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.     

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.

     

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     

Les Diastopora (Bryozoaires cyclostomes) néocomiensdu Jura suisse et français

Under the name Diastopora are grouped tubularspecies hitherto assigned to the genera Diastopora and Entalophora. The diameter of the axial canal, a character used to separate the two genera, is partly correlated with the diameter of the stems and often with environmental factors. This character appears too variable; sometimes the stems of one colony would be placed two genera. The affinity of Diastopora with Mesentéripores is proved by the similarity of the three principal types of ovicells. The acknowledgement of three types of ovicells involve the distribution of the species in three groups. Perhaps, this is a first step towards the dismemberment of the genus Diastopora.Six species of Diastopora were found in the Neocomianof the Jura. Two are new: D. alata and D. compacta. The predominance of these species changes with stratigraphical position, paralleling lithofacies. D. tubulosa is dominant in the Lower Valanginian (hard or sandy bottom in agitated water?), but decreases in the Upper Valanginian (chiefly Calcaires à Alectryonia and marls rich in fragments of bivalve shells; shelly, sandy bottom with little mud) where D. alata becomes dominant. Finally, Diastopora with perforated ovicells (D. brunsvicensis, D. canaliculata, D. salevensis appear and replace the previous species during the Upper Valanginian and Lower Hauterivian, with expansion of the grey marl facies (muddy and deeper bottom?).     

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.     

Anticorps anti-spermatozoïdes: techniques de dépistage et interprétation des résultats

Since the first publication on the detection of sperm-agglutinating antibodies in infertile men, multiple assays have been described. The most useful tests are able to detect antibodies bound to the sperm membrane of motile spermatozoa. The immunobeads test (IBT) is considered to be the most advantageous in terms of its sensitivity, the low incidence of false-positive results, and its ability to localize antibodies of different immunoglobulin classes on the sperm surface. The IBT assay can be used in parallel with the mixed antiglobulin reaction (MAR), to detect sperm-associated antibodies in the ejaculates of infertile men, the most rational way to test for antisperm antibodies (ASA) in males. In view of the high level of agreement between the two assays, MAR, the easier of the two, may be used as a first step in the detection of these antibodies. A positive MAR must be confirmed by IBT, as this assay is more specific for the detection of IgA antibodies. The clinical significance of sperm-associated antibodies is usually established according to the proportion of motile spermatozoa coated with immunobeads, its class and its localization on the sperm surface. However, binding of immunobeads does not provide any information about the antigens against which the antibodies are directed. As the functional effects of sperm-associated antibodies may vary as a function of their antigenic specificities, other assays, using purified fertilization related antigens, are necessary to establish, for each individual, the specific impact of the antibodies on the fertilization process. The indirect IBT assay has recently become the most widely used test to detect the various classes of ASA in serum and cervical mucus of infertile women and in the serum and seminal fluid of infertile men, in combination with the direct assay described above. However, in most laboratories, it is performed with only one dilution of the biological fluid tested, usually a low dilution, so that antibody levels of no significance for fertility could be detected. This may explain a recente debate (Human Reprod, 1999) on the significance of ASA as a cause of infertility. At present, and in the absence of standardized assays able to identify the antigens involved in each individual immune reaction, antibody assays, as detected by the IBT assay, in the serum and/or genital secretions of infertile subjects might provide useful clinical guidance.     

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.     

Spermatozoïdes,environnement et prévention

Over the last fivty years, the risk factors for infertility have increased substantially, particularly those due to the environment. Spermatogenesis and spermatozoa can be affected by physical (ionizing radiation microwaves, heat, cryopreservation) or chemical agents (antimitotics drugs, antibiotics, tranquillizers, insecticides, pesticides, industrial solvants, some heavy metals, alcohol, cannabis etc.). Some natural factors, as stress or paternal age (ageing or very youthful age relatively to about thirty) also seems to affect spermatogenesis and, particularly, the age can be joined with the previous ones. On the whole, these factors are able to decrease the male fertility through some changes about the concentration, the motility or the morphology of spermatozoa and so it is possible to describe populations subject to the risk. Moreover, these spermatogenetic changes can lead abnormalities in progeny. For instance, some antimitotic drugs as cyclophosphamide, when administrated to the male rat, lead malformations or functional anomalies as behavioral troubles. The industrial solvents lead a decrease of the birth weight and the cannabis leads an increase of the ante-or post-natal death. Moreover, the change of the paternal spermatogenesis caused by cannabis can be found again in the male progeny. The problem is similar with the lead, the benzodiazepines and the alcohol. Concerning the physical factors, some authors have shown that the children born from radiation exposed fathers presented an increase of the probability of leukemia. In animal, the postimplantation loss is increased when the father is irradiated or subjected to heat before mating. Finally, the paternal ageing is responsible for new dominant autosomic mutations. Moreover, in animal and man, paternal ageing and, in man, very youthful age, also seems responsible for a gradual lowering in the level of progency cerebral functions. On the whole, these data should lead to an preventive attitude which would be more effective before about thirty years of age than after this period.     

Principes de préparation et de congélation des spermatozoïdes testiculaires humains

The advantages and feasibility of human testicular spermatozoa cryoconservation for intracytoplasmic sperm injection (ICSI) have now been clearly demonstrated. However, the freezing protocol is based on empirical knowledge obtained from freezing of ejaculated spermatozoa. Testicular spermatozoa may not be fully mature gametes and may also be retrieved in only limited quantities. Little research has been conducted to determine whether they have the same cryobiological requirements as ejaculated spermatozoa. A better understanding of their cryobiological features and assessment of possible subcellular changes after thawing would help to optimize testicular preparations for cryopreservation (whole biopsies, seminiferous tubules, shredded suspension, single spermatozoa, etc.), freezing-thawing procedure, freezing media, and storage. Finally, there is a growing need for welldefined criteria (nuclear quality, etc.) to evaluate the tolerance of testicular spermatozoa to freezing-thawing procedure for ICSI     

Personnalisation des émotions et cortex médial préfrontal

Functional brain imaging studies in healthy subjects suggest that several regions (prefrontal cortex, amygdala, thalamus, hippocampus, anterior cingulate) have specialized functions for emotional operations. Within these regions, the medial prefrontal cortex (MPFC) is considered to have a general role in emotional processing. Using a memory paradigm with verbal material, we recently demonstrated that the MPFC is specifically involved in self-related processing of emotional stimuli. Study with mood induction also suggest that personality traits may modulate the reactivity of the MPFC to emotional Stressors. Taken together these findings support the hypothesis that the MPFC subserve processes involved in emotion regulation. Dysfunction of the MPFC and related structures (i.e. amygdala) may increase the vulnerability to emotional disorders.     

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.     

Les protéines phosphatases et protéines kinases des plantes supérieures

The recent gain in knowledge concerning enzymes involved in signal transduction pathways is a direct consequence of the considerable advances made in molecular biology. Protein kinases and protein phosphatases, the two major enzymes implicated in post-translational modifications, have been studied in particular. The number of characterized plant genes and/or cDNAs encoding these enzymes is increasing everyday. Since 1991, 26 genes and cDNAs coding for plant protein phosphatases have been isolated and characterized. The huge number of protein kinases (estimated at several thousands) makes it impossible to give an exhaustive list of the genes already identified, but a classification of these enzymes, based on phylogenetic criteria, allows us to appreciate the range of functions this protein family may play in plants.