Distribution et activités des alcaloïdes défensifs des Coccinellidae

From a survey of 30 species and varieties of ladybugs the presence of alkaloids appears to be correlated with the existence of aposematic colour and not with being carnivorous or phytophagous. The alkaloids described until now all belong to the Coccinellini and are closely related, but other types of bases have been detected in some genera. The observed distributions are in agreement with the modern taxonomy of the family.Ladybug alkaloids constitute an effective defence against ants, Myrmica rubra, and quails, Coturnix coturnix, but all the beetles containing alkaloids do not possess the same degree of protection. Individual quail react differently towards moderately protected species.The bioassay used for the first isolation of coccinelin is described. The repulsive activities of aqueous solutions of coccinellin and convergin towards ants have been compared.     

Résumés des communications orales et affichées

XVIème Congres de la Societe d’Andrologie de Langue Francaise Issy-Les-Moulineaux 9-11 Décembre 1999

Résumés des communications orales et affichées     

Etagement des algues et des invertébrés sessiles dans l'Archipel de Glénan

The Glénan Archipelago was investigated, from the surface to a depth of 60 m, byScuba diving. Four distinct communities (“peuplements”) have been determined that fit into the system of zonation defined by the Genoa Symposium (1957). The results are compared with observations made in the English Channel (Cabioch 1968) and in the Atlantic Ocean (Glemarec 1971). Since illumination depends upon the angle of the rocky face, photophilic species exhibit a maximum range when the rock surfaces are horizontal. The sublittoral zone is dominated by laminarians. They form two distinct communities with the animal and vegetal species they overshadow. The upper community is characterized byLaminaria digitata (Linné)Lamouroux (horizontal rocky face from 0 to 6 m; vertical rocky face from +0.5 to ?3 m). The lower cummunity, characterized byL. hyperborea (Gunner)Foslie has a greater vertical extension (horizontal: ?6 m to ?26 m; vertical: ?3 to ?30 m). The circalittoral zone is colonized by several animal species growing in a ramified manner: the upper community is characterized by Axinellidae (?30 m), the lower byDendrophyllia cornigera (Lamarck) (?55 to ?60 m). Upright algae disappear somewhere between ?40 and ?47 m.     

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.     

Modifications des comportements liés au SIDA

Since the seropositivity declaration, a certain number of assests appears and express a psychic distress in man. This psychic “shock” doesnt always show itself directly. When it appears it’s often as form of “signifiant “having said that phoneme, word, representing, symbolizing what spring up without some one knowing, a truth of his desire. The first of these assests is the word Revelation This term means not as the surprise as the time lag between a “fashion of life” and its results. As a matter of fact, they must be less surprised than witness of their life always in danger. This word of “revelation” lays us in a sacred country, but also in the dark, the mysterious and experience; saying always “testing something” Other meaning, Aesthetisation Current events media supplies evenly gushing examples of Estheticism. By estheticism, we must understand as much documents where the body is left to the others. Stain and guilt, last stand, “dramatic exist”, taking fligth, so much examples of “desecration” or “redemption”. Other assest, Convocation It’s an experience of the request. Often the person life is marked out a succession of invocations and/or provocations before than the virus intervenes who, in the psychic representations that it conveys, changes the status of requests. It’s in this change of status that people are affected and the doctor can look for an application who arouse changes of behaviours. Revelation, aesthetisation, convocation, these three words part of method where the person works by oscillation between, first time a position of subject, it means a psychic work of hesitations, withdrawal, desire, and also a position of being, it means acting, an act where all sense is vacant. The notions of “risk behaving” and “ordalic behaving” help us to better understand and separate all these behaviours which some people will be infected. To take a risk is the behaviour of “human condition”, like the venial sin defins the human being, only the ordalic behaving shows a desperate endeavour with a meeting of a sort of sovereignty, a next world not defined. The work of this whole on the modifications tie up the AIDS, can give us a reflection about the S.C.D. where the notion of risk is rarely absent.     

L’automatisation des sérologies auto-immunes

Pendant longtemps les analyses d’auto-immunité ont été réalisées de fa?on manuelle, en utilisant des techniques parfois artisanales. Plusieurs facteurs conduisent aujourd’hui les laboratoires à automatiser ces examens.     

Role respectif des males et des femelles dans la formation des sexués néoténiques chezCalotermes flavicollis

Résumé ChezCalotermes flavicollis, la formation des sexués néoténiques est plus facile, ou plus rapide, dans le sexe femelle que dans le sexe mâle.Les sexués femelles montrent un pouvoir inhibiteur à l'égard des individus femelles; les sexués mâles inhibent les mâles de façon moins complète; la stabilisation complète peut être obtenue dans les élevages unisexués, formés uniquement de mâles ou de femelles.La régulation du nombre des néoténiques ne se fait pas de la même façon dans les élevages et dans les élevages . Dans les premiers, 2 néoténiques subsistent, quelquefois 3; dans les seconds ne persiste qu'un seul néoténique , rarement deux.Ces résultats mettent en lumière le rôle différent joué par les mâles et les femelles dans les sociétés de Termites.     

Les virus des eaux usées et leur élimination au cours des traitements des effluents pollués

Viruses are a biological pollution in wastewaters. Their elimination results from treatment processes of polluted effluents in the sewage treatment plant or in the lagooning pilot plant. Bacteriophages are regarded as viruses models and as indicators of faecal contamination. In an expiremental study, two pilot plants laboratories have been used (natural lagooning and activated sludge pilot) to follow and evaluate the elimination rate of somatic coliphage X-174 or the ARN F-specific one MS2. The two phages removal, ranging to 99 % in the two systems, are related with previous values on enteric viruses. The main factors of viral removal and inactivation (adsorption to solid matters, microbial activities, solar radiations, dissolved matters) have been studied too. Adsorption of infectious particles to solid matters is a very significant process. This was obtained in the pilot plant laboratory experiment and in in vitro study (X-174 or MS2 in the presence of the kaolinite or the montmorillonite). Otherwise, 12 hours of solar rays exposition were efficient ro inactivate nearly the whole phagic suspension. The ciliate protozoan Tetrahymena pyriformis does not seem to have an important role for elimination of phages (X-174 and MS2.     

Mode d'action et propriétés des facteurs inducteurs issus du mésenchyme gastrique et des mésenchymes hétérologues

Résumé Des expériences d'associations d'épithélium gastrique de foetus de Lapin et de mésenchyme homologue ou hétérologue, partielles ou par membrane filtrante interposée, mettent en évidence l'existence de deux types de facteurs inducteurs.Le premier facteur induit la morphogenèse de l'épithélium. Il est thermostable et hautement diffusible.Le deuxième facteur, organospécifique, est plus ou moins favorable à la différenciation de l'épithélium gastrique suivant la nature du mésenchyme. Faiblement diffusible et thermolabile, il est élaboré dans la phase cytoplasmique des cellules mésenchymateuses.

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Action and properties of inductive factors proceeding from gastric and heterologous mesenchymes

Summary Experimental associations of gastric epithelium of the Rabbit foetus with homologous or heterologous mesenchyme, separated by membrane filter or partially associated, permit us to prove the existence of two types of inductors.The first factor induces the epithelial morphogenesis. It is thermostable and highly diffusible.The second factor, organospecific, is more or less favorable to the differentiation of the gastric epithelium according to the nature of the mesenchyme. Lightly diffusible and thermolabile, it is elaborated in the cytoplasmic phase of the mesenchymal cells.

     

Identification des cellules hypophysaires sécrétant l'ACTH chez le rat

Résumé Dans le but d'identifier la cellule hypophysaire responsable de la sécrétion d'ACTH chez le rat, des études morphologiques, en microscopie optique et électronique, furent entreprises chez des animaux surrénalectomisés, c'est-à-dire dans des conditions où la sécrétion d'ACTH est spécifiquement augmentée. Le prélèvement des hypophyses fut effectué à des intervalles allant de 1 à 21 jours après surrénalectomie. Des hypophyses d'animaux surrénalectomisés et traités par la dexaméthasone, un inhibiteur de la secrétion d'ACTH, furent également étudiées. Il découle de ces expériences qu'un type cellulaire est stimulé en même temps que la sécrétion d'ACTH augmente. Cette cellule, hypertrophiée après surrénalectomie, possède une forme irrégulière et est très souvent en contact avec les cellules somatotropes; son ergastoplasme peu développé contraste avec un appareil de Golgi très important. Les granules secrétoires corticotropes ont un diamètre d'environ 200 m, sont peu abondants et disposés le long de la membrane cellulaire. Ces granules n'ont cependant pas été caractérisés en microscopie optique. L'administration de dexaméthasone provoque une régression spécifique de la cellule corticotrope ainsi qu'une accumulation des granules sécrétoires dans le cytoplasme. Chez l'animal intact, il devient possible d'identifier la cellule corticotrope qui possède les caractéristiques générales de la cellule stimulée, mais dont le cytoplasme et l'appareil de Golgi sont peu importants.

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Identification of the ACTH secreting cells in the rat pituitary

Summary In order to clarify the identity of the ACTH-secreting cells in the rat pituitary, morphological studies were performed in adrenalectomized rats which have a specific increase in ACTH secretion. Pituitaries were removed and fixed for both light and electron microscopy at different time intervals (1 to 21 days) after adrenalectomy. Pituitaries of adrenalectomized animals which received dexamethasone, a potent inhibitor of ACTH secretion, were also studied. In these experiments, it was found that a specific cell type was stimulated as ACTH secretion was increased. This cell, which became enlarged after adrenalectomy, is characterized by an irregular shape and frequent association with somatotropic cells. The rough endoplasmic reticulum was poorly developed in contrast to a prominent Golgi apparatus. The secretory granules of this corticotropic cell were about 200 m in diameter and located in a single row along the plasma membrane. By light microscopic examination, these secretory granules could not be clearly identified. Dexamethasone administration provoked a specific decrease in size of corticotrophic cells, as well as an accumulation of secretory granules. Identification of corticotrophic cells in control rats was facilitated by comparison with those of adrenalectomized rats. In both cases, the general appearance of this cell type was similar except for size difference. Also in the control animals the Golgi apparatus was less prominent than in adrenalectomized rats.

Boursier du Conseil de la Recherche Médicale du Québec.     

Intérêt potentiel des images paramétriques des temps d’éjection et de relaxation en tomoscintigraphie des cavités cardiaques dans l’évaluation des cardiopathies asynchrones

Intraleft dyssynchrony is strongly correlated to contractile dysfunction associated to severe heart failure. Dyssynchrony is also a predictive marker for cardiac resynchronization therapy response. We measured dyssynchrony values for both ventricles from gated blood pool SPECT images.Material and methodsThree groups of patients were sampled from normal patients (n = 7), mild heart failure patients (n = 24) and severe heart failure patients (n = 9). Time-derivative parametric images were obtained from 24-time bins gated blood pool SPECT data. We measured intraleft and interventricular contractile and relaxing dyssynchrony values from these images.ResultsIntraleft dispersions values linked to ventricular peak emptying rate were 107 ± 21 ms, 141 ± 58 ms and 515 ± 104 ms for each of the three groups. The values linked to left ventricular peak filling rate were 122 ± 62 ms, 219 ± 117 ms and 603 ± 164 ms respectively. Statistical significant differences (p < 0.01) were observed both for contractile and relaxing phases for severe heart failure patients. Mild heart failure patients had isolated statistical significant (p < 0.01) alterations of the ventricular relaxing phase. Correlation between isotopic dyssynchrony values and left ejection fraction led to a R square coefficient of 0.71 and 0.64 for time to peak emptying and to peak filling respectively. Correlation to QRS width values led to a R square coefficient of 0.76 and 0.62 respectively.ConclusionVentricular dyssynchrony correlated to the importance of the ventricular mechanical dysfunctions is a robust predictor of heart failure. Separate analysis of contractile and relaxing dyssynchrony may lead to a better understanding and characterization of the mechanical dysfunctions involved in heart failure.     

Le phénomène de superparasitisme chez les parasites oophages des punaises des blés

Résumé L'étude du superparasitisme chez les parasites oophages desAelia a été réalisée avec 3 espèces d'Ooencyrtus: O. fecundus Ferr. & Voeg.,O. nigerrimus Ferr. & Voeg., etO. telenomicida Vass. Ces 3 espèces apparaissent comme ayant un pouvoir de discrimination leur permettant d'éviter le superparasitisme lorsqu'elles ont suffisamment d'h?tes à leur disposition. Dans le cas contraire ou lorsque le nombre de femelles dans un même tube de ponte s'accro?t, la tendance au superparasitisme augmente. Le superparasitisme se traduit par une baisse de la fécondité, une diminution de la taille et une modification du taux sexuel de la descendance.

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Summary The study of superparasitism in the oophagous parasites of theAelia spp has been realized with 3Ooencyrtus species:O. fecundus Ferr. & Voeg.,O. nigerrimus Ferr. & Voeg. andO. telenomicida Vass. These 3 species appeared to have a discriminating ability which enable them to avoid superparasitism when the host population at their disposal is sufficient. In the opposite case or, when the number of females increases in the same tube, superparasitism tends to increase. Superparasitism results in a decrease in fecundity as well as in size and the sex-ratio of the offspring.