The Mediator complex stimulates the cooperative assembly of a pre-initiation complex (PIC) and recruitment of RNA Polymerase II (Pol II) for gene activation. The core Mediator complex is organized into head, middle, and tail modules, and in budding yeast (Saccharomyces cerevisiae), Mediator recruitment has generally been ascribed to sequence-specific activators engaging the tail module triad of Med2-Med3-Med15 at upstream activating sequences (UASs). We show that yeast lacking Med2-Med3-Med15 are viable and that Mediator and PolII are recruited to promoters genome-wide in these cells, albeit at reduced levels. To test whether Mediator might alternatively be recruited via interactions with the PIC, we examined Mediator association genome-wide after depleting PIC components. We found that depletion of Taf1, Rpb3, and TBP profoundly affected Mediator association at active gene promoters, with TBP being critical for transit of Mediator from UAS to promoter, while Pol II and Taf1 stabilize Mediator association at proximal promoters.

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Hydrothermal-assisted CuS hierarchical architectures were grown in the presence of anionic sulfur sources, and the investigation of their degradation efficiency for a pesticide 4-chlorophenol (4-CP) under visible light irradiation was carried out. The dissociation of S 2– from the sulfur compound governs the nucleation of CuS followed by a specific pattern of growth to produce different morphologies. The self-assembled covellite spherical CuS flower architecture assembles in the presence of thiourea and exhibits the highest photodegradation activity. The open architecture of ∼2.3 μm spherical CuS flowers consisting of a ∼100 nm thick sheet encompasses a comparatively high surface area and particle growth along the (110) plane that facilitates more active sites for catalytic activity enhancement. The catalyst loading for 4-CP degradation has been optimized, and a detailed trapping mechanism has been explored.

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Monoclinic nanocuboid WO3 enhanced the photocatalyst efficiency of quasi nanobelt zinc oxide for dye degradation in the presence of visible light radiation.

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Porous and fluffy ZnO photocatalysts were successfully prepared via simple solution based combustion synthesis method. The photocatalytic inactivation of Escherichia coli bacteria was studied separately for both Ag substituted and impregnated ZnO under irradiation of natural solar light. A better understanding of substitution and impregnation of Ag was obtained by Raman spectrum and X-ray photoelectron analysis. The reaction parameters such as catalyst dose, initial bacterial concentration and effect of hydroxyl radicals via H 2 O 2 addition were also studied for ZnO catalyst. Effective inactivation was observed with 0.25 g/L catalyst loading having 10 9 CFU/mL bacterial concentration.With an increase in molarity of H 2 O 2 , photocatalytic inactivation was enhanced. The effects of different catalysts were studied, and highest bacterial killing was observed by Ag impregnated ZnO with 1 atom% Ag compared to Ag substituted ZnO. This enhanced activity can be attributed to effective charge separation that is supported by photoluminescence studies. The kinetics of reaction in the presence of different scavengers showed that reaction is significantly influenced by the presence of hole and hydroxyl radical scavenger with high efficiency.Successful synthesis of hexagonal wurtzite ZnO was carried having BET surface area of 16.8 m 2 /g. A modification to ZnO was performed by Ag substitution and impregnation bearing surface area of 14.2 m 2 /g and 12.4 m 2 /g, respectively. Substitution and impregnation of silver as Ag + ion and metallic Ag was confirmed from XPS. The photocatalytic tests showed that Ag impregnated ZnO exhibits excellent bacterial inactivation. The porous and open structure of ZnO favored the effective inactivation by increasing the number of active sites and effective charge separation observed in presence of Ag. Ag acts as an electron sink and hole as hydroxyl radical former for the photochemical killing of bacteria. The experiments for different radical and electron-hole trapping showed that the photogenerated holes and ·OH radicals are the main oxidative species for E. coli inactivation.