Ecotoxicity of single and mixture of perfluoroalkyl substances (PFOS and PFOA) in soils to the earthworm Aporrectodea caliginosa.

Per and polyfluoroalkyl substances (PFAS) are persistent compounds that are massively used in industry, consumer goods and fire-fighting foams. Soil contamination by PFAS is a major environmental concern, and there is a lack of knowledge on both their ecotoxicological mechanisms and the concentrations that induce adverse effects especially to non-target organisms, particularly in the case of PFAS mixtures. This study contributes to filling these gaps by assessing and modelling the effects of PFAS (in single and in mixtures for PFOS and PFOA at different environmental doses) on juvenile endogeic earthworms of a common species in European soils (Aporrectodea caliginosa) at different levels of biological organization (sub-individual and individual). The results showed for the first time combined strong ecotoxicological effects of PFAS on earthworm survival, integumental integrity, growth, sexual maturity and on genomic stability notably with the induction of DNA breaks associated with no abnormal oxidative DNA-lesion levels. Our results demonstrated significant effects at 0.3 mg kg-1 and additive effects in case of mixtures.

[Preliminary study of p53 and FGFR3 gene mutations in the urine for bladder tumors]. / Étude préliminaire des mutations des gènes p53 et FGFR3 sur le culot urinaire des tumeurs de la vessie.

INTRODUCTION: Two major pathways are described in bladder carcinogenesis: one for invasive or high grade tumors characterized by alteration of the p53 tumor suppressor gene and the other for non-invasive tumors or low grade involving mutations FGFR3. The objective of our study was to validate the research in the urine of mutations in these two genes in patients with a bladder tumor. PATIENTS AND METHODS: In our preliminary study, we investigated 36 patients the FGFR3 and p53 mutations in tumors and urine collected during endoscopic resection. The p53 mutations were sought in FASAY, which allows a functional analysis of the protein P53. The FGFR3 mutations were sought in SNaPshot that searches the eight most frequent mutation points of this gene. RESULTS: For 24 patients (66% of cases), we found at least one of the two mutations in the tumor. This mutation was present in the urine in 15 patients (sensitivity=62.5%). In only one patient, we found a mutation in the urinary sediment that did not exist in the tumor (specificity=91.7%). CONCLUSION: The search for mutations of p53 and FGFR3 in the urine was a simple and non-invasive assay, which seems superior to urinary cytology for the detection of bladder tumors, raising hopes of an interest in this bio-assay for surveillance of bladder tumors and screening risk populations.

Effects of salinity and temperature on the expression of enzymatic biomarkers in Eurytemora affinis (Calanoida, Copepoda).

In order to establish effective enzymatic biomarkers that could provide in situ early warning of contaminant exposure in estuarine ecosystems, the potential effects of the principal abiotic factors (temperature and salinity) were investigated on common biomarkers, the acetylcholinesterase (AChE) and the glutathione S-transferase (GST) in Eurytemora affinis. Short term salinity stress effects simulated during an experimental tide indicated that enzymatic activities of this species are characterized by maximum expression related to an optimal salinity range (between 5 and 15 psu). Moreover, longer time exposure to various salinity tanks confirmed the effects of this factor on both AChE and GST activities. Therefore, optimal AChE activity was measured at 10 psu, while optimal GST activity was measured at 5 psu. Furthermore, significant effects of temperature were also recorded, particularly for AChE expression (slight effects were measured on GST expression) with an optimal condition at 11 degrees C. These experiments indicated a more pronounced effect of salinity over temperature especially on the AChE expression and confirmed the need to standardize sampling procedures in relation with environmental parameters for biomonitoring studies based on enzymatic analyses.

Telomere-length regulation in inter-ecotype crosses of Arabidopsis.

Telomeres, the nucleoprotein complexes at the ends of eukaryotic chromosomes, are maintained at a species-specific equilibrium length. Arabidopsis thaliana is a self-fertilizing plant and different geographical isolates or ecotypes show differing telomere-lengths. We have exploited this telomere-length polymorphism between Arabidopsis ecotypes to investigate the genetic regulation of telomere length by analysing telomere lengths in 16 different inter-ecotype crosses between plants with differing telomere sizes. With two exceptions, the inter-ecotype hybrid plants present a new telomere-length set point, intermediate between that of the two parents. A regulation mechanism thus shortens the longer and lengthens the shorter telomeres.

[Apoptosis of the follicular cells: its implication in ovarian induction protocols]. / L'apoptose des cellules folliculaires: son implication dans les protocoles de stimulation ovarienne.

Atresia, a degenerative process through which many follicles are removed from the grown pool of follicles involves apoptotic changes in the follicular cells. This review analyses the endocrine regulation of apoptotic cell death in ovarian follicle. FSH is the major survival factor for preovulatory follicle but follicle integrity, in vitro, was necessary to its action on granulosa cell. The role of LH is more ambivalent. FSH and LH exert their activity via activation of the cAMP signal. High levels of intracellular cAMP could enhance steroidogenesis and in the same time induce apoptosis in granulosa cells. Moreover, no correlation between steroidogenesis and apoptosis can be established. During ovarian stimulation in IVF protocol, the use of LH, of coasting and of GnRH agonists and antagonists could be deleterious in follicle survival.

Involvement of theca cells and steroids in the regulation of granulosa cell apoptosis in rabbit preovulatory follicles.

Follicular atresia is characterized by a rapid loss of granulosa cells and, to a lesser extent, theca cells, via apoptosis. The aim of this study was to investigate the possible involvement of theca cell secretions in the regulation of apoptosis of rabbit granulosa cells. The annexin-V binding method based on externalization of phosphatidylserine to the outer layer of plasma membrane during apoptosis was used to detect apoptotic granulosa cells in flow cytometry. Regulation of apoptosis of granulosa cells was studied in three different culture systems: (i) isolated cultured granulosa cells, (ii) granulosa cells obtained from cultured preovulatory follicles and (iii) granulosa cells co-cultured with theca cells. The results of this study indicate that: (i) the rate of apoptosis of granulosa cells was significantly reduced when granulosa cells were co-cultured with theca cells or obtained from cultured preovulatory follicles in comparison with isolated cultured granulosa cells; (ii) FSH exerts its anti-apoptotic effect only on granulosa cells issued from cultured preovulatory follicles; (iii) ovarian steroids do not affect the percentage of isolated apoptotic granulosa cells; and (iv) the occurrence of an apoptotic process in rabbit theca cells could be upregulated in vitro by hCG and an analogue of the gonadotrophin second messenger cAMP. The results of this study indicate that in rabbits (i) steroids were ineffective in vitro in protecting isolated granulosa cells against apoptosis in comparison with observations in vivo in rats, and (ii) the presence of theca cells was efficient to reduce granulosa cell apoptosis but not sufficient to allow the anti-apoptotic effect of gonadotrophins observed in cultured follicles.

Hormonal regulation of apoptosis in rabbit granulosa cells in vitro: evaluation by flow cytometric detection of plasma membrane phosphatidylserine externalization.

Annexin V and propidium iodide bivariate analysis and the TUNEL method were used to quantify hormonal regulation of apoptosis in rabbit granulosa cells from preovulatory follicles in vitro. The aim of this study was to analyse comparatively the effects of gonadotrophins and their second messenger in the regulation of granulosa cell apoptosis in (i) cultured isolated granulosa cells and (ii) granulosa cells scraped from cultured follicles. The results showed that increasing doses of FSH had no effect on apoptosis of cultured isolated cells but caused a decrease in the number of apoptotic granulosa cells from preovulatory follicles cultured in serum-free conditions. Unlike FSH, addition of hCG did not modify apoptosis of granulosa cells significantly. In contrast, dibutyryl cAMP had an apoptotic effect in the two cellular models in the presence of serum. Moreover, a biphasic effect of dibutyryl cAMP in isolated granulosa cells was observed with an increase in the incorporation of [(3)H]thymidine into DNA at the lowest dose and an increase in apoptotic cell death at the highest dose. It was concluded that, in rabbits: (i) FSH requires follicle integrity to exert its anti-apoptotic effect in granulosa cells; (ii) dibutyryl cAMP induces a dose-dependent apoptotic effect in granulosa cells cultured alone or obtained from cultured preovulatory follicles; and (iii) cAMP signals induce opposite effects on growth and apoptosis in granulosa cells.