NMR-Based Metabolic Profiles of Intact Zebrafish Embryos Exposed to Aflatoxin B1 Recapitulates Hepatotoxicity and Supports Possible Neurotoxicity

Aflatoxin B1 (AFB1) is a widespread contaminant of grains and other agricultural crops and is globally associated with both acute toxicity and carcinogenicity. In the present study, we utilized nuclear magnetic resonance (NMR), and specifically high-resolution magic angle spin (HRMAS) NMR, coupled to the zebrafish (Danio rerio) embryo toxicological model, to characterize metabolic profiles associated with exposure to AFB1. Exposure to AFB1 was associated with dose-dependent acute toxicity (i.e., lethality) and developmental deformities at micromolar (≤ 2 µM) concentrations. Toxicity of AFB1 was stage-dependent and specifically consistent, in this regard, with a role of the liver and phase I enzyme (i.e., cytochrome P450) bioactivation. Metabolic profiles of intact zebrafish embryos exposed to AFB1 were, furthermore, largely consistent with hepatotoxicity previously reported in mammalian systems including metabolites associated with cytotoxicity (i.e., loss of cellular membrane integrity), glutathione-based detoxification, and multiple pathways associated with the liver including amino acid, lipid, and carbohydrate (i.e., energy) metabolism. Taken together, these metabolic alterations enabled the proposal of an integrated model of the hepatotoxicity of AFB1 in the zebrafish embryo system. Interestingly, changes in amino acid neurotransmitters (i.e., Gly, Glu, and GABA), as a key modulator of neural development, supports a role in recently-reported neurobehavioral and neurodevelopmental effects of AFB1 in the zebrafish embryo model. The present study reinforces not only toxicological pathways of AFB1 (i.e., hepatotoxicity, neurotoxicity), but also multiple metabolites as potential biomarkers of exposure and toxicity. More generally, this underscores the capacity of NMR-based approaches, when coupled to animal models, as a powerful toxicometabolomics tool.

Unraveling the Core of The Gran Pirámide From Cholula, Puebla. A Compositional and Microstructural Analysis of the Adobe

ABSTRACTThe Gran Pirámide, a Mexican cultural heritage site, is located at the archaeological site of Cholula, Puebla, Mexico. At the base of its platform this pyramid is the largest in the world. It was built in layers from 800 to 1100 AD by the Cholultecan pre-Hispanic culture. The archaeological site is famous by its great mural paintings that have been well-studied. The pyramid was built with earthen construction, a system of multiple bulding episodes with layers of adobe. The building material, adobe, has not been well studied. Due to its fragile condition, a more extensive study was conducted to understand the behavior of the building and the mural paintings substrate, in order to propose conservation strategies.Geological context of the area was the starting point to propose the relevant materials used in its construction. That was a fundamental key for the interpretation of the experimental techniques used that include X-ray Diffraction (XRD), Particle-Induced X-ray Emission (PIXE), 29Si and 27Al Nuclear-Magnetic Resonance with Magic-Angle Spin (NMR-MAS), Thermal Analysis, Optical and Scanning Electron Microscopy (SEM) and colorimetric measurements.The results obtained from the original adobes have been compared with fresh soils from horizons related with pre-Hispanic activity. The results indicate presence of amorphous materials and neo-mineral formation besides feldspars and opal. The amorphous phases have been identified by NMR-MAS and SEM.Differences were found in the composition from the adobe used for the joints, mainly in the clay fraction, that can be distinguished by color and that guided to group the information acquired.These results provide new information on the composition and microstructure of adobes from the Gran Pirámide of Cholula. Further studies will involve soil physics methods and erosion tests to complete the task of having a comprehensive knowledge of the earth architecture of the pyramid.

Mechanism and Structural Analysis of the Thermal Activation of Coal-Gangue

This paper presents a study of the thermal activation of coal-gangue. The samples were tested and analyzed using Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Magic Angle Spin Nuclear Magnetic Resonance (MAS NMR), Scanning Electron Microscopy (SEM), and Atomic Emission Spectroscopy (ICP-AES). Results indicate that the degree of coal-gangue activation varies with variations in the phase structure and coordination of aluminum at different temperatures.

Synthesis of Epoxides Catalyzed by a Halide-Free Reaction-Controlled Phase-Transfer Catalytic System: [(CH3(CH2)17)2N(CH3)2]3[PW4O32]/H2O2/Dioxan/Olefin

The epoxidation of alkenes was successfully catalyzed by a recyclable catalytic system: [(CH3(CH2)17)2N(CH3)2]3[PW4O32]/H2O2/dioxan/olefin. This new catalytic system is not only capable of catalyzing homogeneous epoxidation of alkenes with a unique reaction-controlled phase-transfer character, but also avoids the use of chlorinated solvents. The reactions were conducted in a biphasic mixture of aqueous H2O2/dioxan, and many kinds of alkenes could be efficiently converted to the corresponding epoxides in high yields. Both new and used [(CH3(CH2)17)2N(CH3)2]3[PW4O32] catalyst was characterized by 31P magic angle spin NMR, and IR.

Corrigendum to: Synthesis of Epoxides Catalyzed by a Halide-Free Reaction-Controlled Phase-Transfer Catalytic System: [(CH3(CH2)17)2N(CH3)2]3[PW4O32]/H2O2/Dioxan/Olefin

The epoxidation of alkenes was successfully catalyzed by a recyclable catalytic system: [(CH3(CH2)17)2N(CH3)2]3[PW4O32]/H2O2/dioxan/olefin. This new catalytic system is not only capable of catalyzing homogeneous epoxidation of alkenes with a unique reaction-controlled phase-transfer character, but also avoids the use of chlorinated solvents. The reactions were conducted in a biphasic mixture of aqueous H2O2/dioxan, and many kinds of alkenes could be efficiently converted to the corresponding epoxides in high yields. Both new and used [(CH3(CH2)17)2N(CH3)2]3[PW4O32] catalyst was characterized by 31P magic angle spin NMR, and IR.