RESUMEN
In this paper we demonstrate a liquid optical switch based on total internal reflection. Two indium tin oxide electrodes are fabricated on the bottom substrate. A conductive liquid (Liquid 1) is placed on one side of the chamber and surrounded by a density-matched silicone oil (Liquid 2). In initial state, when the light beam illuminates the interface of the two liquids, it just meets the conditions of total internal reflection. The light is totally reflected by Liquid 2, and the device shows light-off state. When we apply a voltage to the other side of the indium tin oxide electrode, Liquid 1 stretched towards this side of the substrate and the curvature of the liquid-liquid interface changes. The light beam is refracted by Liquid 1 and the device shows light-on state. So the device can achieve the functions of an optical switch. Because the light beam can be totally reflected by the liquid, the device can attain 100% light intensity attenuation. Our experiments show that the response time from light-on (off) to light-off (on) are 130 and 132 ms, respectively. The proposed optical switch has potential applications in variable optical attenuators, information displays, and light shutters.
RESUMEN
OBJECTIVE: To express the soluble recombinant Schistosoma japonicum SjPP proteins in TN5B1-4 cells. METHODS: The total RNA was extracted from adult worms of Schistosoma japonicum. The whole coding sequence of SjPP gene was synthesized by RT-PCR and cloned into donor plasmid. The recombinant donor pFastBac-SjPP was transformed into E.coli DH10Bac forming Bacmid-SjPP which was transfected into insect cell with cational lipofectin. The fusion protein SjPP was analyzed with SDS-PAGE and Western blotting. RESULTS: The infective recombinant baculovirus Bacmid-SjPP was obtained and SjPP protein was expressed in insect cells. CONCLUSION: The recombinant protein SjPP has been expressed in insect TN5B1-4 cells with proper antigenicity.
Asunto(s)
Baculoviridae/genética , Proteínas del Helminto/biosíntesis , Schistosoma japonicum/genética , Animales , Línea Celular , Clonación Molecular , Escherichia coli/genética , Expresión Génica , Plásmidos , Proteínas Recombinantes/genética , Spodoptera/citología , TransfecciónRESUMEN
Wnt proteins together with their downstream effectors forms a set of important signal pathways. The Wnt signal pathway is important in a wide variety of development processes including cell growth, cell differentiation, cell polarity and apoptosis. Wnt4 is a key regulator of gonadal differentiation in humans and mice, playing a pivotal role in early embryogenesis. With RACE technique based on a EST identified in our lab, a novel gene including a complete open reading frame was cloned and named Sjwnt4 (GenBank accession No. DQ643829). Sequence analyses showed that SjWnt4 had a typical characteristics of Wnt family proteins, sharing 43% similarity to Dugesia japonica and 37% to human Wnt4. The ORF of Sjwnt4 contains 1311 nucleotides, encoding 436 amino acid with 49.6 kD molecular weight. Real-time PCR analysis from the worms of various stages of S. japonicum revealed that the mRNA level of Sjwnt4 is highest in the 19 days schistosomula, followed by 44 days female worms, 14 days schistosomula, 31 days adult worms and 44 days male worms, suggesting a stage-and-gender differential express. The Sjwnt4 cDNA fragment was subcloned into a modified expression vector pGEX-4T-2 and transformed into E. coli BL21 (DE3) cells, and the production of recombinant Sjwnt4 protein fused to a GST tag was analysed. In the presence of IPTG, the 76kD fusion protein was expressed in included bodies. Western-blotting revealed that the fusion protein could be recognized by the rabbit serum specific to Schistosoma japonicum adult worm antigen preparation. The study provides important basis for investigating the regulation mechanism of the Wnt signaling pathway during the development especially gonadal differentiation processes of Schistosoma japonicum.
