Porcine reproductive and respiratory syndrome virus infection induces microRNA novel-216 production to facilitate viral-replication by targeting MAVS 3´UTR.

Porcine reproductive and respiratory syndrome virus (PRRSV) has caused significant economic losses in the swine industry. In this study, the high-throughput sequencing, microRNAs (miRNAs) mimic, and lentivirus were used to screen for potential miRNAs that can promote PRRSV infection in porcine alveolar macrophages or Marc-145 cells. It was observed that novel-216, a previously unidentified miRNA, was upregulated through the p38 signaling pathway during PRRSV infection, and its overexpression significantly increased PRRSV replication. Further analysis revealed that novel-216 regulated PRRSV replication by directly targeting mitochondrial antiviral signaling protein (MAVS), an upstream molecule of type Ⅰ IFN that mediates the production and response of type Ⅰ IFN. The proviral function of novel-216 on PRRSV replication was abolished by MAVS overexpression, and this effect was reversed by the 3'UTR of MAVS, which served as the target site of novel-216. In conclusion, this study demonstrated that PRRSV-induced upregulation of novel-216 served to inhibit the production and response of typeⅠ IFN and facilitate viral replication, providing new insights into viral immune evasion and persistent infection.

Duck Complement Factor H Binds to Outer Membrane Protein Omp24 of Riemerella anatipestifer.

The resistance to serum complement-mediated killing is a vital virulence property of microbial pathogens. Complement factor H (FH) is a key negative regulator of the complement alternative pathway (AP) that prevents formation and accelerates the decay of AP C3 convertase and acts as a cofactor in the inactivation of C3b. Pathogens can recruit host FH through their surface proteins to escape the clearance of the complement system. Riemerella anatipestifer could also evade the complement system attack to achieve host infection, but the mechanism is still unclear. In this study, the R. anatipestifer proteins that could interact with FH in host serum were screened and analyzed, and the functions were determined. Affinity chromatography with a Ni-nitrilotriacetic acid Sefinose column and mass spectrometry identified three outer membrane proteins (Omp) of R. anatipestifer, Omp54, Omp53, and Omp24, as potential FH-binding proteins. We then successfully conducted the prokaryotic expression and polyclonal antibody preparation of three candidate proteins. Indirect immunofluorescence assay showed that three candidate proteins were all present in R. anatipestifer. The affinity blotting assay, anti-serum-inhibiting assay, and serum bactericidal assay presented evidence that Omp24 could bind FH. Moreover, FH bound to Omp24 was associated with resistance to the alternative pathway and functional for R. anatipestifer survival in the normal duck serum. These results suggested that R. anatipestifer Omp24 was a FH-binding protein and the interaction with FH blocked the alternative pathway. Recruitment of complement regulatory proteins may facilitate better R. anatipestifer resistance to this vital line of host defense.

Artículo regular­El factor H del complemento de pato se une a la proteína de la membrana externa Omp24 de Riemerella anatipestifer La resistencia a la destrucción mediada por el complemento sérico es una propiedad vital para la virulencia de los patógenos microbianos. El factor de complemento H (FH) es un regulador negativo clave de la vía alterna del complemento (AP) que previene la formación y acelera la descomposición de la C3 convertasa de la vía alterna y actúa como cofactor en la inactivación de C3b. Los patógenos pueden reclutar factor H del huésped a través de sus proteínas de superficie para escapar de la destrucción por el sistema del complemento. Riemerella anatipestifer también pudo evadir el ataque del sistema del complemento para lograr la infección del huésped, pero el mecanismo aún no está claro. En este estudio, se seleccionaron y analizaron las proteínas de R. anatipestifer que podrían interactuar con el factor H en el suero del huésped y se determinaron las funciones. La cromatografía de afinidad con una columna de sefinosa de Ni-NTA y la espectrometría de masas identificaron tres proteínas de la membrana externa de R. anatipestifer, Omp54, Omp53 y Omp24, como posibles proteínas que se unen al factor H. Posteriormente, se llevó a cabo con éxito la expresión procariota y la preparación de anticuerpos policlonales de las tres proteínas candidatas. El ensayo de inmunofluorescencia indirecta mostró que las tres proteínas candidatas estaban presentes en R. anatipestifer. El ensayo de transferencia para afinidad, el ensayo anti-inhibidor del suero y el ensayo bactericida sérico presentaron evidencia de que la proteína Omp24 podría unirse al factor H. Además, el factor H unido a la proteína Omp24 se asoció con resistencia a la vía alterna y funcional para la supervivencia de R. anatipestifer en el suero de pato normal. Estos resultados sugirieron que la proteína Omp24 de R. anatipestifer era una proteína de unión al factor H y que la interacción con este factor bloqueaba la vía alterna del complemento. El reclutamiento de proteínas reguladoras del complemento puede facilitar una mejor resistencia de R. anatipestifer a esta línea vital de defensa del huésped.

Cryptotanshinone Attenuates Ischemia/Reperfusion-induced Apoptosis in Myocardium by Upregulating MAPK3.

ABSTRACT: Chinese people have used the root of Salvia miltiorrhiza Bunge (called "Danshen" in Chinese) for centuries as an anticancer agent, anti-inflammatory agent, antioxidant, and cardiovascular disease drug. In addition, Danshen is considered to be a drug that can improve ischemia/reperfusion (I/R)-induced myocardium injury in traditional Chinese medicine. However, Danshen is a mixture that includes various bioactive substances. In this study, we aimed to identify the protective component and mechanism of Danshen on myocardium through network pharmacology and molecular simulation methods. First, cryptotanshinone (CTS) was identified as a potential active compound from Danshen that was associated with apoptosis by a network pharmacology approach. Subsequently, biological experiments validated that CTS inhibited ischemia/reperfusion-induced cardiomyocyte apoptosis in vivo and in vitro. Molecular docking techniques were used to screen key target information. Based on the simulative results, MAPKs were verified as well-connected molecules of CTS. Western blotting assays also demonstrated that CTS could enhance MAPK expression. Furthermore, we demonstrated that inhibition of the MAPK pathway reversed the CTS-mediated effect on cardiomyocyte apoptosis. Altogether, our work screened out CTS from Danshen and demonstrated that it protected cardiomyocytes from apoptosis.

Strong coupling of single quantum dots with low-refractive-index/high-refractive-index materials at room temperature.

Strong coupling between a cavity and transition dipole moments in emitters leads to vacuum Rabi splitting. Researchers have not reported strong coupling between a single emitter and a dielectric cavity at room temperature until now. In this study, we investigated the photoluminescence (PL) spectra of colloidal quantum dots on the surface of a SiO2/Si material at various collection angles at room temperature. We measured the corresponding reflection spectra for the SiO2/Si material and compared them with the PL spectra. We observed PL spectral splitting and regarded it as strong coupling between colloidal quantum dots and the SiO2/Si material. Upper polaritons and lower polaritons exhibited anticrossing behavior. We observed Rabi splitting from single-photon emission in the dielectric cavity at room temperature. Through analysis, we attributed the Rabi splitting to strong coupling between quantum dots and bound states in the continuum in the low-refractive-index/high-refractive-index hybrid material.

Two-photon interferences on a silica-on-silicon chip with telecom-band photon pairs generated in a fiber.

We report two-photon interferences on a silica-on-silicon chip of Mach-Zehnder interferometer using telecommunication-band correlated photon pairs. The photon pairs were generated by spontaneous four-waving mixing process in a dispersion-shifted fiber. The integrated chip, which was fabricated by standard silica-on-silicon planar lightwave circuit technology, contained a Mach-Zehnder interferometer with a thermo-optic phase shifter. The insertion loss of the interferometer was less than 1 dB. We demonstrated two-photon interferences with both degenerate- and non-degenerate-frequency photon pairs on the Mach-Zehnder interferometer chip. A high fringe visibility was achieved in the interference with nondegenerate-frequency photons. Properties of quantum interference were demonstrated in the interference with degenerate-frequency photon pairs, which is an important way to manipulate the quantum state. These results show great potential of silica-on-silicon photonic chips in applications for the fiber-chip scheme in quantum networks.

Resonant energy transfer between patterned InGaN/GaN quantum wells and CdSe/ZnS quantum dots.

We explore an easy method for preparation of a hybrid device of a photonic crystal InGaN/GaN quantum well (QW) and colloidal quantum dots using conventional photolithography. It is demonstrated from electroluminescence spectra that Förster resonance energy transfer takes place efficiently between the photonic crystal InGaN/GaN QW and CdSe/ZnS colloidal quantum dots. From the photoluminescence decay of the InGaN/GaN QW, the largest Förster resonance energy transfer efficiency between the photonic crystal GaN quantum well and colloidal quantum dots is measured as 88% and the corresponding Förster-resonance-energy-transfer fraction reached 42%. An easy approach is explored to realize a highly efficient electrically driven colloidal quantum dot device using the Förster-resonance-energy-transfer mechanism.

Enhanced emission of charged-exciton polaritons from colloidal quantum dots on a SiN/SiO2 slab waveguide.

We investigate the photoluminescence (PL) spectra and the time-resolved PL decay process from colloidal quantum dots on SiN/SiO2 wet etched via BOE (HF:NH4F:H2O). The spectrum displays multi-peak shapes that vary with irradiation time. The evolution of the spectral peaks with irradiation time and collection angle demonstrates that the strong coupling of the charged-exciton emission to the leaky modes of the SiN/SiO2 slab waveguide predominantly produces short-wavelength spectral peaks, resulting in multi-peak spectra. We conclude that BOE etching enhances the charged-exciton emission efficiency and its contribution to the total emission compared with the unetched case. BOE etching smoothes the electron confinement potential, thus decreasing the Auger recombination rate. Therefore, the charged-exciton emission efficiency is high, and the charged-exciton-polariton emission can be further enhanced through strong coupling to the leaky mode of the slab waveguide.

Lower AMP-activated protein kinase level is associated with the vulnerability of coronary atherosclerotic plaques by attenuating the expression of monocyte autophagy.

BACKGROUND: Coronary atherosclerotic plaque formation is driven by macrophage infiltration. Monocytes and macrophages contribute to the progression of atherosclerosis. However, research on the relationship between AMP-activated protein kinase (AMPK) and vulnerable atherosclerotic plaques is still insufficient. In the present study, we aimed to elucidate the adaptive mechanism between autophagy of peripheral blood monocytes (PBMs) and the rupture of atherosclerotic plaques. We investigated whether AMPK and autophagy of monocytes can enhance the stability of coronary atherosclerotic plaques in the human body. PATIENTS AND METHODS: Samples of PBMs were collected and isolated from all patients with stable angina pectoris (SAP), non-ST-segment elevation acute coronary syndrome, ST-segment elevation acute myocardial infarction, and without coronary artery disease (control). Then, western blot was used to detect the expression levels of AMPK and autophagy-related protein. RESULTS: The expression levels of beclin-1 and ATG7 were all significantly lower in the acute coronary syndrome groups than those in the SAP and control groups (all P<0.01). The level of phosphorylated AMPK was significantly decreased in patients with acute coronary syndrome compared with those in the SAP and control groups (P<0.01). However, there was no statistical difference between the SAP group and the control group. The activation of mTOR was distinctly increased in the STEMI group (P<0.05). CONCLUSION: Therefore, our work is novel in showing that AMPK of PBMs may decrease plaque vulnerability and subsequent plaque rupture through activation of autophagy.

Bonding III-V material to SOI with transparent and conductive ZnO film at low temperature.

A procedure of bonding III-V material to SOI at low temperature using conductive and transparent adhesive ZnO as intermediate layer is demonstrated. Bonding layer thickness of less than 100 nm was achieved in our experiment that guaranteed good light coupling efficiency between III-V and silicon. This bonding method showed good bonding strength with shear stress of 80 N/cm(2). The lowest resistance of the bonded samples was 48.9 Ω and the transmittance of the spin-coated ZnO layer was above 99%. This procedure is applicable for fabricating hybrid III-V/Si lasers.

Controlling the influence of Auger recombination on emission from colloidal quantum dots by photonic crystal.

By investigating the time-resolved spectra of colloidal quantum dots (QDs) on silicon nitride (SiN) photonic crystals (PhCs), it is found that the ratio of charged-exciton (trion) emission and the multiexciton emission to the total emission can be controlled by two-dimensional PhCs. Even by conservative estimates, the ratios of trion to total emission from QDs on PCs reaches 10%, which is much larger than that of the dark state seen in the blinking phenomenon of single QDs. Therefore Auger recombination could be controlled by SiN PhCs.

Surface recombination and charged exciton in nanocrystal quantum dots on photonic crystals under two-photon excitation.

In this study, the two-photon excited fluorescence spectra from cadmium selenide quantum dots (QDs) on a silicon nitride photonic crystal (PhC) membrane under femtosecond laser irradiation were investigated. These spectra can be fit to a tri-Gaussian function in which one component is negative in amplitude, and in which the Gaussian components with positive amplitude are assigned to exciton emission and charged-exciton emission and that with negative amplitude is assigned to absorption from surface recombination. The photonic crystal enhance the charged-exciton emission and exciton emission and, at the same time, also the absorption from surface recombination. Both the charged-exciton emission and the surface recombination are related to Auger recombination; therefore, the photonic crystal controls both radiative recombination and non-radiative recombination. The asymmetries of the two-photon excited fluorescence spectra are due to not only the location of the resonant guide mode of the PhC slab but also the enhancement of the absorption from surface recombination by PhC.

Electro-optic modulator based on a photonic crystal slab with electro-optic polymer cladding.

A type of modulator based on a shallow-etched photonic crystal (PC) slab of silicon-on-insulator material with electro-optic (EO) polymer cladding is designed and investigated. The transmission spectra of the PC slab with the EO polymer are calculated using a finite-difference time-domain method. The band structure and the field distribution of the guided mode resonance are calculated and analyzed. The modulation voltage and bandwidth of the hybrid modulator are simulated. It is shown that flexible designs of low-voltage modulation (0.2 V) or high-bandwidth modulation (62 GHz) can be obtained with the hybrid modulator.

Enhanced trion emission from colloidal quantum dots with photonic crystals by two-photon excitation.

For colloidal quantum dots, the ongoing biggest problem is their fluorescence blinking. Until now, there is no generally accepted model for this fluorescence blinking. Here, two-photon excited fluorescence from CdSe/ZnS nanocrystals on silicon nitride photonic crystals is studied using a femtosecond laser. From analysis of the spectra and decay processes, most of the relative trion efficiency is larger than 10%, and the largest relative trion efficiency reaches 46.7%. The photonic crystals enhance the trion emission of CdSe/ZnS nanocrystals, where the enhancement is due to the coupling of the trion emission to the leaky mode of the photonic crystal slab. Moreover, the photonic crystals enhance the Auger-assisted trapping efficiency of electrons/holes to surface states, and then enhance the efficiency of the generations of charge separation and DC electric field, which modifies the trion spectrum. Therefore, a model is present for explaining the mechanism of fluorescence blinking including the effect of the environment.

[High transmission and low group velocity of a photonic crystal coupled-cavity waveguide].

A two-dimensional photonic crystal coupled-cavity waveguide was designed and optimized by combining photonic crystal wavguide and cavity, transmission spectra of the waveguide were calculated by using FDTD method, and the transmittance and the group velocity were obtained through the transmission spectra. The calculation results show that a group velocity of upsilon(g) = c/130 and corresponding transmission of 20.1% can be obtained at wavelength 1.551 microm, and a group velocity of upsilon(g) = c/50 and transmission of 29.2% was obtained at wavelength 1.502 microm. The slow light in the waveguide was also analyzed by using photonic bandstructure calculated by plane-wave-expansion (PWE) method. The results of the photonic crystal waveguide with high transmission and low group velocity will have potential application in optical storage, optical delay and photonic integration.

Fabrication of two-dimensional Ta2O5 photonic crystal slabs with ultra-low background emission toward highly sensitive fluorescence spectroscopy.

A two-dimensional tantalum pentoxide (Ta2O5) photonic crystal (PC) slab with low-background emission was fabricated and a 12-fold enhancement of fluorescence from the organic dyes of perylene diimide adsorbed on the surface of the PCs was observed. The background emissions of the Ta2O5 substrates with and without the PCs after thermal annealing at 600°C with oxygen gas were comparable to that of a well-cleaned cover glass. This is to date the lowest level of background emissions of two-dimensional PCs using materials with a high refractive index (>2). The results reported here provide new insights into the fabrication of the photonic devices that enable highly sensitive fluorescence microscopy or optical detections.

Modification of two-photon excited fluorescence from quantum dots on SiN photonic crystals.

We investigate two-photon excited fluorescence from CdSe quantum dots with a center-emitting wavelength of 655 nm on SiN photonic crystals. We find that two-photon excited fluorescence is enhanced by more than 1 order of magnitude in the vertical direction when a photonic crystal is used compared to the fluorescence spectra in the absence of photonic crystals. The spectrum of two-photon excited fluorescence from quantum dots on SiN photonic crystal is observed to shift to blue compared to that from quantum dots on SiN without photonic crystals.

Experimental demonstration on structure-parameter dependence of photonic crystal optical spectrum.

We present fabrication and experimental measurement of a series of photonic crystal waveguides and coupled structure of PC waveguide and PC micro-cavity. The complete devices consist of an injector taper down from 3 microm into a triangular-lattice air-holes single-line-defect waveguide. We fabricated these devices on a silicon-on-insulator substrate and characterized them using tunable laser source. We've obtained high-efficiency light propagation and broad flat spectrum response of photonic-crystal waveguides. A sharp attenuation at photonic crystal waveguide mode edge was observed for most structures. The edge of guided band is shifted about 31 nm with the 10 nm increase of lattice constant. Mode resonance was observed in coupled structure. Our experimental results indicate that the optical spectra of photonic crystal are very sensitive to structure parameters.

Dynamics of spontaneous emission from SiN with two-dimensional photonic crystals.

We investigated the dynamics of spontaneous emission from a photonic crystal etched into a SiN slab. After fitting the decay curves of the emission to double exponential functions, we divided the dynamic process of the spontaneous emission into a fast process and a slow process. It was observed that the presence of the photonic crystal increased the proportion of the fast decay component, and consequently, the emission rate and time-integrated emission intensity were also enhanced. These enhancements were a result of the coupling of the guide modes to the leaky modes of the photonic crystal slab waveguide.