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A20 has been suggested to limit NF-jB activation by removing regulatory ubiquitin chains from ubiquitinated substrates. A20 is a ubiquitin-editing enzyme that removes K63-linked ubiquitin chains from adaptor proteins, such as RIP1, and then conjugates them to K48-linked polyubiquitin chains to trigger proteasomal degradation. To determine the role of the deubiquitinase function of A20 in downregulating NF-jB signaling, we have generated a knock-in mouse that lacks the deubiquitinase function of A20 (A20-OTU mice). These mice are normal and have no signs of inflammation, have normal proportions of B, T, dendritic, and myeloid cells, respond normally to LPS and TNF, and undergo normal NF-jB activation. Our results thus indicate that the deubiquitinase activity of A20 is dispensable for normal NF-jB signaling.

The synthesis of pure metal and metal-oxide nanoparticles of a desired size remains a significant challenge.We describe a novel, simple and convenient method for the synthesis of copper and copper(II) oxide nanoparticles with tailored sizes at room temperature from a common copper(II) salt (CuSO 4 ?5H 2 O) in TX-100/n-hexanol/cyclohexane/water by a reverse microemulsion route. It was found that reduction with hydrazine hydrate (reduction potential 1.15 V) in an inert N 2 environment gives copper nanoparticles whereas reaction with sodium borohydrate (reduction potential 1.24 V) in aerobic condition gives copper(II) oxide nanoparticles. Several parameters were modulated to examine their effects on the structural properties of nanoparticles, namely the size and morphology of the nanoparticles. The size of the copper and copper(II) oxide nanoparticles can be easily controlled by changing the molar ratio of water to surfactant or by altering the concentration of the reactants. The nanoparticles were characterized using a variety of analytical techniques like X-ray diffraction (XRD), quasi elastic light scattering (QELS), UV-visible absorption spectroscopy, transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDAX). Our studies reveal that the nanoparticles are spherical in shape and have an average size distribution of 5-100 nm. Our protocol provides a rapid and low cost procedure for the synthesis of both copper and copper(II) oxide nanoparticles in the same microemulsion pool. The nanoparticles so formed have been successfully used for catalyzing various chemical reactions.

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The toxicity of nanomaterials can sometimes be attributed to photogenerated reactive oxygen species (ROS), but these ROS can also be scavenged by nanomaterials, yielding opportunities for crossover between the properties. The morphology of nanomaterials also influences such features due to defect-induced properties. Here we report morphology-induced crossover between pro-oxidant activity (ROS generation) and antioxidant activity (ROS scavenging) of MgO. To study this process in detail, we prepared three different nanostructures of MgO (nanoparticles, nanoplates, and nanorods) and characterized them by HRTEM. These three nanostructures effectively generate superoxide anions (O2 •–) and hydroxyl radicals (•OH) at higher concentrations (>500 μg/mL) but scavenge O2 •– at lower concentrations (40 μg/mL) with successful crossover at 200 μg/mL. Nanorods of MgO generate the highest levels of O2 •–, whereas nanoparticles scavenge O2 •– to the highest extent (60%). Photoluminescence studies reveal that such crossover is based on the suppression of F2+ and the evolution of F+, F2 +, and F2 3+ defect centers. The evolution of these defect centers reflects the antibacterial activity of MgO nanostructures which is initiated at 200 μg/mL against Gram-positive S. aureus ATCC 29737 and among different bacterial strains including Gram-positive B. subtilis ATCC 6633 and M. luteus ATCC 10240 and Gram-negative E. coli ATCC K88 and K. pneumoniae ATCC 10031. Nanoparticles exhibited the highest antibacterial (92%) and antibiofilm activity (17%) against B. subtilis ATCC 6633 in the dark. Interestingly, the nitrogen-centered free radical DPPH is scavenged (100%) by nanoplates due to its large surface area (342.2 m2/g) and the presence of the F2 + defect state. The concentration-dependent interaction with an antioxidant defense system (ascorbic acid (AA)) highlights nanoparticles as potent scavengers of O2 •– in the dark. Thus, our findings establish guidelines for the selection of MgO nanostructures for diverse therapeutic applications.

Cu-nanoparticulates in Guar-gum at room temperature were investigated for the first time as a recyclable catalytic system in organic synthesis. The catalytic potential of these materials were evaluated in the Huisgen [3 + 2]-cycloaddition of azides and alkynes without additives under ambient conditions which offers several advantages, viz. high yields, clean reactions, short reaction times, recyclability of the catalyst and a simple workup procedure. † Electronic supplementary information (ESI) available: Procedural details for the synthesis and characterization of copper nanoparticulates in Guar-gum associated with this article can be found, in the online version. See

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