae. These facts, like those of Thompson and Corliss on the organization of the oral ciliates, show—as suggested by Corliss–that the taxonomic position of the genus Pseudomicrothorax throws light on certain stages of the evolution of the Ciliata.     

La Sporogenèse chez la Coccidie Aggregata eberthi. Etude en Microscopic Electronique

SYNOPSIS. The structure of the oocyst and formation of sporozoites of Aggregata eberthi were studied with the electron microscope. After penetration of the microgamete, a cyst wall containing fine projections is formed beneath the "anhist" layer which is pushed away. The cytoplasm is retracted beneath the cyst wall and is irregular in outline. Lipid inclusions are abundant, while paraglycogen is less so. Vacuoles present in the early stages of development may be instrumental in elaboration of the cyst wall. Granulations appear in the early oocyst cytoplasm and form large compact masses in the sporoblasts, assuming a crystalline appearance (crystalloid) in the sporozoites. The sporoblasts are separated by the coalescence of vesicles. Each sporoblast is surrounded by an epispore and a striated endospore which is perforated by the "dehiscence device." Three sporozoites of classical structure are formed in each sporoblast.     

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).     

Observations au Microscope Electronique D'Appareils Nucleolaires dans la Surrenale du Cobaye,du Hamster et du Chat

Sans résuméAvec la collaboration technique de Mme Cotte (C. N. R. S.).     

The crystalline glycoprotein cell wall of the green alga Chlorogonium elongatum: a structural analysis.

Members of the Chlamydomonaceae, mostly single-celled green algae, have been shown to contain a crystalline glycoprotein cell wall component. Most of the species examined fall into a class of algae whose walls have an identical crystalline unit cell. Chlorogonium elongatum has been chosen as a representative of this class in order to investigate in more detail its cell wall structure. The alga has a spindleshaped cell wall which retains its asymmetric shape on isolation. Sections from walls fized in the presence of tannic acid clearly reveal a regular subunit monolayer, about 20 nm thick, within the wall. Sodium dodecylsulphate (SDS) polyacrylamide gel electrophoresis shows the presence of at least 2 major glycoprotein species in the wall. Negatively stained purified cell walls demonstrate the crystalline nature of the cell wall. Optical diffraction of bright-field images and direct electron diffraction both give clear diffraction patterns whose spacings extend out to 3 nm and fall on a reciprocal lattice whose vectors describe a 2-dimensional unit cell within the wall 21.5 nm X 7.0 nm and an included angle of 80 degrees. Lattice defects within the cell wall are revealed by both negative staining and surface replication. Through-focal series were used to choose images with the optimal degree of underfocus for image processing. Linear integration and optical filtering of such images gave essentially the same result. A similar image was also obtained by computing the autocorrelation function of the amplitudes in the electron-diffraction pattern and the optical-diffraction pattern of the in-focus image. On the basis of these data a 2-dimensional model of the crystalline cell wall layer is presented.     

Etude experimentale de l'immunite a mediation cellulaire au cours des dermatophyties

Résumé A différents temps après le début de l'infection, puis de la réinfection du cobaye par T. mentagrophytes, furent pratiqués des tests de détection de l'hypersensibilité retardée in vivo (intra dermo réaction) et in vitro (inhibition de la migration des macrophages péritonéaux) ainsi qu'un test destiné à mettre en évidence la secrétion de lymphotoxines actives vis à vis des éléments fongiques.Les résultats obtenus concernant l'évolution cinétique des réactions plaident en faveur de la plus grande sensibilité du test d'inhibition de la migration des macrophages pour la détection de l'hypersensibilité retardée. Ils confirment le rôle prépondérant des réactions de type cellulaire dans la résistance et soulignent la particularité de ce modèle expérimental oú se manifestent des phénomènes d'immunité locale. L'ensemble de nos résultats et, notamment, la démonstration de l'existence de médiateurs d'origine lymphocytaire toxiques pour les spores de T. mentagrophytes sont discutés dans le cadre de la réaction cutanée à l'agression parasitaire.     

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.      

Etude du phytochrome detectable,in vivo dans les graines de Cucurbita pepo L. au cours des differentes phases de la germination

Summary In dry gourd seeds all the phytochrome is in the P_fr form. The increase of phytochrome content from the beginning of hydration involves two phases, A and B, in the embryonic axis as well as in the cotyledons. Cycloheximide does not prevent the appearance of P_r during phase A. We assume that P_r is gradually released from an inactive complex. On the other hand phase B is inhibited by cycloheximide; this could mean that a de novo synthesis of P_r occurs.Some experiments indicate that the phytochrome which is localized in the embryonic axis may be involved only in the germinating process.The phytochrome which is synthesized during phase B disappears when the seeds are irradiated with red light, while the original phytochrome does not.According to our data it seems necessary to lay down a new and precise definition of the germination process.     

La microflore de diatomées au passage mio-pliocène en Corse

The “Aleria formation”, described in northeastern Corsica, consists of siliciclastic deposits referred to a deltaic environment and comprises diatomitic lenses exposed at Casabianda. The Aleria formation fills a depression of the Messinian erosional surface and is overlain by Early Pliocene sediments in several places. This suggests a late Messinian-earliest Pliocene age. Diatom microflora is well-preserved and contains 59 species. Pennates indicate a very large diversity with 54 species, while Centrics are represented only by five species. Diatom assemblages show a relative constant composition along the studied interval. The species Aulacoseiragranulata is the dominant taxon with about 90% in all samples. Taxa are of different salinity classes and different modes of life (planktic, tychoplanktic, benthic, epiphytic…), suggesting multiple environmental factor interactions. The environmental model suggested by sedimentological and biological data led as to assume a pond-like coastal receptacle common in deltaic system. This receptacle was slightly influenced by the close marine waters and was supplied by permanent freshwaters from continental run-off and alluvial sheet. This model based on diatom assemblages provides new data for palaeoenvironmental and chronological interpretations of the so-called Messinian Lago-Mare deposits.     

Effets de la novobiocine sur le fonctionnement du foie: I. Etude clinique

A case of novobiocin-induced jaundice is described in which the main feature was elevated unconjugated bilirubin in the serum. No evidence of hemolysis or hepato-cellular failure was demonstrated.The effect of novobiocin on serum bilirubin was studied by administering 2 g. of the drug daily in four divided oral doses for two days. An increase in serum unconjugated bilirubin was nearly always observed in the normal subjects and in patients with cirrhosis of the liver. This rise was particularly significant in three patients with hemolytic anemia and in two patients with Gilbert''s disease. After an oral dose of 500 mg. the BSP clearance was decreased after one hour and it was close to normal after three hours. Since hemolysis is not responsible for this elevation of serum unconjugated bilirubin, the novobiocin-induced hyperbilirubinemia appears to be due to a direct effect of the drug upon the liver.