Structure of human Cdc45 and implications for CMG helicase function.

Cell division cycle protein 45 (Cdc45) is required for DNA synthesis during genome duplication, as a component of the Cdc45-MCM-GINS (CMG) helicase. Despite its essential biological function, its biochemical role in DNA replication has remained elusive. Here we report the 2.1-Å crystal structure of human Cdc45, which confirms its evolutionary link with the bacterial RecJ nuclease and reveals several unexpected features that underpin its function in eukaryotic DNA replication. These include a long-range interaction between N- and C-terminal DHH domains, blocking access to the DNA-binding groove of its RecJ-like fold, and a helical insertion in its N-terminal DHH domain, which appears poised for replisome interactions. In combination with available electron microscopy data, we validate by mutational analysis the mechanism of Cdc45 association with the MCM ring and GINS co-activator, critical for CMG assembly. These findings provide an indispensable molecular basis to rationalize the essential role of Cdc45 in genomic duplication.We would like to thank Ben Luisi for help with X-ray data collection, Alessandro Costa for sharing the cryoEM data of the CMG complex before publication and Joseph Maman for help with the analysis of Cdc45-DNA interactions. This work was supported by a Wellcome Trust Senior Investigator award to LP (104641/Z/14/Z) and a Cambridge Gates PhD scholarship to ACS. VC is funded by the Associazione Italiana per Ricerca sul Cancro (AIRC), the European Research Council (ERC) consolidator grant (614541), the Association for International Cancer Research (AICR), the Giovanni-Armenise award to VC, the Epigen Progetto Bandiera and the Fondazione Telethon.This is the final version of the article. It first appeared from Nature via https://doi.org/10.1038/ncomms1163

Improved Performances of a Fluidized Bed Photoreactor by a Microscale Illumination System

The performances of a gas-solid two-dimensional fluidized bed reactor in photocatalytic selective oxidation reactions, irradiated with traditional UV lamps or with a microscale illumination system based on UV emitting diodes (UVA-LEDs), have been compared. In the photocatalytic oxidative dehydrogenation of cyclohexane to benzene on catalyst the use of UVA-LEDs modules allowed to achieve a cyclohexane conversion and benzene yield higher than those obtained with traditional UV lamps. The better performances with UVA-LEDs are due to the UVA-LEDs small dimensions and small-angle emittance, which allow photons beam be directed towards the photoreactor windows, reducing the dispersion outside of photoreactor or the optical path length. As a consequence, the effectively illuminated mass of catalyst is greater. We have found that this illumination system is efficient for photo-oxidative dehydrogenation of cyclohexane to cyclohexene on sulphated and ethanol to acetaldehyde on

Investigation of the Deactivation Phenomena Occurring in the Cyclohexane Photocatalytic Oxidative Dehydrogenation on MoOx/TiO2 through Gas Phase and in situ DRIFTS Analyses

In this work, the results of gas phase cyclohexane photocatalytic oxidative dehydrogenation on MoOx/SO4/TiO2 catalysts with DRIFTS analysis are presented. Analysis of products in the gas-phase discharge of a fixed bed photoreactor was coupled with in situ monitoring of the photocatalyst surface during irradiation with an IR probe. An interaction between cyclohexane and surface sulfates was found by DRIFTS analysis in the absence of UV irradiation, showing evidence of the formation of an organo-sulfur compound. In particular, in the absence of irradiation, sulfate species initiate a redox reaction through hydrogen abstraction of cyclohexane and formation of sulfate (IV) species. In previous studies, it was concluded that reduction of the sulfate (IV) species via hydrogen abstraction during UV irradiation may produce gas phase SO2 and thereby loss of surface sulfur species. Gas phase analysis showed that the presence of MoOx species, at same sulfate loading, changes the selectivity of the photoreaction, promoting the formation of benzene. The amount of surface sulfate influenced benzene yield, which decreases when the sulfate coverage is lower. During irradiation, a strong deactivation was observed due to the poisoning of the surface by carbon deposits strongly adsorbed on catalyst surface

Mechanical Harvesting Line Setting of Giant Reeds

This study evaluated the possibility of adopting haymaking farming machinery in giant reed (Arundo donax L.) harvesting. The test shows the technical and energy aspects of mechanical harvesting using only one specific machine, a shredding machine, designed and developed by an Italian constructor for large biomass herbaceous crops (giant reed, sorghums, switchgrass, Mischantus, etc). It is designed for high vegetative growth crops, as it is able to spread products over all soil surfaces or, alternatively, carry out windrowing. Tests were conducted in the south of Italy (Campania region) on the experimental farm Torre Lama in Bellizzi (SA). Biomass was shredded, dried in the field, and baled for use in a logistic chain and storage. The first step was the cutting and shredding of biomass crops with the specific shredder rear-mounted in an agricultural tractor. The biomass then was dried on the field, constantly monitored for moisture content, and finally, baled with a trailed round baler for storage (second step) and used in a specific logistic chain. The test showed good performance of the shredder machine between 1.17 and 1.77 ha h−1 with an operative speed between 3.9 and 5. 9 km h−1. To define the hourly production, a high wet production level of 60.70 t ha−1 and a low level of 56 t ha−1 were used as references. Under the climatic conditions of the experimental test, this harvesting system showed some advantages, such as the possibility of immediate and long-term biomass storage (less than 14% moisture content), the potential alternative use of the biomass, and the reduced resource use compared to that of other ordinary crops growing in the area

Enhanced visible-light-driven photodegradation of Acid Orange 7 azo dye in aqueous solution using Fe-N co-doped TiO2

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Improved Performances of a Fluidized Bed Photoreactor by a Microscale Illumination System

The performances of a gas-solid two-dimensional fluidized bed reactor in photocatalytic selective oxidation reactions, irradiated with traditional UV lamps or with a microscale illumination system based on UV emitting diodes (UVA-LEDs), have been compared. In the photocatalytic oxidative dehydrogenation of cyclohexane to benzene on MoOx/TiO2-A12O3 catalyst the use of UVA-LEDs modules allowed to achieve a cyclohexane conversion and benzene yield higher than those obtained with traditional UV lamps. The better performances with UVA-LEDs are due to the UVA-LEDs small dimensions and small-angle emittance, which allow photons beam be directed towards the photoreactor windows, reducing the dispersion outside of photoreactor or the optical path length. As a consequence, the effectively illuminated mass of catalyst is greater. We have found that this illumination system is efficient for photo-oxidative dehydrogenation of cyclohexane to cyclohexene on sulphated MoOx/-A12O3 and ethanol to acetaldehyde on VOx/TiO2