Changes in motility, ATP content, morphology and fertilisation capacity during the movement phase of tetraploid Pacific oyster (Crassostrea gigas) sperm.

Changes in sperm features during the movement phase are especially interesting to study in external fertilization species whose sperm duration movement is long because this implies a significant adaptation of moving cells to the external medium. This study describes the changes in tetraploid Pacific oyster sperm characteristics in relation to time post activation. Sperm individually collected on three tetraploid males were activated in seawater. Their features were analysed over a 24h period and compared to a sperm pool collected on three diploid males as a reference. The percentage of motile spermatozoa, the intracellular ATP content, and the fine structure of spermatozoa were studied in relation to time post activation. Furthermore, the fertilisation capacity of sperm individually collected on five diploid males was assessed after 1 and 24h post activation. A forward progressive movement was maintained for at least a 20h duration. Compared to diploid males, the percentage of motile spermatozoa was lower in tetraploid males. The intracellular ATP concentration was higher in spermatozoa from tetraploid males than in spermatozoa from diploid males. A decrease in ATP content was observed in the first 6h post activation and severe alterations were observed in sperm morphology after 24h. Then, a lower fertilisation capacity of sperm from diploid males was observed at the end of the movement phase. The cessation of Pacific oyster sperm motility was unlikely caused by ATP consumption as ATP concentration was still high at the end of sperm movement but rather caused by drastic changes in sperm morphology. Compared to sperm collected on diploid males, the lower quality of sperm from tetraploid males was emphasized by a shorter movement duration and deeper morphological alterations at the end of the movement phase.

Use of accelerating solvent extraction for detecting non-steroidal anti-inflammatory drugs in horse feces.

Feces are a possible medium to be used for horse doping control. Efficient methods for detecting drugs in feces collected from various animals are routinely applied in institutes of food safety in Belgium. We have already tested whether they are applicable to horse feces. In this report, accelerated solvent extraction (ASE), an efficient method for extracting compounds from solid material, has been tested. ASE has been used to replace the diethyl ether liquid-liquid extraction step present in the method initially set up. This technique has been optimized for detecting several non-steroidal anti-inflammatory drugs (NSAIDs) in horse feces. Extraction recovery and limit of detection have been determined for several NSAIDs, such as meclofenamic acid, flunixin, vedaprofen, celecoxib, carprofen, diclofenac, and ketoprofen. The method has been successfully applied to meclofenamic acid, flunixin, and phenylbutazone post-administration feces samples, and the main metabolites identified in urine were also detected in feces. In the case of meclofenamic acid, the detection profile in feces presented in this report is in accordance with our previous finding in feces obtained with the original method. The use of ASE decreases the time necessary for sample preparation. This method is applicable on a large scale, which is useful for horse doping control.

Variations in food intake of Pecten maximus (L.) from the Bay of Brest (France): influence of environmental factors and phytoplankton species composition.

Previous studies carried out in the bay of Brest on daily shell growth of Pecten maximus have demonstrated that temperature is a major control on daily shell growth in contrast to food supply. However, repeated events of slow growth have been observed during diatom and dinoflagellate blooms. The aim of this study was to determine how fluctuations in environmental parameters influence P. maximus food intake and daily shell growth rate. In 1995, P. maximus food intake and growth were highest when Cerataulina pelagica (diatom) blooms occurred and lowest during Gymnodinium cf. nagasakiense (dinoflagellate) blooms. During blooms of other diatom species, P. maximus food intake and growth were high when the algal concentration did not exceed a critical threshold, dependent upon the dominant species and sedimentation rate of diatoms. These results demonstrate that the morphological and physiological features of phytoplankton bloom species strongly affect benthic microphytophagy, a component of benthic-pelagic coupling.

The amylase-secreting cells of the stomach of the scallop, Pecten maximus: ultrastructural, immunohistochemical and immunocytochemical characterizations.

(1) alpha-amylase was extracted and purified from the stomach/digestive gland complex of the scallop Pecten maximus and an anti-serum was induced against the purified amylase by rabbit immunization. (2) The anti scallop amylase was used to localize the amylase-secreting cells in the stomach of Pecten maximus by immunofluorescence and immunogold labelling. The amylase-secreting cells are glandular cells particularly numerous in the main sorting area of the stomach. Their secretory granules were found strongly positive for anti-amylase. Three types of glandular cells were observed, actually corresponding to the three stages of the glandular-cell activity, synthesis, secretion and excretion. (3) The synthesizing cell shows the characteristic features of a protein-synthesizing cell: a conspicuous nucleolus and abundant granular endoplasmic reticulum. In the secretory cell, the secretory granules are formed by the Golgi apparatus and accumulate in the apical part of the cell. The secretory cell is filled with two types of secretory granules which are released in the stomach lumen by apocrine excretion. (4) The present study brings the first demonstration of the synthesis and extracellular release of amylase by glandular cells of the stomach epithelium of a bivalve.

[Acanthamoeba keratitis. Epidemiologic and parasitologic study]. / Kératite amibienne á Acanthamoeba. Etude épidémiologique et parasitologique.

The amebic keratitis with Acanthamoeba are until now rare, but however increasing as their diagnosis is better, and the contact lens wearers more numerous. The authors present the clinical and parasitological features of cases they did diagnose since 1986. In the immunological sphere, the T4 lymphocytes were 20% less than the normal for the first patient, and the third one had a very low level of immunoglobulins A. In the evolution sphere, the first one did received a keratoplasty; the second one has been successfully treated with propamidine isethionate; for the third one, the treatment with propamidine isethionate was nonuseful and a keratoplasty which was finally performed did show off numerous amebic cysts. In the parasitologic sphere, Acanthamoeba polyphaga was isolated from the first case, Acanthamoeba quina from the second one and Acanthamoeba lugdunensis from the last one. These last two cases are the first which did permit to isolate these amoebae, morphologically near to the first species.