Premier inventaire faunistique des Chironomidés (Diptera : Chironomidae) des eaux courantes de Tunisie

Pour la première fois, une liste faunistique de 81 taxa de Chironomidés - 63 identifiés à l'espèce - récoltés par dérive dans 23 oueds du Nord, 2 oueds et 5 oasis du Sud de la Tunisie est présentée. La faune est à dominante paléarctique (55 espèces : 87,3 %). Les 12,7 % restants (8 espèces) sont des éléments de la faune méditerranéenne (3), nord-africaine (2), afrotropicale-ouest paléarctique (2), panpaléotropicale (1). De nouvelles récoltes d'imagos et nymphes [math] matures sont nécessaires pour confirmer l'apparente nouveauté spécifique de 5 types d'exuvies nymphales appartenant aux genres Larsia, Parakiefferiella, Paratanytarsus, Tanytarsus, Virgatanytarsus. 170 espèces de Chironomidés sont à présent recensées d'Afrique du Nord

Acoustic identification of the elastic properties of porous and nonporous superconducting materials DyBa 2-X Sr X Cu 3 O 7-δ

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Effects of deltamethrin (pyrethroid insecticide) on growth, reproduction, embryonic development and sex differentiation in two strains of Daphnia magna (Crustacea, Cladocera)

International audienceAcute and different chronic ecotoxic effects of deltamethrin have been investigated on two strains (coming from two different laboratories) of Daphnia magna. The effective concentrations immobilizing 50% of daphnids (EC(50)s) after 24 h and 48 h were 9.40 and 032 mu g L-1, 8.86 and 0.63 mu g L-1 for first strain (strain 1) and second strain (strain 2), respectively. Thus, there was an increase of deltamethrin ecotoxicity with time of exposure as confirmed by chronic studies. After 21 days of exposure to deltamethrin, daphnids have showed significant effects on survival at deltamethrin concentrations of 0.16 mu g L-1 and 031 mu g L-1 for strains 1 and 2, respectively. Eleven other endpoints were examined: body length, population growth rate and various reproductive parameters (days to first brood, number of broods, number of cumulative molts and number of neonates), embryotoxicity and appearance of males. IC10 values related to the number of juveniles per live adult were 11 and 46 ng L-1 for strains 1 and 2, respectively. Furthermore, an increase in embryo deformities was observed at the highest concentrations tested for both strains. Following deltamethrin exposure, undeveloped second antennae, curved or unextended shell spines, and curved post abdomen spines were observed in live neonates. The production of male juveniles was only registered with strain 1 at 0.16 mu g L-1. Results suggest that deltamethrin could act as an endocrine disruptor in D. magna as it interferes with sex determination and development abnormality but there is a difference in sensitivity between the two tested strains

Production and characterization of a fusion form of hepatitis E virus tORF2 capsid protein in Escherichia coli

Hepatitis E virus (HEV) is a nonenveloped virus causing an emerging zoonotic disease posing a severe threat to the public health in the world, especially to pregnant women. In this study, a truncated form (aa 368–606) of the open reading frame 2 of the capsid protein (tORF2-HEV), a major structural protein of HEV, was expressed in Escherichia coli. This work characterizes for the first time, the fused Glutathione-S-Transferase-tagged tORF2 (GST-tORF2) and tORF2-HEV forms in E. coli. The fusion protein was purified by affinity chromatography with a purity higher than 90% and to yield about 27% after thrombin digestion. The purified GST-tORF2 protein was then characterized by western blot, using anti-GST antibodies, and CD spectroscopy. The GST-tORF2 and tORF2-HEV proteins were shown to be efficient to develop an ELISA test to detect anti-HEV IgG in mice sera immunized with a recombinant full length ORF2 protein. Sera showed a significant increase of the absorbance signal at 450 nm, in plate wells coated with a quantity of 0.5, 1 and 2 µg of proteins. ELISA plates coated with the purified GST-tORF2 and tORF2-HEV showed similar response when compared to the HEV ELISA where total insect cell lysate, infected with the recombinant baculovirus expressing full ORF2, was used as positive control