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.     

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.).     

La Structure Fine de Chlorogonium elongatum. I. Etude Systematique au Microscope Electronique.

The flagellate Chlorogonium elongatum has been studied in the electron microscope by thin-sectioning techniques. The nucleus, limited by a porous membrane, contains a large nucleolus and some dense masses, probably of chromatin. When the medium is rich or the culture young, the chloroplast has few lamellae, and very few pyrenoids. Inversely, when the medium is poor or jthe culture old, the lamellae are abundant, appearing as piled discs or as a tortuous lamellar system. The pyrenoids are then numerous and are surrounded by starch grains. They are composed of an opaque, finely granular substance, and are never traversed by chloroplast lamellae. The stigma, within the chloroplast, is a circular or oval plate composed of a single tier of dense granulations. The cytoplasm contains mitochondria which are concentrated near the pellicle of the cell, an endoplasmic reticulum, an abundance of ribo-nucleoprotein particles or ribosomes, and a Golgi apparatus. These organelles resemble those observed in other protozoa. The two fiagella are encased in cylinders situated at the anterior end of the cell. At the base of the fiagella are the basal corpuscles or kinetosomes, which repose within a cupule. A dense granule which probably corresponds to the centrosome appears near this structure.     

Etude Morphologique du Cilié Hymenostome Disematostoma colpidioides von Gelei, 1954

Disematostoma colpidioides von Gelei, 1954, is a Peniculina which stands out principally by a very markedly-twisted shape, resulting from the allometric growth of some of the right somatic kineties, and by the sigmoid curvature of the postoral suture. During the fission of the macronucleus, it is possible to observe the expulsion of a small chromatic mass which degenerates quickly. A part of the buccal apparatus undergoes a dedifferentiation during the encystment, so that the three "peniculi" disappear while the vestibulary kineties persist.     

Etude au microscope electronique du cycle cuticulaire au cours du 4ème stade larvaire chez Locusta migratoria

Résumé La structure du tégument de Locusta migratoria est étudiée au cours du quatrième stade larvaire.On examine la formation de la nouvelle cuticule et plus particulièrement celle de l'épicuticule, ainsi que la structure des cellules hypodermiques. La cuticule du prochain stade apparaît au jour 4 du stade IV sous forme d'une lame trilaminée, discontinue, puis continue, à la surface de la cellule hypodermique.La formation de cette couche de cuticuline (au sens de Locke) représente le point de départ du cycle cuticulaire et constitue l'évènement cyclique fondamental.

---

Summary The structure of the integument of Locusta migratoria during the fourth larval instar is studied.The formation of the new cuticle and especially that of the epicuticle is examined as well as the structure of the hypodermic cell. The cuticle of the following instar appears at the 4th. day of the 4th. larval instar, as a trilaminate layer at the surface of the hypodermic cell. At first disrupted, this layer becomes continuous afterwards.The formation of this cuticulin layer (in the sense of Locke) is the beginning of the cuticular cycle and is the fundamental cyclic event.

     

Ultrastructures Corticales du Cilié Holotriche Drepanomonas dentata Fresenius, 1858

SYNOPSIS. A study of the fine structure of the cortex of the ciliate Drepanomonas dentata revealed that it has a double cuticular membrane with a "lamina corticalis" and fibrous trichocysts with a quadripartite apical point. These characters warrant its assignment to the family Microthoraddae.     

Etude topographique des plaques motrices au niveau des muscles respiratoires du Chat

Résumé A pH 5,57, en modifiant les durées de fixation et d'incubation, il est possible d'appliquer la technique de coloration histochimique des plaques motrices de Koelle et Friedenwald à des muscles ou à des prélèvements tissulaires d'épaisseur allant jusqu' à 3 mm.Cette technique nous a permis de repérer, chez le Chat, la situation des jonctions neuro-musculaires des muscles intercostaux par rapport aux arcs chondro-costaux. La topographie des plaques motrices du diapragme a été également précisée.

---

Summary At pH 5.57, with modifications of the times of fixation and incubation, it is possible to apply the Koelle and Friedenwald histo-chemical technique to muscles or samples of tissues 3 mm thick. This technique allows to study, in the cat, the localization of end-plates in the intercostal space. The topography of the diaphragmatic end-plates has been studied.

---

---

Attaché de recherche à l'I.N.S.E.R.M.

---

Nous remercions Mme. A. Rousseau pour sa collaboration efficace lors de la phase initiale de ce travail.     

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.     

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.

---

---

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).     

Caractéristiques Ultrastructurales du Cortex et des Membranelles du CiliéEspejoia mucicola (Oligohymenophora, Hymenostomata, Tetrahymenina)

RESUME. L' étude détaillée du cortex et des organelles buccaux adoraux d' Espejoia montre que ce Cilié possède une organisation ultrastructurale comparable à celle des Tétrahyméniens. Tout en restant conforme au plan général d'organisation de ces derniers, des variations spécifiques décelées tant au niveau du cortex d'une part, que des membranelles, d'autre part, font ressortir des affinités trés marquées pour le genre Glaucoma et autres Ciliés voisins. En conséquence, en nous appuyant en outre sur les données récentes de la morphogenèse, nous confirmons la position d' E. mucicola parmi les Tetrahymenina, dans la famille des Glaucomidae.     

Morphogenèse de Régénération chez le CiliéCondylostoma magnum (Spiegel): Etude ultrastructurale

SYNOPSIS Cortical events occurring in the course of regeneration in Condylostoma magnum (Spiegel) were studied by electron microscopy. The zone of regeneration is very rich in vacuoles and small vesicles formed from the plasma membrane. Multiplication of kinetosomes starts on the left side of kineties in the V-shaped left ventral area, normally implicated in stomatogenesis, at the level of the anterior kinetosomes of the somatic pairs. The proliferation proceeds by the appearance of young kinetosomes most often orthogonal to the old ones. This process of multiplication is very rapid and terminates in the formation of an “anarchic field” in which one observes that: (a) the newly formed kinetosomes do not possess all the associated postciliary fibers; and (b) when these fibers are detected, the kinetosomes are not in the same orientation. Differentiation of the adoral organelles takes place in the left part of the field (left primordium) by an alignment of the kinetosomes into 2 rows for each organelle (oriented perpendicularly to the antero-posterior axis of the ciliate), of which only one has the postciliary fibers. Ciliatogenesis occurs in numerous kinetosomes of the anarchic field; in certain kinetosomes it is achieved at the onset of their arrangement into organelles and is concomitant with growth of the nematodesmata. The 3rd (anterior) row of the organelles, the interkinetosomal desmata, and connections among neighboring organelles appear only secondarily. Differentiation of the paroral cilia occurs later. It takes place in the interior of the primordium, whose organization is primarily anarchic, and is accompanied by a progressive resorption of the major part of the newly formed kineties. Numerous kinetosomes of the right field have the associated postciliary fibers, which are not found at the level of the regenerated “polystichomonad” (paroral organization characteristic of C. magnum). Finally, the formation of new kinetosomes within a somatic kinety at the time of its elongation is described.     

LA SYNTHÈSE DE L''ADN MITOCHONDRIAL CHEZ TETRAHYMENA PYRIFORMIS : Etude Radioautographique Quantitative au Microscope Èlectronique

Electron microscopic radioautography has been used to study the synthesis of mitochondrial DNA after incorporation of thymidine-³H by cultures in logarithmic phase of Tetrahymena pyriformis during periods ranging from 15 min to 12 hr. The great majority of silver grains are distributed over the macronuclei, the micronuclei, and the mitochondria. The intensity of the label over the entire mitochondrial population is a function of the length of the incubation period within the time interval considered. The intensity of the mitochondrial label was compared with that of the nuclear label. Mitochondria incorporate at the same rate whether the nuclei are synthesizing or not. This persistence of mitochondrial incorporation in the absence of nuclear incorporation excludes the hypothesis of a nuclear origin for mitochondrial DNA. We are not able to determine whether the apparent continuity of synthesis in the entire mitochondrial population of a cell actually represents a series of asynchronous discontinuities.     

Les protéines non hémoglobiniques érythrocytaires du poulet : Etude immunologique de leur évolution au cours du développement

By use of Laurell's method, the quantitative evolution of three antigenic components of chicken erythrocyte non-hemoglobin proteins has been followed during the course of development. One of the constituents has been characterized as the yellow component previously described and its evolution has been confirmed. The significance of these modifications is discussed.     

TEP/TDM au FDG et bilan initial des lymphomes : du diagnostic au pronostic

Lymphoma represents a very heterogeneous pathologic disease group and its initial assessment, treatment strategy and prognosis is closely related within each histological subtype. The diagnosis of lymphoma disease is often due to the development of a tumour mass at a lymph node area, or within an organ with or without systemic symptoms. However, all these signs remain non specific. Biopsy is the only reliable diagnostic tool, which can be carried out surgically or guided by the morphological and functional imaging. Once the histological diagnosis is determined by the WHO classification, the staging procedure aim is to provide the prognosis to assist the therapeutic decision. Morphologic imaging primarily based on CT remains the reference in exploring most cases. But in the last decade, the introduction of functional imaging using FDG-PET/CT has dramatically changed the therapeutic management of lymphoma. The additional clinical value provided by initial FDG-PET/CT could lead to an alteration of the therapeutic strategy, as well as to the optimization of radiation therapy or to the establishment of prognostic score and lead to improved lymphoma patient survival in the future.     

Synthèse des RNA au cours de la germination du radis

RNA synthesis in radish is studied during the first stages of germination. The radish seeds allowed to germinate in the dark, on distilled water, synthesize ribosomal RNA and accumulate a particular RNA, not incorporated in ribosomes. The results of ³²P incorporation in RNA of radish seedlings indicate a progressive formation of ribosomal RNA. Two species of rapidly labelled RNA are synthesized. With labelling time, their chromatographic behaviour on MAK columus evolves, while their electrophoretic characteristics remain stable. It is assumed that these two species are involved in ribosome formation. In vivo experiments with chloramphenicol support this conclusion. RNA which accumulates during germination, could be a particular type of ribosomal RNA which could be enable, under the definite culture conditions, to enter into ribosomal structures.