Mcgeelowe6303

Enterohemorrhagic Escherichia coli (EHEC) outbreaks are commonly associated with contaminated food sources. Unlike normal intestinal bacteria, EHEC are lysogens of lambdoid bacteriophages that also carry a gene for Shiga toxin. Oxidative attack by the immune system or other stressors on the bacterial host can activate the lytic pathway of the latent phage genome to produce phage progeny and the release of Shiga toxin into the surrounding tissues. Within the genomes of bacteriophage λ and Shiga toxin-expressing (Stx+) phages such as φ24B and φP27, there is a conserved set of open reading frames that is located between the exo and xis genes that influences the lysogenic-lytic decision. In this report, we have focused on the largest exo-xis region open reading frame termed ea22 that has been shown previously to have prolysogenic properties. Using a variety of biophysical and bioinformatic methods, we demonstrate that λ and φP27 Ea22 proteins are tetrameric in solution and can be considered in terms of an amino-terminal region, a central coiled-coil region, and a carboxy-terminal region. The carboxy-terminal regions of λ and φ24B Ea22, expressed on their own, form dimers with exceptional thermostability. Limited proteolysis of φP27 Ea22 also identified a C-terminal region along the predicted boundaries. While the three Ea22 proteins all appear to have the hallmarks of a domain in their respective C-terminal regions, each sequence is remarkably dissimilar. To reconcile this difference among Ea22 proteins from λ and Stx+ phages alike, we speculate that each Ea22 may achieve the same function by targeting different components of the same regulatory process in the host.In the present study, a novel catalytic route for the Knoevenagel condensation reaction has been developed by Pickering interfacial catalysis using magnesium oxide (MgO) as both an emulsion stabilizer and a base catalyst. MgO was prepared by the precipitation method using sodium hydroxide or ammonium hydroxide as the precipitating agent and calcined at different temperatures. The calcined samples were characterized by XRD, SEM, TEM, AFM, BET, and DLS techniques. The catalytic application of the emulsions stabilized by MgO was investigated for the Knoevenagel condensation reaction of benzaldehyde and its derivatives with malononitrile. Selleckchem BGB-8035 All of the reactions were carried out at an ambient temperature (30 °C) under static conditions without stirring. Both the emulsion-stabilizing ability and the catalytic activity of MgO were found to be affected by the method of preparation, calcination temperature, and the nature of the oil phase. It was observed that the method of preparation varied the texture and morphology of MgO and thus the stability and droplet size of the emulsion formed. This was further reflected in the catalytic activity. The highest yield (87%) of the condensation product was obtained with MgO prepared by precipitation using a strong base (NaOH) and further calcined at 400 °C. The developed catalytic system offers several green chemistry advantages such as reusable solid-base catalyst and use of a single material as both emulsion stabilizer and catalyst. Room-temperature reaction under static conditions is an additional advantage of the developed catalytic system.This study aims to investigate how the morphology of cellulose influences the hydrolysis and carbonization during hydrothermal treatment at temperatures between 180 and 240 °C. The morphology of cellulose, especially different crystallinities and degrees of polymerization, is represented by microcrystalline cellulose and α-cellulose. Kinetic analysis is considered a tool to allow the determination of the mechanisms of the two types of cellulose during the hydrothermal process. A kinetic model, in which cellulose is assumed to be hydrolyzed to a limited extent, is proposed. Five scenarios are used as models for pyrolysis of nonhydrolyzed cellulose that forms primary char, along with reaction pathways of hydrolyzable cellulose and its derivatives that latterly form secondary char. The morphologies of solid products are in good agreement with the results of the proposed model.In this study, a novel porous hybrid material, poly(lauryl methacrylate) polymer-grafted UiO-66-NH2 (UiO = University of Oslo), was synthesized for efficient extraction of polycyclic aromatic hydrocarbons (PAHs) from aqueous samples. The polymer end-tethered covalently to the MOF's surface was synthesized by surface-initiated atom transfer radical polymerization, revealing a distinct type of morphology. The adsorbent was characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, powder X-ray diffraction, N2 adsorption-desorption analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The analyses were carried out by gas chromatography-mass spectrometry. Parameters including the type and volume of the eluent, the amount of the adsorbent, and adsorption and desorption times were investigated and optimized. Under optimal conditions, the limit of detection, intraday precision, and interday precision were in the range of 3-8 ng L-1, 1.4-3.1, and 4.1-6.5%, respectively. The procedure was used for analysis of PAHs from natural water samples.In this work, a combination of mechanical and chemical pretreatments using urea on corn residues (leaves and stems) was evaluated to obtain total reducing sugars (TRSs). The residues were characterized via high-performance liquid chromatography (HPLC) to quantify biomass composition. During the mechanical pretreatment, the particle size of the biomass was reduced to 0.5, 1, and 2 mm. The chemical pretreatment was performed with urea solution at different concentrations (2, 5, and 10% w/v) and a fixed biomass-to-solvent ratio of 125 (g/mL) as well as stirring at 150 rpm for 20 h. The effect of temperature on the pretreatment results was evaluated by varying such operating variables in 30 and 50 °C. After both pretreatments, hydrolysis was carried out in an autoclave using sulfuric acid at 1% v/v at 121 °C for 1 h. The content of TRS was quantified using 3,5-dinitrosalicylic acid (DNS) method and biomass after pretreatment was characterized via Fourier transform infrared (FT-IR). For both leaves and stems, the HPLC technique reported the presence of 47.