Etude sur la végétation des dunes et des landes de la bretagne

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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.     

Sur la ségrégation physiologique et la variation des especes

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Contribution à la connaissance des Copépodes de la Région Parisienne

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Contribution a la connaissance des propriétés du virus de la densonucléose

Résumé Le virus de la densonucléose est thermorésistant. Il n'est pas inactivé après traitement avec des solvants de lipides. Aucun pouvoir hémagglutinant n'a été mis en évidence avec des érythrocytes d'espèces variées. Ces propriétés sont comparées à celles desParvovirus.

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Summary The densonucleosis virus is thermoresistant. It is not inactivated after treatment with lipid solvents. Attempts to demonstrate hemagglutination of DNV, using different erythrocytes, were unsuccessful. These properties are compared to those of Parvoviruses.

     

Les hyménoptères parasites de la mouche des olives I. Les chalcidiens de la région méditerranéenne

Summary In this brief work, authors study the five Chalcidids parasites of the olivefly in the mediterranean zone and discuss the systematic point of view. They modify the generic name (Cyrtoptyx, Pnigalio) and show the existence of the new speciesP. mediterraneus; this name substitutes the other nameE. longulus Zett which was wrongly given to theDacus's parasite. A table has been done for the rapid identification of the five species of Chalcidids.

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Riassunto Nel presente breve lavoro, gli AA. riprendono lo studio dei cinque Calcididi parassiti della mosca delle olive nella zona mediterranea, ne discutono il valore dal punto di vista sistematico, ne modificano la denominazione generica (Cyrtoptyx, Pnigalio) e mettono in evidenza l'esistenza della nuova specieP. mediterraneus, il cui nome sostituisce quello diE. longulus Zett., erroneamente attribuito al parassita delDacus. E'stata compilata una tabella per l'identificazione rapida di queste cinque specie di Calcididi.

     

Applications à la conchyliculture des récentes acquisitions sur la biologie des mollusques bivalves

Today, mollusc farming represents the fourth part of the mundial aquaculture production. These results have been permitted by the improvement of farming techniques commercially important but also by advances in the biology of a species. Valuable reproductive studies have been carried out in s.a. hatcheries on triploids and tetraploids animals. Since the last decade, advances in the knowledge of metabolism and growth mechanisms has helped the improvement of the brood stock. Nevertheless, the mundial expansion of bivalve farming increases the outbreak of strong epizooties. Investigations allow a valuable knowledge on the scope of molluscan defence mechanisms against pathogen agents. The results are discussed in relation to a possible selection for bivalve farming.     

Les micrasterias de la région des Trois-Riviéres

Sans résuméLa Pointe-du-Lac, P. Q.