Reproductive Cycle and Plasma Levels of Sex Steroids in Female Eurasian Perch Perca Fluviatilis

From April 1995 to April 1996, the annual reproductive cycle of the Eurasian perch Perca fluviatilis was studied at the Fishfarming Lindre Center (Moselle, France). At monthly intervals (at intervals of 10 days during the periovulatory period), 5 females were caught and dissected. From sampled organs, the gonado-, hepato- and viscerosomatic indexes (GSI, HSI, VSI) were calculated, oocyte diameters (OD) and the plasma levels of testosterone (T), 17P-estradiol (E2), 17,20P-dihydroxy-4-pregnen-3-one (17,2Op-P) and protein-phosphorus (PPP) were measured. After the sexual resting period observed from May to August (GSI \u3c 1 %, OD \u3c 200 urn, VSI = 4-6 %), oogenesis began in September when the water temperature decreased from 26.4 to 14.1 “C. The GSI increased progressively until mid March (15 %), then rapidly until spawning (25 %, OD = 850 urn) which occurred in April (14- 15 “C). The plasma levels of T, E,, 17,2Op-P and PPP were low during the sexual resting period. E, and PPP levels increased significantly at the onset of the oogenesis in September, then the E, level raised abruptly in November (3-4 ng mL-‘). In December, the T level increased rapidly to 15-20 ng . mL-’ The testosterone, E, and PPP levels remained very high until spawning, indicating the existence of active vitellogenesis. The highest HSI (2.1-2.2 %) recorded in winter confirmed this. During the periovulatory period, a peak of E, (4 ng . mL-‘) appeared, whereas T level diminished. In this study, 17,2Op-P levels remained low (0.2-0.6 ng mL-‘) and relatively constant. No 17,2Op-P peak was observed during the periovulatory period. Sampling at 10 day intervals was probably inadequate to specify the hormonal variations related to the final oocyte maturation and the ovulation. 0 Ifremer-Elsevier, Paris

Reproductive Cycle and Plasma Sex Steroid Profiles in Male Eurasian Perch Perca Fluviatilis

From April 1995 to April 1996, the annual reproductive cycle of male Eurasian perch Perca fluviatilis was studied at the Lindre Center (Moselle, France). At monthly intervals, five males (mean body weight of 133 ± 43 g and total length of 175 ± 9 mm) were caught. From sampled organs, the gonadosomatic (GSI), hepatosomatic (HSI) and viscerosomatic indexes (VSI) were calculated and plasma testosterone (T) and 11-ketotestosterone (11KT) levels were measured. After the spawning period in mid-April, GSI and HSI dropped and VSI increased to 3.8 ± 0.1 %. In September, GSI reached its maximum (8.5 ± 1.8 %). At this time, spermatocytes, spermatids and spermatozoa were abundant, whereas in June only spermatogonia were observed. During winter, GSI was stable at approximately 5 %, HSI reached its maximum (1.9 ± 0.3 %) and VSI was low (2.6 ± 0.2 %). From April to November 1995, plasma T and 11KT concentrations were low (\u3c 0.5 ng·mL–1). Plasma T levels increased significantly in December and reached peak levels (12.3 ± 2.1 ng·mL–1) in January, then decreased in February and increased again until spawning in April (6.8 ± 2.1 ng·mL–1). This second elevation could be related to the beginning of a new spermatogenic cycle. Plasma levels of 11KT increased significantly from October to February 1996 (4.9 ± 1.1 ng·mL–1). From February to the spawning period (April 1996), plasma 11KT decreased significantly, but values were significantly higher than those measured in fall. Males were spermiating from January to spawning in April. © 2000 Ifremer/Cnrs/Inra/Ird/Cemagref/Éditions scientifiques et médicales Elsevier SA

Preparedness actions towards seismic risk mitigation for the general public in Martinique, French Lesser Antilles: a mid-term appraisal

International audienceMartinique is a French island in the Lesser Antilles, with a high seismic hazard. In 2006, Martinican stakeholders involved in seismic safety formed the "Réplik" working group ("Aftershock" in French), the first of its kind in this region. This paper addresses a mid-term appraisal of the first seismic awareness campaign organized by Réplik from 2006 to 2011, and how it has modified, or not, local earthquake and tsunami preparedness. Despite efforts from Réplik to assess its efficiency through surveys, a growing gap is noted between the observed awareness and the actual preparedness of the public. As usual, gender, age, educational level, then boredom and saturation contribute to this discrepancy; strong cultural items may also influence the perception of actions. To remain efficient and respond to public's expectations, Réplik must redirect its actions towards a cultural congruence of information: consideration of religion and local beliefs, comprehensive messages on TV and radio, use of Creole language, participatory experiences and drills, with a little bit of science. So that, the Réplik stakeholders can hope to increase Martinicans' involvement into the preparedness process, to cope quickly with a strong earthquake and this know-how can be shared with other seismically active islands in the Caribbean

Reproductive cycle and plasma levels of sex steroids in female Eurasian perch

From April 1995 to April 1996, the annual reproductive cycle of the Eurasian perch Perca fluviatilis was studied at the Fishfarming Lindre Center (Moselle, France). At monthly intervals (at intervals of 10 days during the periovulatory period), 5 females were caught and dissected. From sampled organs, the gonado-, hepato- and viscerosomatic indexes (GSI, HSI, VSI) were calculated, oocyte diameters (OD) and the plasma levels of testosterone (T), 17β-estradiol (E2), 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) and protein-phosphorus (PPP) were measured. After the sexual resting period observed from May to August (GSI < 1 %, OD < 200 μm, VSI = 4-6 %), oogenesis began in September when the water temperature decreased from 26.4 to 14.1 °C. The GSI increased progressively until mid March (15 %), then rapidly until spawning (25 %, OD = 850 μm) which occurred in April (14-15 °C). The plasma levels of T, E2, 17,20β-P and PPP were low during the sexual resting period. E2 and PPP levels increased significantly at the onset of the oogenesis in September, then the E2 level raised abruptly in November (3-4 ng · mL−1). In December, the T level increased rapidly to 15-20 ng · mL−1. The testosterone, E2 and PPP levels remained very high until spawning, indicating the existence of active vitellogenesis. The highest HSI (2.1-2.2 %) recorded in winter confirmed this. During the periovulatory period, a peak of E2 (4 ng · mL−1) appeared, whereas T level diminished. In this study, 17,20β-P levels remained low (0.2-0.6 ng · mL−1) and relatively constant. No 17,20β-P peak was observed during the periovulatory period. Sampling at 10 day intervals was probably inadequate to specify the hormonal variations related to the final oocyte maturation and the ovulation

Reproductive cycle and plasma levels of steroids in male Eurasian perch

From April 1995 to April 1996, the annual reproductive cycle of male Eurasian perch Perca fluviatilis was studied at the Lindre Center (Moselle, France). At monthly intervals, five males (mean body weight of 133 ± 43 g and total length of 175 ± 9 mm) were caught. From sampled organs, the gonadosomatic (GSI), hepatosomatic (HSI) and viscerosomatic indexes (VSI) were calculated and plasma testosterone (T) and 11-ketotestosterone (11KT) levels were measured. After the spawning period in mid-April, GSI and HSI dropped and VSI increased to 3.8 ± 0.1 %. In September, GSI reached its maximum (8.5 ± 1.8 %). At this time, spermatocytes, spermatids and spermatozoa were abundant, whereas in June only spermatogonia were observed. During winter, GSI was stable at approximately 5 %, HSI reached its maximum (1.9 ± 0.3 %) and VSI was low (2.6 ± 0.2 %). From April to November 1995, plasma T and 11KT concentrations were low (< 0.5 ng·mL–1). Plasma T levels increased significantly in December and reached peak levels (12.3 ± 2.1 ng·mL–1) in January, then decreased in February and increased again until spawning in April (6.8 ± 2.1 ng·mL–1). This second elevation could be related to the beginning of a new spermatogenic cycle. Plasma levels of 11KT increased significantly from October to February 1996 (4.9 ± 1.1 ng·mL–1). From February to the spawning period (April 1996), plasma 11KT decreased significantly, but values were significantly higher than those measured in fall. Males were spermiating from January to spawning in April

Le Saulnois : au pays du sel et de la Seille / textes de Bruno Capdeville, Daniel Manzi, Roger Richard ; photogr. de Daniel Manzi

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Silica-based fibers with axially aligned mesopores from chitin self-assembly and sol-gel chemistry

International audiencePolysaccharide nanorods (chitin, cellulose) can be used as colloidal templates to form silica-based mesoporous materials by combining self-assembly and sol-gel chemistry. Chitin nanorods are chosen here for their self-assembly properties, facile preparation from natural resources, and because of the complexing properties of the free amino groups at their surface in view of further functionalization. Electrospinning of ethanolic co-suspensions, containing the chitin nanorods as pore templates, siloxane oligomers as silica precursors and polyvinylpyrrolidone (PVP) as spinning polymer, allows for forming mats of hybrid organic-inorganic fibers with diameters in the 200-300 nm range. The relative proportions of each component can be adjusted to meet specific characteristics (e.g. micro-/mesoporosity ratio). After calcination, the fibers present an open porosity studied by TEM and N2 volumetry. Elongated mesopores (100-200 nm long, 2-4 nm wide) are created by individual chitin monocrystals forming the nanorods. They are highly oriented along the fibers' axes with orientational order parameters P2 > 0.95 for volume chitin contents chitin* ≥ 0.2. Additional microporosity is provided by the removal of the spinning polymer, PVP. Complementary viscosity measurements on the initial cosuspensions allow discussing the interactions between colloids and their possible impact on the materials' textures observed. The introduction of a monomeric Ti 4+ precursor in the co-suspensions leads to isolated and tetrahedral Ti units, distributed in the calcined porous silica fibers and possibly close to the pores surface. In addition, preliminary investigations on processing the fibers with a Zn xanthate as ZnS precursor leads to carbonized fibers with nanoparticles and a Zn/S molar ratio close to 1

Translocation and insecticidal activity of Bacillus thuringiensis living inside of plants

The major biological pesticide for the control of insect infestations of crops, Bacillus thuringiensis was found to be present naturally within cotton plants from fields that had never been treated with commercial formulations of this bacterium. The ability of B. thuringiensis to colonize plants as an endophyte was further established by the introduction of a strain marked by production of green fluorescent protein (GFP). After inoculation of this preparation close to the roots of cotton and cabbage seedlings, GFP-marked bacteria could be re-isolated from all parts of the plant, having entered the roots and migrated through the xylem. Leaves taken from the treated plants were able to cause toxicity when fed to the Lepidoptera Spodoptera frugiperda (cotton) and Plutella xylostella (cabbage). These results open up new horizons for understanding the natural ecology and evolution of B. thuringiensis and use of B. thuringiensis in insect control