Nitrite réductase des Saccharomyces (groupe Torulaspora) et des Debaryomyces. implications systématiques

Intracellular nitrite reductase was found in some species of Saccharomyces (Torulaspora group of Van der Walt 1970) and all Debaryomyces (excepted D. castelli and D. coudertii. The taxonomical relationship between the 2 groupes are discussed.

     

Contribution a l'étude des levures des chais- taxonomie,répartition des levures

Résumé Les populations levuriennes de deux chais de Bourgogne sont étudiées sur deux années d'un point de vue taxonomique et biologique. 122 souches se rapportant à 26 espèces, ont été isolées à partir de la voûte et du sol de la cave, sur les madriers supportant les tonneaux, dans la cuve, sur le pressoir et sur les tonneaux. En dehors d'un certain nombre d'espèces classiques dans ce type d'habitat, telles que Saccharomyces cerevisiae, Pichia membranaefaciens, Hansenula anomala et Kloeckera apiculata, nous avons pu mettre en évidence notamment: Debaryomyces hansenii, Torulopsis Candida, Saccharomyces italicus, ainsi qu'un certain nombre d'espèces appartenant aux genres Pichia, Candida et Trichosporon. La répartition qualitative et quantitative des espèces est également étudiée.

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The yeast populations of two burgundy cellars were studied during two years from a taxonomical and biological point of view. 122 strains distributed among 26 species have been isolated from the vault and ground of the cellar, on the planks supporting the barrels, in the tank, on the winepress and on the barrels. Apart from a number of standard species in this type of habitat such Saccharomy cescerevisiae, Pichia membranaefaciens, Hansenula anomala, Kloeckera apiculata we have encountered the more rare Debaryomyces hansenii, Torulopsis Candida, Saccharomyces italicus as also species of the genus Pichia, Candida, and Trichosporon.

     

Données récentes sur la maturation des spermatozoïdes dans l'épididyme humain

Au cours de leur transit épididymaire, les spermatozo?des rencontrent un environnement varié, au regard des protéines avec lesquelles ils rentrent en contract. Dans la partie proximale de l'épididyme, ils sont soumis à l'action d'enzymes, et exposés à des protéines susceptibles de modifier les membranes. Dans la partie moyenne prédomine une autre catégorie de protéines et d'enzymes; celles associées au transport de stérols pourraient modifier les membranes spermatiques afin de permettre l'ancrage de protéines de liaison à la zone pellucide: P 34H et CD52. Dans la partie distale les spermatozo?des rencontrent des activités croissantes d'enzymes lytiques, des protéines impliquées à la fois dans la liaison à la zone pellucidé et la fusion ovocytaire, l'antigène de maturation CD 52, une activité anti-microbienne, et enfin des agents décapacitants qui facilitent leur survie avant l'éjaculation. L'adhérence des protéines aux différents domaines membranaires (comme la région antérieure ou le segment équatorial de l'acrosome) peut dépendre de la nature de la protéine, de la composition lipidique de la région membranaire concernée, et de l'environnement ionique dans la lumière épididymaire. La localisation des protéines sur le spermatozo?de, qu'il soit à acrosome intact (membrane acrosomique) ou acrosome-réagi (segment équatorial) pourra dicter leur r?le, concernant par exemple la fixation à la zona (P 34H), ou la liaison à l'ovocyte (gp 20). Les protéines comme les membranes peuvent être modifiées durant le transit épididymaire par des enzymes qui peuvent ajouter ou retirer des sucres et des peptides de la surface spermatique.     

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.     

Utilisation des spermatozoïdes testiculaires en ICSI. Intérêt de la culture in vitro. Revue de la littérature

The number of ICSI cycles performed with testicular spermatozoa has increased dramatically over recent years. However, one of the technical limitations of this approach concerns the extremely reduced motility of testicular spermatozoa. However, increased sperm motility was observed after incubating testicular samples for several hours. Therefore, in order to improve ICSI success rates, several authors have tested the effect of previous in vitro culture. We present a review of the literature on this subject. In vitro culture does not appear to be very useful in cases of obstructive azoospermia, as, apart from possible sperm “maturation” during this culture phase, a high proportion of motile spermatozoa is usually already observed prior to in vitro culture. The benefits of in vitro culture appear to be greater in the case of non-obstructive azoospermia, as when spermatozoa are present on the biopsy, they are usually immobile. However, discordant results have been published: after in vitro culture, spermatozoa have been reported to be either motile or mostly dead. Regardless of the type of azoospermia, the best results are obtained after 3–4 days of in vitro culture. Addition of recombinant FSH to the culture medium also appears to be effective. Cryopreservation of testicular biopsies may also be associated with in vitro culture and the in vitro culture/freezing sequence appears to give better results than the freezing/in vitro culture sequence. Very few studies have reported the results of ICSI using frozen in vitro cultured spermatozoa, as most published studies concern fresh spermatozoa, used after 1–2 days of in vitro culture with satisfactory fertilization and pregnancy rates. In vitro culture of testicular spermatozoa may therefore constitute an interesting research approach to improve the results of ICSI when the number of spermatozoa and/or motility are very low. In addition, in vitro culture of testicular spermatozoa appears to be a good tool to study the mechanisms of acquisition of motility, which are still poorly understood.     

Classification des stades de sommeil par des réseaux de neurones artificiels hiérarchiques

The goal of our work is to provide an automatic analysis and decision tool for sleep stages classification based on an artificial neural networks (ANN). The first difficulty lies in choosing the physiological signals representation and in particular the electroencephalogram (EEG). Once the representation adopted, the next step is to design the optimal neural network determined by a learning and validation process of data from a set of sleep records. We studied several configurations of conventional ANN giving results varying from 62 to 71 %, then we proposed a new hierarchical configuration, which gives a rate of 74 % correct classification for six stages. These results lead us to further explore this issue at the representation and design of ANNs to improve the performance of our tool.     

Les remplissages sédimentaires des coquilles de céphalopodes triasiques. Mécanismes et intérêt paléoécologique

Experiments have been carried out in laboratory onplastic cephalopod models in order to study most aspects of sedimentary shell filling of Ceratites and Nautilus from the German Upper Muschelkalk. In most cases the shells had a horizontal position when being filled by the sediment. The exception of filling in upright position has been observed mainly for Ceratites nodosus nodosus (Bruguière, 1792), Acanthoceratites spinosus (Philippi, 1901) except the species A. spinosus penndorfi (Rothe, 1955), Acanthoceratites evolutus (Philippi, 1901) and the nautilus Germanonautilus bidorsatus (Schlotheim, 1804); it is due to the width of their shells. In no case the sediment filling of cephalopod shells gives information about the depth of the depositional environment. On the other hand it is a good indicator of the waving occurring on the sea floor and the reworking of the sediment.     

Fissidens monguilloni Thér. in England

Abstract

The 1996 Chagos Expedition provided an opportunity to study the archipelago's bryophyte flora: 25 of the 55 islands were ecologically investigated, some in more detail than others, and lists and representative collections of mosses, hepatics and other cryptogamic plants were assembled for many of them. Although the islands have a low biodiversity for most of these groups, as would be expected in terms of their relatively young age, remoteness and small terrestrial surface areas, those organisms that are present are often found in abundance and play significant ecological roles. Where the status of taxa on islands has been determined, there appears to be a good correlation between bryophyte biodiversity and island size. Epiphytic bryophytes were not host specific and no epiphyllous species was observed. Biogeographic details are provided, where possible, for the 19 taxa recorded, of which four are new to the Indian Ocean and seven are new to the Chagos Archipelago. A new taxon, Cololejeunea planissima var. chagosensis Pócs var. nov. is described, and notes and illustrations of a probably new Lejeunea species are provided.     

Hypoglycémie spontanée et insuffisance rénale chronique.

Although glucose intolerance occurs as a consequence of chronic renal failure, improvement of a diabetic state by deterioration of renal function is a well known phenomenon. Recently occasional cases of spontaneous hypoglycemia in patients with chronic renal failure have been reported; two such cases and the results of metabolic studies are described in this paper. Pituitary, thyroid and adrenal function appeared to be normal. The results of an oral glucose tolerance test were normal; an appropriate insulin response was demonstrated in one patient, and a slightly elevated basal insulin value with a delayed insulin response to oral administration of glucose was demonstrated in the other. An insulin tolerance test did not support the hypothesis of increased insulin sensitivity as a factor, and the growth hormone response to hypoglycemia was normal. An intravenous glucagon test caused a subnormal increase in plasma glucose concentration, and the intravenous administration of tolbutamide produced hypoglycemia without an increase insulin sensitivity as a factor, and the growth hormone response to hypoglycemia was normal. An intravenous glucagon test caused a subnormal increase in plasma glucose concnetration, and the intravenous administration of tolbutamide produced hypoglycemia without an increase in insulin values. The plasma alanine concentration was low and the proinsulin/insulin ratio was increased. The origin of this hypoglycemia is not clear but is probably multifactorial. However, low hepatic glycogen stores and inadequate gluconeogenesis due to substrate deficiency seem to be involved.     

Influence des parasites oophages sur la régulation des populations deCassida deflorata Suff

Summary The layings ofCassida deflorata Suffr. are parasited in southern France byMymaridae (Anaphoidea sp. andFulmekiella ovata soyka),Trichogrammatidae (Monorthochaeta nigra Blood.) andEulophidae (Foersterella flavipes Foerst. andTetrastichus rhosaces Walk.). In the Alpes-Maritimes, two successive generations ofMymaridae andTrichogrammatidae seem to attack the layings ofC. deflorata. In Corsica, parasitism byMymaridae andF. flavipes is very frequent and may be the essential regulating factor of the populations ofCassida. In the other regions that have been studied, although the large number ofCassida imagos appearing in spring show that mortality during the aestivation and hibernation is not the primary factor, it does not seem that the limitation of the populations is essentially caused by the activity of oophagous insects.      

Psychothérapie des cas difficiles. Perspectives phénoménologiques

The author provides a brief overview of clinical anthropology. To achieve better understanding of clinical anthropology, it is very important to grasp its close relationship with the development of phenomenology, most notably existential analysis. This paper mainly references L. Binswanger, S. Freud, V. von Weizsäcker and J. Schotte, arguing that the anthropological perspective is up to date in the psychotherapy of difficult cases. Four fields of application and a clinical case of a psychotic patient’s replacement of medications by psychotherapy after 30 years of use show how the anthropological perspective can create a new way of looking at pathology, help achieve a better relationship with the patient and revitalise the representation of what we call a clinical fact.