Optineurin is required for CYLD-dependent inhibition of TNFα-induced NF-κB activation

The nuclear factor kappa B (NF-κB) regulates genes that function in diverse cellular processes like inflammation, immunity and cell survival. The activation of NF-κB is tightly controlled and the deubiquitinase CYLD has emerged as a key negative regulator of NF-κB signalling. Optineurin, mutated in certain glaucomas and amyotrophic lateral sclerosis, is also a negative regulator of NF-κB activation. It competes with NEMO (NF-κB essential modulator) for binding to ubiquitinated RIP (receptor interacting protein) to prevent NF-κB activation. Recently we identified CYLD as optineurin-interacting protein. Here we have analysed the functional significance of interaction of optineurin with CYLD. Our results show that a glaucoma-associated mutant of optineurin, H486R, is altered in its interaction with CYLD. Unlike wild-type optineurin, the H486R mutant did not inhibit tumour necrosis factor α (TNFα)-induced NF-κB activation. CYLD mediated inhibition of TNFα-induced NF-κB activation was abrogated by expression of the H486R mutant. Upon knockdown of optineurin, CYLD was unable to inhibit TNFα-induced NF-κB activation and showed drastically reduced interaction with ubiquitinated RIP. The level of ubiquitinated RIP was increased in optineurin knockdown cells. Deubiquitination of RIP by over-expressed CYLD was abrogated in optineurin knockdown cells. These results suggest that optineurin regulates NF-κB activation by mediating interaction of CYLD with ubiquitinated RIP thus facilitating deubiquitination of RIP.     

Luminescence properties of Ce-doped ZrO2 phosphors synthesized by combustion method

Zr_1−xCe_xO₂ with x = 0.005, 0.01, 0.02, and 0.03 samples were synthesized using a combustion technique. The X-ray diffraction results revealed that Ce-doped ZrO₂ nanoparticles were in a monoclinic structure up to 1 mol% Ce concentration. The increase in the Ce concentration caused more distortion in the monoclinic structure of zirconia. The samples showed a mixed phase (monoclinic + tetragonal) beyond 1 mol% Ce content. The crystallite size (D) and strain (ε) were calculated from the Williamson–Hall equation. The D decreased from 25 ± 1 to 20 ± 1 nm and ε increased from 0.03 to 0.28% with an increase in Ce concentration. Photoluminescence (PL) spectra of Zr_1−xCe_xO₂ showed emission in the blue region under an excitation wavelength of 290 nm. Zr_0.995Ce_0.005O₂ showed the highest PL intensity with an average lifetime of 0.93 μs, and the PL intensity decreased with the increase in the Ce concentration. Thermoluminescence (TL) glow curves of Zr_1−xCe_xO₂ were measured after gamma irradiation (500 Gy) with a heating rate of 5 K s⁻¹. The TL curve of Zr_0.995Ce_0.005O₂ showed two prominent peaks at 412 K (peak 1) and 600 K (peak 2). The first TL glow peak was shifted towards a higher temperature at 440 K above 1 mol% Ce concentration. Repetitive TL measurements on the same aliquot exhibited excellent repeatability. Kinetic parameters associated with the TL peaks were calculated using the curve fitting method. Peak 1 followed non-first-order kinetics. The value of the activation energy of the 440 K peak was found to be 0.95 ± 0.01 eV for Zr_0.99Ce_0.01O₂. These findings showed that Zr_1−xCe_xO₂ might be used in lighting and radiation dosimeter applications.     

Inhibition of Soybean and Potato Lipoxygenases by Bhilawanols from Bhilawan (Semecarpus anacardium) Nut Shell Liquid and Some Synthetic Salicylic Acid Analogues

Bhilawanol diene (3) isolated from bhilawan nut shell liquid was found to be a potent inhibitor of both soybean and potato lipoxygenases with IC 50 values of 0.85 μM and 1.1 μM, respectively. However, the monoene (2) and saturated (1) bhilawanols exhibited relatively lower inhibitory activity. In addition, inhibition studies with synthetic analogues of salicylic acid (4 - 8) suggested that the unsaturated lipophilic side chain may be an absolute requirement for inhibitory activity.     

Extraction of Y2O3:Cr3+ nanophosphor by eco‐friendly approach and its suitability for white light‐emitting diode applications

Cr³⁺‐doped Y₂O₃ (0.5–9 mol%) was synthesized by a simple solution combustion method using Aloe vera gel as a fuel/surfactant. The final obtained product was calcined at 750°C for 3 h, which is the lowest temperature reported so far for the synthesis of this compound. The calcined product was confirmed for its crystallinity and purity by powder X‐ray diffraction (PXRD) studies which showed a single‐phase nano cubic phosphor. The particles size estimated by Scherrer formula was in the range of 6–19 nm. The UV–vis spectra showed absorption bands at 198, 272 and 372 nm having band gap energy in the range 4.00–4.26 eV. In order to investigate the possibility of its use in white light emitting display applications, the photoluminescence properties of Cr³⁺‐doped Y₂O₃ nanophosphors were studied at an excitation wavelength in the near ultraviolet (UV) light region (361 nm). The emission spectra consisted of emission peaks in the blue (⁴F_9/2 → ⁶H_15/2), orange (⁴F_9/2 → ⁶H_13/2) and red (⁴F_9/2 → ⁶H_11/2) regions. The CIE coordinates (0.33, 0.33) lie in the white light region. Hence Y₂O₃:Cr³⁺ can be used for white light‐emitting diode (LED) applications.     

Low temperature-synthesized MgAl2O4:Eu3+ nanophosphors and their structural validations using density functional theory: photoluminescence,photocatalytic, and electrochemical properties for multifunctional applications

A low temperature-assisted and oxalyl dihydrazide fuel-induced combustion synthesized series of uncalcined MgAl₂O₄:Eu³⁺ nanophosphors showed an average crystallite size of ~20 nm, and bandgap energy (E_g) of 4.50–5.15 eV, and were validated using density functional theory and found to match closely with the experimental values. The photoluminescence characteristic emission peaks of Eu³⁺ ions were recorded between 480 and 680 nm. The nanophosphors excited at 392 nm showed f–f transitions assigned as ⁵D₀→⁷F_J (J = 0, 1, 2, and 3). The optimized MgAl₂O₄ phosphors had Commission Internationale de l'Eclairage coordinates in the red region, a correlated colour temperature of 2060 K, and a colour purity of 98.83%. The estimated luminescence quantum efficiency ( $\eta$) was observed to be ~63% using Judd–Ofelt analysis. Electrochemical and photocatalytic performance were explored and indicated its multifunctional applications. Therefore, MgAl₂O₄:Eu³⁺ nanophosphors could be used for the fabrication of light-emitting diodes, industrial dye degradation, and as electrodes for supercapacitor applications.