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

Вплив товщини плівки на властивості тонких плівок Co-ZnO, отриманих золь-гель методом

Тонкі плівки ZnO, леговані 1 мас. % Co (CZO) різної товщини (3, 5 і 7 шарів, що відповідають товщині 403, 545 і 725 нм) наносяться золь-гель методом на скляні підкладки технікою нанесення покриттів зануренням. Дегідрат ацетату цинку, ацетат кобальту, 2-метоксиетанол і етаноламін використовуються відповідно як первинні матеріали, розчинник і стабілізатор. Термічно відпалені плівки охарактеризовано для вивчення структури, морфології поверхні, електричних та оптичних властивостей. Дифракція рентгенівських променів (XRD) показує, що ці плівки мають полікристалічну гексагональну структуру (структура вюрциту з просторовою групою P63mc), володіють напругою стиску та мають переважну орієнтацію вздовж площини (002). Відзначимо, що при збільшенні товщини розмір частинок зменшується. Морфологію поверхні отриманих тонких плівок CZO досліджують за допомогою атомно-силової мікроскопії (АFМ). Вона виявляє появу однорідної стовпчастої структури та показує, що розмір частинок і середньоквадратична шорсткість CZO збільшуються зі збільшенням товщини. УФ-видима спектроскопія показує (у видимій області) пропускання від 75 до 86 % для всіх плівок, сильне поглинання (в УФ-області) і зменшення оптичної забороненої зони. Крім того, товщина впливає на ближній край смуги (NBE) і видиме випромінювання, що виявляється фотолюмінесценцією. Електропровідність зразка з довжиною хвилі 725 нм становить 4,43 (Ом∙см) – 1.1 wt. % Co-doped ZnO (CZO) thin films of varying thicknesses (3, 5 and 7 layers, which correspond to 403, 545 and 725 nm as thickness) are deposited using the sol-gel method onto glass substrates by dip coating technique. Zinc acetate dehydrate, cobalt acetate, 2-methoxyethanol and ethanolamine are used as primary materials, solvent and stabilizer, respectively. The thermally annealed films are characterized to study the structural, surface morphology, electrical and optical properties. X-ray diffraction (XRD) shows that these films have a polycrystalline hexagonal structure (wurtzite structure with space group P63mc), possessing compressive stress and presenting a preferred orientation along the (002) plane. We note that the particle size increases when the thickness increases. The surface morphology of the prepared CZO thin films is investigated by atomic force microscopy (AFM). It reveals the emergence of a uniform columnar structure and shows that the particle size and the root mean square (RMS) of CZO increase with increasing thickness. UV-visible spectroscopy shows (in the visible region) a transmittance between 75 and 86 % for all the films, strong absorption (in the UV region) and a decrease in the optical band gap. Moreover, the near band edge (NBE) and visible emissions detected by photoluminescence are affected by the thickness. The electrical conductivity of the sample with 725 nm is found to be 4.43 (Ω∙cm) – 1

Investigation of differences in sensitivity between 3 strains of Daphnia magna (crustacean Cladocera) exposed to malathion (organophosphorous pesticide)

International audienceAcute and chronic ecotoxic effects of organophosphorous insecticide malathion (Fyfanon 50 EC 500g L-1) were investigated on three strains of Daphnia magna. The nominal effective concentrations immobilizing 50% (EC50) of Daphnia after 24 and 48h were 0.53 and 0.36 mu g L-1, 0.70 and 0.44 mu g L-1, and 0.75 and 0.46 mu g L-1 for the strains 1, 2, and 3 respectively. There was an increase in malathion ecotoxicity with time of exposure as confirmed by chronic studies. In fact, after 21days of exposure, significant effects on survival (lowest observed effect concentration or LOECs) were recorded at malathion concentrations of 22, 220 and 230ng L-1 for strains 1, 2 and 3 respectively. Other endpoints were also examined, including reproduction (with different parameters), body length and embryo toxicity. ICs10 and ICs20 were calculated for these different parameters. ICs10 ranged from 4.7 to more than 220ng L-1 for the three tested strains. The most sensitive parameter was the number of neonates per adult (ICs10 = 4.7 and 10.8ng L-1 for strains 1 and 2 respectively) or the number of broods (IC10 = 10ng L-1 for strain 3). Moreover, an increase in embryo development abnormalities was observed at the two highest tested malathion concentrations. Abnormalities comprised undeveloped second antennae, curved or unextended shell spines, and curved post-abdomen spines in live neonates. Results suggest that malathion could act as an endocrine disruptor in D. magna as it interferes with development. It also induces a significant decrease in acetylcholinesterase (AChE) activities for the three strains. Both strains 2 and 3 seemed more sensitive (LOECs = 60ng L-1) than strain 1 (LOEC = 120ng L-1). Our results suggest that the AChE activity response can also be used as a biomarker of inter-strain (or inter-clonal) susceptibility (i.e. strain (or clone)-specific response)