The P1 protein of wheat yellow mosaic virus exerts RNA silencing suppression activity to facilitate virus infection in wheat plants.

Wheat yellow mosaic virus (WYMV) causes severe wheat viral disease in Asia. However, the viral suppressor of RNA silencing (VSR) encoded by WYMV has not been identified. Here, the P1 protein encoded by WYMV RNA2 was shown to suppress RNA silencing in Nicotiana benthamiana. Mutagenesis assays revealed that the alanine substitution mutant G175A of P1 abolished VSR activity and mutant Y10A VSR activity remained only in younger leaves. P1, but not G175A, interacted with gene silencing-related protein, N. benthamiana calmodulin-like protein (NbCaM), and calmodulin-binding transcription activator 3 (NbCAMTA3), and Y10A interacted with NbCAMTA3 only. Competitive Bimolecular fluorescence complementation and co-immunoprecipitation assays showed that the ability of P1 disturbing the interaction between NbCaM and NbCAMTA3 was stronger than Y10A, Y10A was stronger than G175A. In vitro transcript inoculation of infectious WYMV clones further demonstrated that VSR-defective mutants G175A and Y10A reduced WYMV infection in wheat (Triticum aestivum L.), G175A had a more significant effect on virus accumulation in upper leaves of wheat than Y10A. Moreover, RNA silencing, temperature, and autophagy have significant effects on the accumulation of P1 in N. benthamiana. Taken together, WYMV P1 acts as VSR by interfering with calmodulin-associated antiviral RNAi defense to facilitate virus infection in wheat, which has provided clear insights into the function of P1 in the process of WYMV infection.

Measurement-Device-Independent Quantum Key Distribution Based on Decoherence-Free Subspaces with Logical Bell State Analyzer.

Measurement-device-independent quantum key distribution (MDI-QKD) enables two legitimate users to generate shared information-theoretic secure keys with immunity to all detector side attacks. However, the original proposal using polarization encoding is sensitive to polarization rotations stemming from birefringence in fibers or misalignment. To overcome this problem, here we propose a robust QKD protocol without detector vulnerabilities based on decoherence-free subspaces using polarization-entangled photon pairs. A logical Bell state analyzer is designed specifically for such encoding. The protocol exploits common parametric down-conversion sources, for which we develop a MDI-decoy-state method, and requires neither complex measurements nor a shared reference frame. We have analyzed the practical security in detail and presented a numerical simulation under various parameter regimes, showing the feasibility of the logical Bell state analyzer along with the potential that double communication distance can be achieved without a shared reference frame.

Actions of genistein on contractile response of smooth muscle isolated from guinea pig gallbladder.

BACKGROUND: Defective contractile motility of the gallbladder is an important factor for gallstone formation. Estrogen might increase the risk of gallstones and cholecystitis, and estradiol inhibits the contractile activity of isolated strips of guinea pig gallbladder. The potential risks associated with hormone replacement therapy (HRT) include symptomatic gallstones. Phytoestrogen have been used to treat menopause syndromes by replacing traditional estrogen. This experiment aimed to determine the effects of the phytoestrogen genistein on the contractile response of smooth muscle strips isolated from guinea pig gallbladder and its possible mechanism of action. METHODS: Guinea pigs were sacrificed to remove the whole gallbladder. Two or three smooth muscle strips were cut longitudinally. Each strip was suspended in a tissue chamber containing Krebs solution. After 2 hours of equilibration, contractile response indexes were recorded. Different concentrations of genistein were added to the chamber and the contractile responses were measured. Each antagonist was added 2 minutes before genistein to study possible mechanisms. The effect of genistein on calcium-dependent contraction curves and biphasic contraction in calcium-free Krebs solution were measured. RESULTS: Genistein decreased the resting tension dose-dependently, and reduced the mean contractile amplitude and frequency in gallbladder strips. Ranitidine partly inhibited the effect of genistein, but methylene blue, Nomega-nitro-L-arginine, and propranolol hydrochloride did not influence this action. Genistein had no significant effects on calcium-dependent contraction. Genistein reduced the first contraction induced by acetylcholine chloride, but did not affect the second contraction caused by CaCl2. CONCLUSIONS: Genistein relaxed smooth muscle isolated from the gallbladder of guinea pigs and this might contribute to the formation of gallstones. The inhibitory action might be related to H2 receptors and the release of intracellular Ca2+ from sarcoplasmic reticulum. Replacing traditional estrogen with phytoestrogen to treat menopause syndromes may increase the risk of gallstone formation.